Add AnsibleBaseCsrfViewMiddleware and update SessionAuthentication to use get_setting

- Add AnsibleBaseCsrfViewMiddleware that reads CSRF_TRUSTED_ORIGINS using
  ansible_base.lib.utils.settings.get_setting instead of directly from Django settings
- Override all three cached properties (csrf_trusted_origins_hosts, allowed_origins_exact,
  allowed_origin_subdomains) to use get_setting for dynamic configuration
- Add AnsibleBaseCSRFCheck class that inherits from AnsibleBaseCsrfViewMiddleware
- Modify SessionAuthentication.enforce_csrf to use AnsibleBaseCSRFCheck instead of
  Django's default CSRFCheck
- Add comprehensive tests for both middleware and session authentication CSRF functionality
- Enables CSRF_TRUSTED_ORIGINS to be dynamically loaded from various sources via
  ANSIBLE_BASE_SETTINGS_FUNCTION while maintaining backward compatibility

Author: TheRealHaoLiu

ansible_base/authentication/middleware.py

@@ -1,11 +1,16 @@
 import logging
+from collections import defaultdict
+from urllib.parse import urlsplit
 
 from django.contrib.auth import BACKEND_SESSION_KEY
 from django.core.exceptions import ImproperlyConfigured
+from django.middleware.csrf import CsrfViewMiddleware
 from django.utils.deprecation import MiddlewareMixin
+from django.utils.functional import cached_property
 from social_django.middleware import SocialAuthExceptionMiddleware
 
 from ansible_base.authentication.authenticator_plugins.utils import get_authenticator_plugins
+from ansible_base.lib.utils.settings import get_setting
 
 logger = logging.getLogger('ansible_base.authentication.middleware')
 
@@ -51,3 +56,46 @@ def get_redirect_uri(self, request, exception):
         backend_name = getattr(backend, "name", "unknown-backend")
         logger.error(f"Auth failure for backend {backend_name} - {repr(exception)}, redirecting to {error_url}")
         return error_url
+
+
+class AnsibleBaseCsrfViewMiddleware(CsrfViewMiddleware):
+    """
+    CsrfViewMiddleware subclass that reads CSRF_TRUSTED_ORIGINS using
+    ansible_base.lib.utils.settings.get_setting instead of directly from
+    Django settings.
+
+    This allows the setting to be dynamically loaded from various sources
+    as configured by the ANSIBLE_BASE_SETTINGS_FUNCTION setting.
+
+    Overrides all cached properties that access settings.CSRF_TRUSTED_ORIGINS
+    to use get_setting instead.
+    """
+
+    @cached_property
+    def csrf_trusted_origins_hosts(self):
+        """
+        Override to use get_setting instead of settings.CSRF_TRUSTED_ORIGINS.
+        """
+        csrf_trusted_origins = get_setting('CSRF_TRUSTED_ORIGINS', [])
+        return [urlsplit(origin).netloc.lstrip("*") for origin in csrf_trusted_origins]
+
+    @cached_property
+    def allowed_origins_exact(self):
+        """
+        Override to use get_setting instead of settings.CSRF_TRUSTED_ORIGINS.
+        """
+        csrf_trusted_origins = get_setting('CSRF_TRUSTED_ORIGINS', [])
+        return {origin for origin in csrf_trusted_origins if "*" not in origin}
+
+    @cached_property
+    def allowed_origin_subdomains(self):
+        """
+        Override to use get_setting instead of settings.CSRF_TRUSTED_ORIGINS.
+        A mapping of allowed schemes to list of allowed netlocs, where all
+        subdomains of the netloc are allowed.
+        """
+        csrf_trusted_origins = get_setting('CSRF_TRUSTED_ORIGINS', [])
+        allowed_origin_subdomains = defaultdict(list)
+        for parsed in (urlsplit(origin) for origin in csrf_trusted_origins if "*" in origin):
+            allowed_origin_subdomains[parsed.scheme].append(parsed.netloc.lstrip("*"))
+        return allowed_origin_subdomains

ansible_base/authentication/session.py

@@ -1,10 +1,49 @@
-from rest_framework import authentication
+from rest_framework import authentication, exceptions
+
+from ansible_base.authentication.middleware import (
+    AnsibleBaseCsrfViewMiddleware,
+)
+
+
+class AnsibleBaseCSRFCheck(AnsibleBaseCsrfViewMiddleware):
+    """
+    Custom CSRF check class that uses AnsibleBaseCsrfViewMiddleware
+    instead of Django's CsrfViewMiddleware for CSRF validation.
+
+    This ensures that CSRF_TRUSTED_ORIGINS is read using get_setting
+    instead of directly from Django settings.
+    """
+
+    def _reject(self, request, reason):
+        # Return the failure reason instead of an HttpResponse
+        return reason
 
 
 class SessionAuthentication(authentication.SessionAuthentication):
     """
     This class allows us to fail with a 401 if the user is not authenticated.
+
+    Uses AnsibleBaseCsrfViewMiddleware for CSRF checking instead of Django's
+    default CsrfViewMiddleware, allowing CSRF_TRUSTED_ORIGINS to be read
+    dynamically using get_setting.
     """
 
     def authenticate_header(self, request):
         return "Session"
+
+    def enforce_csrf(self, request):
+        """
+        Enforce CSRF validation for session based authentication using
+        AnsibleBaseCsrfViewMiddleware instead of Django's CsrfViewMiddleware.
+        """
+
+        def dummy_get_response(request):  # pragma: no cover
+            return None
+
+        check = AnsibleBaseCSRFCheck(dummy_get_response)
+        # populates request.META['CSRF_COOKIE'], which is used in process_view()
+        check.process_request(request)
+        reason = check.process_view(request, None, (), {})
+        if reason:
+            # CSRF failed, bail with explicit error message
+            raise exceptions.PermissionDenied('CSRF Failed: %s' % reason)

test_app/tests/authentication/test_middleware.py

@@ -1,7 +1,16 @@
+from unittest.mock import patch
+
 from django.conf import settings
 from social_core.exceptions import AuthException
 
-from ansible_base.authentication.middleware import SocialExceptionHandlerMiddleware
+from ansible_base.authentication.middleware import (
+    AnsibleBaseCsrfViewMiddleware,
+    SocialExceptionHandlerMiddleware,
+)
+from ansible_base.authentication.session import (
+    AnsibleBaseCSRFCheck,
+    SessionAuthentication,
+)
 
 
 def test_social_exception_handler_mw():
@@ -21,3 +30,138 @@ def __init__(self):
     mw = SocialExceptionHandlerMiddleware(None)
     url = mw.get_redirect_uri(Request(), AuthException("test"))
     assert url == "/?auth_failed"
+
+
+def test_ansible_base_csrf_view_middleware_csrf_trusted_origins_hosts():
+    """Test that csrf_trusted_origins_hosts uses get_setting."""
+    test_origins = ['https://example.com', 'https://*.test.com']
+
+    with patch('ansible_base.authentication.middleware.get_setting') as mock_get_setting:
+        mock_get_setting.return_value = test_origins
+
+        middleware = AnsibleBaseCsrfViewMiddleware(lambda request: None)
+        result = middleware.csrf_trusted_origins_hosts
+
+        mock_get_setting.assert_called_once_with('CSRF_TRUSTED_ORIGINS', [])
+        # Should strip * from netloc
+        assert result == ['example.com', '.test.com']
+
+
+def test_ansible_base_csrf_view_middleware_allowed_origins_exact():
+    """Test that allowed_origins_exact uses get_setting."""
+    test_origins = ['https://example.com', 'https://*.test.com']
+
+    with patch('ansible_base.authentication.middleware.get_setting') as mock_get_setting:
+        mock_get_setting.return_value = test_origins
+
+        middleware = AnsibleBaseCsrfViewMiddleware(lambda request: None)
+        result = middleware.allowed_origins_exact
+
+        mock_get_setting.assert_called_once_with('CSRF_TRUSTED_ORIGINS', [])
+        # Should only include origins without *
+        assert result == {'https://example.com'}
+
+
+def test_ansible_base_csrf_view_middleware_allowed_origin_subdomains():
+    """Test that allowed_origin_subdomains uses get_setting."""
+    test_origins = ['https://*.example.com', 'http://*.test.com']
+
+    with patch('ansible_base.authentication.middleware.get_setting') as mock_get_setting:
+        mock_get_setting.return_value = test_origins
+
+        middleware = AnsibleBaseCsrfViewMiddleware(lambda request: None)
+        result = middleware.allowed_origin_subdomains
+
+        mock_get_setting.assert_called_once_with('CSRF_TRUSTED_ORIGINS', [])
+        # Should group by scheme and strip *
+        expected = {'https': ['.example.com'], 'http': ['.test.com']}
+        assert dict(result) == expected
+
+
+def test_ansible_base_csrf_view_middleware_default_value():
+    """Test that middleware returns empty/default values when setting is empty."""
+    with patch('ansible_base.authentication.middleware.get_setting') as mock_get_setting:
+        mock_get_setting.return_value = []
+
+        middleware = AnsibleBaseCsrfViewMiddleware(lambda request: None)
+
+        # Test all three properties
+        assert middleware.csrf_trusted_origins_hosts == []
+        assert middleware.allowed_origins_exact == set()
+        assert dict(middleware.allowed_origin_subdomains) == {}
+
+        # get_setting should be called three times (once for each property)
+        assert mock_get_setting.call_count == 3
+
+
+def test_ansible_base_csrf_check_inherits_from_ansible_base_csrf_view_middleware():
+    """Test that AnsibleBaseCSRFCheck inherits from AnsibleBaseCsrfViewMiddleware."""
+    csrf_check = AnsibleBaseCSRFCheck(lambda request: None)
+    assert isinstance(csrf_check, AnsibleBaseCsrfViewMiddleware)
+
+
+def test_ansible_base_csrf_check_reject_method():
+    """Test that AnsibleBaseCSRFCheck._reject returns the reason."""
+    csrf_check = AnsibleBaseCSRFCheck(lambda request: None)
+    reason = "Test CSRF failure reason"
+    result = csrf_check._reject(None, reason)
+    assert result == reason
+
+
+def test_session_authentication_uses_ansible_base_csrf_check():
+    """Test that SessionAuthentication uses AnsibleBaseCSRFCheck for CSRF validation."""
+    from unittest.mock import Mock
+
+    # Create a mock request with an authenticated user
+    mock_request = Mock()
+    mock_request._request = Mock()
+    mock_request._request.user = Mock()
+    mock_request._request.user.is_active = True
+
+    # Mock the AnsibleBaseCSRFCheck to track its usage
+    with patch('ansible_base.authentication.session.AnsibleBaseCSRFCheck') as mock_csrf_check_class:
+        mock_csrf_check = Mock()
+        mock_csrf_check.process_request.return_value = None
+        mock_csrf_check.process_view.return_value = None  # No CSRF error
+        mock_csrf_check_class.return_value = mock_csrf_check
+
+        # Create SessionAuthentication instance and call enforce_csrf
+        session_auth = SessionAuthentication()
+        session_auth.enforce_csrf(mock_request)
+
+        # Verify AnsibleBaseCSRFCheck was instantiated
+        mock_csrf_check_class.assert_called_once()
+
+        # Verify process_request and process_view were called
+        mock_csrf_check.process_request.assert_called_once_with(mock_request)
+        mock_csrf_check.process_view.assert_called_once_with(mock_request, None, (), {})
+
+
+def test_session_authentication_csrf_failure_raises_permission_denied():
+    """Test that SessionAuthentication raises PermissionDenied when CSRF fails."""
+    from unittest.mock import Mock
+
+    from rest_framework.exceptions import PermissionDenied
+
+    # Create a mock request with an authenticated user
+    mock_request = Mock()
+    mock_request._request = Mock()
+    mock_request._request.user = Mock()
+    mock_request._request.user.is_active = True
+
+    # Mock the AnsibleBaseCSRFCheck to return a CSRF failure reason
+    with patch('ansible_base.authentication.session.AnsibleBaseCSRFCheck') as mock_csrf_check_class:
+        mock_csrf_check = Mock()
+        mock_csrf_check.process_request.return_value = None
+        mock_csrf_check.process_view.return_value = "CSRF token missing"  # CSRF error
+        mock_csrf_check_class.return_value = mock_csrf_check
+
+        # Create SessionAuthentication instance and call enforce_csrf
+        session_auth = SessionAuthentication()
+
+        # Should raise PermissionDenied with the CSRF failure reason
+        try:
+            session_auth.enforce_csrf(mock_request)
+            assert False, "Expected PermissionDenied to be raised"
+        except PermissionDenied as e:
+            assert "CSRF Failed: CSRF token missing" in str(e)