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.aries.blueprint.authorization.impl;
  
  import java.lang.annotation.Annotation;
  import java.lang.reflect.Method;
  import java.security.AccessControlContext;
  import java.security.AccessControlException;
  import java.security.AccessController;
  import java.security.Principal;
  import java.util.Arrays;
  import java.util.HashSet;
  import java.util.Set;
  import javax.annotation.security.PermitAll;
  import javax.annotation.security.RolesAllowed;
  import javax.security.auth.Subject;
  
  import org.apache.aries.blueprint.Interceptor;
  import org.osgi.service.blueprint.reflect.ComponentMetadata;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class AuthorizationInterceptor implements Interceptor {
      private static final Logger LOGGER = LoggerFactory.getLogger(AuthorizationInterceptor.class);
      private Class<?> beanClass;
  
      public AuthorizationInterceptor(Class<?> beanClass) {
          this.beanClass = beanClass;
      }
  
      public int getRank() {
          return 0;
      }
  
      public void postCallWithException(ComponentMetadata cm, Method m, Throwable ex, Object preCallToken) {
      }
  
      public void postCallWithReturn(ComponentMetadata cm, Method m, Object returnType, Object preCallToken)
          throws Exception {
      }
  
      public Object preCall(ComponentMetadata cm, Method m, Object... parameters) throws Throwable {
          Annotation ann = new SecurityAnotationParser().getEffectiveAnnotation(beanClass, m);
          if (ann instanceof PermitAll) {
              return null;
          }
          String[] rolesAr = new String[] {}; // Also applies for @DenyAll
          if (ann instanceof RolesAllowed) {
              rolesAr = ((RolesAllowed) ann).value();
          } 
          Set<String> roles = new HashSet<String>(Arrays.asList(rolesAr));
          AccessControlContext acc = AccessController.getContext();
          Subject subject = Subject.getSubject(acc);
          if (subject == null) {
              throw new AccessControlException("Method call " + m.getDeclaringClass() + "." + m.getName() + " denied. No JAAS login present");
          }
          Set<Principal> principals = subject.getPrincipals();
  
          for (Principal principal : principals) {
              if (roles.contains(principal.getName())) {
                  LOGGER.debug("Granting access to Method: {} for {}.", m, principal);
                  return null;
              }
          }
          String msg = String.format("Method call %s.%s denied. Roles allowed are %s. Your principals are %s.",
                                     m.getDeclaringClass(), m.getName(), roles, getNames(principals));
          throw new AccessControlException(msg);
      }
  
      private String getNames(Set<Principal> principals) {
          StringBuilder sb = new StringBuilder();
          for (Principal principal : principals) {
              sb.append(principal.getName() + " ");
          }
          return sb.toString();
      }
  
  }
  