avcodec/snowdec: Fix ref value check
authorMichael Niedermayer <michaelni@gmx.at>
Tue, 24 Feb 2015 02:12:22 +0000 (03:12 +0100)
committerMichael Niedermayer <michaelni@gmx.at>
Wed, 25 Feb 2015 02:37:42 +0000 (03:37 +0100)
Fixes integer overflow and out of array read.
Fixes: signal_sigsegv_24169e6_3445_cov_3778346427_snow_chroma_bug.avi

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 8f4cbf940212079a34753c7f4d6c6b5a43586d30)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
libavcodec/snowdec.c

index c9d40b8..5aae25a 100644 (file)
@@ -153,7 +153,7 @@ static int decode_q_branch(SnowContext *s, int level, int x, int y){
         int l = left->color[0];
         int cb= left->color[1];
         int cr= left->color[2];
-        int ref = 0;
+        unsigned ref = 0;
         int ref_context= av_log2(2*left->ref) + av_log2(2*top->ref);
         int mx_context= av_log2(2*FFABS(left->mx - top->mx)) + 0*av_log2(2*FFABS(tr->mx - top->mx));
         int my_context= av_log2(2*FFABS(left->my - top->my)) + 0*av_log2(2*FFABS(tr->my - top->my));