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.cassandra.auth;
  
  import java.net.InetAddress;
  import java.security.cert.Certificate;
  import java.util.Map;
  import java.util.Set;
  
  import com.google.common.collect.Sets;
  
  import org.apache.cassandra.config.Config;
  import org.apache.cassandra.config.DatabaseDescriptor;
  import org.apache.cassandra.config.EncryptionOptions;
  import org.apache.cassandra.exceptions.ConfigurationException;
  
  /**
   * This authenticator can be used in optional mTLS mode, If the client doesn't make an mTLS connection
   * this fallbacks to password authentication.
   */
  public class MutualTlsWithPasswordFallbackAuthenticator extends PasswordAuthenticator
  {
      private final MutualTlsAuthenticator mutualTlsAuthenticator;
  
      private final Set<AuthenticationMode> AUTHENTICATION_MODES;
  
      public MutualTlsWithPasswordFallbackAuthenticator(Map<String, String> parameters)
      {
          mutualTlsAuthenticator = new MutualTlsAuthenticator(parameters);
          AUTHENTICATION_MODES = Sets.union(super.getSupportedAuthenticationModes(), mutualTlsAuthenticator.getSupportedAuthenticationModes());
      }
  
      @Override
      public void setup()
      {
          super.setup();
          mutualTlsAuthenticator.setup();
      }
  
      @Override
      public boolean supportsEarlyAuthentication()
      {
          return true;
      }
  
      @Override
      public Set<AuthenticationMode> getSupportedAuthenticationModes()
      {
          return AUTHENTICATION_MODES;
      }
  
      @Override
      public SaslNegotiator newSaslNegotiator(InetAddress clientAddress, Certificate[] certificates)
      {
          if (certificates == null || certificates.length == 0)
          {
              // If no certificates present, fallback to PasswordAuthentication
              return newSaslNegotiator(clientAddress);
          }
          // Otherwise attempt to authenticate using the client-provided certificate.
          return mutualTlsAuthenticator.newSaslNegotiator(clientAddress, certificates);
      }
  
      @Override
      public void validateConfiguration() throws ConfigurationException
      {
          Config config = DatabaseDescriptor.getRawConfig();
          if (config.client_encryption_options.getClientAuth() == EncryptionOptions.ClientEncryptionOptions.ClientAuth.NOT_REQUIRED)
          {
              String msg = "MutualTlsWithPasswordFallbackAuthenticator requires client_encryption_options.require_client_auth to be optional/true";
              throw new ConfigurationException(msg);
          }
      }
  }
  