[FFmpeg-cvslog] h264_sei: Fix infinite loop.

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Thu Jan 26 19:31:01 2012 +0100| [9decfc17bb76da34734296048d390b176abf404c] | committer: Michael Niedermayer

h264_sei: Fix infinite loop.

Fixes not yet fixed parts of CVE-2011-3946.

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=9decfc17bb76da34734296048d390b176abf404c
---

 libavcodec/h264_sei.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/libavcodec/h264_sei.c b/libavcodec/h264_sei.c
index 374e53d..80d70e5 100644
--- a/libavcodec/h264_sei.c
+++ b/libavcodec/h264_sei.c
@@ -169,11 +169,15 @@ int ff_h264_decode_sei(H264Context *h){
 
         type=0;
         do{
+            if (get_bits_left(&s->gb) < 8)
+                return -1;
             type+= show_bits(&s->gb, 8);
         }while(get_bits(&s->gb, 8) == 255);
 
         size=0;
         do{
+            if (get_bits_left(&s->gb) < 8)
+                return -1;
             size+= show_bits(&s->gb, 8);
         }while(get_bits(&s->gb, 8) == 255);