core: add user flag to prevent users from changing their usernames

closes #1590

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

authentik/core/api/users.py

@@ -45,6 +45,7 @@ from authentik.core.api.used_by import UsedByMixin
 from authentik.core.api.utils import LinkSerializer, PassiveSerializer, is_dict
 from authentik.core.middleware import SESSION_IMPERSONATE_ORIGINAL_USER, SESSION_IMPERSONATE_USER
 from authentik.core.models import (
+    USER_ATTRIBUTE_CHANGE_USERNAME,
     USER_ATTRIBUTE_SA,
     USER_ATTRIBUTE_TOKEN_EXPIRING,
     Group,
@@ -113,14 +114,22 @@ class UserSelfSerializer(ModelSerializer):
             )
         )
     )
-    def get_groups(self, user: User):
+    def get_groups(self, _: User):
         """Return only the group names a user is member of"""
-        for group in user.ak_groups.all():
+        for group in self.instance.ak_groups.all():
             yield {
                 "name": group.name,
                 "pk": group.pk,
             }
 
+    def validate_username(self, username: str):
+        """Check if the user is allowed to change their username"""
+        if self.instance.group_attributes().get(USER_ATTRIBUTE_CHANGE_USERNAME, True):
+            return username
+        if username != self.instance.username:
+            raise ValidationError("Not allowed to change username.")
+        return username
+
     class Meta:
 
         model = User
@@ -337,7 +346,7 @@ class UserViewSet(UsedByMixin, ModelViewSet):
         # since it caches the full object
         if SESSION_IMPERSONATE_USER in request.session:
             request.session[SESSION_IMPERSONATE_USER] = new_user
-        serializer = SessionUserSerializer(data={"user": UserSelfSerializer(request.user).data})
+        serializer = SessionUserSerializer(data={"user": data.data})
         serializer.is_valid()
         return Response(serializer.data)
 

authentik/core/models.py

@@ -39,6 +39,7 @@ USER_ATTRIBUTE_DEBUG = "goauthentik.io/user/debug"
 USER_ATTRIBUTE_SA = "goauthentik.io/user/service-account"
 USER_ATTRIBUTE_SOURCES = "goauthentik.io/user/sources"
 USER_ATTRIBUTE_TOKEN_EXPIRING = "goauthentik.io/user/token-expires"  # nosec
+USER_ATTRIBUTE_CHANGE_USERNAME = "goauthentik.io/user/can-change-username"  # nosec
 USER_ATTRIBUTE_CAN_OVERRIDE_IP = "goauthentik.io/user/override-ips"
 
 GRAVATAR_URL = "https://secure.gravatar.com"

authentik/core/tests/test_users_api.py

@@ -2,7 +2,7 @@
 from django.urls.base import reverse
 from rest_framework.test import APITestCase
 
-from authentik.core.models import User
+from authentik.core.models import USER_ATTRIBUTE_CHANGE_USERNAME, User
 from authentik.flows.models import Flow, FlowDesignation
 from authentik.stages.email.models import EmailStage
 from authentik.tenants.models import Tenant
@@ -15,6 +15,24 @@ class TestUsersAPI(APITestCase):
         self.admin = User.objects.get(username="akadmin")
         self.user = User.objects.create(username="test-user")
 
+    def test_update_self(self):
+        """Test update_self"""
+        self.client.force_login(self.admin)
+        response = self.client.put(
+            reverse("authentik_api:user-update-self"), data={"username": "foo", "name": "foo"}
+        )
+        self.assertEqual(response.status_code, 200)
+
+    def test_update_self_username_denied(self):
+        """Test update_self"""
+        self.admin.attributes[USER_ATTRIBUTE_CHANGE_USERNAME] = False
+        self.admin.save()
+        self.client.force_login(self.admin)
+        response = self.client.put(
+            reverse("authentik_api:user-update-self"), data={"username": "foo", "name": "foo"}
+        )
+        self.assertEqual(response.status_code, 400)
+
     def test_metrics(self):
         """Test user's metrics"""
         self.client.force_login(self.admin)

authentik/sources/oauth/api/source_connection.py

@@ -38,3 +38,4 @@ class UserOAuthSourceConnectionViewSet(
     filterset_fields = ["source__slug"]
     permission_classes = [OwnerPermissions]
     filter_backends = [OwnerFilter, DjangoFilterBackend, OrderingFilter, SearchFilter]
+    ordering = ["source__slug"]

website/docs/expressions/_functions.md

@@ -32,7 +32,7 @@ return ak_is_group_member(request.user, name="test_group")
 
 Fetch a user matching `**filters`.
 
-Returns "None" if no user was found, otherwise [User](/docs/expressions/reference/user-object)
+Returns "None" if no user was found, otherwise [User](/docs/user-group/user)
 
 Example:
 

website/docs/policies/expression.mdx

@@ -53,7 +53,7 @@ import Objects from '../expressions/_objects.md'
 <Objects />
 
 - `request`: A PolicyRequest object, which has the following properties:
-    - `request.user`: The current user, against which the policy is applied. See [User](../expressions/reference/user-object.md)
+    - `request.user`: The current user, against which the policy is applied. See [User](../user-group/user.md#object-attributes)
     - `request.http_request`: The Django HTTP Request. See ([Django documentation](https://docs.djangoproject.com/en/3.0/ref/request-response/#httprequest-objects))
     - `request.obj`: A Django Model instance. This is only set if the policy is ran against an object.
     - `request.context`: A dictionary with dynamic data. This depends on the origin of the execution.
@@ -75,7 +75,7 @@ This includes the following:
 
 - `context['prompt_data']`: Data which has been saved from a prompt stage or an external source.
 - `context['application']`: The application the user is in the process of authorizing.
-- `context['pending_user']`: The currently pending user, see [User](/docs/expressions/reference/user-object)
+- `context['pending_user']`: The currently pending user, see [User](../user-group/user.md#object-attributes)
 - `context['auth_method']`: Authentication method set (this value is set by password stages)
 
     Depending on method, `context['auth_method_args']` is also set.

website/docs/property-mappings/expression.mdx

@@ -17,6 +17,6 @@ import Objects from '../expressions/_objects.md'
 
 <Objects />
 
-- `user`: The current user. This may be `None` if there is no contextual user. See ([User](../expressions/reference/user-object.md))
+- `user`: The current user. This may be `None` if there is no contextual user. See ([User](../user-group/user.md#object-attributes))
 - `request`: The current request. This may be `None` if there is no contextual request. See ([Django documentation](https://docs.djangoproject.com/en/3.0/ref/request-response/#httprequest-objects))
 - Other arbitrary arguments given by the provider, this is documented on the Provider/Source.

website/docs/user-group/user.md

@@ -1,7 +1,23 @@
 ---
-title: User Object
+title: User
 ---
 
+## Attributes
+
+### `goauthentik.io/user/can-change-username`
+
+Optional flag, when set to false prevents the user from changing their own username.
+
+### `goauthentik.io/user/token-expires`:
+
+Optional flag, when set to false, Tokens created by the user will not expire.
+
+### `goauthentik.io/user/debug`:
+
+See [Troubleshooting access problems](../troubleshooting/access.md), when set, the user gets a more detailed explanation of access decisions.
+
+## Object attributes
+
 The User object has the following attributes:
 
 - `username`: User's username.
@@ -11,8 +27,8 @@ The User object has the following attributes:
 - `is_active` Boolean field if user is active.
 - `date_joined` Date user joined/was created.
 - `password_change_date` Date password was last changed.
-- `attributes` Dynamic attributes.
-- `group_attributes` Merged attributes of all groups the user is member of and the user's own attributes.
+- `attributes` Dynamic attributes, see above
+- `group_attributes()` Merged attributes of all groups the user is member of and the user's own attributes.
 - `ak_groups` This is a queryset of all the user's groups.
 
     You can do additional filtering like

website/sidebars.js

@@ -8,6 +8,13 @@ module.exports = {
             type: "doc",
             id: "terminology",
         },
+        {
+            type: "category",
+            label: "Users & Groups",
+            items: [
+                "user-group/user"
+            ]
+        },
         {
             type: "category",
             label: "Installation",
@@ -145,17 +152,6 @@ module.exports = {
             label: "Property Mappings",
             items: ["property-mappings/index", "property-mappings/expression"],
         },
-        {
-            type: "category",
-            label: "Expressions",
-            items: [
-                {
-                    type: "category",
-                    label: "Reference",
-                    items: ["expressions/reference/user-object"],
-                },
-            ],
-        },
         {
             type: "category",
             label: "Events",