Domain Transitions Using Entrypoints and Enters

Domain transitions allow the type of a process to be changed on execution, providing the primary mechanism for privilege change. Domain transitions are expressed via a source domain, a target domain, and a resource called an entrypoint. This allows the policy author to state that when the source domain executes an entrypoint the domain should be transitioned to the target domain.

The figure shows the graphical representation of the Entrypoint, passwd_exec.

The figure below represents the complete graphical depiction of a domain transition user (source) domain to the passwd (target) domain through the passwd_exec entrypoint. The arrow originating from the source domain and ending at the target domain through the entrypoint is called an Enter arrow in the CDS Framework Toolkit terminology and represents the domain transition as well as the direction of information flow from the source domain to the target domain.

In the CDS Framework Toolkit, the same entrypoint resource can be instantiated multiple times. Although the entrypoint resource may appear multiple times, each instance can have only one source and one destination. The combination of a source and an entrypoint represent a unique information flow, and it is not possible to connect a source domain to more than one instantiation of the same entrypoint resource.