[FFmpeg-cvslog] avcodec/dirac_dwt_template: Fix integer overflow in vertical_compose53iL0()

[Michael Niedermayer]

ffmpeg | branch: release/3.1 | Michael Niedermayer <michael at niedermayer.cc> | Fri Aug 18 16:42:58 2017 +0200| [b2f99c424f154df4f912c8ed24f6f99a211fe9cd] | committer: Michael Niedermayer

avcodec/dirac_dwt_template: Fix integer overflow in vertical_compose53iL0()

Fixes: runtime error: signed integer overflow: 2147483646 + 2 cannot be represented in type 'int'
Fixes: 3013/clusterfuzz-testcase-minimized-4644084197097472

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 a165b53daa8a3a526d2328ca72c4aa9e7f163045)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b2f99c424f154df4f912c8ed24f6f99a211fe9cd
---

 libavcodec/dirac_dwt_template.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/dirac_dwt_template.c b/libavcodec/dirac_dwt_template.c
index 972c711cff..e436c247a1 100644
--- a/libavcodec/dirac_dwt_template.c
+++ b/libavcodec/dirac_dwt_template.c
@@ -49,7 +49,7 @@ static void RENAME(vertical_compose53iL0)(uint8_t *_b0, uint8_t *_b1, uint8_t *_
     TYPE *b1 = (TYPE *)_b1;
     TYPE *b2 = (TYPE *)_b2;
     for (i = 0; i < width; i++)
-        b1[i] -= (b0[i] + b2[i] + 2) >> 2;
+        b1[i] -= (int)(b0[i] + (unsigned)b2[i] + 2) >> 2;
 }
 
 static av_always_inline void RENAME(interleave)(TYPE *dst, TYPE *src0, TYPE *src1, int w2,