How does SELinux work?
Though it uses multiple security models to do its job, the type enforcement model is most important to SELinux. A type is a way of classifying an application or resource. Type enforcement is the enforcement of access control on that type. All files, processes, network resources, etc on an SELinux system has a label, and one of the components of that label is the “type”. For example the files in your home directory are probably labeled user_home_t. user_home_t is the type and in this case it means that the policy should treat all those files as your home directory files. Running applications also have labels. For example, your web browser may be running as firefox_t. Type enforcement simply allows you to specify what application label can access what resource label.
