CXF ships a useful utility JAASLoginInterceptor which greatly simplifies the process of interacting with the JAAS subsystem and creating a current SecurityContext encapsulating the information about a user principal and roles which will be used for making authorization decisions. See this post for some more information.
When working with Apache Karaf, the simple way to get roles distinguished from a user principal is to configure the Karaf JAAS context such that role names start from a prefix such as "role_" and then let JAASLoginInterceptor know about it using a now deprecated "rolePrefix" property.
However when the existing stores containing the info about roles are used this simple technique may not work given that all sort of naming conventions can be used which may not 'managed' by a rolePrefix property. It makes it trickier to capture roles given that in Karaf the classes representing roles and user principals implement only a single Principal marker interface.
So in 2.5.0 what you can do in such cases is to use new roleClassifier and roleClassifierType properties to let JAASLoginInterceptor know how to get to the roles. Please see this section for an example (the updated content will be visible shortly). This enhancement came after the conversation with my Talend colleague Andrei Shakirin.
Additionally, Aki Yoshida enhanced the interceptor to better cope with the containers providing custom callbacks, for example, it will work perfectly with Jetty providing ObjectCallback instead of javax.security.auth.callback.PasswordCallback.
Finally note that SecurityContexts set by JAASLoginInterceptor on the current CXF message implement LoginSecurityContext. This one can be very handy for getting say Spring SecurityContexts populated, for doing the custom authorization based on the list of provided roles and using the underlying Subject returned from the JAAS subsystem as needed.
If you are asking at this stage, hmm, do I really need to continue using the servlet security, then you are most likely on the right track :-)