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 backtype.storm.security.auth.digest;
  
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.Map;
  
  import backtype.storm.security.auth.ReqContext;
  import backtype.storm.security.auth.SaslTransportPlugin;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import javax.security.auth.Subject;
  import javax.security.auth.callback.Callback;
  import javax.security.auth.callback.CallbackHandler;
  import javax.security.auth.callback.NameCallback;
  import javax.security.auth.callback.PasswordCallback;
  import javax.security.auth.callback.UnsupportedCallbackException;
  import javax.security.auth.login.AppConfigurationEntry;
  import javax.security.auth.login.Configuration;
  import javax.security.sasl.AuthorizeCallback;
  import javax.security.sasl.RealmCallback;
  
  import backtype.storm.security.auth.AuthUtils;
  
  /**
   * SASL server side collback handler
   */
  public class ServerCallbackHandler implements CallbackHandler {
      private static final String USER_PREFIX = "user_";
      private static final Logger LOG = LoggerFactory.getLogger(ServerCallbackHandler.class);
      private static final String SYSPROP_SUPER_PASSWORD = "storm.SASLAuthenticationProvider.superPassword";
  
      private String userName;
      private final Map<String, String> credentials = new HashMap<String, String>();
  
      public ServerCallbackHandler(Configuration configuration) throws IOException {
          if (configuration == null)
              return;
  
          AppConfigurationEntry configurationEntries[] = configuration.getAppConfigurationEntry(AuthUtils.LOGIN_CONTEXT_SERVER);
          if (configurationEntries == null) {
              String errorMessage = "Could not find a '" + AuthUtils.LOGIN_CONTEXT_SERVER + "' entry in this configuration: Server cannot start.";
              throw new IOException(errorMessage);
          }
          credentials.clear();
          for (AppConfigurationEntry entry : configurationEntries) {
              Map<String, ?> options = entry.getOptions();
              // Populate DIGEST-MD5 user -> password map with JAAS configuration entries from the "Server" section.
              // Usernames are distinguished from other options by prefixing the username with a "user_" prefix.
              for (Map.Entry<String, ?> pair : options.entrySet()) {
                  String key = pair.getKey();
                  if (key.startsWith(USER_PREFIX)) {
                      String userName = key.substring(USER_PREFIX.length());
                      credentials.put(userName, (String) pair.getValue());
                  }
              }
          }
      }
  
      public void handle(Callback[] callbacks) throws UnsupportedCallbackException {
          for (Callback callback : callbacks) {
              if (callback instanceof NameCallback) {
                  handleNameCallback((NameCallback) callback);
              } else if (callback instanceof PasswordCallback) {
                  handlePasswordCallback((PasswordCallback) callback);
              } else if (callback instanceof RealmCallback) {
                  handleRealmCallback((RealmCallback) callback);
              } else if (callback instanceof AuthorizeCallback) {
                  handleAuthorizeCallback((AuthorizeCallback) callback);
              }
          }
      }
  
      private void handleNameCallback(NameCallback nc) {
          LOG.debug("handleNameCallback");
          userName = nc.getDefaultName();
          nc.setName(nc.getDefaultName());
      }
  
      private void handlePasswordCallback(PasswordCallback pc) {
          LOG.debug("handlePasswordCallback");
          if ("super".equals(this.userName) && System.getProperty(SYSPROP_SUPER_PASSWORD) != null) {
              // superuser: use Java system property for password, if available.
              pc.setPassword(System.getProperty(SYSPROP_SUPER_PASSWORD).toCharArray());
          } else if (credentials.containsKey(userName)) {
              pc.setPassword(credentials.get(userName).toCharArray());
          } else {
              LOG.warn("No password found for user: " + userName);
          }
      }
  
      private void handleRealmCallback(RealmCallback rc) {
          LOG.debug("handleRealmCallback: " + rc.getDefaultText());
          rc.setText(rc.getDefaultText());
      }
  
      private void handleAuthorizeCallback(AuthorizeCallback ac) {
          String authenticationID = ac.getAuthenticationID();
          LOG.info("Successfully authenticated client: authenticationID = " + authenticationID + " authorizationID = " + ac.getAuthorizationID());
  
          // if authorizationId is not set, set it to authenticationId.
          if (ac.getAuthorizationID() == null) {
              ac.setAuthorizedID(authenticationID);
          }
  
          // When authNid and authZid are not equal , authNId is attempting to impersonate authZid, We
          // add the authNid as the real user in reqContext's subject which will be used during authorization.
          if (!authenticationID.equals(ac.getAuthorizationID())) {
              LOG.info("Impersonation attempt  authenticationID = " + ac.getAuthenticationID() + " authorizationID = " + ac.getAuthorizationID());
              ReqContext.context().setRealPrincipal(new SaslTransportPlugin.User(ac.getAuthenticationID()));
          }
  
          ac.setAuthorized(true);
      }
  }
  