[FFmpeg-cvslog] avcodec/truemotion2: Fix integer overflow in tm2_null_res_block()

[Michael Niedermayer]

ffmpeg | branch: release/4.1 | Michael Niedermayer <michael at niedermayer.cc> | Sat Mar 16 02:30:57 2019 +0100| [cb4768e7f20b6bc6eef28266ee9a3361967e65df] | committer: Michael Niedermayer

avcodec/truemotion2: Fix integer overflow in tm2_null_res_block()

Fixes: signed integer overflow: 1111638592 - -2122219136 cannot be represented in type 'int'
Fixes: 13441/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TRUEMOTION2_fuzzer-5732769815068672

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 1223696c725a8ea7e80498e6ccfab37eea179b76)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=cb4768e7f20b6bc6eef28266ee9a3361967e65df
---

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

diff --git a/libavcodec/truemotion2.c b/libavcodec/truemotion2.c
index c583ff4032..1aa7a4b870 100644
--- a/libavcodec/truemotion2.c
+++ b/libavcodec/truemotion2.c
@@ -591,7 +591,8 @@ static inline void tm2_null_res_block(TM2Context *ctx, AVFrame *pic, int bx, int
 {
     int i;
     int ct;
-    int left, right, diff;
+    unsigned left, right;
+    int diff;
     int deltas[16];
     TM2_INIT_POINTERS();