rolesfrom

Rolesfrom is a concept used in access control policy design to describe a mechanism that derives the set of roles assigned to a subject from one or more sources of truth. It is employed within attribute-based and policy-based frameworks to compute the effective roles that influence authorization decisions. Unlike static role assignments, rolesfrom enables dynamic derivation of roles from external identity providers, directory services, or internal attribute stores.

The exact syntax and semantics of rolesfrom vary by system and policy language, but it generally takes a subject context and a source identifier as input and returns a set of role identifiers. In practice, a policy might invoke rolesfrom to determine whether a user belongs to a given role based on their group memberships, attributes, or other provenance data. For example, a pseudo-policy could use rolesfrom(user, 'ldapGroups') to infer the roles assigned via directory groups.

Common sources for rolesfrom include LDAP or Active Directory groups, SAML or OpenID Connect attributes, application databases, and custom attribute stores. Rolesderived can then drive fine-grained permissions, dynamic feature access, or delegated administration in multi-tenant or federated environments.

Security and design considerations are important with rolesfrom. Systems should validate the provenance and integrity of the role data, address potential staleness or revocation, and ensure that role mappings do not introduce privilege escalation. Performance implications, caching strategies, and clear mappings between source roles and authorization actions are also critical.

See also: role-based access control, attribute-based access control, policy languages such as XACML, and policy engines like Open Policy Agent.