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 javax.security.sasl.SaslException;
  
  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.TransportClient;
  import org.apache.spark.network.client.TransportClientBootstrap;
  import org.apache.spark.network.util.JavaUtils;
  import org.apache.spark.network.util.TransportConf;
  
  /**
   * Bootstraps a {@link TransportClient} by performing SASL authentication on the connection. The
   * server should be setup with a {@link SaslRpcHandler} with matching keys for the given appId.
   */
  public class SaslClientBootstrap implements TransportClientBootstrap {
    private static final Logger logger = LoggerFactory.getLogger(SaslClientBootstrap.class);
  
    private final boolean encrypt;
    private final TransportConf conf;
    private final String appId;
    private final SecretKeyHolder secretKeyHolder;
  
    public SaslClientBootstrap(TransportConf conf, String appId, SecretKeyHolder secretKeyHolder) {
      this(conf, appId, secretKeyHolder, false);
    }
  
    public SaslClientBootstrap(
        TransportConf conf,
        String appId,
        SecretKeyHolder secretKeyHolder,
        boolean encrypt) {
      this.conf = conf;
      this.appId = appId;
      this.secretKeyHolder = secretKeyHolder;
      this.encrypt = encrypt;
    }
  
    /**
     * Performs SASL authentication by sending a token, and then proceeding with the SASL
     * challenge-response tokens until we either successfully authenticate or throw an exception
     * due to mismatch.
     */
    @Override
    public void doBootstrap(TransportClient client, Channel channel) {
      SparkSaslClient saslClient = new SparkSaslClient(appId, secretKeyHolder, encrypt);
      try {
        byte[] payload = saslClient.firstToken();
  
        while (!saslClient.isComplete()) {
          SaslMessage msg = new SaslMessage(appId, payload);
          ByteBuf buf = Unpooled.buffer(msg.encodedLength() + (int) msg.body().size());
          msg.encode(buf);
          buf.writeBytes(msg.body().nioByteBuffer());
  
          ByteBuffer response = client.sendRpcSync(buf.nioBuffer(), conf.saslRTTimeoutMs());
          payload = saslClient.response(JavaUtils.bufferToArray(response));
        }
  
        client.setClientId(appId);
  
        if (encrypt) {
          if (!SparkSaslServer.QOP_AUTH_CONF.equals(saslClient.getNegotiatedProperty(Sasl.QOP))) {
            throw new RuntimeException(
              new SaslException("Encryption requests by negotiated non-encrypted connection."));
          }
          SaslEncryption.addToChannel(channel, saslClient, conf.maxSaslEncryptedBlockSize());
          saslClient = null;
          logger.debug("Channel {} configured for SASL encryption.", client);
        }
      } catch (IOException ioe) {
        throw new RuntimeException(ioe);
      } finally {
        if (saslClient != null) {
          try {
            // Once authentication is complete, the server will trust all remaining communication.
            saslClient.dispose();
          } catch (RuntimeException e) {
            logger.error("Error while disposing SASL client", e);
          }
        }
      }
    }
  
  }
  