[FFmpeg-cvslog] avcodec/vp8: Fix null pointer dereference in ff_vp8_decode_free()

[Michael Niedermayer]

ffmpeg | branch: release/2.6 | Michael Niedermayer <michael at niedermayer.cc> | Sat Jul 18 19:02:26 2015 +0200| [e3a521d817cb7d36acc6e1e7cda8d6a70e967be6] | committer: Michael Niedermayer

avcodec/vp8: Fix null pointer dereference in ff_vp8_decode_free()

Fixes: signal_sigsegv_d5de23_967_vp80_00_comprehensive_010.ivf with memlimit 524288

Found-by: Samuel Groß, Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit a84f0e8d8f293df3c535f9b893730a835bed6520)

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e3a521d817cb7d36acc6e1e7cda8d6a70e967be6
---

 libavcodec/vp8.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/vp8.c b/libavcodec/vp8.c
index 5a458e8..73e9d18 100644
--- a/libavcodec/vp8.c
+++ b/libavcodec/vp8.c
@@ -2689,6 +2689,9 @@ av_cold int ff_vp8_decode_free(AVCodecContext *avctx)
     VP8Context *s = avctx->priv_data;
     int i;
 
+    if (!s)
+        return 0;
+
     vp8_decode_flush_impl(avctx, 1);
     for (i = 0; i < FF_ARRAY_ELEMS(s->frames); i++)
         av_frame_free(&s->frames[i].tf.f);