A yuuvis® Momentum user has to be authorized to the functionality of the system by assigning roles. For the individual roles, permissions can be set to allow actions on objects restricted by defined conditions where appropriate and the usage of specific endpoints can be controlled.

Introduction

The Core API protects documents against access by unauthorized persons through a permission system. Each user has one or more roles in this system, giving them access to various documents for specified actions. The user-role mapping manages the assignment of roles to users. In yuuvis® Momentum, this mapping is managed separately from the authentication process itself and can be configured according to the customers' needs. Furthermore, in the configuration of the yuuvis® AUTHENTICATION service, access conditions can be defined individually for each API endpoint.

Structure of the Permissions System

Roles and Role Sets

The permissions to access documents or to perform certain actions are assigned to specific roles. Users of the system are assigned to particular roles, and through those role assignments acquire the permissions needed—they become the owner of the roles. In general, roles are reusable groups of various permissions. Each role has a unique name and contains one or more permissions that are granted to its owners.

Note: In the header of each incoming and authenticated API call, the roles of the corresponding user are included among other user-specific information. If you assign too many roles with long names to individual users, you might exceed the overall size limit of 8 KB for the header.

Permissions

Permissions denote access rights to certain objects and are assigned to a role. A permission consists of one or more actions and, optionally, a condition. The condition defines which objects are allowed to be managed by owners of a role with the permission, whereas actions define what procedures are allowed upon meeting the condition. In other words, if a user tries to access an object, the authorization system will go through that user's roles to see if one of the conditions within their permissions is met by the object. If the object meets the condition of one of the user's permissions, the user will be able to work with the object according to the actions defined by that permission.

Actions

The actions of a permission specify access rights for specific purposes, whereby a distinction is currently made between create access, read access, delete access and write access. The actions can be combined by simply adding multiple actions to the permission.

`create` (as of 2021 Autumn)	permission to create new objects
`read`	permission to know about the existence of objects, to receive them in search results and to call various GET endpoints to a special object
`delete`	permission that allows to delete content or metadata of objects for which also `read` permission is granted
`write`	permission to update objects or to move the content of objects for which also `read` permission is granted

Conditions

Conditions are statements in the proprietary CMIS-based query language that define the subset of documents in the system affected by a permission. If the condition for a document is met (meaning evaluating the query language expression returns 'true'), the owner of the role gets to access that document. For example, conditions can limit a user's access to a specific type of object or hide documents that are older than a specific date. The conditions are applied to all requests from the role owner and thereby act as filters for the corresponding search results.

Note: In a permission the CONTAINS()query function cannot be used in a condition. The whole statement would always be evaluated as false, even if the condition contains other sub-statements that do not use CONTAINS() and that would individually considered be evaluated as true.

The condition can also be left out – indicating that the permission applies to all documents in the system.

The following code block explains the definition of permissions with an example of creation permissions assigned to different roles.

Examples for Creation Permissions with Condition and without

<!-- Users with this role are not allowed to create, update or delete any object. -->
<role>
   <name>CAN_CREATE_NOTHING</name>
</role>

<!-- Users with this role can create any object. No conditions have to be matched. -->
<role>
   <name>CAN_CREATE_EVERYTHING</name>
   <permission>
       <action>create</action>
   </permission>
</role>

<!-- Users with this role can create objects that match the condition. In this case only objects of type 'appTable:order' or 'appEmail:email' can be created. -->
<role>
   <name>CAN_CREATE_SOMETHING</name>
   <permission>
      <action>create</action>
      <condition>
         system:objectTypeId IN ('appTable:order', 'appEmail:email')
   	  </condition>
   </permission>
</role>

Endpoints for Managing Permissions

The following endpoints are available for setting up and managing your tenant-specific permissions system:

Retrieve the tenant role set - GET /api/admin/permissions
Update the tenant role set - POST /api/admin/permissions
Validate the tenant role set - POST /api/admin/permissions/validate

For system administrators, the following endpoints are available for managing the global permissions system:

Retrieve the global role set - GET /api/system/permissions
Update the global role set - POST /api/system/permissions
Validate the global role set - POST /api/system/permissions/validate

Since version 2.4, yuuvis® Momentum has the ability to further structure the global role set into applications. This goes hand in hand with the usage of application schemata, as the new functionality is meant to exclude any role set entries related to an optional application schema from the main global role set.

Retrieve a global application role set - GET /api/system/apps/{app}/permissions
Update a global application role set - POST /api/system/apps/{app}/permissions
Validate a global application role set - POST /api/system/apps/{app}/permissions/validate

To streamline the process of defining yuuvis® Momentum role sets, a number of REST endpoints were made available to retrieve the current role set structures and to apply modifications. As seen in the permissions concept page, there are three options used to structure the role set, coming from two endpoint categories. The /system/permissions and /system/apps/{app}/permissions endpoints are both used to modify the global role set applicable to all users of the system, whereas the /admin/permissions endpoint serves to change the role set specific to the current tenant.

Complete role set files can be supplied to one of the endpoints via an HTTP POST request, overwriting the previous role set present at that position. Thus, retrieving and extending the previous role set state using a GET request on the same endpoint is strongly recommended. New role sets can also be validated by posting them to the role set endpoint URLs using the added URL suffix /validate.

>> Code examples in gitHub

Role Administration

Defining Roles

The roles are defined in role sets. Each role set is stored via the CONFIG service in a file roleset.xml that should only be changed using the above listed endpoints.

A role has a name and a list of permissions. Each permission can have one or more actions: read, delete and write. Additionally, they can be restricted by a condition.

Example: a read-permission with the condition system:objectTypeId = 'email' allows to receive all objects of type 'email' in search results and to call various GET endpoints for this type of objects.

An example role set

<?xml version="1.0" encoding="utf-8"?>
<roleSet xmlns="http://optimal-systems.org/ns/dmscloud/roleset/"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://optimal-systems.org/ns/dmscloud/roleset/ dmsCloud-roles.xsd">
    <role>
        <name>RoleEmail</name>
        <permission>
            <action>read</action>
            <condition>system:objectTypeId = 'email:email'</condition>
        </permission>
    </role>
    <role>
        <name>RoleDocument</name>
        <permission>
            <action>read</action>
            <condition>system:objectTypeId = 'document'</condition>
        </permission>
    </role>
    <role>
        <name>RoleEmailAndDocument</name>
        <permission>
            <action>read</action>
            <condition>system:objectTypeId in ('email:email', 'document')</condition>
        </permission>
    </role>
    <role>
        <name>AdminRole</name>
        <permission>
            <action>read</action>
            <action>delete</action>
        </permission>
    </role>
</roleSet>

>> The XSD for role sets: dmsCloud-roleSet.xsd.

Note: For the usage of some Additional Services a fixed role set is required.
>> Defining Roles for a Library-based Client

User-Role Mapping

When users log in at the beginning of a session and are successfully authenticated by the identity provider, a JSON web token is generated in which the users' roles are listed under authorities. The GET user.info webhook is responsible for providing the users' roles. By customizing the webhook, it is possible to connect any access management provider delivering the users' roles in a suitable format. Per default, the webhook calls the ORGANIZATION service that is responsible for providing the role information.

To assign individual roles to the users of the system, an external identity provider is used, which takes over the responsibility for role assignment. Per default, the ORGANIZATION service reads the keycloak profile and thus requests the information from the identity provider Keycloak.

In order to run the ORGANIZATION service in Keycloak mode, the keycloak profile has to be activated and the following connection parameters in the application-oauth2.yml profile are required:

keycloak.server
keycloak.admin.username
keycloak.admin.password

Note

The roles of users control their rights regarding DMS objects but also regarding yuuvis® Momentum administration. In the default configuration, e.g., the YUUVIS_SYSTEM_INTEGRATOR role allows editing of global configuration files like role sets and schemata. Thus, it is highly important to configure your role management software such that only system operators can assign roles that provide themselves and other users with global rights.

Access Authorization for Endpoints

The AUTHENTICATION service decides for each API request of any user if the access is granted or not. In its configuration, the access conditions can be defined individually for each API endpoint. Thus, permissions in yuuvis® Momentum can be set not only for types of actions and the usage of specific object types, but also directly for API endpoints. It is even possible to allow the usage of an API endpoint for callers without authentication.

>> AUTHENTICATION Service

Summary

This article explained the role-based structure of the permission system provided by the Core API. The global and the tenant-specific role set can be changed via the corresponding endpoints. The user-role mapping can be managed in Keycloak. The access authentication for individual yuuvis® API endpoints can be configured via the AUTHENTICATION service.

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