[FFmpeg-cvslog] avformat/matroskadec: Sanity check codec_id/track type

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Mon Dec  7 00:37:25 2020 +0100| [7b88dd8f0cb48b46f3178d274a9117a3d2307f4e] | committer: Michael Niedermayer

avformat/matroskadec: Sanity check codec_id/track type

Fixes: memleak
Fixes: 27766/clusterfuzz-testcase-minimized-ffmpeg_dem_MATROSKA_fuzzer-5198300814508032

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=7b88dd8f0cb48b46f3178d274a9117a3d2307f4e
---

 libavformat/matroskadec.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 44db2c8358..374831baa3 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -2318,6 +2318,15 @@ static int matroska_parse_tracks(AVFormatContext *s)
         if (!track->codec_id)
             continue;
 
+        if (   track->type == MATROSKA_TRACK_TYPE_AUDIO && track->codec_id[0] != 'A'
+            || track->type == MATROSKA_TRACK_TYPE_VIDEO && track->codec_id[0] != 'V'
+            || track->type == MATROSKA_TRACK_TYPE_SUBTITLE && track->codec_id[0] != 'D' && track->codec_id[0] != 'S'
+            || track->type == MATROSKA_TRACK_TYPE_METADATA && track->codec_id[0] != 'D' && track->codec_id[0] != 'S'
+        ) {
+            av_log(matroska->ctx, AV_LOG_INFO, "Inconsistent track type\n");
+            continue;
+        }
+
         if (track->audio.samplerate < 0 || track->audio.samplerate > INT_MAX ||
             isnan(track->audio.samplerate)) {
             av_log(matroska->ctx, AV_LOG_WARNING,