[FFmpeg-cvslog] avcodec/ralf: use multiply instead of shift to avoid undefined behavior in decode_block()
Michael Niedermayer
git at videolan.org
Fri Nov 22 01:04:18 EET 2019
ffmpeg | branch: release/4.0 | Michael Niedermayer <michael at niedermayer.cc> | Sat Nov 2 15:52:52 2019 +0100| [38cfa9d5f974086721e0d501e22b3b2eb1de0712] | committer: Michael Niedermayer
avcodec/ralf: use multiply instead of shift to avoid undefined behavior in decode_block()
Fixes: left shift of negative value -249
Fixes: 18566/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_RALF_fuzzer-5649394561187840
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 1b7d02642b2096622cee6165fea1301bb9ad54ff)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=38cfa9d5f974086721e0d501e22b3b2eb1de0712
---
libavcodec/ralf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libavcodec/ralf.c b/libavcodec/ralf.c
index 1d881cf7ae..ca8817aa21 100644
--- a/libavcodec/ralf.c
+++ b/libavcodec/ralf.c
@@ -408,7 +408,7 @@ static int decode_block(AVCodecContext *avctx, GetBitContext *gb,
case 4:
for (i = 0; i < len; i++) {
t = ch1[i] + ctx->bias[1];
- t2 = ((ch0[i] + ctx->bias[0]) << 1) | (t & 1);
+ t2 = ((ch0[i] + ctx->bias[0]) * 2) | (t & 1);
dst0[i] = (t2 + t) / 2;
dst1[i] = (t2 - t) / 2;
}
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