[PATCH 6.1 211/609] media: v4l2-ctrls: validate HEVC active reference counts

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Pengpeng Hou <[email protected]>

commit afbe4bc252d90a6f8fad869b06d5430f615f22f9 upstream.

HEVC slice parameters are shared stateless V4L2 controls, but the common
validation path does not verify the active L0/L1 reference counts before
driver-specific code consumes them.

The original report came from Cedrus, but the active count bounds are
not Cedrus-specific. Validate them in the common HEVC slice control path
so stateless HEVC drivers get the same basic guarantees as soon as the
control is queued.

Do not reject ref_idx_l0/ref_idx_l1 entries here. Existing userspace may
use out-of-range sentinel values such as 0xff for missing references, and
some hardware can use that information for concealment. Keep this common
check limited to the active reference counts.

Fixes: d395a78db9eab ("media: hevc: Add decode params control")
Cc: [email protected]
Signed-off-by: Pengpeng Hou <[email protected]>
Reviewed-by: Nicolas Dufresne <[email protected]>
Signed-off-by: Nicolas Dufresne <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/media/v4l2-core/v4l2-ctrls-core.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

--- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
@@ -566,6 +566,7 @@ static int std_validate_compound(const s
 	struct v4l2_ctrl_h264_decode_params *p_h264_dec_params;
 	struct v4l2_ctrl_hevc_sps *p_hevc_sps;
 	struct v4l2_ctrl_hevc_pps *p_hevc_pps;
+	struct v4l2_ctrl_hevc_slice_params *p_hevc_slice_params;
 	struct v4l2_ctrl_hdr10_mastering_display *p_hdr10_mastering;
 	struct v4l2_ctrl_hevc_decode_params *p_hevc_decode_params;
 	struct v4l2_area *area;
@@ -854,6 +855,18 @@ static int std_validate_compound(const s
 		break;
 
 	case V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS:
+		p_hevc_slice_params = p;
+
+		if (p_hevc_slice_params->num_ref_idx_l0_active_minus1 >=
+		    V4L2_HEVC_DPB_ENTRIES_NUM_MAX)
+			return -EINVAL;
+
+		if (p_hevc_slice_params->slice_type != V4L2_HEVC_SLICE_TYPE_B)
+			break;
+
+		if (p_hevc_slice_params->num_ref_idx_l1_active_minus1 >=
+		    V4L2_HEVC_DPB_ENTRIES_NUM_MAX)
+			return -EINVAL;
 		break;
 
 	case V4L2_CTRL_TYPE_HDR10_CLL_INFO: