[FFmpeg-cvslog] avcodec/vp3: Clear context on reinitialization failure

[Michael Niedermayer]

ffmpeg | branch: release/2.8 | Michael Niedermayer <michael at niedermayer.cc> | Sat Nov 28 00:23:54 2015 +0100| [d32c9723a626701a5a508db7ceba9e8b8a774921] | committer: Michael Niedermayer

avcodec/vp3: Clear context on reinitialization failure

Fixes null pointer dereference
Fixes: 1536b9b096a8f95b742bae9d3d761cc6/signal_sigsegv_294aaed_2039_8d1797aeb823ea43858d0fa45c9eb899.ogv

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 6105b7219a90438deae71b0dc5a034c71ee30fc0)

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d32c9723a626701a5a508db7ceba9e8b8a774921
---

 libavcodec/vp3.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c
index 09e6f75..59cd725 100644
--- a/libavcodec/vp3.c
+++ b/libavcodec/vp3.c
@@ -2016,17 +2016,19 @@ static int vp3_decode_frame(AVCodecContext *avctx,
             vp3_decode_end(avctx);
             ret = theora_decode_header(avctx, &gb);
 
+            if (ret >= 0)
+                ret = vp3_decode_init(avctx);
             if (ret < 0) {
                 vp3_decode_end(avctx);
-            } else
-                ret = vp3_decode_init(avctx);
+            }
             return ret;
         } else if (type == 2) {
             ret = theora_decode_tables(avctx, &gb);
+            if (ret >= 0)
+                ret = vp3_decode_init(avctx);
             if (ret < 0) {
                 vp3_decode_end(avctx);
-            } else
-                ret = vp3_decode_init(avctx);
+            }
             return ret;
         }