On 05/12/2016 02:14 PM, Sakari Ailus wrote:
> An earlier patch fixing an input validation issue introduced another
> issue: vb2_core_dqbuf() is called with pb argument value NULL in some
> cases, causing a NULL pointer dereference. Fix this by skipping the
> verification as there's nothing to verify.
>
> Signed-off-by: David R <david@xxxxxxxxxxxxxxx>
>
> Use if () instead of ? :; it's nicer that way. Improve the comment in the
> code as well.
This comment doesn't seem applicable to this patch.
Reviewed-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Hans
>
> Fixes: e7e0c3e26587 ("[media] videobuf2-core: Check user space planes array in dqbuf")
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # for v4.4 and later
> ---
> drivers/media/v4l2-core/videobuf2-core.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
> index 9fbcb67..633fc1a 100644
> --- a/drivers/media/v4l2-core/videobuf2-core.c
> +++ b/drivers/media/v4l2-core/videobuf2-core.c
> @@ -1648,7 +1648,7 @@ static int __vb2_get_done_vb(struct vb2_queue *q, struct vb2_buffer **vb,
> void *pb, int nonblocking)
> {
> unsigned long flags;
> - int ret;
> + int ret = 0;
>
> /*
> * Wait for at least one buffer to become available on the done_list.
> @@ -1664,10 +1664,12 @@ static int __vb2_get_done_vb(struct vb2_queue *q, struct vb2_buffer **vb,
> spin_lock_irqsave(&q->done_lock, flags);
> *vb = list_first_entry(&q->done_list, struct vb2_buffer, done_entry);
> /*
> - * Only remove the buffer from done_list if v4l2_buffer can handle all
> - * the planes.
> + * Only remove the buffer from done_list if all planes can be
> + * handled. Some cases such as V4L2 file I/O and DVB have pb
> + * == NULL; skip the check then as there's nothing to verify.
> */
> - ret = call_bufop(q, verify_planes_array, *vb, pb);
> + if (pb)
> + ret = call_bufop(q, verify_planes_array, *vb, pb);
> if (!ret)
> list_del(&(*vb)->done_entry);
> spin_unlock_irqrestore(&q->done_lock, flags);
>
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