229 lines
8.7 KiB
Python
229 lines
8.7 KiB
Python
# -*- 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 urllib
|
|
from typing import Dict, Optional, Tuple
|
|
from xml.etree import ElementTree as ET
|
|
|
|
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.hs = 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, args: Dict[str, str]) -> str:
|
|
"""
|
|
Generates a value to use as the "service" parameter when redirecting or
|
|
querying the CAS service.
|
|
|
|
Args:
|
|
args: Additional arguments to include in the final redirect URL.
|
|
|
|
Returns:
|
|
The URL to use as a "service" parameter.
|
|
"""
|
|
return "%s%s?%s" % (
|
|
self._cas_service_url,
|
|
"/_matrix/client/r0/login/cas/ticket",
|
|
urllib.parse.urlencode(args),
|
|
)
|
|
|
|
async def _validate_ticket(
|
|
self, ticket: str, service_args: Dict[str, str]
|
|
) -> Tuple[str, Optional[str]]:
|
|
"""
|
|
Validate a CAS ticket with the server, parse the response, and return the user and display name.
|
|
|
|
Args:
|
|
ticket: The CAS ticket from the client.
|
|
service_args: Additional arguments to include in the service URL.
|
|
Should be the same as those passed to `get_redirect_url`.
|
|
"""
|
|
uri = self._cas_server_url + "/proxyValidate"
|
|
args = {
|
|
"ticket": ticket,
|
|
"service": self._build_service_param(service_args),
|
|
}
|
|
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
|
|
|
|
user, attributes = self._parse_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 user, displayname
|
|
|
|
def _parse_cas_response(
|
|
self, cas_response_body: bytes
|
|
) -> 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
|
|
|
|
def get_redirect_url(self, service_args: Dict[str, str]) -> str:
|
|
"""
|
|
Generates a URL for the CAS server where the client should be redirected.
|
|
|
|
Args:
|
|
service_args: Additional arguments to include in the final redirect URL.
|
|
|
|
Returns:
|
|
The URL to redirect the client to.
|
|
"""
|
|
args = urllib.parse.urlencode(
|
|
{"service": self._build_service_param(service_args)}
|
|
)
|
|
|
|
return "%s/login?%s" % (self._cas_server_url, args)
|
|
|
|
async def handle_ticket(
|
|
self,
|
|
request: SynapseRequest,
|
|
ticket: str,
|
|
client_redirect_url: Optional[str],
|
|
session: Optional[str],
|
|
) -> None:
|
|
"""
|
|
Called once the user has successfully authenticated with the SSO.
|
|
Validates a CAS ticket sent by the client and completes the auth process.
|
|
|
|
If the user interactive authentication session is provided, marks the
|
|
UI Auth session as complete, then returns an HTML page notifying the
|
|
user they are done.
|
|
|
|
Otherwise, this registers the user if necessary, and then returns a
|
|
redirect (with a login token) to the client.
|
|
|
|
Args:
|
|
request: the incoming request from the browser. We'll
|
|
respond to it with a redirect or an HTML page.
|
|
|
|
ticket: The CAS ticket provided by the client.
|
|
|
|
client_redirect_url: the redirectUrl parameter from the `/cas/ticket` HTTP request, if given.
|
|
This should be the same as the redirectUrl from the original `/login/sso/redirect` request.
|
|
|
|
session: The session parameter from the `/cas/ticket` HTTP request, if given.
|
|
This should be the UI Auth session id.
|
|
"""
|
|
args = {}
|
|
if client_redirect_url:
|
|
args["redirectUrl"] = client_redirect_url
|
|
if session:
|
|
args["session"] = session
|
|
username, user_display_name = await self._validate_ticket(ticket, args)
|
|
|
|
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 session:
|
|
await self._auth_handler.complete_sso_ui_auth(
|
|
registered_user_id, session, request,
|
|
)
|
|
|
|
else:
|
|
if not registered_user_id:
|
|
# Pull out the user-agent and IP from the request.
|
|
user_agent = request.requestHeaders.getRawHeaders(
|
|
b"User-Agent", default=[b""]
|
|
)[0].decode("ascii", "surrogateescape")
|
|
ip_address = self.hs.get_ip_from_request(request)
|
|
|
|
registered_user_id = await self._registration_handler.register_user(
|
|
localpart=localpart,
|
|
default_display_name=user_display_name,
|
|
user_agent_ips=(user_agent, ip_address),
|
|
)
|
|
|
|
await self._auth_handler.complete_sso_login(
|
|
registered_user_id, request, client_redirect_url
|
|
)
|