14.2 Introduction

The TrustedBSD MAC framework provides a mechanism to allow the compile-time or run-time extension of the kernel access control model. New system policies may be implemented as kernel modules and linked to the kernel; if multiple policy modules are present, their results will be composed. While the framework is intended to support a variety of access control models, its design was derived from the requirements of a set of specific access control models required for the TrustedBSD and CBOSS Projects. This includes support for fixed and floating label Biba integrity policies, the MLS confidentiality policy, the Type Enforcement rule-based access control policy, and the ability to support layering of the NSA FLASK framework above the TrustedBSD MAC framework. This document describes the rough architecture of the framework, with the understanding that this is a work-in-progress and may change subtantially as requirements evolve.