import logging import requests import lasso import uuid from requests.exceptions import RequestException from xml.sax.saxutils import escape import xml.etree.ElementTree as ET from django.core.urlresolvers import reverse from django.views.generic import View from django.http import HttpResponseBadRequest, HttpResponseRedirect, HttpResponse from django.contrib import auth from django.conf import settings from django.views.decorators.csrf import csrf_exempt from django.shortcuts import render, resolve_url from django.utils.http import urlencode from django.utils import six from django.utils.encoding import force_text from django.contrib.auth import REDIRECT_FIELD_NAME from django.db import transaction from django.utils.translation import ugettext as _ from . import app_settings, utils RETRY_LOGIN_COOKIE = 'MELLON_RETRY_LOGIN' lasso.setFlag('thin-sessions') if six.PY3: def lasso_decode(x): return x else: def lasso_decode(x): return x.decode('utf-8') EO_NS = 'https://www.entrouvert.com/' LOGIN_HINT = '{%s}login-hint' % EO_NS class LogMixin(object): """Initialize a module logger in new objects""" def __init__(self, *args, **kwargs): self.log = logging.getLogger(__name__) super(LogMixin, self).__init__(*args, **kwargs) def check_next_url(request, next_url): log = logging.getLogger(__name__) if not next_url: return if not utils.is_nonnull(next_url): log.warning('next parameter ignored, as it contains null characters') return try: next_url.encode('ascii') except UnicodeDecodeError: log.warning('next parameter ignored, as is\'s not an ASCII string') return if not utils.same_origin(next_url, request.build_absolute_uri()): log.warning('next parameter ignored as it is not of the same origin') return return next_url class ProfileMixin(object): profile = None def set_next_url(self, next_url): if not check_next_url(self.request, next_url): return self.set_state('next_url', next_url) def set_state(self, name, value): assert self.profile relay_state = self.get_relay_state(create=True) self.request.session['mellon_%s_%s' % (name, relay_state)] = value def get_state(self, name, default=None): if self.profile: relay_state = self.get_relay_state() key = 'mellon_%s_%s' % (name, relay_state) return self.request.session.get(key, default) return default def get_relay_state(self, create=False): if self.profile and self.profile.msgRelayState: try: return uuid.UUID(self.profile.msgRelayState) except ValueError: pass if create: assert self.profile self.profile.msgRelayState = str(uuid.uuid4()) return self.profile.msgRelayState def get_next_url(self, default=None): return self.get_state('next_url', default=default) def show_message_status_is_not_success(self, profile, prefix): status_codes, idp_message = utils.get_status_codes_and_message(profile) args = [u'%s: status is not success codes: %r', prefix, status_codes] if idp_message: args[0] += u' message: %s' args.append(idp_message) self.log.warning(*args) class LoginView(ProfileMixin, LogMixin, View): def get_idp(self, request): entity_id = request.POST.get('entityID') or request.GET.get('entityID') if not entity_id: for idp in utils.get_idps(): return idp else: return None else: return utils.get_idp(entity_id) def post(self, request, *args, **kwargs): '''Assertion consumer''' if 'SAMLart' in request.POST: return self.continue_sso_artifact(request, lasso.HTTP_METHOD_ARTIFACT_POST) if 'SAMLResponse' not in request.POST: return self.get(request, *args, **kwargs) if not utils.is_nonnull(request.POST['SAMLResponse']): return HttpResponseBadRequest('SAMLResponse contains a null character') self.log.info('Got SAML Response', extra={'saml_response': request.POST['SAMLResponse']}) self.profile = login = utils.create_login(request) idp_message = None status_codes = [] # prevent null characters in SAMLResponse try: login.processAuthnResponseMsg(request.POST['SAMLResponse']) login.acceptSso() except lasso.ProfileCannotVerifySignatureError: self.log.warning('SAML authentication failed: signature validation failed for %r', login.remoteProviderId) except lasso.ParamError: self.log.exception('lasso param error') except (lasso.LoginStatusNotSuccessError, lasso.ProfileStatusNotSuccessError, lasso.ProfileRequestDeniedError): self.show_message_status_is_not_success(login, 'SAML authentication failed') except lasso.Error as e: return HttpResponseBadRequest('error processing the authentication response: %r' % e) else: if 'RelayState' in request.POST and utils.is_nonnull(request.POST['RelayState']): login.msgRelayState = request.POST['RelayState'] return self.sso_success(request, login) return self.sso_failure(request, reason=idp_message, status_codes=status_codes) def sso_failure(self, request, reason='', status_codes=()): '''show error message to user after a login failure''' login = self.profile idp = utils.get_idp(login.remoteProviderId) error_url = utils.get_setting(idp, 'ERROR_URL') error_redirect_after_timeout = utils.get_setting(idp, 'ERROR_REDIRECT_AFTER_TIMEOUT') if error_url: error_url = resolve_url(error_url) next_url = error_url or self.get_next_url(default=resolve_url(settings.LOGIN_REDIRECT_URL)) return render(request, 'mellon/authentication_failed.html', { 'debug': settings.DEBUG, 'reason': reason, 'status_codes': status_codes, 'issuer': login.remoteProviderId, 'next_url': next_url, 'relaystate': login.msgRelayState, 'error_redirect_after_timeout': error_redirect_after_timeout, }) def sso_success(self, request, login): attributes = {} attribute_statements = login.assertion.attributeStatement for ats in attribute_statements: for at in ats.attribute: values = attributes.setdefault(at.name, []) for value in at.attributeValue: content = [any.exportToXml() for any in value.any] content = ''.join(content) values.append(lasso_decode(content)) attributes['issuer'] = login.remoteProviderId if login.nameIdentifier: name_id = login.nameIdentifier name_id_format = force_text(name_id.format or lasso.SAML2_NAME_IDENTIFIER_FORMAT_UNSPECIFIED) attributes.update({ 'name_id_content': lasso_decode(name_id.content), 'name_id_format': name_id_format }) if name_id.nameQualifier: attributes['name_id_name_qualifier'] = force_text(name_id.nameQualifier) if name_id.spNameQualifier: attributes['name_id_sp_name_qualifier'] = force_text(name_id.spNameQualifier) authn_statement = login.assertion.authnStatement[0] if authn_statement.authnInstant: attributes['authn_instant'] = utils.iso8601_to_datetime(authn_statement.authnInstant) if authn_statement.sessionNotOnOrAfter: attributes['session_not_on_or_after'] = utils.iso8601_to_datetime( authn_statement.sessionNotOnOrAfter) if authn_statement.sessionIndex: attributes['session_index'] = authn_statement.sessionIndex attributes['authn_context_class_ref'] = () if authn_statement.authnContext: authn_context = authn_statement.authnContext if authn_context.authnContextClassRef: attributes['authn_context_class_ref'] = \ authn_context.authnContextClassRef self.log.debug('trying to authenticate with attributes %r', attributes) response = self.authenticate(request, login, attributes) response.delete_cookie(RETRY_LOGIN_COOKIE) return response def authenticate(self, request, login, attributes): user = auth.authenticate(saml_attributes=attributes) next_url = self.get_next_url(default=resolve_url(settings.LOGIN_REDIRECT_URL)) if user is not None: if user.is_active: utils.login(request, user) self.log.info('user %s (NameID is %r) logged in using SAML', user, attributes['name_id_content']) request.session['mellon_session'] = utils.flatten_datetime(attributes) if ('session_not_on_or_after' in attributes and not settings.SESSION_EXPIRE_AT_BROWSER_CLOSE): request.session.set_expiry( utils.get_seconds_expiry( attributes['session_not_on_or_after'])) else: self.log.warning('user %s (NameID is %r) is inactive, login refused', user, attributes['name_id_content']) return render(request, 'mellon/inactive_user.html', { 'user': user, 'saml_attributes': attributes}) else: self.log.warning('no user found for NameID %r', attributes['name_id_content']) return render(request, 'mellon/user_not_found.html', {'saml_attributes': attributes}) request.session['lasso_session_dump'] = login.session.dump() return HttpResponseRedirect(next_url) def retry_login(self): '''Retry login if it failed for a temporary error. Use a cookie to prevent looping forever. ''' if RETRY_LOGIN_COOKIE in self.request.COOKIES: response = self.sso_failure( self.request, reason=_('There were too many redirections with the identity provider.')) response.delete_cookie(RETRY_LOGIN_COOKIE) return response url = reverse('mellon_login') next_url = self.get_next_url() if next_url: url = '%s?%s' % (url, urlencode({REDIRECT_FIELD_NAME: next_url})) response = HttpResponseRedirect(url) response.set_cookie(RETRY_LOGIN_COOKIE, value='1', max_age=None) return response def continue_sso_artifact(self, request, method): idp_message = None status_codes = [] if method == lasso.HTTP_METHOD_ARTIFACT_GET: message = request.META['QUERY_STRING'] artifact = request.GET['SAMLart'] relay_state = request.GET.get('RelayState') else: # method == lasso.HTTP_METHOD_ARTIFACT_POST: message = request.POST['SAMLart'] artifact = request.POST['SAMLart'] relay_state = request.POST.get('RelayState') self.profile = login = utils.create_login(request) if relay_state and utils.is_nonnull(relay_state): login.msgRelayState = relay_state try: login.initRequest(message, method) except lasso.ProfileInvalidArtifactError: self.log.warning(u'artifact is malformed %r', artifact) return HttpResponseBadRequest(u'artifact is malformed %r' % artifact) except lasso.ServerProviderNotFoundError: self.log.warning('no entity id found for artifact %s', artifact) return HttpResponseBadRequest( 'no entity id found for this artifact %r' % artifact) idp = utils.get_idp(login.remoteProviderId) if not idp: self.log.warning('entity id %r is unknown', login.remoteProviderId) return HttpResponseBadRequest( 'entity id %r is unknown' % login.remoteProviderId) verify_ssl_certificate = utils.get_setting( idp, 'VERIFY_SSL_CERTIFICATE') login.buildRequestMsg() try: result = requests.post(login.msgUrl, data=login.msgBody, headers={'content-type': 'text/xml'}, timeout=app_settings.ARTIFACT_RESOLVE_TIMEOUT, verify=verify_ssl_certificate) except RequestException as e: self.log.warning('unable to reach %r: %s', login.msgUrl, e) return self.sso_failure(request, reason=_('IdP is temporarily down, please try again ' 'later.'), status_codes=status_codes) if result.status_code != 200: self.log.warning('SAML authentication failed: IdP returned %s when given artifact: %r', result.status_code, result.content) return self.sso_failure(request, reason=idp_message, status_codes=status_codes) self.log.info('Got SAML Artifact Response', extra={'saml_response': result.content}) result.encoding = utils.get_xml_encoding(result.content) try: login.processResponseMsg(result.text) login.acceptSso() except lasso.ProfileMissingResponseError: # artifact is invalid, idp returned no response self.log.warning('ArtifactResolveResponse is empty: dead artifact %r', artifact) return self.retry_login() except lasso.ProfileInvalidMsgError: self.log.warning('ArtifactResolveResponse is malformed %r', result.content[:200]) if settings.DEBUG: return HttpResponseBadRequest('ArtififactResolveResponse is malformed\n%r' % result.content) else: return HttpResponseBadRequest('ArtififactResolveResponse is malformed') except lasso.ProfileCannotVerifySignatureError: self.log.warning('SAML authentication failed: signature validation failed for %r', login.remoteProviderId) except lasso.ParamError: self.log.exception('lasso param error') except (lasso.LoginStatusNotSuccessError, lasso.ProfileStatusNotSuccessError, lasso.ProfileRequestDeniedError): status = login.response.status a = status while a.statusCode: status_codes.append(a.statusCode.value) a = a.statusCode args = ['SAML authentication failed: status is not success codes: %r', status_codes] if status.statusMessage: idp_message = lasso_decode(status.statusMessage) args[0] += ' message: %r' args.append(status.statusMessage) self.log.warning(*args) except lasso.Error as e: self.log.exception('unexpected lasso error') return HttpResponseBadRequest('error processing the authentication response: %r' % e) else: return self.sso_success(request, login) return self.sso_failure(request, reason=idp_message, status_codes=status_codes) def request_discovery_service(self, request, is_passive=False): return_url = request.build_absolute_uri() return_url += '&' if '?' in return_url else '?' return_url += 'nodisco=1' url = app_settings.DISCOVERY_SERVICE_URL params = { # prevent redirect loops with the discovery service 'entityID': request.build_absolute_uri(reverse('mellon_metadata')), 'return': return_url, } if is_passive: params['isPassive'] = 'true' url += '?' + urlencode(params) return HttpResponseRedirect(url) def get(self, request, *args, **kwargs): '''Initialize login request''' if 'SAMLart' in request.GET: return self.continue_sso_artifact(request, lasso.HTTP_METHOD_ARTIFACT_GET) # redirect to discovery service if needed if ('entityID' not in request.GET and 'nodisco' not in request.GET and app_settings.DISCOVERY_SERVICE_URL): return self.request_discovery_service( request, is_passive=request.GET.get('passive') == '1') next_url = check_next_url(self.request, request.GET.get(REDIRECT_FIELD_NAME)) idp = self.get_idp(request) if idp is None: return HttpResponseBadRequest('no idp found') self.profile = login = utils.create_login(request) self.log.debug('authenticating to %r', idp['ENTITY_ID']) try: login.initAuthnRequest(idp['ENTITY_ID'], lasso.HTTP_METHOD_REDIRECT) authn_request = login.request # configure NameID policy policy = authn_request.nameIdPolicy policy.allowCreate = utils.get_setting(idp, 'NAME_ID_POLICY_ALLOW_CREATE') policy.format = utils.get_setting(idp, 'NAME_ID_POLICY_FORMAT') force_authn = utils.get_setting(idp, 'FORCE_AUTHN') if force_authn: authn_request.forceAuthn = True if request.GET.get('passive') == '1': authn_request.isPassive = True # configure requested AuthnClassRef authn_classref = utils.get_setting(idp, 'AUTHN_CLASSREF') if authn_classref: authn_classref = tuple([str(x) for x in authn_classref]) req_authncontext = lasso.Samlp2RequestedAuthnContext() authn_request.requestedAuthnContext = req_authncontext req_authncontext.authnContextClassRef = authn_classref if utils.get_setting(idp, 'ADD_AUTHNREQUEST_NEXT_URL_EXTENSION'): authn_request.extensions = lasso.Samlp2Extensions() eo_next_url = escape(request.build_absolute_uri(next_url or '/')) # lasso>2.5.1 introduced a better API if hasattr(authn_request.extensions, 'any'): authn_request.extensions.any = ( '%s' % eo_next_url,) else: authn_request.extensions.setOriginalXmlnode( ''' %s ''' % eo_next_url ) self.set_next_url(next_url) self.add_login_hints(idp, authn_request, request=request, next_url=next_url) login.buildAuthnRequestMsg() except lasso.Error as e: return HttpResponseBadRequest('error initializing the authentication request: %r' % e) self.log.debug('sending authn request %r', authn_request.dump()) self.log.debug('to url %r', login.msgUrl) return HttpResponseRedirect(login.msgUrl) def add_extension_node(self, authn_request, node): '''Factorize adding an XML node to the samlp:Extensions node''' if not authn_request.extensions: authn_request.extensions = lasso.Samlp2Extensions() assert hasattr(authn_request.extensions, 'any'), 'extension nodes need lasso > 2.5.1' serialized = ET.tostring(node, 'utf-8') # tostring return bytes in PY3, but lasso needs str if six.PY3: serialized = serialized.decode('utf-8') extension_content = authn_request.extensions.any or () extension_content += (serialized,) authn_request.extensions.any = extension_content def is_in_backoffice(self, request, next_url): path = utils.get_local_path(request, next_url) return path.startswith(('/admin/', '/manage/', '/manager/')) def add_login_hints(self, idp, authn_request, request, next_url=None): login_hints = utils.get_setting(idp, 'LOGIN_HINTS', []) hints = [] for login_hint in login_hints: if login_hint == 'backoffice': if self.is_in_backoffice(request, next_url): hints.append('backoffice') if login_hint == 'always_backoffice': hints.append('backoffice') for hint in hints: node = ET.Element(LOGIN_HINT) node.text = hint self.add_extension_node(authn_request, node) # we need fine control of transactions to prevent double user creations login = transaction.non_atomic_requests(csrf_exempt(LoginView.as_view())) class LogoutView(ProfileMixin, LogMixin, View): def get(self, request): if 'SAMLRequest' in request.GET: return self.idp_logout(request) elif 'SAMLResponse' in request.GET: return self.sp_logout_response(request) else: return self.sp_logout_request(request) def idp_logout(self, request): '''Handle logout request emitted by the IdP''' self.profile = logout = utils.create_logout(request) try: logout.processRequestMsg(request.META['QUERY_STRING']) except lasso.Error as e: return HttpResponseBadRequest('error processing logout request: %r' % e) try: logout.validateRequest() except lasso.Error as e: self.log.warning('error validating logout request: %r' % e) issuer = request.session.get('mellon_session', {}).get('issuer') if issuer == logout.remoteProviderId: self.log.info(u'user logged out by IdP SLO request') auth.logout(request) try: logout.buildResponseMsg() except lasso.Error as e: return HttpResponseBadRequest('error processing logout request: %r' % e) return HttpResponseRedirect(logout.msgUrl) def sp_logout_request(self, request): '''Launch a logout request to the identity provider''' next_url = request.GET.get(REDIRECT_FIELD_NAME) referer = request.META.get('HTTP_REFERER') if not referer or utils.same_origin(referer, request.build_absolute_uri()): if request.user.is_authenticated(): logout = None try: issuer = request.session.get('mellon_session', {}).get('issuer') if issuer: self.profile = logout = utils.create_logout(request) try: if 'lasso_session_dump' in request.session: logout.setSessionFromDump(request.session['lasso_session_dump']) else: self.log.error('unable to find lasso session dump') logout.initRequest(issuer, lasso.HTTP_METHOD_REDIRECT) logout.buildRequestMsg() except lasso.Error as e: self.log.error('unable to initiate a logout request %r', e) else: self.log.debug('sending LogoutRequest %r', logout.request.dump()) self.log.debug('to URL %r', logout.msgUrl) return HttpResponseRedirect(logout.msgUrl) finally: auth.logout(request) # set next_url after local logout, as the session is wiped by auth.logout if logout: self.set_next_url(next_url) self.log.info(u'user logged out, SLO request sent to IdP') else: self.log.warning('logout refused referer %r is not of the same origin', referer) return HttpResponseRedirect(next_url) def sp_logout_response(self, request): '''Launch a logout request to the identity provider''' self.profile = logout = utils.create_logout(request) # the user shouldn't be logged anymore at this point but it may happen # that a concurrent SSO happened in the meantime, so we do another # logout to make sure. auth.logout(request) try: logout.processResponseMsg(request.META['QUERY_STRING']) except lasso.ProfileStatusNotSuccessError: self.show_message_status_is_not_success(logout, 'SAML logout failed') except lasso.LogoutPartialLogoutError: self.log.warning('partial logout') except lasso.Error as e: self.log.warning('unable to process a logout response: %s', e) return HttpResponseRedirect(resolve_url(settings.LOGIN_REDIRECT_URL)) next_url = self.get_next_url(default=resolve_url(settings.LOGIN_REDIRECT_URL)) return HttpResponseRedirect(next_url) logout = LogoutView.as_view() def metadata(request): metadata = utils.create_metadata(request) return HttpResponse(metadata, content_type='text/xml')