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[FFmpeg-devel,2/2] avcodec/snowdec: Check mv_scale

Message ID 20171013010654.16525-2-michael@niedermayer.cc
State Accepted
Commit 393d6fc7395611a38792e3c271b2be42ac45e672
Headers show

Commit Message

Michael Niedermayer Oct. 13, 2017, 1:06 a.m. UTC 
Fixes: runtime error: signed integer overflow: 2 * -1094995530 cannot be represented in type 'int'
Fixes: 3512/clusterfuzz-testcase-minimized-4812747210489856

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/snowdec.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
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Patch

diff --git a/libavcodec/snowdec.c b/libavcodec/snowdec.c
index b74c468ce3..13668c2105 100644
--- a/libavcodec/snowdec.c
+++ b/libavcodec/snowdec.c
@@ -394,9 +394,10 @@  static int decode_header(SnowContext *s){
     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);
-    if(s->block_max_depth > 1 || s->block_max_depth < 0){
+    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;
+        s->mv_scale = 0;
         return AVERROR_INVALIDDATA;
     }
     if (FFABS(s->qbias) > 127) {