From: Mauro Carvalho Chehab mchehab+huawei@kernel.org
commit 1a10d7fdb6d0e235e9d230916244cc2769d3f170 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/media/usb/uvc/uvc_v4l2.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-)
--- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -876,8 +876,8 @@ static int uvc_ioctl_g_input(struct file { 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)) { @@ -885,22 +885,27 @@ static int uvc_ioctl_g_input(struct file 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) @@ -916,10 +921,17 @@ static int uvc_ioctl_s_input(struct file if (input >= chain->selector->bNrInPins) return -EINVAL;
- i = input + 1; - return uvc_query_ctrl(chain->dev, UVC_SET_CUR, chain->selector->id, - chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, - &i, 1); + 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, + buf, 1); + kfree(buf); + + return ret; }
static int uvc_ioctl_queryctrl(struct file *file, void *fh,