ffmpeg | branch: master | Michael Niedermayer <michael@niedermayer.cc> | Fri Apr 23 19:11:03 2021 +0200| [527821a2dd6f19d9a4d2abe05833346ae86c66c6] | committer: Michael Niedermayer avformat/avidec: fix position overflow in avi_load_index() Fixes: signed integer overflow: 9223372033098784808 + 4294967072 cannot be represented in type 'long' Fixes: 29102/clusterfuzz-testcase-minimized-ffmpeg_dem_AVI_fuzzer-6732488912273408 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=527821a2dd6f19d9a4...

libavformat/avidec.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/libavformat/avidec.c b/libavformat/avidec.c index 2e261c94e6..5d695b9839 100644 --- a/libavformat/avidec.c +++ b/libavformat/avidec.c @@ -1776,7 +1776,10 @@ static int avi_load_index(AVFormatContext *s) size = avio_rl32(pb); if (avio_feof(pb)) break; - next = avio_tell(pb) + size + (size & 1); + next = avio_tell(pb); + if (next < 0 || next > INT64_MAX - size - (size & 1)) + break; + next += size + (size & 1LL); if (tag == MKTAG('i', 'd', 'x', '1') && avi_read_idx1(s, size) >= 0) {