Message ID | 1479211382-25403-1-git-send-email-luis.henriques@canonical.com |
---|---|
State | New |
Headers | show |
On 15/11/16 12:03, Luis Henriques wrote: > From: Sakari Ailus <sakari.ailus@linux.intel.com> > > When a buffer is being dequeued using VIDIOC_DQBUF IOCTL, the exact buffer > which will be dequeued is not known until the buffer has been removed from > the queue. The number of planes is specific to a buffer, not to the queue. > > This does lead to the situation where multi-plane buffers may be requested > and queued with n planes, but VIDIOC_DQBUF IOCTL may be passed an argument > struct with fewer planes. > > __fill_v4l2_buffer() however uses the number of planes from the dequeued > videobuf2 buffer, overwriting kernel memory (the m.planes array allocated > in video_usercopy() in v4l2-ioctl.c) if the user provided fewer > planes than the dequeued buffer had. Oops! > > Fixes: b0e0e1f83de3 ("[media] media: videobuf2: Prepare to divide videobuf2") > > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> > Acked-by: Hans Verkuil <hans.verkuil@cisco.com> > Cc: stable@vger.kernel.org # for v4.4 and later > Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com> > Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> > CVE-2016-4568 > (cherry picked from commit 83934b75c368f529d084815c463a7ef781dc9751) > Signed-off-by: Luis Henriques <luis.henriques@canonical.com> > --- > drivers/media/v4l2-core/videobuf2-v4l2.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c > index 502984c724ff..6c441be8f893 100644 > --- a/drivers/media/v4l2-core/videobuf2-v4l2.c > +++ b/drivers/media/v4l2-core/videobuf2-v4l2.c > @@ -67,6 +67,11 @@ static int __verify_planes_array(struct vb2_buffer *vb, const struct v4l2_buffer > return 0; > } > > +static int __verify_planes_array_core(struct vb2_buffer *vb, const void *pb) > +{ > + return __verify_planes_array(vb, pb); > +} > + > /** > * __verify_length() - Verify that the bytesused value for each plane fits in > * the plane length and that the data offset doesn't exceed the bytesused value. > @@ -432,6 +437,7 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb, > } > > static const struct vb2_buf_ops v4l2_buf_ops = { > + .verify_planes_array = __verify_planes_array_core, > .fill_user_buffer = __fill_v4l2_buffer, > .fill_vb2_buffer = __fill_vb2_buffer, > .set_timestamp = __set_timestamp, > Clean upstream cherry pick, seems to do what it says, so.. Acked-by: Colin Ian King <colin.king@canonical.com>
Though the change does not really make it obvious how this helps. I assume having a verify operation defined will call it at the right stages...
Applied to xenial master-next branch. Cheers, -- Luís
diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c index 502984c724ff..6c441be8f893 100644 --- a/drivers/media/v4l2-core/videobuf2-v4l2.c +++ b/drivers/media/v4l2-core/videobuf2-v4l2.c @@ -67,6 +67,11 @@ static int __verify_planes_array(struct vb2_buffer *vb, const struct v4l2_buffer return 0; } +static int __verify_planes_array_core(struct vb2_buffer *vb, const void *pb) +{ + return __verify_planes_array(vb, pb); +} + /** * __verify_length() - Verify that the bytesused value for each plane fits in * the plane length and that the data offset doesn't exceed the bytesused value. @@ -432,6 +437,7 @@ static int __fill_vb2_buffer(struct vb2_buffer *vb, } static const struct vb2_buf_ops v4l2_buf_ops = { + .verify_planes_array = __verify_planes_array_core, .fill_user_buffer = __fill_v4l2_buffer, .fill_vb2_buffer = __fill_vb2_buffer, .set_timestamp = __set_timestamp,