[FFmpeg-cvslog] avcodec/vp56: Check avctx->error_concealment before enabling EC

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu Mar 16 11:20:46 2017 +0100| [98da63b3f5f5a277c5c3a16860db9a9f6741e54c] | committer: Michael Niedermayer

avcodec/vp56: Check avctx->error_concealment before enabling EC

Fixes timeout with 847/clusterfuzz-testcase-5291877358108672
Fixes timeout with 850/clusterfuzz-testcase-5721296509861888

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=98da63b3f5f5a277c5c3a16860db9a9f6741e54c
---

 libavcodec/vp56.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/vp56.c b/libavcodec/vp56.c
index 4751840..b69fe6c 100644
--- a/libavcodec/vp56.c
+++ b/libavcodec/vp56.c
@@ -712,7 +712,7 @@ static int ff_vp56_decode_mbs(AVCodecContext *avctx, void *data,
                 int ret = vp56_decode_mb(s, mb_row, mb_col, is_alpha);
                 if (ret < 0) {
                     damaged = 1;
-                    if (!s->have_undamaged_frame) {
+                    if (!s->have_undamaged_frame || !avctx->error_concealment) {
                         s->discard_frame = 1;
                         return AVERROR_INVALIDDATA;
                     }