Patch "[media] videobuf2-v4l2: Verify planes array in buffer dequeueing" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

[media] videobuf2-v4l2: Verify planes array in buffer dequeueing

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
videobuf2-v4l2-verify-planes-array-in-buffer-dequeueing.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Sakari Ailus <[email protected]>
Date: Sun, 3 Apr 2016 16:31:03 -0300
Subject: [media] videobuf2-v4l2: Verify planes array in buffer dequeueing

From: Sakari Ailus <[email protected]>

commit 83934b75c368f529d084815c463a7ef781dc9751 upstream.

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!

---
 drivers/media/v4l2-core/videobuf2-v4l2.c |    6 ++++++
 1 file changed, 6 insertions(+)

@@ -67,6 +67,11 @@ static int __verify_planes_array(struct
 	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_
 }
 
 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,

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/vb2-core-skip-planes-array-verification-if-pb-is-null.patch queue-4.4/videobuf2-v4l2-verify-planes-array-in-buffer-dequeueing.patch