Role Based Access Control on MLS Systems Without Kernel Changes

Role based access control (RBAC) is attracting increasing attention as a security mechanism for both commercial and many military systems. This paper shows how RBAC can be implemented using the mechanisms available on traditional multi-level security systems that implement information flow policies. The construction from MLS to RBAC systems is significant because it shows that the enormous investment in MLS systems can be leveraged to produce RBAC systems. The method requires no changes to the existing MLS system kernel and allows implementation of hierarchical RBAC entirely through site configuration options. A single trusted process is used to map privileges of RBAC roles to MLS labels. Access is then mediated by the MLS kernel. Where C is the number of categories and d the depth of the role hierarchy, the number of roles that can be controlled is approximately ( C/d [over] C/2d )^d.