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# -*- coding: utf-8 -*- 

# This program 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 version 3 for 

# more details. 

# 

# You should have received a copy of the GNU General Public License version 3 

# along with this program; if not, write to the Free Software Foundation, Inc., 51 

# Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 

# 

# (c) 2015-2016 Valentin Samir 

"""Some authentication classes for the CAS""" 

from django.conf import settings 

from django.contrib.auth import get_user_model 

from django.utils import timezone 

from django.db import connections, DatabaseError 

 

import warnings 

from datetime import timedelta 

from six.moves import range 

try: # pragma: no cover 

import MySQLdb 

import MySQLdb.cursors 

except ImportError: 

MySQLdb = None 

 

 

try: # pragma: no cover 

import ldap3 

import ldap3.core.exceptions 

except ImportError: 

ldap3 = None 

 

from .models import FederatedUser, UserAttributes 

from .utils import check_password, dictfetchall 

 

 

class AuthUser(object): 

""" 

Authentication base class 

 

:param unicode username: A username, stored in the :attr:`username` class attribute. 

""" 

 

#: username used to instanciate the current object 

username = None 

 

def __init__(self, username): 

self.username = username 

 

def test_password(self, password): 

""" 

Tests ``password`` against the user-supplied password. 

 

:raises NotImplementedError: always. The method need to be implemented by subclasses 

""" 

raise NotImplementedError() 

 

def attributs(self): 

""" 

The user attributes. 

 

raises NotImplementedError: always. The method need to be implemented by subclasses 

""" 

raise NotImplementedError() 

 

 

class DummyAuthUser(AuthUser): # pragma: no cover 

""" 

A Dummy authentication class. Authentication always fails 

 

:param unicode username: A username, stored in the :attr:`username<AuthUser.username>` 

class attribute. There is no valid value for this attribute here. 

""" 

 

def test_password(self, password): 

""" 

Tests ``password`` against the user-supplied password. 

 

:param unicode password: a clear text password as submited by the user. 

:return: always ``False`` 

:rtype: bool 

""" 

return False 

 

def attributs(self): 

""" 

The user attributes. 

 

:return: en empty :class:`dict`. 

:rtype: dict 

""" 

return {} 

 

 

class TestAuthUser(AuthUser): 

""" 

A test authentication class only working for one unique user. 

 

:param unicode username: A username, stored in the :attr:`username<AuthUser.username>` 

class attribute. The uniq valid value is ``settings.CAS_TEST_USER``. 

""" 

 

def test_password(self, password): 

""" 

Tests ``password`` against the user-supplied password. 

 

:param unicode password: a clear text password as submited by the user. 

:return: ``True`` if :attr:`username<AuthUser.username>` is valid and 

``password`` is equal to ``settings.CAS_TEST_PASSWORD``, ``False`` otherwise. 

:rtype: bool 

""" 

return self.username == settings.CAS_TEST_USER and password == settings.CAS_TEST_PASSWORD 

 

def attributs(self): 

""" 

The user attributes. 

 

:return: the ``settings.CAS_TEST_ATTRIBUTES`` :class:`dict` if 

:attr:`username<AuthUser.username>` is valid, an empty :class:`dict` otherwise. 

:rtype: dict 

""" 

if self.username == settings.CAS_TEST_USER: 

return settings.CAS_TEST_ATTRIBUTES 

else: # pragma: no cover (should not happen) 

return {} 

 

 

class DBAuthUser(AuthUser): # pragma: no cover 

"""base class for databate based auth classes""" 

#: DB user attributes as a :class:`dict` if the username is found in the database. 

user = None 

 

def attributs(self): 

""" 

The user attributes. 

 

:return: a :class:`dict` with the user attributes. Attributes may be :func:`unicode` 

or :class:`list` of :func:`unicode`. If the user do not exists, the returned 

:class:`dict` is empty. 

:rtype: dict 

""" 

if self.user: 

return self.user 

else: 

return {} 

 

 

class MysqlAuthUser(DBAuthUser): # pragma: no cover 

""" 

DEPRECATED, use :class:`SqlAuthUser` instead. 

 

A mysql authentication class: authenticate user against a mysql database 

 

:param unicode username: A username, stored in the :attr:`username<AuthUser.username>` 

class attribute. Valid value are fetched from the MySQL database set with 

``settings.CAS_SQL_*`` settings parameters using the query 

``settings.CAS_SQL_USER_QUERY``. 

""" 

 

def __init__(self, username): 

warnings.warn( 

( 

"MysqlAuthUser authentication class is deprecated: " 

"use cas_server.auth.SqlAuthUser instead" 

), 

UserWarning 

) 

# see the connect function at 

# http://mysql-python.sourceforge.net/MySQLdb.html#functions-and-attributes 

# for possible mysql config parameters. 

mysql_config = { 

"user": settings.CAS_SQL_USERNAME, 

"passwd": settings.CAS_SQL_PASSWORD, 

"db": settings.CAS_SQL_DBNAME, 

"host": settings.CAS_SQL_HOST, 

"charset": settings.CAS_SQL_DBCHARSET, 

"cursorclass": MySQLdb.cursors.DictCursor 

} 

if not MySQLdb: 

raise RuntimeError("Please install MySQLdb before using the MysqlAuthUser backend") 

conn = MySQLdb.connect(**mysql_config) 

curs = conn.cursor() 

if curs.execute(settings.CAS_SQL_USER_QUERY, (username,)) == 1: 

self.user = curs.fetchone() 

super(MysqlAuthUser, self).__init__(self.user['username']) 

else: 

super(MysqlAuthUser, self).__init__(username) 

 

def test_password(self, password): 

""" 

Tests ``password`` against the user-supplied password. 

 

:param unicode password: a clear text password as submited by the user. 

:return: ``True`` if :attr:`username<AuthUser.username>` is valid and ``password`` is 

correct, ``False`` otherwise. 

:rtype: bool 

""" 

if self.user: 

return check_password( 

settings.CAS_SQL_PASSWORD_CHECK, 

password, 

self.user["password"], 

settings.CAS_SQL_DBCHARSET 

) 

else: 

return False 

 

 

class SqlAuthUser(DBAuthUser): # pragma: no cover 

""" 

A SQL authentication class: authenticate user against a SQL database. The SQL database 

must be configures in settings.py as ``settings.DATABASES['cas_server']``. 

 

:param unicode username: A username, stored in the :attr:`username<AuthUser.username>` 

class attribute. Valid value are fetched from the MySQL database set with 

``settings.CAS_SQL_*`` settings parameters using the query 

``settings.CAS_SQL_USER_QUERY``. 

""" 

 

def __init__(self, username): 

if "cas_server" not in connections: 

raise RuntimeError("Please configure the 'cas_server' database in settings.DATABASES") 

for retry_nb in range(3): 

try: 

with connections["cas_server"].cursor() as curs: 

curs.execute(settings.CAS_SQL_USER_QUERY, (username,)) 

results = dictfetchall(curs) 

if len(results) == 1: 

self.user = results[0] 

super(SqlAuthUser, self).__init__(self.user['username']) 

else: 

super(SqlAuthUser, self).__init__(username) 

break 

except DatabaseError: 

connections["cas_server"].close() 

if retry_nb == 2: 

raise 

 

def test_password(self, password): 

""" 

Tests ``password`` against the user-supplied password. 

 

:param unicode password: a clear text password as submited by the user. 

:return: ``True`` if :attr:`username<AuthUser.username>` is valid and ``password`` is 

correct, ``False`` otherwise. 

:rtype: bool 

""" 

if self.user: 

return check_password( 

settings.CAS_SQL_PASSWORD_CHECK, 

password, 

self.user["password"], 

settings.CAS_SQL_PASSWORD_CHARSET 

) 

else: 

return False 

 

 

class LdapAuthUser(DBAuthUser): # pragma: no cover 

""" 

A ldap authentication class: authenticate user against a ldap database 

 

:param unicode username: A username, stored in the :attr:`username<AuthUser.username>` 

class attribute. Valid value are fetched from the ldap database set with 

``settings.CAS_LDAP_*`` settings parameters. 

""" 

 

_conn = None 

 

@classmethod 

def get_conn(cls): 

"""Return a connection object to the ldap database""" 

conn = cls._conn 

if conn is None or conn.closed: 

conn = ldap3.Connection( 

settings.CAS_LDAP_SERVER, 

settings.CAS_LDAP_USER, 

settings.CAS_LDAP_PASSWORD, 

auto_bind=True 

) 

cls._conn = conn 

return conn 

 

def __init__(self, username): 

if not ldap3: 

raise RuntimeError("Please install ldap3 before using the LdapAuthUser backend") 

if not settings.CAS_LDAP_BASE_DN: 

raise ValueError( 

"You must define CAS_LDAP_BASE_DN for using the ldap authentication backend" 

) 

# in case we got deconnected from the database, retry to connect 2 times 

for retry_nb in range(3): 

try: 

conn = self.get_conn() 

if conn.search( 

settings.CAS_LDAP_BASE_DN, 

settings.CAS_LDAP_USER_QUERY % ldap3.utils.conv.escape_bytes(username), 

attributes=ldap3.ALL_ATTRIBUTES 

) and len(conn.entries) == 1: 

# try the new ldap3>=2 API 

try: 

user = conn.entries[0].entry_attributes_as_dict 

# store the user dn 

user["dn"] = conn.entries[0].entry_dn 

# fallback to ldap3<2 API 

except ( 

ldap3.core.exceptions.LDAPKeyError, # ldap3<1 exception 

ldap3.core.exceptions.LDAPAttributeError # ldap3<2 exception 

): 

user = conn.entries[0].entry_get_attributes_dict() 

# store the user dn 

user["dn"] = conn.entries[0].entry_get_dn() 

if user.get(settings.CAS_LDAP_USERNAME_ATTR): 

self.user = user 

super(LdapAuthUser, self).__init__(user[settings.CAS_LDAP_USERNAME_ATTR][0]) 

else: 

super(LdapAuthUser, self).__init__(username) 

else: 

super(LdapAuthUser, self).__init__(username) 

break 

except ldap3.core.exceptions.LDAPCommunicationError: 

if retry_nb == 2: 

raise 

 

def test_password(self, password): 

""" 

Tests ``password`` against the user-supplied password. 

 

:param unicode password: a clear text password as submited by the user. 

:return: ``True`` if :attr:`username<AuthUser.username>` is valid and ``password`` is 

correct, ``False`` otherwise. 

:rtype: bool 

""" 

if self.user and settings.CAS_LDAP_PASSWORD_CHECK == "bind": 

try: 

conn = ldap3.Connection( 

settings.CAS_LDAP_SERVER, 

self.user["dn"], 

password, 

auto_bind=True 

) 

try: 

# fetch the user attribute 

if conn.search( 

settings.CAS_LDAP_BASE_DN, 

settings.CAS_LDAP_USER_QUERY % ldap3.utils.conv.escape_bytes(self.username), 

attributes=ldap3.ALL_ATTRIBUTES 

) and len(conn.entries) == 1: 

# try the ldap3>=2 API 

try: 

attributes = conn.entries[0].entry_attributes_as_dict 

# store the user dn 

attributes["dn"] = conn.entries[0].entry_dn 

# fallback to ldap<2 API 

except ( 

ldap3.core.exceptions.LDAPKeyError, # ldap3<1 exception 

ldap3.core.exceptions.LDAPAttributeError # ldap3<2 exception 

): 

attributes = conn.entries[0].entry_get_attributes_dict() 

attributes["dn"] = conn.entries[0].entry_get_dn() 

# cache the attributes locally as we wont have access to the user password 

# later. 

user = UserAttributes.objects.get_or_create(username=self.username)[0] 

user.attributs = attributes 

user.save() 

finally: 

conn.unbind() 

return True 

except ( 

ldap3.core.exceptions.LDAPBindError, 

ldap3.core.exceptions.LDAPCommunicationError 

): 

return False 

elif self.user and self.user.get(settings.CAS_LDAP_PASSWORD_ATTR): 

return check_password( 

settings.CAS_LDAP_PASSWORD_CHECK, 

password, 

self.user[settings.CAS_LDAP_PASSWORD_ATTR][0], 

settings.CAS_LDAP_PASSWORD_CHARSET 

) 

else: 

return False 

 

def attributs(self): 

""" 

The user attributes. 

 

:return: a :class:`dict` with the user attributes. Attributes may be :func:`unicode` 

or :class:`list` of :func:`unicode`. If the user do not exists, the returned 

:class:`dict` is empty. 

:rtype: dict 

:raises NotImplementedError: if the password check method in `CAS_LDAP_PASSWORD_CHECK` 

do not allow to fetch the attributes without the user credentials. 

""" 

if settings.CAS_LDAP_PASSWORD_CHECK == "bind": 

raise NotImplementedError() 

else: 

return super(LdapAuthUser, self).attributs() 

 

 

class DjangoAuthUser(AuthUser): # pragma: no cover 

""" 

A django auth class: authenticate user against django internal users 

 

:param unicode username: A username, stored in the :attr:`username<AuthUser.username>` 

class attribute. Valid value are usernames of django internal users. 

""" 

#: a django user object if the username is found. The user model is retreived 

#: using :func:`django.contrib.auth.get_user_model`. 

user = None 

 

def __init__(self, username): 

User = get_user_model() 

try: 

self.user = User.objects.get(username=username) 

except User.DoesNotExist: 

pass 

super(DjangoAuthUser, self).__init__(username) 

 

def test_password(self, password): 

""" 

Tests ``password`` against the user-supplied password. 

 

:param unicode password: a clear text password as submited by the user. 

:return: ``True`` if :attr:`user` is valid and ``password`` is 

correct, ``False`` otherwise. 

:rtype: bool 

""" 

if self.user: 

return self.user.check_password(password) 

else: 

return False 

 

def attributs(self): 

""" 

The user attributes, defined as the fields on the :attr:`user` object. 

 

:return: a :class:`dict` with the :attr:`user` object fields. Attributes may be 

If the user do not exists, the returned :class:`dict` is empty. 

:rtype: dict 

""" 

if self.user: 

attr = {} 

# _meta.get_fields() is from the new documented _meta interface in django 1.8 

try: 

field_names = [ 

field.attname for field in self.user._meta.get_fields() 

if hasattr(field, "attname") 

] 

# backward compatibility with django 1.7 

except AttributeError: # pragma: no cover (only used by django 1.7) 

field_names = self.user._meta.get_all_field_names() 

for name in field_names: 

attr[name] = getattr(self.user, name) 

 

# unfold user_permissions many to many relation 

if 'user_permissions' in attr: 

attr['user_permissions'] = [ 

( 

u"%s.%s" % ( 

perm.content_type.model_class().__module__, 

perm.content_type.model_class().__name__ 

), 

perm.codename 

) for perm in attr['user_permissions'].filter() 

] 

 

# unfold group many to many relation 

if 'groups' in attr: 

attr['groups'] = [group.name for group in attr['groups'].filter()] 

 

return attr 

else: 

return {} 

 

 

class CASFederateAuth(AuthUser): 

""" 

Authentication class used then CAS_FEDERATE is True 

 

:param unicode username: A username, stored in the :attr:`username<AuthUser.username>` 

class attribute. Valid value are usernames of 

:class:`FederatedUser<cas_server.models.FederatedUser>` object. 

:class:`FederatedUser<cas_server.models.FederatedUser>` object are created on CAS 

backends successful ticket validation. 

""" 

#: a :class`FederatedUser<cas_server.models.FederatedUser>` object if ``username`` is found. 

user = None 

 

def __init__(self, username): 

try: 

self.user = FederatedUser.get_from_federated_username(username) 

super(CASFederateAuth, self).__init__( 

self.user.federated_username 

) 

except FederatedUser.DoesNotExist: 

super(CASFederateAuth, self).__init__(username) 

 

def test_password(self, ticket): 

""" 

Tests ``password`` against the user-supplied password. 

 

:param unicode password: The CAS tickets just used to validate the user authentication 

against its CAS backend. 

:return: ``True`` if :attr:`user` is valid and ``password`` is 

a ticket validated less than ``settings.CAS_TICKET_VALIDITY`` secondes and has not 

being previously used for authenticated this 

:class:`FederatedUser<cas_server.models.FederatedUser>`. ``False`` otherwise. 

:rtype: bool 

""" 

if not self.user or not self.user.ticket: 

return False 

else: 

return ( 

ticket == self.user.ticket and 

self.user.last_update > 

(timezone.now() - timedelta(seconds=settings.CAS_TICKET_VALIDITY)) 

) 

 

def attributs(self): 

""" 

The user attributes, as returned by the CAS backend. 

 

:return: :obj:`FederatedUser.attributs<cas_server.models.FederatedUser.attributs>`. 

If the user do not exists, the returned :class:`dict` is empty. 

:rtype: dict 

""" 

if not self.user: # pragma: no cover (should not happen) 

return {} 

else: 

return self.user.attributs