Scoping tokens | Authentication and authorization

About scoping tokens
- User scopes
- Role scope
Adding unauthenticated groups to cluster roles

About scoping tokens

You can create scoped tokens to delegate some of your permissions to another user or service account. For example, a project administrator might want to delegate the power to create pods.

A scoped token is a token that identifies as a given user but is limited to certain actions by its scope. Only a user with the cluster-admin role can create scoped tokens.

Scopes are evaluated by converting the set of scopes for a token into a set of PolicyRules. Then, the request is matched against those rules. The request attributes must match at least one of the scope rules to be passed to the "normal" authorizer for further authorization checks.

User scopes

User scopes are focused on getting information about a given user. They are intent-based, so the rules are automatically created for you:

user:full - Allows full read/write access to the API with all of the user’s permissions.
user:info - Allows read-only access to information about the user, such as name and groups.
user:check-access - Allows access to self-localsubjectaccessreviews and self-subjectaccessreviews. These are the variables where you pass an empty user and groups in your request object.
user:list-projects - Allows read-only access to list the projects the user has access to.

Role scope

The role scope allows you to have the same level of access as a given role filtered by namespace.

role:<cluster-role name>:<namespace or * for all> - Limits the scope to the rules specified by the cluster-role, but only in the specified namespace .

Caveat: This prevents escalating access. Even if the role allows access to resources like secrets, rolebindings, and roles, this scope will deny access to those resources. This helps prevent unexpected escalations. Many people do not think of a role like edit as being an escalating role, but with access to a secret it is.

role:<cluster-role name>:<namespace or * for all>:! - This is similar to the example above, except that including the bang causes this scope to allow escalating access.

Adding unauthenticated groups to cluster roles

As a cluster administrator, you can add unauthenticated users to the following cluster roles in OKD by creating a cluster role binding. Unauthenticated users do not have access to non-public cluster roles. This should only be done in specific use cases when necessary.

You can add unauthenticated users to the following cluster roles:

system:scope-impersonation
system:webhook
system:oauth-token-deleter
self-access-reviewer

Always verify compliance with your organization’s security standards when modifying unauthenticated access.

Prerequisites

You have access to the cluster as a user with the cluster-admin role.
You have installed the OpenShift CLI (oc).

Procedure

Create a YAML file named add-<cluster_role>-unauth.yaml and add the following content:

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
 annotations:
   rbac.authorization.kubernetes.io/autoupdate: "true"
 name: <cluster_role>access-unauthenticated
roleRef:
 apiGroup: rbac.authorization.k8s.io
 kind: ClusterRole
 name: <cluster_role>
subjects:
 - apiGroup: rbac.authorization.k8s.io
   kind: Group
   name: system:unauthenticated

Apply the configuration by running the following command:
```
$ oc apply -f add-<cluster_role>.yaml
```