Fine grained object protection in UNIX

In this document we describe and discuss a solution, called UNIX Access Table Protection (UATP), to the problem of providing a secure environment for persistent object types with fine grained protection on a UNIX system. UATP requires no modifications to the UNIX kernel. Users on UNIX have discretionary access control over their directories and files. By using these controls in a particular way, this paper shows a way in which a hierarchy of protection domains can be set up to enable object methods and type instances to be managed securley and to be protected from unauthorised use. The document also describes how a particular object type, UATP - kernel, which executes in these protection domains (in the same way as all other objects) can be used to provide fine grained protection for all other objects which are installed and running in the manner described here.