Use the JAAS programming model for web authentication
WebSphere Application Server supports the Java EE declarative security model. We can define the authentication and access control policy using the Java EE deployment descriptor. We can further stack custom login modules to customize the WAS authentication mechanism.
A custom login module can perform principal and credential mapping, custom security token and custom credential-processing, and error-handling among other possibilities. Typically, we do not need to use application code to perform authentication function. Use the programming techniques described in this section if we have to perform authentication function in application code. Use declarative security as a rule; use the techniques described in this section as a last resort.
When the 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 we use the declarative security model, the WAS web container performs client authentication and login session management automatically. We can perform authentication in application code by setting a login page without a Java EE security constraint and by directing client requests to your login page first. Your login page can use the JAAS programming model to perform authentication. To enable WAS web login modules to generate SSO cookies, use the following steps.
Tasks
- Create a new system login JAAS configuration. To access the panel, click...
- Security | Global security | JAAS | System logins
- Manually clone the WEB_INBOUND login configuration, and give it a new alias.
To clone the login configuration, click New, enter a name for the configuration, click Apply, then click JAAS login modules under Additional properties. Click New and configure the JAAS login module.
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. We should create our own login configuration by cloning the contents of the WEB_INBOUND login configuration.
- Select the wsMapDefaultInboundLoginModule login module and click Custom properties. There are two login modules defined in your login configuration: ltpaLoginModule and wsMapDefaultInboundLoginModule.
- 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.
- Stack our custom LoginModule(s) in the new login configuration (optional).
- Use your login page for programmatic login by perform a JAAS LoginContext.login using the 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).
- Call the modified WSSubject.setRunAsSubject method to add the subject to the authentication cache.
The subject must be a WAS JAAS subject created by LoginModule. Adding the subject to the authentication cache recreates a subject from SSO token.
- 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 v5.1.1 and later support 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.
Deprecated feature: The revokeSSOCookies(HttpServletRequest, HttpServletResponse) method from the WSSecurityHelper class is deprecated. Use the functionality provided by the Java Servlet-3.0 logout() method. Read Servlet security methods.depfeat
Example
Use the following code sample to perform authentication.
If we set the password for the WSCallbackHandlerFactoryset factory class for getting handlers to null, as is done in the following example, we allow identity assertion without a password..
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 we 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 we 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 JAAS. For more information on the AuthenLoginModule login module, refer to Example: Customizing a server-side Java Authentication and Authorization Service authentication and login configuration.
Subtopics
- Develop custom login modules for a system login configuration for JAAS
For WAS, multiple Java Authentication and Authorization Service (JAAS) plug-in points exist for configuring system logins. WAS uses system login configurations to authenticate incoming requests, outgoing requests, and internal server logins.
Related: