PR #23309 opened by michaelni
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23309
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23309.patch

a valid RLE bitmap can decompress to far more than its input size, an early 
end-of-picture code
leaves the rest of the canvas blank, thus we cannot add a check in bmp decode

Fixes: Timeout
Fixes: 
510821718/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_BMP_DEC_fuzzer-5011979420106752
Found-by: continuous fuzzing process 
https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <[email protected]>

# Summary of changes

Briefly describe what this PR does and why.

<!--
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>From eecd770dc2b74d3704523843dce6fb89f17d6eac Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <[email protected]>
Date: Mon, 1 Jun 2026 00:29:00 +0200
Subject: [PATCH] tools/target_dec_fuzzer: reduce BMP max pixels to avoid RLE
 timeout

a valid RLE bitmap can decompress to far more than its input size, an early 
end-of-picture code
leaves the rest of the canvas blank, thus we cannot add a check in bmp decode

Fixes: Timeout
Fixes: 
510821718/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_BMP_DEC_fuzzer-5011979420106752
Found-by: continuous fuzzing process 
https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <[email protected]>
---
 tools/target_dec_fuzzer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/target_dec_fuzzer.c b/tools/target_dec_fuzzer.c
index dff354545a..723f7996d7 100644
--- a/tools/target_dec_fuzzer.c
+++ b/tools/target_dec_fuzzer.c
@@ -220,6 +220,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t 
size) {
     case AV_CODEC_ID_BETHSOFTVID: maxpixels  /= 8192;  break;
     case AV_CODEC_ID_BFI:         maxpixels  /= 8192;  break;
     case AV_CODEC_ID_BINKVIDEO:   maxpixels  /= 32;    break;
+    case AV_CODEC_ID_BMP:         maxpixels  /= 16;    break;
     case AV_CODEC_ID_BONK:        maxsamples /= 1<<20; break;
     case AV_CODEC_ID_CAVS:        maxpixels  /= 1024;  break;
     case AV_CODEC_ID_CDTOONS:     maxpixels  /= 1024;  break;
-- 
2.52.0

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