| Message ID | aaa1b65bf2b6c1a2da79b44fe7ada63f697ac32e.1624281807.git.mchehab+huawei@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] media: uvc: don't do DMA on stack | expand |
Hi Mauro, Thank you for the patch. On Mon, Jun 21, 2021 at 03:23:35PM +0200, Mauro Carvalho Chehab wrote: > 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 temporary buffer, allocated together with > struct uvc_video_chain. The second part of the sentence isn't correct anymore. > Cc: stable@vger.kernel.org # Kernel 4.9 and upper > Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> > --- > drivers/media/usb/uvc/uvc_v4l2.c | 26 ++++++++++++++++++-------- > 1 file changed, 18 insertions(+), 8 deletions(-) > > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c > index 252136cc885c..d680ae8a5f87 100644 > --- a/drivers/media/usb/uvc/uvc_v4l2.c > +++ b/drivers/media/usb/uvc/uvc_v4l2.c > @@ -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; > + char *buf; I'd make this u8 *buf; as the selector value is unsigned. > int ret; > - u8 i; > > if (chain->selector == NULL || > (chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) { > @@ -908,13 +908,18 @@ static int uvc_ioctl_g_input(struct file *file, void *fh, unsigned int *input) > return 0; > } > > + buf = kmalloc(1, GFP_KERNEL); MIssing error check. > + > ret = uvc_query_ctrl(chain->dev, UVC_GET_CUR, chain->selector->id, > chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, > - &i, 1); > + buf, 1); > if (ret < 0) > return ret; > > - *input = i - 1; > + *input = *buf; > + > + kfree(buf); > + > return 0; > } > > @@ -922,8 +927,8 @@ 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; > + char *buf; u8 * here too. > int ret; > - u32 i; > > ret = uvc_acquire_privileges(handle); > if (ret < 0) > @@ -939,10 +944,15 @@ 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, > - chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, > - &i, 1); > + buf = kmalloc(1, GFP_KERNEL); And missing error check. > + > + *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,
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c index 252136cc885c..d680ae8a5f87 100644 --- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -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; + char *buf; int ret; - u8 i; if (chain->selector == NULL || (chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) { @@ -908,13 +908,18 @@ static int uvc_ioctl_g_input(struct file *file, void *fh, unsigned int *input) return 0; } + buf = kmalloc(1, GFP_KERNEL); + ret = uvc_query_ctrl(chain->dev, UVC_GET_CUR, chain->selector->id, chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, - &i, 1); + buf, 1); if (ret < 0) return ret; - *input = i - 1; + *input = *buf; + + kfree(buf); + return 0; } @@ -922,8 +927,8 @@ 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; + char *buf; int ret; - u32 i; ret = uvc_acquire_privileges(handle); if (ret < 0) @@ -939,10 +944,15 @@ 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, - chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, - &i, 1); + buf = kmalloc(1, GFP_KERNEL); + + *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,
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 temporary buffer, allocated together with struct uvc_video_chain. Cc: stable@vger.kernel.org # Kernel 4.9 and upper Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> --- drivers/media/usb/uvc/uvc_v4l2.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-)