lemur/lemur/auth/ldap.py

230 lines
8.6 KiB
Python

"""
.. module: lemur.auth.ldap
:platform: Unix
:copyright: (c) 2018 by Netflix Inc., see AUTHORS for more
:license: Apache, see LICENSE for more details.
.. moduleauthor:: Ian Stahnke <ian.stahnke@myob.com>
"""
import ldap
from flask import current_app
from lemur.users import service as user_service
from lemur.roles import service as role_service
from lemur.common.utils import validate_conf, get_psuedo_random_string
class LdapPrincipal:
"""
Provides methods for authenticating against an LDAP server.
"""
def __init__(self, args):
self._ldap_validate_conf()
# setup ldap config
if not args["username"]:
raise Exception("missing ldap username")
if not args["password"]:
self.error_message = "missing ldap password"
raise Exception("missing ldap password")
self.ldap_principal = args["username"]
self.ldap_email_domain = current_app.config.get("LDAP_EMAIL_DOMAIN", None)
if "@" not in self.ldap_principal:
self.ldap_principal = "%s@%s" % (
self.ldap_principal,
self.ldap_email_domain,
)
self.ldap_username = args["username"]
if "@" in self.ldap_username:
self.ldap_username = args["username"].split("@")[0]
self.ldap_password = args["password"]
self.ldap_server = current_app.config.get("LDAP_BIND_URI", None)
self.ldap_base_dn = current_app.config.get("LDAP_BASE_DN", None)
self.ldap_use_tls = current_app.config.get("LDAP_USE_TLS", False)
self.ldap_cacert_file = current_app.config.get("LDAP_CACERT_FILE", None)
self.ldap_default_role = current_app.config.get("LEMUR_DEFAULT_ROLE", None)
self.ldap_required_group = current_app.config.get("LDAP_REQUIRED_GROUP", None)
self.ldap_groups_to_roles = current_app.config.get("LDAP_GROUPS_TO_ROLES", None)
self.ldap_is_active_directory = current_app.config.get(
"LDAP_IS_ACTIVE_DIRECTORY", False
)
self.ldap_attrs = ["memberOf"]
self.ldap_client = None
self.ldap_groups = None
def _update_user(self, roles):
"""
create or update a local user instance.
"""
# try to get user from local database
user = user_service.get_by_email(self.ldap_principal)
# create them a local account
if not user:
user = user_service.create(
self.ldap_username,
get_psuedo_random_string(),
self.ldap_principal,
True,
"", # thumbnailPhotoUrl
list(roles),
)
else:
# we add 'lemur' specific roles, so they do not get marked as removed
for ur in user.roles:
if not ur.third_party:
roles.add(ur)
# update any changes to the user
user_service.update(
user.id,
self.ldap_username,
self.ldap_principal,
user.active,
user.profile_picture,
list(roles),
)
return user
def _authorize(self):
"""
check groups and roles to confirm access.
return a list of roles if ok.
raise an exception on error.
"""
if not self.ldap_principal:
return None
if self.ldap_required_group:
# ensure the user has the required group in their group list
if self.ldap_required_group not in self.ldap_groups:
return None
roles = set()
if self.ldap_default_role:
role = role_service.get_by_name(self.ldap_default_role)
if role:
if not role.third_party:
role = role_service.set_third_party(role.id, third_party_status=True)
roles.add(role)
# update their 'roles'
role = role_service.get_by_name(self.ldap_principal)
if not role:
description = "auto generated role based on owner: {0}".format(
self.ldap_principal
)
role = role_service.create(
self.ldap_principal, description=description, third_party=True
)
if not role.third_party:
role = role_service.set_third_party(role.id, third_party_status=True)
roles.add(role)
if not self.ldap_groups_to_roles:
return roles
for ldap_group_name, role_name in self.ldap_groups_to_roles.items():
role = role_service.get_by_name(role_name)
if role:
if ldap_group_name in self.ldap_groups:
current_app.logger.debug(
"assigning role {0} to ldap user {1}".format(
self.ldap_principal, role
)
)
if not role.third_party:
role = role_service.set_third_party(
role.id, third_party_status=True
)
roles.add(role)
return roles
def authenticate(self):
"""
orchestrate the ldap login.
raise an exception on error.
"""
self._bind()
roles = self._authorize()
if not roles:
raise Exception("ldap authorization failed")
return self._update_user(roles)
def _bind(self):
"""
authenticate an ldap user.
list groups for a user.
raise an exception on error.
"""
if "@" not in self.ldap_principal:
self.ldap_principal = "%s@%s" % (
self.ldap_principal,
self.ldap_email_domain,
)
ldap_filter = "userPrincipalName=%s" % self.ldap_principal
# query ldap for auth
try:
# build a client
if not self.ldap_client:
self.ldap_client = ldap.initialize(self.ldap_server)
# perform a synchronous bind
self.ldap_client.set_option(ldap.OPT_REFERRALS, 0)
if self.ldap_use_tls:
ldap.set_option(ldap.OPT_X_TLS_REQUIRE_CERT, ldap.OPT_X_TLS_NEVER)
self.ldap_client.set_option(ldap.OPT_PROTOCOL_VERSION, 3)
self.ldap_client.set_option(ldap.OPT_X_TLS, ldap.OPT_X_TLS_DEMAND)
self.ldap_client.set_option(ldap.OPT_X_TLS_DEMAND, True)
self.ldap_client.set_option(ldap.OPT_DEBUG_LEVEL, 255)
if self.ldap_cacert_file:
self.ldap_client.set_option(
ldap.OPT_X_TLS_CACERTFILE, self.ldap_cacert_file
)
self.ldap_client.simple_bind_s(self.ldap_principal, self.ldap_password)
except ldap.INVALID_CREDENTIALS:
self.ldap_client.unbind()
raise Exception("The supplied ldap credentials are invalid")
except ldap.SERVER_DOWN:
raise Exception("ldap server unavailable")
except ldap.LDAPError as e:
raise Exception("ldap error: {0}".format(e))
if self.ldap_is_active_directory:
# Lookup user DN, needed to search for group membership
userdn = self.ldap_client.search_s(
self.ldap_base_dn,
ldap.SCOPE_SUBTREE,
ldap_filter,
["distinguishedName"],
)[0][1]["distinguishedName"][0]
userdn = userdn.decode("utf-8")
# Search all groups that have the userDN as a member
groupfilter = "(&(objectclass=group)(member:1.2.840.113556.1.4.1941:={0}))".format(
userdn
)
lgroups = self.ldap_client.search_s(
self.ldap_base_dn, ldap.SCOPE_SUBTREE, groupfilter, ["cn"]
)
# Create a list of group CN's from the result
self.ldap_groups = []
for group in lgroups:
(dn, values) = group
self.ldap_groups.append(values["cn"][0].decode("ascii"))
else:
lgroups = self.ldap_client.search_s(
self.ldap_base_dn, ldap.SCOPE_SUBTREE, ldap_filter, self.ldap_attrs
)[0][1]["memberOf"]
# lgroups is a list of utf-8 encoded strings
# convert to a single string of groups to allow matching
self.ldap_groups = b"".join(lgroups).decode("ascii")
self.ldap_client.unbind()
def _ldap_validate_conf(self):
"""
Confirms required ldap config settings exist.
"""
required_vars = ["LDAP_BIND_URI", "LDAP_BASE_DN", "LDAP_EMAIL_DOMAIN"]
validate_conf(current_app, required_vars)