[FFmpeg-cvslog] avcodec/truemotion2: Fix passing null pointer to memset()

[Michael Niedermayer]

ffmpeg | branch: release/3.1 | Michael Niedermayer <michael at niedermayer.cc> | Sun May 28 21:54:02 2017 +0200| [79f75b123b3416a824ae36c2c8a898a4dd1ee820] | committer: Michael Niedermayer

avcodec/truemotion2: Fix passing null pointer to memset()

Fixes part of: 1888/clusterfuzz-testcase-minimized-5237704826552320

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 c901627918ff7480c1bb6f9cae507ee2c7c933d8)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=79f75b123b3416a824ae36c2c8a898a4dd1ee820
---

 libavcodec/truemotion2.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavcodec/truemotion2.c b/libavcodec/truemotion2.c
index 4f0e52dbf7..e6ae05f1d5 100644
--- a/libavcodec/truemotion2.c
+++ b/libavcodec/truemotion2.c
@@ -915,7 +915,8 @@ static int decode_frame(AVCodecContext *avctx,
                             buf_size - offset);
         if (t < 0) {
             int j = tm2_stream_order[i];
-            memset(l->tokens[j], 0, sizeof(**l->tokens) * l->tok_lens[j]);
+            if (l->tok_lens[j])
+                memset(l->tokens[j], 0, sizeof(**l->tokens) * l->tok_lens[j]);
             return t;
         }
         offset += t;