From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from lb3-smtp-cloud2.xs4all.net ([194.109.24.29]:38613 "EHLO lb3-smtp-cloud2.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751312AbcDFOoj (ORCPT ); Wed, 6 Apr 2016 10:44:39 -0400 Subject: Re: [PATCH 2/2] videobuf2-v4l2: Verify planes array in buffer dequeueing To: Sakari Ailus , linux-media@vger.kernel.org References: <1459943168-18406-1-git-send-email-sakari.ailus@linux.intel.com> <1459943168-18406-3-git-send-email-sakari.ailus@linux.intel.com> Cc: m.chehab@osg.samsung.com From: Hans Verkuil Message-ID: <570520CD.1020808@xs4all.nl> Date: Wed, 6 Apr 2016 07:44:29 -0700 MIME-Version: 1.0 In-Reply-To: <1459943168-18406-3-git-send-email-sakari.ailus@linux.intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 04/06/2016 04:46 AM, Sakari Ailus wrote: > 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 Acked-by: Hans Verkuil Thanks, Hans > --- > 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 91f5521..8da7470 100644 > --- a/drivers/media/v4l2-core/videobuf2-v4l2.c > +++ b/drivers/media/v4l2-core/videobuf2-v4l2.c > @@ -74,6 +74,11 @@ 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. > @@ -437,6 +442,7 @@ 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, > .copy_timestamp = __copy_timestamp, >