[FFmpeg-devel] [PATCH 1/2] avformat/matroskadec: Check desc_bytes

[Michael Niedermayer]

Fixes: Division by 0
Fixes: 44035/clusterfuzz-testcase-minimized-ffmpeg_dem_WEBM_DASH_MANIFEST_fuzzer-4826721386364928

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavformat/matroskadec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 5a9acfb247..f433391a16 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -4216,6 +4216,8 @@ static int64_t webm_dash_manifest_compute_bandwidth(AVFormatContext *s, int64_t
             do {
                 int64_t desc_bytes = desc_end.end_offset - desc_beg.start_offset;
                 int64_t desc_ns = desc_end.end_time_ns - desc_beg.start_time_ns;
+                if (desc_bytes <= 0)
+                    return -1;
                 double desc_sec = desc_ns / nano_seconds_per_second;
                 double calc_bits_per_second = (desc_bytes * 8) / desc_sec;
 
-- 
2.17.1