多级安全数据库的安全策略需要各种模型来表达,访问控制模型是其中之一.强制访问控制(MAC)模型保证多级数据库中的信息流动符合系统的安全策略.利用基于角色的访问控制(RBAC)来实现MAC能方便多级安全数据库的权限管理.提出了一种MAC与RBAC的综合模型,定义了多级角色与内部角色的概念,并给出了综合模型中经过修改后的操作,使得系统能自动地完成符合强制访问控制策略的用户权限的管理.该模型方便了管理员的权限管理,适合用户较多,安全层次比较复杂的多级关系数据库系统.最后给出了模型的部分实现机制.

Security policy of multilevel security DBMS is expressed by many models.One of them is access control model.Mandatory Access Control (MAC) model guarantees that information flow in multilevel databases is inaccordance with security policy.Role-Based Access Control can simplify administration of privileges in multilevel databases.This paper proposes an integrated model of RBAC and MAC.Multilevel role and internal role are defined,and some modified operations in the model are presented.Administration of privileges under MAC policy is done by system automatically.The integrated model can simplify administration of privileges,and is appropriate for multilevel relation database system which has many users or complex security levels.Some implementing mechanisms of the model are provided.