And how often will they be happy to type them cs 236

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Unformatted text preview: each role – E.g., Unix sudo, which only requires your basic password • How many passwords will people remember? – And how often will they be happy to type them? CS 236 Online Lecture 3 Page 26 Problems of Disjoint Roles • Each role should have disjoint privileges – More secure if roles aren’t supersets of other roles • May cause difficulties if certain operations require privileges from different roles CS 236 Online Lecture 3 Page 27 Problems of System Administration • Access control is only useful if the permissions are set correctly for each subject and object • The more subjects there are, the more work system administrators must do – Since each subject needs to get only the proper privileges CS 236 Online Lecture 3 Page 28 RBAC in Real Systems • Windows has provided an RBAC API since Windows Server 2003 – Authorization Manager • Most Linux systems have RBAC add-ons – SELinux includes RBAC – Some other Linux distributions do, too • Also lots of special tools to build RBAC systems under Windows CS 236 Online Lecture 3 Page 29 Reference Monitors • Whatever form it takes, access control must be instantiated in actual code – That checks if a given attempt to reference an object should be allowed • That code is called a reference monitor • Obviously, good reference monitors are critical for system security CS 236 Online Lecture 3 Page 30 Desirable Properties of Reference Monitors • • • • • Correctness Proper placement...
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This document was uploaded on 11/01/2013.

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