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.ambari.server.security;
  
  import java.io.IOException;
  
  import jakarta.servlet.ServletException;
  import jakarta.servlet.http.HttpServletRequest;
  import jakarta.servlet.http.HttpServletResponse;
  
  import org.apache.ambari.server.configuration.Configuration;
  import org.apache.ambari.server.security.authentication.kerberos.AmbariKerberosAuthenticationProperties;
  import org.springframework.security.core.AuthenticationException;
  import org.springframework.security.web.AuthenticationEntryPoint;
  import org.springframework.stereotype.Component;
  
  @Component
  public class AmbariEntryPoint implements AuthenticationEntryPoint {
  
    /**
     * A Boolean value declaring whether Kerberos authentication has been enabled (<code>true</code>)
     * or not (<code>false</code>).
     * <p>
     * This value determines the behavior this entry point when authentication fails.
     */
    private final boolean kerberosAuthenticationEnabled;
  
    public AmbariEntryPoint(Configuration configuration) {
      AmbariKerberosAuthenticationProperties kerberosAuthenticationProperties = (configuration == null)
          ? null
          : configuration.getKerberosAuthenticationProperties();
  
      kerberosAuthenticationEnabled = (kerberosAuthenticationProperties != null) && kerberosAuthenticationProperties.isKerberosAuthenticationEnabled();
    }
  
    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException authException) throws IOException, ServletException {
      /* *****************************************************************************************
       * If Kerberos authentication is enabled (authentication.kerberos.enabled = true), respond such
       * that the client is challenged to Negotiate and reissue the request with a Kerberos token.
       * This response is an HTTP 401 status with the "WWW-Authenticate: Negotiate" header.
       *
       * If Kerberos authentication is not enabled, return an HTTP 403 status.
       * ****************************************************************************************** */
      if (kerberosAuthenticationEnabled) {
        response.setHeader("WWW-Authenticate", "Negotiate");
        response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Authentication requested");
      } else {
        response.sendError(HttpServletResponse.SC_FORBIDDEN, authException.getMessage());
      }
    }
  }
  