matrix-synapse/shared_secret_authenticator.py

124 lines
4.5 KiB
Python

# -*- coding: utf-8 -*-
#
# Shared Secret Authenticator module for Matrix Synapse
# Copyright (C) 2018 Slavi Pantaleev
#
# https://devture.com/
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
# 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 Affero General Public License for more details.
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
#
from typing import Awaitable, Callable, Optional, Tuple
import hashlib
import hmac
import logging
import synapse
from synapse import module_api
logger = logging.getLogger(__name__)
class SharedSecretAuthProvider:
def __init__(self, config: dict, api: module_api):
for k in ('shared_secret',):
if k not in config:
raise KeyError('Required `{0}` configuration key not found'.format(k))
m_login_password_support_enabled = bool(config['m_login_password_support_enabled']) if 'm_login_password_support_enabled' in config else False
com_devture_shared_secret_auth_support_enabled = bool(config['com_devture_shared_secret_auth_support_enabled']) if 'com_devture_shared_secret_auth_support_enabled' in config else True
self.api = api
self.shared_secret = config['shared_secret']
auth_checkers: Optional[Dict[Tuple[str, Tuple], CHECK_AUTH_CALLBACK]] = {}
if com_devture_shared_secret_auth_support_enabled:
auth_checkers[("com.devture.shared_secret_auth", ("token",))] = self.check_com_devture_shared_secret_auth
if m_login_password_support_enabled:
auth_checkers[("m.login.password", ("password",))] = self.check_m_login_password
enabled_login_types = [k[0] for k in auth_checkers]
if len(enabled_login_types) == 0:
raise RuntimeError('At least one login type must be enabled')
logger.info('Enabled login types: %s', enabled_login_types)
api.register_password_auth_provider_callbacks(
auth_checkers=auth_checkers,
)
async def check_com_devture_shared_secret_auth(
self,
username: str,
login_type: str,
login_dict: "synapse.module_api.JsonDict",
) -> Optional[
Tuple[
str,
Optional[Callable[["synapse.module_api.LoginResponse"], Awaitable[None]]],
]
]:
if login_type != "com.devture.shared_secret_auth":
return None
return await self._log_in_username_with_token("com.devture.shared_secret_auth", username, login_dict.get("token"))
async def check_m_login_password(
self,
username: str,
login_type: str,
login_dict: "synapse.module_api.JsonDict",
) -> Optional[
Tuple[
str,
Optional[Callable[["synapse.module_api.LoginResponse"], Awaitable[None]]],
]
]:
if login_type != "m.login.password":
return None
return await self._log_in_username_with_token("m.login.password", username, login_dict.get("password"))
async def _log_in_username_with_token(
self,
login_type: str,
username: str,
token: str,
) -> Optional[
Tuple[
str,
Optional[Callable[["synapse.module_api.LoginResponse"], Awaitable[None]]],
]
]:
logger.info('Authenticating user `%s` with login type `%s`', username, login_type)
full_user_id = self.api.get_qualified_user_id(username)
# The password (token) is supposed to be an HMAC of the full user id, keyed with the shared secret.
given_hmac = token.encode('utf-8')
h = hmac.new(self.shared_secret.encode('utf-8'), full_user_id.encode('utf-8'), hashlib.sha512)
computed_hmac = h.hexdigest().encode('utf-8')
if not hmac.compare_digest(computed_hmac, given_hmac):
logger.info('Bad hmac value for user: %s', full_user_id)
return None
user_info = await self.api.get_userinfo_by_id(full_user_id)
if user_info is None:
logger.info('Refusing to authenticate missing user: %s', full_user_id)
return None
logger.info('Authenticated user: %s', full_user_id)
return full_user_id, None