[PATCH] media: vcodec: Fix potential array out-of-bounds in vb2ops_venc_queue_setup

[Chen-Yu Tsai]

On Tue, Mar 28, 2023 at 09:26:08AM +0000, Wei Chen wrote:
> variable *nplanes is provided by user via system call argument. The
> possible value of q_data->fmt->num_planes is 1-3, while the value
> of *nplanes can be 1-8. The array access by index i can cause array
> out-of-bounds.
> 
> Fix this bug by checking *nplanes against the array size.

This should have a fixes tag:

Fixes: 4e855a6efa54 ("[media] vcodec: mediatek: Add Mediatek V4L2 Video Encoder Driver")

And also CC the stable list:

Cc: stable at vger.kernel.org

> Signed-off-by: Wei Chen <harperchen1110 at gmail.com>

Reviewed-by: Chen-Yu Tsai <wenst at chromium.org>

> ---
>  drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c
> index d65800a3b89d..1ea02f9136f6 100644
> --- a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c
> +++ b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_enc.c
> @@ -821,6 +821,8 @@ static int vb2ops_venc_queue_setup(struct vb2_queue *vq,
>  		return -EINVAL;
>  
>  	if (*nplanes) {
> +		if (*nplanes != q_data->fmt->num_planes)
> +			return -EINVAL;
>  		for (i = 0; i < *nplanes; i++)
>  			if (sizes[i] < q_data->sizeimage[i])
>  				return -EINVAL;
> -- 
> 2.25.1
>