diff --git a/synapse/handlers/oidc_handler.py b/synapse/handlers/oidc_handler.py
deleted file mode 100644
index b156196a70..0000000000
--- a/synapse/handlers/oidc_handler.py
+++ /dev/null
@@ -1,1387 +0,0 @@
-# Copyright 2020 Quentin Gliech
-# Copyright 2021 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 inspect
-import logging
-from typing import TYPE_CHECKING, Dict, Generic, List, Optional, TypeVar, Union
-from urllib.parse import urlencode
-
-import attr
-import pymacaroons
-from authlib.common.security import generate_token
-from authlib.jose import JsonWebToken, jwt
-from authlib.oauth2.auth import ClientAuth
-from authlib.oauth2.rfc6749.parameters import prepare_grant_uri
-from authlib.oidc.core import CodeIDToken, ImplicitIDToken, UserInfo
-from authlib.oidc.discovery import OpenIDProviderMetadata, get_well_known_url
-from jinja2 import Environment, Template
-from pymacaroons.exceptions import (
- MacaroonDeserializationException,
- MacaroonInitException,
- MacaroonInvalidSignatureException,
-)
-from typing_extensions import TypedDict
-
-from twisted.web.client import readBody
-from twisted.web.http_headers import Headers
-
-from synapse.config import ConfigError
-from synapse.config.oidc_config import (
- OidcProviderClientSecretJwtKey,
- OidcProviderConfig,
-)
-from synapse.handlers.sso import MappingException, UserAttributes
-from synapse.http.site import SynapseRequest
-from synapse.logging.context import make_deferred_yieldable
-from synapse.types import JsonDict, UserID, map_username_to_mxid_localpart
-from synapse.util import Clock, json_decoder
-from synapse.util.caches.cached_call import RetryOnExceptionCachedCall
-from synapse.util.macaroons import get_value_from_macaroon, satisfy_expiry
-
-if TYPE_CHECKING:
- from synapse.server import HomeServer
-
-logger = logging.getLogger(__name__)
-
-# we want the cookie to be returned to us even when the request is the POSTed
-# result of a form on another domain, as is used with `response_mode=form_post`.
-#
-# Modern browsers will not do so unless we set SameSite=None; however *older*
-# browsers (including all versions of Safari on iOS 12?) don't support
-# SameSite=None, and interpret it as SameSite=Strict:
-# https://bugs.webkit.org/show_bug.cgi?id=198181
-#
-# As a rather painful workaround, we set *two* cookies, one with SameSite=None
-# and one with no SameSite, in the hope that at least one of them will get
-# back to us.
-#
-# Secure is necessary for SameSite=None (and, empirically, also breaks things
-# on iOS 12.)
-#
-# Here we have the names of the cookies, and the options we use to set them.
-_SESSION_COOKIES = [
- (b"oidc_session", b"Path=/_synapse/client/oidc; HttpOnly; Secure; SameSite=None"),
- (b"oidc_session_no_samesite", b"Path=/_synapse/client/oidc; HttpOnly"),
-]
-
-#: A token exchanged from the token endpoint, as per RFC6749 sec 5.1. and
-#: OpenID.Core sec 3.1.3.3.
-Token = TypedDict(
- "Token",
- {
- "access_token": str,
- "token_type": str,
- "id_token": Optional[str],
- "refresh_token": Optional[str],
- "expires_in": int,
- "scope": Optional[str],
- },
-)
-
-#: A JWK, as per RFC7517 sec 4. The type could be more precise than that, but
-#: there is no real point of doing this in our case.
-JWK = Dict[str, str]
-
-#: A JWK Set, as per RFC7517 sec 5.
-JWKS = TypedDict("JWKS", {"keys": List[JWK]})
-
-
-class OidcHandler:
- """Handles requests related to the OpenID Connect login flow."""
-
- def __init__(self, hs: "HomeServer"):
- self._sso_handler = hs.get_sso_handler()
-
- provider_confs = hs.config.oidc.oidc_providers
- # we should not have been instantiated if there is no configured provider.
- assert provider_confs
-
- self._token_generator = OidcSessionTokenGenerator(hs)
- self._providers = {
- p.idp_id: OidcProvider(hs, self._token_generator, p) for p in provider_confs
- } # type: Dict[str, OidcProvider]
-
- async def load_metadata(self) -> None:
- """Validate the config and load the metadata from the remote endpoint.
-
- Called at startup to ensure we have everything we need.
- """
- for idp_id, p in self._providers.items():
- try:
- await p.load_metadata()
- await p.load_jwks()
- except Exception as e:
- raise Exception(
- "Error while initialising OIDC provider %r" % (idp_id,)
- ) from e
-
- async def handle_oidc_callback(self, request: SynapseRequest) -> None:
- """Handle an incoming request to /_synapse/client/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 know the session is legit, we then delegate to the OIDC Provider
- implementation, which will exchange the code with the provider and complete the
- login/authentication.
-
- Args:
- request: the incoming request from the browser.
- """
- # This will always be set by the time Twisted calls us.
- assert request.args is not None
-
- # 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.
- logger.log(
- logging.INFO if error == "access_denied" else logging.ERROR,
- "Received OIDC callback with error: %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. See the comments on SESSION_COOKIES for why there
- # are two.
-
- for cookie_name, _ in _SESSION_COOKIES:
- session = request.getCookie(cookie_name) # type: Optional[bytes]
- if session is not None:
- break
- else:
- logger.info("Received OIDC callback, with no session cookie")
- self._sso_handler.render_error(
- request, "missing_session", "No session cookie found"
- )
- return
-
- # Remove the cookies. There is a good chance that if the callback failed
- # once, it will fail next time and the code will already be exchanged.
- # Removing the cookies early avoids spamming the provider with token requests.
- #
- # we have to build the header by hand rather than calling request.addCookie
- # because the latter does not support SameSite=None
- # (https://twistedmatrix.com/trac/ticket/10088)
-
- for cookie_name, options in _SESSION_COOKIES:
- request.cookies.append(
- b"%s=; Expires=Thu, Jan 01 1970 00:00:00 UTC; %s"
- % (cookie_name, options)
- )
-
- # Check for the state query parameter
- if b"state" not in request.args:
- logger.info("Received OIDC callback, with no state parameter")
- 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:
- session_data = self._token_generator.verify_oidc_session_token(
- session, state
- )
- except (MacaroonInitException, MacaroonDeserializationException, KeyError) as e:
- logger.exception("Invalid session for OIDC callback")
- self._sso_handler.render_error(request, "invalid_session", str(e))
- return
- except MacaroonInvalidSignatureException as e:
- logger.exception("Could not verify session for OIDC callback")
- self._sso_handler.render_error(request, "mismatching_session", str(e))
- return
-
- logger.info("Received OIDC callback for IdP %s", session_data.idp_id)
-
- oidc_provider = self._providers.get(session_data.idp_id)
- if not oidc_provider:
- logger.error("OIDC session uses unknown IdP %r", oidc_provider)
- self._sso_handler.render_error(request, "unknown_idp", "Unknown IdP")
- return
-
- 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
-
- code = request.args[b"code"][0].decode()
-
- await oidc_provider.handle_oidc_callback(request, session_data, code)
-
-
-class OidcError(Exception):
- """Used to catch errors when calling the token_endpoint"""
-
- def __init__(self, error, error_description=None):
- self.error = error
- self.error_description = error_description
-
- def __str__(self):
- if self.error_description:
- return "{}: {}".format(self.error, self.error_description)
- return self.error
-
-
-class OidcProvider:
- """Wraps the config for a single OIDC IdentityProvider
-
- Provides methods for handling redirect requests and callbacks via that particular
- IdP.
- """
-
- def __init__(
- self,
- hs: "HomeServer",
- token_generator: "OidcSessionTokenGenerator",
- provider: OidcProviderConfig,
- ):
- self._store = hs.get_datastore()
-
- self._token_generator = token_generator
-
- self._config = provider
- self._callback_url = hs.config.oidc_callback_url # type: str
-
- self._oidc_attribute_requirements = provider.attribute_requirements
- self._scopes = provider.scopes
- self._user_profile_method = provider.user_profile_method
-
- client_secret = None # type: Union[None, str, JwtClientSecret]
- if provider.client_secret:
- client_secret = provider.client_secret
- elif provider.client_secret_jwt_key:
- client_secret = JwtClientSecret(
- provider.client_secret_jwt_key,
- provider.client_id,
- provider.issuer,
- hs.get_clock(),
- )
-
- self._client_auth = ClientAuth(
- provider.client_id,
- client_secret,
- provider.client_auth_method,
- ) # type: ClientAuth
- self._client_auth_method = provider.client_auth_method
-
- # cache of metadata for the identity provider (endpoint uris, mostly). This is
- # loaded on-demand from the discovery endpoint (if discovery is enabled), with
- # possible overrides from the config. Access via `load_metadata`.
- self._provider_metadata = RetryOnExceptionCachedCall(self._load_metadata)
-
- # cache of JWKs used by the identity provider to sign tokens. Loaded on demand
- # from the IdP's jwks_uri, if required.
- self._jwks = RetryOnExceptionCachedCall(self._load_jwks)
-
- self._user_mapping_provider = provider.user_mapping_provider_class(
- provider.user_mapping_provider_config
- )
- self._skip_verification = provider.skip_verification
- self._allow_existing_users = provider.allow_existing_users
-
- self._http_client = hs.get_proxied_http_client()
- self._server_name = hs.config.server_name # type: str
-
- # identifier for the external_ids table
- self.idp_id = provider.idp_id
-
- # user-facing name of this auth provider
- self.idp_name = provider.idp_name
-
- # MXC URI for icon for this auth provider
- self.idp_icon = provider.idp_icon
-
- # optional brand identifier for this auth provider
- self.idp_brand = provider.idp_brand
-
- # Optional brand identifier for the unstable API (see MSC2858).
- self.unstable_idp_brand = provider.unstable_idp_brand
-
- self._sso_handler = hs.get_sso_handler()
-
- self._sso_handler.register_identity_provider(self)
-
- def _validate_metadata(self, m: OpenIDProviderMetadata) -> None:
- """Verifies the provider metadata.
-
- This checks the validity of the currently loaded provider. Not
- everything is checked, only:
-
- - ``issuer``
- - ``authorization_endpoint``
- - ``token_endpoint``
- - ``response_types_supported`` (checks if "code" is in it)
- - ``jwks_uri``
-
- Raises:
- ValueError: if something in the provider is not valid
- """
- # Skip verification to allow non-compliant providers (e.g. issuers not running on a secure origin)
- if self._skip_verification is True:
- return
-
- m.validate_issuer()
- m.validate_authorization_endpoint()
- m.validate_token_endpoint()
-
- if m.get("token_endpoint_auth_methods_supported") is not None:
- m.validate_token_endpoint_auth_methods_supported()
- if (
- self._client_auth_method
- not in m["token_endpoint_auth_methods_supported"]
- ):
- raise ValueError(
- '"{auth_method}" not in "token_endpoint_auth_methods_supported" ({supported!r})'.format(
- auth_method=self._client_auth_method,
- supported=m["token_endpoint_auth_methods_supported"],
- )
- )
-
- if m.get("response_types_supported") is not None:
- m.validate_response_types_supported()
-
- if "code" not in m["response_types_supported"]:
- raise ValueError(
- '"code" not in "response_types_supported" (%r)'
- % (m["response_types_supported"],)
- )
-
- # Ensure there's a userinfo endpoint to fetch from if it is required.
- if self._uses_userinfo:
- if m.get("userinfo_endpoint") is None:
- raise ValueError(
- 'provider has no "userinfo_endpoint", even though it is required'
- )
- else:
- # If we're not using userinfo, we need a valid jwks to validate the ID token
- m.validate_jwks_uri()
-
- @property
- def _uses_userinfo(self) -> bool:
- """Returns True if the ``userinfo_endpoint`` should be used.
-
- This is based on the requested scopes: if the scopes include
- ``openid``, the provider should give use an ID token containing the
- user information. If not, we should fetch them using the
- ``access_token`` with the ``userinfo_endpoint``.
- """
-
- return (
- "openid" not in self._scopes
- or self._user_profile_method == "userinfo_endpoint"
- )
-
- async def load_metadata(self, force: bool = False) -> OpenIDProviderMetadata:
- """Return the provider metadata.
-
- If this is the first call, the metadata is built from the config and from the
- metadata discovery endpoint (if enabled), and then validated. If the metadata
- is successfully validated, it is then cached for future use.
-
- Args:
- force: If true, any cached metadata is discarded to force a reload.
-
- Raises:
- ValueError: if something in the provider is not valid
-
- Returns:
- The provider's metadata.
- """
- if force:
- # reset the cached call to ensure we get a new result
- self._provider_metadata = RetryOnExceptionCachedCall(self._load_metadata)
-
- return await self._provider_metadata.get()
-
- async def _load_metadata(self) -> OpenIDProviderMetadata:
- # start out with just the issuer (unlike the other settings, discovered issuer
- # takes precedence over configured issuer, because configured issuer is
- # required for discovery to take place.)
- #
- metadata = OpenIDProviderMetadata(issuer=self._config.issuer)
-
- # load any data from the discovery endpoint, if enabled
- if self._config.discover:
- url = get_well_known_url(self._config.issuer, external=True)
- metadata_response = await self._http_client.get_json(url)
- metadata.update(metadata_response)
-
- # override any discovered data with any settings in our config
- if self._config.authorization_endpoint:
- metadata["authorization_endpoint"] = self._config.authorization_endpoint
-
- if self._config.token_endpoint:
- metadata["token_endpoint"] = self._config.token_endpoint
-
- if self._config.userinfo_endpoint:
- metadata["userinfo_endpoint"] = self._config.userinfo_endpoint
-
- if self._config.jwks_uri:
- metadata["jwks_uri"] = self._config.jwks_uri
-
- self._validate_metadata(metadata)
-
- return metadata
-
- async def load_jwks(self, force: bool = False) -> JWKS:
- """Load the JSON Web Key Set used to sign ID tokens.
-
- If we're not using the ``userinfo_endpoint``, user infos are extracted
- from the ID token, which is a JWT signed by keys given by the provider.
- The keys are then cached.
-
- Args:
- force: Force reloading the keys.
-
- Returns:
- The key set
-
- Looks like this::
-
- {
- 'keys': [
- {
- 'kid': 'abcdef',
- 'kty': 'RSA',
- 'alg': 'RS256',
- 'use': 'sig',
- 'e': 'XXXX',
- 'n': 'XXXX',
- }
- ]
- }
- """
- if force:
- # reset the cached call to ensure we get a new result
- self._jwks = RetryOnExceptionCachedCall(self._load_jwks)
- return await self._jwks.get()
-
- async def _load_jwks(self) -> JWKS:
- if self._uses_userinfo:
- # We're not using jwt signing, return an empty jwk set
- return {"keys": []}
-
- metadata = await self.load_metadata()
-
- # Load the JWKS using the `jwks_uri` metadata.
- uri = metadata.get("jwks_uri")
- if not uri:
- # this should be unreachable: load_metadata validates that
- # there is a jwks_uri in the metadata if _uses_userinfo is unset
- raise RuntimeError('Missing "jwks_uri" in metadata')
-
- jwk_set = await self._http_client.get_json(uri)
-
- return jwk_set
-
- async def _exchange_code(self, code: str) -> Token:
- """Exchange an authorization code for a token.
-
- This calls the ``token_endpoint`` with the authorization code we
- received in the callback to exchange it for a token. The call uses the
- ``ClientAuth`` to authenticate with the client with its ID and secret.
-
- See:
- https://tools.ietf.org/html/rfc6749#section-3.2
- https://openid.net/specs/openid-connect-core-1_0.html#TokenEndpoint
-
- Args:
- code: The authorization code we got from the callback.
-
- Returns:
- A dict containing various tokens.
-
- May look like this::
-
- {
- 'token_type': 'bearer',
- 'access_token': 'abcdef',
- 'expires_in': 3599,
- 'id_token': 'ghijkl',
- 'refresh_token': 'mnopqr',
- }
-
- Raises:
- OidcError: when the ``token_endpoint`` returned an error.
- """
- metadata = await self.load_metadata()
- token_endpoint = metadata.get("token_endpoint")
- raw_headers = {
- "Content-Type": "application/x-www-form-urlencoded",
- "User-Agent": self._http_client.user_agent,
- "Accept": "application/json",
- }
-
- args = {
- "grant_type": "authorization_code",
- "code": code,
- "redirect_uri": self._callback_url,
- }
- body = urlencode(args, True)
-
- # Fill the body/headers with credentials
- uri, raw_headers, body = self._client_auth.prepare(
- method="POST", uri=token_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,
- )
-
- # This is used in multiple error messages below
- status = "{code} {phrase}".format(
- code=response.code, phrase=response.phrase.decode("utf-8")
- )
-
- resp_body = await make_deferred_yieldable(readBody(response))
-
- if response.code >= 500:
- # In case of a server error, we should first try to decode the body
- # and check for an error field. If not, we respond with a generic
- # error message.
- try:
- resp = json_decoder.decode(resp_body.decode("utf-8"))
- error = resp["error"]
- description = resp.get("error_description", error)
- except (ValueError, KeyError):
- # Catch ValueError for the JSON decoding and KeyError for the "error" field
- error = "server_error"
- description = (
- (
- 'Authorization server responded with a "{status}" error '
- "while exchanging the authorization code."
- ).format(status=status),
- )
-
- raise OidcError(error, description)
-
- # Since it is a not a 5xx code, body should be a valid JSON. It will
- # raise if not.
- resp = json_decoder.decode(resp_body.decode("utf-8"))
-
- if "error" in resp:
- error = resp["error"]
- # In case the authorization server responded with an error field,
- # it should be a 4xx code. If not, warn about it but don't do
- # anything special and report the original error message.
- if response.code < 400:
- logger.debug(
- "Invalid response from the authorization server: "
- 'responded with a "{status}" '
- "but body has an error field: {error!r}".format(
- status=status, error=resp["error"]
- )
- )
-
- description = resp.get("error_description", error)
- raise OidcError(error, description)
-
- # Now, this should not be an error. According to RFC6749 sec 5.1, it
- # should be a 200 code. We're a bit more flexible than that, and will
- # only throw on a 4xx code.
- if response.code >= 400:
- description = (
- 'Authorization server responded with a "{status}" error '
- 'but did not include an "error" field in its response.'.format(
- status=status
- )
- )
- logger.warning(description)
- # Body was still valid JSON. Might be useful to log it for debugging.
- logger.warning("Code exchange response: {resp!r}".format(resp=resp))
- raise OidcError("server_error", description)
-
- return resp
-
- async def _fetch_userinfo(self, token: Token) -> UserInfo:
- """Fetch user information from the ``userinfo_endpoint``.
-
- Args:
- token: the token given by the ``token_endpoint``.
- Must include an ``access_token`` field.
-
- Returns:
- UserInfo: an object representing the user.
- """
- logger.debug("Using the OAuth2 access_token to request userinfo")
- metadata = await self.load_metadata()
-
- resp = await self._http_client.get_json(
- metadata["userinfo_endpoint"],
- headers={"Authorization": ["Bearer {}".format(token["access_token"])]},
- )
-
- logger.debug("Retrieved user info from userinfo endpoint: %r", resp)
-
- return UserInfo(resp)
-
- async def _parse_id_token(self, token: Token, nonce: str) -> UserInfo:
- """Return an instance of UserInfo from token's ``id_token``.
-
- Args:
- token: the token given by the ``token_endpoint``.
- Must include an ``id_token`` field.
- nonce: the nonce value originally sent in the initial authorization
- request. This value should match the one inside the token.
-
- Returns:
- An object representing the user.
- """
- metadata = await self.load_metadata()
- claims_params = {
- "nonce": nonce,
- "client_id": self._client_auth.client_id,
- }
- if "access_token" in token:
- # If we got an `access_token`, there should be an `at_hash` claim
- # in the `id_token` that we can check against.
- claims_params["access_token"] = token["access_token"]
- claims_cls = CodeIDToken
- else:
- claims_cls = ImplicitIDToken
-
- alg_values = metadata.get("id_token_signing_alg_values_supported", ["RS256"])
- jwt = JsonWebToken(alg_values)
-
- claim_options = {"iss": {"values": [metadata["issuer"]]}}
-
- id_token = token["id_token"]
- logger.debug("Attempting to decode JWT id_token %r", id_token)
-
- # Try to decode the keys in cache first, then retry by forcing the keys
- # to be reloaded
- jwk_set = await self.load_jwks()
- try:
- claims = jwt.decode(
- id_token,
- key=jwk_set,
- claims_cls=claims_cls,
- claims_options=claim_options,
- claims_params=claims_params,
- )
- except ValueError:
- logger.info("Reloading JWKS after decode error")
- jwk_set = await self.load_jwks(force=True) # try reloading the jwks
- claims = jwt.decode(
- id_token,
- key=jwk_set,
- claims_cls=claims_cls,
- claims_options=claim_options,
- claims_params=claims_params,
- )
-
- logger.debug("Decoded id_token JWT %r; validating", claims)
-
- claims.validate(leeway=120) # allows 2 min of clock skew
- return UserInfo(claims)
-
- async def handle_redirect_request(
- self,
- request: SynapseRequest,
- client_redirect_url: Optional[bytes],
- ui_auth_session_id: Optional[str] = None,
- ) -> str:
- """Handle an incoming request to /login/sso/redirect
-
- It returns a redirect to the authorization endpoint with a few
- parameters:
-
- - ``client_id``: the client ID set in ``oidc_config.client_id``
- - ``response_type``: ``code``
- - ``redirect_uri``: the callback URL ; ``{base url}/_synapse/client/oidc/callback``
- - ``scope``: the list of scopes set in ``oidc_config.scopes``
- - ``state``: a random string
- - ``nonce``: a random string
-
- In addition generating a redirect URL, we are setting a cookie with
- a signed macaroon token containing the state, the nonce and the
- client_redirect_url params. Those are then checked when the client
- comes back from the provider.
-
- Args:
- request: the incoming request from the browser.
- We'll respond to it with a redirect and a cookie.
- client_redirect_url: the URL that we should redirect the client to
- when everything is done (or None for UI Auth)
- 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()
-
- if not client_redirect_url:
- client_redirect_url = b""
-
- cookie = self._token_generator.generate_oidc_session_token(
- state=state,
- session_data=OidcSessionData(
- idp_id=self.idp_id,
- nonce=nonce,
- client_redirect_url=client_redirect_url.decode(),
- ui_auth_session_id=ui_auth_session_id or "",
- ),
- )
-
- # Set the cookies. See the comments on _SESSION_COOKIES for why there are two.
- #
- # we have to build the header by hand rather than calling request.addCookie
- # because the latter does not support SameSite=None
- # (https://twistedmatrix.com/trac/ticket/10088)
-
- for cookie_name, options in _SESSION_COOKIES:
- request.cookies.append(
- b"%s=%s; Max-Age=3600; %s"
- % (cookie_name, cookie.encode("utf-8"), options)
- )
-
- 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, session_data: "OidcSessionData", code: str
- ) -> None:
- """Handle an incoming request to /_synapse/client/oidc/callback
-
- By this time we have already validated the session on the synapse side, and
- now need to do the provider-specific operations. This includes:
-
- - 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.
- session_data: the session data, extracted from our cookie
- code: The authorization code we got from the callback.
- """
- # Exchange the code with the provider
- try:
- logger.debug("Exchanging OAuth2 code for a token")
- token = await self._exchange_code(code)
- except OidcError as e:
- logger.exception("Could not exchange OAuth2 code")
- self._sso_handler.render_error(request, e.error, e.error_description)
- return
-
- logger.debug("Successfully obtained OAuth2 token data: %r", 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:
- 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:
- try:
- userinfo = await self._parse_id_token(token, nonce=session_data.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 session_data.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.idp_id, remote_user_id, session_data.ui_auth_session_id, request
- )
-
- # otherwise, it's a login
- logger.debug("Userinfo for OIDC login: %s", userinfo)
-
- # Ensure that the attributes of the logged in user meet the required
- # attributes by checking the userinfo against attribute_requirements
- # In order to deal with the fact that OIDC userinfo can contain many
- # types of data, we wrap non-list values in lists.
- if not self._sso_handler.check_required_attributes(
- request,
- {k: v if isinstance(v, list) else [v] for k, v in userinfo.items()},
- self._oidc_attribute_requirements,
- ):
- return
-
- # Call the mapper to register/login the user
- try:
- await self._complete_oidc_login(
- userinfo, token, request, session_data.client_redirect_url
- )
- except MappingException as e:
- logger.exception("Could not map user")
- self._sso_handler.render_error(request, "mapping_error", str(e))
-
- async def _complete_oidc_login(
- self,
- userinfo: UserInfo,
- token: Token,
- request: SynapseRequest,
- client_redirect_url: str,
- ) -> None:
- """Given a UserInfo response, complete the login flow
-
- 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.
-
- Otherwise, render a redirect back to the client_redirect_url with a loginToken.
-
- Args:
- userinfo: an object representing the user
- token: a dict with the tokens obtained from the provider
- request: The request to respond to
- client_redirect_url: The redirect URL passed in by the client.
-
- Raises:
- MappingException: if there was an error while mapping some properties
- """
- 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
-
- # 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)
-
- await self._sso_handler.complete_sso_login_request(
- self.idp_id,
- remote_user_id,
- request,
- client_redirect_url,
- oidc_response_to_user_attributes,
- grandfather_existing_users,
- extra_attributes,
- )
-
- 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)
-
-
-# number of seconds a newly-generated client secret should be valid for
-CLIENT_SECRET_VALIDITY_SECONDS = 3600
-
-# minimum remaining validity on a client secret before we should generate a new one
-CLIENT_SECRET_MIN_VALIDITY_SECONDS = 600
-
-
-class JwtClientSecret:
- """A class which generates a new client secret on demand, based on a JWK
-
- This implementation is designed to comply with the requirements for Apple Sign in:
- https://developer.apple.com/documentation/sign_in_with_apple/generate_and_validate_tokens#3262048
-
- It looks like those requirements are based on https://tools.ietf.org/html/rfc7523,
- but it's worth noting that we still put the generated secret in the "client_secret"
- field (or rather, whereever client_auth_method puts it) rather than in a
- client_assertion field in the body as that RFC seems to require.
- """
-
- def __init__(
- self,
- key: OidcProviderClientSecretJwtKey,
- oauth_client_id: str,
- oauth_issuer: str,
- clock: Clock,
- ):
- self._key = key
- self._oauth_client_id = oauth_client_id
- self._oauth_issuer = oauth_issuer
- self._clock = clock
- self._cached_secret = b""
- self._cached_secret_replacement_time = 0
-
- def __str__(self):
- # if client_auth_method is client_secret_basic, then ClientAuth.prepare calls
- # encode_client_secret_basic, which calls "{}".format(secret), which ends up
- # here.
- return self._get_secret().decode("ascii")
-
- def __bytes__(self):
- # if client_auth_method is client_secret_post, then ClientAuth.prepare calls
- # encode_client_secret_post, which ends up here.
- return self._get_secret()
-
- def _get_secret(self) -> bytes:
- now = self._clock.time()
-
- # if we have enough validity on our existing secret, use it
- if now < self._cached_secret_replacement_time:
- return self._cached_secret
-
- issued_at = int(now)
- expires_at = issued_at + CLIENT_SECRET_VALIDITY_SECONDS
-
- # we copy the configured header because jwt.encode modifies it.
- header = dict(self._key.jwt_header)
-
- # see https://tools.ietf.org/html/rfc7523#section-3
- payload = {
- "sub": self._oauth_client_id,
- "aud": self._oauth_issuer,
- "iat": issued_at,
- "exp": expires_at,
- **self._key.jwt_payload,
- }
- logger.info(
- "Generating new JWT for %s: %s %s", self._oauth_issuer, header, payload
- )
- self._cached_secret = jwt.encode(header, payload, self._key.key)
- self._cached_secret_replacement_time = (
- expires_at - CLIENT_SECRET_MIN_VALIDITY_SECONDS
- )
- return self._cached_secret
-
-
-class OidcSessionTokenGenerator:
- """Methods for generating and checking OIDC Session cookies."""
-
- def __init__(self, hs: "HomeServer"):
- self._clock = hs.get_clock()
- self._server_name = hs.hostname
- self._macaroon_secret_key = hs.config.key.macaroon_secret_key
-
- def generate_oidc_session_token(
- self,
- state: str,
- session_data: "OidcSessionData",
- 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.
- session_data: data to include in the session token.
- 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("idp_id = %s" % (session_data.idp_id,))
- macaroon.add_first_party_caveat("nonce = %s" % (session_data.nonce,))
- macaroon.add_first_party_caveat(
- "client_redirect_url = %s" % (session_data.client_redirect_url,)
- )
- macaroon.add_first_party_caveat(
- "ui_auth_session_id = %s" % (session_data.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
- ) -> "OidcSessionData":
- """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 data extracted from the session cookie
-
- Raises:
- KeyError if an expected caveat is missing from the macaroon.
- """
- 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("idp_id = "))
- v.satisfy_general(lambda c: c.startswith("client_redirect_url = "))
- v.satisfy_general(lambda c: c.startswith("ui_auth_session_id = "))
- satisfy_expiry(v, self._clock.time_msec)
-
- v.verify(macaroon, self._macaroon_secret_key)
-
- # Extract the session data from the token.
- nonce = get_value_from_macaroon(macaroon, "nonce")
- idp_id = get_value_from_macaroon(macaroon, "idp_id")
- client_redirect_url = get_value_from_macaroon(macaroon, "client_redirect_url")
- ui_auth_session_id = get_value_from_macaroon(macaroon, "ui_auth_session_id")
- return OidcSessionData(
- nonce=nonce,
- idp_id=idp_id,
- client_redirect_url=client_redirect_url,
- ui_auth_session_id=ui_auth_session_id,
- )
-
-
-@attr.s(frozen=True, slots=True)
-class OidcSessionData:
- """The attributes which are stored in a OIDC session cookie"""
-
- # the Identity Provider being used
- idp_id = attr.ib(type=str)
-
- # The `nonce` parameter passed to the OIDC provider.
- nonce = attr.ib(type=str)
-
- # The URL the client gave when it initiated the flow. ("" if this is a UI Auth)
- client_redirect_url = attr.ib(type=str)
-
- # The session ID of the ongoing UI Auth ("" if this is a login)
- ui_auth_session_id = attr.ib(type=str)
-
-
-UserAttributeDict = TypedDict(
- "UserAttributeDict",
- {"localpart": Optional[str], "display_name": Optional[str], "emails": List[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(slots=True, frozen=True)
-class JinjaOidcMappingConfig:
- subject_claim = attr.ib(type=str)
- localpart_template = attr.ib(type=Optional[Template])
- display_name_template = attr.ib(type=Optional[Template])
- email_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")
-
- def parse_template_config(option_name: str) -> Optional[Template]:
- if option_name not in config:
- return None
- try:
- return env.from_string(config[option_name])
- except Exception as e:
- raise ConfigError("invalid jinja template", path=[option_name]) from e
-
- localpart_template = parse_template_config("localpart_template")
- display_name_template = parse_template_config("display_name_template")
- email_template = parse_template_config("email_template")
-
- 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("must be a dict", path=["extra_attributes"])
-
- 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", path=["extra_attributes", key]
- ) from e
-
- return JinjaOidcMappingConfig(
- subject_claim=subject_claim,
- localpart_template=localpart_template,
- display_name_template=display_name_template,
- email_template=email_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 = None
-
- if self._config.localpart_template:
- 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 ""
-
- def render_template_field(template: Optional[Template]) -> Optional[str]:
- if template is None:
- return None
- return template.render(user=userinfo).strip()
-
- display_name = render_template_field(self._config.display_name_template)
- if display_name == "":
- display_name = None
-
- emails = [] # type: List[str]
- email = render_template_field(self._config.email_template)
- if email:
- emails.append(email)
-
- return UserAttributeDict(
- localpart=localpart, display_name=display_name, emails=emails
- )
-
- 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
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