Implement pluggable password auth

Allows delegating the password auth to an external module. This also
moves the LDAP auth to using this system, allowing it to be removed from
the synapse tree entirely in the future.
This commit is contained in:
Erik Johnston 2016-10-03 10:27:10 +01:00
parent f7bcdbe56c
commit 850b103b36
7 changed files with 486 additions and 401 deletions

View file

@ -20,7 +20,6 @@ from synapse.api.constants import LoginType
from synapse.types import UserID
from synapse.api.errors import AuthError, LoginError, Codes, StoreError, SynapseError
from synapse.util.async import run_on_reactor
from synapse.config.ldap import LDAPMode
from twisted.web.client import PartialDownloadError
@ -29,13 +28,6 @@ import bcrypt
import pymacaroons
import simplejson
try:
import ldap3
import ldap3.core.exceptions
except ImportError:
ldap3 = None
pass
import synapse.util.stringutils as stringutils
@ -61,21 +53,14 @@ class AuthHandler(BaseHandler):
self.sessions = {}
self.INVALID_TOKEN_HTTP_STATUS = 401
self.ldap_enabled = hs.config.ldap_enabled
if self.ldap_enabled:
if not ldap3:
raise RuntimeError(
'Missing ldap3 library. This is required for LDAP Authentication.'
)
self.ldap_mode = hs.config.ldap_mode
self.ldap_uri = hs.config.ldap_uri
self.ldap_start_tls = hs.config.ldap_start_tls
self.ldap_base = hs.config.ldap_base
self.ldap_attributes = hs.config.ldap_attributes
if self.ldap_mode == LDAPMode.SEARCH:
self.ldap_bind_dn = hs.config.ldap_bind_dn
self.ldap_bind_password = hs.config.ldap_bind_password
self.ldap_filter = hs.config.ldap_filter
account_handler = _AccountHandler(
hs, check_user_exists=self.check_user_exists
)
self.password_providers = [
module(config=config, account_handler=account_handler)
for module, config in hs.config.password_providers
]
self.hs = hs # FIXME better possibility to access registrationHandler later?
self.device_handler = hs.get_device_handler()
@ -477,9 +462,10 @@ class AuthHandler(BaseHandler):
Raises:
LoginError if the password was incorrect
"""
valid_ldap = yield self._check_ldap_password(user_id, password)
if valid_ldap:
defer.returnValue(user_id)
for provider in self.password_providers:
is_valid = yield provider.check_password(user_id, password)
if is_valid:
defer.returnValue(user_id)
result = yield self._check_local_password(user_id, password)
defer.returnValue(result)
@ -505,275 +491,6 @@ class AuthHandler(BaseHandler):
raise LoginError(403, "", errcode=Codes.FORBIDDEN)
defer.returnValue(user_id)
def _ldap_simple_bind(self, server, localpart, password):
""" Attempt a simple bind with the credentials
given by the user against the LDAP server.
Returns True, LDAP3Connection
if the bind was successful
Returns False, None
if an error occured
"""
try:
# bind with the the local users ldap credentials
bind_dn = "{prop}={value},{base}".format(
prop=self.ldap_attributes['uid'],
value=localpart,
base=self.ldap_base
)
conn = ldap3.Connection(server, bind_dn, password)
logger.debug(
"Established LDAP connection in simple bind mode: %s",
conn
)
if self.ldap_start_tls:
conn.start_tls()
logger.debug(
"Upgraded LDAP connection in simple bind mode through StartTLS: %s",
conn
)
if conn.bind():
# GOOD: bind okay
logger.debug("LDAP Bind successful in simple bind mode.")
return True, conn
# BAD: bind failed
logger.info(
"Binding against LDAP failed for '%s' failed: %s",
localpart, conn.result['description']
)
conn.unbind()
return False, None
except ldap3.core.exceptions.LDAPException as e:
logger.warn("Error during LDAP authentication: %s", e)
return False, None
def _ldap_authenticated_search(self, server, localpart, password):
""" Attempt to login with the preconfigured bind_dn
and then continue searching and filtering within
the base_dn
Returns (True, LDAP3Connection)
if a single matching DN within the base was found
that matched the filter expression, and with which
a successful bind was achieved
The LDAP3Connection returned is the instance that was used to
verify the password not the one using the configured bind_dn.
Returns (False, None)
if an error occured
"""
try:
conn = ldap3.Connection(
server,
self.ldap_bind_dn,
self.ldap_bind_password
)
logger.debug(
"Established LDAP connection in search mode: %s",
conn
)
if self.ldap_start_tls:
conn.start_tls()
logger.debug(
"Upgraded LDAP connection in search mode through StartTLS: %s",
conn
)
if not conn.bind():
logger.warn(
"Binding against LDAP with `bind_dn` failed: %s",
conn.result['description']
)
conn.unbind()
return False, None
# construct search_filter like (uid=localpart)
query = "({prop}={value})".format(
prop=self.ldap_attributes['uid'],
value=localpart
)
if self.ldap_filter:
# combine with the AND expression
query = "(&{query}{filter})".format(
query=query,
filter=self.ldap_filter
)
logger.debug(
"LDAP search filter: %s",
query
)
conn.search(
search_base=self.ldap_base,
search_filter=query
)
if len(conn.response) == 1:
# GOOD: found exactly one result
user_dn = conn.response[0]['dn']
logger.debug('LDAP search found dn: %s', user_dn)
# unbind and simple bind with user_dn to verify the password
# Note: do not use rebind(), for some reason it did not verify
# the password for me!
conn.unbind()
return self._ldap_simple_bind(server, localpart, password)
else:
# BAD: found 0 or > 1 results, abort!
if len(conn.response) == 0:
logger.info(
"LDAP search returned no results for '%s'",
localpart
)
else:
logger.info(
"LDAP search returned too many (%s) results for '%s'",
len(conn.response), localpart
)
conn.unbind()
return False, None
except ldap3.core.exceptions.LDAPException as e:
logger.warn("Error during LDAP authentication: %s", e)
return False, None
@defer.inlineCallbacks
def _check_ldap_password(self, user_id, password):
""" Attempt to authenticate a user against an LDAP Server
and register an account if none exists.
Returns:
True if authentication against LDAP was successful
"""
if not ldap3 or not self.ldap_enabled:
defer.returnValue(False)
localpart = UserID.from_string(user_id).localpart
try:
server = ldap3.Server(self.ldap_uri)
logger.debug(
"Attempting LDAP connection with %s",
self.ldap_uri
)
if self.ldap_mode == LDAPMode.SIMPLE:
result, conn = self._ldap_simple_bind(
server=server, localpart=localpart, password=password
)
logger.debug(
'LDAP authentication method simple bind returned: %s (conn: %s)',
result,
conn
)
if not result:
defer.returnValue(False)
elif self.ldap_mode == LDAPMode.SEARCH:
result, conn = self._ldap_authenticated_search(
server=server, localpart=localpart, password=password
)
logger.debug(
'LDAP auth method authenticated search returned: %s (conn: %s)',
result,
conn
)
if not result:
defer.returnValue(False)
else:
raise RuntimeError(
'Invalid LDAP mode specified: {mode}'.format(
mode=self.ldap_mode
)
)
try:
logger.info(
"User authenticated against LDAP server: %s",
conn
)
except NameError:
logger.warn("Authentication method yielded no LDAP connection, aborting!")
defer.returnValue(False)
# check if user with user_id exists
if (yield self.check_user_exists(user_id)):
# exists, authentication complete
conn.unbind()
defer.returnValue(True)
else:
# does not exist, fetch metadata for account creation from
# existing ldap connection
query = "({prop}={value})".format(
prop=self.ldap_attributes['uid'],
value=localpart
)
if self.ldap_mode == LDAPMode.SEARCH and self.ldap_filter:
query = "(&{filter}{user_filter})".format(
filter=query,
user_filter=self.ldap_filter
)
logger.debug(
"ldap registration filter: %s",
query
)
conn.search(
search_base=self.ldap_base,
search_filter=query,
attributes=[
self.ldap_attributes['name'],
self.ldap_attributes['mail']
]
)
if len(conn.response) == 1:
attrs = conn.response[0]['attributes']
mail = attrs[self.ldap_attributes['mail']][0]
name = attrs[self.ldap_attributes['name']][0]
# create account
registration_handler = self.hs.get_handlers().registration_handler
user_id, access_token = (
yield registration_handler.register(localpart=localpart)
)
# TODO: bind email, set displayname with data from ldap directory
logger.info(
"Registration based on LDAP data was successful: %d: %s (%s, %)",
user_id,
localpart,
name,
mail
)
defer.returnValue(True)
else:
if len(conn.response) == 0:
logger.warn("LDAP registration failed, no result.")
else:
logger.warn(
"LDAP registration failed, too many results (%s)",
len(conn.response)
)
defer.returnValue(False)
defer.returnValue(False)
except ldap3.core.exceptions.LDAPException as e:
logger.warn("Error during ldap authentication: %s", e)
defer.returnValue(False)
@defer.inlineCallbacks
def issue_access_token(self, user_id, device_id=None):
access_token = self.generate_access_token(user_id)
@ -911,3 +628,30 @@ class AuthHandler(BaseHandler):
stored_hash.encode('utf-8')) == stored_hash
else:
return False
class _AccountHandler(object):
"""A proxy object that gets passed to password auth providers so they
can register new users etc if necessary.
"""
def __init__(self, hs, check_user_exists):
self.hs = hs
self._check_user_exists = check_user_exists
def check_user_exists(self, user_id):
"""Check if user exissts.
Returns:
Deferred(bool)
"""
return self._check_user_exists(user_id)
def register(self, localpart):
"""Registers a new user with given localpart
Returns:
Deferred: a 2-tuple of (user_id, access_token)
"""
reg = self.hs.get_handlers().registration_handler
return reg.register(localpart=localpart)