Nice introduction to SELinux and other option to enhance Linux security. Mandatory access control and role-based access control are relatively new to the Linux kernel. With the introduction of the LSM framework, new security modules will certainly become available. In addition to enhancements to the framework, it's possible to stack security modules, allowing multiple security modules to coexist and provide maximum coverage for Linux's security needs. New access-control methods will also be introduced as research into operating system security continues. From the article:
Linux has been described as one of the most secure operating systems available, but the National Security Agency (NSA) has taken Linux to the next level with the introduction of Security-Enhanced Linux (SELinux). SELinux takes the existing GNU/Linux operating system and extends it with kernel and user-space modifications to make it bullet-proof. If you're running a 2.6 kernel today, you might be surprised to know that you're using SELinux right now! This article explores the ideas behind SELinux and how it's implemented.