CAS authentication and limiting access for specified users

I'm using CAS (Central Authentication Service) from Jasig in a client JSF app running on tomcat 6 server. I would like to limit the access to the app just for the users specified in my database rather than all the users which can be authenticated using that CAS service. When the user attempts to log in, I need to check if his username is also in my database's table user and if it is - allow the access to the app. Otherwise, I would like to redirect user to a page "You don't have permission to access this part of the application". So I need authorization as well. Is there a good way to authorize the us开发者_运维知识库ers in jsf 2.0? Thanks in advance for any help/suggestions.

Sounds like you need to design a custom Authentication Handler class in CAS. In theory, your handler would extend this [1], perform all the necessary checks and database look ups and will then be able to return a signal that indicates whether or not the user could authN.

You should then reference your custom handler in the deploerConfigContext.xml file.

For displaying the message, you could either throw an exception with the proper messages code, such that the message would appear above the login form, or you could alter the spring webflow and generate a new view-state which the user would be redirected to, if they fail to get access. The first approach is much easier to implement.

Another approach would be to take advantage of the isUserInRole() method [2] using the persondir api.

[1] http://developer.jasig.org/projects/cas/cas-server-core/cas-server/cas-server-core/apidocs/org/jasig/cas/authentication/handler/support/AbstractUsernamePasswordAuthenticationHandler.html

[2] https://wiki.jasig.org/pages/viewpage.action?pageId=47874068