bruno-roustant commented on a change in pull request #1608: URL: https://github.com/apache/lucene-solr/pull/1608#discussion_r448470152
########## File path: lucene/core/src/java/org/apache/lucene/store/EncryptingIndexInput.java ########## @@ -0,0 +1,299 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF 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.apache.lucene.store; + +import javax.crypto.Cipher; +import javax.crypto.ShortBufferException; +import javax.crypto.spec.IvParameterSpec; +import java.io.EOFException; +import java.io.IOException; +import java.io.UncheckedIOException; +import java.nio.ByteBuffer; +import java.security.InvalidAlgorithmParameterException; +import java.security.InvalidKeyException; +import java.security.Key; + +import org.apache.lucene.codecs.CodecUtil; + +import static org.apache.lucene.store.EncryptingIndexOutput.HEADER_LENGTH; +import static org.apache.lucene.store.EncryptingUtil.*; + +public class EncryptingIndexInput extends IndexInput { + + /** + * Must be a multiple of {@link EncryptingUtil#AES_BLOCK_SIZE}. + */ + private static final int BUFFER_SIZE = 64 * AES_BLOCK_SIZE; // 1024 B + + private static final long AES_BLOCK_SIZE_MOD_MASK = AES_BLOCK_SIZE - 1; + static final int HEADER_IV_LENGTH = HEADER_LENGTH + IV_LENGTH; + + private static final byte[] EMPTY_BYTES = new byte[0]; + + // Some fields are not final for the clone() method. + private boolean isClone; + private final long sliceOffset; + private final long sliceEnd; + private IndexInput indexInput; + private final Key key; + private Cipher cipher; + private final byte[] initialIv; + private byte[] iv; + private ReusableIvParameterSpec ivParameterSpec; + private ByteBuffer inBuffer; + private ByteBuffer outBuffer; + private byte[] inArray; + private byte[] oneByteBuf; + private int padding; + private boolean closed; + + public EncryptingIndexInput(IndexInput indexInput, byte[] key) throws IOException { + this("Decrypting " + indexInput.toString(), + HEADER_IV_LENGTH, indexInput.length() - HEADER_IV_LENGTH - CodecUtil.footerLength(), false, + indexInput, createAesKey(key), readInitialIv(indexInput)); + } + + private EncryptingIndexInput(String resourceDescription, long sliceOffset, long sliceLength, boolean isClone, + IndexInput indexInput, Key key, byte[] initialIv) throws IOException { + super(resourceDescription); + assert sliceOffset >= 0 && sliceLength >= 0; + this.sliceOffset = sliceOffset; + this.sliceEnd = sliceOffset + sliceLength; + this.isClone = isClone; + this.indexInput = indexInput; + this.key = key; + this.initialIv = initialIv; + + cipher = createAesCtrCipher(); + assert cipher.getBlockSize() == AES_BLOCK_SIZE : "Invalid AES block size: " + cipher.getBlockSize(); + iv = initialIv.clone(); + ivParameterSpec = new ReusableIvParameterSpec(iv); + try { + cipher.init(Cipher.DECRYPT_MODE, this.key, ivParameterSpec); + } catch (InvalidKeyException | InvalidAlgorithmParameterException e) { + throw new IOException(e); + } + + inBuffer = ByteBuffer.allocate(getBufferSize()); + outBuffer = ByteBuffer.allocate(getBufferSize() + AES_BLOCK_SIZE); + outBuffer.limit(0); + assert inBuffer.hasArray() && outBuffer.hasArray(); + assert inBuffer.arrayOffset() == 0; + inArray = inBuffer.array(); + oneByteBuf = new byte[1]; + } + + /** + * Reads the initial IV at the beginning of the index input. + */ + private static byte[] readInitialIv(IndexInput indexInput) throws IOException { + indexInput.seek(HEADER_LENGTH); + byte[] initialIv = new byte[IV_LENGTH]; + indexInput.readBytes(initialIv, 0, initialIv.length, false); + return initialIv; + } + + /** + * Gets the buffer size. It must be a multiple of {@link EncryptingUtil#AES_BLOCK_SIZE}. + */ + protected int getBufferSize() { + return BUFFER_SIZE; + } + + @Override + public void close() throws IOException { + if (!closed) { + closed = true; + if (!isClone) { + indexInput.close(); + } + } + } + + @Override + public long getFilePointer() { + return getPosition() - sliceOffset; + } + + /** + * Gets the current internal position in the delegate {@link IndexInput}. It includes the initial IV length. + */ + private long getPosition() { + return indexInput.getFilePointer() - outBuffer.remaining(); + } + + @Override + public void seek(long position) throws IOException { + if (position < 0) { + throw new IllegalArgumentException("Invalid position=" + position); + } + if (position > length()) { + throw new EOFException("Seek beyond EOF (position=" + position + ", length=" + length() + ") in " + this); + } + long targetPosition = position + sliceOffset; + long delegatePosition = indexInput.getFilePointer(); + long currentPosition = delegatePosition - outBuffer.remaining(); + if (targetPosition >= currentPosition && targetPosition <= delegatePosition) { + outBuffer.position(outBuffer.position() + (int) (targetPosition - currentPosition)); Review comment: The target position is within the buffered output, which has a small integer size. 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