Re: [PATCH v2] videobuf2-core: Verify planes lengths for output buffers

Pawel Osciak
2012-11-09T23:34:08Z

On Tue, Oct 16, 2012 at 8:37 AM, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> For output buffers application provide to the kernel the number of bytes
> they stored in each plane of the buffer. Verify that the value is
> smaller than or equal to the plane length.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---

Acked-by: Pawel Osciak <pawel@osciak.com>

> drivers/media/v4l2-core/videobuf2-core.c | 39 ++++++++++++++++++++++++++++++
> 1 files changed, 39 insertions(+), 0 deletions(-)
>
> Changes compared to v1:
>
> - Sanity check the data_offset value for each plane.
>
> diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
> index 432df11..479337d 100644
> --- a/drivers/media/v4l2-core/videobuf2-core.c
> +++ b/drivers/media/v4l2-core/videobuf2-core.c
> @@ -296,6 +296,41 @@ static int __verify_planes_array(struct vb2_buffer *vb, const struct v4l2_buffer
> }
>
> /**
> + * __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.
> + */
> +static int __verify_length(struct vb2_buffer *vb, const struct v4l2_buffer *b)
> +{
> + unsigned int length;
> + unsigned int plane;
> +
> + if (!V4L2_TYPE_IS_OUTPUT(b->type))
> + return 0;
> +
> + if (V4L2_TYPE_IS_MULTIPLANAR(b->type)) {
> + for (plane = 0; plane < vb->num_planes; ++plane) {
> + length = (b->memory == V4L2_MEMORY_USERPTR)
> + ? b->m.planes[plane].length
> + : vb->v4l2_planes[plane].length;
> +
> + if (b->m.planes[plane].bytesused > length)
> + return -EINVAL;
> + if (b->m.planes[plane].data_offset >=
> + b->m.planes[plane].bytesused)
> + return -EINVAL;
> + }
> + } else {
> + length = (b->memory == V4L2_MEMORY_USERPTR)
> + ? b->length : vb->v4l2_planes[0].length;
> +
> + if (b->bytesused > length)
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +/**
> * __buffer_in_use() - return true if the buffer is in use and
> * the queue cannot be freed (by the means of REQBUFS(0)) call
> */
> @@ -975,6 +1010,10 @@ static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b)
> struct vb2_queue *q = vb->vb2_queue;
> int ret;
>
> + ret = __verify_length(vb, b);
> + if (ret < 0)
> + return ret;
> +
> switch (q->memory) {
> case V4L2_MEMORY_MMAP:
> ret = __qbuf_mmap(vb, b);
> --
> Regards,
>
> Laurent Pinchart
>

--
Best regards,
Pawel Osciak