Review of Existing Analysis Tools for SELinux Security Policies: Challenges and a Proposed Solution

Abstract

Access control policy management is an increasingly hard problem from both the security point of view and the verification point of view. SELinux is a Linux Security Module (LSM) implementing a mandatory access control mechanism. SELinux integrates user identity, roles, and type security attributes for stating rules in security policies. As SELinux policies are developed and maintained by security administrators, they often become quite complex, and it is important to carefully analyze them in order to have high assurance of their correctness. There are many existing analysis tools for modeling and analyzing SELinux policies with the goal of answering specific safety and functionality questions. In this paper, we identify and highlight current gaps in these existing tools for SELinux policy analysis, and propose new tools and technologies with the potential to lead to significant improvements. The proposed solution includes adopting a certified access control policy language such as ACCPL (A Certified Access Core Policy Language). ACCPL comes with formal proofs of important properties, and our proposed solution includes adopting it to facilitate various analyses and proof of reasonability properties. ACCPL is general, and our goal is to design a certified domain-specific policy language based on it, specialized to our task.