[FFmpeg-cvslog] avformat/bfi: Check offsets better
Michael Niedermayer
git at videolan.org
Wed Oct 12 15:45:39 EEST 2022
ffmpeg | branch: release/3.4 | Michael Niedermayer <michael at niedermayer.cc> | Sun Mar 20 23:24:40 2022 +0100| [c7e436a0b3031198c1d533fe2543a313a5a33463] | committer: Michael Niedermayer
avformat/bfi: Check offsets better
Fixes: signed integer overflow: -2145378272 - 538976288 cannot be represented in type 'int'
Fixes: 45690/clusterfuzz-testcase-minimized-ffmpeg_IO_DEMUXER_fuzzer-5015496544616448
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 35dc93ab44a57d78956414624c4e011414220e98)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=c7e436a0b3031198c1d533fe2543a313a5a33463
---
libavformat/bfi.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/libavformat/bfi.c b/libavformat/bfi.c
index f32a2cf8ce..a226101f76 100644
--- a/libavformat/bfi.c
+++ b/libavformat/bfi.c
@@ -143,12 +143,12 @@ static int bfi_read_packet(AVFormatContext * s, AVPacket * pkt)
audio_offset = avio_rl32(pb);
avio_rl32(pb);
video_offset = avio_rl32(pb);
- audio_size = video_offset - audio_offset;
- bfi->video_size = chunk_size - video_offset;
- if (audio_size < 0 || bfi->video_size < 0) {
+ if (audio_offset < 0 || video_offset < audio_offset || chunk_size < video_offset) {
av_log(s, AV_LOG_ERROR, "Invalid audio/video offsets or chunk size\n");
return AVERROR_INVALIDDATA;
}
+ audio_size = video_offset - audio_offset;
+ bfi->video_size = chunk_size - video_offset;
//Tossing an audio packet at the audio decoder.
ret = av_get_packet(pb, pkt, audio_size);
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