etesync-server/myauth/ldap.py

97 lines
3.3 KiB
Python

import logging
from django.utils import timezone
from django.conf import settings
from django.core.exceptions import PermissionDenied
from django.contrib.auth import get_user_model
from rest_framework.permissions import BasePermission
import ldap
User = get_user_model()
def ldap_setting(name, default):
"""Wrapper around django.conf.settings"""
return getattr(settings, f"LDAP_{name}", default)
class LDAPConnection:
__instance__ = None
__user_cache = {} # Username -> Valid until
@staticmethod
def get_instance():
"""To get a Singleton"""
if not LDAPConnection.__instance__:
return LDAPConnection()
else:
return LDAPConnection.__instance__
def __init__(self):
# Cache some settings
self.__LDAP_FILTER = ldap_setting("FILTER", "")
self.__LDAP_SEARCH_BASE = ldap_setting("SEARCH_BASE", "")
self.__ldap_connection = ldap.initialize(ldap_setting("SERVER", ""))
try:
self.__ldap_connection.simple_bind_s(ldap_setting("BIND_DN", ""), ldap_setting("BIND_PW", ""))
except ldap.LDAPError as err:
logging.error(f"LDAP Error occuring during bind: {err.desc}")
def __is_cache_valid(self, username):
"""Returns True if the cache entry is still valid. Returns False otherwise."""
if username in self.__user_cache:
if timezone.now() <= self.__user_cache[username]:
# Cache entry is still valid
return True
return False
def __remove_cache(self, username):
del self.__user_cache[username]
def has_user(self, username):
"""
Since we don't care about the password and so authentication
another way, all we care about is whether the user exists.
"""
if self.__is_cache_valid(username):
return True
if username in self.__user_cache:
self.__remove_cache(username)
filterstr = self.__LDAP_FILTER.replace("%s", username)
try:
result = self.__ldap_connection.search_s(self.__LDAP_SEARCH_BASE, ldap.SCOPE_SUBTREE, filterstr=filterstr)
except ldap.NO_RESULTS_RETURNED:
# We handle the specific error first and the the generic error, as
# we may expect ldap.NO_RESULTS_RETURNED, but not any other error
return False
except ldap.LDAPError as err:
logging.error(f"Error occured while performing an LDAP query: {err.desc}")
return False
if len(result) == 1:
self.__user_cache[username] = timezone.now() + timezone.timedelta(hours=1)
return True
return False
class LDAPUserExists(BasePermission):
"""
A permission check which first checks with the LDAP directory if the user
exists.
"""
def has_permission(self, request, view):
return LDAPConnection.get_instance().has_user(request.user.username)
def create_user(*args, **kwargs):
"""
A create_user function which first checks if the user already exists in the
configured LDAP directory.
"""
if not LDAPConnection.get_instance().has_user(kwargs["username"]):
raise PermissionDenied("User not in the LDAP directory.")
_ = kwargs.pop("view")
return User.objects.create_user(*args, **kwargs)