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external_authentication_ldap.py
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Tue, Nov 5, 04:50

external_authentication_ldap.py
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# -*- coding: utf-8 -*-
##
## $Id$
##
## This file is part of CDS Invenio.
## Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007 CERN.
##
## CDS Invenio is free software; you can redistribute it and/or
## modify it under the terms of the GNU General Public License as
## published by the Free Software Foundation; either version 2 of the
## License, or (at your option) any later version.
##
## CDS Invenio is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with CDS Invenio; if not, write to the Free Software Foundation, Inc.,
## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
"""External user authentication for EPFL's LDAP instance.
This LDAP external authentication system relies on a collaborative LDAP
organized like this:
o=EPFL, c=CH
|
|
+--ou=groups
| |
| |
| +--- cn=xxx
| displayName= name of the group
| uniqueIdentifier= some local id for groups
|
|
|
+--ou=users
| |
| |
| +---uid= some local id for users (ex: grfavre)
| uniqueIdentifier= another local id (ex: 128933)
| mail=xxx@xxx.xx
| memberOf= id of a group
| memberOf= id of another group
|
+
This example of an LDAP authentication should help you develop yours in your
specific installation.
"""
__revision__ = \
"$Id$"
import ldap
from invenio.external_authentication import ExternalAuth, \
InvenioWebAccessExternalAuthError
CFG_EXTERNAL_AUTH_LDAP_SERVERS = ['ldap://scoldap.epfl.ch']
CFG_EXTERNAL_AUTH_LDAP_CONTEXT = "o=EPFL,c=CH"
CFG_EXTERNAL_AUTH_LDAP_USER_UID = ["uid", "uniqueIdentifier", "mail"]
CFG_EXTERNAL_AUTH_LDAP_MAIL_ENTRY = 'mail'
CFG_EXTERNAL_AUTH_LDAP_GROUP_MEMBERSHIP = 'memberOf'
CFG_EXTERNAL_AUTH_LDAP_GROUP_UID = 'uniqueIdentifier'
CFG_EXTERNAL_AUTH_LDAP_GROUP_NAME = 'displayName'
CFG_EXTERNAL_AUTH_LDAP_HIDDEN_GROUPS = ['EPFL-unit', 'users']
class ExternalAuthLDAP(ExternalAuth):
"""
External authentication example for a custom LDAP-based
authentication service.
"""
def __init__(self):
"""Initialize stuff here"""
ExternalAuth.__init__(self)
self.enforce_external_nicknames = True
def _ldap_try (self, command):
""" Try to run the specified command on the first LDAP server that
is not down."""
for server in CFG_EXTERNAL_AUTH_LDAP_SERVERS:
try:
connection = ldap.initialize(server)
return command(connection)
except ldap.SERVER_DOWN, error_message:
continue
raise InvenioWebAccessExternalAuthError
def auth_user(self, username, password, req=None):
"""
Check USERNAME and PASSWORD against the LDAP system.
Return None if authentication failed, or the email address of the
person if the authentication was successful.
Raise InvenioWebAccessExternalAuthError in case of external troubles.
Note: for SSO the parameter are discarded and overloaded by Shibboleth
variables
"""
if not password:
return None
query = '(|' + ''.join (['(%s=%s)' % (attrib, username)
for attrib in
CFG_EXTERNAL_AUTH_LDAP_USER_UID]) \
+ ')'
def _check (connection):
users = connection.search_s(CFG_EXTERNAL_AUTH_LDAP_CONTEXT,
ldap.SCOPE_SUBTREE,
query)
# We pick the first result, as all the data we are interested
# in should be the same in all the entries.
if len(users):
user_dn, user_info = users [0]
else:
return None
try:
connection.simple_bind_s(user_dn, password)
except ldap.INVALID_CREDENTIALS:
# It is enough to fail on one server to consider the credential
# to be invalid
return None
return user_info[CFG_EXTERNAL_AUTH_LDAP_MAIL_ENTRY][0]
return self._ldap_try(_check)
def user_exists(self, email, req=None):
"""Check the external authentication system for existance of email.
@return True if the user exists, False otherwise
"""
query = '(%s=%s)' % (CFG_EXTERNAL_AUTH_LDAP_MAIL_ENTRY, email)
def _check (connection):
users = connection.search_s(CFG_EXTERNAL_AUTH_LDAP_CONTEXT,
ldap.SCOPE_SUBTREE,
query)
return len(users) != 0
return self._ldap_try(_check)
def fetch_user_nickname(self, username, password, req=None):
"""Given a username and a password, returns the right nickname belonging
to that user (username could be an email).
"""
query = '(|' + ''.join (['(%s=%s)' % (attrib, username)
for attrib in
CFG_EXTERNAL_AUTH_LDAP_USER_UID]) \
+ ')'
def _get_nickname(connection):
users = connection.search_s(CFG_EXTERNAL_AUTH_LDAP_CONTEXT,
ldap.SCOPE_SUBTREE,
query)
# We pick the first result, as all the data we are interested
# in should be the same in all the entries.
if len(users):
user_dn, user_info = users [0]
else:
return None
emails = user_info[CFG_EXTERNAL_AUTH_LDAP_MAIL_ENTRY]
if len(emails):
email = emails[0]
else:
return False
(left_part, right_part) = email.split('@')
nickname = left_part.replace('.', ' ').title()
if right_part != 'epfl.ch':
nickname += ' - ' + right_part
return nickname
return self._ldap_try(_get_nickname)
def fetch_user_groups_membership(self, username, password, req=None):
"""Given a username and a password, returns a dictionary of groups
and their description to which the user is subscribed.
Raise InvenioWebAccessExternalAuthError in case of troubles.
"""
query_person = '(|' + ''.join (['(%s=%s)' % (attrib, username)
for attrib in
CFG_EXTERNAL_AUTH_LDAP_USER_UID]) \
+ ')'
def _get_groups(connection):
users = connection.search_s(CFG_EXTERNAL_AUTH_LDAP_CONTEXT,
ldap.SCOPE_SUBTREE,
query_person)
if len(users):
user_dn, user_info = users [0]
else:
return {}
groups = {}
group_ids = user_info[CFG_EXTERNAL_AUTH_LDAP_GROUP_MEMBERSHIP]
for group_id in group_ids:
query_group = '(%s=%s)' % (CFG_EXTERNAL_AUTH_LDAP_GROUP_UID,
group_id)
ldap_group = connection.search_s(CFG_EXTERNAL_AUTH_LDAP_CONTEXT,
ldap.SCOPE_SUBTREE,
query_group)
if len(ldap_group):
group_dn, group_infos = ldap_group[0]
group_name = group_infos[CFG_EXTERNAL_AUTH_LDAP_GROUP_NAME][0]
if group_name in CFG_EXTERNAL_AUTH_LDAP_HIDDEN_GROUPS:
continue
groups[group_id] = group_name
return groups
return self._ldap_try(_get_groups)
def fetch_user_preferences(self, username, password=None, req=None):
"""Given a username and a password, returns a dictionary of keys and
values, corresponding to external infos and settings.
userprefs = {"telephone": "2392489",
"address": "10th Downing Street"}
(WEBUSER WILL erase all prefs that starts by EXTERNAL_ and will
store: "EXTERNAL_telephone"; all internal preferences can use whatever
name but starting with EXTERNAL). If a pref begins with HIDDEN_ it will
be ignored.
"""
query = '(|' + ''.join (['(%s=%s)' % (attrib, username)
for attrib in
CFG_EXTERNAL_AUTH_LDAP_USER_UID]) \
+ ')'
def _get_personal_infos(connection):
users = connection.search_s(CFG_EXTERNAL_AUTH_LDAP_CONTEXT,
ldap.SCOPE_SUBTREE,
query)
if len(users):
user_dn, user_info = users [0]
return user_info
else:
return {}
return self._ldap_try(_get_personal_infos)

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