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media: v4l2-ctrls: validate HEVC active reference counts

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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: d395a78db9 ("media: hevc: Add decode params control")
Cc: stable@vger.kernel.org
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
This commit is contained in:
Pengpeng Hou 2026-03-24 11:13:26 +08:00 committed by Hans Verkuil
parent 05ec592de0
commit afbe4bc252
1 changed files with 13 additions and 0 deletions
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13
drivers/media/v4l2-core/v4l2-ctrls-core.c
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@ -971,6 +971,7 @@ static int std_validate_compound(const struct v4l2_ctrl *ctrl, u32 idx,
struct v4l2_ctrl_hevc_ext_sps_st_rps *p_hevc_st_rps;
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;
@ -1260,6 +1261,18 @@ static int std_validate_compound(const struct v4l2_ctrl *ctrl, u32 idx,
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_HEVC_EXT_SPS_ST_RPS: