## *hsadmin-ng*'s Role-Based-Access-Management (RBAC) The requirements of *hsadmin-ng* include table-m row- and column-level-security for read and write access to business-objects. More precisely, any access has to be controlled according to given rules depending on the accessing users, their roles and the accessed business-object. Further, roles and business-objects are hierarchical. To avoid misunderstandings, we are using the term "business-object" what's usually called a "domain-object". But as we are in the context of a webhosting infrastructure provider, "domain" would have a double meaning. Our implementation is based on Role-Based-Access-Management (RBAC) in conjunction with views and triggers on the business-objects. As far as possible, we are using the same terms as defined in the RBAC standard, for our function names though, we chose more expressive names. In RBAC, subjects can be assigned to roles, roles can be hierarchical and eventually have assigned permissions. A permission allows a specific operation (e.g. view or edit) on a specific (business-) object. You can find the entity structure as a UML class diagram as follows: ```plantuml @startuml ' left to right direction top to bottom direction ' hide the ugly E in a circle left to the entity name hide circle ' use right-angled line routing skinparam linetype ortho package RBAC { ' forward declarations entity RbacUser together { entity RbacRole entity RbacPermission RbacUser -[hidden]> RbacRole RbacRole -[hidden]> RbacUser } together { entity RbacGrant enum RbacReferenceType entity RbacReference } RbacReference -[hidden]> RbacReferenceType entity RbacGrant { ascendantUuid: uuid(RbackReference) descendantUuid: uuid(RbackReference) auto } RbacGrant o-u-> RbacReference RbacGrant o-u-> RbacReference enum RbacReferenceType { RbacUser RbacRole RbacPermission } RbacReferenceType ..> RbacUser RbacReferenceType ..> RbacRole RbacReferenceType ..> RbacPermission entity RbacReference { *uuid : uuid <> -- type : RbacReferenceType } RbacReference o--> RbacReferenceType entity RbacUser { *uuid : uuid <> -- name : varchar } RbacUser o-- RbacReference entity RbacRole { *uuid : uuid(RbacReference) -- name : varchar } RbacRole o-- RbacReference together { enum RbacOperation entity RbacObject } entity RbacPermission { *uuid : uuid(RbacReference) -- objectUuid: RbacObject op: RbacOperation } RbacPermission o-- RbacReference RbacPermission o-- RbacOperation RbacPermission *-- RbacObject enum RbacOperation { add-package add-domain add-unixuser ... view edit delete } entity RbacObject { *uuid : uuid <> -- objectTable: varchar } RbacObject o- "Business Objects" } package "Business Objects" { entity package package *--u- RbacObject entity customer customer *--u- RbacObject entity "..." as moreBusinessObjects moreBusinessObjects *-u- RbacObject } @enduml ``` ### The RBAC Entity Types #### RbacReference An *RbacReference* is a generalization of all entity types which participate in the hierarchical role system, defined via *RbacGrant*. The primary key of the *RbacReference* and its referred object is always identical. #### RbacReferenceType The enum *RbacReferenceType* describes the type of reference. It's only needed to make it easier to find the referred object in *RbacUser*, *RbacRole* or *RbacPermission*. #### RbacUser An *RbacUser* is a type of RBAC-subject which references a login account outside this system, identified by a name (usually an email-address). *RbacUser*s can be assigned to multiple *RbacRole*s, through which they can get permissions to *RbacObject*s. The primary key of the *RbacUser* is identical to its related *RbacReference*. #### RbacRole An *RbacRole* represents a collection of directly or indirectly assigned *RbacPermission*s. Each *RbacRole* can be assigned to *RbacUser*s or to another *RbacRole*. Both kinds of assignments are represented via *RbacGrant*. *RbacRole* entities can *RbacObject*s, or more precise #### RbacPermission An *RbacPermission* allows a specific *RbacOperation* on a specific *RbacObject*. #### RbacOperation An *RbacOperation* determines, what an *RbacPermission* allows to do. It can be one of: - **'add-...'** - permits creating new instances of specific entity types underneath the object specified by the permission, e.g. "add-package" - **'view'** - permits reading the contents of the object specified by the permission - **'edit'** - change the contents of the object specified by the permission - **'delete'** - delete the object specified by the permission - **'\*'** This list is extensible according to the needs of the access rule system. Please notice, that there is no **create** operation to create new instances of unrelated business-object-types. For such a singleton business-object-type, e.g. *Organization" or "Hostsharing" has to be defined, and its single entity is referred in the permission. Only with this rule, the foreign key in *RbacPermission* can be defined as `NOT NULL`. #### RbacGrant The *RbacGrant* entities represent the access-rights structure from *RbacUser*s via hierarchical *RbacRoles* down to *RbacPermission*s. The core SQL queries to determine access rights are all recursive queries on the *RbacGrant* table. ### Role naming The naming pattern of a role is important to be able to address specific roles. E.g. if a new package is added, the admin-role of the related customer has to be addressed. There can be global roles like 'administrators'. Most roles, though, are specific for certain business-objects and automatically generated as such: business-object-table#business-object-name.relative-role Where *business-object-table* is the name of the SQL table of the business object (e.g *customer* or 'package'), *business-object-name* is generated from an immutable business key(e.g. a prefix like 'xyz' or 'xyz00') and the *relative-role*' describes the role relative to the referenced business-object as follows: #### owner The owner-role is granted to the subject which created the business object. E.g. for a new *customer* it would be granted to 'administrators' and for a new *package* to the 'customer#...admin'. Whoever has the owner-role assigned can do everything with the related business-object, including deleting (or deactivating) it. In most cases, the permissions to other operations than 'delete' are granted through the 'admin' role. By this, all roles ob sub-objects, which are assigned to the 'admin' role, are also granted to the 'owner'. #### admin The admin-role is granted to a role of those subjects who manage the business object. E.g. a 'package' is manged by the admin of the customer. Whoever has the admin-role assigned, do everything with the related business-object, including deleting (or deactivating) it. In most cases, the permissions to the 'view' operation is granted through the 'tenant' role. By this, all roles ob sub-objects, which are assigned to the 'tenent' role, are also granted to the 'admin'. #### tenant The tenant-role is granted to everybody who needs to be able to view the business-object. Usually all owners, admins and tenants of sub-objects get this role granted. Some business-objects only have very limited data directly in the main business-object and store more sensitive data in special sub-objects (e.g. 'customer-details') to which tenants of sub-objects of the main-object (e.g. package admins) do not get view permission. ## Example Users, Roles, Permissions and Business-Objects The following diagram shows how users, roles and permissions could be granted access to operations on business objects. ```plantuml @startuml ' left to right direction top to bottom direction ' hide the ugly E in a circle left to the entity name hide circle ' use right-angled line routing ' skinparam linetype ortho package RbacUsers { object UserMike object UserSuse object UserPaul } package RbacRoles { object RoleAdministrators object RoleCustXyz_Owner object RoleCustXyz_Admin object RolePackXyz00_Owner } RbacUsers -[hidden]> RbacRoles package RbacPermissions { object PermCustXyz_View object PermCustXyz_Edit object PermCustXyz_Delete object PermCustXyz_AddPackage object PermPackXyz00_View object PermPackXyz00_Edit object PermPackXyz00_Delete object PermPackXyz00_AddUser } RbacRoles -[hidden]> RbacPermissions package BusinessObjects { object CustXyz object PackXyz00 } RbacPermissions -[hidden]> BusinessObjects UserMike o---> RoleAdministrators UserSuse o--> RoleCustXyz_Admin UserPaul o--> RolePackXyz00_Owner RoleAdministrators o..> RoleCustXyz_Owner RoleCustXyz_Owner o-> RoleCustXyz_Admin RoleCustXyz_Admin o-> RolePackXyz00_Owner RoleCustXyz_Owner o--> PermCustXyz_Edit RoleCustXyz_Owner o--> PermCustXyz_Delete RoleCustXyz_Admin o--> PermCustXyz_View RoleCustXyz_Admin o--> PermCustXyz_AddPackage RolePackXyz00_Owner o--> PermPackXyz00_View RolePackXyz00_Owner o--> PermPackXyz00_Edit RolePackXyz00_Owner o--> PermPackXyz00_Delete RolePackXyz00_Owner o--> PermPackXyz00_AddUser PermCustXyz_View o--> CustXyz PermCustXyz_Edit o--> CustXyz PermCustXyz_Delete o--> CustXyz PermCustXyz_AddPackage o--> CustXyz PermPackXyz00_View o--> PackXyz00 PermPackXyz00_Edit o--> PackXyz00 PermPackXyz00_Delete o--> PackXyz00 PermPackXyz00_AddUser o--> PackXyz00 @enduml ``` ## Business-Object-Tables, Triggers and Views To support the RBAC system, for each business-object-table, some more artifacts are created in the database: - a `BEFORE INSERT TRIGGER` which creates the related *RbacObject* instance, - an `AFTER INSERT TRIGGER` which creates the related *RbacRole*s, *RbacPermission*s together with their related *RbacReference*s as well as *RbacGrant*s, - a restricted view (e.g. *customer_rv*) through which restricted users can access the underlying data. Not yet implemented, but planned are these actions: - an `ON DELETE ... DO INSTEAD` rule to allow `SQL DELETE` if applicable for the business-object-table and the user has 'delete' permission, - an `ON UPDATE ... DO INSTEAD` rule to allow `SQL UPDATE` if the user has 'edit' right, - an `ON INSERT ... DO INSTEAD` rule to allow `SQL INSERT` if the user has 'add-..' right to the parent-business-object. The restricted view takes the current user from a session property and applies the hierarchy of its roles all the way down to the permissions related to the respective business-object-table. This way, each user can only view the data they have 'view'-permission for, only create those they have 'add-...'-permission, only update those they have 'edit'- and only delete those they have 'delete'-permission to. ### Current User The current use is taken from the session variable `hsadminng.currentUser` which contains the name of the user as stored in the *RbacUser*s table. Example: SET LOCAL hsadminng.currentUser = 'mike@hostsharing.net'; That user is also used for historicization and audit log, but which is a different topic. ### Assuming Roles If the session variable `hsadminng.assumedRoles` is set to a non-empty value, its content is interpreted as a list of semicolon-separated role names. Example: SET LOCAL hsadminng.assumedRoles = 'customer#aab.admin;customer#aac.admin'; In this case, not the current user but the assumed roles are used as a starting point for any further queries. Roles which are not granted to the current user, directly or indirectly, cannot be assumed. ### Example A full example is shown here: BEGIN TRANSACTION; SET SESSION SESSION AUTHORIZATION restricted; SET LOCAL hsadminng.currentUser = 'mike@hostsharing.net'; SET LOCAL hsadminng.assumedRoles = 'customer#aab.admin;customer#aac.admin'; SELECT c.prefix, p.name as "package", ema.localPart || '@' || dom.name as "email-address" FROM emailaddress_rv ema JOIN domain_rv dom ON dom.uuid = ema.domainuuid JOIN unixuser_rv uu ON uu.uuid = dom.unixuseruuid JOIN package_rv p ON p.uuid = uu.packageuuid JOIN customer_rv c ON c.uuid = p.customeruuid; END TRANSACTION; ## Roles and Their Assignments for Certain Business Objects To give you an overview of the business-object-types for the following role-examples, check this diagram: ```plantuml @startuml left to right direction ' top to bottom direction ' hide the ugly E in a circle left to the entity name hide circle ' use right-angled line routing ' skinparam linetype ortho entity EMailAddress entity Domain Domain o-- "*" EMailAddress entity UnixUser UnixUser o-- "*" Domain entity Package Package o.. "*" UnixUser entity Customer Customer o-- "*" Package @enduml ``` It's mostly an example hierarchy of business-object-types, but resembles a part of Hostsharing's actual hosting infrastructure. The following diagrams show which roles are created for each business-object-type and how they relate to roles from other business-object-types. ### Customer Roles The highest level of the business-object-type-hierarchy is the *Customer*. ```plantuml @startuml ' left to right direction top to bottom direction ' hide the ugly E in a circle left to the entity name hide circle ' use right-angled line routing ' skinparam linetype ortho entity "BObj customer#xyz" as boCustXyz together { entity "Perm customer#xyz *" as permCustomerXyzAll permCustomerXyzAll --> boCustXyz entity "Perm customer#xyz add-package" as permCustomerXyzAddPack permCustomerXyzAddPack --> boCustXyz entity "Perm customer#xyz view" as permCustomerXyzView permCustomerXyzView --> boCustXyz } entity "Role customer#xyz.tenant" as roleCustXyzTenant roleCustXyzTenant --> permCustomerXyzView entity "Role customer#xyz.admin" as roleCustXyzAdmin roleCustXyzAdmin --> roleCustXyzTenant roleCustXyzAdmin --> permCustomerXyzAddPack entity "Role customer#xyz.owner" as roleCustXyzOwner roleCustXyzOwner ..> roleCustXyzAdmin roleCustXyzOwner --> permCustomerXyzAll entity "Role administrators" as roleAdmins roleAdmins --> roleCustXyzOwner @enduml ``` As you can see, there something special: From the 'Role customer#xyz.owner' to the 'Role customer#xyz.admin' there is a dashed line, whereas all other lines are solid lines. Solid lines means, that one role is granted to another and followed in all queries to the restricted views. The dashed line means that one role is granted to another but not automatically followed in queries to the restricted views. The reason here is that otherwise simply too many objects would be accessible to those with the 'administrators' role and all queries would be slowed down vastly. Grants which are not followed are still valid grants for `hsadminng.assumedRoles`. Thus, if you want to access anything below a customer, assume its role first. There is actually another speciality in the customer roles: For all others, a user defined by the customer gets the owner role assigned, just for the customer, the owners role is assigned to the 'administrators'. ### Package Roles One example of the business-object-type-level right below is the *Package*. ```plantuml @startuml ' left to right direction top to bottom direction ' hide the ugly E in a circle left to the entity name hide circle ' use right-angled line routing ' skinparam linetype ortho entity "BObj pacage#xyz00" as boPacXyz00 together { entity "Perm pacage#xyz00 *" as permPackageXyzAll permPackageXyzAll --> boPacXyz00 entity "Perm pacage#xyz00 add-unixuser" as permPacXyz00AddUser permPacXyz00AddUser --> boPacXyz00 entity "Perm pacage#xyz00 edit" as permPacXyz00Edit permPacXyz00Edit --> boPacXyz00 entity "Perm pacage#xyz00 view" as permPacXyz00View permPacXyz00View --> boPacXyz00 } package { entity "Role customer#xyz.tenant" as roleCustXyzTenant entity "Role customer#xyz.admin" as roleCustXyzAdmin entity "Role customer#xyz.owner" as roleCustXyzOwner } package { entity "Role pacage#xyz00.owner" as rolePacXyz00Owner entity "Role pacage#xyz00.admin" as rolePacXyz00Admin entity "Role pacage#xyz00.tenant" as rolePacXyz00Tenant } rolePacXyz00Tenant --> permPacXyz00View rolePacXyz00Tenant --> roleCustXyzTenant rolePacXyz00Owner --> rolePacXyz00Admin rolePacXyz00Owner --> permPackageXyzAll roleCustXyzAdmin --> rolePacXyz00Owner roleCustXyzAdmin --> roleCustXyzTenant roleCustXyzOwner ..> roleCustXyzAdmin rolePacXyz00Admin --> rolePacXyz00Tenant rolePacXyz00Admin --> permPacXyz00AddUser rolePacXyz00Admin --> permPacXyz00Edit entity "Role administrators" as roleAdmins roleAdmins --> roleCustXyzOwner @enduml ``` Initially, the customer's admin role gets the package owner role granted. They can use the package's admin role to hand over most management functionality to a third party. The 'administrators' can get access through an assumed customer's admin role or directly by assuming the package's owner or admin role.