[FFmpeg-devel] [PR] avcodec/hevc/ps: Check bit_depth_cm in/out relation (PR #21783)

[FFmpeg-devel] [PR] avcodec/hevc/ps: Check bit_depth_cm in/out relation (PR #21783)

[michaelni via ffmpeg-devel]

PR #21783 opened by michaelni
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21783
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21783.patch

Fixes: Assertion n>0 && n<=25 failed at ./libavcodec/get_bits.h:3
Fixes: 472463689/clusterfuzz-testcase-minimized-ffmpeg_dem_HXVS_fuzzer-6012944883449856

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>


>From 380104efd0590f7447958d9d4038c7a47efeea6f Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Mon, 16 Feb 2026 01:38:53 +0100
Subject: [PATCH] avcodec/hevc/ps: Check bit_depth_cm in/out relation

Fixes: Assertion n>0 && n<=25 failed at ./libavcodec/get_bits.h:3
Fixes: 472463689/clusterfuzz-testcase-minimized-ffmpeg_dem_HXVS_fuzzer-6012944883449856

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/hevc/ps.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavcodec/hevc/ps.c b/libavcodec/hevc/ps.c
index 9f7a61e794..46b38564d5 100644
--- a/libavcodec/hevc/ps.c
+++ b/libavcodec/hevc/ps.c
@@ -1826,6 +1826,10 @@ static int colour_mapping_table(GetBitContext *gb, AVCodecContext *avctx, HEVCPP
     pps->luma_bit_depth_cm_output   = get_ue_golomb(gb) + 8;
     pps->chroma_bit_depth_cm_output = get_ue_golomb(gb) + 8;
 
+    if (   pps->  luma_bit_depth_cm_output < pps->  luma_bit_depth_cm_input
+        || pps->chroma_bit_depth_cm_output < pps->chroma_bit_depth_cm_input)
+            return AVERROR_INVALIDDATA;
+
     pps->cm_res_quant_bits = get_bits(gb, 2);
     pps->cm_delta_flc_bits = get_bits(gb, 2) + 1;
 
-- 
2.52.0

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