14.8. 在应用程序里使用第三方的验证系统

你可以在 JBoss EAP 里集成第三方安全系统。这些系统通常是基于令牌的。外部的系统执行验证并将一个令牌通过请求头部回传给 Web 应用程序。这通常被称为周边验证(perimeter authentication)。要在应用程序里配置周边验证,请添加一个自定义验证阀。如果第三方提供者提供了验证阀,请确保将其放入 classpath 并遵循下面例子里的步骤,以及参考第三方验证模块的文档。

注意

JBoss EAP 6 已经改变了配置阀的位置。它不再位于 context.xml 里,它现在直接在 jboss-web.xml 描述符里进行配置。context.xml 现在已被忽略了。

例 14.1. 基本的验证阀

<jboss-web>
  <valve>
    <class-name>org.jboss.security.negotiation.NegotiationAuthenticator</class-name>
  </valve>
</jboss-web>

这个阀用于基于 Kerberos 的 SSO。它也展示了为 web 应用程序指定第三方验证器的多数简单模式。

例 14.2. 带有头部属性集的自定义阀

<jboss-web>
  <valve>
    <class-name>org.jboss.web.tomcat.security.GenericHeaderAuthenticator</class-name>
    <param>
      <param-name>httpHeaderForSSOAuth</param-name>
      <param-value>sm_ssoid,ct-remote-user,HTTP_OBLIX_UID</param-value>
    </param>
    <param>
      <param-name>sessionCookieForSSOAuth</param-name>
      <param-value>SMSESSION,CTSESSION,ObSSOCookie</param-value>
    </param>
  </valve>
</jboss-web>

这个例子展示了如何在阀上设置自定义的属性。验证器检查头部 ID 和会话密钥的存在,并作为用户名和密码值传入驱动安全层的 JAAS 框架。你需要一个自定义的 JAAS 登录模块来处理用户名和密码并用正确的角色传播主题。而如果没有对应配置值的头部值,普通的基于表单的验证模式将被使用。
编写自定义验证器

编写自定义的验证器超出了本文档的范畴。然而,下面的 Java 代码可以作为例子参考。

例 14.3. GenericHeaderAuthenticator.java

/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
 
package org.jboss.web.tomcat.security;

import java.io.IOException;
import java.security.Principal;
import java.util.StringTokenizer;

import javax.management.JMException;
import javax.management.ObjectName;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.catalina.Realm;
import org.apache.catalina.Session;
import org.apache.catalina.authenticator.Constants;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.deploy.LoginConfig;
import org.jboss.logging.Logger;

import org.jboss.as.web.security.ExtendedFormAuthenticator;

/**
 * JBAS-2283: Provide custom header based authentication support
 * 
 * Header Authenticator that deals with userid from the request header Requires
 * two attributes configured on the Tomcat Service - one for the http header
 * denoting the authenticated identity and the other is the SESSION cookie
 * 
 * @author <a href="mailto:Anil.Saldhana@jboss.org">Anil Saldhana</a>
 * @author <a href="mailto:sguilhen@redhat.com">Stefan Guilhen</a>
 * @version $Revision$
 * @since Sep 11, 2006
 */
public class GenericHeaderAuthenticator extends ExtendedFormAuthenticator {
  protected static Logger log = Logger
      .getLogger(GenericHeaderAuthenticator.class);

  protected boolean trace = log.isTraceEnabled();

  // JBAS-4804: GenericHeaderAuthenticator injection of ssoid and
  // sessioncookie name.
  private String httpHeaderForSSOAuth = null;

  private String sessionCookieForSSOAuth = null;

  /**
   * <p>
   * Obtain the value of the <code>httpHeaderForSSOAuth</code> attribute. This
   * attribute is used to indicate the request header ids that have to be
   * checked in order to retrieve the SSO identity set by a third party
   * security system.
   * </p>
   * 
   * @return a <code>String</code> containing the value of the
   *         <code>httpHeaderForSSOAuth</code> attribute.
   */
  public String getHttpHeaderForSSOAuth() {
    return httpHeaderForSSOAuth;
  }

  /**
   * <p>
   * Set the value of the <code>httpHeaderForSSOAuth</code> attribute. This
   * attribute is used to indicate the request header ids that have to be
   * checked in order to retrieve the SSO identity set by a third party
   * security system.
   * </p>
   * 
   * @param httpHeaderForSSOAuth
   *            a <code>String</code> containing the value of the
   *            <code>httpHeaderForSSOAuth</code> attribute.
   */
  public void setHttpHeaderForSSOAuth(String httpHeaderForSSOAuth) {
    this.httpHeaderForSSOAuth = httpHeaderForSSOAuth;
  }

  /**
   * <p>
   * Obtain the value of the <code>sessionCookieForSSOAuth</code> attribute.
   * This attribute is used to indicate the names of the SSO cookies that may
   * be present in the request object.
   * </p>
   * 
   * @return a <code>String</code> containing the names (separated by a
   *         <code>','</code>) of the SSO cookies that may have been set by a
   *         third party security system in the request.
   */
  public String getSessionCookieForSSOAuth() {
    return sessionCookieForSSOAuth;
  }

  /**
   * <p>
   * Set the value of the <code>sessionCookieForSSOAuth</code> attribute. This
   * attribute is used to indicate the names of the SSO cookies that may be
   * present in the request object.
   * </p>
   * 
   * @param sessionCookieForSSOAuth
   *            a <code>String</code> containing the names (separated by a
   *            <code>','</code>) of the SSO cookies that may have been set by
   *            a third party security system in the request.
   */
  public void setSessionCookieForSSOAuth(String sessionCookieForSSOAuth) {
    this.sessionCookieForSSOAuth = sessionCookieForSSOAuth;
  }

  /**
   * <p>
   * Creates an instance of <code>GenericHeaderAuthenticator</code>.
   * </p>
   */
  public GenericHeaderAuthenticator() {
    super();
  }

  public boolean authenticate(Request request, HttpServletResponse response,
      LoginConfig config) throws IOException {
    log.trace("Authenticating user");

    Principal principal = request.getUserPrincipal();
    if (principal != null) {
      if (trace)
        log.trace("Already authenticated '" + principal.getName() + "'");
      return true;
    }

    Realm realm = context.getRealm();
    Session session = request.getSessionInternal(true);

    String username = getUserId(request);
    String password = getSessionCookie(request);

    // Check if there is sso id as well as sessionkey
    if (username == null || password == null) {
      log.trace("Username is null or password(sessionkey) is null:fallback to form auth");
      return super.authenticate(request, response, config);
    }
    principal = realm.authenticate(username, password);

    if (principal == null) {
      forwardToErrorPage(request, response, config);
      return false;
    }

    session.setNote(Constants.SESS_USERNAME_NOTE, username);
    session.setNote(Constants.SESS_PASSWORD_NOTE, password);
    request.setUserPrincipal(principal);

    register(request, response, principal, HttpServletRequest.FORM_AUTH,
        username, password);
    return true;
  }

  /**
   * Get the username from the request header
   * 
   * @param request
   * @return
   */
  protected String getUserId(Request request) {
    String ssoid = null;
    // We can have a comma-separated ids
    String ids = "";
    try {
      ids = this.getIdentityHeaderId();
    } catch (JMException e) {
      if (trace)
        log.trace("getUserId exception", e);
    }
    if (ids == null || ids.length() == 0)
      throw new IllegalStateException(
          "Http headers configuration in tomcat service missing");

    StringTokenizer st = new StringTokenizer(ids, ",");
    while (st.hasMoreTokens()) {
      ssoid = request.getHeader(st.nextToken());
      if (ssoid != null)
        break;
    }
    if (trace)
      log.trace("SSOID-" + ssoid);
    return ssoid;
  }

  /**
   * Obtain the session cookie from the request
   * 
   * @param request
   * @return
   */
  protected String getSessionCookie(Request request) {
    Cookie[] cookies = request.getCookies();
    log.trace("Cookies:" + cookies);
    int numCookies = cookies != null ? cookies.length : 0;

    // We can have comma-separated ids
    String ids = "";
    try {
      ids = this.getSessionCookieId();
      log.trace("Session Cookie Ids=" + ids);
    } catch (JMException e) {
      if (trace)
        log.trace("checkSessionCookie exception", e);
    }
    if (ids == null || ids.length() == 0)
      throw new IllegalStateException(
          "Session cookies configuration in tomcat service missing");

    StringTokenizer st = new StringTokenizer(ids, ",");
    while (st.hasMoreTokens()) {
      String cookieToken = st.nextToken();
      String val = getCookieValue(cookies, numCookies, cookieToken);
      if (val != null)
        return val;
    }
    if (trace)
      log.trace("Session Cookie not found");
    return null;
  }

  /**
   * Get the configured header identity id in the tomcat service
   * 
   * @return
   * @throws JMException
   */
  protected String getIdentityHeaderId() throws JMException {
    if (this.httpHeaderForSSOAuth != null)
      return this.httpHeaderForSSOAuth;
    return (String) mserver.getAttribute(new ObjectName(
        "jboss.web:service=WebServer"), "HttpHeaderForSSOAuth");
  }

  /**
   * Get the configured session cookie id in the tomcat service
   * 
   * @return
   * @throws JMException
   */
  protected String getSessionCookieId() throws JMException {
    if (this.sessionCookieForSSOAuth != null)
      return this.sessionCookieForSSOAuth;
    return (String) mserver.getAttribute(new ObjectName(
        "jboss.web:service=WebServer"), "SessionCookieForSSOAuth");
  }

  /**
   * Get the value of a cookie if the name matches the token
   * 
   * @param cookies
   *            array of cookies
   * @param numCookies
   *            number of cookies in the array
   * @param token
   *            Key
   * @return value of cookie
   */
  protected String getCookieValue(Cookie[] cookies, int numCookies,
      String token) {
    for (int i = 0; i < numCookies; i++) {
      Cookie cookie = cookies[i];
      log.trace("Matching cookieToken:" + token + " with cookie name="
          + cookie.getName());
      if (token.equals(cookie.getName())) {
        if (trace)
          log.trace("Cookie-" + token + " value=" + cookie.getValue());
        return cookie.getValue();
      }
    }
    return null;
  }
}