On Tue, Jan 7, 2020 at 3:02 PM Colin King <colin.king@xxxxxxxxxxxxx> wrote:
>
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> In the case where v4l2_event_dequeue fails the structure ev is not
> being filled and this garbage data from the stack is being copied
> to the ev32 structure and being copied back to userspace on the
> VIDIOC_DQEVENT_TIME32 ioctl. Fix this by ensuring the ev structure
> is zero'd to ensure uninitialized data is not leaked back.
>
> Addresses-Coverity: ("Uninitialized scalar variable")
> Fixes: 1a6c0b36dd19 ("media: v4l2-core: fix VIDIOC_DQEVENT for time64 ABI")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Good catch, thanks for fixing!
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-subdev.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index de926e311348..a376b351135f 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -394,7 +394,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>
> case VIDIOC_DQEVENT_TIME32: {
> struct v4l2_event_time32 *ev32 = arg;
> - struct v4l2_event ev;
> + struct v4l2_event ev = { };
>
> if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS))
> return -ENOIOCTLCMD;
> --
> 2.24.0
>
