iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c
This lets the compiler inline it into import_iovec() generating much better code. Signed-off-by: David Laight <david.laight@aculab.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
David Laight
Al Viro
parent
576d0703a8
commit
fb041b5989
179
fs/read_write.c
179
fs/read_write.c
|
|
@ -752,185 +752,6 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
|
||||||
return ret;
|
return ret;
|
||||||
}
|
}
|
||||||
|
|
||||||
/**
|
|
||||||
* rw_copy_check_uvector() - Copy an array of &struct iovec from userspace
|
|
||||||
* into the kernel and check that it is valid.
|
|
||||||
*
|
|
||||||
* @type: One of %CHECK_IOVEC_ONLY, %READ, or %WRITE.
|
|
||||||
* @uvector: Pointer to the userspace array.
|
|
||||||
* @nr_segs: Number of elements in userspace array.
|
|
||||||
* @fast_segs: Number of elements in @fast_pointer.
|
|
||||||
* @fast_pointer: Pointer to (usually small on-stack) kernel array.
|
|
||||||
* @ret_pointer: (output parameter) Pointer to a variable that will point to
|
|
||||||
* either @fast_pointer, a newly allocated kernel array, or NULL,
|
|
||||||
* depending on which array was used.
|
|
||||||
*
|
|
||||||
* This function copies an array of &struct iovec of @nr_segs from
|
|
||||||
* userspace into the kernel and checks that each element is valid (e.g.
|
|
||||||
* it does not point to a kernel address or cause overflow by being too
|
|
||||||
* large, etc.).
|
|
||||||
*
|
|
||||||
* As an optimization, the caller may provide a pointer to a small
|
|
||||||
* on-stack array in @fast_pointer, typically %UIO_FASTIOV elements long
|
|
||||||
* (the size of this array, or 0 if unused, should be given in @fast_segs).
|
|
||||||
*
|
|
||||||
* @ret_pointer will always point to the array that was used, so the
|
|
||||||
* caller must take care not to call kfree() on it e.g. in case the
|
|
||||||
* @fast_pointer array was used and it was allocated on the stack.
|
|
||||||
*
|
|
||||||
* Return: The total number of bytes covered by the iovec array on success
|
|
||||||
* or a negative error code on error.
|
|
||||||
*/
|
|
||||||
ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
|
|
||||||
unsigned long nr_segs, unsigned long fast_segs,
|
|
||||||
struct iovec *fast_pointer,
|
|
||||||
struct iovec **ret_pointer)
|
|
||||||
{
|
|
||||||
unsigned long seg;
|
|
||||||
ssize_t ret;
|
|
||||||
struct iovec *iov = fast_pointer;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* SuS says "The readv() function *may* fail if the iovcnt argument
|
|
||||||
* was less than or equal to 0, or greater than {IOV_MAX}. Linux has
|
|
||||||
* traditionally returned zero for zero segments, so...
|
|
||||||
*/
|
|
||||||
if (nr_segs == 0) {
|
|
||||||
ret = 0;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
|
|
||||||
/*
|
|
||||||
* First get the "struct iovec" from user memory and
|
|
||||||
* verify all the pointers
|
|
||||||
*/
|
|
||||||
if (nr_segs > UIO_MAXIOV) {
|
|
||||||
ret = -EINVAL;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
if (nr_segs > fast_segs) {
|
|
||||||
iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL);
|
|
||||||
if (iov == NULL) {
|
|
||||||
ret = -ENOMEM;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
}
|
|
||||||
if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
|
|
||||||
ret = -EFAULT;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
|
|
||||||
/*
|
|
||||||
* According to the Single Unix Specification we should return EINVAL
|
|
||||||
* if an element length is < 0 when cast to ssize_t or if the
|
|
||||||
* total length would overflow the ssize_t return value of the
|
|
||||||
* system call.
|
|
||||||
*
|
|
||||||
* Linux caps all read/write calls to MAX_RW_COUNT, and avoids the
|
|
||||||
* overflow case.
|
|
||||||
*/
|
|
||||||
ret = 0;
|
|
||||||
for (seg = 0; seg < nr_segs; seg++) {
|
|
||||||
void __user *buf = iov[seg].iov_base;
|
|
||||||
ssize_t len = (ssize_t)iov[seg].iov_len;
|
|
||||||
|
|
||||||
/* see if we we're about to use an invalid len or if
|
|
||||||
* it's about to overflow ssize_t */
|
|
||||||
if (len < 0) {
|
|
||||||
ret = -EINVAL;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
if (type >= 0
|
|
||||||
&& unlikely(!access_ok(buf, len))) {
|
|
||||||
ret = -EFAULT;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
if (len > MAX_RW_COUNT - ret) {
|
|
||||||
len = MAX_RW_COUNT - ret;
|
|
||||||
iov[seg].iov_len = len;
|
|
||||||
}
|
|
||||||
ret += len;
|
|
||||||
}
|
|
||||||
out:
|
|
||||||
*ret_pointer = iov;
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
|
|
||||||
#ifdef CONFIG_COMPAT
|
|
||||||
ssize_t compat_rw_copy_check_uvector(int type,
|
|
||||||
const struct compat_iovec __user *uvector, unsigned long nr_segs,
|
|
||||||
unsigned long fast_segs, struct iovec *fast_pointer,
|
|
||||||
struct iovec **ret_pointer)
|
|
||||||
{
|
|
||||||
compat_ssize_t tot_len;
|
|
||||||
struct iovec *iov = *ret_pointer = fast_pointer;
|
|
||||||
ssize_t ret = 0;
|
|
||||||
int seg;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* SuS says "The readv() function *may* fail if the iovcnt argument
|
|
||||||
* was less than or equal to 0, or greater than {IOV_MAX}. Linux has
|
|
||||||
* traditionally returned zero for zero segments, so...
|
|
||||||
*/
|
|
||||||
if (nr_segs == 0)
|
|
||||||
goto out;
|
|
||||||
|
|
||||||
ret = -EINVAL;
|
|
||||||
if (nr_segs > UIO_MAXIOV)
|
|
||||||
goto out;
|
|
||||||
if (nr_segs > fast_segs) {
|
|
||||||
ret = -ENOMEM;
|
|
||||||
iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL);
|
|
||||||
if (iov == NULL)
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
*ret_pointer = iov;
|
|
||||||
|
|
||||||
ret = -EFAULT;
|
|
||||||
if (!access_ok(uvector, nr_segs*sizeof(*uvector)))
|
|
||||||
goto out;
|
|
||||||
|
|
||||||
/*
|
|
||||||
* Single unix specification:
|
|
||||||
* We should -EINVAL if an element length is not >= 0 and fitting an
|
|
||||||
* ssize_t.
|
|
||||||
*
|
|
||||||
* In Linux, the total length is limited to MAX_RW_COUNT, there is
|
|
||||||
* no overflow possibility.
|
|
||||||
*/
|
|
||||||
tot_len = 0;
|
|
||||||
ret = -EINVAL;
|
|
||||||
for (seg = 0; seg < nr_segs; seg++) {
|
|
||||||
compat_uptr_t buf;
|
|
||||||
compat_ssize_t len;
|
|
||||||
|
|
||||||
if (__get_user(len, &uvector->iov_len) ||
|
|
||||||
__get_user(buf, &uvector->iov_base)) {
|
|
||||||
ret = -EFAULT;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
if (len < 0) /* size_t not fitting in compat_ssize_t .. */
|
|
||||||
goto out;
|
|
||||||
if (type >= 0 &&
|
|
||||||
!access_ok(compat_ptr(buf), len)) {
|
|
||||||
ret = -EFAULT;
|
|
||||||
goto out;
|
|
||||||
}
|
|
||||||
if (len > MAX_RW_COUNT - tot_len)
|
|
||||||
len = MAX_RW_COUNT - tot_len;
|
|
||||||
tot_len += len;
|
|
||||||
iov->iov_base = compat_ptr(buf);
|
|
||||||
iov->iov_len = (compat_size_t) len;
|
|
||||||
uvector++;
|
|
||||||
iov++;
|
|
||||||
}
|
|
||||||
ret = tot_len;
|
|
||||||
|
|
||||||
out:
|
|
||||||
return ret;
|
|
||||||
}
|
|
||||||
#endif
|
|
||||||
|
|
||||||
static ssize_t do_iter_read(struct file *file, struct iov_iter *iter,
|
static ssize_t do_iter_read(struct file *file, struct iov_iter *iter,
|
||||||
loff_t *pos, rwf_t flags)
|
loff_t *pos, rwf_t flags)
|
||||||
{
|
{
|
||||||
|
|
|
||||||
176
lib/iov_iter.c
176
lib/iov_iter.c
|
|
@ -1650,6 +1650,109 @@ const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
|
||||||
}
|
}
|
||||||
EXPORT_SYMBOL(dup_iter);
|
EXPORT_SYMBOL(dup_iter);
|
||||||
|
|
||||||
|
/**
|
||||||
|
* rw_copy_check_uvector() - Copy an array of &struct iovec from userspace
|
||||||
|
* into the kernel and check that it is valid.
|
||||||
|
*
|
||||||
|
* @type: One of %CHECK_IOVEC_ONLY, %READ, or %WRITE.
|
||||||
|
* @uvector: Pointer to the userspace array.
|
||||||
|
* @nr_segs: Number of elements in userspace array.
|
||||||
|
* @fast_segs: Number of elements in @fast_pointer.
|
||||||
|
* @fast_pointer: Pointer to (usually small on-stack) kernel array.
|
||||||
|
* @ret_pointer: (output parameter) Pointer to a variable that will point to
|
||||||
|
* either @fast_pointer, a newly allocated kernel array, or NULL,
|
||||||
|
* depending on which array was used.
|
||||||
|
*
|
||||||
|
* This function copies an array of &struct iovec of @nr_segs from
|
||||||
|
* userspace into the kernel and checks that each element is valid (e.g.
|
||||||
|
* it does not point to a kernel address or cause overflow by being too
|
||||||
|
* large, etc.).
|
||||||
|
*
|
||||||
|
* As an optimization, the caller may provide a pointer to a small
|
||||||
|
* on-stack array in @fast_pointer, typically %UIO_FASTIOV elements long
|
||||||
|
* (the size of this array, or 0 if unused, should be given in @fast_segs).
|
||||||
|
*
|
||||||
|
* @ret_pointer will always point to the array that was used, so the
|
||||||
|
* caller must take care not to call kfree() on it e.g. in case the
|
||||||
|
* @fast_pointer array was used and it was allocated on the stack.
|
||||||
|
*
|
||||||
|
* Return: The total number of bytes covered by the iovec array on success
|
||||||
|
* or a negative error code on error.
|
||||||
|
*/
|
||||||
|
ssize_t rw_copy_check_uvector(int type, const struct iovec __user *uvector,
|
||||||
|
unsigned long nr_segs, unsigned long fast_segs,
|
||||||
|
struct iovec *fast_pointer, struct iovec **ret_pointer)
|
||||||
|
{
|
||||||
|
unsigned long seg;
|
||||||
|
ssize_t ret;
|
||||||
|
struct iovec *iov = fast_pointer;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* SuS says "The readv() function *may* fail if the iovcnt argument
|
||||||
|
* was less than or equal to 0, or greater than {IOV_MAX}. Linux has
|
||||||
|
* traditionally returned zero for zero segments, so...
|
||||||
|
*/
|
||||||
|
if (nr_segs == 0) {
|
||||||
|
ret = 0;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* First get the "struct iovec" from user memory and
|
||||||
|
* verify all the pointers
|
||||||
|
*/
|
||||||
|
if (nr_segs > UIO_MAXIOV) {
|
||||||
|
ret = -EINVAL;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
if (nr_segs > fast_segs) {
|
||||||
|
iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL);
|
||||||
|
if (iov == NULL) {
|
||||||
|
ret = -ENOMEM;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
|
||||||
|
ret = -EFAULT;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* According to the Single Unix Specification we should return EINVAL
|
||||||
|
* if an element length is < 0 when cast to ssize_t or if the
|
||||||
|
* total length would overflow the ssize_t return value of the
|
||||||
|
* system call.
|
||||||
|
*
|
||||||
|
* Linux caps all read/write calls to MAX_RW_COUNT, and avoids the
|
||||||
|
* overflow case.
|
||||||
|
*/
|
||||||
|
ret = 0;
|
||||||
|
for (seg = 0; seg < nr_segs; seg++) {
|
||||||
|
void __user *buf = iov[seg].iov_base;
|
||||||
|
ssize_t len = (ssize_t)iov[seg].iov_len;
|
||||||
|
|
||||||
|
/* see if we we're about to use an invalid len or if
|
||||||
|
* it's about to overflow ssize_t */
|
||||||
|
if (len < 0) {
|
||||||
|
ret = -EINVAL;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
if (type >= 0
|
||||||
|
&& unlikely(!access_ok(buf, len))) {
|
||||||
|
ret = -EFAULT;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
if (len > MAX_RW_COUNT - ret) {
|
||||||
|
len = MAX_RW_COUNT - ret;
|
||||||
|
iov[seg].iov_len = len;
|
||||||
|
}
|
||||||
|
ret += len;
|
||||||
|
}
|
||||||
|
out:
|
||||||
|
*ret_pointer = iov;
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
/**
|
/**
|
||||||
* import_iovec() - Copy an array of &struct iovec from userspace
|
* import_iovec() - Copy an array of &struct iovec from userspace
|
||||||
* into the kernel, check that it is valid, and initialize a new
|
* into the kernel, check that it is valid, and initialize a new
|
||||||
|
|
@ -1695,6 +1798,79 @@ EXPORT_SYMBOL(import_iovec);
|
||||||
#ifdef CONFIG_COMPAT
|
#ifdef CONFIG_COMPAT
|
||||||
#include <linux/compat.h>
|
#include <linux/compat.h>
|
||||||
|
|
||||||
|
ssize_t compat_rw_copy_check_uvector(int type,
|
||||||
|
const struct compat_iovec __user *uvector,
|
||||||
|
unsigned long nr_segs, unsigned long fast_segs,
|
||||||
|
struct iovec *fast_pointer, struct iovec **ret_pointer)
|
||||||
|
{
|
||||||
|
compat_ssize_t tot_len;
|
||||||
|
struct iovec *iov = *ret_pointer = fast_pointer;
|
||||||
|
ssize_t ret = 0;
|
||||||
|
int seg;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* SuS says "The readv() function *may* fail if the iovcnt argument
|
||||||
|
* was less than or equal to 0, or greater than {IOV_MAX}. Linux has
|
||||||
|
* traditionally returned zero for zero segments, so...
|
||||||
|
*/
|
||||||
|
if (nr_segs == 0)
|
||||||
|
goto out;
|
||||||
|
|
||||||
|
ret = -EINVAL;
|
||||||
|
if (nr_segs > UIO_MAXIOV)
|
||||||
|
goto out;
|
||||||
|
if (nr_segs > fast_segs) {
|
||||||
|
ret = -ENOMEM;
|
||||||
|
iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL);
|
||||||
|
if (iov == NULL)
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
*ret_pointer = iov;
|
||||||
|
|
||||||
|
ret = -EFAULT;
|
||||||
|
if (!access_ok(uvector, nr_segs*sizeof(*uvector)))
|
||||||
|
goto out;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Single unix specification:
|
||||||
|
* We should -EINVAL if an element length is not >= 0 and fitting an
|
||||||
|
* ssize_t.
|
||||||
|
*
|
||||||
|
* In Linux, the total length is limited to MAX_RW_COUNT, there is
|
||||||
|
* no overflow possibility.
|
||||||
|
*/
|
||||||
|
tot_len = 0;
|
||||||
|
ret = -EINVAL;
|
||||||
|
for (seg = 0; seg < nr_segs; seg++) {
|
||||||
|
compat_uptr_t buf;
|
||||||
|
compat_ssize_t len;
|
||||||
|
|
||||||
|
if (__get_user(len, &uvector->iov_len) ||
|
||||||
|
__get_user(buf, &uvector->iov_base)) {
|
||||||
|
ret = -EFAULT;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
if (len < 0) /* size_t not fitting in compat_ssize_t .. */
|
||||||
|
goto out;
|
||||||
|
if (type >= 0 &&
|
||||||
|
!access_ok(compat_ptr(buf), len)) {
|
||||||
|
ret = -EFAULT;
|
||||||
|
goto out;
|
||||||
|
}
|
||||||
|
if (len > MAX_RW_COUNT - tot_len)
|
||||||
|
len = MAX_RW_COUNT - tot_len;
|
||||||
|
tot_len += len;
|
||||||
|
iov->iov_base = compat_ptr(buf);
|
||||||
|
iov->iov_len = (compat_size_t) len;
|
||||||
|
uvector++;
|
||||||
|
iov++;
|
||||||
|
}
|
||||||
|
ret = tot_len;
|
||||||
|
|
||||||
|
out:
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
ssize_t compat_import_iovec(int type,
|
ssize_t compat_import_iovec(int type,
|
||||||
const struct compat_iovec __user * uvector,
|
const struct compat_iovec __user * uvector,
|
||||||
unsigned nr_segs, unsigned fast_segs,
|
unsigned nr_segs, unsigned fast_segs,
|
||||||
|
|
|
||||||
Loading…
Reference in New Issue