[FFmpeg-cvslog] avcodec/mdec: Fix signed integer overflow: 28835400 * 83 cannot be represented in type 'int'

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Fri May  5 22:17:59 2017 +0200| [a234b5ade3ca6cde805b92b8b6ecacf693460a8c] | committer: Michael Niedermayer

avcodec/mdec: Fix signed integer overflow: 28835400 * 83 cannot be represented in type 'int'

Fixes: 1346/clusterfuzz-testcase-minimized-5776732600664064

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=a234b5ade3ca6cde805b92b8b6ecacf693460a8c
---

 libavcodec/mdec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/mdec.c b/libavcodec/mdec.c
index 42bd561cd7..8e28aa04f0 100644
--- a/libavcodec/mdec.c
+++ b/libavcodec/mdec.c
@@ -111,11 +111,11 @@ static inline int mdec_decode_block_intra(MDECContext *a, int16_t *block, int n)
                 j = scantable[i];
                 if (level < 0) {
                     level = -level;
-                    level = (level * qscale * quant_matrix[j]) >> 3;
+                    level = (level * (unsigned)qscale * quant_matrix[j]) >> 3;
                     level = (level - 1) | 1;
                     level = -level;
                 } else {
-                    level = (level * qscale * quant_matrix[j]) >> 3;
+                    level = (level * (unsigned)qscale * quant_matrix[j]) >> 3;
                     level = (level - 1) | 1;
                 }
             }