Role-based access control is a common pattern in security, providing extensible role-specific behavior while retaining straightforward management. This module creates a standard API to assign and query roles on Fedora objects.

Objects do not have permissions specified in their properties;  rather, objects have roles assigned, and then permissions are mapped onto roles elsewhere.  This makes it much easier to manage permissions globally:  rarely will masses of objects need to be updated if their permissions change.  Only the role-to-permission mapping will be updated.

The module does not define the set of roles that may be assigned. If you choose to configure a set of supported roles, then the roles assigned via this API will be validated.

Order of operation:

• Container Authentication: A user comes into the system.  They are assigned one or more principals:
  
  • If they authenticate through some authentication gateway, then their principal may be generated from some of the person's attributes;
  • Whether they authenticate or not, the request will be assigned a default "everyone" principal
• Fedora Principal Factory Extensions: Principal factory extensions may bring in more principals after authentication, such as groups, from sources like LDAP.
• Fedora Roles PEP Queries for Assigned Roles on Content: What roles have been assigned?
  
  • The authorization layer queries the requested repository object(s) for all roles that are assigned to principals.
  • If none are found locally, then it will query each ancestor in turn until role assignments are found.
  • If no role assignments are found in the tree of objects, then a default set of role assignments is used.
• Fedora Roles PEP - Role Resolution: What roles does this request have?
  
  • Assigned roles are compared with the set of principals for the request. Any roles assigned to principals for the request are considered effective.
  • At this point we have the effective access roles for this operation
• Fedora Roles PEP - Policy Enforcement: Can this role perform the requested operation?
  
  • The Fedora PEP is an extension point, so enforcement will vary by the chosen implementation. We assume that installations will combine the access roles module with a roles-based PEP.
  • Effective roles will be used to determine if the user is permitted to perform the action on a given object.
• The PEP will return a response to ModeShape, which will throw an exception to Fedora if access has been denied.
• Fedora will respond with a 403 if the given REST operation is denied.
  
  
• The one exception to this process is the fedoraAdmin container role.  if the request has a fedoraAdmin user role (in the container), then no object checks are made. The PEP is not consulted as admins have permission to do everything. Objects will never have the fedoraAdmin role explicitly assigned to them, since it is a container role and not a content role. (e.g. a tomcat user role)

This module assigns roles to generic security principals, i.e. any class that implements java.security.Principal. Roles are serialized and matched against the principal name, a string property of the principal. All the principals used in your repository environment must have unique names. Other than that, you may use whatever principals you wish. This module does not validate principal names.