diff options
Diffstat (limited to '')
| -rw-r--r-- | changelog.d/7136.misc | 1 | ||||
| -rw-r--r-- | synapse/handlers/cas_handler.py | 204 | ||||
| -rw-r--r-- | synapse/rest/client/v1/login.py | 171 | ||||
| -rw-r--r-- | synapse/server.py | 5 | ||||
| -rw-r--r-- | tox.ini | 1 |
5 files changed, 227 insertions, 155 deletions
diff --git a/changelog.d/7136.misc b/changelog.d/7136.misc new file mode 100644 index 0000000000..3f666d25fd --- /dev/null +++ b/changelog.d/7136.misc @@ -0,0 +1 @@ +Refactored the CAS authentication logic to a separate class. diff --git a/synapse/handlers/cas_handler.py b/synapse/handlers/cas_handler.py new file mode 100644 index 0000000000..f8dc274b78 --- /dev/null +++ b/synapse/handlers/cas_handler.py @@ -0,0 +1,204 @@ +# -*- coding: utf-8 -*- +# Copyright 2020 The Matrix.org Foundation C.I.C. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +import logging +import xml.etree.ElementTree as ET +from typing import AnyStr, Dict, Optional, Tuple + +from six.moves import urllib + +from twisted.web.client import PartialDownloadError + +from synapse.api.errors import Codes, LoginError +from synapse.http.site import SynapseRequest +from synapse.types import UserID, map_username_to_mxid_localpart + +logger = logging.getLogger(__name__) + + +class CasHandler: + """ + Utility class for to handle the response from a CAS SSO service. + + Args: + hs (synapse.server.HomeServer) + """ + + def __init__(self, hs): + self._hostname = hs.hostname + self._auth_handler = hs.get_auth_handler() + self._registration_handler = hs.get_registration_handler() + + self._cas_server_url = hs.config.cas_server_url + self._cas_service_url = hs.config.cas_service_url + self._cas_displayname_attribute = hs.config.cas_displayname_attribute + self._cas_required_attributes = hs.config.cas_required_attributes + + self._http_client = hs.get_proxied_http_client() + + def _build_service_param(self, client_redirect_url: AnyStr) -> str: + return "%s%s?%s" % ( + self._cas_service_url, + "/_matrix/client/r0/login/cas/ticket", + urllib.parse.urlencode({"redirectUrl": client_redirect_url}), + ) + + async def _handle_cas_response( + self, request: SynapseRequest, cas_response_body: str, client_redirect_url: str + ) -> None: + """ + Retrieves the user and display name from the CAS response and continues with the authentication. + + Args: + request: The original client request. + cas_response_body: The response from the CAS server. + client_redirect_url: The URl to redirect the client to when + everything is done. + """ + user, attributes = self._parse_cas_response(cas_response_body) + displayname = attributes.pop(self._cas_displayname_attribute, None) + + for required_attribute, required_value in self._cas_required_attributes.items(): + # If required attribute was not in CAS Response - Forbidden + if required_attribute not in attributes: + raise LoginError(401, "Unauthorized", errcode=Codes.UNAUTHORIZED) + + # Also need to check value + if required_value is not None: + actual_value = attributes[required_attribute] + # If required attribute value does not match expected - Forbidden + if required_value != actual_value: + raise LoginError(401, "Unauthorized", errcode=Codes.UNAUTHORIZED) + + await self._on_successful_auth(user, request, client_redirect_url, displayname) + + def _parse_cas_response( + self, cas_response_body: str + ) -> Tuple[str, Dict[str, Optional[str]]]: + """ + Retrieve the user and other parameters from the CAS response. + + Args: + cas_response_body: The response from the CAS query. + + Returns: + A tuple of the user and a mapping of other attributes. + """ + user = None + attributes = {} + try: + root = ET.fromstring(cas_response_body) + if not root.tag.endswith("serviceResponse"): + raise Exception("root of CAS response is not serviceResponse") + success = root[0].tag.endswith("authenticationSuccess") + for child in root[0]: + if child.tag.endswith("user"): + user = child.text + if child.tag.endswith("attributes"): + for attribute in child: + # ElementTree library expands the namespace in + # attribute tags to the full URL of the namespace. + # We don't care about namespace here and it will always + # be encased in curly braces, so we remove them. + tag = attribute.tag + if "}" in tag: + tag = tag.split("}")[1] + attributes[tag] = attribute.text + if user is None: + raise Exception("CAS response does not contain user") + except Exception: + logger.exception("Error parsing CAS response") + raise LoginError(401, "Invalid CAS response", errcode=Codes.UNAUTHORIZED) + if not success: + raise LoginError( + 401, "Unsuccessful CAS response", errcode=Codes.UNAUTHORIZED + ) + return user, attributes + + async def _on_successful_auth( + self, + username: str, + request: SynapseRequest, + client_redirect_url: str, + user_display_name: Optional[str] = None, + ) -> None: + """Called once the user has successfully authenticated with the SSO. + + Registers the user if necessary, and then returns a redirect (with + a login token) to the client. + + Args: + username: the remote user id. We'll map this onto + something sane for a MXID localpath. + + request: the incoming request from the browser. We'll + respond to it with a redirect. + + client_redirect_url: the redirect_url the client gave us when + it first started the process. + + user_display_name: if set, and we have to register a new user, + we will set their displayname to this. + """ + localpart = map_username_to_mxid_localpart(username) + user_id = UserID(localpart, self._hostname).to_string() + registered_user_id = await self._auth_handler.check_user_exists(user_id) + if not registered_user_id: + registered_user_id = await self._registration_handler.register_user( + localpart=localpart, default_display_name=user_display_name + ) + + self._auth_handler.complete_sso_login( + registered_user_id, request, client_redirect_url + ) + + def handle_redirect_request(self, client_redirect_url: bytes) -> bytes: + """ + Generates a URL to the CAS server where the client should be redirected. + + Args: + client_redirect_url: The final URL the client should go to after the + user has negotiated SSO. + + Returns: + The URL to redirect to. + """ + args = urllib.parse.urlencode( + {"service": self._build_service_param(client_redirect_url)} + ) + + return ("%s/login?%s" % (self._cas_server_url, args)).encode("ascii") + + async def handle_ticket_request( + self, request: SynapseRequest, client_redirect_url: str, ticket: str + ) -> None: + """ + Validates a CAS ticket sent by the client for login/registration. + + On a successful request, writes a redirect to the request. + """ + uri = self._cas_server_url + "/proxyValidate" + args = { + "ticket": ticket, + "service": self._build_service_param(client_redirect_url), + } + try: + body = await self._http_client.get_raw(uri, args) + except PartialDownloadError as pde: + # Twisted raises this error if the connection is closed, + # even if that's being used old-http style to signal end-of-data + body = pde.response + + await self._handle_cas_response(request, body, client_redirect_url) diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py index 56d713462a..59593cbf6e 100644 --- a/synapse/rest/client/v1/login.py +++ b/synapse/rest/client/v1/login.py @@ -14,11 +14,6 @@ # limitations under the License. import logging -import xml.etree.ElementTree as ET - -from six.moves import urllib - -from twisted.web.client import PartialDownloadError from synapse.api.errors import Codes, LoginError, SynapseError from synapse.api.ratelimiting import Ratelimiter @@ -28,9 +23,10 @@ from synapse.http.servlet import ( parse_json_object_from_request, parse_string, ) +from synapse.http.site import SynapseRequest from synapse.rest.client.v2_alpha._base import client_patterns from synapse.rest.well_known import WellKnownBuilder -from synapse.types import UserID, map_username_to_mxid_localpart +from synapse.types import UserID from synapse.util.msisdn import phone_number_to_msisdn logger = logging.getLogger(__name__) @@ -72,14 +68,6 @@ def login_id_thirdparty_from_phone(identifier): return {"type": "m.id.thirdparty", "medium": "msisdn", "address": msisdn} -def build_service_param(cas_service_url, client_redirect_url): - return "%s%s?redirectUrl=%s" % ( - cas_service_url, - "/_matrix/client/r0/login/cas/ticket", - urllib.parse.quote(client_redirect_url, safe=""), - ) - - class LoginRestServlet(RestServlet): PATTERNS = client_patterns("/login$", v1=True) CAS_TYPE = "m.login.cas" @@ -409,7 +397,7 @@ class BaseSSORedirectServlet(RestServlet): PATTERNS = client_patterns("/login/(cas|sso)/redirect", v1=True) - def on_GET(self, request): + def on_GET(self, request: SynapseRequest): args = request.args if b"redirectUrl" not in args: return 400, "Redirect URL not specified for SSO auth" @@ -418,15 +406,15 @@ class BaseSSORedirectServlet(RestServlet): request.redirect(sso_url) finish_request(request) - def get_sso_url(self, client_redirect_url): + def get_sso_url(self, client_redirect_url: bytes) -> bytes: """Get the URL to redirect to, to perform SSO auth Args: - client_redirect_url (bytes): the URL that we should redirect the + client_redirect_url: the URL that we should redirect the client to when everything is done Returns: - bytes: URL to redirect to + URL to redirect to """ # to be implemented by subclasses raise NotImplementedError() @@ -434,16 +422,10 @@ class BaseSSORedirectServlet(RestServlet): class CasRedirectServlet(BaseSSORedirectServlet): def __init__(self, hs): - super(CasRedirectServlet, self).__init__() - self.cas_server_url = hs.config.cas_server_url - self.cas_service_url = hs.config.cas_service_url + self._cas_handler = hs.get_cas_handler() - def get_sso_url(self, client_redirect_url): - args = urllib.parse.urlencode( - {"service": build_service_param(self.cas_service_url, client_redirect_url)} - ) - - return "%s/login?%s" % (self.cas_server_url, args) + def get_sso_url(self, client_redirect_url: bytes) -> bytes: + return self._cas_handler.handle_redirect_request(client_redirect_url) class CasTicketServlet(RestServlet): @@ -451,81 +433,15 @@ class CasTicketServlet(RestServlet): def __init__(self, hs): super(CasTicketServlet, self).__init__() - self.cas_server_url = hs.config.cas_server_url - self.cas_service_url = hs.config.cas_service_url - self.cas_displayname_attribute = hs.config.cas_displayname_attribute - self.cas_required_attributes = hs.config.cas_required_attributes - self._sso_auth_handler = SSOAuthHandler(hs) - self._http_client = hs.get_proxied_http_client() - - async def on_GET(self, request): - client_redirect_url = parse_string(request, "redirectUrl", required=True) - uri = self.cas_server_url + "/proxyValidate" - args = { - "ticket": parse_string(request, "ticket", required=True), - "service": build_service_param(self.cas_service_url, client_redirect_url), - } - try: - body = await self._http_client.get_raw(uri, args) - except PartialDownloadError as pde: - # Twisted raises this error if the connection is closed, - # even if that's being used old-http style to signal end-of-data - body = pde.response - result = await self.handle_cas_response(request, body, client_redirect_url) - return result + self._cas_handler = hs.get_cas_handler() - def handle_cas_response(self, request, cas_response_body, client_redirect_url): - user, attributes = self.parse_cas_response(cas_response_body) - displayname = attributes.pop(self.cas_displayname_attribute, None) - - for required_attribute, required_value in self.cas_required_attributes.items(): - # If required attribute was not in CAS Response - Forbidden - if required_attribute not in attributes: - raise LoginError(401, "Unauthorized", errcode=Codes.UNAUTHORIZED) - - # Also need to check value - if required_value is not None: - actual_value = attributes[required_attribute] - # If required attribute value does not match expected - Forbidden - if required_value != actual_value: - raise LoginError(401, "Unauthorized", errcode=Codes.UNAUTHORIZED) - - return self._sso_auth_handler.on_successful_auth( - user, request, client_redirect_url, displayname + async def on_GET(self, request: SynapseRequest) -> None: + client_redirect_url = parse_string(request, "redirectUrl", required=True) + ticket = parse_string(request, "ticket", required=True) + await self._cas_handler.handle_ticket_request( + request, client_redirect_url, ticket ) - def parse_cas_response(self, cas_response_body): - user = None - attributes = {} - try: - root = ET.fromstring(cas_response_body) - if not root.tag.endswith("serviceResponse"): - raise Exception("root of CAS response is not serviceResponse") - success = root[0].tag.endswith("authenticationSuccess") - for child in root[0]: - if child.tag.endswith("user"): - user = child.text - if child.tag.endswith("attributes"): - for attribute in child: - # ElementTree library expands the namespace in - # attribute tags to the full URL of the namespace. - # We don't care about namespace here and it will always - # be encased in curly braces, so we remove them. - tag = attribute.tag - if "}" in tag: - tag = tag.split("}")[1] - attributes[tag] = attribute.text - if user is None: - raise Exception("CAS response does not contain user") - except Exception: - logger.exception("Error parsing CAS response") - raise LoginError(401, "Invalid CAS response", errcode=Codes.UNAUTHORIZED) - if not success: - raise LoginError( - 401, "Unsuccessful CAS response", errcode=Codes.UNAUTHORIZED - ) - return user, attributes - class SAMLRedirectServlet(BaseSSORedirectServlet): PATTERNS = client_patterns("/login/sso/redirect", v1=True) @@ -533,65 +449,10 @@ class SAMLRedirectServlet(BaseSSORedirectServlet): def __init__(self, hs): self._saml_handler = hs.get_saml_handler() - def get_sso_url(self, client_redirect_url): + def get_sso_url(self, client_redirect_url: bytes) -> bytes: return self._saml_handler.handle_redirect_request(client_redirect_url) -class SSOAuthHandler(object): - """ - Utility class for Resources and Servlets which handle the response from a SSO - service - - Args: - hs (synapse.server.HomeServer) - """ - - def __init__(self, hs): - self._hostname = hs.hostname - self._auth_handler = hs.get_auth_handler() - self._registration_handler = hs.get_registration_handler() - self._macaroon_gen = hs.get_macaroon_generator() - - # cast to tuple for use with str.startswith - self._whitelisted_sso_clients = tuple(hs.config.sso_client_whitelist) - - async def on_successful_auth( - self, username, request, client_redirect_url, user_display_name=None - ): - """Called once the user has successfully authenticated with the SSO. - - Registers the user if necessary, and then returns a redirect (with - a login token) to the client. - - Args: - username (unicode|bytes): the remote user id. We'll map this onto - something sane for a MXID localpath. - - request (SynapseRequest): the incoming request from the browser. We'll - respond to it with a redirect. - - client_redirect_url (unicode): the redirect_url the client gave us when - it first started the process. - - user_display_name (unicode|None): if set, and we have to register a new user, - we will set their displayname to this. - - Returns: - Deferred[none]: Completes once we have handled the request. - """ - localpart = map_username_to_mxid_localpart(username) - user_id = UserID(localpart, self._hostname).to_string() - registered_user_id = await self._auth_handler.check_user_exists(user_id) - if not registered_user_id: - registered_user_id = await self._registration_handler.register_user( - localpart=localpart, default_display_name=user_display_name - ) - - self._auth_handler.complete_sso_login( - registered_user_id, request, client_redirect_url - ) - - def register_servlets(hs, http_server): LoginRestServlet(hs).register(http_server) if hs.config.cas_enabled: diff --git a/synapse/server.py b/synapse/server.py index d0d80e8ac5..c7ca2bda0d 100644 --- a/synapse/server.py +++ b/synapse/server.py @@ -56,6 +56,7 @@ from synapse.handlers.account_validity import AccountValidityHandler from synapse.handlers.acme import AcmeHandler from synapse.handlers.appservice import ApplicationServicesHandler from synapse.handlers.auth import AuthHandler, MacaroonGenerator +from synapse.handlers.cas_handler import CasHandler from synapse.handlers.deactivate_account import DeactivateAccountHandler from synapse.handlers.device import DeviceHandler, DeviceWorkerHandler from synapse.handlers.devicemessage import DeviceMessageHandler @@ -198,6 +199,7 @@ class HomeServer(object): "sendmail", "registration_handler", "account_validity_handler", + "cas_handler", "saml_handler", "event_client_serializer", "password_policy_handler", @@ -529,6 +531,9 @@ class HomeServer(object): def build_account_validity_handler(self): return AccountValidityHandler(self) + def build_cas_handler(self): + return CasHandler(self) + def build_saml_handler(self): from synapse.handlers.saml_handler import SamlHandler diff --git a/tox.ini b/tox.ini index 8e3f09e638..a79fc93b57 100644 --- a/tox.ini +++ b/tox.ini @@ -186,6 +186,7 @@ commands = mypy \ synapse/federation/sender \ synapse/federation/transport \ synapse/handlers/auth.py \ + synapse/handlers/cas_handler.py \ synapse/handlers/directory.py \ synapse/handlers/presence.py \ synapse/handlers/sync.py \ |