[media] Guard a divide in v4l1 compat layer

Hi,
  I managed to trigger a divide by 0 in the v4l compat code
with the mem2mem test module; I suspect perhaps it shouldn't
have been returning a 0 pixel wide picture, but either way it seems
right to guard this divide by 0 in the compatibility layer.

Tested on 2.6.36 (ubuntu build, but the code in this is the same as upstream),
but ***not tested with a real video device***.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
cc: stable.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/drivers/media/video/v4l1-compat.c b/drivers/media/video/v4l1-compat.c
index 0c2105ca611e..d4ac751036a2 100644
--- a/drivers/media/video/v4l1-compat.c
+++ b/drivers/media/video/v4l1-compat.c
@@ -645,9 +645,16 @@ static noinline long v4l1_compat_get_picture(
                 goto done;
         }
 
-        pict->depth   = ((fmt->fmt.pix.bytesperline << 3)
-                         + (fmt->fmt.pix.width - 1))
-                         / fmt->fmt.pix.width;
+        if (fmt->fmt.pix.width)
+        {
+                pict->depth   = ((fmt->fmt.pix.bytesperline << 3)
+                                 + (fmt->fmt.pix.width - 1))
+                                 / fmt->fmt.pix.width;
+        } else {
+                err = -EINVAL;
+                goto done;
+        }
+
         pict->palette = pixelformat_to_palette(
                 fmt->fmt.pix.pixelformat);
 done: