[FFmpeg-cvslog] avcodec/cavsdec: Check sym_factor

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Mon May  8 11:55:27 2017 +0200| [279420b5a63b3f254e4932a4afb91759fb50186a] | committer: Michael Niedermayer

avcodec/cavsdec: Check sym_factor

Fixes: runtime error: signed integer overflow: 25984 * 130560 cannot be represented in type 'int'

Fixes: 1404/clusterfuzz-testcase-minimized-5000441286885376

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=279420b5a63b3f254e4932a4afb91759fb50186a
---

 libavcodec/cavsdec.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavcodec/cavsdec.c b/libavcodec/cavsdec.c
index 4d3d2d7c65..eb2464f36d 100644
--- a/libavcodec/cavsdec.c
+++ b/libavcodec/cavsdec.c
@@ -1031,6 +1031,10 @@ static int decode_pic(AVSContext *h)
     h->scale_den[1] = h->dist[1] ? 512/h->dist[1] : 0;
     if (h->cur.f->pict_type == AV_PICTURE_TYPE_B) {
         h->sym_factor = h->dist[0] * h->scale_den[1];
+        if (FFABS(h->sym_factor) > 32768) {
+            av_log(h->avctx, AV_LOG_ERROR, "sym_factor %d too large\n", h->sym_factor);
+            return AVERROR_INVALIDDATA;
+        }
     } else {
         h->direct_den[0] = h->dist[0] ? 16384 / h->dist[0] : 0;
         h->direct_den[1] = h->dist[1] ? 16384 / h->dist[1] : 0;