[FFmpeg-cvslog] avformat/utils: reorder duration computation to avoid overflow

[Michael Niedermayer]

ffmpeg | branch: release/4.3 | Michael Niedermayer <michael at niedermayer.cc> | Sun Jun 21 12:24:04 2020 +0200| [3571d9d654f78c3c16ec17c8260d28f211e9571b] | committer: Michael Niedermayer

avformat/utils: reorder duration computation to avoid overflow

Fixes: signed integer overflow: 8 * 9223372036854774783 cannot be represented in type 'long'
Fixes: 23381/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-4818340509122560

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 10cc82c35baabbb07ffec3faccb04d8928c39e4c)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3571d9d654f78c3c16ec17c8260d28f211e9571b
---

 libavformat/utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/utils.c b/libavformat/utils.c
index 667249362c..ba8aaebfb7 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2782,7 +2782,7 @@ static void estimate_timings_from_bit_rate(AVFormatContext *ic)
                 st      = ic->streams[i];
                 if (   st->time_base.num <= INT64_MAX / ic->bit_rate
                     && st->duration == AV_NOPTS_VALUE) {
-                    duration = av_rescale(8 * filesize, st->time_base.den,
+                    duration = av_rescale(filesize, 8LL * st->time_base.den,
                                           ic->bit_rate *
                                           (int64_t) st->time_base.num);
                     st->duration = duration;