[FFmpeg-cvslog] avformat/aqtitledec: Skip unrepresentable durations

[Michael Niedermayer]

ffmpeg | branch: release/4.3 | Michael Niedermayer <michael at niedermayer.cc> | Sun Mar 20 00:07:50 2022 +0100| [e1a5738b73b7136fcc118c4528409d34c54e7e4f] | committer: Michael Niedermayer

avformat/aqtitledec: Skip unrepresentable durations

Fixes: signed integer overflow: -5 - 9223372036854775807 cannot be represented in type 'long'
Fixes: 45665/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-475618463934054

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 c2d1597a8a6470045a8da241d4f65c81f26c3107)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e1a5738b73b7136fcc118c4528409d34c54e7e4f
---

 libavformat/aqtitledec.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/aqtitledec.c b/libavformat/aqtitledec.c
index 81630d73b0..960a5d8ef5 100644
--- a/libavformat/aqtitledec.c
+++ b/libavformat/aqtitledec.c
@@ -74,7 +74,8 @@ static int aqt_read_header(AVFormatContext *s)
             new_event = 1;
             pos = avio_tell(s->pb);
             if (sub) {
-                sub->duration = frame - sub->pts;
+                if (frame >= sub->pts && (uint64_t)frame - sub->pts < INT64_MAX)
+                    sub->duration = frame - sub->pts;
                 sub = NULL;
             }
         } else if (*line) {