providers/oauth2: clip device authorization scope against the provider's ScopeMapping set (cherry-pick #21701 to version-2025.12) (#21798)

Cherry-pick #21701 to version-2025.12 (with conflicts)

This cherry-pick has conflicts that need manual resolution.

Original PR: #21701
Original commit: cce646b132

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

# Conflicts:
#	authentik/providers/oauth2/tests/test_device_backchannel.py
#	authentik/providers/oauth2/views/device_backchannel.py

Co-authored-by: Sai Asish Y <say.apm35@gmail.com>

authentik/providers/oauth2/tests/test_device_backchannel.py

@@ -5,10 +5,11 @@ from json import loads
 
 from django.urls import reverse
 
+from authentik.blueprints.tests import apply_blueprint
 from authentik.core.models import Application
 from authentik.core.tests.utils import create_test_flow
 from authentik.lib.generators import generate_id
-from authentik.providers.oauth2.models import OAuth2Provider
+from authentik.providers.oauth2.models import DeviceToken, OAuth2Provider, ScopeMapping
 from authentik.providers.oauth2.tests.utils import OAuthTestCase
 
 
@@ -96,3 +97,57 @@ class TesOAuth2DeviceBackchannel(OAuthTestCase):
         self.assertEqual(res.status_code, 200)
         body = loads(res.content.decode())
         self.assertEqual(body["expires_in"], 60)
+
+    @apply_blueprint("system/providers-oauth2.yaml")
+    def test_backchannel_scopes(self):
+        """Test backchannel"""
+        self.provider.property_mappings.set(
+            ScopeMapping.objects.filter(
+                managed__in=[
+                    "goauthentik.io/providers/oauth2/scope-openid",
+                    "goauthentik.io/providers/oauth2/scope-email",
+                    "goauthentik.io/providers/oauth2/scope-profile",
+                ]
+            )
+        )
+        creds = b64encode(f"{self.provider.client_id}:".encode()).decode()
+        res = self.client.post(
+            reverse("authentik_providers_oauth2:device"),
+            HTTP_AUTHORIZATION=f"Basic {creds}",
+            data={"scope": "openid email"},
+        )
+        self.assertEqual(res.status_code, 200)
+        body = loads(res.content.decode())
+        self.assertEqual(body["expires_in"], 60)
+        token = DeviceToken.objects.filter(device_code=body["device_code"]).first()
+        self.assertIsNotNone(token)
+        self.assertEqual(len(token.scope), 2)
+        self.assertIn("openid", token.scope)
+        self.assertIn("email", token.scope)
+
+    @apply_blueprint("system/providers-oauth2.yaml")
+    def test_backchannel_scopes_extra(self):
+        """Test backchannel"""
+        self.provider.property_mappings.set(
+            ScopeMapping.objects.filter(
+                managed__in=[
+                    "goauthentik.io/providers/oauth2/scope-openid",
+                    "goauthentik.io/providers/oauth2/scope-email",
+                    "goauthentik.io/providers/oauth2/scope-profile",
+                ]
+            )
+        )
+        creds = b64encode(f"{self.provider.client_id}:".encode()).decode()
+        res = self.client.post(
+            reverse("authentik_providers_oauth2:device"),
+            HTTP_AUTHORIZATION=f"Basic {creds}",
+            data={"scope": "openid email foo"},
+        )
+        self.assertEqual(res.status_code, 200)
+        body = loads(res.content.decode())
+        self.assertEqual(body["expires_in"], 60)
+        token = DeviceToken.objects.filter(device_code=body["device_code"]).first()
+        self.assertIsNotNone(token)
+        self.assertEqual(len(token.scope), 2)
+        self.assertIn("openid", token.scope)
+        self.assertIn("email", token.scope)

authentik/providers/oauth2/views/device_backchannel.py

@@ -15,7 +15,7 @@ from authentik.core.models import Application
 from authentik.lib.config import CONFIG
 from authentik.lib.utils.time import timedelta_from_string
 from authentik.providers.oauth2.errors import DeviceCodeError
-from authentik.providers.oauth2.models import DeviceToken, OAuth2Provider
+from authentik.providers.oauth2.models import DeviceToken, OAuth2Provider, ScopeMapping
 from authentik.providers.oauth2.utils import TokenResponse, extract_client_auth
 from authentik.providers.oauth2.views.device_init import QS_KEY_CODE
 
@@ -28,7 +28,7 @@ class DeviceView(View):
 
     client_id: str
     provider: OAuth2Provider
-    scopes: list[str] = []
+    scopes: set[str] = []
 
     def parse_request(self):
         """Parse incoming request"""
@@ -44,7 +44,21 @@ class DeviceView(View):
             raise DeviceCodeError("invalid_client") from None
         self.provider = provider
         self.client_id = client_id
-        self.scopes = self.request.POST.get("scope", "").split(" ")
+
+        scopes_to_check = set(self.request.POST.get("scope", "").split())
+        default_scope_names = set(
+            ScopeMapping.objects.filter(provider__in=[self.provider]).values_list(
+                "scope_name", flat=True
+            )
+        )
+        self.scopes = scopes_to_check
+        if not scopes_to_check.issubset(default_scope_names):
+            LOGGER.info(
+                "Application requested scopes not configured, setting to overlap",
+                scope_allowed=default_scope_names,
+                scope_given=self.scopes,
+            )
+            self.scopes = self.scopes.intersection(default_scope_names)
 
     def dispatch(self, request: HttpRequest, *args, **kwargs) -> HttpResponse:
         throttle = AnonRateThrottle()