|Home > Apache Geronimo v2.2 > Documentation > Configuring and administering > Administering Security > Configuring login modules|
Due to some limitations in the default configuration implementation, Geronimo replaces login.conf entirely with one that is configured via GenericSecurityRealm GBeans. This lets you deploy the security realm you need with your application and allows you to dynamically add the login module classes to the server as needed. You can also distinguish between the same principal when created by different login modules or security realms.
A typical security realm GBean looks like this:
Most of the innards here are similar to the login.conf file, converted to xml. You can include as many login-module elements as you need. The control flag is specified as an attribute of this element. Each login module needs a login-domain-name that is unique within the security realm. You can include as many options as you need. Geronimo will supply these options for all login modules so that the login modules can use them without declaring them in the configuration:
If you specify wrap-principals as false, your login module will work as usual and only its principals will get into the Subject. However if you specify wrap-principals as true, Geronimo will also add principals that wrap your principals and include the login-domain-name and realm-name of the login module and security realm that created the principal. This enables your role-principal mapping to distinguish between the "same" principal that comes from different sources. For instance, if you had two ldap servers where the groups had the same names but the meaning was different (perhaps users from different departments) you can wrap the principals yet still distinguish the same group based on the different realms. However, in order to distinguish principals in this way, we supply each login module with its own empty Subject object. Therefore ,a later login module cannot access the principals added to a Subject by an earlier login module. If you need to share information between login modules and also wrap principals, you must use the shared state map and not the Subject.
A security realm has a 'global' attribute. If set to true, it is available to every application and to all ejbs. If set to false or omitted, it is only available to web applications that include the plugin containing the security realm as a dependency (or web applications that include the security realm definition themselves). Note that any security realm to be used by ejbs MUST be marked global. The reason for non-global security realms is to allow deploying multiple realms with the same name without conflicts while distinguishing between them using the dependency directed acyclic graph.