[FFmpeg-cvslog] avformat/mov: Use av_mul_q() to avoid integer overflows

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Nov 22 19:13:01 2020 +0100| [4f70e1ec0cfa8ae24b224faf522c1d6ca95a42f6] | committer: Michael Niedermayer

avformat/mov: Use av_mul_q() to avoid integer overflows

Fixes: signed integer overflow: 538976288 * 538976288 cannot be represented in type 'int'
Fixes: 27473/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-5758978289827840

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=4f70e1ec0cfa8ae24b224faf522c1d6ca95a42f6
---

 libavformat/mov.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index ad0b9a58d3..8eacf2cc04 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -2354,12 +2354,10 @@ FF_ENABLE_DEPRECATION_WARNINGS
             if (tmcd_ctx->tmcd_flags & 0x0008) {
                 int timescale = AV_RB32(st->codecpar->extradata + 8);
                 int framedur = AV_RB32(st->codecpar->extradata + 12);
-                st->avg_frame_rate.num *= timescale;
-                st->avg_frame_rate.den *= framedur;
+                st->avg_frame_rate = av_mul_q(st->avg_frame_rate, (AVRational){timescale, framedur});
 #if FF_API_LAVF_AVCTX
 FF_DISABLE_DEPRECATION_WARNINGS
-                st->codec->time_base.den *= timescale;
-                st->codec->time_base.num *= framedur;
+                st->codec->time_base = av_mul_q(st->codec->time_base , (AVRational){framedur, timescale});
 FF_ENABLE_DEPRECATION_WARNINGS
 #endif
             }