[GitHub] drill pull request #773: DRILL-4335: Apache Drill should support network enc...

[sohami <gi...@git.apache.org>]

Github user sohami commented on a diff in the pull request:

    https://github.com/apache/drill/pull/773#discussion_r113808458
  
    --- Diff: exec/rpc/src/main/java/org/apache/drill/exec/rpc/SaslDecryptionHandler.java ---
    @@ -0,0 +1,162 @@
    +/*
    + * 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.drill.exec.rpc;
    +
    +import io.netty.buffer.ByteBuf;
    +import io.netty.channel.ChannelHandlerContext;
    +import io.netty.handler.codec.MessageToMessageDecoder;
    +
    +import org.apache.drill.exec.exception.OutOfMemoryException;
    +
    +import java.io.IOException;
    +import java.nio.ByteBuffer;
    +import java.nio.ByteOrder;
    +import java.util.List;
    +
    +import static com.google.common.base.Preconditions.checkArgument;
    +
    +/**
    + * Handler to Decrypt the input ByteBuf. It expects input to be in format where it has length of the bytes to
    + * decode in network order and actual encrypted bytes. The handler reads the length and then reads the
    + * required bytes to pass it to unwrap function for decryption. The decrypted buffer is copied to a new
    + * ByteBuf and added to out list.
    + * <p>
    + * Example:
    + * <li>Input - [EBLN1, EB1, EBLN2, EB2] --> ByteBuf with repeated combination of encrypted byte length
    + *             in network order (EBLNx) and encrypted bytes (EB)
    + * <li>Output - [DB1] --> Decrypted ByteBuf of first chunk.(EB1)
    + * </p>
    + */
    +class SaslDecryptionHandler extends MessageToMessageDecoder<ByteBuf> {
    +
    +  private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(
    +      SaslDecryptionHandler.class.getCanonicalName());
    +
    +  private final SaslCodec saslCodec;
    +
    +  private final int maxEncodedSize;
    +
    +  private final OutOfMemoryHandler outOfMemoryHandler;
    +
    +  private final byte[] encodedMsg;
    +
    +  private final ByteBuffer lengthOctets;
    +
    +  SaslDecryptionHandler(SaslCodec saslCodec, int maxEncodedSize, OutOfMemoryHandler oomHandler) {
    +    this.saslCodec = saslCodec;
    +    this.outOfMemoryHandler = oomHandler;
    +    this.maxEncodedSize = maxEncodedSize;
    +
    +    // Allocate the byte array of maxEncodedSize to reuse for each encoded packet received on this connection
    +    // Maximum value of maxEncodedSize can be 16MB (i.e. OXFFFFFF)
    +    encodedMsg = new byte[maxEncodedSize];
    +    lengthOctets = ByteBuffer.allocate(RpcConstants.LENGTH_FIELD_LENGTH);
    +    lengthOctets.order(ByteOrder.BIG_ENDIAN);
    +  }
    +
    +  @Override
    +  public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
    +    super.handlerAdded(ctx);
    +    logger.trace("Added " + RpcConstants.SASL_DECRYPTION_HANDLER + " handler");
    +  }
    +
    +  @Override
    +  public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
    +    super.handlerRemoved(ctx);
    +    logger.trace("Removed " + RpcConstants.SASL_DECRYPTION_HANDLER + " handler");
    +  }
    +
    +  public void decode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out) throws IOException {
    +
    +    if (!ctx.channel().isOpen()) {
    +      logger.trace("Channel closed before decoding the message of {} bytes", msg.readableBytes());
    +      msg.skipBytes(msg.readableBytes());
    +      return;
    +    }
    +
    +    try {
    +      if(logger.isTraceEnabled()) {
    +        logger.trace("Trying to decrypt the encrypted message of size: {} with maxEncodedSize", msg.readableBytes());
    +      }
    +
    +      final byte[] wrappedMsg;
    +
    +      // All the encrypted blocks are prefixed with it's length in network byte order (or BigEndian format). Netty's
    +      // default Byte order of ByteBuf is Little Endian, so we cannot just do msg.getInt() as that will read the 4
    +      // octets in little endian format.
    +      //
    +      // We will read the length of one complete encrypted chunk and decode that.
    +      msg.getBytes(msg.readerIndex(), lengthOctets.array(), 0, RpcConstants.LENGTH_FIELD_LENGTH);
    +      int wrappedMsgLength = lengthOctets.getInt(0);
    +      msg.skipBytes(RpcConstants.LENGTH_FIELD_LENGTH);
    +
    +      // Since lengthBasedFrameDecoder will ensure we have enough bytes it's good to have this check here.
    +      checkArgument(msg.readableBytes() >= wrappedMsgLength);
    +
    +      // Checks if the original byte buffer is backed by array or not
    +      if (msg.hasArray()) {
    +        wrappedMsg = msg.array();
    +      } else {
    +        if (RpcConstants.EXTRA_DEBUGGING) {
    +          logger.debug("The input bytebuf is not backed by a byte array so allocating a new one");
    +        }
    +
    +        // Check if the wrappedMsgLength doesn't exceed agreed upon maxEncodedSize. As per SASL RFC 2222/4422 we
    +        // should close the connection since it represents a security attack.
    +        if (wrappedMsgLength > maxEncodedSize) {
    +          throw new RpcException(String.format("Received encoded buffer size: %d is larger than negotiated " +
    +              "maxEncodedSize: %d. Closing the connection as this is unexpected.", wrappedMsgLength, maxEncodedSize));
    +        }
    +
    +        wrappedMsg = encodedMsg;
    +        // Copy the wrappedMsgLength of bytes into the byte array
    +        msg.getBytes(msg.readerIndex(), wrappedMsg, 0, wrappedMsgLength);
    +      }
    +
    +      // SASL library always copies the origMsg internally to a new byte array
    --- End diff --
    
    I saw atleast both for GSSAPI/Digest. Looks like this is the general way how usually wrap functions are implemented.


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