flyrain commented on code in PR #3231: URL: https://github.com/apache/iceberg/pull/3231#discussion_r902970238
########## core/src/main/java/org/apache/iceberg/encryption/AesGcmInputStream.java: ########## @@ -0,0 +1,212 @@ +/* + * 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.IOException; +import java.nio.ByteBuffer; +import java.nio.ByteOrder; +import java.security.GeneralSecurityException; +import java.util.Arrays; +import javax.crypto.Cipher; +import javax.crypto.SecretKey; +import javax.crypto.spec.GCMParameterSpec; +import javax.crypto.spec.SecretKeySpec; +import org.apache.iceberg.io.SeekableInputStream; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; + +public class AesGcmInputStream extends SeekableInputStream { + private SeekableInputStream sourceStream; + private long netSourceFileSize; + + private Cipher gcmCipher; + private SecretKey key; + private byte[] nonce; + + private byte[] ciphertextBlockBuffer; + private int cipherBlockSize; + private int plainBlockSize; + private long plainStreamPosition; + private int currentBlockIndex; + private int currentOffsetInPlainBlock; + private int numberOfBlocks; + private int lastBlockSize; + private long plainStreamSize; + private byte[] fileAadPrefix; + + AesGcmInputStream(SeekableInputStream sourceStream, long sourceLength, + byte[] aesKey, byte[] fileAadPrefix) throws IOException { + this.netSourceFileSize = sourceLength - AesGcmOutputStream.PREFIX_LENGTH; + this.sourceStream = sourceStream; + byte[] prefixBytes = new byte[AesGcmOutputStream.PREFIX_LENGTH]; + int fetched = sourceStream.read(prefixBytes); + Preconditions.checkArgument(fetched == AesGcmOutputStream.PREFIX_LENGTH, + "Insufficient read " + fetched); + this.plainStreamPosition = 0; + this.fileAadPrefix = fileAadPrefix; + + byte[] magic = new byte[AesGcmOutputStream.MAGIC_ARRAY.length]; + System.arraycopy(prefixBytes, 0, magic, 0, AesGcmOutputStream.MAGIC_ARRAY.length); + + Preconditions.checkArgument(Arrays.equals(AesGcmOutputStream.MAGIC_ARRAY, magic), + "File with wrong magic string. Should start with " + AesGcmOutputStream.MAGIC_STRING); + + plainBlockSize = ByteBuffer.wrap(prefixBytes, AesGcmOutputStream.MAGIC_ARRAY.length, 4) + .order(ByteOrder.LITTLE_ENDIAN).getInt(); + cipherBlockSize = plainBlockSize + AesGcmOutputStream.GCM_NONCE_LENGTH + AesGcmOutputStream.GCM_TAG_LENGTH; + + try { + gcmCipher = Cipher.getInstance("AES/GCM/NoPadding"); + } catch (GeneralSecurityException e) { + throw new IOException(e); + } + this.nonce = new byte[AesGcmOutputStream.GCM_NONCE_LENGTH]; + this.key = new SecretKeySpec(aesKey, "AES"); + this.ciphertextBlockBuffer = new byte[cipherBlockSize]; + this.currentBlockIndex = 0; + this.currentOffsetInPlainBlock = 0; + + numberOfBlocks = (int) (netSourceFileSize / cipherBlockSize); + lastBlockSize = (int) (netSourceFileSize % cipherBlockSize); + if (lastBlockSize == 0) { + lastBlockSize = cipherBlockSize; + } else { + numberOfBlocks += 1; + } + + plainStreamSize = (numberOfBlocks - 1L) * plainBlockSize + + (lastBlockSize - AesGcmOutputStream.GCM_NONCE_LENGTH - AesGcmOutputStream.GCM_TAG_LENGTH); + } + + public long plaintextStreamSize() { + return plainStreamSize; + } + + @Override + public int available() throws IOException { + return Math.toIntExact(plainStreamSize - plainStreamPosition); + } + + @Override + public int read(byte[] b) throws IOException { + return read(b, 0, b.length); + } + + @Override + public int read(byte[] b, int off, int len) throws IOException { + if (len <= 0) { + throw new IOException("Negative read length " + len); + } + + if (available() <= 0) { + return -1; + } + + boolean lastBlock = currentBlockIndex + 1 == numberOfBlocks; + int resultBufferOffset = off; + int remaining = len; + + sourceStream.seek(AesGcmOutputStream.PREFIX_LENGTH + currentBlockIndex * cipherBlockSize); + + while (remaining > 0) { + int toLoad = lastBlock ? lastBlockSize : cipherBlockSize; + int loaded = sourceStream.read(ciphertextBlockBuffer, 0, toLoad); + if (loaded != toLoad) { + throw new IOException("Read " + loaded + " instead of " + toLoad); + } + + // Copy nonce + System.arraycopy(ciphertextBlockBuffer, 0, nonce, 0, AesGcmOutputStream.GCM_NONCE_LENGTH); + + byte[] aad = AesGcmOutputStream.calculateAAD(fileAadPrefix, currentBlockIndex); + byte[] plaintextBlock; + try { + GCMParameterSpec spec = new GCMParameterSpec(AesGcmOutputStream.GCM_TAG_LENGTH_BITS, nonce); + gcmCipher.init(Cipher.DECRYPT_MODE, key, spec); + gcmCipher.updateAAD(aad); + + plaintextBlock = gcmCipher.doFinal(ciphertextBlockBuffer, AesGcmOutputStream.GCM_NONCE_LENGTH, + toLoad - AesGcmOutputStream.GCM_NONCE_LENGTH); + } catch (GeneralSecurityException e) { + throw new IOException("Failed to decrypt", e); + } + + int remainingInBlock = plaintextBlock.length - currentOffsetInPlainBlock; + boolean finishTheBlock = remaining >= remainingInBlock; + int toCopy = finishTheBlock ? remainingInBlock : remaining; + + System.arraycopy(plaintextBlock, currentOffsetInPlainBlock, b, resultBufferOffset, toCopy); + remaining -= toCopy; + resultBufferOffset += toCopy; + currentOffsetInPlainBlock += toCopy; + boolean endOfStream = lastBlock && finishTheBlock; + if (endOfStream) { + break; + } + if (finishTheBlock) { + currentBlockIndex++; + currentOffsetInPlainBlock = 0; + lastBlock = currentBlockIndex + 1 == numberOfBlocks; + } + } + + plainStreamPosition += len - remaining; + return len - remaining; + } + + @Override + public void seek(long newPos) throws IOException { + if (newPos >= plainStreamSize) { + throw new IOException("At or beyond max stream size " + plainStreamSize + ", " + newPos); + } + currentBlockIndex = Math.toIntExact(newPos / plainBlockSize); + currentOffsetInPlainBlock = Math.toIntExact(newPos % plainBlockSize); + plainStreamPosition = newPos; + } + + @Override + public long getPos() throws IOException { + return plainStreamPosition; + } + + @Override + public int read() throws IOException { + throw new UnsupportedOperationException(); + } + + @Override + public void close() throws IOException { + sourceStream.close(); + } + + @Override + public synchronized void mark(int readlimit) { + throw new UnsupportedOperationException(); + } + + @Override + public synchronized void reset() throws IOException { + throw new UnsupportedOperationException(); Review Comment: Looks like we don't have to implement it, the abstract class `InputStream` has the same logic. -- This is an automated message from the Apache Git Service. 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