content: /*
   * 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.spark.network.sasl;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import javax.security.sasl.Sasl;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.Unpooled;
  import io.netty.channel.Channel;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.spark.network.client.RpcResponseCallback;
  import org.apache.spark.network.client.TransportClient;
  import org.apache.spark.network.server.RpcHandler;
  import org.apache.spark.network.server.StreamManager;
  import org.apache.spark.network.util.JavaUtils;
  import org.apache.spark.network.util.TransportConf;
  
  /**
   * RPC Handler which performs SASL authentication before delegating to a child RPC handler.
   * The delegate will only receive messages if the given connection has been successfully
   * authenticated. A connection may be authenticated at most once.
   *
   * Note that the authentication process consists of multiple challenge-response pairs, each of
   * which are individual RPCs.
   */
  class SaslRpcHandler extends RpcHandler {
    private static final Logger logger = LoggerFactory.getLogger(SaslRpcHandler.class);
  
    /** Transport configuration. */
    private final TransportConf conf;
  
    /** The client channel. */
    private final Channel channel;
  
    /** RpcHandler we will delegate to for authenticated connections. */
    private final RpcHandler delegate;
  
    /** Class which provides secret keys which are shared by server and client on a per-app basis. */
    private final SecretKeyHolder secretKeyHolder;
  
    private SparkSaslServer saslServer;
    private boolean isComplete;
  
    SaslRpcHandler(
        TransportConf conf,
        Channel channel,
        RpcHandler delegate,
        SecretKeyHolder secretKeyHolder) {
      this.conf = conf;
      this.channel = channel;
      this.delegate = delegate;
      this.secretKeyHolder = secretKeyHolder;
      this.saslServer = null;
      this.isComplete = false;
    }
  
    @Override
    public void receive(TransportClient client, ByteBuffer message, RpcResponseCallback callback) {
      if (isComplete) {
        // Authentication complete, delegate to base handler.
        delegate.receive(client, message, callback);
        return;
      }
  
      ByteBuf nettyBuf = Unpooled.wrappedBuffer(message);
      SaslMessage saslMessage;
      try {
        saslMessage = SaslMessage.decode(nettyBuf);
      } finally {
        nettyBuf.release();
      }
  
      if (saslServer == null) {
        // First message in the handshake, setup the necessary state.
        client.setClientId(saslMessage.appId);
        saslServer = new SparkSaslServer(saslMessage.appId, secretKeyHolder,
          conf.saslServerAlwaysEncrypt());
      }
  
      byte[] response;
      try {
        response = saslServer.response(JavaUtils.bufferToArray(
          saslMessage.body().nioByteBuffer()));
      } catch (IOException ioe) {
        throw new RuntimeException(ioe);
      }
      callback.onSuccess(ByteBuffer.wrap(response));
  
      // Setup encryption after the SASL response is sent, otherwise the client can't parse the
      // response. It's ok to change the channel pipeline here since we are processing an incoming
      // message, so the pipeline is busy and no new incoming messages will be fed to it before this
      // method returns. This assumes that the code ensures, through other means, that no outbound
      // messages are being written to the channel while negotiation is still going on.
      if (saslServer.isComplete()) {
        logger.debug("SASL authentication successful for channel {}", client);
        isComplete = true;
        if (SparkSaslServer.QOP_AUTH_CONF.equals(saslServer.getNegotiatedProperty(Sasl.QOP))) {
          logger.debug("Enabling encryption for channel {}", client);
          SaslEncryption.addToChannel(channel, saslServer, conf.maxSaslEncryptedBlockSize());
          saslServer = null;
        } else {
          saslServer.dispose();
          saslServer = null;
        }
      }
    }
  
    @Override
    public void receive(TransportClient client, ByteBuffer message) {
      delegate.receive(client, message);
    }
  
    @Override
    public StreamManager getStreamManager() {
      return delegate.getStreamManager();
    }
  
    @Override
    public void channelActive(TransportClient client) {
      delegate.channelActive(client);
    }
  
    @Override
    public void channelInactive(TransportClient client) {
      try {
        delegate.channelInactive(client);
      } finally {
        if (saslServer != null) {
          saslServer.dispose();
        }
      }
    }
  
    @Override
    public void exceptionCaught(Throwable cause, TransportClient client) {
      delegate.exceptionCaught(cause, client);
    }
  
  }
  