avcodec/wmalosslessdec: Fix loop in revert_acfilter()

Fixes: out of array read
Fixes: 20059/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMALOSSLESS_fuzzer-5691776237305856

No testcase except the fuzzed one.

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 2020-01-18 19:28:36 +01:00
parent cce37a22bc
commit 5584c0bb94

View File

@ -823,8 +823,11 @@ static void revert_acfilter(WmallDecodeCtx *s, int tile_size)
pred >>= scaling;
s->channel_residues[ich][i] += (unsigned)pred;
}
for (j = 0; j < order; j++)
prevvalues[j] = s->channel_residues[ich][tile_size - j - 1];
for (j = order - 1; j >= 0; j--)
if (tile_size <= j) {
prevvalues[j] = prevvalues[j - tile_size];
}else
prevvalues[j] = s->channel_residues[ich][tile_size - j - 1];
}
}