[FFmpeg-cvslog] 4xmdec: fix integer overflow, null ptr dereference

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Tue Nov 20 02:59:55 2012 +0100| [aed128f07d142a7afc51f1f0c572a31b3b9bc2a6] | committer: Michael Niedermayer

4xmdec: fix integer overflow, null ptr dereference

 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=aed128f07d142a7afc51f1f0c572a31b3b9bc2a6
---

 libavcodec/4xm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c
index bd70692..bf0241a 100644
--- a/libavcodec/4xm.c
+++ b/libavcodec/4xm.c
@@ -428,7 +428,7 @@ static int decode_p_frame(FourXContext *f, const uint8_t *buf, int length)
         bytestream_size = FFMAX(length - bitstream_size - wordstream_size, 0);
     }
 
-    if (bitstream_size > length ||
+    if (bitstream_size > length || bitstream_size >= INT_MAX/8 ||
         bytestream_size > length - bitstream_size ||
         wordstream_size > length - bytestream_size - bitstream_size ||
         extra > length - bytestream_size - bitstream_size - wordstream_size) {