mirror of
https://git.anonymousland.org/anonymousland/synapse.git
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36ba73f53d
* SsoHandler: remove inheritance from BaseHandler * Simplify the flow for SSO UIA We don't need to do all the magic for mapping users when we are doing UIA, so let's factor that out.
1140 lines
43 KiB
Python
1140 lines
43 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2020 Quentin Gliech
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import inspect
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import logging
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from typing import TYPE_CHECKING, Dict, Generic, List, Optional, Tuple, TypeVar
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from urllib.parse import urlencode
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import attr
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import pymacaroons
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from authlib.common.security import generate_token
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from authlib.jose import JsonWebToken
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from authlib.oauth2.auth import ClientAuth
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from authlib.oauth2.rfc6749.parameters import prepare_grant_uri
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from authlib.oidc.core import CodeIDToken, ImplicitIDToken, UserInfo
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from authlib.oidc.discovery import OpenIDProviderMetadata, get_well_known_url
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from jinja2 import Environment, Template
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from pymacaroons.exceptions import (
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MacaroonDeserializationException,
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MacaroonInvalidSignatureException,
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)
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from typing_extensions import TypedDict
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from twisted.web.client import readBody
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from synapse.config import ConfigError
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from synapse.handlers._base import BaseHandler
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from synapse.handlers.sso import MappingException, UserAttributes
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from synapse.http.site import SynapseRequest
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from synapse.logging.context import make_deferred_yieldable
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from synapse.types import JsonDict, UserID, map_username_to_mxid_localpart
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from synapse.util import json_decoder
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if TYPE_CHECKING:
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from synapse.server import HomeServer
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logger = logging.getLogger(__name__)
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SESSION_COOKIE_NAME = b"oidc_session"
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#: A token exchanged from the token endpoint, as per RFC6749 sec 5.1. and
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#: OpenID.Core sec 3.1.3.3.
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Token = TypedDict(
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"Token",
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{
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"access_token": str,
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"token_type": str,
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"id_token": Optional[str],
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"refresh_token": Optional[str],
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"expires_in": int,
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"scope": Optional[str],
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},
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)
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#: A JWK, as per RFC7517 sec 4. The type could be more precise than that, but
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#: there is no real point of doing this in our case.
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JWK = Dict[str, str]
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#: A JWK Set, as per RFC7517 sec 5.
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JWKS = TypedDict("JWKS", {"keys": List[JWK]})
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class OidcError(Exception):
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"""Used to catch errors when calling the token_endpoint
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"""
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def __init__(self, error, error_description=None):
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self.error = error
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self.error_description = error_description
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def __str__(self):
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if self.error_description:
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return "{}: {}".format(self.error, self.error_description)
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return self.error
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class OidcHandler(BaseHandler):
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"""Handles requests related to the OpenID Connect login flow.
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"""
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def __init__(self, hs: "HomeServer"):
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super().__init__(hs)
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self._callback_url = hs.config.oidc_callback_url # type: str
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self._scopes = hs.config.oidc_scopes # type: List[str]
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self._user_profile_method = hs.config.oidc_user_profile_method # type: str
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self._client_auth = ClientAuth(
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hs.config.oidc_client_id,
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hs.config.oidc_client_secret,
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hs.config.oidc_client_auth_method,
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) # type: ClientAuth
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self._client_auth_method = hs.config.oidc_client_auth_method # type: str
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self._provider_metadata = OpenIDProviderMetadata(
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issuer=hs.config.oidc_issuer,
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authorization_endpoint=hs.config.oidc_authorization_endpoint,
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token_endpoint=hs.config.oidc_token_endpoint,
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userinfo_endpoint=hs.config.oidc_userinfo_endpoint,
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jwks_uri=hs.config.oidc_jwks_uri,
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) # type: OpenIDProviderMetadata
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self._provider_needs_discovery = hs.config.oidc_discover # type: bool
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self._user_mapping_provider = hs.config.oidc_user_mapping_provider_class(
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hs.config.oidc_user_mapping_provider_config
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) # type: OidcMappingProvider
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self._skip_verification = hs.config.oidc_skip_verification # type: bool
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self._allow_existing_users = hs.config.oidc_allow_existing_users # type: bool
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self._http_client = hs.get_proxied_http_client()
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self._auth_handler = hs.get_auth_handler()
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self._registration_handler = hs.get_registration_handler()
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self._server_name = hs.config.server_name # type: str
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self._macaroon_secret_key = hs.config.macaroon_secret_key
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# identifier for the external_ids table
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self._auth_provider_id = "oidc"
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self._sso_handler = hs.get_sso_handler()
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def _validate_metadata(self):
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"""Verifies the provider metadata.
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This checks the validity of the currently loaded provider. Not
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everything is checked, only:
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- ``issuer``
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- ``authorization_endpoint``
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- ``token_endpoint``
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- ``response_types_supported`` (checks if "code" is in it)
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- ``jwks_uri``
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Raises:
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ValueError: if something in the provider is not valid
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"""
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# Skip verification to allow non-compliant providers (e.g. issuers not running on a secure origin)
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if self._skip_verification is True:
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return
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m = self._provider_metadata
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m.validate_issuer()
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m.validate_authorization_endpoint()
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m.validate_token_endpoint()
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if m.get("token_endpoint_auth_methods_supported") is not None:
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m.validate_token_endpoint_auth_methods_supported()
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if (
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self._client_auth_method
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not in m["token_endpoint_auth_methods_supported"]
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):
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raise ValueError(
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'"{auth_method}" not in "token_endpoint_auth_methods_supported" ({supported!r})'.format(
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auth_method=self._client_auth_method,
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supported=m["token_endpoint_auth_methods_supported"],
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)
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)
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if m.get("response_types_supported") is not None:
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m.validate_response_types_supported()
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if "code" not in m["response_types_supported"]:
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raise ValueError(
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'"code" not in "response_types_supported" (%r)'
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% (m["response_types_supported"],)
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)
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# Ensure there's a userinfo endpoint to fetch from if it is required.
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if self._uses_userinfo:
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if m.get("userinfo_endpoint") is None:
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raise ValueError(
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'provider has no "userinfo_endpoint", even though it is required'
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)
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else:
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# If we're not using userinfo, we need a valid jwks to validate the ID token
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if m.get("jwks") is None:
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if m.get("jwks_uri") is not None:
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m.validate_jwks_uri()
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else:
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raise ValueError('"jwks_uri" must be set')
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@property
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def _uses_userinfo(self) -> bool:
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"""Returns True if the ``userinfo_endpoint`` should be used.
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This is based on the requested scopes: if the scopes include
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``openid``, the provider should give use an ID token containing the
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user information. If not, we should fetch them using the
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``access_token`` with the ``userinfo_endpoint``.
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"""
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return (
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"openid" not in self._scopes
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or self._user_profile_method == "userinfo_endpoint"
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)
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async def load_metadata(self) -> OpenIDProviderMetadata:
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"""Load and validate the provider metadata.
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The values metadatas are discovered if ``oidc_config.discovery`` is
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``True`` and then cached.
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Raises:
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ValueError: if something in the provider is not valid
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Returns:
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The provider's metadata.
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"""
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# If we are using the OpenID Discovery documents, it needs to be loaded once
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# FIXME: should there be a lock here?
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if self._provider_needs_discovery:
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url = get_well_known_url(self._provider_metadata["issuer"], external=True)
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metadata_response = await self._http_client.get_json(url)
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# TODO: maybe update the other way around to let user override some values?
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self._provider_metadata.update(metadata_response)
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self._provider_needs_discovery = False
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self._validate_metadata()
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return self._provider_metadata
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async def load_jwks(self, force: bool = False) -> JWKS:
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"""Load the JSON Web Key Set used to sign ID tokens.
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If we're not using the ``userinfo_endpoint``, user infos are extracted
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from the ID token, which is a JWT signed by keys given by the provider.
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The keys are then cached.
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Args:
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force: Force reloading the keys.
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Returns:
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The key set
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Looks like this::
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{
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'keys': [
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{
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'kid': 'abcdef',
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'kty': 'RSA',
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'alg': 'RS256',
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'use': 'sig',
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'e': 'XXXX',
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'n': 'XXXX',
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}
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]
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}
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"""
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if self._uses_userinfo:
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# We're not using jwt signing, return an empty jwk set
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return {"keys": []}
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# First check if the JWKS are loaded in the provider metadata.
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# It can happen either if the provider gives its JWKS in the discovery
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# document directly or if it was already loaded once.
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metadata = await self.load_metadata()
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jwk_set = metadata.get("jwks")
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if jwk_set is not None and not force:
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return jwk_set
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# Loading the JWKS using the `jwks_uri` metadata
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uri = metadata.get("jwks_uri")
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if not uri:
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raise RuntimeError('Missing "jwks_uri" in metadata')
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jwk_set = await self._http_client.get_json(uri)
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# Caching the JWKS in the provider's metadata
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self._provider_metadata["jwks"] = jwk_set
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return jwk_set
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async def _exchange_code(self, code: str) -> Token:
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"""Exchange an authorization code for a token.
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This calls the ``token_endpoint`` with the authorization code we
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received in the callback to exchange it for a token. The call uses the
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``ClientAuth`` to authenticate with the client with its ID and secret.
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See:
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https://tools.ietf.org/html/rfc6749#section-3.2
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https://openid.net/specs/openid-connect-core-1_0.html#TokenEndpoint
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Args:
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code: The authorization code we got from the callback.
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Returns:
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A dict containing various tokens.
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May look like this::
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{
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'token_type': 'bearer',
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'access_token': 'abcdef',
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'expires_in': 3599,
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'id_token': 'ghijkl',
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'refresh_token': 'mnopqr',
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}
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Raises:
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OidcError: when the ``token_endpoint`` returned an error.
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"""
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metadata = await self.load_metadata()
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token_endpoint = metadata.get("token_endpoint")
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headers = {
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"Content-Type": "application/x-www-form-urlencoded",
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"User-Agent": self._http_client.user_agent,
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"Accept": "application/json",
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}
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args = {
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"grant_type": "authorization_code",
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"code": code,
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"redirect_uri": self._callback_url,
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}
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body = urlencode(args, True)
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# Fill the body/headers with credentials
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uri, headers, body = self._client_auth.prepare(
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method="POST", uri=token_endpoint, headers=headers, body=body
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)
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headers = {k: [v] for (k, v) in headers.items()}
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# Do the actual request
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# We're not using the SimpleHttpClient util methods as we don't want to
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# check the HTTP status code and we do the body encoding ourself.
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response = await self._http_client.request(
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method="POST", uri=uri, data=body.encode("utf-8"), headers=headers,
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)
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# This is used in multiple error messages below
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status = "{code} {phrase}".format(
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code=response.code, phrase=response.phrase.decode("utf-8")
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)
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resp_body = await make_deferred_yieldable(readBody(response))
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if response.code >= 500:
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# In case of a server error, we should first try to decode the body
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# and check for an error field. If not, we respond with a generic
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# error message.
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try:
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resp = json_decoder.decode(resp_body.decode("utf-8"))
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error = resp["error"]
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description = resp.get("error_description", error)
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except (ValueError, KeyError):
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# Catch ValueError for the JSON decoding and KeyError for the "error" field
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error = "server_error"
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description = (
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(
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'Authorization server responded with a "{status}" error '
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"while exchanging the authorization code."
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).format(status=status),
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)
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raise OidcError(error, description)
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# Since it is a not a 5xx code, body should be a valid JSON. It will
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# raise if not.
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resp = json_decoder.decode(resp_body.decode("utf-8"))
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if "error" in resp:
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error = resp["error"]
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# In case the authorization server responded with an error field,
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# it should be a 4xx code. If not, warn about it but don't do
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# anything special and report the original error message.
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if response.code < 400:
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logger.debug(
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"Invalid response from the authorization server: "
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'responded with a "{status}" '
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"but body has an error field: {error!r}".format(
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status=status, error=resp["error"]
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)
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)
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description = resp.get("error_description", error)
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raise OidcError(error, description)
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# Now, this should not be an error. According to RFC6749 sec 5.1, it
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# should be a 200 code. We're a bit more flexible than that, and will
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# only throw on a 4xx code.
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if response.code >= 400:
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description = (
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'Authorization server responded with a "{status}" error '
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'but did not include an "error" field in its response.'.format(
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status=status
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)
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)
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logger.warning(description)
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# Body was still valid JSON. Might be useful to log it for debugging.
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logger.warning("Code exchange response: {resp!r}".format(resp=resp))
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raise OidcError("server_error", description)
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return resp
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async def _fetch_userinfo(self, token: Token) -> UserInfo:
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"""Fetch user information from the ``userinfo_endpoint``.
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Args:
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token: the token given by the ``token_endpoint``.
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Must include an ``access_token`` field.
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Returns:
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UserInfo: an object representing the user.
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"""
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metadata = await self.load_metadata()
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resp = await self._http_client.get_json(
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metadata["userinfo_endpoint"],
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headers={"Authorization": ["Bearer {}".format(token["access_token"])]},
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)
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return UserInfo(resp)
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async def _parse_id_token(self, token: Token, nonce: str) -> UserInfo:
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"""Return an instance of UserInfo from token's ``id_token``.
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Args:
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token: the token given by the ``token_endpoint``.
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Must include an ``id_token`` field.
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nonce: the nonce value originally sent in the initial authorization
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request. This value should match the one inside the token.
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Returns:
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An object representing the user.
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"""
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metadata = await self.load_metadata()
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claims_params = {
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"nonce": nonce,
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"client_id": self._client_auth.client_id,
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}
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if "access_token" in token:
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# If we got an `access_token`, there should be an `at_hash` claim
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# in the `id_token` that we can check against.
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claims_params["access_token"] = token["access_token"]
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claims_cls = CodeIDToken
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else:
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claims_cls = ImplicitIDToken
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alg_values = metadata.get("id_token_signing_alg_values_supported", ["RS256"])
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jwt = JsonWebToken(alg_values)
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claim_options = {"iss": {"values": [metadata["issuer"]]}}
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# Try to decode the keys in cache first, then retry by forcing the keys
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# to be reloaded
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jwk_set = await self.load_jwks()
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try:
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claims = jwt.decode(
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token["id_token"],
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key=jwk_set,
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claims_cls=claims_cls,
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claims_options=claim_options,
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claims_params=claims_params,
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)
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except ValueError:
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logger.info("Reloading JWKS after decode error")
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jwk_set = await self.load_jwks(force=True) # try reloading the jwks
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claims = jwt.decode(
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token["id_token"],
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key=jwk_set,
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claims_cls=claims_cls,
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claims_options=claim_options,
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claims_params=claims_params,
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)
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claims.validate(leeway=120) # allows 2 min of clock skew
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return UserInfo(claims)
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async def handle_redirect_request(
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self,
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request: SynapseRequest,
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client_redirect_url: bytes,
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ui_auth_session_id: Optional[str] = None,
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) -> str:
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"""Handle an incoming request to /login/sso/redirect
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It returns a redirect to the authorization endpoint with a few
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parameters:
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- ``client_id``: the client ID set in ``oidc_config.client_id``
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- ``response_type``: ``code``
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- ``redirect_uri``: the callback URL ; ``{base url}/_synapse/oidc/callback``
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- ``scope``: the list of scopes set in ``oidc_config.scopes``
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- ``state``: a random string
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- ``nonce``: a random string
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In addition generating a redirect URL, we are setting a cookie with
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a signed macaroon token containing the state, the nonce and the
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client_redirect_url params. Those are then checked when the client
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comes back from the provider.
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Args:
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request: the incoming request from the browser.
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We'll respond to it with a redirect and a cookie.
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client_redirect_url: the URL that we should redirect the client to
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when everything is done
|
|
ui_auth_session_id: The session ID of the ongoing UI Auth (or
|
|
None if this is a login).
|
|
|
|
Returns:
|
|
The redirect URL to the authorization endpoint.
|
|
|
|
"""
|
|
|
|
state = generate_token()
|
|
nonce = generate_token()
|
|
|
|
cookie = self._generate_oidc_session_token(
|
|
state=state,
|
|
nonce=nonce,
|
|
client_redirect_url=client_redirect_url.decode(),
|
|
ui_auth_session_id=ui_auth_session_id,
|
|
)
|
|
request.addCookie(
|
|
SESSION_COOKIE_NAME,
|
|
cookie,
|
|
path="/_synapse/oidc",
|
|
max_age="3600",
|
|
httpOnly=True,
|
|
sameSite="lax",
|
|
)
|
|
|
|
metadata = await self.load_metadata()
|
|
authorization_endpoint = metadata.get("authorization_endpoint")
|
|
return prepare_grant_uri(
|
|
authorization_endpoint,
|
|
client_id=self._client_auth.client_id,
|
|
response_type="code",
|
|
redirect_uri=self._callback_url,
|
|
scope=self._scopes,
|
|
state=state,
|
|
nonce=nonce,
|
|
)
|
|
|
|
async def handle_oidc_callback(self, request: SynapseRequest) -> None:
|
|
"""Handle an incoming request to /_synapse/oidc/callback
|
|
|
|
Since we might want to display OIDC-related errors in a user-friendly
|
|
way, we don't raise SynapseError from here. Instead, we call
|
|
``self._sso_handler.render_error`` which displays an HTML page for the error.
|
|
|
|
Most of the OpenID Connect logic happens here:
|
|
|
|
- first, we check if there was any error returned by the provider and
|
|
display it
|
|
- then we fetch the session cookie, decode and verify it
|
|
- the ``state`` query parameter should match with the one stored in the
|
|
session cookie
|
|
- once we known this session is legit, exchange the code with the
|
|
provider using the ``token_endpoint`` (see ``_exchange_code``)
|
|
- once we have the token, use it to either extract the UserInfo from
|
|
the ``id_token`` (``_parse_id_token``), or use the ``access_token``
|
|
to fetch UserInfo from the ``userinfo_endpoint``
|
|
(``_fetch_userinfo``)
|
|
- map those UserInfo to a Matrix user (``_map_userinfo_to_user``) and
|
|
finish the login
|
|
|
|
Args:
|
|
request: the incoming request from the browser.
|
|
"""
|
|
|
|
# The provider might redirect with an error.
|
|
# In that case, just display it as-is.
|
|
if b"error" in request.args:
|
|
# error response from the auth server. see:
|
|
# https://tools.ietf.org/html/rfc6749#section-4.1.2.1
|
|
# https://openid.net/specs/openid-connect-core-1_0.html#AuthError
|
|
error = request.args[b"error"][0].decode()
|
|
description = request.args.get(b"error_description", [b""])[0].decode()
|
|
|
|
# Most of the errors returned by the provider could be due by
|
|
# either the provider misbehaving or Synapse being misconfigured.
|
|
# The only exception of that is "access_denied", where the user
|
|
# probably cancelled the login flow. In other cases, log those errors.
|
|
if error != "access_denied":
|
|
logger.error("Error from the OIDC provider: %s %s", error, description)
|
|
|
|
self._sso_handler.render_error(request, error, description)
|
|
return
|
|
|
|
# otherwise, it is presumably a successful response. see:
|
|
# https://tools.ietf.org/html/rfc6749#section-4.1.2
|
|
|
|
# Fetch the session cookie
|
|
session = request.getCookie(SESSION_COOKIE_NAME) # type: Optional[bytes]
|
|
if session is None:
|
|
logger.info("No session cookie found")
|
|
self._sso_handler.render_error(
|
|
request, "missing_session", "No session cookie found"
|
|
)
|
|
return
|
|
|
|
# Remove the cookie. There is a good chance that if the callback failed
|
|
# once, it will fail next time and the code will already be exchanged.
|
|
# Removing it early avoids spamming the provider with token requests.
|
|
request.addCookie(
|
|
SESSION_COOKIE_NAME,
|
|
b"",
|
|
path="/_synapse/oidc",
|
|
expires="Thu, Jan 01 1970 00:00:00 UTC",
|
|
httpOnly=True,
|
|
sameSite="lax",
|
|
)
|
|
|
|
# Check for the state query parameter
|
|
if b"state" not in request.args:
|
|
logger.info("State parameter is missing")
|
|
self._sso_handler.render_error(
|
|
request, "invalid_request", "State parameter is missing"
|
|
)
|
|
return
|
|
|
|
state = request.args[b"state"][0].decode()
|
|
|
|
# Deserialize the session token and verify it.
|
|
try:
|
|
(
|
|
nonce,
|
|
client_redirect_url,
|
|
ui_auth_session_id,
|
|
) = self._verify_oidc_session_token(session, state)
|
|
except MacaroonDeserializationException as e:
|
|
logger.exception("Invalid session")
|
|
self._sso_handler.render_error(request, "invalid_session", str(e))
|
|
return
|
|
except MacaroonInvalidSignatureException as e:
|
|
logger.exception("Could not verify session")
|
|
self._sso_handler.render_error(request, "mismatching_session", str(e))
|
|
return
|
|
|
|
# Exchange the code with the provider
|
|
if b"code" not in request.args:
|
|
logger.info("Code parameter is missing")
|
|
self._sso_handler.render_error(
|
|
request, "invalid_request", "Code parameter is missing"
|
|
)
|
|
return
|
|
|
|
logger.debug("Exchanging code")
|
|
code = request.args[b"code"][0].decode()
|
|
try:
|
|
token = await self._exchange_code(code)
|
|
except OidcError as e:
|
|
logger.exception("Could not exchange code")
|
|
self._sso_handler.render_error(request, e.error, e.error_description)
|
|
return
|
|
|
|
logger.debug("Successfully obtained OAuth2 access token")
|
|
|
|
# Now that we have a token, get the userinfo, either by decoding the
|
|
# `id_token` or by fetching the `userinfo_endpoint`.
|
|
if self._uses_userinfo:
|
|
logger.debug("Fetching userinfo")
|
|
try:
|
|
userinfo = await self._fetch_userinfo(token)
|
|
except Exception as e:
|
|
logger.exception("Could not fetch userinfo")
|
|
self._sso_handler.render_error(request, "fetch_error", str(e))
|
|
return
|
|
else:
|
|
logger.debug("Extracting userinfo from id_token")
|
|
try:
|
|
userinfo = await self._parse_id_token(token, nonce=nonce)
|
|
except Exception as e:
|
|
logger.exception("Invalid id_token")
|
|
self._sso_handler.render_error(request, "invalid_token", str(e))
|
|
return
|
|
|
|
# first check if we're doing a UIA
|
|
if ui_auth_session_id:
|
|
try:
|
|
remote_user_id = self._remote_id_from_userinfo(userinfo)
|
|
except Exception as e:
|
|
logger.exception("Could not extract remote user id")
|
|
self._sso_handler.render_error(request, "mapping_error", str(e))
|
|
return
|
|
|
|
return await self._sso_handler.complete_sso_ui_auth_request(
|
|
self._auth_provider_id, remote_user_id, ui_auth_session_id, request
|
|
)
|
|
|
|
# otherwise, it's a login
|
|
|
|
# Pull out the user-agent and IP from the request.
|
|
user_agent = request.get_user_agent("")
|
|
ip_address = self.hs.get_ip_from_request(request)
|
|
|
|
# Call the mapper to register/login the user
|
|
try:
|
|
user_id = await self._map_userinfo_to_user(
|
|
userinfo, token, user_agent, ip_address
|
|
)
|
|
except MappingException as e:
|
|
logger.exception("Could not map user")
|
|
self._sso_handler.render_error(request, "mapping_error", str(e))
|
|
return
|
|
|
|
# Mapping providers might not have get_extra_attributes: only call this
|
|
# method if it exists.
|
|
extra_attributes = None
|
|
get_extra_attributes = getattr(
|
|
self._user_mapping_provider, "get_extra_attributes", None
|
|
)
|
|
if get_extra_attributes:
|
|
extra_attributes = await get_extra_attributes(userinfo, token)
|
|
|
|
# and finally complete the login
|
|
await self._auth_handler.complete_sso_login(
|
|
user_id, request, client_redirect_url, extra_attributes
|
|
)
|
|
|
|
def _generate_oidc_session_token(
|
|
self,
|
|
state: str,
|
|
nonce: str,
|
|
client_redirect_url: str,
|
|
ui_auth_session_id: Optional[str],
|
|
duration_in_ms: int = (60 * 60 * 1000),
|
|
) -> str:
|
|
"""Generates a signed token storing data about an OIDC session.
|
|
|
|
When Synapse initiates an authorization flow, it creates a random state
|
|
and a random nonce. Those parameters are given to the provider and
|
|
should be verified when the client comes back from the provider.
|
|
It is also used to store the client_redirect_url, which is used to
|
|
complete the SSO login flow.
|
|
|
|
Args:
|
|
state: The ``state`` parameter passed to the OIDC provider.
|
|
nonce: The ``nonce`` parameter passed to the OIDC provider.
|
|
client_redirect_url: The URL the client gave when it initiated the
|
|
flow.
|
|
ui_auth_session_id: The session ID of the ongoing UI Auth (or
|
|
None if this is a login).
|
|
duration_in_ms: An optional duration for the token in milliseconds.
|
|
Defaults to an hour.
|
|
|
|
Returns:
|
|
A signed macaroon token with the session information.
|
|
"""
|
|
macaroon = pymacaroons.Macaroon(
|
|
location=self._server_name, identifier="key", key=self._macaroon_secret_key,
|
|
)
|
|
macaroon.add_first_party_caveat("gen = 1")
|
|
macaroon.add_first_party_caveat("type = session")
|
|
macaroon.add_first_party_caveat("state = %s" % (state,))
|
|
macaroon.add_first_party_caveat("nonce = %s" % (nonce,))
|
|
macaroon.add_first_party_caveat(
|
|
"client_redirect_url = %s" % (client_redirect_url,)
|
|
)
|
|
if ui_auth_session_id:
|
|
macaroon.add_first_party_caveat(
|
|
"ui_auth_session_id = %s" % (ui_auth_session_id,)
|
|
)
|
|
now = self.clock.time_msec()
|
|
expiry = now + duration_in_ms
|
|
macaroon.add_first_party_caveat("time < %d" % (expiry,))
|
|
|
|
return macaroon.serialize()
|
|
|
|
def _verify_oidc_session_token(
|
|
self, session: bytes, state: str
|
|
) -> Tuple[str, str, Optional[str]]:
|
|
"""Verifies and extract an OIDC session token.
|
|
|
|
This verifies that a given session token was issued by this homeserver
|
|
and extract the nonce and client_redirect_url caveats.
|
|
|
|
Args:
|
|
session: The session token to verify
|
|
state: The state the OIDC provider gave back
|
|
|
|
Returns:
|
|
The nonce, client_redirect_url, and ui_auth_session_id for this session
|
|
"""
|
|
macaroon = pymacaroons.Macaroon.deserialize(session)
|
|
|
|
v = pymacaroons.Verifier()
|
|
v.satisfy_exact("gen = 1")
|
|
v.satisfy_exact("type = session")
|
|
v.satisfy_exact("state = %s" % (state,))
|
|
v.satisfy_general(lambda c: c.startswith("nonce = "))
|
|
v.satisfy_general(lambda c: c.startswith("client_redirect_url = "))
|
|
# Sometimes there's a UI auth session ID, it seems to be OK to attempt
|
|
# to always satisfy this.
|
|
v.satisfy_general(lambda c: c.startswith("ui_auth_session_id = "))
|
|
v.satisfy_general(self._verify_expiry)
|
|
|
|
v.verify(macaroon, self._macaroon_secret_key)
|
|
|
|
# Extract the `nonce`, `client_redirect_url`, and maybe the
|
|
# `ui_auth_session_id` from the token.
|
|
nonce = self._get_value_from_macaroon(macaroon, "nonce")
|
|
client_redirect_url = self._get_value_from_macaroon(
|
|
macaroon, "client_redirect_url"
|
|
)
|
|
try:
|
|
ui_auth_session_id = self._get_value_from_macaroon(
|
|
macaroon, "ui_auth_session_id"
|
|
) # type: Optional[str]
|
|
except ValueError:
|
|
ui_auth_session_id = None
|
|
|
|
return nonce, client_redirect_url, ui_auth_session_id
|
|
|
|
def _get_value_from_macaroon(self, macaroon: pymacaroons.Macaroon, key: str) -> str:
|
|
"""Extracts a caveat value from a macaroon token.
|
|
|
|
Args:
|
|
macaroon: the token
|
|
key: the key of the caveat to extract
|
|
|
|
Returns:
|
|
The extracted value
|
|
|
|
Raises:
|
|
Exception: if the caveat was not in the macaroon
|
|
"""
|
|
prefix = key + " = "
|
|
for caveat in macaroon.caveats:
|
|
if caveat.caveat_id.startswith(prefix):
|
|
return caveat.caveat_id[len(prefix) :]
|
|
raise ValueError("No %s caveat in macaroon" % (key,))
|
|
|
|
def _verify_expiry(self, caveat: str) -> bool:
|
|
prefix = "time < "
|
|
if not caveat.startswith(prefix):
|
|
return False
|
|
expiry = int(caveat[len(prefix) :])
|
|
now = self.clock.time_msec()
|
|
return now < expiry
|
|
|
|
async def _map_userinfo_to_user(
|
|
self, userinfo: UserInfo, token: Token, user_agent: str, ip_address: str
|
|
) -> str:
|
|
"""Maps a UserInfo object to a mxid.
|
|
|
|
UserInfo should have a claim that uniquely identifies users. This claim
|
|
is usually `sub`, but can be configured with `oidc_config.subject_claim`.
|
|
It is then used as an `external_id`.
|
|
|
|
If we don't find the user that way, we should register the user,
|
|
mapping the localpart and the display name from the UserInfo.
|
|
|
|
If a user already exists with the mxid we've mapped and allow_existing_users
|
|
is disabled, raise an exception.
|
|
|
|
Args:
|
|
userinfo: an object representing the user
|
|
token: a dict with the tokens obtained from the provider
|
|
user_agent: The user agent of the client making the request.
|
|
ip_address: The IP address of the client making the request.
|
|
|
|
Raises:
|
|
MappingException: if there was an error while mapping some properties
|
|
|
|
Returns:
|
|
The mxid of the user
|
|
"""
|
|
try:
|
|
remote_user_id = self._remote_id_from_userinfo(userinfo)
|
|
except Exception as e:
|
|
raise MappingException(
|
|
"Failed to extract subject from OIDC response: %s" % (e,)
|
|
)
|
|
|
|
# Older mapping providers don't accept the `failures` argument, so we
|
|
# try and detect support.
|
|
mapper_signature = inspect.signature(
|
|
self._user_mapping_provider.map_user_attributes
|
|
)
|
|
supports_failures = "failures" in mapper_signature.parameters
|
|
|
|
async def oidc_response_to_user_attributes(failures: int) -> UserAttributes:
|
|
"""
|
|
Call the mapping provider to map the OIDC userinfo and token to user attributes.
|
|
|
|
This is backwards compatibility for abstraction for the SSO handler.
|
|
"""
|
|
if supports_failures:
|
|
attributes = await self._user_mapping_provider.map_user_attributes(
|
|
userinfo, token, failures
|
|
)
|
|
else:
|
|
# If the mapping provider does not support processing failures,
|
|
# do not continually generate the same Matrix ID since it will
|
|
# continue to already be in use. Note that the error raised is
|
|
# arbitrary and will get turned into a MappingException.
|
|
if failures:
|
|
raise MappingException(
|
|
"Mapping provider does not support de-duplicating Matrix IDs"
|
|
)
|
|
|
|
attributes = await self._user_mapping_provider.map_user_attributes( # type: ignore
|
|
userinfo, token
|
|
)
|
|
|
|
return UserAttributes(**attributes)
|
|
|
|
async def grandfather_existing_users() -> Optional[str]:
|
|
if self._allow_existing_users:
|
|
# If allowing existing users we want to generate a single localpart
|
|
# and attempt to match it.
|
|
attributes = await oidc_response_to_user_attributes(failures=0)
|
|
|
|
user_id = UserID(attributes.localpart, self.server_name).to_string()
|
|
users = await self.store.get_users_by_id_case_insensitive(user_id)
|
|
if users:
|
|
# If an existing matrix ID is returned, then use it.
|
|
if len(users) == 1:
|
|
previously_registered_user_id = next(iter(users))
|
|
elif user_id in users:
|
|
previously_registered_user_id = user_id
|
|
else:
|
|
# Do not attempt to continue generating Matrix IDs.
|
|
raise MappingException(
|
|
"Attempted to login as '{}' but it matches more than one user inexactly: {}".format(
|
|
user_id, users
|
|
)
|
|
)
|
|
|
|
return previously_registered_user_id
|
|
|
|
return None
|
|
|
|
return await self._sso_handler.get_mxid_from_sso(
|
|
self._auth_provider_id,
|
|
remote_user_id,
|
|
user_agent,
|
|
ip_address,
|
|
oidc_response_to_user_attributes,
|
|
grandfather_existing_users,
|
|
)
|
|
|
|
def _remote_id_from_userinfo(self, userinfo: UserInfo) -> str:
|
|
"""Extract the unique remote id from an OIDC UserInfo block
|
|
|
|
Args:
|
|
userinfo: An object representing the user given by the OIDC provider
|
|
Returns:
|
|
remote user id
|
|
"""
|
|
remote_user_id = self._user_mapping_provider.get_remote_user_id(userinfo)
|
|
# Some OIDC providers use integer IDs, but Synapse expects external IDs
|
|
# to be strings.
|
|
return str(remote_user_id)
|
|
|
|
|
|
UserAttributeDict = TypedDict(
|
|
"UserAttributeDict", {"localpart": str, "display_name": Optional[str]}
|
|
)
|
|
C = TypeVar("C")
|
|
|
|
|
|
class OidcMappingProvider(Generic[C]):
|
|
"""A mapping provider maps a UserInfo object to user attributes.
|
|
|
|
It should provide the API described by this class.
|
|
"""
|
|
|
|
def __init__(self, config: C):
|
|
"""
|
|
Args:
|
|
config: A custom config object from this module, parsed by ``parse_config()``
|
|
"""
|
|
|
|
@staticmethod
|
|
def parse_config(config: dict) -> C:
|
|
"""Parse the dict provided by the homeserver's config
|
|
|
|
Args:
|
|
config: A dictionary containing configuration options for this provider
|
|
|
|
Returns:
|
|
A custom config object for this module
|
|
"""
|
|
raise NotImplementedError()
|
|
|
|
def get_remote_user_id(self, userinfo: UserInfo) -> str:
|
|
"""Get a unique user ID for this user.
|
|
|
|
Usually, in an OIDC-compliant scenario, it should be the ``sub`` claim from the UserInfo object.
|
|
|
|
Args:
|
|
userinfo: An object representing the user given by the OIDC provider
|
|
|
|
Returns:
|
|
A unique user ID
|
|
"""
|
|
raise NotImplementedError()
|
|
|
|
async def map_user_attributes(
|
|
self, userinfo: UserInfo, token: Token, failures: int
|
|
) -> UserAttributeDict:
|
|
"""Map a `UserInfo` object into user attributes.
|
|
|
|
Args:
|
|
userinfo: An object representing the user given by the OIDC provider
|
|
token: A dict with the tokens returned by the provider
|
|
failures: How many times a call to this function with this
|
|
UserInfo has resulted in a failure.
|
|
|
|
Returns:
|
|
A dict containing the ``localpart`` and (optionally) the ``display_name``
|
|
"""
|
|
raise NotImplementedError()
|
|
|
|
async def get_extra_attributes(self, userinfo: UserInfo, token: Token) -> JsonDict:
|
|
"""Map a `UserInfo` object into additional attributes passed to the client during login.
|
|
|
|
Args:
|
|
userinfo: An object representing the user given by the OIDC provider
|
|
token: A dict with the tokens returned by the provider
|
|
|
|
Returns:
|
|
A dict containing additional attributes. Must be JSON serializable.
|
|
"""
|
|
return {}
|
|
|
|
|
|
# Used to clear out "None" values in templates
|
|
def jinja_finalize(thing):
|
|
return thing if thing is not None else ""
|
|
|
|
|
|
env = Environment(finalize=jinja_finalize)
|
|
|
|
|
|
@attr.s
|
|
class JinjaOidcMappingConfig:
|
|
subject_claim = attr.ib() # type: str
|
|
localpart_template = attr.ib() # type: Template
|
|
display_name_template = attr.ib() # type: Optional[Template]
|
|
extra_attributes = attr.ib() # type: Dict[str, Template]
|
|
|
|
|
|
class JinjaOidcMappingProvider(OidcMappingProvider[JinjaOidcMappingConfig]):
|
|
"""An implementation of a mapping provider based on Jinja templates.
|
|
|
|
This is the default mapping provider.
|
|
"""
|
|
|
|
def __init__(self, config: JinjaOidcMappingConfig):
|
|
self._config = config
|
|
|
|
@staticmethod
|
|
def parse_config(config: dict) -> JinjaOidcMappingConfig:
|
|
subject_claim = config.get("subject_claim", "sub")
|
|
|
|
if "localpart_template" not in config:
|
|
raise ConfigError(
|
|
"missing key: oidc_config.user_mapping_provider.config.localpart_template"
|
|
)
|
|
|
|
try:
|
|
localpart_template = env.from_string(config["localpart_template"])
|
|
except Exception as e:
|
|
raise ConfigError(
|
|
"invalid jinja template for oidc_config.user_mapping_provider.config.localpart_template: %r"
|
|
% (e,)
|
|
)
|
|
|
|
display_name_template = None # type: Optional[Template]
|
|
if "display_name_template" in config:
|
|
try:
|
|
display_name_template = env.from_string(config["display_name_template"])
|
|
except Exception as e:
|
|
raise ConfigError(
|
|
"invalid jinja template for oidc_config.user_mapping_provider.config.display_name_template: %r"
|
|
% (e,)
|
|
)
|
|
|
|
extra_attributes = {} # type Dict[str, Template]
|
|
if "extra_attributes" in config:
|
|
extra_attributes_config = config.get("extra_attributes") or {}
|
|
if not isinstance(extra_attributes_config, dict):
|
|
raise ConfigError(
|
|
"oidc_config.user_mapping_provider.config.extra_attributes must be a dict"
|
|
)
|
|
|
|
for key, value in extra_attributes_config.items():
|
|
try:
|
|
extra_attributes[key] = env.from_string(value)
|
|
except Exception as e:
|
|
raise ConfigError(
|
|
"invalid jinja template for oidc_config.user_mapping_provider.config.extra_attributes.%s: %r"
|
|
% (key, e)
|
|
)
|
|
|
|
return JinjaOidcMappingConfig(
|
|
subject_claim=subject_claim,
|
|
localpart_template=localpart_template,
|
|
display_name_template=display_name_template,
|
|
extra_attributes=extra_attributes,
|
|
)
|
|
|
|
def get_remote_user_id(self, userinfo: UserInfo) -> str:
|
|
return userinfo[self._config.subject_claim]
|
|
|
|
async def map_user_attributes(
|
|
self, userinfo: UserInfo, token: Token, failures: int
|
|
) -> UserAttributeDict:
|
|
localpart = self._config.localpart_template.render(user=userinfo).strip()
|
|
|
|
# Ensure only valid characters are included in the MXID.
|
|
localpart = map_username_to_mxid_localpart(localpart)
|
|
|
|
# Append suffix integer if last call to this function failed to produce
|
|
# a usable mxid.
|
|
localpart += str(failures) if failures else ""
|
|
|
|
display_name = None # type: Optional[str]
|
|
if self._config.display_name_template is not None:
|
|
display_name = self._config.display_name_template.render(
|
|
user=userinfo
|
|
).strip()
|
|
|
|
if display_name == "":
|
|
display_name = None
|
|
|
|
return UserAttributeDict(localpart=localpart, display_name=display_name)
|
|
|
|
async def get_extra_attributes(self, userinfo: UserInfo, token: Token) -> JsonDict:
|
|
extras = {} # type: Dict[str, str]
|
|
for key, template in self._config.extra_attributes.items():
|
|
try:
|
|
extras[key] = template.render(user=userinfo).strip()
|
|
except Exception as e:
|
|
# Log an error and skip this value (don't break login for this).
|
|
logger.error("Failed to render OIDC extra attribute %s: %s" % (key, e))
|
|
return extras
|