Growing numbers of users and many access policies that involve many different resource attributes in service-oriented environments cause various problems in protecting resource. This paper analyzes the relationships of resource attributes to user attributes based on access policies for Web services, and proposes a general attribute based role-based access control（GARBAC） model. The model introduces the notions of single attribute expression, composite attribute expression, and composition permission, defines a set of elements and relations among its elements and makes a set of rules, assigns roles to user by inputing user＇s attributes values. The model is a general access control model, can support more granularity resource information and rich access control policies, also can be used to wider application for services. The paper also describes how to use the GARBAC model in Web services environments.
