[FFmpeg-cvslog] snow: reject unsupported chroma shifts.

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sat Mar 10 00:08:32 2012 +0100| [1af9fdc3baa47596757da7c401d58710cef45c75] | committer: Michael Niedermayer

snow: reject unsupported chroma shifts.

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=1af9fdc3baa47596757da7c401d58710cef45c75
---

 libavcodec/snowdec.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/libavcodec/snowdec.c b/libavcodec/snowdec.c
index 265d8e7..537a6c6 100644
--- a/libavcodec/snowdec.c
+++ b/libavcodec/snowdec.c
@@ -336,6 +336,11 @@ static int decode_header(SnowContext *s){
         return -1;
     }
 
+    if (s->chroma_h_shift != 1 || s->chroma_v_shift != 1) {
+        av_log(s->avctx, AV_LOG_ERROR, "Invalid chroma shift\n");
+        return AVERROR_PATCHWELCOME;
+    }
+
     s->qlog           += get_symbol(&s->c, s->header_state, 1);
     s->mv_scale       += get_symbol(&s->c, s->header_state, 1);
     s->qbias          += get_symbol(&s->c, s->header_state, 1);