/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.common.compress.lzf;
import com.ning.compress.lzf.ChunkDecoder;
import com.ning.compress.lzf.ChunkEncoder;
import com.ning.compress.lzf.LZFChunk;
import com.ning.compress.lzf.util.ChunkDecoderFactory;
import com.ning.compress.lzf.util.ChunkEncoderFactory;
import org.elasticsearch.test.ElasticsearchTestCase;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
/**
* Test an extremely rare corruption produced by the pure java impl of ChunkEncoder.
*/
public class CorruptedCompressorTests extends ElasticsearchTestCase {
public void testCorruption() throws IOException {
// this test generates a hash collision: [0,1,153,64] hashes the same as [1,153,64,64]
// and then leverages the bug s/inPos/0/ to corrupt the array
// the first array is used to insert a reference from this hash to offset 6
// and then the hash table is reused and still thinks that there is such a hash at position 6
// and at position 7, it finds a sequence with the same hash
// so it inserts a buggy reference
byte[] b1 = new byte[] {0,1,2,3,4,(byte)153,64,64,64,9,9,9,9,9,9,9,9,9,9};
byte[] b2 = new byte[] {1,(byte)153,0,0,0,0,(byte)153,64,64,64,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
ChunkEncoder encoder = ChunkEncoderFactory.safeInstance();
ChunkDecoder decoder = ChunkDecoderFactory.safeInstance();
check(encoder, decoder, b1, 0, b1.length);
final int off = 6;
check(encoder, decoder, b2, off, b2.length - off);
}
private void check(ChunkEncoder encoder, ChunkDecoder decoder, byte[] bytes, int offset, int length) throws IOException {
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
byte[] expected = new byte[length];
byte[] buffer = new byte[LZFChunk.MAX_CHUNK_LEN];
byte[] output = new byte[length];
System.arraycopy(bytes, offset, expected, 0, length);
encoder.encodeAndWriteChunk(bytes, offset, length, outputStream);
System.out.println(Arrays.toString(Arrays.copyOf(outputStream.toByteArray(), 20)));
InputStream inputStream = new ByteArrayInputStream(outputStream.toByteArray());
assertEquals(decoder.decodeChunk(inputStream, buffer, output), length);
System.out.println(Arrays.toString(Arrays.copyOf(output, 20)));
assertArrayEquals(expected, output);
}
}