rdblue commented on code in PR #3231: URL: https://github.com/apache/iceberg/pull/3231#discussion_r1278604487
########## core/src/main/java/org/apache/iceberg/encryption/AesGcmInputStream.java: ########## @@ -0,0 +1,274 @@ +/* + * 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.io.UncheckedIOException; +import java.nio.ByteBuffer; +import java.nio.ByteOrder; +import java.util.Arrays; +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 Ciphers.AesGcmDecryptor gcmDecryptor; + private final byte[] cipherBlockBuffer; + private final int cipherBlockSize; + private final int plainBlockSize; + private final int numberOfBlocks; + private final int lastCipherBlockSize; + private final long plainStreamSize; + private final byte[] fileAADPrefix; + + private long plainStreamPosition; + private int currentBlockIndex; + private int currentOffsetInPlainBlock; + private byte[] currentDecryptedBlock; + private int currentDecryptedBlockIndex; + + AesGcmInputStream( + SeekableInputStream sourceStream, long sourceLength, byte[] aesKey, byte[] fileAADPrefix) + throws IOException { + long netSourceLength = netSourceFileLength(sourceLength); + boolean emptyCipherStream = (0 == netSourceLength); + this.sourceStream = sourceStream; + byte[] headerBytes = new byte[Ciphers.GCM_STREAM_HEADER_LENGTH]; + IOUtil.readFully(sourceStream, headerBytes, 0, headerBytes.length); + byte[] magic = new byte[Ciphers.GCM_STREAM_MAGIC_ARRAY.length]; + System.arraycopy(headerBytes, 0, magic, 0, Ciphers.GCM_STREAM_MAGIC_ARRAY.length); + Preconditions.checkState( + Arrays.equals(Ciphers.GCM_STREAM_MAGIC_ARRAY, magic), + "Cannot open encrypted file, it does not begin with magic string " + + Ciphers.GCM_STREAM_MAGIC_STRING); + this.currentDecryptedBlockIndex = -1; + + if (!emptyCipherStream) { + this.plainStreamPosition = 0; + this.fileAADPrefix = fileAADPrefix; + gcmDecryptor = new Ciphers.AesGcmDecryptor(aesKey); + plainBlockSize = + ByteBuffer.wrap(headerBytes, Ciphers.GCM_STREAM_MAGIC_ARRAY.length, 4) + .order(ByteOrder.LITTLE_ENDIAN) + .getInt(); + Preconditions.checkState(plainBlockSize > 0, "Wrong plainBlockSize " + plainBlockSize); + + Preconditions.checkState( + plainBlockSize == AesGcmOutputStream.plainBlockSize, + "Wrong plainBlockSize " + + plainBlockSize + + ". Only size of " + + AesGcmOutputStream.plainBlockSize + + " is currently supported"); + + cipherBlockSize = plainBlockSize + Ciphers.NONCE_LENGTH + Ciphers.GCM_TAG_LENGTH; + this.cipherBlockBuffer = new byte[cipherBlockSize]; + this.currentBlockIndex = 0; + this.currentOffsetInPlainBlock = 0; + + int numberOfFullBlocks = Math.toIntExact(netSourceLength / cipherBlockSize); + int cipherBytesInLastBlock = + Math.toIntExact(netSourceLength - numberOfFullBlocks * cipherBlockSize); + boolean fullBlocksOnly = (0 == cipherBytesInLastBlock); + numberOfBlocks = fullBlocksOnly ? numberOfFullBlocks : numberOfFullBlocks + 1; + lastCipherBlockSize = fullBlocksOnly ? cipherBlockSize : cipherBytesInLastBlock; // never 0 + plainStreamSize = calculatePlaintextLength(sourceLength, plainBlockSize); + } else { + plainStreamSize = 0; + + gcmDecryptor = null; + cipherBlockBuffer = null; + cipherBlockSize = -1; + plainBlockSize = -1; + numberOfBlocks = -1; + lastCipherBlockSize = -1; + this.fileAADPrefix = null; + } + } + + @Override + public int available() throws IOException { + long maxAvailable = plainStreamSize - plainStreamPosition; + // See InputStream.available contract + if (maxAvailable >= Integer.MAX_VALUE) { + return Integer.MAX_VALUE; + } else { + return (int) maxAvailable; + } + } + + @Override + public int read(byte[] b, int off, int len) throws IOException { + Preconditions.checkState(len >= 0, "Negative read length " + len); + + if (available() <= 0 && len > 0) { + throw new EOFException(); + } + + if (len == 0) { + return 0; + } + + boolean isLastBlockInStream = (currentBlockIndex + 1 == numberOfBlocks); + int resultBufferOffset = off; + int remainingBytesToRead = len; + + while (remainingBytesToRead > 0) { + byte[] plainBlock = decryptNextBlock(isLastBlockInStream); + + int remainingBytesInBlock = plainBlock.length - currentOffsetInPlainBlock; + boolean finishTheBlock = remainingBytesToRead >= remainingBytesInBlock; + int bytesToCopy = finishTheBlock ? remainingBytesInBlock : remainingBytesToRead; + System.arraycopy(plainBlock, currentOffsetInPlainBlock, b, resultBufferOffset, bytesToCopy); + remainingBytesToRead -= bytesToCopy; + resultBufferOffset += bytesToCopy; + currentOffsetInPlainBlock += bytesToCopy; + + boolean endOfStream = isLastBlockInStream && finishTheBlock; + + if (endOfStream) { + break; + } + + if (finishTheBlock) { + currentBlockIndex++; + currentOffsetInPlainBlock = 0; + isLastBlockInStream = (currentBlockIndex + 1 == numberOfBlocks); + } + } + + plainStreamPosition += len - remainingBytesToRead; + return len - remainingBytesToRead; + } + + @Override + public void seek(long newPos) throws IOException { + if (newPos < 0) { + throw new IOException("Negative new position " + newPos); + } else if (newPos > plainStreamSize) { + throw new EOFException( + "New position " + newPos + " exceeds the max stream size " + plainStreamSize); + } + + currentBlockIndex = Math.toIntExact(newPos / plainBlockSize); + currentOffsetInPlainBlock = Math.toIntExact(newPos % plainBlockSize); + plainStreamPosition = newPos; + } + + @Override + public long skip(long n) { + if (n <= 0) { + return 0; + } + + if (plainStreamPosition == plainStreamSize) { + return 0; + } + + long newPosition = plainStreamPosition + n; + + if (newPosition > plainStreamSize) { + long skipped = plainStreamSize - plainStreamPosition; + try { + seek(plainStreamSize); + } catch (IOException e) { + throw new UncheckedIOException(e); + } + return skipped; + } + + try { + seek(newPosition); + } catch (IOException e) { + throw new UncheckedIOException(e); + } + return n; Review Comment: Style: missing newline after the previous control flow block. -- This is an automated message from the Apache Git Service. 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