[FFmpeg-cvslog] mpeg12dec: reset data size after parsing extradata.

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sun Apr 22 20:03:53 2012 +0200| [951cbea56fdc03ef96d07fbd7e5bed755d42ac8a] | committer: Michael Niedermayer

mpeg12dec: reset data size after parsing extradata.

This ended up corrupting data structures and may possibly
lead to a double free.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=951cbea56fdc03ef96d07fbd7e5bed755d42ac8a
---

 libavcodec/mpeg12.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/libavcodec/mpeg12.c b/libavcodec/mpeg12.c
index ea19b81..b66d535 100644
--- a/libavcodec/mpeg12.c
+++ b/libavcodec/mpeg12.c
@@ -2289,6 +2289,7 @@ static int mpeg_decode_frame(AVCodecContext *avctx,
 
     if (avctx->extradata && !avctx->frame_number) {
         int ret = decode_chunks(avctx, picture, data_size, avctx->extradata, avctx->extradata_size);
+        *data_size = 0;
         if (ret < 0 && (avctx->err_recognition & AV_EF_EXPLODE))
             return ret;
     }