Using the Java Authentication and Authorization Service programming model for Web authentication

WebSphere Application Server supports the Java 2 Platform, Enterprise Edition (J2EE) declarative security model. You can define the authentication and access control policy using the J2EE deployment descriptor. You can further stack custom login modules to customize the WAS authentication mechanism.

 

Before you begin

A custom login module can perform principal and credential mapping, custom security token and custom credential-processing, and error-handling among other possibilities. Typically, you do not need to use application code to perform authentication function. Use the programming techniques that are described in this section if you have to perform authentication function in application code. For example, if you have applications that programmed to the SSOAuthenticator helper function, you can use the following programming interface. The SSOAuthenticator helper function was deprecated starting with WebSphere Application Server Version 4.0. Use declarative security as a rule; use the techniques that are described in this section as a last resort.

 

About this task

When the Lightweight Third-Party Authentication (LTPA) mechanism single sign-on (SSO) option is enabled, the Web client login session is tracked by an LTPA SSO token cookie after successful login. At logout, this token is deleted to terminate the login session, but the server-side subject is not deleted. When you use the declarative security model, the WebSphere Application Server Web container performs client authentication and login session management automatically. You can perform authentication in application code by setting a login page without a J2EE security constraint and by directing client requests to your login page first. Your login page can use the Java Authentication and Authorization Service (JAAS) programming model to perform authentication. To enable WAS Web login modules to generate SSO cookies, use the following steps.

 

Procedure

  1. Create a new system login JAAS configuration on the Global Security panel.
  2. Manually clone the WEB_INBOUND login configuration and give it a new alias. To clone the login configuration, you can click New, enter a name for the configuration, click Apply, and click JAAS login modules under Additional properties. Click New and configure the JAAS login module. For more information, see Login module settings for Java Authentication and Authorization Service . WAS Web container uses the WEB_INBOUND login configuration to authenticate Web clients. Changing the WEB_INBOUND login configuration affects all Web applications in the cell. You should create your own login configuration by cloning the contents of the WEB_INBOUND login configuration.
  3. [V6.0] [Version 6.0.1] Select the ltpaLoginModule login module and click Custom properties. There are two login modules defined in your login configuration: ltpaLoginModule and wsMapDefaultInboundLoginModule.
  4. Select the wsMapDefaultInboundLoginModule login module and click Custom properties. There are two login modules defined in your login configuration: ltpaLoginModule and wsMapDefaultInboundLoginModule.
  5. Add a login property name cookie with a value of true. The two login modules are enabled to generate LTPA SSO cookies. Do not add the cookie login option to the original WEB_INBOUND login configuration. The cookie option defined at the ltpaLoginModule applies to both login modules in your login configuration.
  6. Optional: Set an order for your custom LoginModule(s) in the new login configuration (optional).
  7. Use your login page for programmatic login by perform a JAAS LoginContext.login using your newly defined login configuration. After a successful login, either the ltpaLoginModule or the wsMapDefaultInboundLoginModule generates an LTPA SSO cookie upon a successful authentication. Exactly which LoginModule generates the SSO cookie depends on many factors, including system authentication configuration and runtime condition (which is beyond the scope of this section).
  8. Call the modified WSSubject.setRunAsSubject method to add the subject to the authentication cache. The subject must be a WebSphere Application Server JAAS subject created by LoginModule. Adding the subject to the authentication cache recreates a subject from SSO token.
  9. Use your programmatic logout page to revoke SSO cookies by invoking the revokeSSOCookies method from the WSSecurityHelper class. The term cookies is used because WAS Release 5.1.1 (and later) release supports a new LTPA SSO token with a different encryption algorithm, but can be configured to generate the original LTPA SSO token for backward compatibility. Note that the subject is still in the authentication cache and only the SSO cookies are revoked.

Example

Use the following code sample to perform authentication:
Suppose you wrote a LoginServlet.java:

 Import com.ibm.wsspi.security.auth.callback.WSCallbackHandlerFactory;
 Import com.ibm.websphere.security.auth.WSSubject;

 public Object login(HttpServletRequest req, HttpServletResponse res) 
 throws ServletException {

 PrintWriter out = null;
 try {
  out =  res.getWriter();
      res.setContentType("text.html");
 } catch (java.io.IOException e){
  // Error handling
 }

 Subject subject = null;
 try {
 LoginContext lc = new LoginContext("system.Your_login_configuration",
WSCallbackHandlerFactory.getInstance().getCallbackHandler(
userid, null, password, req, res, null));
  lc.login();
  subject = lc.getSubject();
      WSSubject.setRunAsSubject(subject);
 } catch(Exception e) {
  // catch all possible exceptions if you want or handle them separately
  out.println("Exception in LoginContext login + Exception = " +
 e.getMessage());
  throw new ServletException(e.getMessage());
 }

The following is sample code to revoke the SSO cookies upon a programming logout:


The LogoutServlet.java:

 public void logout(HttpServletRequest req, HttpServletResponse res,
 Object retCreds)  throws ServletException {
   PrintWriter out =null;
   try {
    out =  res.getWriter();
        res.setContentType("text.html");
   } catch (java.io.IOException e){
   // Error Handling
   }
   try {
     WSSecurityHelper.revokeSSOCookies(req, res);
   } catch(Exception e) {
    // catch all possible exceptions if you want or handle them separately
    out.println("JAASLogoutServlet: logout Exception = " + e.getMessage());
    throw new ServletException(e);
   }
  }

 

What to do next

For more information on JAAS authentication, refer to Developing programmatic logins with the Java Authentication and Authorization Service. For more information on the AuthenLoginModule login module, refer to Example: Customizing a server-side Java Authentication and Authorization Service authentication and login configuration.