[FFmpeg-devel] [PATCH 2/2] avcodec/diracdec: Fix integer overflow in divide3()

Michael Niedermayer michael at niedermayer.cc
Fri Jul 28 00:49:27 EEST 2017


Fixes: runtime error: signed integer overflow: -1073746548 * 21845 cannot be represented in type 'int'
Fixes: 2729/clusterfuzz-testcase-minimized-5902915464069120

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/diracdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/diracdec.c b/libavcodec/diracdec.c
index d2262ebbf5..d2aaeab011 100644
--- a/libavcodec/diracdec.c
+++ b/libavcodec/diracdec.c
@@ -249,7 +249,7 @@ enum dirac_subband {
 /* magic number division by 3 from schroedinger */
 static inline int divide3(int x)
 {
-    return ((x+1)*21845 + 10922) >> 16;
+    return (int)((x+1U)*21845 + 10922) >> 16;
 }
 
 static DiracFrame *remove_frame(DiracFrame *framelist[], int picnum)
-- 
2.13.0



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