From 4575ad0b1e86c814e6d1c3ca6ac31ba4eeeb5c66 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Date: Fri, 15 Jan 2021 13:22:12 +0000 Subject: [PATCH] Store an IdP ID in the OIDC session (#9109) Again in preparation for handling more than one OIDC provider, add a new caveat to the macaroon used as an OIDC session cookie, which remembers which OIDC provider we are talking to. In future, when we get a callback, we'll need it to make sure we talk to the right IdP. As part of this, I'm adding an idp_id and idp_name field to the OIDC configuration object. They aren't yet documented, and we'll just use the old values by default. --- changelog.d/9109.feature | 1 + synapse/config/oidc_config.py | 26 +++++++++++++++++++++++--- synapse/handlers/oidc_handler.py | 22 ++++++++++++++++------ tests/handlers/test_oidc.py | 3 ++- 4 files changed, 42 insertions(+), 10 deletions(-) create mode 100644 changelog.d/9109.feature diff --git a/changelog.d/9109.feature b/changelog.d/9109.feature new file mode 100644 index 0000000000..01a24dcf49 --- /dev/null +++ b/changelog.d/9109.feature @@ -0,0 +1 @@ +Add support for multiple SSO Identity Providers. diff --git a/synapse/config/oidc_config.py b/synapse/config/oidc_config.py index c705de5694..fddca19223 100644 --- a/synapse/config/oidc_config.py +++ b/synapse/config/oidc_config.py @@ -1,6 +1,6 @@ # -*- coding: utf-8 -*- # Copyright 2020 Quentin Gliech -# Copyright 2020 The Matrix.org Foundation C.I.C. +# Copyright 2020-2021 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. @@ -14,6 +14,7 @@ # See the License for the specific language governing permissions and # limitations under the License. +import string from typing import Optional, Type import attr @@ -38,7 +39,7 @@ class OIDCConfig(Config): oidc_config = config.get("oidc_config") if oidc_config and oidc_config.get("enabled", False): - validate_config(OIDC_PROVIDER_CONFIG_SCHEMA, oidc_config, "oidc_config") + validate_config(OIDC_PROVIDER_CONFIG_SCHEMA, oidc_config, ("oidc_config",)) self.oidc_provider = _parse_oidc_config_dict(oidc_config) if not self.oidc_provider: @@ -205,6 +206,8 @@ OIDC_PROVIDER_CONFIG_SCHEMA = { "type": "object", "required": ["issuer", "client_id", "client_secret"], "properties": { + "idp_id": {"type": "string", "minLength": 1, "maxLength": 128}, + "idp_name": {"type": "string"}, "discover": {"type": "boolean"}, "issuer": {"type": "string"}, "client_id": {"type": "string"}, @@ -277,7 +280,17 @@ def _parse_oidc_config_dict(oidc_config: JsonDict) -> "OidcProviderConfig": "methods: %s" % (", ".join(missing_methods),) ) + # MSC2858 will appy certain limits in what can be used as an IdP id, so let's + # enforce those limits now. + idp_id = oidc_config.get("idp_id", "oidc") + valid_idp_chars = set(string.ascii_letters + string.digits + "-._~") + + if any(c not in valid_idp_chars for c in idp_id): + raise ConfigError('idp_id may only contain A-Z, a-z, 0-9, "-", ".", "_", "~"') + return OidcProviderConfig( + idp_id=idp_id, + idp_name=oidc_config.get("idp_name", "OIDC"), discover=oidc_config.get("discover", True), issuer=oidc_config["issuer"], client_id=oidc_config["client_id"], @@ -296,8 +309,15 @@ def _parse_oidc_config_dict(oidc_config: JsonDict) -> "OidcProviderConfig": ) -@attr.s +@attr.s(slots=True, frozen=True) class OidcProviderConfig: + # a unique identifier for this identity provider. Used in the 'user_external_ids' + # table, as well as the query/path parameter used in the login protocol. + idp_id = attr.ib(type=str) + + # user-facing name for this identity provider. + idp_name = attr.ib(type=str) + # whether the OIDC discovery mechanism is used to discover endpoints discover = attr.ib(type=bool) diff --git a/synapse/handlers/oidc_handler.py b/synapse/handlers/oidc_handler.py index d6347bb1b8..f63a90ec5c 100644 --- a/synapse/handlers/oidc_handler.py +++ b/synapse/handlers/oidc_handler.py @@ -175,7 +175,7 @@ class OidcHandler: session_data = self._token_generator.verify_oidc_session_token( session, state ) - except MacaroonDeserializationException as e: + except (MacaroonDeserializationException, ValueError) as e: logger.exception("Invalid session") self._sso_handler.render_error(request, "invalid_session", str(e)) return @@ -253,10 +253,10 @@ class OidcProvider: self._server_name = hs.config.server_name # type: str # identifier for the external_ids table - self.idp_id = "oidc" + self.idp_id = provider.idp_id # user-facing name of this auth provider - self.idp_name = "OIDC" + self.idp_name = provider.idp_name self._sso_handler = hs.get_sso_handler() @@ -656,6 +656,7 @@ class OidcProvider: 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, @@ -924,6 +925,7 @@ class OidcSessionTokenGenerator: 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,) @@ -952,6 +954,9 @@ class OidcSessionTokenGenerator: Returns: The data extracted from the session cookie + + Raises: + ValueError if an expected caveat is missing from the macaroon. """ macaroon = pymacaroons.Macaroon.deserialize(session) @@ -960,6 +965,7 @@ class OidcSessionTokenGenerator: 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 = ")) # Sometimes there's a UI auth session ID, it seems to be OK to attempt # to always satisfy this. @@ -968,9 +974,9 @@ class OidcSessionTokenGenerator: v.verify(macaroon, self._macaroon_secret_key) - # Extract the `nonce`, `client_redirect_url`, and maybe the - # `ui_auth_session_id` from the token. + # Extract the session data from the token. nonce = self._get_value_from_macaroon(macaroon, "nonce") + idp_id = self._get_value_from_macaroon(macaroon, "idp_id") client_redirect_url = self._get_value_from_macaroon( macaroon, "client_redirect_url" ) @@ -983,6 +989,7 @@ class OidcSessionTokenGenerator: return OidcSessionData( nonce=nonce, + idp_id=idp_id, client_redirect_url=client_redirect_url, ui_auth_session_id=ui_auth_session_id, ) @@ -998,7 +1005,7 @@ class OidcSessionTokenGenerator: The extracted value Raises: - Exception: if the caveat was not in the macaroon + ValueError: if the caveat was not in the macaroon """ prefix = key + " = " for caveat in macaroon.caveats: @@ -1019,6 +1026,9 @@ class OidcSessionTokenGenerator: 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) diff --git a/tests/handlers/test_oidc.py b/tests/handlers/test_oidc.py index 5d338bea87..38ae8ca19e 100644 --- a/tests/handlers/test_oidc.py +++ b/tests/handlers/test_oidc.py @@ -848,6 +848,7 @@ class OidcHandlerTestCase(HomeserverTestCase): return self.handler._token_generator.generate_oidc_session_token( state=state, session_data=OidcSessionData( + idp_id="oidc", nonce=nonce, client_redirect_url=client_redirect_url, ui_auth_session_id=ui_auth_session_id, @@ -990,7 +991,7 @@ async def _make_callback_with_userinfo( session = handler._token_generator.generate_oidc_session_token( state=state, session_data=OidcSessionData( - nonce="nonce", client_redirect_url=client_redirect_url, + idp_id="oidc", nonce="nonce", client_redirect_url=client_redirect_url, ), ) request = _build_callback_request("code", state, session)