[FFmpeg-devel] [PATCH 3/4] avcodec/dirac_dwt_template: Fix undefined behavior in interleave()

Michael Niedermayer michael at niedermayer.cc
Thu Jun 14 18:15:17 EEST 2018


Fixes: signed integer overflow: 2147483647 + 1 cannot be represented in type 'int'
Fixes: 8697/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DIRAC_fuzzer-5197148130902016

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

diff --git a/libavcodec/dirac_dwt_template.c b/libavcodec/dirac_dwt_template.c
index 8c25c1f822..528fc7e9e7 100644
--- a/libavcodec/dirac_dwt_template.c
+++ b/libavcodec/dirac_dwt_template.c
@@ -57,8 +57,8 @@ static av_always_inline void RENAME(interleave)(TYPE *dst, TYPE *src0, TYPE *src
 {
     int i;
     for (i = 0; i < w2; i++) {
-        dst[2*i  ] = (src0[i] + add) >> shift;
-        dst[2*i+1] = (src1[i] + add) >> shift;
+        dst[2*i  ] = (src0[i] + (unsigned)add) >> shift;
+        dst[2*i+1] = (src1[i] + (unsigned)add) >> shift;
     }
 }
 
-- 
2.17.1



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