[FFmpeg-cvslog] avcodec/takdec: Fix integer overflow in decode_lpc()

[Michael Niedermayer]

ffmpeg | branch: release/3.0 | Michael Niedermayer <michael at niedermayer.cc> | Fri Sep 22 20:45:27 2017 +0200| [2c84969cb4aef2526e11d070af5c300b5b4e3818] | committer: Michael Niedermayer

avcodec/takdec: Fix integer overflow in decode_lpc()

Fixes: runtime error: signed integer overflow: 16748560 + 2143729712 cannot be represented in type 'int'
Fixes: 3202/clusterfuzz-testcase-minimized-4988291642294272

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 5d31f03a0264cac24434c8108daef4ccba6d28f9)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=2c84969cb4aef2526e11d070af5c300b5b4e3818
---

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

diff --git a/libavcodec/takdec.c b/libavcodec/takdec.c
index e6867eb1b9..b494c5888d 100644
--- a/libavcodec/takdec.c
+++ b/libavcodec/takdec.c
@@ -195,7 +195,7 @@ static void decode_lpc(int32_t *coeffs, int mode, int length)
         int a1 = *coeffs++;
         for (i = 0; i < length - 1 >> 1; i++) {
             *coeffs   += a1;
-            coeffs[1] += *coeffs;
+            coeffs[1] += (unsigned)*coeffs;
             a1         = coeffs[1];
             coeffs    += 2;
         }