import logging from typing import Any, Dict, List, Set, Tuple, Optional from apiclient.sample_tools import client as googleapiclient from django_auth_ldap.backend import LDAPBackend, _LDAPUser import django.contrib.auth from django.contrib.auth.backends import RemoteUserBackend from django.conf import settings from django.http import HttpResponse from oauth2client.crypt import AppIdentityError from social_core.backends.github import GithubOAuth2, GithubOrganizationOAuth2, \ GithubTeamOAuth2 from social_core.utils import handle_http_errors from social_core.exceptions import AuthFailed, SocialAuthBaseException from social_django.models import DjangoStorage from social_django.strategy import DjangoStrategy from zerver.lib.actions import do_create_user from zerver.lib.request import JsonableError from zerver.lib.subdomains import user_matches_subdomain, get_subdomain from zerver.lib.users import check_full_name from zerver.models import UserProfile, Realm, get_user_profile_by_id, \ remote_user_to_email, email_to_username, get_realm, get_user def pad_method_dict(method_dict: Dict[str, bool]) -> Dict[str, bool]: """Pads an authentication methods dict to contain all auth backends supported by the software, regardless of whether they are configured on this server""" for key in AUTH_BACKEND_NAME_MAP: if key not in method_dict: method_dict[key] = False return method_dict def auth_enabled_helper(backends_to_check: List[str], realm: Optional[Realm]) -> bool: if realm is not None: enabled_method_dict = realm.authentication_methods_dict() pad_method_dict(enabled_method_dict) else: enabled_method_dict = dict((method, True) for method in Realm.AUTHENTICATION_FLAGS) pad_method_dict(enabled_method_dict) for supported_backend in django.contrib.auth.get_backends(): for backend_name in backends_to_check: backend = AUTH_BACKEND_NAME_MAP[backend_name] if enabled_method_dict[backend_name] and isinstance(supported_backend, backend): return True return False def ldap_auth_enabled(realm: Optional[Realm]=None) -> bool: return auth_enabled_helper(['LDAP'], realm) def email_auth_enabled(realm: Optional[Realm]=None) -> bool: return auth_enabled_helper(['Email'], realm) def password_auth_enabled(realm: Optional[Realm]=None) -> bool: return ldap_auth_enabled(realm) or email_auth_enabled(realm) def dev_auth_enabled(realm: Optional[Realm]=None) -> bool: return auth_enabled_helper(['Dev'], realm) def google_auth_enabled(realm: Optional[Realm]=None) -> bool: return auth_enabled_helper(['Google'], realm) def github_auth_enabled(realm: Optional[Realm]=None) -> bool: return auth_enabled_helper(['GitHub'], realm) def remote_auth_enabled(realm: Optional[Realm]=None) -> bool: return auth_enabled_helper(['RemoteUser'], realm) def any_oauth_backend_enabled(realm: Optional[Realm]=None) -> bool: """Used by the login page process to determine whether to show the 'OR' for login with Google""" return auth_enabled_helper(['GitHub', 'Google'], realm) def require_email_format_usernames(realm: Optional[Realm]=None) -> bool: if ldap_auth_enabled(realm): if settings.LDAP_EMAIL_ATTR or settings.LDAP_APPEND_DOMAIN: return False return True def common_get_active_user(email: str, realm: Realm, return_data: Dict[str, Any]=None) -> Optional[UserProfile]: try: user_profile = get_user(email, realm) except UserProfile.DoesNotExist: # If the user doesn't have an account in the target realm, we # check whether they might have an account in another realm, # and if so, provide a helpful error message via # `invalid_subdomain`. if not UserProfile.objects.filter(email__iexact=email).exists(): return None if return_data is not None: return_data['invalid_subdomain'] = True return None if not user_profile.is_active: if return_data is not None: if user_profile.is_mirror_dummy: # Record whether it's a mirror dummy account return_data['is_mirror_dummy'] = True return_data['inactive_user'] = True return None if user_profile.realm.deactivated: if return_data is not None: return_data['inactive_realm'] = True return None return user_profile class ZulipAuthMixin: def get_user(self, user_profile_id: int) -> Optional[UserProfile]: """ Get a UserProfile object from the user_profile_id. """ try: return get_user_profile_by_id(user_profile_id) except UserProfile.DoesNotExist: return None class SocialAuthMixin(ZulipAuthMixin): auth_backend_name = None # type: str def get_email_address(self, *args: Any, **kwargs: Any) -> str: raise NotImplementedError def get_full_name(self, *args: Any, **kwargs: Any) -> str: raise NotImplementedError def get_authenticated_user(self, *args: Any, **kwargs: Any) -> Optional[UserProfile]: raise NotImplementedError @handle_http_errors def do_auth(self, *args: Any, **kwargs: Any) -> Optional[HttpResponse]: """ This function is called once the authentication workflow is complete. We override this function to: 1. Inject `return_data` and `realm_subdomain` kwargs. These will be used by `authenticate()` functions of backends to make the decision. 2. Call the proper authentication function to get the user in `get_authenticated_user`. The actual decision on authentication is done in SocialAuthMixin._common_authenticate(). SocialAuthMixin.get_authenticated_user is expected to be overridden by the derived class to add custom logic for authenticating the user and returning the user. """ kwargs['return_data'] = {} subdomain = self.strategy.session_get('subdomain') # type: ignore # `strategy` comes from Python Social Auth. realm = get_realm(subdomain) kwargs['realm'] = realm user_profile = self.get_authenticated_user(*args, **kwargs) return self.process_do_auth(user_profile, *args, **kwargs) def authenticate(self, realm: Optional[Realm]=None, storage: Optional[DjangoStorage]=None, strategy: Optional[DjangoStrategy]=None, user: Optional[Dict[str, Any]]=None, return_data: Optional[Dict[str, Any]]=None, response: Optional[Dict[str, Any]]=None, backend: Optional[GithubOAuth2]=None ) -> Optional[UserProfile]: """ Django decides which `authenticate` to call by inspecting the arguments. So it's better to create `authenticate` function with well defined arguments. Keeping this function separate so that it can easily be overridden. """ if user is None: user = {} assert return_data is not None assert response is not None return self._common_authenticate(self, realm=realm, storage=storage, strategy=strategy, user=user, return_data=return_data, response=response, backend=backend) def _common_authenticate(self, *args: Any, **kwargs: Any) -> Optional[UserProfile]: return_data = kwargs.get('return_data', {}) realm = kwargs.get("realm") if realm is None: return None if not auth_enabled_helper([self.auth_backend_name], realm): return_data["auth_backend_disabled"] = True return None email_address = self.get_email_address(*args, **kwargs) if not email_address: return_data['invalid_email'] = True return None return_data["valid_attestation"] = True return common_get_active_user(email_address, realm, return_data) def process_do_auth(self, user_profile: UserProfile, *args: Any, **kwargs: Any) -> Optional[HttpResponse]: # These functions need to be imported here to avoid cyclic # dependency. from zerver.views.auth import (login_or_register_remote_user, redirect_to_subdomain_login_url, redirect_and_log_into_subdomain) return_data = kwargs.get('return_data', {}) inactive_user = return_data.get('inactive_user') inactive_realm = return_data.get('inactive_realm') invalid_subdomain = return_data.get('invalid_subdomain') invalid_email = return_data.get('invalid_email') if inactive_user or inactive_realm: # Redirect to login page. We can't send to registration # workflow with these errors. We will redirect to login page. return None if invalid_email: # In case of invalid email, we will end up on registration page. # This seems better than redirecting to login page. logging.warning( "{} got invalid email argument.".format(self.auth_backend_name) ) return None strategy = self.strategy # type: ignore # This comes from Python Social Auth. request = strategy.request email_address = self.get_email_address(*args, **kwargs) full_name = self.get_full_name(*args, **kwargs) is_signup = strategy.session_get('is_signup') == '1' redirect_to = strategy.session_get('next') mobile_flow_otp = strategy.session_get('mobile_flow_otp') subdomain = strategy.session_get('subdomain') assert subdomain is not None if mobile_flow_otp is not None: return login_or_register_remote_user(request, email_address, user_profile, full_name, invalid_subdomain=bool(invalid_subdomain), mobile_flow_otp=mobile_flow_otp, is_signup=is_signup, redirect_to=redirect_to) realm = get_realm(subdomain) if realm is None: return redirect_to_subdomain_login_url() return redirect_and_log_into_subdomain(realm, full_name, email_address, is_signup=is_signup, redirect_to=redirect_to) def auth_complete(self, *args: Any, **kwargs: Any) -> Optional[HttpResponse]: """ Returning `None` from this function will redirect the browser to the login page. """ try: # Call the auth_complete method of social_core.backends.oauth.BaseOAuth2 return super().auth_complete(*args, **kwargs) # type: ignore # monkey-patching except AuthFailed: return None except SocialAuthBaseException as e: logging.warning(str(e)) return None class ZulipDummyBackend(ZulipAuthMixin): """ Used when we want to log you in without checking any authentication (i.e. new user registration or when otherwise authentication has already been checked earlier in the process). """ def authenticate(self, username: Optional[str]=None, realm: Optional[Realm]=None, use_dummy_backend: bool=False, return_data: Dict[str, Any]=None) -> Optional[UserProfile]: if use_dummy_backend: # These are kwargs only for readability; they should never be None assert username is not None assert realm is not None return common_get_active_user(username, realm, return_data) return None class EmailAuthBackend(ZulipAuthMixin): """ Email Authentication Backend Allows a user to sign in using an email/password pair rather than a username/password pair. """ def authenticate(self, username: Optional[str]=None, password: Optional[str]=None, realm: Optional[Realm]=None, return_data: Optional[Dict[str, Any]]=None) -> Optional[UserProfile]: """ Authenticate a user based on email address as the user name. """ if username is None or password is None: # Because of how we structure our auth calls to always # specify which backend to use when not using # EmailAuthBackend, username and password should always be set. raise AssertionError("Invalid call to authenticate for EmailAuthBackend") if realm is None: return None if not password_auth_enabled(realm): if return_data is not None: return_data['password_auth_disabled'] = True return None if not email_auth_enabled(realm): if return_data is not None: return_data['email_auth_disabled'] = True return None user_profile = common_get_active_user(username, realm, return_data=return_data) if user_profile is None: return None if user_profile.check_password(password): return user_profile return None class GoogleMobileOauth2Backend(ZulipAuthMixin): """ Google Apps authentication for the legacy Android app. DummyAuthBackend is what's actually used for our modern Google auth, both for web and mobile (the latter via the mobile_flow_otp feature). Allows a user to sign in using a Google-issued OAuth2 token. Ref: https://developers.google.com/+/mobile/android/sign-in#server-side_access_for_your_app https://developers.google.com/accounts/docs/CrossClientAuth#offlineAccess """ def authenticate(self, google_oauth2_token: str=None, realm: Optional[Realm]=None, return_data: Optional[Dict[str, Any]]=None) -> Optional[UserProfile]: if realm is None: return None if return_data is None: return_data = {} if not google_auth_enabled(realm=realm): return_data["google_auth_disabled"] = True return None try: token_payload = googleapiclient.verify_id_token(google_oauth2_token, settings.GOOGLE_CLIENT_ID) except AppIdentityError: return None if token_payload["email_verified"] not in (True, "true"): return_data["valid_attestation"] = False return None return_data["valid_attestation"] = True return common_get_active_user(token_payload["email"], realm, return_data) class ZulipRemoteUserBackend(RemoteUserBackend): create_unknown_user = False def authenticate(self, remote_user: Optional[str], realm: Optional[Realm]=None, return_data: Optional[Dict[str, Any]]=None) -> Optional[UserProfile]: assert remote_user is not None if realm is None: return None if not auth_enabled_helper(["RemoteUser"], realm): return None email = remote_user_to_email(remote_user) return common_get_active_user(email, realm, return_data=return_data) def email_belongs_to_ldap(realm: Realm, email: str) -> bool: if not ldap_auth_enabled(realm): return False # If we don't have an LDAP domain, it's impossible to tell which # accounts are LDAP accounts, so treat all of them as LDAP # accounts if not settings.LDAP_APPEND_DOMAIN: return True # Otherwise, check if the email ends with LDAP_APPEND_DOMAIN return email.strip().lower().endswith("@" + settings.LDAP_APPEND_DOMAIN) class ZulipLDAPException(_LDAPUser.AuthenticationFailed): pass class ZulipLDAPConfigurationError(Exception): pass class ZulipLDAPAuthBackendBase(ZulipAuthMixin, LDAPBackend): # Don't use Django LDAP's permissions functions def has_perm(self, user: Optional[UserProfile], perm: Any, obj: Any=None) -> bool: # Using Any type is safe because we are not doing anything with # the arguments. return False def has_module_perms(self, user: Optional[UserProfile], app_label: Optional[str]) -> bool: return False def get_all_permissions(self, user: Optional[UserProfile], obj: Any=None) -> Set[Any]: # Using Any type is safe because we are not doing anything with # the arguments and always return empty set. return set() def get_group_permissions(self, user: Optional[UserProfile], obj: Any=None) -> Set[Any]: # Using Any type is safe because we are not doing anything with # the arguments and always return empty set. return set() def django_to_ldap_username(self, username: str) -> str: if settings.LDAP_APPEND_DOMAIN: if not username.endswith("@" + settings.LDAP_APPEND_DOMAIN): raise ZulipLDAPException("Username does not match LDAP domain.") return email_to_username(username) return username def ldap_to_django_username(self, username: str) -> str: if settings.LDAP_APPEND_DOMAIN: return "@".join((username, settings.LDAP_APPEND_DOMAIN)) return username class ZulipLDAPAuthBackend(ZulipLDAPAuthBackendBase): REALM_IS_NONE_ERROR = 1 def authenticate(self, username: str, password: str, realm: Optional[Realm]=None, return_data: Optional[Dict[str, Any]]=None) -> Optional[UserProfile]: if realm is None: return None self._realm = realm if not ldap_auth_enabled(realm): return None try: username = self.django_to_ldap_username(username) return ZulipLDAPAuthBackendBase.authenticate(self, username=username, password=password) except ZulipLDAPException: return None # nocoverage # TODO: this may no longer be possible def get_or_build_user(self, username: str, ldap_user: _LDAPUser) -> Tuple[UserProfile, bool]: if settings.LDAP_EMAIL_ATTR is not None: # Get email from ldap attributes. if settings.LDAP_EMAIL_ATTR not in ldap_user.attrs: raise ZulipLDAPException("LDAP user doesn't have the needed %s attribute" % ( settings.LDAP_EMAIL_ATTR,)) username = ldap_user.attrs[settings.LDAP_EMAIL_ATTR][0] return_data = {} # type: Dict[str, Any] user_profile = common_get_active_user(username, self._realm, return_data) if user_profile is not None: # An existing user, successfully authed; return it. return user_profile, False if return_data.get("inactive_realm"): # This happens if there is a user account in a deactivated realm raise ZulipLDAPException("Realm has been deactivated") if return_data.get("inactive_user"): raise ZulipLDAPException("User has been deactivated") if return_data.get("invalid_subdomain"): # TODO: Implement something in the caller for this to # provide a nice user-facing error message for this # situation (right now it just acts like any other auth # failure). raise ZulipLDAPException("Wrong subdomain") if self._realm.deactivated: # This happens if no account exists, but the realm is # deactivated, so we shouldn't create a new user account raise ZulipLDAPException("Realm has been deactivated") # We have valid LDAP credentials; time to create an account. full_name_attr = settings.AUTH_LDAP_USER_ATTR_MAP["full_name"] short_name = full_name = ldap_user.attrs[full_name_attr][0] try: full_name = check_full_name(full_name) except JsonableError as e: raise ZulipLDAPException(e.msg) if "short_name" in settings.AUTH_LDAP_USER_ATTR_MAP: short_name_attr = settings.AUTH_LDAP_USER_ATTR_MAP["short_name"] short_name = ldap_user.attrs[short_name_attr][0] user_profile = do_create_user(username, None, self._realm, full_name, short_name) return user_profile, True # Just like ZulipLDAPAuthBackend, but doesn't let you log in. class ZulipLDAPUserPopulator(ZulipLDAPAuthBackendBase): def authenticate(self, username: str, password: str, realm: Optional[Realm]=None, return_data: Optional[Dict[str, Any]]=None) -> None: return None class DevAuthBackend(ZulipAuthMixin): # Allow logging in as any user without a password. # This is used for convenience when developing Zulip. def authenticate(self, dev_auth_username: Optional[str]=None, realm: Optional[Realm]=None, return_data: Optional[Dict[str, Any]]=None) -> Optional[UserProfile]: assert dev_auth_username is not None if realm is None: return None if not dev_auth_enabled(realm): return None return common_get_active_user(dev_auth_username, realm, return_data=return_data) class GitHubAuthBackend(SocialAuthMixin, GithubOAuth2): auth_backend_name = "GitHub" def get_email_address(self, *args: Any, **kwargs: Any) -> Optional[str]: try: return kwargs['response']['email'] except KeyError: # nocoverage # TODO: investigate return None def get_full_name(self, *args: Any, **kwargs: Any) -> str: # In case of any error return an empty string. Name is used by # the registration page to pre-populate the name field. However, # if it is not supplied, our registration process will make sure # that the user enters a valid name. try: name = kwargs['response']['name'] except KeyError: name = '' if name is None: return '' return name def get_authenticated_user(self, *args: Any, **kwargs: Any) -> Optional[UserProfile]: """ This function is called once the OAuth2 workflow is complete. We override this function to call the proper `do_auth` function depending on whether we are doing individual, team or organization based GitHub authentication. The actual decision on authentication is done in SocialAuthMixin._common_authenticate(). """ user_profile = None team_id = settings.SOCIAL_AUTH_GITHUB_TEAM_ID org_name = settings.SOCIAL_AUTH_GITHUB_ORG_NAME if (team_id is None and org_name is None): try: user_profile = GithubOAuth2.do_auth(self, *args, **kwargs) except AuthFailed: logging.info("User authentication failed.") user_profile = None elif (team_id): backend = GithubTeamOAuth2(self.strategy, self.redirect_uri) try: user_profile = backend.do_auth(*args, **kwargs) except AuthFailed: logging.info("User is not member of GitHub team.") user_profile = None elif (org_name): backend = GithubOrganizationOAuth2(self.strategy, self.redirect_uri) try: user_profile = backend.do_auth(*args, **kwargs) except AuthFailed: logging.info("User is not member of GitHub organization.") user_profile = None return user_profile AUTH_BACKEND_NAME_MAP = { 'Dev': DevAuthBackend, 'Email': EmailAuthBackend, 'GitHub': GitHubAuthBackend, 'Google': GoogleMobileOauth2Backend, 'LDAP': ZulipLDAPAuthBackend, 'RemoteUser': ZulipRemoteUserBackend, } # type: Dict[str, Any]