1. ffmpeg
  2. Commit 38cfa9d5f974086721e0d501e22b3b2eb1de0712
Browse code

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@niedermayer.cc>
(cherry picked from commit 1b7d02642b2096622cee6165fea1301bb9ad54ff)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

Michael Niedermayer authored on 2019/11/02 23:52:52
Showing 1 changed files
libavcodec/ralf.c
History View file @ 38cfa9d
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@@ -408,7 +408,7 @@ static int decode_block(AVCodecContext *avctx, GetBitContext *gb,
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     case 4:
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         for (i = 0; i < len; i++) {
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             t  =   ch1[i] + ctx->bias[1];
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-            t2 = ((ch0[i] + ctx->bias[0]) << 1) | (t & 1);
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+            t2 = ((ch0[i] + ctx->bias[0]) * 2) | (t & 1);
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             dst0[i] = (t2 + t) / 2;
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             dst1[i] = (t2 - t) / 2;
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         }