[FFmpeg-cvslog] avformat/mvi: Check count for overflow

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Mon Oct 19 17:39:30 2020 +0200| [a413ed98632127342ad04b26e0ba0dc26adb70c9] | committer: Michael Niedermayer

avformat/mvi: Check count for overflow

Fixes: left shift of 21378748 by 10 places cannot be represented in type 'int'
Fixes: 26449/clusterfuzz-testcase-minimized-ffmpeg_dem_MVI_fuzzer-5680463374712832

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=a413ed98632127342ad04b26e0ba0dc26adb70c9
---

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

diff --git a/libavformat/mvi.c b/libavformat/mvi.c
index ff5c08bf51..06c9cfe3f0 100644
--- a/libavformat/mvi.c
+++ b/libavformat/mvi.c
@@ -123,6 +123,8 @@ static int read_packet(AVFormatContext *s, AVPacket *pkt)
         count = (mvi->audio_size_counter + mvi->audio_frame_size + 512) >> MVI_FRAC_BITS;
         if (count > mvi->audio_size_left)
             count = mvi->audio_size_left;
+        if ((int64_t)count << MVI_FRAC_BITS > INT_MAX)
+            return AVERROR_INVALIDDATA;
         if ((ret = av_get_packet(pb, pkt, count)) < 0)
             return ret;
         pkt->stream_index = MVI_AUDIO_STREAM_INDEX;