264 lines
11 KiB
Python
264 lines
11 KiB
Python
# Copyright 2023 The Matrix.org Foundation.
|
|
#
|
|
# 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, Any, Dict, List, Optional
|
|
from urllib.parse import urlencode
|
|
|
|
from authlib.oauth2 import ClientAuth
|
|
from authlib.oauth2.auth import encode_client_secret_basic, encode_client_secret_post
|
|
from authlib.oauth2.rfc7523 import ClientSecretJWT, PrivateKeyJWT, private_key_jwt_sign
|
|
from authlib.oauth2.rfc7662 import IntrospectionToken
|
|
from authlib.oidc.discovery import OpenIDProviderMetadata, get_well_known_url
|
|
|
|
from twisted.web.client import readBody
|
|
from twisted.web.http_headers import Headers
|
|
|
|
from synapse.api.auth.base import BaseAuth
|
|
from synapse.api.errors import AuthError, InvalidClientTokenError, StoreError
|
|
from synapse.http.site import SynapseRequest
|
|
from synapse.logging.context import make_deferred_yieldable
|
|
from synapse.types import Requester, UserID, create_requester
|
|
from synapse.util import json_decoder
|
|
from synapse.util.caches.cached_call import RetryOnExceptionCachedCall
|
|
|
|
if TYPE_CHECKING:
|
|
from synapse.server import HomeServer
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
def scope_to_list(scope: str) -> List[str]:
|
|
"""Convert a scope string to a list of scope tokens"""
|
|
return scope.strip().split(" ")
|
|
|
|
|
|
class PrivateKeyJWTWithKid(PrivateKeyJWT):
|
|
"""An implementation of the private_key_jwt client auth method that includes a kid header.
|
|
|
|
This is needed because some providers (Keycloak) require the kid header to figure
|
|
out which key to use to verify the signature.
|
|
"""
|
|
|
|
def sign(self, auth: Any, token_endpoint: str) -> bytes:
|
|
return private_key_jwt_sign(
|
|
auth.client_secret,
|
|
client_id=auth.client_id,
|
|
token_endpoint=token_endpoint,
|
|
claims=self.claims,
|
|
header={"kid": auth.client_secret["kid"]},
|
|
)
|
|
|
|
|
|
class OAuthDelegatedAuth(BaseAuth):
|
|
AUTH_METHODS = {
|
|
"client_secret_post": encode_client_secret_post,
|
|
"client_secret_basic": encode_client_secret_basic,
|
|
"client_secret_jwt": ClientSecretJWT(),
|
|
"private_key_jwt": PrivateKeyJWTWithKid(),
|
|
}
|
|
|
|
EXTERNAL_ID_PROVIDER = "oauth-delegated"
|
|
|
|
def __init__(self, hs: "HomeServer"):
|
|
super().__init__(hs)
|
|
|
|
self._config = hs.config.auth
|
|
assert self._config.oauth_delegation_enabled, "OAuth delegation is not enabled"
|
|
assert self._config.oauth_delegation_issuer, "No issuer provided"
|
|
assert self._config.oauth_delegation_client_id, "No client_id provided"
|
|
assert self._config.oauth_delegation_client_secret, "No client_secret provided"
|
|
assert (
|
|
self._config.oauth_delegation_client_auth_method
|
|
in OAuthDelegatedAuth.AUTH_METHODS
|
|
), "Invalid client_auth_method"
|
|
|
|
self._http_client = hs.get_proxied_http_client()
|
|
self._hostname = hs.hostname
|
|
|
|
self._issuer_metadata = RetryOnExceptionCachedCall(self._load_metadata)
|
|
secret = self._config.oauth_delegation_client_secret
|
|
self._client_auth = ClientAuth(
|
|
self._config.oauth_delegation_client_id,
|
|
secret,
|
|
OAuthDelegatedAuth.AUTH_METHODS[
|
|
self._config.oauth_delegation_client_auth_method
|
|
],
|
|
)
|
|
|
|
async def _load_metadata(self) -> OpenIDProviderMetadata:
|
|
if self._config.oauth_delegation_issuer_metadata is not None:
|
|
return OpenIDProviderMetadata(
|
|
**self._config.oauth_delegation_issuer_metadata
|
|
)
|
|
url = get_well_known_url(self._config.oauth_delegation_issuer, external=True)
|
|
response = await self._http_client.get_json(url)
|
|
metadata = OpenIDProviderMetadata(**response)
|
|
# metadata.validate_introspection_endpoint()
|
|
return metadata
|
|
|
|
async def _introspect_token(self, token: str) -> IntrospectionToken:
|
|
metadata = await self._issuer_metadata.get()
|
|
introspection_endpoint = metadata.get("introspection_endpoint")
|
|
raw_headers: Dict[str, str] = {
|
|
"Content-Type": "application/x-www-form-urlencoded",
|
|
"User-Agent": str(self._http_client.user_agent, "utf-8"),
|
|
"Accept": "application/json",
|
|
}
|
|
|
|
args = {"token": token, "token_type_hint": "access_token"}
|
|
body = urlencode(args, True)
|
|
|
|
# Fill the body/headers with credentials
|
|
uri, raw_headers, body = self._client_auth.prepare(
|
|
method="POST", uri=introspection_endpoint, headers=raw_headers, body=body
|
|
)
|
|
headers = Headers({k: [v] for (k, v) in raw_headers.items()})
|
|
|
|
# Do the actual request
|
|
# We're not using the SimpleHttpClient util methods as we don't want to
|
|
# check the HTTP status code and we do the body encoding ourself.
|
|
response = await self._http_client.request(
|
|
method="POST",
|
|
uri=uri,
|
|
data=body.encode("utf-8"),
|
|
headers=headers,
|
|
)
|
|
|
|
resp_body = await make_deferred_yieldable(readBody(response))
|
|
# TODO: Let's not worry about 5xx errors & co. for now and just try
|
|
# decoding that as JSON. We should also do some validation of the
|
|
# response
|
|
resp = json_decoder.decode(resp_body.decode("utf-8"))
|
|
return IntrospectionToken(**resp)
|
|
|
|
async def is_server_admin(self, requester: Requester) -> bool:
|
|
return "urn:synapse:admin:*" in requester.scope
|
|
|
|
async def get_user_by_req(
|
|
self,
|
|
request: SynapseRequest,
|
|
allow_guest: bool = False,
|
|
allow_expired: bool = False,
|
|
) -> Requester:
|
|
access_token = self.get_access_token_from_request(request)
|
|
return await self.get_user_by_access_token(access_token, allow_expired)
|
|
|
|
async def get_user_by_access_token(
|
|
self,
|
|
token: str,
|
|
allow_expired: bool = False,
|
|
) -> Requester:
|
|
introspection_result = await self._introspect_token(token)
|
|
|
|
logger.info(f"Introspection result: {introspection_result!r}")
|
|
|
|
# TODO: introspection verification should be more extensive, especially:
|
|
# - verify the audience
|
|
if not introspection_result.get("active"):
|
|
raise InvalidClientTokenError("Token is not active")
|
|
|
|
# Let's look at the scope
|
|
scope: List[str] = scope_to_list(introspection_result.get("scope", ""))
|
|
|
|
# Determine type of user based on presence of particular scopes
|
|
has_admin_scope = "urn:synapse:admin:*" in scope
|
|
has_user_scope = "urn:matrix:org.matrix.msc2967.client:api:*" in scope
|
|
has_guest_scope = "urn:matrix:org.matrix.msc2967.client:api:guest" in scope
|
|
is_user = has_user_scope or has_admin_scope
|
|
is_guest = has_guest_scope and not is_user
|
|
|
|
if not is_user and not is_guest:
|
|
raise InvalidClientTokenError("No scope in token granting user rights")
|
|
|
|
# Match via the sub claim
|
|
sub: Optional[str] = introspection_result.get("sub")
|
|
if sub is None:
|
|
raise InvalidClientTokenError(
|
|
"Invalid sub claim in the introspection result"
|
|
)
|
|
|
|
user_id_str = await self.store.get_user_by_external_id(
|
|
OAuthDelegatedAuth.EXTERNAL_ID_PROVIDER, sub
|
|
)
|
|
if user_id_str is None:
|
|
# If we could not find a user via the external_id, it either does not exist,
|
|
# or the external_id was never recorded
|
|
|
|
# TODO: claim mapping should be configurable
|
|
username: Optional[str] = introspection_result.get("username")
|
|
if username is None or not isinstance(username, str):
|
|
raise AuthError(
|
|
500,
|
|
"Invalid username claim in the introspection result",
|
|
)
|
|
user_id = UserID(username, self._hostname)
|
|
|
|
# First try to find a user from the username claim
|
|
user_info = await self.store.get_userinfo_by_id(user_id=user_id.to_string())
|
|
if user_info is None:
|
|
# If the user does not exist, we should create it on the fly
|
|
# TODO: we could use SCIM to provision users ahead of time and listen
|
|
# for SCIM SET events if those ever become standard:
|
|
# https://datatracker.ietf.org/doc/html/draft-hunt-scim-notify-00
|
|
|
|
# TODO: claim mapping should be configurable
|
|
# If present, use the name claim as the displayname
|
|
name: Optional[str] = introspection_result.get("name")
|
|
|
|
await self.store.register_user(
|
|
user_id=user_id.to_string(), create_profile_with_displayname=name
|
|
)
|
|
|
|
# And record the sub as external_id
|
|
await self.store.record_user_external_id(
|
|
OAuthDelegatedAuth.EXTERNAL_ID_PROVIDER, sub, user_id.to_string()
|
|
)
|
|
else:
|
|
user_id = UserID.from_string(user_id_str)
|
|
|
|
# Find device_id in scope
|
|
device_id = None
|
|
for tok in scope:
|
|
if tok.startswith("urn:matrix:org.matrix.msc2967.client:device:"):
|
|
parts = tok.split(":")
|
|
if len(parts) == 5:
|
|
device_id = parts[4]
|
|
|
|
if device_id:
|
|
# Create the device on the fly if it does not exist
|
|
try:
|
|
await self.store.get_device(
|
|
user_id=user_id.to_string(), device_id=device_id
|
|
)
|
|
except StoreError:
|
|
await self.store.store_device(
|
|
user_id=user_id.to_string(),
|
|
device_id=device_id,
|
|
initial_device_display_name="OIDC-native client",
|
|
)
|
|
|
|
# TODO: there is a few things missing in the requester here, which still need
|
|
# to be figured out, like:
|
|
# - impersonation, with the `authenticated_entity`, which is used for
|
|
# rate-limiting, MAU limits, etc.
|
|
# - shadow-banning, with the `shadow_banned` flag
|
|
# - a proper solution for appservices, which still needs to be figured out in
|
|
# the context of MSC3861
|
|
return create_requester(
|
|
user_id=user_id,
|
|
device_id=device_id,
|
|
scope=scope,
|
|
is_guest=is_guest,
|
|
)
|