[FFmpeg-cvslog] avformat/mov: do not set sign bit for chunk_offsets
Michael Niedermayer
git at videolan.org
Fri Dec 29 03:11:09 EET 2023
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Fri Dec 15 22:37:49 2023 +0100| [cfc0a68d4d3192779e356a852e71b8218e7a00ab] | committer: Michael Niedermayer
avformat/mov: do not set sign bit for chunk_offsets
Fixes: signed integer overflow: 2314885530818453536 - -7412889664301817824 cannot be represented in type 'long'
Fixes: 64296/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-6304027146846208
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=cfc0a68d4d3192779e356a852e71b8218e7a00ab
---
libavformat/mov.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 4f413bfbd5..88c36f6af3 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -2242,8 +2242,13 @@ static int mov_read_stco(MOVContext *c, AVIOContext *pb, MOVAtom atom)
for (i = 0; i < entries && !pb->eof_reached; i++)
sc->chunk_offsets[i] = avio_rb32(pb);
else if (atom.type == MKTAG('c','o','6','4'))
- for (i = 0; i < entries && !pb->eof_reached; i++)
+ for (i = 0; i < entries && !pb->eof_reached; i++) {
sc->chunk_offsets[i] = avio_rb64(pb);
+ if (sc->chunk_offsets[i] < 0) {
+ av_log(c->fc, AV_LOG_WARNING, "Impossible chunk_offset\n");
+ sc->chunk_offsets[i] = 0;
+ }
+ }
else
return AVERROR_INVALIDDATA;
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