Fine-Grained Access Control with Object-Sensitive Roles

European Conference on Object-Oriented Programming (ECOOP 2009), Genova, Italy, July 6-10, 2009.
Jeffrey Fischer, Daniel Marino, Rupak Majumdar, Todd Millstein
Role-based access control (RBAC) is a common paradigm to ensure that users have sufficient rights to perform various system operations. In many cases though, traditional RBAC does not easily express application-level security requirements. For instance, in a medical records system it is difficult to express that doctors should only update the records of their own patients. Further, traditional RBAC frameworks like Java's Enterprise Edition rely solely on dynamic checks, which makes application code fragile and difficult to ensure correct.

We introduce Object-sensitive RBAC (ORBAC), a generalized RBAC model for object-oriented languages. ORBAC resolves the expressiveness limitations of RBAC by allowing roles to be parameterized by properties of the business objects being manipulated. We formalize and prove sound a dependent type system that statically validates a program's conformance to an ORBAC policy. We have implemented our type system for Java and have used it to validate fine-grained access control in the OpenMRS medical records system.