[FFmpeg-devel] [PATCH 2/6] avformat/vividas: Fixes overflow in shift in recover_key()

Michael Niedermayer michael at niedermayer.cc
Sat Jul 13 23:25:02 EEST 2019


Fixes: left shift of 133 by 24 places cannot be represented in type 'int'
Fixes: 15365/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5716153105645568

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Suggested-by: Reimar Döffinger <Reimar.Doeffinger at gmx.de>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavformat/vividas.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/libavformat/vividas.c b/libavformat/vividas.c
index 350c7aa70a..830e318645 100644
--- a/libavformat/vividas.c
+++ b/libavformat/vividas.c
@@ -115,10 +115,7 @@ static unsigned recover_key(unsigned char sample[4], unsigned expected_size)
 
     put_v(plaintext+2, expected_size);
 
-    return (sample[0]^plaintext[0])|
-        ((sample[1]^plaintext[1])<<8)|
-        ((sample[2]^plaintext[2])<<16)|
-        ((sample[3]^plaintext[3])<<24);
+    return AV_RL32(sample) ^ AV_RL32(plaintext);
 }
 
 static void xor_block(void *p1, void *p2, unsigned size, int key, unsigned *key_ptr)
-- 
2.22.0



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