From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from nblzone-211-213.nblnetworks.fi ([83.145.211.213]:57020 "EHLO hillosipuli.retiisi.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754376AbcDFLqX (ORCPT ); Wed, 6 Apr 2016 07:46:23 -0400 From: Sakari Ailus To: linux-media@vger.kernel.org, hverkuil@xs4all.nl Cc: m.chehab@osg.samsung.com Subject: [PATCH 2/2] videobuf2-v4l2: Verify planes array in buffer dequeueing Date: Wed, 6 Apr 2016 14:46:08 +0300 Message-Id: <1459943168-18406-3-git-send-email-sakari.ailus@linux.intel.com> In-Reply-To: <1459943168-18406-1-git-send-email-sakari.ailus@linux.intel.com> References: <1459943168-18406-1-git-send-email-sakari.ailus@linux.intel.com> Sender: linux-media-owner@vger.kernel.org List-ID: 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 --- 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, -- 2.1.4