mirror of
https://git.anonymousland.org/anonymousland/synapse-product.git
synced 2024-10-01 08:25:44 -04:00
572 lines
21 KiB
Python
572 lines
21 KiB
Python
# -*- coding: utf-8 -*-
|
|
# Copyright 2020 The Matrix.org Foundation C.I.C.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
import logging
|
|
from typing import TYPE_CHECKING, Awaitable, Callable, Dict, List, Optional
|
|
|
|
import attr
|
|
from typing_extensions import NoReturn
|
|
|
|
from twisted.web.http import Request
|
|
|
|
from synapse.api.errors import RedirectException, SynapseError
|
|
from synapse.http.server import respond_with_html
|
|
from synapse.http.site import SynapseRequest
|
|
from synapse.types import JsonDict, UserID, contains_invalid_mxid_characters
|
|
from synapse.util.async_helpers import Linearizer
|
|
from synapse.util.stringutils import random_string
|
|
|
|
if TYPE_CHECKING:
|
|
from synapse.server import HomeServer
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
class MappingException(Exception):
|
|
"""Used to catch errors when mapping an SSO response to user attributes.
|
|
|
|
Note that the msg that is raised is shown to end-users.
|
|
"""
|
|
|
|
|
|
@attr.s
|
|
class UserAttributes:
|
|
# the localpart of the mxid that the mapper has assigned to the user.
|
|
# if `None`, the mapper has not picked a userid, and the user should be prompted to
|
|
# enter one.
|
|
localpart = attr.ib(type=Optional[str])
|
|
display_name = attr.ib(type=Optional[str], default=None)
|
|
emails = attr.ib(type=List[str], default=attr.Factory(list))
|
|
|
|
|
|
@attr.s(slots=True)
|
|
class UsernameMappingSession:
|
|
"""Data we track about SSO sessions"""
|
|
|
|
# A unique identifier for this SSO provider, e.g. "oidc" or "saml".
|
|
auth_provider_id = attr.ib(type=str)
|
|
|
|
# user ID on the IdP server
|
|
remote_user_id = attr.ib(type=str)
|
|
|
|
# attributes returned by the ID mapper
|
|
display_name = attr.ib(type=Optional[str])
|
|
emails = attr.ib(type=List[str])
|
|
|
|
# An optional dictionary of extra attributes to be provided to the client in the
|
|
# login response.
|
|
extra_login_attributes = attr.ib(type=Optional[JsonDict])
|
|
|
|
# where to redirect the client back to
|
|
client_redirect_url = attr.ib(type=str)
|
|
|
|
# expiry time for the session, in milliseconds
|
|
expiry_time_ms = attr.ib(type=int)
|
|
|
|
|
|
# the HTTP cookie used to track the mapping session id
|
|
USERNAME_MAPPING_SESSION_COOKIE_NAME = b"username_mapping_session"
|
|
|
|
|
|
class SsoHandler:
|
|
# The number of attempts to ask the mapping provider for when generating an MXID.
|
|
_MAP_USERNAME_RETRIES = 1000
|
|
|
|
# the time a UsernameMappingSession remains valid for
|
|
_MAPPING_SESSION_VALIDITY_PERIOD_MS = 15 * 60 * 1000
|
|
|
|
def __init__(self, hs: "HomeServer"):
|
|
self._clock = hs.get_clock()
|
|
self._store = hs.get_datastore()
|
|
self._server_name = hs.hostname
|
|
self._registration_handler = hs.get_registration_handler()
|
|
self._error_template = hs.config.sso_error_template
|
|
self._auth_handler = hs.get_auth_handler()
|
|
|
|
# a lock on the mappings
|
|
self._mapping_lock = Linearizer(name="sso_user_mapping", clock=hs.get_clock())
|
|
|
|
# a map from session id to session data
|
|
self._username_mapping_sessions = {} # type: Dict[str, UsernameMappingSession]
|
|
|
|
def render_error(
|
|
self,
|
|
request: Request,
|
|
error: str,
|
|
error_description: Optional[str] = None,
|
|
code: int = 400,
|
|
) -> None:
|
|
"""Renders the error template and responds with it.
|
|
|
|
This is used to show errors to the user. The template of this page can
|
|
be found under `synapse/res/templates/sso_error.html`.
|
|
|
|
Args:
|
|
request: The incoming request from the browser.
|
|
We'll respond with an HTML page describing the error.
|
|
error: A technical identifier for this error.
|
|
error_description: A human-readable description of the error.
|
|
code: The integer error code (an HTTP response code)
|
|
"""
|
|
html = self._error_template.render(
|
|
error=error, error_description=error_description
|
|
)
|
|
respond_with_html(request, code, html)
|
|
|
|
async def get_sso_user_by_remote_user_id(
|
|
self, auth_provider_id: str, remote_user_id: str
|
|
) -> Optional[str]:
|
|
"""
|
|
Maps the user ID of a remote IdP to a mxid for a previously seen user.
|
|
|
|
If the user has not been seen yet, this will return None.
|
|
|
|
Args:
|
|
auth_provider_id: A unique identifier for this SSO provider, e.g.
|
|
"oidc" or "saml".
|
|
remote_user_id: The user ID according to the remote IdP. This might
|
|
be an e-mail address, a GUID, or some other form. It must be
|
|
unique and immutable.
|
|
|
|
Returns:
|
|
The mxid of a previously seen user.
|
|
"""
|
|
logger.debug(
|
|
"Looking for existing mapping for user %s:%s",
|
|
auth_provider_id,
|
|
remote_user_id,
|
|
)
|
|
|
|
# Check if we already have a mapping for this user.
|
|
previously_registered_user_id = await self._store.get_user_by_external_id(
|
|
auth_provider_id, remote_user_id,
|
|
)
|
|
|
|
# A match was found, return the user ID.
|
|
if previously_registered_user_id is not None:
|
|
logger.info(
|
|
"Found existing mapping for IdP '%s' and remote_user_id '%s': %s",
|
|
auth_provider_id,
|
|
remote_user_id,
|
|
previously_registered_user_id,
|
|
)
|
|
return previously_registered_user_id
|
|
|
|
# No match.
|
|
return None
|
|
|
|
async def complete_sso_login_request(
|
|
self,
|
|
auth_provider_id: str,
|
|
remote_user_id: str,
|
|
request: SynapseRequest,
|
|
client_redirect_url: str,
|
|
sso_to_matrix_id_mapper: Callable[[int], Awaitable[UserAttributes]],
|
|
grandfather_existing_users: Callable[[], Awaitable[Optional[str]]],
|
|
extra_login_attributes: Optional[JsonDict] = None,
|
|
) -> None:
|
|
"""
|
|
Given an SSO ID, retrieve the user ID for it and possibly register the user.
|
|
|
|
This first checks if the SSO ID has previously been linked to a matrix ID,
|
|
if it has that matrix ID is returned regardless of the current mapping
|
|
logic.
|
|
|
|
If a callable is provided for grandfathering users, it is called and can
|
|
potentially return a matrix ID to use. If it does, the SSO ID is linked to
|
|
this matrix ID for subsequent calls.
|
|
|
|
The mapping function is called (potentially multiple times) to generate
|
|
a localpart for the user.
|
|
|
|
If an unused localpart is generated, the user is registered from the
|
|
given user-agent and IP address and the SSO ID is linked to this matrix
|
|
ID for subsequent calls.
|
|
|
|
Finally, we generate a redirect to the supplied redirect uri, with a login token
|
|
|
|
Args:
|
|
auth_provider_id: A unique identifier for this SSO provider, e.g.
|
|
"oidc" or "saml".
|
|
|
|
remote_user_id: The unique identifier from the SSO provider.
|
|
|
|
request: The request to respond to
|
|
|
|
client_redirect_url: The redirect URL passed in by the client.
|
|
|
|
sso_to_matrix_id_mapper: A callable to generate the user attributes.
|
|
The only parameter is an integer which represents the amount of
|
|
times the returned mxid localpart mapping has failed.
|
|
|
|
It is expected that the mapper can raise two exceptions, which
|
|
will get passed through to the caller:
|
|
|
|
MappingException if there was a problem mapping the response
|
|
to the user.
|
|
RedirectException to redirect to an additional page (e.g.
|
|
to prompt the user for more information).
|
|
|
|
grandfather_existing_users: A callable which can return an previously
|
|
existing matrix ID. The SSO ID is then linked to the returned
|
|
matrix ID.
|
|
|
|
extra_login_attributes: An optional dictionary of extra
|
|
attributes to be provided to the client in the login response.
|
|
|
|
Raises:
|
|
MappingException if there was a problem mapping the response to a user.
|
|
RedirectException: if the mapping provider needs to redirect the user
|
|
to an additional page. (e.g. to prompt for more information)
|
|
|
|
"""
|
|
# grab a lock while we try to find a mapping for this user. This seems...
|
|
# optimistic, especially for implementations that end up redirecting to
|
|
# interstitial pages.
|
|
with await self._mapping_lock.queue(auth_provider_id):
|
|
# first of all, check if we already have a mapping for this user
|
|
user_id = await self.get_sso_user_by_remote_user_id(
|
|
auth_provider_id, remote_user_id,
|
|
)
|
|
|
|
# Check for grandfathering of users.
|
|
if not user_id:
|
|
user_id = await grandfather_existing_users()
|
|
if user_id:
|
|
# Future logins should also match this user ID.
|
|
await self._store.record_user_external_id(
|
|
auth_provider_id, remote_user_id, user_id
|
|
)
|
|
|
|
# Otherwise, generate a new user.
|
|
if not user_id:
|
|
attributes = await self._call_attribute_mapper(sso_to_matrix_id_mapper)
|
|
|
|
if attributes.localpart is None:
|
|
# the mapper doesn't return a username. bail out with a redirect to
|
|
# the username picker.
|
|
await self._redirect_to_username_picker(
|
|
auth_provider_id,
|
|
remote_user_id,
|
|
attributes,
|
|
client_redirect_url,
|
|
extra_login_attributes,
|
|
)
|
|
|
|
user_id = await self._register_mapped_user(
|
|
attributes,
|
|
auth_provider_id,
|
|
remote_user_id,
|
|
request.get_user_agent(""),
|
|
request.getClientIP(),
|
|
)
|
|
|
|
await self._auth_handler.complete_sso_login(
|
|
user_id, request, client_redirect_url, extra_login_attributes
|
|
)
|
|
|
|
async def _call_attribute_mapper(
|
|
self, sso_to_matrix_id_mapper: Callable[[int], Awaitable[UserAttributes]],
|
|
) -> UserAttributes:
|
|
"""Call the attribute mapper function in a loop, until we get a unique userid"""
|
|
for i in range(self._MAP_USERNAME_RETRIES):
|
|
try:
|
|
attributes = await sso_to_matrix_id_mapper(i)
|
|
except (RedirectException, MappingException):
|
|
# Mapping providers are allowed to issue a redirect (e.g. to ask
|
|
# the user for more information) and can issue a mapping exception
|
|
# if a name cannot be generated.
|
|
raise
|
|
except Exception as e:
|
|
# Any other exception is unexpected.
|
|
raise MappingException(
|
|
"Could not extract user attributes from SSO response."
|
|
) from e
|
|
|
|
logger.debug(
|
|
"Retrieved user attributes from user mapping provider: %r (attempt %d)",
|
|
attributes,
|
|
i,
|
|
)
|
|
|
|
if not attributes.localpart:
|
|
# the mapper has not picked a localpart
|
|
return attributes
|
|
|
|
# Check if this mxid already exists
|
|
user_id = UserID(attributes.localpart, self._server_name).to_string()
|
|
if not await self._store.get_users_by_id_case_insensitive(user_id):
|
|
# This mxid is free
|
|
break
|
|
else:
|
|
# Unable to generate a username in 1000 iterations
|
|
# Break and return error to the user
|
|
raise MappingException(
|
|
"Unable to generate a Matrix ID from the SSO response"
|
|
)
|
|
return attributes
|
|
|
|
async def _redirect_to_username_picker(
|
|
self,
|
|
auth_provider_id: str,
|
|
remote_user_id: str,
|
|
attributes: UserAttributes,
|
|
client_redirect_url: str,
|
|
extra_login_attributes: Optional[JsonDict],
|
|
) -> NoReturn:
|
|
"""Creates a UsernameMappingSession and redirects the browser
|
|
|
|
Called if the user mapping provider doesn't return a localpart for a new user.
|
|
Raises a RedirectException which redirects the browser to the username picker.
|
|
|
|
Args:
|
|
auth_provider_id: A unique identifier for this SSO provider, e.g.
|
|
"oidc" or "saml".
|
|
|
|
remote_user_id: The unique identifier from the SSO provider.
|
|
|
|
attributes: the user attributes returned by the user mapping provider.
|
|
|
|
client_redirect_url: The redirect URL passed in by the client, which we
|
|
will eventually redirect back to.
|
|
|
|
extra_login_attributes: An optional dictionary of extra
|
|
attributes to be provided to the client in the login response.
|
|
|
|
Raises:
|
|
RedirectException
|
|
"""
|
|
session_id = random_string(16)
|
|
now = self._clock.time_msec()
|
|
session = UsernameMappingSession(
|
|
auth_provider_id=auth_provider_id,
|
|
remote_user_id=remote_user_id,
|
|
display_name=attributes.display_name,
|
|
emails=attributes.emails,
|
|
client_redirect_url=client_redirect_url,
|
|
expiry_time_ms=now + self._MAPPING_SESSION_VALIDITY_PERIOD_MS,
|
|
extra_login_attributes=extra_login_attributes,
|
|
)
|
|
|
|
self._username_mapping_sessions[session_id] = session
|
|
logger.info("Recorded registration session id %s", session_id)
|
|
|
|
# Set the cookie and redirect to the username picker
|
|
e = RedirectException(b"/_synapse/client/pick_username")
|
|
e.cookies.append(
|
|
b"%s=%s; path=/"
|
|
% (USERNAME_MAPPING_SESSION_COOKIE_NAME, session_id.encode("ascii"))
|
|
)
|
|
raise e
|
|
|
|
async def _register_mapped_user(
|
|
self,
|
|
attributes: UserAttributes,
|
|
auth_provider_id: str,
|
|
remote_user_id: str,
|
|
user_agent: str,
|
|
ip_address: str,
|
|
) -> str:
|
|
"""Register a new SSO user.
|
|
|
|
This is called once we have successfully mapped the remote user id onto a local
|
|
user id, one way or another.
|
|
|
|
Args:
|
|
attributes: user attributes returned by the user mapping provider,
|
|
including a non-empty localpart.
|
|
|
|
auth_provider_id: A unique identifier for this SSO provider, e.g.
|
|
"oidc" or "saml".
|
|
|
|
remote_user_id: The unique identifier from the SSO provider.
|
|
|
|
user_agent: The user-agent in the HTTP request (used for potential
|
|
shadow-banning.)
|
|
|
|
ip_address: The IP address of the requester (used for potential
|
|
shadow-banning.)
|
|
|
|
Raises:
|
|
a MappingException if the localpart is invalid.
|
|
|
|
a SynapseError with code 400 and errcode Codes.USER_IN_USE if the localpart
|
|
is already taken.
|
|
"""
|
|
|
|
# Since the localpart is provided via a potentially untrusted module,
|
|
# ensure the MXID is valid before registering.
|
|
if not attributes.localpart or contains_invalid_mxid_characters(
|
|
attributes.localpart
|
|
):
|
|
raise MappingException("localpart is invalid: %s" % (attributes.localpart,))
|
|
|
|
logger.debug("Mapped SSO user to local part %s", attributes.localpart)
|
|
registered_user_id = await self._registration_handler.register_user(
|
|
localpart=attributes.localpart,
|
|
default_display_name=attributes.display_name,
|
|
bind_emails=attributes.emails,
|
|
user_agent_ips=[(user_agent, ip_address)],
|
|
)
|
|
|
|
await self._store.record_user_external_id(
|
|
auth_provider_id, remote_user_id, registered_user_id
|
|
)
|
|
return registered_user_id
|
|
|
|
async def complete_sso_ui_auth_request(
|
|
self,
|
|
auth_provider_id: str,
|
|
remote_user_id: str,
|
|
ui_auth_session_id: str,
|
|
request: Request,
|
|
) -> None:
|
|
"""
|
|
Given an SSO ID, retrieve the user ID for it and complete UIA.
|
|
|
|
Note that this requires that the user is mapped in the "user_external_ids"
|
|
table. This will be the case if they have ever logged in via SAML or OIDC in
|
|
recentish synapse versions, but may not be for older users.
|
|
|
|
Args:
|
|
auth_provider_id: A unique identifier for this SSO provider, e.g.
|
|
"oidc" or "saml".
|
|
remote_user_id: The unique identifier from the SSO provider.
|
|
ui_auth_session_id: The ID of the user-interactive auth session.
|
|
request: The request to complete.
|
|
"""
|
|
|
|
user_id = await self.get_sso_user_by_remote_user_id(
|
|
auth_provider_id, remote_user_id,
|
|
)
|
|
|
|
if not user_id:
|
|
logger.warning(
|
|
"Remote user %s/%s has not previously logged in here: UIA will fail",
|
|
auth_provider_id,
|
|
remote_user_id,
|
|
)
|
|
# Let the UIA flow handle this the same as if they presented creds for a
|
|
# different user.
|
|
user_id = ""
|
|
|
|
await self._auth_handler.complete_sso_ui_auth(
|
|
user_id, ui_auth_session_id, request
|
|
)
|
|
|
|
async def check_username_availability(
|
|
self, localpart: str, session_id: str,
|
|
) -> bool:
|
|
"""Handle an "is username available" callback check
|
|
|
|
Args:
|
|
localpart: desired localpart
|
|
session_id: the session id for the username picker
|
|
Returns:
|
|
True if the username is available
|
|
Raises:
|
|
SynapseError if the localpart is invalid or the session is unknown
|
|
"""
|
|
|
|
# make sure that there is a valid mapping session, to stop people dictionary-
|
|
# scanning for accounts
|
|
|
|
self._expire_old_sessions()
|
|
session = self._username_mapping_sessions.get(session_id)
|
|
if not session:
|
|
logger.info("Couldn't find session id %s", session_id)
|
|
raise SynapseError(400, "unknown session")
|
|
|
|
logger.info(
|
|
"[session %s] Checking for availability of username %s",
|
|
session_id,
|
|
localpart,
|
|
)
|
|
|
|
if contains_invalid_mxid_characters(localpart):
|
|
raise SynapseError(400, "localpart is invalid: %s" % (localpart,))
|
|
user_id = UserID(localpart, self._server_name).to_string()
|
|
user_infos = await self._store.get_users_by_id_case_insensitive(user_id)
|
|
|
|
logger.info("[session %s] users: %s", session_id, user_infos)
|
|
return not user_infos
|
|
|
|
async def handle_submit_username_request(
|
|
self, request: SynapseRequest, localpart: str, session_id: str
|
|
) -> None:
|
|
"""Handle a request to the username-picker 'submit' endpoint
|
|
|
|
Will serve an HTTP response to the request.
|
|
|
|
Args:
|
|
request: HTTP request
|
|
localpart: localpart requested by the user
|
|
session_id: ID of the username mapping session, extracted from a cookie
|
|
"""
|
|
self._expire_old_sessions()
|
|
session = self._username_mapping_sessions.get(session_id)
|
|
if not session:
|
|
logger.info("Couldn't find session id %s", session_id)
|
|
raise SynapseError(400, "unknown session")
|
|
|
|
logger.info("[session %s] Registering localpart %s", session_id, localpart)
|
|
|
|
attributes = UserAttributes(
|
|
localpart=localpart,
|
|
display_name=session.display_name,
|
|
emails=session.emails,
|
|
)
|
|
|
|
# the following will raise a 400 error if the username has been taken in the
|
|
# meantime.
|
|
user_id = await self._register_mapped_user(
|
|
attributes,
|
|
session.auth_provider_id,
|
|
session.remote_user_id,
|
|
request.get_user_agent(""),
|
|
request.getClientIP(),
|
|
)
|
|
|
|
logger.info("[session %s] Registered userid %s", session_id, user_id)
|
|
|
|
# delete the mapping session and the cookie
|
|
del self._username_mapping_sessions[session_id]
|
|
|
|
# delete the cookie
|
|
request.addCookie(
|
|
USERNAME_MAPPING_SESSION_COOKIE_NAME,
|
|
b"",
|
|
expires=b"Thu, 01 Jan 1970 00:00:00 GMT",
|
|
path=b"/",
|
|
)
|
|
|
|
await self._auth_handler.complete_sso_login(
|
|
user_id,
|
|
request,
|
|
session.client_redirect_url,
|
|
session.extra_login_attributes,
|
|
)
|
|
|
|
def _expire_old_sessions(self):
|
|
to_expire = []
|
|
now = int(self._clock.time_msec())
|
|
|
|
for session_id, session in self._username_mapping_sessions.items():
|
|
if session.expiry_time_ms <= now:
|
|
to_expire.append(session_id)
|
|
|
|
for session_id in to_expire:
|
|
logger.info("Expiring mapping session %s", session_id)
|
|
del self._username_mapping_sessions[session_id]
|