CAS客户端证书认证登录

前端时间需要实现公司内网证书自动登录CAS.

由于对CAS的底层还不是特别了解所以学习了下,看了下源码.

 

这里我由上而下的讲解实现的过程.

 

1.Web Flow

我们都知道CAS目前使用了Spring Web Flow,

在CAS中Spring Web Flow的配置文件为login-webflow.xml

里面主要配置了登录的流程.这个如果用图来表示的话那应该是一个状态图,

一些节点会有一些判断然后会有不同的分支.

这里增加了startX509Authenticate这个节点,当需要登录的时候首先进入这个节点来验证,如果这里验证不成功的话才会进入普通的登录界面.负责直接登录成功,或者登录失败.

 

修改后的配置文件如下:

<?xml version="1.0" encoding="UTF-8"?>
    <flow xmlns="http://www.springframework.org/schema/webflow"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="
              http://www.springframework.org/schema/webflow
              http://www.springframework.org/schema/webflow/spring-webflow-1.0.xsd">

	<start-state idref="initialFlowSetup"/>

	<action-state id="initialFlowSetup">
		<action bean="initialFlowSetupAction" />
		<transition on="success" to="ticketGrantingTicketExistsCheck" />
	</action-state>
	
	<decision-state id="ticketGrantingTicketExistsCheck">
		<if test="${flowScope.ticketGrantingTicketId != null}" then="hasServiceCheck" else="gatewayRequestCheck" />
	</decision-state>
    
	<decision-state id="gatewayRequestCheck">
		<if test="${externalContext.requestParameterMap['gateway'] != '' &amp;&amp; externalContext.requestParameterMap['gateway'] != null &amp;&amp; flowScope.service != null}" then="redirect" else="startX509Authenticate" />
	</decision-state>
	
	<decision-state id="hasServiceCheck">
		<if test="${flowScope.service != null}" then="renewRequestCheck" else="viewGenericLoginSuccess" />
	</decision-state>
	
	<decision-state id="renewRequestCheck">
		<if test="${externalContext.requestParameterMap['renew'] != '' &amp;&amp; externalContext.requestParameterMap['renew'] != null}" then="startX509Authenticate" else="generateServiceTicket" />
	</decision-state>
	
	<decision-state id="warn">
		<if test="${flowScope.warnCookieValue}" then="showWarningView" else="redirect" />
	</decision-state>
	

	<action-state id="startX509Authenticate">
		<action bean="x509Check" />
		<transition on="success" to="sendTicketGrantingTicket" />
		<transition on="error" to="viewLoginForm" />
	</action-state>

	<view-state id="viewLoginForm" view="casLoginView">
			<render-actions>
			<action bean="authenticationViaFormAction" method="setupForm"/>
			<action bean="authenticationViaFormAction" method="referenceData"/>
		</render-actions>
		<transition on="submit" to="bindAndValidate" />
	</view-state>
	
	<action-state id="bindAndValidate">
		<action bean="authenticationViaFormAction" />
		<transition on="success" to="submit" />
		<transition on="error" to="viewLoginForm" />
	</action-state>
	
	<action-state id="submit">
		<action bean="authenticationViaFormAction" method="submit" />
		<transition on="warn" to="warn" />
		<transition on="success" to="sendTicketGrantingTicket" />
		<transition on="error" to="viewLoginForm" />
	</action-state>
	
	<action-state id="sendTicketGrantingTicket">
		<action bean="sendTicketGrantingTicketAction" />
		<transition on="success" to="serviceCheck" />
	</action-state>

	<decision-state id="serviceCheck">
		<if test="${flowScope.service != null}" then="generateServiceTicket" else="viewGenericLoginSuccess" />
	</decision-state>
	
	<action-state id="generateServiceTicket">
		<action bean="generateServiceTicketAction" />
		<transition on="success" to ="warn" />
		<transition on="error" to="viewLoginForm" />
		<transition on="gateway" to="redirect" />
	</action-state>

	<end-state id="viewGenericLoginSuccess" view="casLoginGenericSuccessView" />
	<end-state id="showWarningView" view="casLoginConfirmView" />
	<end-state id="redirect" view="bean:alibabaDynamicRedirectViewSelector" />
	<end-state id="viewServiceErrorView" view="viewServiceErrorView" />
        <end-state id="viewServiceSsoErrorView" view="viewServiceSsoErrorView" />

	<global-transitions>
		<transition to="viewServiceErrorView" on-exception="org.springframework.webflow.execution.repository.NoSuchFlowExecutionException" />
        <transition to="viewServiceSsoErrorView" on-exception="org.jasig.cas.services.UnauthorizedSsoServiceException" />
		<transition to="viewServiceErrorView" on-exception="org.jasig.cas.services.UnauthorizedServiceException" />
	</global-transitions>
</flow>

 

 

2.从X509Check着手

从上面的配置文件我们可看出startX509Authenticate这个节点对应的Bean是x509Check

那么我们需要增加这样的一个Bean

我们在cas-servlet.xml这个配置文件中增加这个类的配置,因为CAS自带了证书认证的Action

<bean id="x509Check" class="org.jasig.cas.adaptors.x509.web.flow.X509CertificateCredentialsNonInteractiveAction"
		p:centralAuthenticationService-ref="centralAuthenticationService"/>

 这里不得不插进来说一下,在执行的时候是怎么个机制了.

 

当有一个请求过来之后,web flow安排对应节点的Action 来处理,

Action便通过它的centralAuthenticationService 来进行createTicketGrantingTicket,传递的参数是credentials.

centralAuthenticationService ,即org.jasig.cas.CentralAuthenticationServiceImpl这个类.

在颁发TGT之前先通过自己的authenticationManager来验证当前传递过来的credentials是否合法.

来到authenticationManager 的家中之后,使用什么来验证credentials呢,对了各种authenticationHandlers该上场了,这些authenticationHandlers 们也都是在配置authenticationManager的时候xml配置进去的.这里会选择一个能够处理当前credential的authenticationHandler来进行验证工作(authenticationHandler.supports(credentials)).也就是这些处理器都需要实现supports这个方法.

如果验证成功了,我们需要将一些标示信息带到cas的client端阿,那边需要这个信息.

所以验证之后,credentialsToPrincipalResolvers 们上场了,他们能够很好的带出需要传回给cas client的信息.

 

经过上面的分析,我们需要将我们自己的Handler和credentialsToPrincipalResolvers添加到authenticationManager的配置中

	<bean id="authenticationManager"
	class="org.jasig.cas.authentication.AuthenticationManagerImpl">
		<property name="credentialsToPrincipalResolvers">
			<list>
				<bean class="org.jasig.cas.authentication.principal.UsernamePasswordCredentialsToPrincipalResolver" />
				<bean class="org.jasig.cas.authentication.principal.HttpBasedServiceCredentialsToPrincipalResolver" />
				<bean class="org.jasig.cas.adaptors.x509.authentication.principal.X509CertificateCredentialsToDNEmailPrincipalResolver"/>
			</list>
		</property>
		<property name="authenticationHandlers">
			<list>
				<bean class="org.jasig.cas.authentication.handler.support.HttpBasedServiceCredentialsAuthenticationHandler"
					p:httpClient-ref="httpClient" />
				<ref bean="dynamicAuthenticationHandler" />
				<ref bean="x509CredentialsAuthenticationHandler"/>
			</list>
		</property>
	</bean>

  x509CredentialsAuthenticationHandler这个CAS自带了,但是我们需要返回到CAS Client的为证书的邮箱,而CAS没有提供这样的Resolver,所以我自己写了一个从证书中取得email的X509CertificateCredentialsToDNEmailPrincipalResolver

 

当然这里引用到的类也需要在Spring中进行配置

	<bean id="x509CredentialsAuthenticationHandler" class="org.jasig.cas.adaptors.x509.authentication.handler.support.X509CredentialsAuthenticationHandler" >
	<property name="trustedIssuerDnPattern" value="CN=intranet.+"/>
	</bean>

 

这样便可以了.

 

3.Tomcat配置

 

接下来我们便需要将CA的证书加入到servlet容器的TrustStore中.并开启客户端认证.

	<Connector port="8447" maxHttpHeaderSize="8192"
               maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
               enableLookups="false" disableUploadTimeout="true"
               acceptCount="100" scheme="https" secure="true"
               clientAuth="want" sslProtocol="TLS" 
               keystoreFile="conf/ssl/keystore.jks" keystorePass="changeit"
			   truststoreFile="conf/ssl/keystore.jks" truststorePass="changeit"
    />

 clientAuth="want"配置成want表示不强求,如果有则使用,配置成true的话那就必须通过证书,否则直接返回404

我们这里为了如果没有证书还可以进去普通登录页面,所以采取了want这个参数.

 

启动CAS ,一切OK了.

 

---------------------------------------------------------------------------------------------

PS:附上从证书中获取Email的代码

package org.jasig.cas.adaptors.x509.authentication.principal;

import java.security.cert.X509Certificate;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.bouncycastle.asn1.x509.X509NameTokenizer;

public class X509CertificateCredentialsToDNEmailPrincipalResolver extends AbstractX509CertificateCredentialsToPrincipalResolver {

    public static final String EMAIL = "rfc822name";
    public static final String EMAIL1 = "email";
    public static final String EMAIL2 = "EmailAddress";
    public static final String EMAIL3 = "E";
    private static final String[] EMAILIDS = { EMAIL, EMAIL1, EMAIL2, EMAIL3 };
    protected final Log log = LogFactory.getLog(this.getClass());

	@Override
	protected String resolvePrincipalInternal(X509Certificate certificate) {
		String email =  getEmailFromDN(certificate.getSubjectDN().getName());
		dynamicAuthenticationHandler.reload();
		if(email!=null){
			return email;
		}
		return null;
	}
	


	/**
     * Convenience method for getting an email address from a DN.
     * @param dn the DN
     * @return the found email address, or <code>null</code> if none is found
     */
    public  String getEmailFromDN(String dn) {
        log.info(">getEmailFromDN(" + dn + ")");
        String email = null;
        for (int i = 0; (i < EMAILIDS.length) && (email == null); i++) {
            email = getPartFromDN(dn, EMAILIDS[i]);
        }

        log.error("<getEmailFromDN(" + dn + "): " + email);

        return email;
    }
    
    /**
     * Gets a specified part of a DN. Specifically the first occurrence it the DN contains several
     * instances of a part (i.e. cn=x, cn=y returns x).
     *
     * @param dn String containing DN, The DN string has the format "C=SE, O=xx, OU=yy, CN=zz".
     * @param dnpart String specifying which part of the DN to get, should be "CN" or "OU" etc.
     *
     * @return String containing dnpart or null if dnpart is not present
     */
    public  String getPartFromDN(String dn, String dnpart) {
        log.debug(">getPartFromDN: dn:'" + dn + "', dnpart=" + dnpart);

        String part = null;

        if ((dn != null) && (dnpart != null)) {
            String o;
            dnpart += "="; // we search for 'CN=' etc.

            X509NameTokenizer xt = new X509NameTokenizer(dn);

            while (xt.hasMoreTokens()) {
                o = xt.nextToken();

                //log.debug("checking: "+o.substring(0,dnpart.length()));
                if ((o.length() > dnpart.length()) &&
                    o.substring(0, dnpart.length()).equalsIgnoreCase(dnpart)) {
                    part = o.substring(dnpart.length());

                    break;
                }
            }
        }

        log.debug("<getpartFromDN: resulting DN part=" + part);

        return part;
    } //getPartFromDN

}

 

 

评论

4 楼 jackonline 2013-09-24  

貌似不能用了

3 楼 雁行 2012-11-13  

搭建环境后，感觉客户端证书client.cer没有被用到，原来是服务端没有开启，受教了

2 楼 musenl 2012-08-27  

dynamicAuthenticationHandler.reload()是哪个类的啊

1 楼 infante_yin 2010-08-19  

你好！可以配置多种证书吗？