170 lines
		
	
	
		
			7.8 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			170 lines
		
	
	
		
			7.8 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| """passbook multi-factor authentication engine"""
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| from typing import List, Tuple
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| 
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| from django.contrib.auth import login
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| from django.contrib.auth.mixins import UserPassesTestMixin
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| from django.shortcuts import get_object_or_404, redirect, reverse
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| from django.utils.http import urlencode
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| from django.views.generic import View
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| from structlog import get_logger
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| 
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| from passbook.core.models import Factor, User
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| from passbook.core.views.utils import PermissionDeniedView
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| from passbook.lib.utils.reflection import class_to_path, path_to_class
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| from passbook.lib.utils.urls import is_url_absolute
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| from passbook.policies.engine import PolicyEngine
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| 
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| LOGGER = get_logger()
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| 
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| def _redirect_with_qs(view, get_query_set=None):
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|     """Wrapper to redirect whilst keeping GET Parameters"""
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|     target = reverse(view)
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|     if get_query_set:
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|         target += '?' + urlencode({key: value for key, value in get_query_set.items()})
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|     return redirect(target)
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| 
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| 
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| # Argument used to redirect user after login
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| NEXT_ARG_NAME = 'next'
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| 
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| class AuthenticationView(UserPassesTestMixin, View):
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|     """Wizard-like Multi-factor authenticator"""
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| 
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|     SESSION_FACTOR = 'passbook_factor'
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|     SESSION_PENDING_FACTORS = 'passbook_pending_factors'
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|     SESSION_PENDING_USER = 'passbook_pending_user'
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|     SESSION_USER_BACKEND = 'passbook_user_backend'
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|     SESSION_IS_SSO_LOGIN = 'passbook_sso_login'
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| 
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|     pending_user: User
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|     pending_factors: List[Tuple[str, str]] = []
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| 
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|     _current_factor_class: Factor
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| 
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|     current_factor: Factor
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| 
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|     # Allow only not authenticated users to login
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|     def test_func(self):
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|         return AuthenticationView.SESSION_PENDING_USER in self.request.session
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| 
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|     def handle_no_permission(self):
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|         # Function from UserPassesTestMixin
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|         if NEXT_ARG_NAME in self.request.GET:
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|             return redirect(self.request.GET.get(NEXT_ARG_NAME))
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|         if self.request.user.is_authenticated:
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|             return _redirect_with_qs('passbook_core:overview', self.request.GET)
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|         return _redirect_with_qs('passbook_core:auth-login', self.request.GET)
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| 
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|     def get_pending_factors(self):
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|         """Loading pending factors from Database or load from session variable"""
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|         # Write pending factors to session
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|         if AuthenticationView.SESSION_PENDING_FACTORS in self.request.session:
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|             return self.request.session[AuthenticationView.SESSION_PENDING_FACTORS]
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|         # Get an initial list of factors which are currently enabled
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|         # and apply to the current user. We check policies here and block the request
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|         _all_factors = Factor.objects.filter(enabled=True).order_by('order').select_subclasses()
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|         pending_factors = []
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|         for factor in _all_factors:
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|             LOGGER.debug("Checking if factor applies to user",
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|                          factor=factor, user=self.pending_user)
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|             policy_engine = PolicyEngine(factor.policies.all())
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|             policy_engine.for_user(self.pending_user).with_request(self.request).build()
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|             if policy_engine.passing:
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|                 pending_factors.append((factor.uuid.hex, factor.type))
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|                 LOGGER.debug("Factor applies", factor=factor, user=self.pending_user)
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|         return pending_factors
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| 
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|     def dispatch(self, request, *args, **kwargs):
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|         # Check if user passes test (i.e. SESSION_PENDING_USER is set)
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|         user_test_result = self.get_test_func()()
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|         if not user_test_result:
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|             return self.handle_no_permission()
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|         # Extract pending user from session (only remember uid)
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|         self.pending_user = get_object_or_404(
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|             User, id=self.request.session[AuthenticationView.SESSION_PENDING_USER])
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|         self.pending_factors = self.get_pending_factors()
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|         # Read and instantiate factor from session
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|         factor_uuid, factor_class = None, None
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|         if AuthenticationView.SESSION_FACTOR not in request.session:
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|             # Case when no factors apply to user, return error denied
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|             if not self.pending_factors:
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|                 # Case when user logged in from SSO provider and no more factors apply
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|                 if AuthenticationView.SESSION_IS_SSO_LOGIN in request.session:
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|                     LOGGER.debug("User authenticated with SSO, logging in...")
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|                     return self._user_passed()
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|                 return self.user_invalid()
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|             factor_uuid, factor_class = self.pending_factors[0]
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|         else:
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|             factor_uuid, factor_class = request.session[AuthenticationView.SESSION_FACTOR]
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|         # Lookup current factor object
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|         self.current_factor = Factor.objects.filter(uuid=factor_uuid).select_subclasses().first()
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|         # Instantiate Next Factor and pass request
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|         factor = path_to_class(factor_class)
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|         self._current_factor_class = factor(self)
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|         self._current_factor_class.pending_user = self.pending_user
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|         self._current_factor_class.request = request
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|         return super().dispatch(request, *args, **kwargs)
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| 
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|     def get(self, request, *args, **kwargs):
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|         """pass get request to current factor"""
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|         LOGGER.debug("Passing GET", view_class=class_to_path(self._current_factor_class.__class__))
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|         return self._current_factor_class.get(request, *args, **kwargs)
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| 
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|     def post(self, request, *args, **kwargs):
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|         """pass post request to current factor"""
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|         LOGGER.debug("Passing POST", view_class=class_to_path(self._current_factor_class.__class__))
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|         return self._current_factor_class.post(request, *args, **kwargs)
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| 
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|     def user_ok(self):
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|         """Redirect to next Factor"""
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|         LOGGER.debug("Factor passed",
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|                      factor_class=class_to_path(self._current_factor_class.__class__))
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|         # Remove passed factor from pending factors
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|         current_factor_tuple = (self.current_factor.uuid.hex,
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|                                 class_to_path(self._current_factor_class.__class__))
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|         if current_factor_tuple in self.pending_factors:
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|             self.pending_factors.remove(current_factor_tuple)
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|         next_factor = None
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|         if self.pending_factors:
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|             next_factor = self.pending_factors.pop()
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|             # Save updated pening_factor list to session
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|             self.request.session[AuthenticationView.SESSION_PENDING_FACTORS] = \
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|                 self.pending_factors
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|             self.request.session[AuthenticationView.SESSION_FACTOR] = next_factor
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|             LOGGER.debug("Rendering Factor", next_factor=next_factor)
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|             return _redirect_with_qs('passbook_core:auth-process', self.request.GET)
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|         # User passed all factors
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|         LOGGER.debug("User passed all factors, logging in")
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|         return self._user_passed()
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| 
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|     def user_invalid(self):
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|         """Show error message, user cannot login.
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|         This should only be shown if user authenticated successfully, but is disabled/locked/etc"""
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|         LOGGER.debug("User invalid")
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|         self.cleanup()
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|         return _redirect_with_qs('passbook_core:auth-denied', self.request.GET)
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| 
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|     def _user_passed(self):
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|         """User Successfully passed all factors"""
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|         backend = self.request.session[AuthenticationView.SESSION_USER_BACKEND]
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|         login(self.request, self.pending_user, backend=backend)
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|         LOGGER.debug("Logged in", user=self.pending_user)
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|         # Cleanup
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|         self.cleanup()
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|         next_param = self.request.GET.get(NEXT_ARG_NAME, None)
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|         if next_param and not is_url_absolute(next_param):
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|             return redirect(next_param)
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|         return _redirect_with_qs('passbook_core:overview')
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| 
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|     def cleanup(self):
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|         """Remove temporary data from session"""
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|         session_keys = [self.SESSION_FACTOR, self.SESSION_PENDING_FACTORS,
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|                         self.SESSION_PENDING_USER, self.SESSION_USER_BACKEND, ]
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|         for key in session_keys:
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|             if key in self.request.session:
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|                 del self.request.session[key]
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|         LOGGER.debug("Cleaned up sessions")
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| 
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| class FactorPermissionDeniedView(PermissionDeniedView):
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|     """User could not be authenticated"""
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