You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
114 lines
4.8 KiB
ReStructuredText
114 lines
4.8 KiB
ReStructuredText
.. Copyright 2019 New Vector Ltd
|
|
..
|
|
.. 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.
|
|
|
|
SSO client login
|
|
================
|
|
|
|
.. _module:sso_login:
|
|
|
|
Single Sign-On (SSO) is a generic term which refers to protocols which allow
|
|
users to log into applications via a single web-based authentication portal.
|
|
Examples include "Central Authentication Service" (CAS) and SAML.
|
|
|
|
An overview of the process, as used in Matrix, is as follows:
|
|
|
|
1. The Matrix client instructs the user's browser to navigate to the
|
|
|/login/sso/redirect|_ endpoint on the user's homeserver.
|
|
|
|
2. The homeserver responds with an HTTP redirect to the SSO user interface,
|
|
which the browser follows.
|
|
|
|
3. The SSO system authenticates the user.
|
|
|
|
4. The SSO server and the homeserver interact to verify the user's identity
|
|
and other authentication information, potentially using a number of redirects.
|
|
|
|
5. The browser is directed to the ``redirectUrl`` provided by the client with
|
|
a ``loginToken`` query parameter for the client to log in with.
|
|
|
|
.. Note::
|
|
In the older `r0.4.0 version <https://matrix.org/docs/spec/client_server/r0.4.0.html#cas-based-client-login>`_
|
|
of this specification it was possible to authenticate via CAS when the server
|
|
provides a ``m.login.cas`` login flow. This specification deprecates the use
|
|
of ``m.login.cas`` to instead prefer ``m.login.sso``, which is the same process
|
|
with the only change being which redirect endpoint to use: for ``m.login.cas``, use
|
|
``/cas/redirect`` and for ``m.login.sso`` use ``/sso/redirect`` (described below).
|
|
The endpoints are otherwise the same.
|
|
|
|
Client behaviour
|
|
----------------
|
|
|
|
The client starts the process by instructing the browser to navigate to
|
|
|/login/sso/redirect|_ with an appropriate ``redirectUrl``. Once authentication
|
|
is successful, the browser will be redirected to that ``redirectUrl``.
|
|
|
|
.. TODO-spec
|
|
|
|
Should we recommend some sort of CSRF protection here (specifically, we
|
|
should guard against people accidentally logging in by sending them a link
|
|
to ``/login/sso/redirect``.
|
|
|
|
Maybe we should recommend that the ``redirectUrl`` should contain a CSRF
|
|
token which the client should then check before sending the login token to
|
|
``/login``?
|
|
|
|
{{sso_login_redirect_cs_http_api}}
|
|
|
|
Server behaviour
|
|
----------------
|
|
|
|
The URI for the SSO system to be used should be configured on the server by the
|
|
server administrator. The server is expected to set up any endpoints required to
|
|
interact with that SSO system. For example, for CAS authentication the homeserver
|
|
should provide a means for the administrator to configure where the CAS server is
|
|
and the REST endpoints which consume the ticket. A good reference for how CAS could
|
|
be implemented is available in the older `r0.4.0 version <https://matrix.org/docs/spec/client_server/r0.4.0.html#cas-based-client-login>`_
|
|
of this specification.
|
|
|
|
Handling the redirect endpoint
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
When responding to the ``/login/sso/redirect`` endpoint, the server must
|
|
generate a URI for the SSO login page with any appropriate parameters.
|
|
|
|
.. TODO-spec:
|
|
|
|
It might be nice if the server did some validation of the ``redirectUrl``
|
|
parameter, so that we could check that aren't going to redirect to a non-TLS
|
|
endpoint, and to give more meaningful errors in the case of
|
|
faulty/poorly-configured clients.
|
|
|
|
Handling the authentication endpoint
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Once the homeserver has verified the user's identity with the SSO system, it
|
|
MUST map the user ID to a valid `Matrix user identifier <../index.html#user-identifiers>`_.
|
|
The guidance in `Mapping from other character sets
|
|
<../index.html#mapping-from-other-character-sets>`_ may be useful.
|
|
|
|
If the generated user identifier represents a new user, it should be registered
|
|
as a new user.
|
|
|
|
Finally, the server should generate a short-term login token. The generated
|
|
token should be a macaroon, suitable for use with the ``m.login.token`` type of
|
|
the |/login|_ API, and `token-based interactive login <#token-based>`_. The
|
|
lifetime of this token SHOULD be limited to around five seconds. This token is
|
|
given to the client via the ``loginToken`` query parameter previously mentioned.
|
|
|
|
|
|
.. |/login| replace:: ``/login``
|
|
.. _/login: #post-matrix-client-%CLIENT_MAJOR_VERSION%-login
|
|
.. |/login/sso/redirect| replace:: ``/login/sso/redirect``
|
|
.. _/login/sso/redirect: #get-matrix-client-%CLIENT_MAJOR_VERSION%-login-sso-redirect
|