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[FFmpeg-devel,1/4] avcodec/snowdec: Fix integer overflow in header parsing

Message ID 20171105202008.29966-1-michael@niedermayer.cc
State Accepted
Commit c897a9285846b6a072b9650976afd4f091b7a71f
Headers show

Commit Message

Michael Niedermayer Nov. 5, 2017, 8:20 p.m. UTC 
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>
---
 libavcodec/snowdec.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Comments

Michael Niedermayer Nov. 13, 2017, 6:57 p.m. UTC | #1 
On Sun, Nov 05, 2017 at 09:20:05PM +0100, Michael Niedermayer wrote:
> 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>
> ---
>  libavcodec/snowdec.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)

patchset applied

[...]
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Patch

diff --git a/libavcodec/snowdec.c b/libavcodec/snowdec.c
index 13668c2105..727e908fb5 100644
--- a/libavcodec/snowdec.c
+++ b/libavcodec/snowdec.c
@@ -374,7 +374,7 @@  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;
@@ -390,10 +390,10 @@  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;