avcodec/snowdec: Fix integer overflow in header parsing
authorMichael Niedermayer <michael@niedermayer.cc>
Sun, 5 Nov 2017 20:20:05 +0000 (21:20 +0100)
committerMichael Niedermayer <michael@niedermayer.cc>
Wed, 31 Jan 2018 21:56:14 +0000 (22:56 +0100)
Fixes: 3984/clusterfuzz-testcase-minimized-5265759929368576
Fixes: runtime error: signed integer overflow: -1085585801 + -1094995529 cannot be represented in type 'int'

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit c897a9285846b6a072b9650976afd4f091b7a71f)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
libavcodec/snowdec.c

index 8c30a52..88cee3e 100644 (file)
@@ -371,7 +371,7 @@ static int decode_header(SnowContext *s){
         }
     }
 
-    s->spatial_decomposition_type+= get_symbol(&s->c, s->header_state, 1);
+    s->spatial_decomposition_type+= (unsigned)get_symbol(&s->c, s->header_state, 1);
     if(s->spatial_decomposition_type > 1U){
         av_log(s->avctx, AV_LOG_ERROR, "spatial_decomposition_type %d not supported\n", s->spatial_decomposition_type);
         return AVERROR_INVALIDDATA;
@@ -387,10 +387,10 @@ static int decode_header(SnowContext *s){
     }
 
 
-    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);
-    s->block_max_depth+= get_symbol(&s->c, s->header_state, 1);
+    s->qlog           += (unsigned)get_symbol(&s->c, s->header_state, 1);
+    s->mv_scale       += (unsigned)get_symbol(&s->c, s->header_state, 1);
+    s->qbias          += (unsigned)get_symbol(&s->c, s->header_state, 1);
+    s->block_max_depth+= (unsigned)get_symbol(&s->c, s->header_state, 1);
     if(s->block_max_depth > 1 || s->block_max_depth < 0 || s->mv_scale > 256U){
         av_log(s->avctx, AV_LOG_ERROR, "block_max_depth= %d is too large\n", s->block_max_depth);
         s->block_max_depth= 0;