On-line error detection in the access of shared resources

The problem of protecting resources shared among several users is particularly demanding in systems that require information secrecy (bank and military applications) and in systems where the presence of unsafe or untested processes are likely to damage information residing in the system (SW development environments). A salution to this problem is to separate the intities residing in the system into subjects and objects, and to define a protection system which checks the accesses of subjects to objects and the interactions among subjects. In this paper the system entities control is extended to the operating system and the ability of such an extended protection system to detect misbehaviours caused by HW faults is considered. In this way an enhancement of on-line detection of HW faults, generating program anomalous behaviour is obtained.