[FFmpeg-cvslog] avcodec/snowdec: Check mv_scale
Michael Niedermayer
git at videolan.org
Thu Oct 26 19:39:05 EEST 2017
ffmpeg | branch: release/3.3 | Michael Niedermayer <michael at niedermayer.cc> | Fri Oct 13 03:06:54 2017 +0200| [e8fd32b69ffdf7e3eba7b1223c1f66e69687307f] | committer: Michael Niedermayer
avcodec/snowdec: Check mv_scale
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 at niedermayer.cc>
(cherry picked from commit 393d6fc7395611a38792e3c271b2be42ac45e672)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e8fd32b69ffdf7e3eba7b1223c1f66e69687307f
---
libavcodec/snowdec.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/libavcodec/snowdec.c b/libavcodec/snowdec.c
index 0ac0b55012..6eff729a19 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) {
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