1. A method of controlling access to computer system resources based on permissions, comprising: receiving a request for access to a computer system resource; determining if a superclass permission of a required permission is present in each protection domain of an access control context; adding the required permission to a permission collection if the superclass permission of the required permission is present in each protection domain of the access control context; and granting access to the resource if the superclass permission of the required permission is present in each protection domain of the access control context.