flows: fix redirect when un-authenticated user uses external authentication (#416)

* flows: add PLAN_CONTEXT_REDIRECT so final redirect can be set from within flow

* sources/*: use PLAN_CONTEXT_REDIRECT

* flows: fallback when flow plan is empty

authentik/flows/planner.py

@@ -19,6 +19,7 @@ LOGGER = get_logger()
 
 PLAN_CONTEXT_PENDING_USER = "pending_user"
 PLAN_CONTEXT_SSO = "is_sso"
+PLAN_CONTEXT_REDIRECT = "redirect"
 PLAN_CONTEXT_APPLICATION = "application"
 
 

authentik/flows/views.py

@@ -21,7 +21,12 @@ from authentik.audit.models import cleanse_dict
 from authentik.core.models import USER_ATTRIBUTE_DEBUG
 from authentik.flows.exceptions import EmptyFlowException, FlowNonApplicableException
 from authentik.flows.models import ConfigurableStage, Flow, FlowDesignation, Stage
-from authentik.flows.planner import PLAN_CONTEXT_PENDING_USER, FlowPlan, FlowPlanner
+from authentik.flows.planner import (
+    PLAN_CONTEXT_PENDING_USER,
+    PLAN_CONTEXT_REDIRECT,
+    FlowPlan,
+    FlowPlanner,
+)
 from authentik.lib.utils.reflection import class_to_path
 from authentik.lib.utils.urls import is_url_absolute, redirect_with_qs
 from authentik.policies.http import AccessDeniedResponse
@@ -145,6 +150,10 @@ class FlowExecutorView(View):
         """User Successfully passed all stages"""
         # Since this is wrapped by the ExecutorShell, the next argument is saved in the session
         # extract the next param before cancel as that cleans it
+        next_param = None
+        if self.plan:
+            next_param = self.plan.context.get(PLAN_CONTEXT_REDIRECT)
+        if not next_param:
             next_param = self.request.session.get(SESSION_KEY_GET, {}).get(
                 NEXT_ARG_NAME, "authentik_core:shell"
             )

authentik/sources/oauth/views/callback.py

@@ -15,10 +15,11 @@ from authentik.core.models import User
 from authentik.flows.models import Flow, in_memory_stage
 from authentik.flows.planner import (
     PLAN_CONTEXT_PENDING_USER,
+    PLAN_CONTEXT_REDIRECT,
     PLAN_CONTEXT_SSO,
     FlowPlanner,
 )
-from authentik.flows.views import SESSION_KEY_PLAN
+from authentik.flows.views import NEXT_ARG_NAME, SESSION_KEY_GET, SESSION_KEY_PLAN
 from authentik.lib.utils.urls import redirect_with_qs
 from authentik.policies.utils import delete_none_keys
 from authentik.sources.oauth.auth import AuthorizedServiceBackend
@@ -135,11 +136,17 @@ class OAuthCallback(OAuthClientMixin, View):
 
     def handle_login_flow(self, flow: Flow, **kwargs) -> HttpResponse:
         """Prepare Authentication Plan, redirect user FlowExecutor"""
+        # Ensure redirect is carried through when user was trying to
+        # authorize application
+        final_redirect = self.request.session.get(SESSION_KEY_GET, {}).get(
+            NEXT_ARG_NAME, "authentik_core:shell"
+        )
         kwargs.update(
             {
                 # Since we authenticate the user by their token, they have no backend set
                 PLAN_CONTEXT_AUTHENTICATION_BACKEND: "django.contrib.auth.backends.ModelBackend",
                 PLAN_CONTEXT_SSO: True,
+                PLAN_CONTEXT_REDIRECT: final_redirect,
             }
         )
         # We run the Flow planner here so we can pass the Pending user in the context

authentik/sources/saml/processors/response.py

@@ -13,10 +13,11 @@ from authentik.core.models import User
 from authentik.flows.models import Flow
 from authentik.flows.planner import (
     PLAN_CONTEXT_PENDING_USER,
+    PLAN_CONTEXT_REDIRECT,
     PLAN_CONTEXT_SSO,
     FlowPlanner,
 )
-from authentik.flows.views import SESSION_KEY_PLAN
+from authentik.flows.views import NEXT_ARG_NAME, SESSION_KEY_GET, SESSION_KEY_PLAN
 from authentik.lib.utils.urls import redirect_with_qs
 from authentik.policies.utils import delete_none_keys
 from authentik.sources.saml.exceptions import (
@@ -54,11 +55,14 @@ class ResponseProcessor:
     _root: Any
     _root_xml: str
 
+    _http_request: HttpRequest
+
     def __init__(self, source: SAMLSource):
         self._source = source
 
     def parse(self, request: HttpRequest):
         """Check if `request` contains SAML Response data, parse and validate it."""
+        self._http_request = request
         # First off, check if we have any SAML Data at all.
         raw_response = request.POST.get("SAMLResponse", None)
         if not raw_response:
@@ -187,6 +191,11 @@ class ResponseProcessor:
 
         name_id_filter = self._get_name_id_filter()
         matching_users = User.objects.filter(**name_id_filter)
+        # Ensure redirect is carried through when user was trying to
+        # authorize application
+        final_redirect = self._http_request.session.get(SESSION_KEY_GET, {}).get(
+            NEXT_ARG_NAME, "authentik_core:shell"
+        )
         if matching_users.exists():
             # User exists already, switch to authentication flow
             return self._flow_response(
@@ -195,6 +204,7 @@ class ResponseProcessor:
                 **{
                     PLAN_CONTEXT_PENDING_USER: matching_users.first(),
                     PLAN_CONTEXT_AUTHENTICATION_BACKEND: DEFAULT_BACKEND,
+                    PLAN_CONTEXT_REDIRECT: final_redirect,
                 },
             )
         return self._flow_response(