[FFmpeg-cvslog] avformat/mov: Check element count in mov_metadata_hmmt()

[Michael Niedermayer]

ffmpeg | branch: release/4.3 | Michael Niedermayer <michael at niedermayer.cc> | Mon Feb 15 20:41:31 2021 +0100| [959d2eb7c225e027cdabf27eb3afa7a6172acac0] | committer: Michael Niedermayer

avformat/mov: Check element count in mov_metadata_hmmt()

Fixes: Timeout
Fixes: 30325/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-6048395703746560

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 1d277b92fa4c149d589e6828d4e18ad578406f1f)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=959d2eb7c225e027cdabf27eb3afa7a6172acac0
---

 libavformat/mov.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 697b6908d1..702fc7fac5 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -290,6 +290,8 @@ static int mov_metadata_hmmt(MOVContext *c, AVIOContext *pb, unsigned len)
         return 0;
 
     n_hmmt = avio_rb32(pb);
+    if (n_hmmt > len / 4)
+        return AVERROR_INVALIDDATA;
     for (i = 0; i < n_hmmt && !pb->eof_reached; i++) {
         int moment_time = avio_rb32(pb);
         avpriv_new_chapter(c->fc, i, av_make_q(1, 1000), moment_time, AV_NOPTS_VALUE, NULL);