rdblue commented on code in PR #3231: URL: https://github.com/apache/iceberg/pull/3231#discussion_r1279975190
########## core/src/main/java/org/apache/iceberg/encryption/AesGcmInputStream.java: ########## @@ -0,0 +1,264 @@ +/* + * 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.iceberg.encryption; + +import java.io.EOFException; +import java.io.IOException; +import java.nio.ByteBuffer; +import java.nio.ByteOrder; +import org.apache.iceberg.io.IOUtil; +import org.apache.iceberg.io.SeekableInputStream; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; + +public class AesGcmInputStream extends SeekableInputStream { + private final SeekableInputStream sourceStream; + private final byte[] fileAADPrefix; + private final Ciphers.AesGcmDecryptor decryptor; + private final byte[] cipherBlockBuffer; + private final long numBlocks; + private final int lastCipherBlockSize; + private final long plainStreamSize; + + private long plainStreamPosition; + private long currentPlainBlockIndex; + private byte[] currentPlainBlock; + private int currentPlainBlockSize; + private byte[] singleByte; + + AesGcmInputStream( + SeekableInputStream sourceStream, long sourceLength, byte[] aesKey, byte[] fileAADPrefix) { + this.sourceStream = sourceStream; + this.fileAADPrefix = fileAADPrefix; + this.decryptor = new Ciphers.AesGcmDecryptor(aesKey); + this.cipherBlockBuffer = new byte[Ciphers.CIPHER_BLOCK_SIZE]; + + this.plainStreamPosition = 0; + this.currentPlainBlockIndex = -1; + this.currentPlainBlock = null; + this.currentPlainBlockSize = 0; + + long streamLength = sourceLength - Ciphers.GCM_STREAM_HEADER_LENGTH; + long numFullBlocks = Math.toIntExact(streamLength / Ciphers.CIPHER_BLOCK_SIZE); + long cipherFullBlockLength = numFullBlocks * Ciphers.CIPHER_BLOCK_SIZE; + int cipherBytesInLastBlock = Math.toIntExact(streamLength - cipherFullBlockLength); + boolean fullBlocksOnly = (0 == cipherBytesInLastBlock); + this.numBlocks = fullBlocksOnly ? numFullBlocks : numFullBlocks + 1; + this.lastCipherBlockSize = + fullBlocksOnly ? Ciphers.CIPHER_BLOCK_SIZE : cipherBytesInLastBlock; // never 0 + + long lastPlainBlockSize = + (long) lastCipherBlockSize - Ciphers.NONCE_LENGTH - Ciphers.GCM_TAG_LENGTH; + this.plainStreamSize = + numFullBlocks * Ciphers.PLAIN_BLOCK_SIZE + (fullBlocksOnly ? 0 : lastPlainBlockSize); + this.singleByte = new byte[1]; + } + + private void validateHeader() throws IOException { + byte[] headerBytes = new byte[Ciphers.GCM_STREAM_HEADER_LENGTH]; + IOUtil.readFully(sourceStream, headerBytes, 0, headerBytes.length); + + Preconditions.checkState( + Ciphers.GCM_STREAM_MAGIC.equals(ByteBuffer.wrap(headerBytes, 0, 4)), + "Invalid GCM stream: magic does not match AGS1"); + + int plainBlockSize = ByteBuffer.wrap(headerBytes, 4, 4).order(ByteOrder.LITTLE_ENDIAN).getInt(); + Preconditions.checkState( + plainBlockSize == Ciphers.PLAIN_BLOCK_SIZE, + "Invalid GCM stream: block size %d != %d", + plainBlockSize, + Ciphers.PLAIN_BLOCK_SIZE); + } + + @Override + public int available() { + long maxAvailable = plainStreamSize - plainStreamPosition; + // See InputStream.available contract + if (maxAvailable >= Integer.MAX_VALUE) { + return Integer.MAX_VALUE; + } else { + return (int) maxAvailable; + } + } + + private int availableInCurrentBlock() { + if (currentPlainBlockIndex < 0) { Review Comment: When I was refactoring, there was a bug that I fixed when the block for `plainStreamPosition` didn't match `currentPlainBlockIndex`. I ended up fixing the problem by setting `currentPlainBlockIndex = -1` in a place that I had missed. Now that I'm thinking about it more, I think the right solution is actually to update the check here instead. That way the bytes available will only be non-zero if the current block matches the position. Here's a diff that does what I'm talking about and still passes tests: ```diff diff --git a/core/src/main/java/org/apache/iceberg/encryption/AesGcmInputStream.java b/core/src/main/java/org/apache/iceberg/encryption/AesGcmInputStream.java index a63134f31d..88e9b36c25 100644 --- a/core/src/main/java/org/apache/iceberg/encryption/AesGcmInputStream.java +++ b/core/src/main/java/org/apache/iceberg/encryption/AesGcmInputStream.java @@ -97,7 +97,7 @@ public class AesGcmInputStream extends SeekableInputStream { } private int availableInCurrentBlock() { - if (currentPlainBlockIndex < 0) { + if (blockIndex(plainStreamPosition) != currentPlainBlockIndex) { return 0; } @@ -130,10 +130,6 @@ public class AesGcmInputStream extends SeekableInputStream { remainingBytesToRead -= bytesToCopy; resultBufferOffset += bytesToCopy; this.plainStreamPosition += bytesToCopy; - if (blockIndex(plainStreamPosition) != currentPlainBlockIndex) { - // invalidate the current block - this.currentPlainBlockIndex = -1; - } } else if (available() > 0) { decryptBlock(blockIndex(plainStreamPosition)); @@ -157,10 +153,6 @@ public class AesGcmInputStream extends SeekableInputStream { } this.plainStreamPosition = newPos; - if (blockIndex(plainStreamPosition) != currentPlainBlockIndex) { - // invalidate the current block - this.currentPlainBlockIndex = -1; - } } @Override @@ -177,10 +169,6 @@ public class AesGcmInputStream extends SeekableInputStream { } this.plainStreamPosition += n; - if (blockIndex(plainStreamPosition) != currentPlainBlockIndex) { - // invalidate the current block - this.currentPlainBlockIndex = -1; - } return n; } ``` -- This is an automated message from the Apache Git Service. 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