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