Setypes

Setypes, in the context of SELinux, refer to the security type component of a subject’s or object’s security context. They are the primary labels used by Type Enforcement to determine whether a given operation is permitted. In a typical context the fields user:role:type:level, the setype corresponds to the type portion and is sometimes historically called the setype. The type label is what the policy uses to match rules such as allow, deny, and transition.

Types are defined in policy modules and form the core mechanism for access control. Examples include httpd_t for the httpd process domain, and httpd_sys_content_t for files that httpd is allowed to access. A rule like “allow httpd_t httpd_sys_content_t:file read” allows the httpd domain to read files labeled with httpd_sys_content_t. Objects and processes are labeled consistently so that policy decisions can be made without relying on user identity or process origin alone.

Management and labeling tools are used to assign or modify setypes. Common commands include chcon -t <type> to change the label of a path, restorecon to reset labels based on policy, and semanage fcontext -a -t <type> to define persistent labeling rules. Policies and contexts can be examined with tools such as sesearch or sesetroubleshoot.

Relation to policy and security posture: setypes enable granular control and isolation by separating responsibilities across domains and object types. In multi-level security (MLS) environments, the type label works alongside sensitivity levels to constrain interactions.

Terminology: the term setype appears in some documentation and older tooling, but modern usage often simply uses type to denote the security label within a context.