[FFmpeg-cvslog] avcodec/mpeg4videodec: Check for multiple VOL headers

[Michael Niedermayer]

ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Sun May 21 16:01:27 2017 +0200| [8bc5e90bb218aab85791b11d38ae65df958b8c2f] | committer: Michael Niedermayer

avcodec/mpeg4videodec: Check for multiple VOL headers

Fixes multiple: runtime error: signed integer overflow: 2147115008 + 413696 cannot be represented in type 'int'
Fixes: 1723/clusterfuzz-testcase-minimized-5309409372667904
Fixes: 1727/clusterfuzz-testcase-minimized-5900685306494976
Fixes: 1737/clusterfuzz-testcase-minimized-5922321338466304

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 efeb47fd5d5cbf980e52a6d5e741c3c74b94b5e2)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=8bc5e90bb218aab85791b11d38ae65df958b8c2f
---

 libavcodec/mpeg4videodec.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index 7cdd6bf759..75f079c78c 100644
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -2548,6 +2548,7 @@ int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
     MpegEncContext *s = &ctx->m;
     unsigned startcode, v;
     int ret;
+    int vol = 0;
 
     /* search next start code */
     align_get_bits(gb);
@@ -2636,6 +2637,11 @@ int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
         }
 
         if (startcode >= 0x120 && startcode <= 0x12F) {
+            if (vol) {
+                av_log(s->avctx, AV_LOG_ERROR, "Multiple VOL headers");
+                return AVERROR_INVALIDDATA;
+            }
+            vol++;
             if ((ret = decode_vol_header(ctx, gb)) < 0)
                 return ret;
         } else if (startcode == USER_DATA_STARTCODE) {