When working on the Records Management module, we needed additional functionality around permissions, and therefore introduced the ExtendedPermissionService.
The ExtendedPermissionService is wired in, via Spring config, to extend Alfresco's core PermissionService, and adds support for:
- the RMPermissionModel, which defines the available permissions capabilities.
- the PermissionProcessorRegistry, which introduces pre- and post- processors.
- other minor method extensions (e.g. to setInheritParentPermissions)
This was added in RM 2.4 to support the requirements around the additional security classifications and markings.
The registry is simply two array lists, one for pre-processors and one for post-processors, which are iterated around before / after (respectively) the wrapped call PermissionService.hasPermission
Out of the box, a system with the RM module installed will have the following permissions processors defined:
- None.
- RecordsManagementPermissionPostProcessor
- If the node is an RM node (i.e. it has the RecordsManagementModel.ASPECT_FILE_PLAN_COMPONENT marker aspect) and the core permissions evaluates to DENIED, then this post processor allows read/writes if the appropriate read/file permissions are present.
(links only work in clones of Enterprise repos)
- SecurityMarksPermissionPreProcessor
- For all content: denies the result if the required security clearance rules (for classification or marks) are not satisfied. (uses securityClearanceService.isClearedFor)
- None.
Additional processors can be defined by extending either PermissionPreProcessorBaseImpl or PermissionPostProcessorBaseImpl which call the add method on the appropriate list during init.
There is certainly a performance overhead when adding additional processing to permission checks. This is most noticeable in the SecurityMarksPermissionPreProcessor where we need to call out to an external service. This has been profiled heavily and optimised during 2.5 and 2.6 development.
###TODO: Not yet documented (in related areas of the code) are:
- Capabilities (see rm-capabilities-*.xml, declarativeCapability.java and DeclarativeCompositeCapability.java)
- RM's permission system has an any allow allows policy unlike alfresco which policy is any deny denies