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.calcite.avatica.server;
  
  import org.apache.calcite.avatica.AvaticaUtils;
  
  import org.eclipse.jetty.http.HttpHeader;
  import org.eclipse.jetty.security.ServerAuthException;
  import org.eclipse.jetty.security.authentication.DeferredAuthentication;
  import org.eclipse.jetty.server.Authentication;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  /**
   * Custom SpnegoAuthenticator which will still reponse with a WWW-Authentication: Negotiate
   * header if the client provides some other kind of authentication header.
   */
  @SuppressWarnings("deprecation")
  public class AvaticaSpnegoAuthenticator extends
      org.eclipse.jetty.security.authentication.SpnegoAuthenticator {
    private static final Logger LOG = LoggerFactory.getLogger(AvaticaSpnegoAuthenticator.class);
  
    @Override public Authentication validateRequest(ServletRequest request,
        ServletResponse response, boolean mandatory) throws ServerAuthException {
      final Authentication computedAuth = super.validateRequest(request, response, mandatory);
      try {
        return sendChallengeIfNecessary(computedAuth, request, response);
      } catch (IOException e) {
        throw new ServerAuthException(e);
      }
    }
  
    /**
     * Jetty has a bug in which if there is an Authorization header sent by a client which is
     * not of the Negotiate type, Jetty does not send the challenge to negotiate. This works
     * around that issue, forcing the challenge to be sent. Will require investigation on
     * upgrade to a newer version of Jetty.
     */
    Authentication sendChallengeIfNecessary(Authentication computedAuth, ServletRequest request,
        ServletResponse response) throws IOException {
      if (computedAuth == Authentication.UNAUTHENTICATED) {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse res = (HttpServletResponse) response;
  
        String header = req.getHeader(HttpHeader.AUTHORIZATION.asString());
        // We have an authorization header, but it's not Negotiate
        if (header != null && !header.startsWith(HttpHeader.NEGOTIATE.asString())) {
          LOG.debug("Client sent Authorization header that was not for Negotiate,"
              + " sending challenge anyways.");
          if (DeferredAuthentication.isDeferred(res)) {
            return Authentication.UNAUTHENTICATED;
          }
  
          res.setHeader(HttpHeader.WWW_AUTHENTICATE.asString(), HttpHeader.NEGOTIATE.asString());
          res.sendError(HttpServletResponse.SC_UNAUTHORIZED);
          return Authentication.SEND_CONTINUE;
        }
      } else if (computedAuth == Authentication.SEND_CONTINUE) {
        // CALCITE-4196 When we need to reply back to the client with the HTTP/401 challenge
        // we must make sure that we consume all of the data that the client has written. Otherwise,
        // the client will continue to write the data on a socket which we've already closed. This
        // would ultimately result in the client receiving a TCP Reset and seeing a "Broken pipe"
        // exception in their client application.
        HttpServletRequest req = (HttpServletRequest) request;
        AvaticaUtils.skipFully(req.getInputStream());
      }
      return computedAuth;
    }
  }
  
  // End AvaticaSpnegoAuthenticator.java
  