[FFmpeg-devel] [PATCH] avcodec/utvideodec: Set B for the width= 1 case in restore_median_planar_il() (PR #20872)

[FFmpeg-devel] [PATCH] avcodec/utvideodec: Set B for the width= 1 case in restore_median_planar_il() (PR #20872)

[michaelni via ffmpeg-devel]

PR #20872 opened by michaelni
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20872
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20872.patch

Fixes: use of uninitialized memory
Fixes: 439878388/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_UTVIDEO_DEC_fuzzer-5635866203848704

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


>From 2a1a04c4b0cbe64a534d05ea1a321e6175f5bb2c Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Sat, 8 Nov 2025 23:22:56 +0100
Subject: [PATCH] avcodec/utvideodec: Set B for the width= 1 case in
 restore_median_planar_il()

Fixes: use of uninitialized memory
Fixes: 439878388/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_UTVIDEO_DEC_fuzzer-5635866203848704

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/utvideodec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/utvideodec.c b/libavcodec/utvideodec.c
index bc02ac44d5..098706b705 100644
--- a/libavcodec/utvideodec.c
+++ b/libavcodec/utvideodec.c
@@ -457,7 +457,7 @@ static void restore_median_planar_il(UtvideoContext *c, uint8_t *src, ptrdiff_t
         // second line - first element has top prediction, the rest uses median
         C        = bsrc[-stride2];
         bsrc[0] += C;
-        A        = bsrc[0];
+        A = B    = bsrc[0];
         for (i = 1; i < FFMIN(width, 16); i++) { /* scalar loop (DSP need align 16) */
             B        = bsrc[i - stride2];
             bsrc[i] += mid_pred(A, B, (uint8_t)(A + B - C));
-- 
2.49.1

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