[FFmpeg-devel] [PR] avcodec/exif: Check that the values read exist in the input (PR #21714)

[michaelni via ffmpeg-devel <ffmpeg-devel@ffmpeg.org>]

PR #21714 opened by michaelni
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21714
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21714.patch

Fixes: Timeout
Fixes: 471568865/clusterfuzz-testcase-minimized-ffmpeg_dem_AVI_fuzzer-4864048211755008
Fixes: 471951381/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_DEC_fuzzer-5069855998148608

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


>From b314a26e2ef3786550a082ef87c6ab51ea0a1209 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Tue, 10 Feb 2026 13:36:03 +0100
Subject: [PATCH] avcodec/exif: Check that the values read exist in the input

Fixes: Timeout
Fixes: 471568865/clusterfuzz-testcase-minimized-ffmpeg_dem_AVI_fuzzer-4864048211755008
Fixes: 471951381/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_DEC_fuzzer-5069855998148608

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/exif.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/exif.c b/libavcodec/exif.c
index a184733e80..e422b28b8d 100644
--- a/libavcodec/exif.c
+++ b/libavcodec/exif.c
@@ -270,6 +270,9 @@ static inline void tput64(PutByteContext *pb, const int le, const uint64_t value
 
 static int exif_read_values(void *logctx, GetByteContext *gb, int le, AVExifEntry *entry)
 {
+    if (exif_sizes[entry->type] * entry->count > bytestream2_get_bytes_left(gb))
+        return AVERROR_INVALIDDATA;
+
     switch (entry->type) {
         case AV_TIFF_SHORT:
         case AV_TIFF_LONG:
-- 
2.52.0

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