[FFmpeg-cvslog] avcodec/cbs_vp9: Check data_size

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu Dec 26 00:57:07 2019 +0100| [4fa2d5a692f40c398a299acf2c6a20f5b98a3708] | committer: Michael Niedermayer

avcodec/cbs_vp9: Check data_size

Fixes: out of array access
Fixes: 19542/clusterfuzz-testcase-minimized-ffmpeg_BSF_TRACE_HEADERS_fuzzer-5659498341728256

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: James Almer <jamrial at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4fa2d5a692f40c398a299acf2c6a20f5b98a3708
---

 libavcodec/cbs_vp9.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/cbs_vp9.c b/libavcodec/cbs_vp9.c
index 98730e03e3..ec82f11c76 100644
--- a/libavcodec/cbs_vp9.c
+++ b/libavcodec/cbs_vp9.c
@@ -416,6 +416,9 @@ static int cbs_vp9_split_fragment(CodedBitstreamContext *ctx,
     uint8_t superframe_header;
     int err;
 
+    if (frag->data_size == 0)
+        return AVERROR_INVALIDDATA;
+
     // Last byte in the packet.
     superframe_header = frag->data[frag->data_size - 1];