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>
This commit is contained in:
Michael Niedermayer 2019-11-02 15:52:52 +01:00
parent c54b9fc42f
commit 1b7d02642b

View File

@ -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;
}