6 RBAC Policies Given a program with sets of methods M, roles R, and users U, role formulae B(R) are propositional logic statements over R, where each r  R is considered as a predicate An RBAC policy is a tuple P = (R, U, υ, μ, π), where: –υ : U → B(R) is the user role assignment function (conjunction of roles) –μ : M → B(R) is the role requirement function (disjunction of roles) –π : M z B(R) is the principal delegation partial function Roles Granted: Student, Assistant Role Required: Student or Assistant run-as: Professor Role Required: Professor Component Intercomponent call Intracomponent call m0 m1 m2 m3 m4 m5 m6 m7 Role Required: Student User: bob υ( bob ) = Student  Assistant μ( m1 ) = Student  Assistant π( m1 ) = π( m4 ) = Professor μ( m6 ) = Student μ( m7 ) = Student μ( m5 ) = Professor μ( m0 ) = Student μ( m3 ) = Professor
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