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media: uvc: don't do DMA on stack 

As warned by smatch:
	drivers/media/usb/uvc/uvc_v4l2.c:911 uvc_ioctl_g_input() error: doing dma on the stack (&i)
	drivers/media/usb/uvc/uvc_v4l2.c:943 uvc_ioctl_s_input() error: doing dma on the stack (&i)

those two functions call uvc_query_ctrl passing a pointer to
a data at the DMA stack. those are used to send URBs via
usb_control_msg(). Using DMA stack is not supported and should
not work anymore on modern Linux versions.

So, use a kmalloc'ed buffer.

Cc: stable@vger.kernel.org	# Kernel 4.9 and upper
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Mauro Carvalho Chehab 2021-06-17 14:33:29 +02:00
parent 54e80d9883
commit 1a10d7fdb6
1 changed files with 23 additions and 11 deletions
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32
drivers/media/usb/uvc/uvc_v4l2.c
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@ -899,8 +899,8 @@ static int uvc_ioctl_g_input(struct file *file, void *fh, unsigned int *input)
{
struct uvc_fh *handle = fh;
struct uvc_video_chain *chain = handle->chain;
u8 *buf;
int ret;
u8 i;
if (chain->selector == NULL ||
(chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) {
@ -908,22 +908,27 @@ static int uvc_ioctl_g_input(struct file *file, void *fh, unsigned int *input)
return 0;
}
buf = kmalloc(1, GFP_KERNEL);
if (!buf)
return -ENOMEM;
ret = uvc_query_ctrl(chain->dev, UVC_GET_CUR, chain->selector->id,
chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL,
&i, 1);
if (ret < 0)
return ret;
buf, 1);
if (!ret)
*input = *buf - 1;
*input = i - 1;
return 0;
kfree(buf);
return ret;
}
static int uvc_ioctl_s_input(struct file *file, void *fh, unsigned int input)
{
struct uvc_fh *handle = fh;
struct uvc_video_chain *chain = handle->chain;
u8 *buf;
int ret;
u32 i;
ret = uvc_acquire_privileges(handle);
if (ret < 0)
@ -939,10 +944,17 @@ static int uvc_ioctl_s_input(struct file *file, void *fh, unsigned int input)
if (input >= chain->selector->bNrInPins)
return -EINVAL;
i = input + 1;
return uvc_query_ctrl(chain->dev, UVC_SET_CUR, chain->selector->id,
buf = kmalloc(1, GFP_KERNEL);
if (!buf)
return -ENOMEM;
*buf = input + 1;
ret = uvc_query_ctrl(chain->dev, UVC_SET_CUR, chain->selector->id,
chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL,
&i, 1);
buf, 1);
kfree(buf);
return ret;
}
static int uvc_ioctl_queryctrl(struct file *file, void *fh,