[FFmpeg-cvslog] avformat/matroskadec: Use rounded down duration in get_cue_desc() check

[Michael Niedermayer]

ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Thu Mar 10 23:24:49 2022 +0100| [478796dcf24d7258d459dd45bb041af312807b31] | committer: Michael Niedermayer

avformat/matroskadec: Use rounded down duration in get_cue_desc() check

Floating point is evil, it would be better if duration was not a double

Fixes: Infinite loop
Fixes: 45123/clusterfuzz-testcase-minimized-ffmpeg_dem_WEBM_DASH_MANIFEST_fuzzer-6725052291219456

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 bd3a03db9aef72ee36a7cc964171e9f52967f4bc)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=478796dcf24d7258d459dd45bb041af312807b31
---

 libavformat/matroskadec.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index a262d29cda..3ba8ef9b68 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -3185,7 +3185,9 @@ static CueDesc get_cue_desc(AVFormatContext *s, int64_t ts, int64_t cues_start)
     int i;
     int nb_index_entries = s->streams[0]->nb_index_entries;
     AVIndexEntry *index_entries = s->streams[0]->index_entries;
-    if (ts >= matroska->duration * matroska->time_scale) return (CueDesc) {-1, -1, -1, -1};
+
+    if (ts >= (int64_t)(matroska->duration * matroska->time_scale))
+        return (CueDesc) {-1, -1, -1, -1};
     for (i = 1; i < nb_index_entries; i++) {
         if (index_entries[i - 1].timestamp * matroska->time_scale <= ts &&
             index_entries[i].timestamp * matroska->time_scale > ts) {