[FFmpeg-cvslog] wmadec: Verify bitstream size makes sense before calling init_get_bits.

[Alex Converse]

ffmpeg | branch: release/0.8 | Alex Converse <alex.converse at gmail.com> | Fri Jan 27 14:24:07 2012 -0800| [88b47010c4e2ed0d756f30c54b0d88153c33aec5] | committer: Reinhard Tartler

wmadec: Verify bitstream size makes sense before calling init_get_bits.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
(cherry picked from commit 48f1e5212c90b511c90fa0449655abb06a9edda2)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=88b47010c4e2ed0d756f30c54b0d88153c33aec5
---

 libavcodec/wmadec.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/libavcodec/wmadec.c b/libavcodec/wmadec.c
index 479b34c..c8e1de2 100644
--- a/libavcodec/wmadec.c
+++ b/libavcodec/wmadec.c
@@ -864,6 +864,8 @@ static int wma_decode_superframe(AVCodecContext *avctx,
 
         /* read each frame starting from bit_offset */
         pos = bit_offset + 4 + 4 + s->byte_offset_bits + 3;
+        if (pos >= MAX_CODED_SUPERFRAME_SIZE * 8)
+            return AVERROR_INVALIDDATA;
         init_get_bits(&s->gb, buf + (pos >> 3), (MAX_CODED_SUPERFRAME_SIZE - (pos >> 3))*8);
         len = pos & 7;
         if (len > 0)