[FFmpeg-cvslog] avcodec/mpeg4videodec: Clear partitioned frame in decode_studio_vop_header()

[Michael Niedermayer]

ffmpeg | branch: release/4.1 | Michael Niedermayer <michael at niedermayer.cc> | Sun Nov  4 19:02:55 2018 +0100| [bc5777bdab7d5515088713f73507d3a49df7695d] | committer: Michael Niedermayer

avcodec/mpeg4videodec: Clear partitioned frame in decode_studio_vop_header()

partitioned_frame is also set/cleared in decode_vop_header()

Fixes: out of array read
Fixes: 9789/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG4_fuzzer-5638681627983872

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 074187d599a2ece2bdf77bd08b4b797c5800eda6)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=bc5777bdab7d5515088713f73507d3a49df7695d
---

 libavcodec/mpeg4videodec.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index 233b8525ce..f44ee76bd4 100644
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -3056,6 +3056,7 @@ static int decode_studio_vop_header(Mpeg4DecContext *ctx, GetBitContext *gb)
     if (get_bits_left(gb) <= 32)
         return 0;
 
+    s->partitioned_frame = 0;
     s->decode_mb = mpeg4_decode_studio_mb;
 
     decode_smpte_tc(ctx, gb);