linux-sg2042/drivers/media/v4l2-core/v4l2-compat-ioctl32.c

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/*
* ioctl32.c: Conversion between 32bit and 64bit native ioctls.
* Separated from fs stuff by Arnd Bergmann <arnd@arndb.de>
*
* Copyright (C) 1997-2000 Jakub Jelinek (jakub@redhat.com)
* Copyright (C) 1998 Eddie C. Dost (ecd@skynet.be)
* Copyright (C) 2001,2002 Andi Kleen, SuSE Labs
* Copyright (C) 2003 Pavel Machek (pavel@ucw.cz)
* Copyright (C) 2005 Philippe De Muyter (phdm@macqel.be)
* Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
*
* These routines maintain argument size conversion between 32bit and 64bit
* ioctls.
*/
#include <linux/compat.h>
#include <linux/module.h>
#include <linux/videodev2.h>
#include <linux/v4l2-subdev.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-ioctl.h>
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
/* Use the same argument order as copy_in_user */
#define assign_in_user(to, from) \
({ \
typeof(*from) __assign_tmp; \
\
get_user(__assign_tmp, from) || put_user(__assign_tmp, to); \
})
static long native_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
long ret = -ENOIOCTLCMD;
if (file->f_op->unlocked_ioctl)
ret = file->f_op->unlocked_ioctl(file, cmd, arg);
return ret;
}
struct v4l2_clip32 {
struct v4l2_rect c;
compat_caddr_t next;
};
struct v4l2_window32 {
struct v4l2_rect w;
__u32 field; /* enum v4l2_field */
__u32 chromakey;
compat_caddr_t clips; /* actually struct v4l2_clip32 * */
__u32 clipcount;
compat_caddr_t bitmap;
__u8 global_alpha;
};
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int get_v4l2_window32(struct v4l2_window __user *kp,
struct v4l2_window32 __user *up,
void __user *aux_buf, u32 aux_space)
{
struct v4l2_clip32 __user *uclips;
struct v4l2_clip __user *kclips;
compat_caddr_t p;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
u32 clipcount;
if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
copy_in_user(&kp->w, &up->w, sizeof(up->w)) ||
assign_in_user(&kp->field, &up->field) ||
assign_in_user(&kp->chromakey, &up->chromakey) ||
assign_in_user(&kp->global_alpha, &up->global_alpha) ||
get_user(clipcount, &up->clipcount) ||
put_user(clipcount, &kp->clipcount))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (clipcount > 2048)
return -EINVAL;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (!clipcount)
return put_user(NULL, &kp->clips);
if (get_user(p, &up->clips))
return -EFAULT;
uclips = compat_ptr(p);
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (aux_space < clipcount * sizeof(*kclips))
return -EFAULT;
kclips = aux_buf;
if (put_user(kclips, &kp->clips))
return -EFAULT;
while (clipcount--) {
if (copy_in_user(&kclips->c, &uclips->c, sizeof(uclips->c)))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (put_user(clipcount ? kclips + 1 : NULL, &kclips->next))
return -EFAULT;
uclips++;
kclips++;
}
return 0;
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int put_v4l2_window32(struct v4l2_window __user *kp,
struct v4l2_window32 __user *up)
{
media: v4l2-compat-ioctl32: don't oops on overlay At put_v4l2_window32(), it tries to access kp->clips. However, kp points to an userspace pointer. So, it should be obtained via get_user(), otherwise it can OOPS: vivid-000: ================== END STATUS ================== BUG: unable to handle kernel paging request at 00000000fffb18e0 IP: [<ffffffffc05468d9>] __put_v4l2_format32+0x169/0x220 [videodev] PGD 3f5776067 PUD 3f576f067 PMD 3f5769067 PTE 800000042548f067 Oops: 0001 [#1] SMP Modules linked in: vivid videobuf2_vmalloc videobuf2_memops v4l2_dv_timings videobuf2_core v4l2_common videodev media xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables bluetooth rfkill binfmt_misc snd_hda_codec_hdmi i915 snd_hda_intel snd_hda_controller snd_hda_codec intel_rapl x86_pkg_temp_thermal snd_hwdep intel_powerclamp snd_pcm coretemp snd_seq_midi kvm_intel kvm snd_seq_midi_event snd_rawmidi i2c_algo_bit drm_kms_helper snd_seq drm crct10dif_pclmul e1000e snd_seq_device crc32_pclmul snd_timer ghash_clmulni_intel snd mei_me mei ptp pps_core soundcore lpc_ich video crc32c_intel [last unloaded: media] CPU: 2 PID: 28332 Comm: v4l2-compliance Not tainted 3.18.102+ #107 Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0364.2017.0511.0949 05/11/2017 task: ffff8804293f8000 ti: ffff8803f5640000 task.ti: ffff8803f5640000 RIP: 0010:[<ffffffffc05468d9>] [<ffffffffc05468d9>] __put_v4l2_format32+0x169/0x220 [videodev] RSP: 0018:ffff8803f5643e28 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000fffb1ab4 RDX: 00000000fffb1a68 RSI: 00000000fffb18d8 RDI: 00000000fffb1aa8 RBP: ffff8803f5643e48 R08: 0000000000000001 R09: ffff8803f54b0378 R10: 0000000000000000 R11: 0000000000000168 R12: 00000000fffb18c0 R13: 00000000fffb1a94 R14: 00000000fffb18c8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff880456d00000(0063) knlGS:00000000f7100980 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000fffb18e0 CR3: 00000003f552b000 CR4: 00000000003407e0 Stack: 00000000fffb1a94 00000000c0cc5640 0000000000000056 ffff8804274f3600 ffff8803f5643ed0 ffffffffc0547e16 0000000000000003 ffff8803f5643eb0 ffffffff81301460 ffff88009db44b01 ffff880441942520 ffff8800c0d05640 Call Trace: [<ffffffffc0547e16>] v4l2_compat_ioctl32+0x12d6/0x1b1d [videodev] [<ffffffff81301460>] ? file_has_perm+0x70/0xc0 [<ffffffff81252a2c>] compat_SyS_ioctl+0xec/0x1200 [<ffffffff8173241a>] sysenter_dispatch+0x7/0x21 Code: 00 00 48 8b 80 48 c0 ff ff 48 83 e8 38 49 39 c6 0f 87 2b ff ff ff 49 8d 45 1c e8 a3 ce e3 c0 85 c0 0f 85 1a ff ff ff 41 8d 40 ff <4d> 8b 64 24 20 41 89 d5 48 8d 44 40 03 4d 8d 34 c4 eb 15 0f 1f RIP [<ffffffffc05468d9>] __put_v4l2_format32+0x169/0x220 [videodev] RSP <ffff8803f5643e28> CR2: 00000000fffb18e0 Tested with vivid driver on Kernel v3.18.102. Same bug happens upstream too: BUG: KASAN: user-memory-access in __put_v4l2_format32+0x98/0x4d0 [videodev] Read of size 8 at addr 00000000ffe48400 by task v4l2-compliance/8713 CPU: 0 PID: 8713 Comm: v4l2-compliance Not tainted 4.16.0-rc4+ #108 Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0364.2017.0511.0949 05/11/2017 Call Trace: dump_stack+0x5c/0x7c kasan_report+0x164/0x380 ? __put_v4l2_format32+0x98/0x4d0 [videodev] __put_v4l2_format32+0x98/0x4d0 [videodev] v4l2_compat_ioctl32+0x1aec/0x27a0 [videodev] ? __fsnotify_inode_delete+0x20/0x20 ? __put_v4l2_format32+0x4d0/0x4d0 [videodev] compat_SyS_ioctl+0x646/0x14d0 ? do_ioctl+0x30/0x30 do_fast_syscall_32+0x191/0x3f4 entry_SYSENTER_compat+0x6b/0x7a ================================================================== Disabling lock debugging due to kernel taint BUG: unable to handle kernel paging request at 00000000ffe48400 IP: __put_v4l2_format32+0x98/0x4d0 [videodev] PGD 3a22fb067 P4D 3a22fb067 PUD 39b6f0067 PMD 39b6f1067 PTE 80000003256af067 Oops: 0001 [#1] SMP KASAN Modules linked in: vivid videobuf2_vmalloc videobuf2_dma_contig videobuf2_memops v4l2_tpg v4l2_dv_timings videobuf2_v4l2 videobuf2_common v4l2_common videodev xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack libcrc32c tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables bluetooth rfkill ecdh_generic binfmt_misc snd_hda_codec_hdmi intel_rapl x86_pkg_temp_thermal intel_powerclamp i915 coretemp snd_hda_intel snd_hda_codec kvm_intel snd_hwdep snd_hda_core kvm snd_pcm irqbypass crct10dif_pclmul crc32_pclmul snd_seq_midi ghash_clmulni_intel snd_seq_midi_event i2c_algo_bit intel_cstate snd_rawmidi intel_uncore snd_seq drm_kms_helper e1000e snd_seq_device snd_timer intel_rapl_perf drm ptp snd mei_me mei lpc_ich pps_core soundcore video crc32c_intel CPU: 0 PID: 8713 Comm: v4l2-compliance Tainted: G B 4.16.0-rc4+ #108 Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0364.2017.0511.0949 05/11/2017 RIP: 0010:__put_v4l2_format32+0x98/0x4d0 [videodev] RSP: 0018:ffff8803b9be7d30 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff8803ac983e80 RCX: ffffffff8cd929f2 RDX: 1ffffffff1d0a149 RSI: 0000000000000297 RDI: 0000000000000297 RBP: 00000000ffe485c0 R08: fffffbfff1cf5123 R09: ffffffff8e7a8948 R10: 0000000000000001 R11: fffffbfff1cf5122 R12: 00000000ffe483e0 R13: 00000000ffe485c4 R14: ffff8803ac985918 R15: 00000000ffe483e8 FS: 0000000000000000(0000) GS:ffff880407400000(0063) knlGS:00000000f7a46980 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000ffe48400 CR3: 00000003a83f2003 CR4: 00000000003606f0 Call Trace: v4l2_compat_ioctl32+0x1aec/0x27a0 [videodev] ? __fsnotify_inode_delete+0x20/0x20 ? __put_v4l2_format32+0x4d0/0x4d0 [videodev] compat_SyS_ioctl+0x646/0x14d0 ? do_ioctl+0x30/0x30 do_fast_syscall_32+0x191/0x3f4 entry_SYSENTER_compat+0x6b/0x7a Code: 4c 89 f7 4d 8d 7c 24 08 e8 e6 a4 69 cb 48 8b 83 98 1a 00 00 48 83 e8 10 49 39 c7 0f 87 9d 01 00 00 49 8d 7c 24 20 e8 c8 a4 69 cb <4d> 8b 74 24 20 4c 89 ef 4c 89 fe ba 10 00 00 00 e8 23 d9 08 cc RIP: __put_v4l2_format32+0x98/0x4d0 [videodev] RSP: ffff8803b9be7d30 CR2: 00000000ffe48400 cc: stable@vger.kernel.org Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com> Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2018-03-29 01:59:22 +08:00
struct v4l2_clip __user *kclips;
struct v4l2_clip32 __user *uclips;
compat_caddr_t p;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
u32 clipcount;
if (copy_in_user(&up->w, &kp->w, sizeof(kp->w)) ||
assign_in_user(&up->field, &kp->field) ||
assign_in_user(&up->chromakey, &kp->chromakey) ||
assign_in_user(&up->global_alpha, &kp->global_alpha) ||
get_user(clipcount, &kp->clipcount) ||
put_user(clipcount, &up->clipcount))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (!clipcount)
return 0;
media: v4l2-compat-ioctl32: don't oops on overlay At put_v4l2_window32(), it tries to access kp->clips. However, kp points to an userspace pointer. So, it should be obtained via get_user(), otherwise it can OOPS: vivid-000: ================== END STATUS ================== BUG: unable to handle kernel paging request at 00000000fffb18e0 IP: [<ffffffffc05468d9>] __put_v4l2_format32+0x169/0x220 [videodev] PGD 3f5776067 PUD 3f576f067 PMD 3f5769067 PTE 800000042548f067 Oops: 0001 [#1] SMP Modules linked in: vivid videobuf2_vmalloc videobuf2_memops v4l2_dv_timings videobuf2_core v4l2_common videodev media xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables bluetooth rfkill binfmt_misc snd_hda_codec_hdmi i915 snd_hda_intel snd_hda_controller snd_hda_codec intel_rapl x86_pkg_temp_thermal snd_hwdep intel_powerclamp snd_pcm coretemp snd_seq_midi kvm_intel kvm snd_seq_midi_event snd_rawmidi i2c_algo_bit drm_kms_helper snd_seq drm crct10dif_pclmul e1000e snd_seq_device crc32_pclmul snd_timer ghash_clmulni_intel snd mei_me mei ptp pps_core soundcore lpc_ich video crc32c_intel [last unloaded: media] CPU: 2 PID: 28332 Comm: v4l2-compliance Not tainted 3.18.102+ #107 Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0364.2017.0511.0949 05/11/2017 task: ffff8804293f8000 ti: ffff8803f5640000 task.ti: ffff8803f5640000 RIP: 0010:[<ffffffffc05468d9>] [<ffffffffc05468d9>] __put_v4l2_format32+0x169/0x220 [videodev] RSP: 0018:ffff8803f5643e28 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000fffb1ab4 RDX: 00000000fffb1a68 RSI: 00000000fffb18d8 RDI: 00000000fffb1aa8 RBP: ffff8803f5643e48 R08: 0000000000000001 R09: ffff8803f54b0378 R10: 0000000000000000 R11: 0000000000000168 R12: 00000000fffb18c0 R13: 00000000fffb1a94 R14: 00000000fffb18c8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff880456d00000(0063) knlGS:00000000f7100980 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000fffb18e0 CR3: 00000003f552b000 CR4: 00000000003407e0 Stack: 00000000fffb1a94 00000000c0cc5640 0000000000000056 ffff8804274f3600 ffff8803f5643ed0 ffffffffc0547e16 0000000000000003 ffff8803f5643eb0 ffffffff81301460 ffff88009db44b01 ffff880441942520 ffff8800c0d05640 Call Trace: [<ffffffffc0547e16>] v4l2_compat_ioctl32+0x12d6/0x1b1d [videodev] [<ffffffff81301460>] ? file_has_perm+0x70/0xc0 [<ffffffff81252a2c>] compat_SyS_ioctl+0xec/0x1200 [<ffffffff8173241a>] sysenter_dispatch+0x7/0x21 Code: 00 00 48 8b 80 48 c0 ff ff 48 83 e8 38 49 39 c6 0f 87 2b ff ff ff 49 8d 45 1c e8 a3 ce e3 c0 85 c0 0f 85 1a ff ff ff 41 8d 40 ff <4d> 8b 64 24 20 41 89 d5 48 8d 44 40 03 4d 8d 34 c4 eb 15 0f 1f RIP [<ffffffffc05468d9>] __put_v4l2_format32+0x169/0x220 [videodev] RSP <ffff8803f5643e28> CR2: 00000000fffb18e0 Tested with vivid driver on Kernel v3.18.102. Same bug happens upstream too: BUG: KASAN: user-memory-access in __put_v4l2_format32+0x98/0x4d0 [videodev] Read of size 8 at addr 00000000ffe48400 by task v4l2-compliance/8713 CPU: 0 PID: 8713 Comm: v4l2-compliance Not tainted 4.16.0-rc4+ #108 Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0364.2017.0511.0949 05/11/2017 Call Trace: dump_stack+0x5c/0x7c kasan_report+0x164/0x380 ? __put_v4l2_format32+0x98/0x4d0 [videodev] __put_v4l2_format32+0x98/0x4d0 [videodev] v4l2_compat_ioctl32+0x1aec/0x27a0 [videodev] ? __fsnotify_inode_delete+0x20/0x20 ? __put_v4l2_format32+0x4d0/0x4d0 [videodev] compat_SyS_ioctl+0x646/0x14d0 ? do_ioctl+0x30/0x30 do_fast_syscall_32+0x191/0x3f4 entry_SYSENTER_compat+0x6b/0x7a ================================================================== Disabling lock debugging due to kernel taint BUG: unable to handle kernel paging request at 00000000ffe48400 IP: __put_v4l2_format32+0x98/0x4d0 [videodev] PGD 3a22fb067 P4D 3a22fb067 PUD 39b6f0067 PMD 39b6f1067 PTE 80000003256af067 Oops: 0001 [#1] SMP KASAN Modules linked in: vivid videobuf2_vmalloc videobuf2_dma_contig videobuf2_memops v4l2_tpg v4l2_dv_timings videobuf2_v4l2 videobuf2_common v4l2_common videodev xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack libcrc32c tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables bluetooth rfkill ecdh_generic binfmt_misc snd_hda_codec_hdmi intel_rapl x86_pkg_temp_thermal intel_powerclamp i915 coretemp snd_hda_intel snd_hda_codec kvm_intel snd_hwdep snd_hda_core kvm snd_pcm irqbypass crct10dif_pclmul crc32_pclmul snd_seq_midi ghash_clmulni_intel snd_seq_midi_event i2c_algo_bit intel_cstate snd_rawmidi intel_uncore snd_seq drm_kms_helper e1000e snd_seq_device snd_timer intel_rapl_perf drm ptp snd mei_me mei lpc_ich pps_core soundcore video crc32c_intel CPU: 0 PID: 8713 Comm: v4l2-compliance Tainted: G B 4.16.0-rc4+ #108 Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0364.2017.0511.0949 05/11/2017 RIP: 0010:__put_v4l2_format32+0x98/0x4d0 [videodev] RSP: 0018:ffff8803b9be7d30 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff8803ac983e80 RCX: ffffffff8cd929f2 RDX: 1ffffffff1d0a149 RSI: 0000000000000297 RDI: 0000000000000297 RBP: 00000000ffe485c0 R08: fffffbfff1cf5123 R09: ffffffff8e7a8948 R10: 0000000000000001 R11: fffffbfff1cf5122 R12: 00000000ffe483e0 R13: 00000000ffe485c4 R14: ffff8803ac985918 R15: 00000000ffe483e8 FS: 0000000000000000(0000) GS:ffff880407400000(0063) knlGS:00000000f7a46980 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000ffe48400 CR3: 00000003a83f2003 CR4: 00000000003606f0 Call Trace: v4l2_compat_ioctl32+0x1aec/0x27a0 [videodev] ? __fsnotify_inode_delete+0x20/0x20 ? __put_v4l2_format32+0x4d0/0x4d0 [videodev] compat_SyS_ioctl+0x646/0x14d0 ? do_ioctl+0x30/0x30 do_fast_syscall_32+0x191/0x3f4 entry_SYSENTER_compat+0x6b/0x7a Code: 4c 89 f7 4d 8d 7c 24 08 e8 e6 a4 69 cb 48 8b 83 98 1a 00 00 48 83 e8 10 49 39 c7 0f 87 9d 01 00 00 49 8d 7c 24 20 e8 c8 a4 69 cb <4d> 8b 74 24 20 4c 89 ef 4c 89 fe ba 10 00 00 00 e8 23 d9 08 cc RIP: __put_v4l2_format32+0x98/0x4d0 [videodev] RSP: ffff8803b9be7d30 CR2: 00000000ffe48400 cc: stable@vger.kernel.org Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com> Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2018-03-29 01:59:22 +08:00
if (get_user(kclips, &kp->clips))
return -EFAULT;
if (get_user(p, &up->clips))
return -EFAULT;
uclips = compat_ptr(p);
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
while (clipcount--) {
if (copy_in_user(&uclips->c, &kclips->c, sizeof(uclips->c)))
return -EFAULT;
uclips++;
kclips++;
}
return 0;
}
struct v4l2_format32 {
[media] v4l2: use __u32 rather than enums in ioctl() structs V4L2 uses the enum type in IOCTL arguments in IOCTLs that were defined until the use of enum was considered less than ideal. Recently Rémi Denis-Courmont brought up the issue by proposing a patch to convert the enums to unsigned: <URL:http://www.spinics.net/lists/linux-media/msg46167.html> This sparked a long discussion where another solution to the issue was proposed: two sets of IOCTL structures, one with __u32 and the other with enums, and conversion code between the two: <URL:http://www.spinics.net/lists/linux-media/msg47168.html> Both approaches implement a complete solution that resolves the problem. The first one is simple but requires assuming enums and __u32 are the same in size (so we won't break the ABI) while the second one is more complex and less clean but does not require making that assumption. The issue boils down to whether enums are fundamentally different from __u32 or not, and can the former be substituted by the latter. During the discussion it was concluded that the __u32 has the same size as enums on all archs Linux is supported: it has not been shown that replacing those enums in IOCTL arguments would break neither source or binary compatibility. If no such reason is found, just replacing the enums with __u32s is the way to go. This is what this patch does. This patch is slightly different from Remi's first RFC (link above): it uses __u32 instead of unsigned and also changes the arguments of VIDIOC_G_PRIORITY and VIDIOC_S_PRIORITY. Signed-off-by: Rémi Denis-Courmont <remi@remlab.net> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-05-10 13:02:07 +08:00
__u32 type; /* enum v4l2_buf_type */
union {
struct v4l2_pix_format pix;
struct v4l2_pix_format_mplane pix_mp;
struct v4l2_window32 win;
struct v4l2_vbi_format vbi;
struct v4l2_sliced_vbi_format sliced;
struct v4l2_sdr_format sdr;
struct v4l2_meta_format meta;
__u8 raw_data[200]; /* user-defined */
} fmt;
};
/**
* struct v4l2_create_buffers32 - VIDIOC_CREATE_BUFS32 argument
* @index: on return, index of the first created buffer
* @count: entry: number of requested buffers,
* return: number of created buffers
* @memory: buffer memory type
* @format: frame format, for which buffers are requested
* @reserved: future extensions
*/
struct v4l2_create_buffers32 {
__u32 index;
__u32 count;
[media] v4l2: use __u32 rather than enums in ioctl() structs V4L2 uses the enum type in IOCTL arguments in IOCTLs that were defined until the use of enum was considered less than ideal. Recently Rémi Denis-Courmont brought up the issue by proposing a patch to convert the enums to unsigned: <URL:http://www.spinics.net/lists/linux-media/msg46167.html> This sparked a long discussion where another solution to the issue was proposed: two sets of IOCTL structures, one with __u32 and the other with enums, and conversion code between the two: <URL:http://www.spinics.net/lists/linux-media/msg47168.html> Both approaches implement a complete solution that resolves the problem. The first one is simple but requires assuming enums and __u32 are the same in size (so we won't break the ABI) while the second one is more complex and less clean but does not require making that assumption. The issue boils down to whether enums are fundamentally different from __u32 or not, and can the former be substituted by the latter. During the discussion it was concluded that the __u32 has the same size as enums on all archs Linux is supported: it has not been shown that replacing those enums in IOCTL arguments would break neither source or binary compatibility. If no such reason is found, just replacing the enums with __u32s is the way to go. This is what this patch does. This patch is slightly different from Remi's first RFC (link above): it uses __u32 instead of unsigned and also changes the arguments of VIDIOC_G_PRIORITY and VIDIOC_S_PRIORITY. Signed-off-by: Rémi Denis-Courmont <remi@remlab.net> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-05-10 13:02:07 +08:00
__u32 memory; /* enum v4l2_memory */
struct v4l2_format32 format;
__u32 reserved[8];
};
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int __bufsize_v4l2_format(struct v4l2_format32 __user *up, u32 *size)
{
u32 type;
if (get_user(type, &up->type))
return -EFAULT;
switch (type) {
case V4L2_BUF_TYPE_VIDEO_OVERLAY:
case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY: {
u32 clipcount;
if (get_user(clipcount, &up->fmt.win.clipcount))
return -EFAULT;
if (clipcount > 2048)
return -EINVAL;
*size = clipcount * sizeof(struct v4l2_clip);
return 0;
}
default:
*size = 0;
return 0;
}
}
static int bufsize_v4l2_format(struct v4l2_format32 __user *up, u32 *size)
{
if (!access_ok(VERIFY_READ, up, sizeof(*up)))
return -EFAULT;
return __bufsize_v4l2_format(up, size);
}
static int __get_v4l2_format32(struct v4l2_format __user *kp,
struct v4l2_format32 __user *up,
void __user *aux_buf, u32 aux_space)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
u32 type;
if (get_user(type, &up->type) || put_user(type, &kp->type))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
switch (type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&kp->fmt.pix, &up->fmt.pix,
sizeof(kp->fmt.pix)) ? -EFAULT : 0;
case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&kp->fmt.pix_mp, &up->fmt.pix_mp,
sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
case V4L2_BUF_TYPE_VIDEO_OVERLAY:
case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return get_v4l2_window32(&kp->fmt.win, &up->fmt.win,
aux_buf, aux_space);
case V4L2_BUF_TYPE_VBI_CAPTURE:
case V4L2_BUF_TYPE_VBI_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&kp->fmt.vbi, &up->fmt.vbi,
sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&kp->fmt.sliced, &up->fmt.sliced,
sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
case V4L2_BUF_TYPE_SDR_CAPTURE:
case V4L2_BUF_TYPE_SDR_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&kp->fmt.sdr, &up->fmt.sdr,
sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
case V4L2_BUF_TYPE_META_CAPTURE:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&kp->fmt.meta, &up->fmt.meta,
sizeof(kp->fmt.meta)) ? -EFAULT : 0;
default:
return -EINVAL;
}
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int get_v4l2_format32(struct v4l2_format __user *kp,
struct v4l2_format32 __user *up,
void __user *aux_buf, u32 aux_space)
{
if (!access_ok(VERIFY_READ, up, sizeof(*up)))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return __get_v4l2_format32(kp, up, aux_buf, aux_space);
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int bufsize_v4l2_create(struct v4l2_create_buffers32 __user *up,
u32 *size)
{
if (!access_ok(VERIFY_READ, up, sizeof(*up)))
return -EFAULT;
return __bufsize_v4l2_format(&up->format, size);
}
static int get_v4l2_create32(struct v4l2_create_buffers __user *kp,
struct v4l2_create_buffers32 __user *up,
void __user *aux_buf, u32 aux_space)
{
if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
copy_in_user(kp, up,
offsetof(struct v4l2_create_buffers32, format)))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return __get_v4l2_format32(&kp->format, &up->format,
aux_buf, aux_space);
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int __put_v4l2_format32(struct v4l2_format __user *kp,
struct v4l2_format32 __user *up)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
u32 type;
if (get_user(type, &kp->type))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
switch (type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&up->fmt.pix, &kp->fmt.pix,
sizeof(kp->fmt.pix)) ? -EFAULT : 0;
case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&up->fmt.pix_mp, &kp->fmt.pix_mp,
sizeof(kp->fmt.pix_mp)) ? -EFAULT : 0;
case V4L2_BUF_TYPE_VIDEO_OVERLAY:
case V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY:
return put_v4l2_window32(&kp->fmt.win, &up->fmt.win);
case V4L2_BUF_TYPE_VBI_CAPTURE:
case V4L2_BUF_TYPE_VBI_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&up->fmt.vbi, &kp->fmt.vbi,
sizeof(kp->fmt.vbi)) ? -EFAULT : 0;
case V4L2_BUF_TYPE_SLICED_VBI_CAPTURE:
case V4L2_BUF_TYPE_SLICED_VBI_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&up->fmt.sliced, &kp->fmt.sliced,
sizeof(kp->fmt.sliced)) ? -EFAULT : 0;
case V4L2_BUF_TYPE_SDR_CAPTURE:
case V4L2_BUF_TYPE_SDR_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&up->fmt.sdr, &kp->fmt.sdr,
sizeof(kp->fmt.sdr)) ? -EFAULT : 0;
case V4L2_BUF_TYPE_META_CAPTURE:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
return copy_in_user(&up->fmt.meta, &kp->fmt.meta,
sizeof(kp->fmt.meta)) ? -EFAULT : 0;
default:
return -EINVAL;
}
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int put_v4l2_format32(struct v4l2_format __user *kp,
struct v4l2_format32 __user *up)
{
if (!access_ok(VERIFY_WRITE, up, sizeof(*up)))
return -EFAULT;
return __put_v4l2_format32(kp, up);
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int put_v4l2_create32(struct v4l2_create_buffers __user *kp,
struct v4l2_create_buffers32 __user *up)
{
if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
copy_in_user(up, kp,
offsetof(struct v4l2_create_buffers32, format)) ||
copy_in_user(up->reserved, kp->reserved, sizeof(kp->reserved)))
return -EFAULT;
return __put_v4l2_format32(&kp->format, &up->format);
}
struct v4l2_standard32 {
__u32 index;
compat_u64 id;
__u8 name[24];
struct v4l2_fract frameperiod; /* Frames, not fields */
__u32 framelines;
__u32 reserved[4];
};
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int get_v4l2_standard32(struct v4l2_standard __user *kp,
struct v4l2_standard32 __user *up)
{
/* other fields are not set by the user, nor used by the driver */
if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
assign_in_user(&kp->index, &up->index))
return -EFAULT;
return 0;
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int put_v4l2_standard32(struct v4l2_standard __user *kp,
struct v4l2_standard32 __user *up)
{
if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
assign_in_user(&up->index, &kp->index) ||
assign_in_user(&up->id, &kp->id) ||
copy_in_user(up->name, kp->name, sizeof(up->name)) ||
copy_in_user(&up->frameperiod, &kp->frameperiod,
sizeof(up->frameperiod)) ||
assign_in_user(&up->framelines, &kp->framelines) ||
copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
return -EFAULT;
return 0;
}
struct v4l2_plane32 {
__u32 bytesused;
__u32 length;
union {
__u32 mem_offset;
compat_long_t userptr;
__s32 fd;
} m;
__u32 data_offset;
__u32 reserved[11];
};
struct v4l2_buffer32 {
__u32 index;
[media] v4l2: use __u32 rather than enums in ioctl() structs V4L2 uses the enum type in IOCTL arguments in IOCTLs that were defined until the use of enum was considered less than ideal. Recently Rémi Denis-Courmont brought up the issue by proposing a patch to convert the enums to unsigned: <URL:http://www.spinics.net/lists/linux-media/msg46167.html> This sparked a long discussion where another solution to the issue was proposed: two sets of IOCTL structures, one with __u32 and the other with enums, and conversion code between the two: <URL:http://www.spinics.net/lists/linux-media/msg47168.html> Both approaches implement a complete solution that resolves the problem. The first one is simple but requires assuming enums and __u32 are the same in size (so we won't break the ABI) while the second one is more complex and less clean but does not require making that assumption. The issue boils down to whether enums are fundamentally different from __u32 or not, and can the former be substituted by the latter. During the discussion it was concluded that the __u32 has the same size as enums on all archs Linux is supported: it has not been shown that replacing those enums in IOCTL arguments would break neither source or binary compatibility. If no such reason is found, just replacing the enums with __u32s is the way to go. This is what this patch does. This patch is slightly different from Remi's first RFC (link above): it uses __u32 instead of unsigned and also changes the arguments of VIDIOC_G_PRIORITY and VIDIOC_S_PRIORITY. Signed-off-by: Rémi Denis-Courmont <remi@remlab.net> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-05-10 13:02:07 +08:00
__u32 type; /* enum v4l2_buf_type */
__u32 bytesused;
__u32 flags;
[media] v4l2: use __u32 rather than enums in ioctl() structs V4L2 uses the enum type in IOCTL arguments in IOCTLs that were defined until the use of enum was considered less than ideal. Recently Rémi Denis-Courmont brought up the issue by proposing a patch to convert the enums to unsigned: <URL:http://www.spinics.net/lists/linux-media/msg46167.html> This sparked a long discussion where another solution to the issue was proposed: two sets of IOCTL structures, one with __u32 and the other with enums, and conversion code between the two: <URL:http://www.spinics.net/lists/linux-media/msg47168.html> Both approaches implement a complete solution that resolves the problem. The first one is simple but requires assuming enums and __u32 are the same in size (so we won't break the ABI) while the second one is more complex and less clean but does not require making that assumption. The issue boils down to whether enums are fundamentally different from __u32 or not, and can the former be substituted by the latter. During the discussion it was concluded that the __u32 has the same size as enums on all archs Linux is supported: it has not been shown that replacing those enums in IOCTL arguments would break neither source or binary compatibility. If no such reason is found, just replacing the enums with __u32s is the way to go. This is what this patch does. This patch is slightly different from Remi's first RFC (link above): it uses __u32 instead of unsigned and also changes the arguments of VIDIOC_G_PRIORITY and VIDIOC_S_PRIORITY. Signed-off-by: Rémi Denis-Courmont <remi@remlab.net> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-05-10 13:02:07 +08:00
__u32 field; /* enum v4l2_field */
struct compat_timeval timestamp;
struct v4l2_timecode timecode;
__u32 sequence;
/* memory location */
[media] v4l2: use __u32 rather than enums in ioctl() structs V4L2 uses the enum type in IOCTL arguments in IOCTLs that were defined until the use of enum was considered less than ideal. Recently Rémi Denis-Courmont brought up the issue by proposing a patch to convert the enums to unsigned: <URL:http://www.spinics.net/lists/linux-media/msg46167.html> This sparked a long discussion where another solution to the issue was proposed: two sets of IOCTL structures, one with __u32 and the other with enums, and conversion code between the two: <URL:http://www.spinics.net/lists/linux-media/msg47168.html> Both approaches implement a complete solution that resolves the problem. The first one is simple but requires assuming enums and __u32 are the same in size (so we won't break the ABI) while the second one is more complex and less clean but does not require making that assumption. The issue boils down to whether enums are fundamentally different from __u32 or not, and can the former be substituted by the latter. During the discussion it was concluded that the __u32 has the same size as enums on all archs Linux is supported: it has not been shown that replacing those enums in IOCTL arguments would break neither source or binary compatibility. If no such reason is found, just replacing the enums with __u32s is the way to go. This is what this patch does. This patch is slightly different from Remi's first RFC (link above): it uses __u32 instead of unsigned and also changes the arguments of VIDIOC_G_PRIORITY and VIDIOC_S_PRIORITY. Signed-off-by: Rémi Denis-Courmont <remi@remlab.net> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2012-05-10 13:02:07 +08:00
__u32 memory; /* enum v4l2_memory */
union {
__u32 offset;
compat_long_t userptr;
compat_caddr_t planes;
__s32 fd;
} m;
__u32 length;
__u32 reserved2;
__u32 reserved;
};
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int get_v4l2_plane32(struct v4l2_plane __user *up,
struct v4l2_plane32 __user *up32,
enum v4l2_memory memory)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
compat_ulong_t p;
if (copy_in_user(up, up32, 2 * sizeof(__u32)) ||
copy_in_user(&up->data_offset, &up32->data_offset,
sizeof(up->data_offset)))
return -EFAULT;
switch (memory) {
case V4L2_MEMORY_MMAP:
case V4L2_MEMORY_OVERLAY:
if (copy_in_user(&up->m.mem_offset, &up32->m.mem_offset,
sizeof(up32->m.mem_offset)))
return -EFAULT;
break;
case V4L2_MEMORY_USERPTR:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (get_user(p, &up32->m.userptr) ||
put_user((unsigned long)compat_ptr(p), &up->m.userptr))
return -EFAULT;
break;
case V4L2_MEMORY_DMABUF:
if (copy_in_user(&up->m.fd, &up32->m.fd, sizeof(up32->m.fd)))
return -EFAULT;
break;
}
return 0;
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int put_v4l2_plane32(struct v4l2_plane __user *up,
struct v4l2_plane32 __user *up32,
enum v4l2_memory memory)
{
unsigned long p;
if (copy_in_user(up32, up, 2 * sizeof(__u32)) ||
copy_in_user(&up32->data_offset, &up->data_offset,
sizeof(up->data_offset)))
return -EFAULT;
switch (memory) {
case V4L2_MEMORY_MMAP:
case V4L2_MEMORY_OVERLAY:
if (copy_in_user(&up32->m.mem_offset, &up->m.mem_offset,
sizeof(up->m.mem_offset)))
return -EFAULT;
break;
case V4L2_MEMORY_USERPTR:
if (get_user(p, &up->m.userptr) ||
put_user((compat_ulong_t)ptr_to_compat((__force void *)p),
&up32->m.userptr))
return -EFAULT;
break;
case V4L2_MEMORY_DMABUF:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (copy_in_user(&up32->m.fd, &up->m.fd, sizeof(up->m.fd)))
return -EFAULT;
break;
}
return 0;
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int bufsize_v4l2_buffer(struct v4l2_buffer32 __user *up, u32 *size)
{
u32 type;
u32 length;
if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
get_user(type, &up->type) ||
get_user(length, &up->length))
return -EFAULT;
if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
if (length > VIDEO_MAX_PLANES)
return -EINVAL;
/*
* We don't really care if userspace decides to kill itself
* by passing a very big length value
*/
*size = length * sizeof(struct v4l2_plane);
} else {
*size = 0;
}
return 0;
}
static int get_v4l2_buffer32(struct v4l2_buffer __user *kp,
struct v4l2_buffer32 __user *up,
void __user *aux_buf, u32 aux_space)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
u32 type;
u32 length;
enum v4l2_memory memory;
struct v4l2_plane32 __user *uplane32;
struct v4l2_plane __user *uplane;
compat_caddr_t p;
int ret;
if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
assign_in_user(&kp->index, &up->index) ||
get_user(type, &up->type) ||
put_user(type, &kp->type) ||
assign_in_user(&kp->flags, &up->flags) ||
get_user(memory, &up->memory) ||
put_user(memory, &kp->memory) ||
get_user(length, &up->length) ||
put_user(length, &kp->length))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (V4L2_TYPE_IS_OUTPUT(type))
if (assign_in_user(&kp->bytesused, &up->bytesused) ||
assign_in_user(&kp->field, &up->field) ||
assign_in_user(&kp->timestamp.tv_sec,
&up->timestamp.tv_sec) ||
assign_in_user(&kp->timestamp.tv_usec,
&up->timestamp.tv_usec))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
u32 num_planes = length;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (num_planes == 0) {
/*
* num_planes == 0 is legal, e.g. when userspace doesn't
* need planes array on DQBUF
*/
return put_user(NULL, &kp->m.planes);
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (num_planes > VIDEO_MAX_PLANES)
return -EINVAL;
if (get_user(p, &up->m.planes))
return -EFAULT;
uplane32 = compat_ptr(p);
if (!access_ok(VERIFY_READ, uplane32,
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
num_planes * sizeof(*uplane32)))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
/*
* We don't really care if userspace decides to kill itself
* by passing a very big num_planes value
*/
if (aux_space < num_planes * sizeof(*uplane))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
uplane = aux_buf;
if (put_user((__force struct v4l2_plane *)uplane,
&kp->m.planes))
return -EFAULT;
while (num_planes--) {
ret = get_v4l2_plane32(uplane, uplane32, memory);
if (ret)
return ret;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
uplane++;
uplane32++;
}
} else {
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
switch (memory) {
case V4L2_MEMORY_MMAP:
case V4L2_MEMORY_OVERLAY:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (assign_in_user(&kp->m.offset, &up->m.offset))
return -EFAULT;
break;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
case V4L2_MEMORY_USERPTR: {
compat_ulong_t userptr;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (get_user(userptr, &up->m.userptr) ||
put_user((unsigned long)compat_ptr(userptr),
&kp->m.userptr))
return -EFAULT;
break;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
}
case V4L2_MEMORY_DMABUF:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (assign_in_user(&kp->m.fd, &up->m.fd))
return -EFAULT;
break;
}
}
return 0;
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int put_v4l2_buffer32(struct v4l2_buffer __user *kp,
struct v4l2_buffer32 __user *up)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
u32 type;
u32 length;
enum v4l2_memory memory;
struct v4l2_plane32 __user *uplane32;
struct v4l2_plane __user *uplane;
compat_caddr_t p;
int ret;
if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
assign_in_user(&up->index, &kp->index) ||
get_user(type, &kp->type) ||
put_user(type, &up->type) ||
assign_in_user(&up->flags, &kp->flags) ||
get_user(memory, &kp->memory) ||
put_user(memory, &up->memory))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (assign_in_user(&up->bytesused, &kp->bytesused) ||
assign_in_user(&up->field, &kp->field) ||
assign_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
assign_in_user(&up->timestamp.tv_usec, &kp->timestamp.tv_usec) ||
copy_in_user(&up->timecode, &kp->timecode, sizeof(kp->timecode)) ||
assign_in_user(&up->sequence, &kp->sequence) ||
assign_in_user(&up->reserved2, &kp->reserved2) ||
assign_in_user(&up->reserved, &kp->reserved) ||
get_user(length, &kp->length) ||
put_user(length, &up->length))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (V4L2_TYPE_IS_MULTIPLANAR(type)) {
u32 num_planes = length;
if (num_planes == 0)
return 0;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (get_user(uplane, ((__force struct v4l2_plane __user **)&kp->m.planes)))
return -EFAULT;
if (get_user(p, &up->m.planes))
return -EFAULT;
uplane32 = compat_ptr(p);
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
while (num_planes--) {
ret = put_v4l2_plane32(uplane, uplane32, memory);
if (ret)
return ret;
++uplane;
++uplane32;
}
} else {
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
switch (memory) {
case V4L2_MEMORY_MMAP:
case V4L2_MEMORY_OVERLAY:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (assign_in_user(&up->m.offset, &kp->m.offset))
return -EFAULT;
break;
case V4L2_MEMORY_USERPTR:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (assign_in_user(&up->m.userptr, &kp->m.userptr))
return -EFAULT;
break;
case V4L2_MEMORY_DMABUF:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (assign_in_user(&up->m.fd, &kp->m.fd))
return -EFAULT;
break;
}
}
return 0;
}
struct v4l2_framebuffer32 {
__u32 capability;
__u32 flags;
compat_caddr_t base;
struct {
__u32 width;
__u32 height;
__u32 pixelformat;
__u32 field;
__u32 bytesperline;
__u32 sizeimage;
__u32 colorspace;
__u32 priv;
} fmt;
};
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int get_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
struct v4l2_framebuffer32 __user *up)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
compat_caddr_t tmp;
if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
get_user(tmp, &up->base) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
put_user((__force void *)compat_ptr(tmp), &kp->base) ||
assign_in_user(&kp->capability, &up->capability) ||
assign_in_user(&kp->flags, &up->flags) ||
copy_in_user(&kp->fmt, &up->fmt, sizeof(kp->fmt)))
return -EFAULT;
return 0;
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int put_v4l2_framebuffer32(struct v4l2_framebuffer __user *kp,
struct v4l2_framebuffer32 __user *up)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
void *base;
if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
get_user(base, &kp->base) ||
put_user(ptr_to_compat(base), &up->base) ||
assign_in_user(&up->capability, &kp->capability) ||
assign_in_user(&up->flags, &kp->flags) ||
copy_in_user(&up->fmt, &kp->fmt, sizeof(kp->fmt)))
return -EFAULT;
return 0;
}
struct v4l2_input32 {
__u32 index; /* Which input */
__u8 name[32]; /* Label */
__u32 type; /* Type of input */
__u32 audioset; /* Associated audios (bitfield) */
__u32 tuner; /* Associated tuner */
compat_u64 std;
__u32 status;
__u32 capabilities;
__u32 reserved[3];
};
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
/*
* The 64-bit v4l2_input struct has extra padding at the end of the struct.
* Otherwise it is identical to the 32-bit version.
*/
static inline int get_v4l2_input32(struct v4l2_input __user *kp,
struct v4l2_input32 __user *up)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (copy_in_user(kp, up, sizeof(*up)))
return -EFAULT;
return 0;
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static inline int put_v4l2_input32(struct v4l2_input __user *kp,
struct v4l2_input32 __user *up)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (copy_in_user(up, kp, sizeof(*up)))
return -EFAULT;
return 0;
}
struct v4l2_ext_controls32 {
__u32 which;
__u32 count;
__u32 error_idx;
__u32 reserved[2];
compat_caddr_t controls; /* actually struct v4l2_ext_control32 * */
};
struct v4l2_ext_control32 {
__u32 id;
__u32 size;
__u32 reserved2[1];
union {
__s32 value;
__s64 value64;
compat_caddr_t string; /* actually char * */
};
} __attribute__ ((packed));
/* Return true if this control is a pointer type. */
static inline bool ctrl_is_pointer(struct file *file, u32 id)
{
struct video_device *vdev = video_devdata(file);
struct v4l2_fh *fh = NULL;
struct v4l2_ctrl_handler *hdl = NULL;
struct v4l2_query_ext_ctrl qec = { id };
const struct v4l2_ioctl_ops *ops = vdev->ioctl_ops;
if (test_bit(V4L2_FL_USES_V4L2_FH, &vdev->flags))
fh = file->private_data;
if (fh && fh->ctrl_handler)
hdl = fh->ctrl_handler;
else if (vdev->ctrl_handler)
hdl = vdev->ctrl_handler;
if (hdl) {
struct v4l2_ctrl *ctrl = v4l2_ctrl_find(hdl, id);
return ctrl && ctrl->is_ptr;
}
if (!ops || !ops->vidioc_query_ext_ctrl)
return false;
return !ops->vidioc_query_ext_ctrl(file, fh, &qec) &&
(qec.flags & V4L2_CTRL_FLAG_HAS_PAYLOAD);
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int bufsize_v4l2_ext_controls(struct v4l2_ext_controls32 __user *up,
u32 *size)
{
u32 count;
if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
get_user(count, &up->count))
return -EFAULT;
if (count > V4L2_CID_MAX_CTRLS)
return -EINVAL;
*size = count * sizeof(struct v4l2_ext_control);
return 0;
}
static int get_v4l2_ext_controls32(struct file *file,
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
struct v4l2_ext_controls __user *kp,
struct v4l2_ext_controls32 __user *up,
void __user *aux_buf, u32 aux_space)
{
struct v4l2_ext_control32 __user *ucontrols;
struct v4l2_ext_control __user *kcontrols;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
u32 count;
u32 n;
compat_caddr_t p;
if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
assign_in_user(&kp->which, &up->which) ||
get_user(count, &up->count) ||
put_user(count, &kp->count) ||
assign_in_user(&kp->error_idx, &up->error_idx) ||
copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (count == 0)
return put_user(NULL, &kp->controls);
if (count > V4L2_CID_MAX_CTRLS)
return -EINVAL;
if (get_user(p, &up->controls))
return -EFAULT;
ucontrols = compat_ptr(p);
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (!access_ok(VERIFY_READ, ucontrols, count * sizeof(*ucontrols)))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (aux_space < count * sizeof(*kcontrols))
return -EFAULT;
kcontrols = aux_buf;
if (put_user((__force struct v4l2_ext_control *)kcontrols,
&kp->controls))
return -EFAULT;
for (n = 0; n < count; n++) {
[media] v4l2-compat-ioctl32: fix sparse warnings A lot of these warnings are caused by the fact that we don't generally use __user in videodev2.h. Normally the video_usercopy function will copy anything pointed to by pointers into kernel space, so having __user in the struct will only cause lots of warnings in the drivers. But the flip side of that is that you need to add __force casts here. drivers/media/v4l2-core/v4l2-compat-ioctl32.c:337:26: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:337:30: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:338:31: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:338:49: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:343:21: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:346:21: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:349:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:349:46: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:352:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:352:54: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:363:26: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:363:32: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:364:31: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:364:51: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:371:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:371:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:376:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:376:48: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:430:30: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:433:48: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:433:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:501:24: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:507:48: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:507:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:565:18: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:670:22: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:680:29: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:692:55: warning: incorrect type in initializer (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:773:18: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:786:30: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:786:44: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:674:37: warning: dereference of noderef expression drivers/media/v4l2-core/v4l2-compat-ioctl32.c:718:37: warning: dereference of noderef expression Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-08-22 04:07:21 +08:00
u32 id;
if (copy_in_user(kcontrols, ucontrols, sizeof(*ucontrols)))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
[media] v4l2-compat-ioctl32: fix sparse warnings A lot of these warnings are caused by the fact that we don't generally use __user in videodev2.h. Normally the video_usercopy function will copy anything pointed to by pointers into kernel space, so having __user in the struct will only cause lots of warnings in the drivers. But the flip side of that is that you need to add __force casts here. drivers/media/v4l2-core/v4l2-compat-ioctl32.c:337:26: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:337:30: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:338:31: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:338:49: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:343:21: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:346:21: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:349:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:349:46: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:352:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:352:54: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:363:26: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:363:32: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:364:31: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:364:51: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:371:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:371:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:376:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:376:48: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:430:30: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:433:48: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:433:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:501:24: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:507:48: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:507:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:565:18: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:670:22: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:680:29: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:692:55: warning: incorrect type in initializer (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:773:18: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:786:30: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:786:44: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:674:37: warning: dereference of noderef expression drivers/media/v4l2-core/v4l2-compat-ioctl32.c:718:37: warning: dereference of noderef expression Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-08-22 04:07:21 +08:00
if (get_user(id, &kcontrols->id))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (ctrl_is_pointer(file, id)) {
void __user *s;
if (get_user(p, &ucontrols->string))
return -EFAULT;
s = compat_ptr(p);
if (put_user(s, &kcontrols->string))
return -EFAULT;
}
ucontrols++;
kcontrols++;
}
return 0;
}
static int put_v4l2_ext_controls32(struct file *file,
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
struct v4l2_ext_controls __user *kp,
struct v4l2_ext_controls32 __user *up)
{
struct v4l2_ext_control32 __user *ucontrols;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
struct v4l2_ext_control __user *kcontrols;
u32 count;
u32 n;
compat_caddr_t p;
if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
assign_in_user(&up->which, &kp->which) ||
get_user(count, &kp->count) ||
put_user(count, &up->count) ||
assign_in_user(&up->error_idx, &kp->error_idx) ||
copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)) ||
get_user(kcontrols, &kp->controls))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (!count)
return 0;
if (get_user(p, &up->controls))
return -EFAULT;
ucontrols = compat_ptr(p);
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (!access_ok(VERIFY_WRITE, ucontrols, count * sizeof(*ucontrols)))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
for (n = 0; n < count; n++) {
unsigned int size = sizeof(*ucontrols);
[media] v4l2-compat-ioctl32: fix sparse warnings A lot of these warnings are caused by the fact that we don't generally use __user in videodev2.h. Normally the video_usercopy function will copy anything pointed to by pointers into kernel space, so having __user in the struct will only cause lots of warnings in the drivers. But the flip side of that is that you need to add __force casts here. drivers/media/v4l2-core/v4l2-compat-ioctl32.c:337:26: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:337:30: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:338:31: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:338:49: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:343:21: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:346:21: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:349:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:349:46: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:352:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:352:54: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:363:26: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:363:32: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:364:31: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:364:51: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:371:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:371:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:376:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:376:48: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:430:30: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:433:48: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:433:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:501:24: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:507:48: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:507:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:565:18: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:670:22: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:680:29: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:692:55: warning: incorrect type in initializer (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:773:18: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:786:30: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:786:44: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:674:37: warning: dereference of noderef expression drivers/media/v4l2-core/v4l2-compat-ioctl32.c:718:37: warning: dereference of noderef expression Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-08-22 04:07:21 +08:00
u32 id;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (get_user(id, &kcontrols->id) ||
put_user(id, &ucontrols->id) ||
assign_in_user(&ucontrols->size, &kcontrols->size) ||
copy_in_user(&ucontrols->reserved2, &kcontrols->reserved2,
sizeof(ucontrols->reserved2)))
[media] v4l2-compat-ioctl32: fix sparse warnings A lot of these warnings are caused by the fact that we don't generally use __user in videodev2.h. Normally the video_usercopy function will copy anything pointed to by pointers into kernel space, so having __user in the struct will only cause lots of warnings in the drivers. But the flip side of that is that you need to add __force casts here. drivers/media/v4l2-core/v4l2-compat-ioctl32.c:337:26: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:337:30: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:338:31: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:338:49: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:343:21: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:346:21: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:349:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:349:46: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:352:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:352:54: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:363:26: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:363:32: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:364:31: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:364:51: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:371:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:371:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:376:35: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:376:48: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:430:30: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:433:48: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:433:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:501:24: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:507:48: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:507:56: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:565:18: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:670:22: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:680:29: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:692:55: warning: incorrect type in initializer (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:773:18: warning: incorrect type in assignment (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:786:30: warning: incorrect type in argument 1 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:786:44: warning: incorrect type in argument 2 (different address spaces) drivers/media/v4l2-core/v4l2-compat-ioctl32.c:674:37: warning: dereference of noderef expression drivers/media/v4l2-core/v4l2-compat-ioctl32.c:718:37: warning: dereference of noderef expression Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2014-08-22 04:07:21 +08:00
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
/*
* Do not modify the pointer when copying a pointer control.
* The contents of the pointer was changed, not the pointer
* itself.
*/
if (ctrl_is_pointer(file, id))
size -= sizeof(ucontrols->value64);
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (copy_in_user(ucontrols, kcontrols, size))
return -EFAULT;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
ucontrols++;
kcontrols++;
}
return 0;
}
struct v4l2_event32 {
__u32 type;
union {
compat_s64 value64;
__u8 data[64];
} u;
__u32 pending;
__u32 sequence;
struct compat_timespec timestamp;
__u32 id;
__u32 reserved[8];
};
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int put_v4l2_event32(struct v4l2_event __user *kp,
struct v4l2_event32 __user *up)
{
if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
assign_in_user(&up->type, &kp->type) ||
copy_in_user(&up->u, &kp->u, sizeof(kp->u)) ||
assign_in_user(&up->pending, &kp->pending) ||
assign_in_user(&up->sequence, &kp->sequence) ||
assign_in_user(&up->timestamp.tv_sec, &kp->timestamp.tv_sec) ||
assign_in_user(&up->timestamp.tv_nsec, &kp->timestamp.tv_nsec) ||
assign_in_user(&up->id, &kp->id) ||
copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
return -EFAULT;
return 0;
}
struct v4l2_edid32 {
__u32 pad;
__u32 start_block;
__u32 blocks;
__u32 reserved[5];
compat_caddr_t edid;
};
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int get_v4l2_edid32(struct v4l2_edid __user *kp,
struct v4l2_edid32 __user *up)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
compat_uptr_t tmp;
if (!access_ok(VERIFY_READ, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
assign_in_user(&kp->pad, &up->pad) ||
assign_in_user(&kp->start_block, &up->start_block) ||
assign_in_user(&kp->blocks, &up->blocks) ||
get_user(tmp, &up->edid) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
put_user(compat_ptr(tmp), &kp->edid) ||
copy_in_user(kp->reserved, up->reserved, sizeof(kp->reserved)))
return -EFAULT;
return 0;
}
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int put_v4l2_edid32(struct v4l2_edid __user *kp,
struct v4l2_edid32 __user *up)
{
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
void *edid;
if (!access_ok(VERIFY_WRITE, up, sizeof(*up)) ||
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
assign_in_user(&up->pad, &kp->pad) ||
assign_in_user(&up->start_block, &kp->start_block) ||
assign_in_user(&up->blocks, &kp->blocks) ||
get_user(edid, &kp->edid) ||
put_user(ptr_to_compat(edid), &up->edid) ||
copy_in_user(up->reserved, kp->reserved, sizeof(up->reserved)))
return -EFAULT;
return 0;
}
#define VIDIOC_G_FMT32 _IOWR('V', 4, struct v4l2_format32)
#define VIDIOC_S_FMT32 _IOWR('V', 5, struct v4l2_format32)
#define VIDIOC_QUERYBUF32 _IOWR('V', 9, struct v4l2_buffer32)
#define VIDIOC_G_FBUF32 _IOR ('V', 10, struct v4l2_framebuffer32)
#define VIDIOC_S_FBUF32 _IOW ('V', 11, struct v4l2_framebuffer32)
#define VIDIOC_QBUF32 _IOWR('V', 15, struct v4l2_buffer32)
#define VIDIOC_DQBUF32 _IOWR('V', 17, struct v4l2_buffer32)
#define VIDIOC_ENUMSTD32 _IOWR('V', 25, struct v4l2_standard32)
#define VIDIOC_ENUMINPUT32 _IOWR('V', 26, struct v4l2_input32)
#define VIDIOC_G_EDID32 _IOWR('V', 40, struct v4l2_edid32)
#define VIDIOC_S_EDID32 _IOWR('V', 41, struct v4l2_edid32)
#define VIDIOC_TRY_FMT32 _IOWR('V', 64, struct v4l2_format32)
#define VIDIOC_G_EXT_CTRLS32 _IOWR('V', 71, struct v4l2_ext_controls32)
#define VIDIOC_S_EXT_CTRLS32 _IOWR('V', 72, struct v4l2_ext_controls32)
#define VIDIOC_TRY_EXT_CTRLS32 _IOWR('V', 73, struct v4l2_ext_controls32)
#define VIDIOC_DQEVENT32 _IOR ('V', 89, struct v4l2_event32)
#define VIDIOC_CREATE_BUFS32 _IOWR('V', 92, struct v4l2_create_buffers32)
#define VIDIOC_PREPARE_BUF32 _IOWR('V', 93, struct v4l2_buffer32)
#define VIDIOC_OVERLAY32 _IOW ('V', 14, s32)
#define VIDIOC_STREAMON32 _IOW ('V', 18, s32)
#define VIDIOC_STREAMOFF32 _IOW ('V', 19, s32)
#define VIDIOC_G_INPUT32 _IOR ('V', 38, s32)
#define VIDIOC_S_INPUT32 _IOWR('V', 39, s32)
#define VIDIOC_G_OUTPUT32 _IOR ('V', 46, s32)
#define VIDIOC_S_OUTPUT32 _IOWR('V', 47, s32)
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
static int alloc_userspace(unsigned int size, u32 aux_space,
void __user **up_native)
{
*up_native = compat_alloc_user_space(size + aux_space);
if (!*up_native)
return -ENOMEM;
if (clear_user(*up_native, size))
return -EFAULT;
return 0;
}
static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
void __user *up = compat_ptr(arg);
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
void __user *up_native = NULL;
void __user *aux_buf;
u32 aux_space;
int compatible_arg = 1;
long err = 0;
/* First, convert the command. */
switch (cmd) {
case VIDIOC_G_FMT32: cmd = VIDIOC_G_FMT; break;
case VIDIOC_S_FMT32: cmd = VIDIOC_S_FMT; break;
case VIDIOC_QUERYBUF32: cmd = VIDIOC_QUERYBUF; break;
case VIDIOC_G_FBUF32: cmd = VIDIOC_G_FBUF; break;
case VIDIOC_S_FBUF32: cmd = VIDIOC_S_FBUF; break;
case VIDIOC_QBUF32: cmd = VIDIOC_QBUF; break;
case VIDIOC_DQBUF32: cmd = VIDIOC_DQBUF; break;
case VIDIOC_ENUMSTD32: cmd = VIDIOC_ENUMSTD; break;
case VIDIOC_ENUMINPUT32: cmd = VIDIOC_ENUMINPUT; break;
case VIDIOC_TRY_FMT32: cmd = VIDIOC_TRY_FMT; break;
case VIDIOC_G_EXT_CTRLS32: cmd = VIDIOC_G_EXT_CTRLS; break;
case VIDIOC_S_EXT_CTRLS32: cmd = VIDIOC_S_EXT_CTRLS; break;
case VIDIOC_TRY_EXT_CTRLS32: cmd = VIDIOC_TRY_EXT_CTRLS; break;
case VIDIOC_DQEVENT32: cmd = VIDIOC_DQEVENT; break;
case VIDIOC_OVERLAY32: cmd = VIDIOC_OVERLAY; break;
case VIDIOC_STREAMON32: cmd = VIDIOC_STREAMON; break;
case VIDIOC_STREAMOFF32: cmd = VIDIOC_STREAMOFF; break;
case VIDIOC_G_INPUT32: cmd = VIDIOC_G_INPUT; break;
case VIDIOC_S_INPUT32: cmd = VIDIOC_S_INPUT; break;
case VIDIOC_G_OUTPUT32: cmd = VIDIOC_G_OUTPUT; break;
case VIDIOC_S_OUTPUT32: cmd = VIDIOC_S_OUTPUT; break;
case VIDIOC_CREATE_BUFS32: cmd = VIDIOC_CREATE_BUFS; break;
case VIDIOC_PREPARE_BUF32: cmd = VIDIOC_PREPARE_BUF; break;
case VIDIOC_G_EDID32: cmd = VIDIOC_G_EDID; break;
case VIDIOC_S_EDID32: cmd = VIDIOC_S_EDID; break;
}
switch (cmd) {
case VIDIOC_OVERLAY:
case VIDIOC_STREAMON:
case VIDIOC_STREAMOFF:
case VIDIOC_S_INPUT:
case VIDIOC_S_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = alloc_userspace(sizeof(unsigned int), 0, &up_native);
if (!err && assign_in_user((unsigned int __user *)up_native,
(compat_uint_t __user *)up))
err = -EFAULT;
compatible_arg = 0;
break;
case VIDIOC_G_INPUT:
case VIDIOC_G_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = alloc_userspace(sizeof(unsigned int), 0, &up_native);
compatible_arg = 0;
break;
case VIDIOC_G_EDID:
case VIDIOC_S_EDID:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = alloc_userspace(sizeof(struct v4l2_edid), 0, &up_native);
if (!err)
err = get_v4l2_edid32(up_native, up);
compatible_arg = 0;
break;
case VIDIOC_G_FMT:
case VIDIOC_S_FMT:
case VIDIOC_TRY_FMT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = bufsize_v4l2_format(up, &aux_space);
if (!err)
err = alloc_userspace(sizeof(struct v4l2_format),
aux_space, &up_native);
if (!err) {
aux_buf = up_native + sizeof(struct v4l2_format);
err = get_v4l2_format32(up_native, up,
aux_buf, aux_space);
}
compatible_arg = 0;
break;
case VIDIOC_CREATE_BUFS:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = bufsize_v4l2_create(up, &aux_space);
if (!err)
err = alloc_userspace(sizeof(struct v4l2_create_buffers),
aux_space, &up_native);
if (!err) {
aux_buf = up_native + sizeof(struct v4l2_create_buffers);
err = get_v4l2_create32(up_native, up,
aux_buf, aux_space);
}
compatible_arg = 0;
break;
case VIDIOC_PREPARE_BUF:
case VIDIOC_QUERYBUF:
case VIDIOC_QBUF:
case VIDIOC_DQBUF:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = bufsize_v4l2_buffer(up, &aux_space);
if (!err)
err = alloc_userspace(sizeof(struct v4l2_buffer),
aux_space, &up_native);
if (!err) {
aux_buf = up_native + sizeof(struct v4l2_buffer);
err = get_v4l2_buffer32(up_native, up,
aux_buf, aux_space);
}
compatible_arg = 0;
break;
case VIDIOC_S_FBUF:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = alloc_userspace(sizeof(struct v4l2_framebuffer), 0,
&up_native);
if (!err)
err = get_v4l2_framebuffer32(up_native, up);
compatible_arg = 0;
break;
case VIDIOC_G_FBUF:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = alloc_userspace(sizeof(struct v4l2_framebuffer), 0,
&up_native);
compatible_arg = 0;
break;
case VIDIOC_ENUMSTD:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = alloc_userspace(sizeof(struct v4l2_standard), 0,
&up_native);
if (!err)
err = get_v4l2_standard32(up_native, up);
compatible_arg = 0;
break;
case VIDIOC_ENUMINPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = alloc_userspace(sizeof(struct v4l2_input), 0, &up_native);
if (!err)
err = get_v4l2_input32(up_native, up);
compatible_arg = 0;
break;
case VIDIOC_G_EXT_CTRLS:
case VIDIOC_S_EXT_CTRLS:
case VIDIOC_TRY_EXT_CTRLS:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = bufsize_v4l2_ext_controls(up, &aux_space);
if (!err)
err = alloc_userspace(sizeof(struct v4l2_ext_controls),
aux_space, &up_native);
if (!err) {
aux_buf = up_native + sizeof(struct v4l2_ext_controls);
err = get_v4l2_ext_controls32(file, up_native, up,
aux_buf, aux_space);
}
compatible_arg = 0;
break;
case VIDIOC_DQEVENT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = alloc_userspace(sizeof(struct v4l2_event), 0, &up_native);
compatible_arg = 0;
break;
}
if (err)
return err;
if (compatible_arg)
err = native_ioctl(file, cmd, (unsigned long)up);
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
else
err = native_ioctl(file, cmd, (unsigned long)up_native);
if (err == -ENOTTY)
return err;
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
/*
* Special case: even after an error we need to put the
* results back for these ioctls since the error_idx will
* contain information on which control failed.
*/
switch (cmd) {
case VIDIOC_G_EXT_CTRLS:
case VIDIOC_S_EXT_CTRLS:
case VIDIOC_TRY_EXT_CTRLS:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (put_v4l2_ext_controls32(file, up_native, up))
err = -EFAULT;
break;
case VIDIOC_S_EDID:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (put_v4l2_edid32(up_native, up))
err = -EFAULT;
break;
}
if (err)
return err;
switch (cmd) {
case VIDIOC_S_INPUT:
case VIDIOC_S_OUTPUT:
case VIDIOC_G_INPUT:
case VIDIOC_G_OUTPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
if (assign_in_user((compat_uint_t __user *)up,
((unsigned int __user *)up_native)))
err = -EFAULT;
break;
case VIDIOC_G_FBUF:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = put_v4l2_framebuffer32(up_native, up);
break;
case VIDIOC_DQEVENT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = put_v4l2_event32(up_native, up);
break;
case VIDIOC_G_EDID:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = put_v4l2_edid32(up_native, up);
break;
case VIDIOC_G_FMT:
case VIDIOC_S_FMT:
case VIDIOC_TRY_FMT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = put_v4l2_format32(up_native, up);
break;
case VIDIOC_CREATE_BUFS:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = put_v4l2_create32(up_native, up);
break;
case VIDIOC_PREPARE_BUF:
case VIDIOC_QUERYBUF:
case VIDIOC_QBUF:
case VIDIOC_DQBUF:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = put_v4l2_buffer32(up_native, up);
break;
case VIDIOC_ENUMSTD:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = put_v4l2_standard32(up_native, up);
break;
case VIDIOC_ENUMINPUT:
media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic The 32-bit compat v4l2 ioctl handling is implemented based on its 64-bit equivalent. It converts 32-bit data structures into its 64-bit equivalents and needs to provide the data to the 64-bit ioctl in user space memory which is commonly allocated using compat_alloc_user_space(). However, due to how that function is implemented, it can only be called a single time for every syscall invocation. Supposedly to avoid this limitation, the existing code uses a mix of memory from the kernel stack and memory allocated through compat_alloc_user_space(). Under normal circumstances, this would not work, because the 64-bit ioctl expects all pointers to point to user space memory. As a workaround, set_fs(KERNEL_DS) is called to temporarily disable this extra safety check and allow kernel pointers. However, this might introduce a security vulnerability: The result of the 32-bit to 64-bit conversion is writeable by user space because the output buffer has been allocated via compat_alloc_user_space(). A malicious user space process could then manipulate pointers inside this output buffer, and due to the previous set_fs(KERNEL_DS) call, functions like get_user() or put_user() no longer prevent kernel memory access. The new approach is to pre-calculate the total amount of user space memory that is needed, allocate it using compat_alloc_user_space() and then divide up the allocated memory to accommodate all data structures that need to be converted. An alternative approach would have been to retain the union type karg that they allocated on the kernel stack in do_video_ioctl(), copy all data from user space into karg and then back to user space. However, we decided against this approach because it does not align with other compat syscall implementations. Instead, we tried to replicate the get_user/put_user pairs as found in other places in the kernel: if (get_user(clipcount, &up->clipcount) || put_user(clipcount, &kp->clipcount)) return -EFAULT; Notes from hans.verkuil@cisco.com: This patch was taken from: https://github.com/LineageOS/android_kernel_samsung_apq8084/commit/97b733953c06e4f0398ade18850f0817778255f7 Clearly nobody could be bothered to upstream this patch or at minimum tell us :-( We only heard about this a week ago. This patch was rebased and cleaned up. Compared to the original I also swapped the order of the convert_in_user arguments so that they matched copy_in_user. It was hard to review otherwise. I also replaced the ALLOC_USER_SPACE/ALLOC_AND_GET by a normal function. Fixes: 6b5a9492ca ("v4l: introduce string control support.") Signed-off-by: Daniel Mentz <danielmentz@google.com> Co-developed-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Cc: <stable@vger.kernel.org> # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-07-20 07:03:19 +08:00
err = put_v4l2_input32(up_native, up);
break;
}
return err;
}
long v4l2_compat_ioctl32(struct file *file, unsigned int cmd, unsigned long arg)
{
struct video_device *vdev = video_devdata(file);
long ret = -ENOIOCTLCMD;
if (!file->f_op->unlocked_ioctl)
return ret;
if (_IOC_TYPE(cmd) == 'V' && _IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
ret = do_video_ioctl(file, cmd, arg);
else if (vdev->fops->compat_ioctl32)
ret = vdev->fops->compat_ioctl32(file, cmd, arg);
if (ret == -ENOIOCTLCMD)
pr_debug("compat_ioctl32: unknown ioctl '%c', dir=%d, #%d (0x%08x)\n",
_IOC_TYPE(cmd), _IOC_DIR(cmd), _IOC_NR(cmd), cmd);
return ret;
}
EXPORT_SYMBOL_GPL(v4l2_compat_ioctl32);