django-mellon/mellon/views.py

554 lines
25 KiB
Python

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 = (
'<eo:next_url xmlns:eo="https://www.entrouvert.com/">%s</eo:next_url>' % eo_next_url,)
else:
authn_request.extensions.setOriginalXmlnode(
'''<samlp:Extensions
xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
xmlns:eo="https://www.entrouvert.com/">
<eo:next_url>%s</eo:next_url>
</samlp:Extensions>''' % 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')