What type of security policy does SELinux primarily support?

SELinux primarily supports mandatory access controls (MAC), which is a security policy framework that restricts how subjects (such as users or processes) can access objects (like files or resources). In a MAC system, access rights are determined by a central authority (the system administrator) and are enforced throughout the system regardless of the user's wishes. This is in contrast to discretionary access controls (DAC), where users can control access to their own resources.

In the case of SELinux, policies are defined that set strict rules about what processes can access which files or resources, thus allowing for a more controlled and secure environment. This is particularly important in multi-user systems, where it can prevent unauthorized access and limit the potential damage from compromised applications.

While role-based access controls (RBAC) do exist and may be implemented alongside MAC, they focus on assigning roles to users with specific access permissions rather than enforcing strict policies as seen in MAC. Content-based access controls are not a primary focus of SELinux either. The emphasis on mandatory access controls is what distinguishes SELinux from other security implementations, making it a robust option for enhancing system security in Linux environments.