ITOSS: An Integrated Toolkit For Operating System

Public and private organizations maintain large systems of files to be accessed by many users. Clearly, access to information in these files must be regulated so that specific items are made available to specific users, in accordance with rules and limitations deemed appropriate by management. The totality of these rules and limitations constitute the (information) security policy of the organization. Nowadays such systems of files reside within computer systems, usually on secondary memory devices such as magnetic or optical disks or magnetic tapes. The files are accessed through computers, on terminals or printers, in a time-shared mode on a single computer, or in a distributed system of computers and file servers linked together. Computer systems are governed by operating systems which, among other tasks, implement and regulate the total user interaction with the system, including user access to the file system. Any hostile impingement on the integrity of the operating system poses grave dangers to the security of the file system, as well as to the proper intended behavior of the computer. Thus security requirements include the protection of operating systems from unauthorized incursion and subversion. We feel that a method or model for implementing secure operating systems should posses the following attributes: