From 95a2fddfa8d5e6c850d32e89fefbb26f304365be Mon Sep 17 00:00:00 2001
From: Jens Langhammer <jens.langhammer@beryju.org>
Date: Mon, 20 Sep 2021 19:13:41 +0200
Subject: [PATCH] policies/expression: add ak_user_has_authenticator

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>
---
 authentik/flows/views.py                   |  7 +------
 authentik/policies/expression/evaluator.py | 16 ++++++++++++++++
 website/docs/policies/expression.mdx       | 17 +++++++++++++++++
 3 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/authentik/flows/views.py b/authentik/flows/views.py
index 830f46382..8a79d20bd 100644
--- a/authentik/flows/views.py
+++ b/authentik/flows/views.py
@@ -14,12 +14,7 @@ from django.utils.decorators import method_decorator
 from django.views.decorators.clickjacking import xframe_options_sameorigin
 from django.views.generic import View
 from drf_spectacular.types import OpenApiTypes
-from drf_spectacular.utils import (
-    OpenApiParameter,
-    OpenApiResponse,
-    PolymorphicProxySerializer,
-    extend_schema,
-)
+from drf_spectacular.utils import OpenApiParameter, PolymorphicProxySerializer, extend_schema
 from rest_framework.permissions import AllowAny
 from rest_framework.views import APIView
 from sentry_sdk import capture_exception
diff --git a/authentik/policies/expression/evaluator.py b/authentik/policies/expression/evaluator.py
index b8302b00a..25b70292e 100644
--- a/authentik/policies/expression/evaluator.py
+++ b/authentik/policies/expression/evaluator.py
@@ -3,8 +3,10 @@ from ipaddress import ip_address, ip_network
 from typing import TYPE_CHECKING, Optional
 
 from django.http import HttpRequest
+from django_otp import devices_for_user
 from structlog.stdlib import get_logger
 
+from authentik.core.models import User
 from authentik.flows.planner import PLAN_CONTEXT_SSO
 from authentik.lib.expression.evaluator import BaseEvaluator
 from authentik.lib.utils.http import get_client_ip
@@ -28,6 +30,7 @@ class PolicyEvaluator(BaseEvaluator):
         self._messages = []
         self._context["ak_logger"] = get_logger(policy_name)
         self._context["ak_message"] = self.expr_func_message
+        self._context["ak_user_has_authenticator"] = self.expr_func_user_has_authenticator
         self._context["ip_address"] = ip_address
         self._context["ip_network"] = ip_network
         self._filename = policy_name or "PolicyEvaluator"
@@ -36,6 +39,19 @@ class PolicyEvaluator(BaseEvaluator):
         """Wrapper to append to messages list, which is returned with PolicyResult"""
         self._messages.append(message)
 
+    def expr_func_user_has_authenticator(
+        self, user: User, device_type: Optional[str] = None
+    ) -> bool:
+        """Check if a user has any authenticator devices, optionally matching *device_type*"""
+        user_devices = devices_for_user(user)
+        if device_type:
+            for device in user_devices:
+                device_class = device.__class__.__name__.lower().replace("device", "")
+                if device_class == device_type:
+                    return True
+            return False
+        return len(user_devices) > 0
+
     def set_policy_request(self, request: PolicyRequest):
         """Update context based on policy request (if http request is given, update that too)"""
         # update website/docs/expressions/_objects.md
diff --git a/website/docs/policies/expression.mdx b/website/docs/policies/expression.mdx
index 4017a2c96..7403be683 100644
--- a/website/docs/policies/expression.mdx
+++ b/website/docs/policies/expression.mdx
@@ -25,6 +25,23 @@ ak_message("Access denied")
 return False
 ```
 
+### `ak_user_has_authenticator(user: User, device_type: Optional[str] = None)` (2021.9+)
+
+Check if a user has any authenticator devices. Only fully validated devices are counted.
+
+Optionally, you can filter a specific device type. The following options are valid:
+
+- `totp`
+- `duo`
+- `static`
+- `webauthn`
+
+Example:
+
+```python
+return ak_user_has_authenticator(request.user)
+```
+
 import Functions from '../expressions/_functions.md'
 
 <Functions />