[FFmpeg-cvslog] avformat/genh: Check block_align

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Mon Oct 19 17:05:01 2020 +0200| [37396e9ba85d8969a3b5e3314ab99ff604845628] | committer: Michael Niedermayer

avformat/genh: Check block_align

Fixes: infinite loop
Fixes: 26440/clusterfuzz-testcase-minimized-ffmpeg_dem_GENH_fuzzer-5632134020333568

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=37396e9ba85d8969a3b5e3314ab99ff604845628
---

 libavformat/genh.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavformat/genh.c b/libavformat/genh.c
index ed9910503d..698104a9d6 100644
--- a/libavformat/genh.c
+++ b/libavformat/genh.c
@@ -146,6 +146,9 @@ static int genh_read_header(AVFormatContext *s)
         }
     }
 
+    if (st->codecpar->block_align <= 0)
+        return AVERROR_INVALIDDATA;
+
     avio_skip(s->pb, start_offset - avio_tell(s->pb));
 
     avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);