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[FFmpeg-devel] avcodec/wmv2dec: Check input bits vs. coded MBs

Message ID 20190430234521.24958-1-michael@niedermayer.cc
State Accepted
Commit e5ce10514918cec2ca25cf48e0dcc80d68e18656
Headers show

Commit Message

Michael Niedermayer April 30, 2019, 11:45 p.m. UTC 
Fixes: Timeout (94sec ->8sec)
Fixes: 14387/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMV2_fuzzer-5723546887651328

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/wmv2dec.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Michael Niedermayer May 12, 2019, 12:55 p.m. UTC | #1 
On Wed, May 01, 2019 at 01:45:21AM +0200, Michael Niedermayer wrote:
> Fixes: Timeout (94sec ->8sec)
> Fixes: 14387/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMV2_fuzzer-5723546887651328
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/wmv2dec.c | 9 +++++++++
>  1 file changed, 9 insertions(+)

will apply


[...]
diff mbox

Patch

diff --git a/libavcodec/wmv2dec.c b/libavcodec/wmv2dec.c
index 124dfdb7e0..afa65478e3 100644
--- a/libavcodec/wmv2dec.c
+++ b/libavcodec/wmv2dec.c
@@ -33,6 +33,7 @@ 
 static int parse_mb_skip(Wmv2Context *w)
 {
     int mb_x, mb_y;
+    int coded_mb_count = 0;
     MpegEncContext *const s = &w->s;
     uint32_t *const mb_type = s->current_picture_ptr->mb_type;
 
@@ -83,6 +84,14 @@  static int parse_mb_skip(Wmv2Context *w)
         }
         break;
     }
+
+    for (mb_y = 0; mb_y < s->mb_height; mb_y++)
+        for (mb_x = 0; mb_x < s->mb_width; mb_x++)
+            coded_mb_count += !IS_SKIP(mb_type[mb_y * s->mb_stride + mb_x]);
+
+    if (coded_mb_count > get_bits_left(&s->gb))
+        return AVERROR_INVALIDDATA;
+
     return 0;
 }