RBAC Configuration

The RBAC feature enables restrictions of access to Argo CD resources. Argo CD does not have its own user management system and has only one built-in user, admin. The admin user is a superuser and it has unrestricted access to the system. RBAC requires SSO configuration or one or more local users setup. Once SSO or local users are configured, additional RBAC roles can be defined, and SSO groups or local users can then be mapped to roles.

There are two main components where RBAC configuration can be defined:

• The global RBAC config map (see argo-rbac-cm.yaml)
• The AppProject’s roles

Basic Built-in Roles

Argo CD has two pre-defined roles but RBAC configuration allows defining roles and groups (see below).

• role:readonly: read-only access to all resources
• role:admin: unrestricted access to all resources

These default built-in role definitions can be seen in builtin-policy.csv

Default Policy for Authenticated Users

When a user is authenticated in Argo CD, it will be granted the role specified in policy.default.

Restricting Default Permissions

All authenticated users get at least the permissions granted by the default policies. This access cannot be blocked by a deny rule. It is recommended to create a new role:authenticated with the minimum set of permissions possible, then grant permissions to individual roles as needed.

Anonymous Access

Enabling anonymous access to the Argo CD instance allows users to assume the default role permissions specified by policy.default without being authenticated.

The anonymous access to Argo CD can be enabled using the users.anonymous.enabled field in argocd-cm (see argocd-cm.yaml).

Warning

When enabling anonymous access, consider creating a new default role and assigning it to the default policies with policy.default: role:unauthenticated.

RBAC Model Structure

The model syntax is based on Casbin. There are two different types of syntax: one for assigning policies, and another one for assigning users to internal roles.

Group: Allows to assign authenticated users/groups to internal roles.

Syntax: g, <user/group>, <role>

• <user/group>: The entity to whom the role will be assigned. It can be a local user or a user authenticated with SSO. When SSO is used, the user will be based on the sub claims, while the group is one of the values returned by the scopes configuration.
• <role>: The internal role to which the entity will be assigned.

Policy: Allows to assign permissions to an entity.

Syntax: p, <role/user/group>, <resource>, <action>, <object>, <effect>

• <role/user/group>: The entity to whom the policy will be assigned
• <resource>: The type of resource on which the action is performed.
• <action>: The operation that is being performed on the resource.
• <object>: The object identifier representing the resource on which the action is performed. Depending on the resource, the object’s format will vary.
• <effect>: Whether this policy should grant or restrict the operation on the target object. One of allow or deny.

Below is a table that summarizes all possible resources and which actions are valid for each of them.

Application-Specific Policy

Some policy only have meaning within an application. It is the case with the following resources:

• applications
• applicationsets
• logs
• exec

While they can be set in the global configuration, they can also be configured in AppProject’s roles. The expected <object> value in the policy structure is replaced by <app-project>/<app-name>.

For instance, these policies would grant example-user access to get any applications, but only be able to see logs in my-app application part of the example-project project.

p, example-user, applications, get, *, allow
p, example-user, logs, get, example-project/my-app, allow

Application in Any Namespaces

When application in any namespace is enabled, the expected <object> value in the policy structure is replaced by <app-project>/<app-ns>/<app-name>. Since multiple applications could have the same name in the same project, the policy below makes sure to restrict access only to app-namespace.

p, example-user, applications, get, */app-namespace/*, allow
p, example-user, logs, get, example-project/app-namespace/my-app, allow

The applications resource

The applications resource is an Application-Specific Policy.

Fine-grained Permissions for update/delete action

The update and delete actions, when granted on an application, will allow the user to perform the operation on the application itself and all of its resources. It can be desirable to only allow update or delete on specific resources within an application.

To do so, when the action if performed on an application’s resource, the <action> will have the <action>/<group>/<kind>/<ns>/<name> format.

For instance, to grant access to example-user to only delete Pods in the prod-app Application, the policy could be:

p, example-user, applications, delete/*/Pod/*/*, default/prod-app, allow

Understand glob pattern behavior

Argo CD RBAC does not use / as a separator when evaluating glob patterns. So the pattern delete/*/kind/* will match delete/<group>/kind/<namespace>/<name> but also delete/<group>/<kind>/kind/<name>.

The fact that both of these match will generally not be a problem, because resource kinds generally contain capital letters, and namespaces cannot contain capital letters. However, it is possible for a resource kind to be lowercase. So it is better to just always include all the parts of the resource in the pattern (in other words, always use four slashes).

If we want to grant access to the user to update all resources of an application, but not the application itself:

p, example-user, applications, update/*, default/prod-app, allow

If we want to explicitly deny delete of the application, but allow the user to delete Pods:

p, example-user, applications, delete, default/prod-app, deny
p, example-user, applications, delete/*/Pod/*/*, default/prod-app, allow

Note

It is not possible to deny fine-grained permissions for a sub-resource if the action was explicitly allowed on the application. For instance, the following policies will allow a user to delete the Pod and any other resources in the application:

p, example-user, applications, delete, default/prod-app, allow
p, example-user, applications, delete/*/Pod/*/*, default/prod-app, deny

The action action

The action action corresponds to either built-in resource customizations defined in the Argo CD repository, or to custom resource actions defined by you.

The <action> has the action/<group>/<kind>/<action-name> format.

For example, a resource customization path resource_customizations/extensions/DaemonSet/actions/restart/action.lua corresponds to the action path action/extensions/DaemonSet/restart. If the resource is not under a group (for example, Pods or ConfigMaps), then the path will be action//Pod/action-name.

The following policies allows the user to perform any action on the DaemonSet resources, as well as the maintenance-off action on a Pod:

p, example-user, applications, action//Pod/maintenance-off, default/*, allow
p, example-user, applications, action/extensions/DaemonSet/*, default/*, allow

To allow the user to perform any actions:

p, example-user, applications, action/*, default/*, allow

The override action

When granted along with the sync action, the override action will allow a user to synchronize local manifests to the Application. These manifests will be used instead of the configured source, until the next sync is performed.

The applicationsets resource

The applicationsets resource is an Application-Specific policy.

ApplicationSets provide a declarative way to automatically create/update/delete Applications.

Allowing the create action on the resource effectively grants the ability to create Applications. While it doesn’t allow the user to create Applications directly, they can create Applications via an ApplicationSet.

Note

In v2.5, it is not possible to create an ApplicationSet with a templated Project field (e.g. project: {{path.basename}}) via the API (or, by extension, the CLI). Disallowing templated projects makes project restrictions via RBAC safe:

With the resource being application-specific, the <object> of the applicationsets policy will have the format <app-project>/<app-name>. However, since an ApplicationSet does belong to any project, the <app-project> value represents the projects in which the ApplicationSet will be able to create Applications.

With the following policy, a dev-group user will be unable to create an ApplicationSet capable of creating Applications outside the dev-project project.

p, dev-group, applicationsets, *, dev-project/*, allow

The logs resource

The logs resource is an Application-Specific Policy.

When granted with the get action, this policy allows a user to see Pod’s logs of an application via the Argo CD UI. The functionality is similar to kubectl logs.

The exec resource

The exec resource is an Application-Specific Policy.

When granted with the create action, this policy allows a user to exec into Pods of an application via the Argo CD UI. The functionality is similar to kubectl exec.

See Web-based Terminal for more info.

The extensions resource

With the extensions resource, it is possible to configure permissions to invoke proxy extensions. The extensions RBAC validation works in conjunction with the applications resource. A user needs to have read permission on the application where the request is originated from.

Consider the example below, it will allow the example-user to invoke the httpbin extensions in all applications under the default project.

p, example-user, applications, get, default/*, allow
p, example-user, extensions, invoke, httpbin, allow

The deny effect

When deny is used as an effect in a policy, it will be effective if the policy matches. Even if more specific policies with the allow effect match as well, the deny will have priority.

The order in which the policies appears in the policy file configuration has no impact, and the result is deterministic.

Policies Evaluation and Matching

The evaluation of access is done in two parts: validating against the default policy configuration, then validating against the policies for the current user.

If an action is allowed or denied by the default policies, then this effect will be effective without further evaluation. When the effect is undefined, the evaluation will continue with subject-specific policies.

The access will be evaluated for the user, then for each configured group that the user is part of.

The matching engine, configured in policy.matchMode, can use two different match modes to compare the values of tokens:

• glob: based on the glob package.
• regex: based on the regexp package.

When all tokens match during the evaluation, the effect will be returned. The evaluation will continue until all matching policies are evaluated, or until a policy with the deny effect matches. After all policies are evaluated, if there was at least one allow effect and no deny, access will be granted.

Glob matching

When glob is used, the policy tokens are treated as single terms, without separators.

Consider the following policy:

p, example-user, applications, action/extensions/*, default/*, allow

When the example-user executes the extensions/DaemonSet/test action, the following glob matches will happen:

1. The current user example-user matches the token example-user.
2. The value applications matches the token applications.
3. The value action/extensions/DaemonSet/test matches action/extensions/*. Note that / is not treated as a separator and the use of ** is not necessary.
4. The value default/my-app matches default/*.

Using SSO Users/Groups

The scopes field controls which OIDC scopes to examine during RBAC enforcement (in addition to sub scope). If omitted, it defaults to '[groups]'. The scope value can be a string, or a list of strings.

For more information on scopes please review the User Management Documentation.

The following example shows targeting email as well as groups from your OIDC provider.

apiVersion: v1
kind: ConfigMap
metadata:
  name: argocd-rbac-cm
  namespace: argocd
  labels:
    app.kubernetes.io/name: argocd-rbac-cm
    app.kubernetes.io/part-of: argocd
data:
  policy.csv: |
    p, my-org:team-alpha, applications, sync, my-project/*, allow
    g, my-org:team-beta, role:admin
    g, user@example.org, role:admin
  policy.default: role:readonly
  scopes: '[groups, email]'

This can be useful to associate users’ emails and groups directly in AppProject.

apiVersion: argoproj.io/v1alpha1
kind: AppProject
metadata:
  name: team-beta-project
  namespace: argocd
spec:
  roles:
    - name: admin
      description: Admin privileges to team-beta
      policies:
        - p, proj:team-beta-project:admin, applications, *, *, allow
      groups:
        - user@example.org # Value from the email scope
        - my-org:team-beta # Value from the groups scope

Local Users/Accounts

Local users are assigned access by either grouping them with a role or by assigning policies directly to them.

The example below shows how to assign a policy directly to a local user.

p, my-local-user, applications, sync, my-project/*, allow

This example shows how to assign a role to a local user.

g, my-local-user, role:admin

Ambiguous Group Assignments

If you have enabled SSO, any SSO user with a scope that matches a local user will be added to the same roles as the local user. For example, if local user sally is assigned to role:admin, and if an SSO user has a scope which happens to be named sally, that SSO user will also be assigned to role:admin.

An example of where this may be a problem is if your SSO provider is an SCM, and org members are automatically granted scopes named after the orgs. If a user can create or add themselves to an org in the SCM, they can gain the permissions of the local user with the same name.

To avoid ambiguity, if you are using local users and SSO, it is recommended to assign policies directly to local users, and not to assign roles to local users. In other words, instead of using g, my-local-user, role:admin, you should explicitly assign policies to my-local-user:

p, my-local-user, *, *, *, allow

Policy CSV Composition

It is possible to provide additional entries in the argocd-rbac-cm configmap to compose the final policy csv. In this case, the key must follow the pattern policy.<any string>.csv. Argo CD will concatenate all additional policies it finds with this pattern below the main one (‘policy.csv’). The order of additional provided policies are determined by the key string.

Example: if two additional policies are provided with keys policy.A.csv and policy.B.csv, it will first concatenate policy.A.csv and then policy.B.csv.

This is useful to allow composing policies in config management tools like Kustomize, Helm, etc.

The example below shows how a Kustomize patch can be provided in an overlay to add additional configuration to an existing RBAC ConfigMap.

apiVersion: v1
kind: ConfigMap
metadata:
  name: argocd-rbac-cm
  namespace: argocd
data:
  policy.tester-overlay.csv: |
    p, role:tester, applications, *, */*, allow
    p, role:tester, projects, *, *, allow
    g, my-org:team-qa, role:tester

Validating and testing your RBAC policies

If you want to ensure that your RBAC policies are working as expected, you can use the argocd admin settings rbac command to validate them. This tool allows you to test whether a certain role or subject can perform the requested action with a policy that’s not live yet in the system, i.e. from a local file or config map. Additionally, it can be used against the live RBAC configuration in the cluster your Argo CD is running in.

Validating a policy

To check whether your new policy configuration is valid and understood by Argo CD’s RBAC implementation, you can use the argocd admin settings rbac validate command.

Testing a policy

To test whether a role or subject (group or local user) has sufficient permissions to execute certain actions on certain resources, you can use the argocd admin settings rbac can command.