[PATCH v2] media: mediatek: vcodec: Fix potential array out-of-bounds in decoder queue_setup

[Wei Chen]

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.

Signed-off-by: Wei Chen <harperchen1110@xxxxxxxxx>
---
Changes in v2:
 - Add explicit braces to avoid ambiguous else

 drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec.c b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec.c
index 641f533c417f..173407664cf4 100644
--- a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec.c
+++ b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dec.c
@@ -753,6 +753,13 @@ int vb2ops_vdec_queue_setup(struct vb2_queue *vq, unsigned int *nbuffers,
 	}
 
 	if (*nplanes) {
+		if (vq->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) {
+			if (*nplanes != q_data->fmt->num_planes)
+				return -EINVAL;
+		} else {
+			if (*nplanes != 1)
+				return -EINVAL;
+		}
 		for (i = 0; i < *nplanes; i++) {
 			if (sizes[i] < q_data->sizeimage[i])
 				return -EINVAL;
-- 
2.25.1