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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.cassandra.security;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.ShortBufferException;
import com.google.common.base.Preconditions;
import io.netty.util.concurrent.FastThreadLocal;
import org.apache.cassandra.db.commitlog.EncryptedSegment;
import org.apache.cassandra.io.compress.ICompressor;
import org.apache.cassandra.io.util.ChannelProxy;
import org.apache.cassandra.io.util.FileDataInput;
import org.apache.cassandra.utils.ByteBufferUtil;
/**
* Encryption and decryption functions specific to the commit log.
* See comments in {@link EncryptedSegment} for details on the binary format.
* The normal, and expected, invocation pattern is to compress then encrypt the data on the encryption pass,
* then decrypt and uncompress the data on the decrypt pass.
*/
public class EncryptionUtils
{
public static final int COMPRESSED_BLOCK_HEADER_SIZE = 4;
public static final int ENCRYPTED_BLOCK_HEADER_SIZE = 8;
private static final FastThreadLocal reusableBuffers = new FastThreadLocal()
{
protected ByteBuffer initialValue()
{
return ByteBuffer.allocate(ENCRYPTED_BLOCK_HEADER_SIZE);
}
};
/**
* Compress the raw data, as well as manage sizing of the {@code outputBuffer}; if the buffer is not big enough,
* deallocate current, and allocate a large enough buffer.
* Write the two header lengths (plain text length, compressed length) to the beginning of the buffer as we want those
* values encapsulated in the encrypted block, as well.
*
* @return the byte buffer that was actaully written to; it may be the {@code outputBuffer} if it had enough capacity,
* or it may be a new, larger instance. Callers should capture the return buffer (if calling multiple times).
*/
public static ByteBuffer compress(ByteBuffer inputBuffer, ByteBuffer outputBuffer, boolean allowBufferResize, ICompressor compressor) throws IOException
{
int inputLength = inputBuffer.remaining();
final int compressedLength = compressor.initialCompressedBufferLength(inputLength);
outputBuffer = ByteBufferUtil.ensureCapacity(outputBuffer, compressedLength + COMPRESSED_BLOCK_HEADER_SIZE, allowBufferResize);
outputBuffer.putInt(inputLength);
compressor.compress(inputBuffer, outputBuffer);
outputBuffer.flip();
return outputBuffer;
}
/**
* Encrypt the input data, and writes out to the same input buffer; if the buffer is not big enough,
* deallocate current, and allocate a large enough buffer.
* Writes the cipher text and headers out to the channel, as well.
*
* Note: channel is a parameter as we cannot write header info to the output buffer as we assume the input and output
* buffers can be the same buffer (and writing the headers to a shared buffer will corrupt any input data). Hence,
* we write out the headers directly to the channel, and then the cipher text (once encrypted).
*/
public static ByteBuffer encryptAndWrite(ByteBuffer inputBuffer, WritableByteChannel channel, boolean allowBufferResize, Cipher cipher) throws IOException
{
final int plainTextLength = inputBuffer.remaining();
final int encryptLength = cipher.getOutputSize(plainTextLength);
ByteBuffer outputBuffer = inputBuffer.duplicate();
outputBuffer = ByteBufferUtil.ensureCapacity(outputBuffer, encryptLength, allowBufferResize);
// it's unfortunate that we need to allocate a small buffer here just for the headers, but if we reuse the input buffer
// for the output, then we would overwrite the first n bytes of the real data with the header data.
ByteBuffer intBuf = ByteBuffer.allocate(ENCRYPTED_BLOCK_HEADER_SIZE);
intBuf.putInt(0, encryptLength);
intBuf.putInt(4, plainTextLength);
channel.write(intBuf);
try
{
cipher.doFinal(inputBuffer, outputBuffer);
}
catch (ShortBufferException | IllegalBlockSizeException | BadPaddingException e)
{
throw new IOException("failed to encrypt commit log block", e);
}
outputBuffer.position(0).limit(encryptLength);
channel.write(outputBuffer);
outputBuffer.position(0).limit(encryptLength);
return outputBuffer;
}
@SuppressWarnings("resource")
public static ByteBuffer encrypt(ByteBuffer inputBuffer, ByteBuffer outputBuffer, boolean allowBufferResize, Cipher cipher) throws IOException
{
Preconditions.checkNotNull(outputBuffer, "output buffer may not be null");
return encryptAndWrite(inputBuffer, new ChannelAdapter(outputBuffer), allowBufferResize, cipher);
}
/**
* Decrypt the input data, as well as manage sizing of the {@code outputBuffer}; if the buffer is not big enough,
* deallocate current, and allocate a large enough buffer.
*
* @return the byte buffer that was actaully written to; it may be the {@code outputBuffer} if it had enough capacity,
* or it may be a new, larger instance. Callers should capture the return buffer (if calling multiple times).
*/
public static ByteBuffer decrypt(ReadableByteChannel channel, ByteBuffer outputBuffer, boolean allowBufferResize, Cipher cipher) throws IOException
{
ByteBuffer metadataBuffer = reusableBuffers.get();
if (metadataBuffer.capacity() < ENCRYPTED_BLOCK_HEADER_SIZE)
{
metadataBuffer = ByteBufferUtil.ensureCapacity(metadataBuffer, ENCRYPTED_BLOCK_HEADER_SIZE, true);
reusableBuffers.set(metadataBuffer);
}
metadataBuffer.position(0).limit(ENCRYPTED_BLOCK_HEADER_SIZE);
channel.read(metadataBuffer);
if (metadataBuffer.remaining() < ENCRYPTED_BLOCK_HEADER_SIZE)
throw new IllegalStateException("could not read encrypted blocked metadata header");
int encryptedLength = metadataBuffer.getInt();
// this is the length of the compressed data
int plainTextLength = metadataBuffer.getInt();
outputBuffer = ByteBufferUtil.ensureCapacity(outputBuffer, Math.max(plainTextLength, encryptedLength), allowBufferResize);
outputBuffer.position(0).limit(encryptedLength);
channel.read(outputBuffer);
ByteBuffer dupe = outputBuffer.duplicate();
dupe.clear();
try
{
cipher.doFinal(outputBuffer, dupe);
}
catch (ShortBufferException | IllegalBlockSizeException | BadPaddingException e)
{
throw new IOException("failed to decrypt commit log block", e);
}
dupe.position(0).limit(plainTextLength);
return dupe;
}
// path used when decrypting commit log files
@SuppressWarnings("resource")
public static ByteBuffer decrypt(FileDataInput fileDataInput, ByteBuffer outputBuffer, boolean allowBufferResize, Cipher cipher) throws IOException
{
return decrypt(new DataInputReadChannel(fileDataInput), outputBuffer, allowBufferResize, cipher);
}
/**
* Uncompress the input data, as well as manage sizing of the {@code outputBuffer}; if the buffer is not big enough,
* deallocate current, and allocate a large enough buffer.
*
* @return the byte buffer that was actaully written to; it may be the {@code outputBuffer} if it had enough capacity,
* or it may be a new, larger instance. Callers should capture the return buffer (if calling multiple times).
*/
public static ByteBuffer uncompress(ByteBuffer inputBuffer, ByteBuffer outputBuffer, boolean allowBufferResize, ICompressor compressor) throws IOException
{
int outputLength = inputBuffer.getInt();
outputBuffer = ByteBufferUtil.ensureCapacity(outputBuffer, outputLength, allowBufferResize);
compressor.uncompress(inputBuffer, outputBuffer);
outputBuffer.position(0).limit(outputLength);
return outputBuffer;
}
public static int uncompress(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset, ICompressor compressor) throws IOException
{
int outputLength = readInt(input, inputOffset);
inputOffset += 4;
inputLength -= 4;
if (output.length - outputOffset < outputLength)
{
String msg = String.format("buffer to uncompress into is not large enough; buf size = %d, buf offset = %d, target size = %s",
output.length, outputOffset, outputLength);
throw new IllegalStateException(msg);
}
return compressor.uncompress(input, inputOffset, inputLength, output, outputOffset);
}
private static int readInt(byte[] input, int inputOffset)
{
return (input[inputOffset + 3] & 0xFF)
| ((input[inputOffset + 2] & 0xFF) << 8)
| ((input[inputOffset + 1] & 0xFF) << 16)
| ((input[inputOffset] & 0xFF) << 24);
}
/**
* A simple {@link java.nio.channels.Channel} adapter for ByteBuffers.
*/
private static final class ChannelAdapter implements WritableByteChannel
{
private final ByteBuffer buffer;
private ChannelAdapter(ByteBuffer buffer)
{
this.buffer = buffer;
}
public int write(ByteBuffer src)
{
int count = src.remaining();
buffer.put(src);
return count;
}
public boolean isOpen()
{
return true;
}
public void close()
{
// nop
}
}
private static class DataInputReadChannel implements ReadableByteChannel
{
private final FileDataInput fileDataInput;
private DataInputReadChannel(FileDataInput dataInput)
{
this.fileDataInput = dataInput;
}
public int read(ByteBuffer dst) throws IOException
{
int readLength = dst.remaining();
// we should only be performing encrypt/decrypt operations with on-heap buffers, so calling BB.array() should be legit here
fileDataInput.readFully(dst.array(), dst.position(), readLength);
return readLength;
}
public boolean isOpen()
{
try
{
return fileDataInput.isEOF();
}
catch (IOException e)
{
return true;
}
}
public void close()
{
// nop
}
}
public static class ChannelProxyReadChannel implements ReadableByteChannel
{
private final ChannelProxy channelProxy;
private volatile long currentPosition;
public ChannelProxyReadChannel(ChannelProxy channelProxy, long currentPosition)
{
this.channelProxy = channelProxy;
this.currentPosition = currentPosition;
}
public int read(ByteBuffer dst) throws IOException
{
int bytesRead = channelProxy.read(dst, currentPosition);
dst.flip();
currentPosition += bytesRead;
return bytesRead;
}
public long getCurrentPosition()
{
return currentPosition;
}
public boolean isOpen()
{
return channelProxy.isCleanedUp();
}
public void close()
{
// nop
}
public void setPosition(long sourcePosition)
{
this.currentPosition = sourcePosition;
}
}
}