Integrating Flexible Support for Security Policies into the Linux Operating System

TLDR

Current mainstream operating systems lack adequate protection for confidentiality and integrity, and traditional mandatory access control (MAC) has limited adoption; the NSA and Secure Computing Corporation addressed this by developing the flexible Flask MAC architecture. This paper presents the architecture, mechanisms, API, policy configuration, and performance of Security-Enhanced Linux (SELinux). The NSA implemented Flask in Linux to create SELinux, and NAI Labs provided an example policy configuration to illustrate its benefits and serve as a foundation for others.

Abstract

The protection mechanisms of current mainstream operating systems are inadequate to support confidentiality and integrity requirements for end systems. Mandatory access control (MAC) is needed to address such requirements, but the limitations of traditional MAC have inhibited its adoption into mainstream operating systems. The National Security Agency (NSA) worked with Secure Computing Corporation (SCC) to develop a flexible MAC architecture called Flask to overcome the limitations of traditional MAC. The NSA has implemented this architecture in the Linux operating system, producing a Security-Enhanced Linux (SELinux) prototype, to make the technology available to a wider community and to enable further research into secure operating systems. NAI Labs has developed an example security policy configuration to demonstrate the benefits of the architecture and to provide a foundation for others to use. This paper describes the security architecture, security mechanisms, application programming interface, security policy configuration, and performance of SELinux.