Add support for auth.oidc.allowed_user_groups (#667) (#668)

Signed-off-by: Michael Tupitsyn <michael.tupitsyn@gmail.com>

docs/documentation/configuration/examples.md

@@ -144,6 +144,9 @@ auth:
       extra_scopes:
         - https://www.googleapis.com/auth/userinfo.email
         - https://www.googleapis.com/auth/userinfo.profile
+      allowed_user_groups:
+        - the-admin-group
+        - vpn-users
       field_map:
         user_identifier: sub
         email: email
@@ -201,6 +204,9 @@ auth:
         - email
         - profile
         - i-want-some-groups
+      allowed_user_groups:
+        - admin-group-name
+        - vpn-users
       field_map:
         email: email
         firstname: name

docs/documentation/configuration/overview.md

@@ -561,6 +561,10 @@ Below are the properties for each OIDC provider entry inside `auth.oidc`:
 - **Default:** *(empty)*
 - **Description:** A list of allowlisted domains. Only users with email addresses in these domains can log in or register. This is useful for restricting access to specific organizations or groups.
 
+#### `allowed_user_groups`
+- **Default:** *(empty)*
+- **Description:** A list of allowlisted user groups. If configured, at least one entry in the mapped `user_groups` claim must match one of these values.
+
 #### `field_map`
 - **Default:** *(empty)*
 - **Description:** Maps OIDC claims to WireGuard Portal user fields. 
@@ -639,6 +643,10 @@ Below are the properties for each OAuth provider entry inside `auth.oauth`:
 - **Default:** *(empty)*
 - **Description:** A list of allowlisted domains. Only users with email addresses in these domains can log in or register. This is useful for restricting access to specific organizations or groups.
 
+#### `allowed_user_groups`
+- **Default:** *(empty)*
+- **Description:** A list of allowlisted user groups. If configured, at least one entry in the mapped `user_groups` claim must match one of these values.
+
 #### `field_map`
 - **Default:** *(empty)*
 - **Description:** Maps OAuth attributes to WireGuard Portal fields.

docs/documentation/usage/authentication.md

@@ -66,6 +66,40 @@ auth:
         - "outlook.com"
 ```
 
+#### Limiting Login to Specific User Groups
+
+You can limit the login to specific user groups by setting the `allowed_user_groups` property for OAuth2 or OIDC providers.
+If this property is not empty, the user's `user_groups` claim must contain at least one matching group.
+
+To use this feature, ensure your group claim is mapped via `field_map.user_groups`.
+
+```yaml
+auth:
+  oidc:
+    - provider_name: "oidc1"
+      # ... other settings
+      allowed_user_groups:
+        - "wg-users"
+        - "wg-admins"
+      field_map:
+        user_groups: "groups"
+```
+
+If `allowed_user_groups` is configured and the authenticated user has no matching group in `user_groups`, login is denied.
+
+Minimal deny-by-group example:
+
+```yaml
+auth:
+  oauth:
+    - provider_name: "oauth1"
+      # ... other settings
+      allowed_user_groups:
+        - "vpn-users"
+      field_map:
+        user_groups: "groups"
+```
+
 #### Limit Login to Existing Users
 
 You can limit the login to existing users only by setting the `registration_enabled` property to `false` for OAuth2 or OIDC providers.