491 lines
21 KiB
Python
491 lines
21 KiB
Python
# django-mellon - SAML2 authentication for Django
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# Copyright (C) 2014-2019 Entr'ouvert
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as
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# published by the Free Software Foundation, either version 3 of the
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# License, or (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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from __future__ import unicode_literals
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from xml.etree import ElementTree as ET
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import hashlib
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import logging
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import os
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import threading
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import time
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import uuid
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import lasso
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import requests
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import requests.exceptions
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from atomicwrites import atomic_write
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from django.core.exceptions import PermissionDenied, FieldDoesNotExist
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from django.core.files.storage import default_storage
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from django.contrib import auth
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from django.contrib.auth.models import Group
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from django.utils import six
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from django.utils.encoding import force_text
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from django.utils.six.moves.urllib.parse import urlparse
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from . import utils, app_settings, models
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User = auth.get_user_model()
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logger = logging.getLogger(__name__)
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class UserCreationError(Exception):
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pass
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def display_truncated_list(l, max_length=10):
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s = '[' + ', '.join(map(six.text_type, l))
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if len(l) > max_length:
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s += '..truncated more than %d items (%d)]' % (max_length, len(l))
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else:
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s += ']'
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return s
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class DefaultAdapter(object):
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def get_idp(self, entity_id):
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'''Find the first IdP definition matching entity_id'''
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for idp in self.get_idps():
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if entity_id == idp['ENTITY_ID']:
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return idp
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def get_identity_providers_setting(self):
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return app_settings.IDENTITY_PROVIDERS
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def get_users_queryset(self, idp, saml_attributes):
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return User.objects.all()
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def get_idps(self):
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for i, idp in enumerate(self.get_identity_providers_setting()):
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if self.load_idp(idp, i):
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yield idp
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def load_metadata_path(self, idp, i):
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path = idp['METADATA_PATH']
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if not os.path.exists(path):
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logger.warning('metadata path %s does not exist', path)
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return
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last_update = idp.get('METADATA_PATH_LAST_UPDATE', 0)
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try:
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mtime = os.stat(path).st_mtime
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except OSError as e:
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logger.warning('metadata path %s : stat() call failed, %s', path, e)
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return
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if last_update == 0 or mtime >= last_update:
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idp['METADATA_PATH_LAST_UPDATE'] = time.time()
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try:
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with open(path) as fd:
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metadata = fd.read()
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except OSError as e:
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logger.warning('metadata path %s : open()/read() call failed, %s', path, e)
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return
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entity_id = self.load_entity_id(metadata, i)
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if not entity_id:
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logger.error('invalid metadata file retrieved from %s', path)
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return
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if 'ENTITY_ID' in idp and idp['ENTITY_ID'] != entity_id:
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logger.error('metadata path %s : entityID changed %r != %r', path, entity_id, idp['ENTITY_ID'])
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del idp['ENTITY_ID']
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idp['METADATA'] = metadata
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def load_metadata_url(self, idp, i):
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url = idp['METADATA_URL']
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metadata_cache_time = utils.get_setting(idp, 'METADATA_CACHE_TIME')
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timeout = utils.get_setting(idp, 'METADATA_HTTP_TIMEOUT')
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warning = logger.warning
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if 'METADATA' not in idp:
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# if we have no metadata in cache, we must emit errors
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warning = logger.error
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try:
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hostname = urlparse(url).hostname
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except (ValueError, TypeError) as e:
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warning('invalid METADATA_URL %r: %s', url, e)
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return
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if not hostname:
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warning('no hostname in METADATA_URL %r: %s', url)
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return
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last_update = idp.get('METADATA_URL_LAST_UPDATE', 0)
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now = time.time()
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try:
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url_fingerprint = hashlib.md5(url.encode('ascii')).hexdigest()
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file_cache_key = '%s_%s.xml' % (hostname, url_fingerprint)
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except (UnicodeError, TypeError, ValueError):
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warning('unable to compute file_cache_key')
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return
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cache_directory = default_storage.path('mellon_metadata_cache')
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file_cache_path = os.path.join(cache_directory, file_cache_key)
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if metadata_cache_time:
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# METADATA_CACHE_TIME == 0 disable the file cache
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if not os.path.exists(cache_directory):
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os.makedirs(cache_directory)
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if os.path.exists(file_cache_path) and 'METADATA' not in idp:
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try:
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with open(file_cache_path) as fd:
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idp['METADATA'] = fd.read()
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# use file cache mtime as last_update time, prevent too many loading from different workers
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last_update = max(last_update, os.stat(file_cache_path).st_mtime)
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except (IOError, OSError):
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warning('metadata url %s : error when loading the file cache %s', url, file_cache_path)
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# fresh cache, skip loading
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if last_update and 'METADATA' in idp and (now - last_update) < metadata_cache_time:
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return
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def __http_get():
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try:
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verify_ssl_certificate = utils.get_setting(
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idp, 'VERIFY_SSL_CERTIFICATE')
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try:
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response = requests.get(url, verify=verify_ssl_certificate, timeout=timeout)
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response.raise_for_status()
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except requests.exceptions.RequestException as e:
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warning('metadata url %s : HTTP request failed %s', url, e)
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return
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entity_id = self.load_entity_id(response.text, i)
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if not entity_id:
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warning('invalid metadata file retrieved from %s', url)
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return
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if 'ENTITY_ID' in idp and idp['ENTITY_ID'] != entity_id:
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# entityID change is always en error
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logger.error('metadata url %s : entityID changed %r != %r', url, entity_id, idp['ENTITY_ID'])
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del idp['ENTITY_ID']
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idp['METADATA'] = response.text
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idp['METADATA_URL_LAST_UPDATE'] = now
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if metadata_cache_time:
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try:
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with atomic_write(file_cache_path, mode='wb', overwrite=True) as fd:
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fd.write(response.text.encode('utf-8'))
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except OSError as e:
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logger.error('metadata url %s : could not write file cache %s, %s', url, file_cache_path, e)
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idp['METADATA_PATH'] = file_cache_path
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# prevent reloading of the file cache immediately
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idp['METADATA_PATH_LAST_UPDATE'] = time.time() + 1
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logger.debug('metadata url %s : update throught HTTP', url)
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finally:
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# release thread object
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idp.pop('METADATA_URL_UPDATE_THREAD', None)
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# emit an error if cache is too old
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if metadata_cache_time:
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stale_timeout = 24 * metadata_cache_time
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if last_update and (now - idp['METADATA_URL_LAST_UPDATE']) > stale_timeout:
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logger.error('metadata url %s: not updated since %.1f hours',
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url, stale_timeout / 3600.0)
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# we have cache, update in background
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if last_update and 'METADATA' in idp:
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t = threading.Thread(target=__http_get)
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t.start()
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# store thread in idp for tests
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idp['METADATA_URL_UPDATE_THREAD'] = t
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# suspend updates for HTTP timeout + 5 seconds
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idp['METADATA_URL_LAST_UPDATE'] = last_update + timeout + 5
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else:
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# synchronous update
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__http_get()
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def load_metadata(self, idp, i):
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# legacy support
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if 'METADATA' in idp and idp['METADATA'].startswith('/'):
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idp['METADATA_PATH'] = idp['METADATA']
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del idp['METADATA']
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if 'METADATA_PATH' in idp:
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self.load_metadata_path(idp, i)
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if 'METADATA_URL' in idp:
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self.load_metadata_url(idp, i)
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if 'METADATA' in idp:
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if 'ENTITY_ID' not in idp:
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entity_id = self.load_entity_id(idp['METADATA'], i)
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if entity_id:
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idp['ENTITY_ID'] = entity_id
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if 'ENTITY_ID' in idp:
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return idp['METADATA']
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def load_entity_id(self, metadata, i):
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try:
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doc = ET.fromstring(metadata)
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except (TypeError, ET.ParseError):
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logger.error('METADATA of %d-th idp is invalid', i)
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return None
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if doc.tag != '{%s}EntityDescriptor' % lasso.SAML2_METADATA_HREF:
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logger.error('METADATA of %d-th idp has no EntityDescriptor root tag', i)
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return None
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if 'entityID' not in doc.attrib:
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logger.error(
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'METADATA of %d-th idp has no entityID attribute on its root tag', i)
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return None
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return doc.attrib['entityID']
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def load_idp(self, idp, i):
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self.load_metadata(idp, i)
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return 'ENTITY_ID' in idp
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def authorize(self, idp, saml_attributes):
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if not idp:
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return False
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required_classref = utils.get_setting(idp, 'AUTHN_CLASSREF')
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if required_classref:
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given_classref = saml_attributes['authn_context_class_ref']
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if given_classref is None or \
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given_classref not in required_classref:
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raise PermissionDenied
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return True
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def format_username(self, idp, saml_attributes):
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realm = utils.get_setting(idp, 'REALM')
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username_template = utils.get_setting(idp, 'USERNAME_TEMPLATE')
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try:
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username = force_text(username_template).format(
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realm=realm, attributes=saml_attributes, idp=idp)[:30]
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except ValueError:
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logger.error('invalid username template %r', username_template)
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except (AttributeError, KeyError, IndexError) as e:
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logger.error(
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'invalid reference in username template %r: %s', username_template, e)
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except Exception:
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logger.exception('unknown error when formatting username')
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else:
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return username
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def create_user(self, user_class):
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return user_class.objects.create(username=uuid.uuid4().hex[:30])
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def finish_create_user(self, idp, saml_attributes, user):
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username = self.format_username(idp, saml_attributes)
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if not username:
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logger.warning('could not build a username, login refused')
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raise UserCreationError
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user.username = username
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user.save()
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def lookup_user(self, idp, saml_attributes):
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transient_federation_attribute = utils.get_setting(idp, 'TRANSIENT_FEDERATION_ATTRIBUTE')
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if saml_attributes['name_id_format'] == lasso.SAML2_NAME_IDENTIFIER_FORMAT_TRANSIENT:
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if (transient_federation_attribute
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and saml_attributes.get(transient_federation_attribute)):
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name_id = saml_attributes[transient_federation_attribute]
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if not isinstance(name_id, six.string_types):
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if len(name_id) == 1:
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name_id = name_id[0]
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else:
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logger.warning('more than one value for attribute %r, cannot federate',
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transient_federation_attribute)
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return None
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else:
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return None
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else:
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name_id = saml_attributes['name_id_content']
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issuer = saml_attributes['issuer']
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try:
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user = self.get_users_queryset(idp, saml_attributes).get(
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saml_identifiers__name_id=name_id,
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saml_identifiers__issuer=issuer)
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logger.info('looked up user %s with name_id %s from issuer %s', user, name_id, issuer)
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return user
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except User.DoesNotExist:
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pass
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user = None
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lookup_by_attributes = utils.get_setting(idp, 'LOOKUP_BY_ATTRIBUTES')
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if lookup_by_attributes:
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user = self._lookup_by_attributes(idp, saml_attributes, lookup_by_attributes)
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created = False
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if not user:
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if not utils.get_setting(idp, 'PROVISION'):
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logger.debug('provisionning disabled, login refused')
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return None
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created = True
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user = self.create_user(User)
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nameid_user = self._link_user(idp, saml_attributes, issuer, name_id, user)
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if user != nameid_user:
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logger.info('looked up user %s with name_id %s from issuer %s', nameid_user, name_id, issuer)
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if created:
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user.delete()
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return nameid_user
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if created:
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try:
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self.finish_create_user(idp, saml_attributes, nameid_user)
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except UserCreationError:
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user.delete()
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return None
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logger.info('created new user %s with name_id %s from issuer %s', nameid_user, name_id, issuer)
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return nameid_user
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def _lookup_by_attributes(self, idp, saml_attributes, lookup_by_attributes):
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if not isinstance(lookup_by_attributes, list):
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logger.error('invalid LOOKUP_BY_ATTRIBUTES configuration %r: it must be a list', lookup_by_attributes)
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return None
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users = set()
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for line in lookup_by_attributes:
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if not isinstance(line, dict):
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logger.error('invalid LOOKUP_BY_ATTRIBUTES configuration %r: it must be a list of dicts', line)
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continue
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user_field = line.get('user_field')
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if not hasattr(user_field, 'isalpha'):
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logger.error('invalid LOOKUP_BY_ATTRIBUTES configuration %r: user_field is missing', line)
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continue
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try:
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User._meta.get_field(user_field)
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except FieldDoesNotExist:
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logger.error('invalid LOOKUP_BY_ATTRIBUTES configuration %r, user field %s does not exist',
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line, user_field)
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continue
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saml_attribute = line.get('saml_attribute')
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if not hasattr(saml_attribute, 'isalpha'):
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logger.error('invalid LOOKUP_BY_ATTRIBUTES configuration %r: saml_attribute is missing', line)
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continue
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values = saml_attributes.get(saml_attribute)
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if not values:
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logger.warning('looking for user by saml attribute %r and user field %r, skipping because empty',
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saml_attribute, user_field)
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continue
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ignore_case = line.get('ignore-case', False)
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for value in values:
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key = user_field
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if ignore_case:
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key += '__iexact'
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users_found = self.get_users_queryset(idp, saml_attributes).filter(
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saml_identifiers__isnull=True, **{key: value})
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if not users_found:
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logger.debug('looking for users by attribute %r and user field %r with value %r: not found',
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saml_attribute, user_field, value)
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continue
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logger.info('looking for user by attribute %r and user field %r with value %r: found %s',
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saml_attribute, user_field, value, display_truncated_list(users_found))
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users.update(users_found)
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if len(users) == 1:
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user = list(users)[0]
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logger.info('looking for user by attributes %r: found user %s', lookup_by_attributes, user)
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return user
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elif len(users) > 1:
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logger.warning('looking for user by attributes %r: too many users found(%d), failing',
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lookup_by_attributes, len(users))
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return None
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def _link_user(self, idp, saml_attributes, issuer, name_id, user):
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saml_id, created = models.UserSAMLIdentifier.objects.get_or_create(
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name_id=name_id, issuer=issuer, defaults={'user': user})
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if created:
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return user
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else:
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return saml_id.user
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def provision(self, user, idp, saml_attributes):
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self.provision_attribute(user, idp, saml_attributes)
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self.provision_superuser(user, idp, saml_attributes)
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self.provision_groups(user, idp, saml_attributes)
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def provision_attribute(self, user, idp, saml_attributes):
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realm = utils.get_setting(idp, 'REALM')
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attribute_mapping = utils.get_setting(idp, 'ATTRIBUTE_MAPPING')
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attribute_set = False
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for field, tpl in attribute_mapping.items():
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try:
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value = force_text(tpl).format(realm=realm, attributes=saml_attributes, idp=idp)
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except ValueError:
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logger.warning('invalid attribute mapping template %r', tpl)
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except (AttributeError, KeyError, IndexError, ValueError) as e:
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logger.warning(
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'invalid reference in attribute mapping template %r: %s', tpl, e)
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else:
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model_field = user._meta.get_field(field)
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if hasattr(model_field, 'max_length'):
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value = value[:model_field.max_length]
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if getattr(user, field) != value:
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old_value = getattr(user, field)
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setattr(user, field, value)
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attribute_set = True
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logger.info('set field %s of user %s to value %r (old value %r)', field, user, value, old_value)
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if attribute_set:
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user.save()
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def provision_superuser(self, user, idp, saml_attributes):
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superuser_mapping = utils.get_setting(idp, 'SUPERUSER_MAPPING')
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if not superuser_mapping:
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return
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attribute_set = False
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for key, values in superuser_mapping.items():
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if key in saml_attributes:
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if not isinstance(values, (tuple, list)):
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values = [values]
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values = set(values)
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attribute_values = saml_attributes[key]
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if not isinstance(attribute_values, (tuple, list)):
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attribute_values = [attribute_values]
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attribute_values = set(attribute_values)
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if attribute_values & values:
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if not (user.is_staff and user.is_superuser):
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user.is_staff = True
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user.is_superuser = True
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attribute_set = True
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logger.info('flag is_staff and is_superuser added to user %s', user)
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break
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else:
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if user.is_superuser or user.is_staff:
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user.is_staff = False
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user.is_superuser = False
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logger.info('flag is_staff and is_superuser removed from user %s', user)
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attribute_set = True
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if attribute_set:
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user.save()
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def provision_groups(self, user, idp, saml_attributes):
|
|
group_attribute = utils.get_setting(idp, 'GROUP_ATTRIBUTE')
|
|
create_group = utils.get_setting(idp, 'CREATE_GROUP')
|
|
if group_attribute in saml_attributes:
|
|
values = saml_attributes[group_attribute]
|
|
if not isinstance(values, (list, tuple)):
|
|
values = [values]
|
|
groups = []
|
|
for value in set(values):
|
|
if create_group:
|
|
group, created = Group.objects.get_or_create(name=value)
|
|
else:
|
|
try:
|
|
group = Group.objects.get(name=value)
|
|
except Group.DoesNotExist:
|
|
continue
|
|
groups.append(group)
|
|
for group in Group.objects.filter(pk__in=[g.pk for g in groups]).exclude(user=user):
|
|
logger.info(
|
|
'adding group %s (%s) to user %s (%s)', group, group.pk, user, user.pk)
|
|
User.groups.through.objects.get_or_create(group=group, user=user)
|
|
qs = User.groups.through.objects.exclude(
|
|
group__pk__in=[g.pk for g in groups]).filter(user=user)
|
|
for rel in qs:
|
|
logger.info('removing group %s (%s) from user %s (%s)', rel.group, rel.group.pk, rel.user, rel.user.pk)
|
|
qs.delete()
|