.. 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. =================================== Configuring Keystone for Federation =================================== ----------- Definitions ----------- * `Service Provider (SP)`: provides a service to an end-user. * `Identity Provider (IdP)`: service that stores information about users and groups. * `SAML assertion`: contains information about a user as provided by an IdP. ----------------------------------- Keystone as a Service Provider (SP) ----------------------------------- .. NOTE:: This feature is considered stable and supported as of the Juno release. Prerequisites ------------- This approach to federation supports keystone as a Service Provider, consuming identity properties issued by an external Identity Provider, such as SAML assertions or OpenID Connect claims. Federated users are not mirrored in the keystone identity backend (for example, using the SQL driver). The external Identity Provider is responsible for authenticating users, and communicates the result of authentication to keystone using identity properties. Keystone maps these values to keystone user groups and assignments created in keystone. The following configuration steps were performed on a machine running Ubuntu 12.04 and Apache 2.2.22. To enable federation, you'll need to: 1. Run keystone under Apache, rather than using ``keystone-all``. 2. Configure Apache to use a federation capable authentication method. 3. Configure ``federation`` in keystone. Configure Apache to use a federation capable authentication method ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ There is currently support for two major federation protocols: * SAML - Keystone supports the following implementations: * Shibboleth - see `Setup Shibboleth`_. * Mellon - see `Setup Mellon`_. * OpenID Connect - see `Setup OpenID Connect`_. .. _`Setup Shibboleth`: federation/shibboleth.html .. _`Setup OpenID Connect`: federation/openidc.html .. _`Setup Mellon`: federation/mellon.html Configure keystone and Horizon for Single Sign-On ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * To configure horizon to access a federated keystone, follow the steps outlined at: `Keystone Federation and Horizon`_. .. _`Keystone Federation and Horizon`: federation/websso.html Configuring Federation in Keystone ----------------------------------- Now that the Identity Provider and keystone are communicating we can start to configure ``federation``. 1. Configure authentication drivers in ``keystone.conf`` 2. Add local keystone groups and roles 3. Add Identity Provider(s), Mapping(s), and Protocol(s) Configure authentication drivers in ``keystone.conf`` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. NOTE:: ``saml2`` has been deprecated as of the Mitaka release. Support for the ``saml2`` wrapper will be removed as of the "O" release. The recommended authentication method is ``mapped``, which supports ``saml2``. Add the authentication methods to the ``[auth]`` section in ``keystone.conf``. Names should be equal to protocol names added via Identity API v3. Here we use examples ``mapped`` and ``openid``. .. code-block:: bash [auth] methods = external,password,token,mapped,openid Create keystone groups and assign roles ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ As mentioned earlier, no new users will be added to the Identity backend, but the Identity Service requires group-based role assignments to authorize federated users. The federation mapping function will map the user into local Identity Service groups objects, and hence to local role assignments. Thus, it is required to create the necessary Identity Service groups that correspond to the Identity Provider's groups; additionally, these groups should be assigned roles on one or more projects or domains. You may be interested in more information on `group management `_ and `role assignments `_, both of which are exposed to the CLI via `python-openstackclient `_. Add Identity Provider(s), Mapping(s), and Protocol(s) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To utilize federation the following must be created in the Identity Service: * Identity Provider * Mapping * Protocol More information on ``federation in keystone`` can be found `here `__. ~~~~~~~~~~~~~~~~~ Identity Provider ~~~~~~~~~~~~~~~~~ Create an Identity Provider object in keystone, which represents the Identity Provider we will use to authenticate end users. More information on identity providers can be found `here `__. ~~~~~~~ Mapping ~~~~~~~ A mapping is a list of rules. The only Identity API objects that will support mapping are groups and users. Mapping adds a set of rules to map federation protocol attributes to Identity API objects. There are many different ways to setup as well as combine these rules. More information on rules can be found on the :doc:`mapping_combinations` page. An Identity Provider has exactly one mapping specified per protocol. Mapping objects can be used multiple times by different combinations of Identity Provider and Protocol. More information on mapping can be found `here `__. ~~~~~~~~ Protocol ~~~~~~~~ A protocol contains information that dictates which Mapping rules to use for an incoming request made by an IdP. An IdP may have multiple supported protocols. Add `Protocol object `__ and specify the mapping id you want to use with the combination of the IdP and Protocol. Performing federated authentication ----------------------------------- 1. Authenticate externally and generate an unscoped token in keystone 2. Determine accessible resources 3. Get a scoped token Get an unscoped token ~~~~~~~~~~~~~~~~~~~~~ Unlike other authentication methods in the Identity Service, the user does not issue an HTTP POST request with authentication data in the request body. To start federated authentication a user must access the dedicated URL with Identity Provider's and Protocol's identifiers stored within a protected URL. The URL has a format of: ``/v3/OS-FEDERATION/identity_providers/{idp_id}/protocols/{protocol_id}/auth``. In this instance we follow a standard SAML2 authentication procedure, that is, the user will be redirected to the Identity Provider's authentication webpage and be prompted for credentials. After successfully authenticating the user will be redirected to the Service Provider's endpoint. If using a web browser, a token will be returned in XML format. In the returned unscoped token, a list of Identity Service groups the user belongs to will be included. More information on getting an unscoped token can be found `here `__. ~~~~~~~~~~~~ Example cURL ~~~~~~~~~~~~ Note that the request does not include a body. The following url would be considered protected by ``mod_shib`` and Apache, as such a request made to the URL would be redirected to the Identity Provider, to start the SAML authentication procedure. .. code-block:: bash $ curl -X GET -D - http://localhost:5000/v3/OS-FEDERATION/identity_providers/{idp_id}/protocols/{protocol_id}/auth Determine accessible resources ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ By using the previously returned token, the user can issue requests to the list projects and domains that are accessible. * List projects a federated user can access: ``GET /OS-FEDERATION/projects`` * List domains a federated user can access: ``GET /OS-FEDERATION/domains`` More information on listing resources can be found `here `__. ~~~~~~~~~~~~ Example cURL ~~~~~~~~~~~~ .. code-block:: bash $ curl -X GET -H "X-Auth-Token: " http://localhost:5000/v3/OS-FEDERATION/projects or .. code-block:: bash $ curl -X GET -H "X-Auth-Token: " http://localhost:5000/v3/OS-FEDERATION/domains Get a scoped token ~~~~~~~~~~~~~~~~~~ A federated user may request a scoped token, by using the unscoped token. A project or domain may be specified by either ``id`` or ``name``. An ``id`` is sufficient to uniquely identify a project or domain. More information on getting a scoped token can be found `here `__. ~~~~~~~~~~~~ Example cURL ~~~~~~~~~~~~ .. code-block:: bash $ curl -X POST -H "Content-Type: application/json" -d '{"auth":{"identity":{"methods":["mapped"],"saml2":{"id":""}},"scope":{"project":{"domain": {"name": "Default"},"name":"service"}}}}' -D - http://localhost:5000/v3/auth/tokens -------------------------------------- Keystone as an Identity Provider (IdP) -------------------------------------- .. NOTE:: This feature is experimental and unsupported in Juno (with several issues that will not be backported). These issues have been fixed and this feature is considered stable and supported as of the Kilo release. .. NOTE:: This feature requires installation of the xmlsec1 tool via your distribution packaging system (for instance apt or yum) Example for apt: .. code-block:: bash $ apt-get install xmlsec1 Configuration Options --------------------- There are certain settings in ``keystone.conf`` that must be setup, prior to attempting to federate multiple keystone deployments. Within ``keystone.conf``, assign values to the ``[saml]`` related fields, for example: .. code-block:: ini [saml] certfile=/etc/keystone/ssl/certs/ca.pem keyfile=/etc/keystone/ssl/private/cakey.pem idp_entity_id=https://keystone.example.com/v3/OS-FEDERATION/saml2/idp idp_sso_endpoint=https://keystone.example.com/v3/OS-FEDERATION/saml2/sso idp_metadata_path=/etc/keystone/saml2_idp_metadata.xml Though not necessary, the follow Organization configuration options should also be setup. It is recommended that these values be URL safe. .. code-block:: ini idp_organization_name=example_company idp_organization_display_name=Example Corp. idp_organization_url=example.com As with the Organization options, the Contact options, are not necessary, but it's advisable to set these values too. .. code-block:: ini idp_contact_company=example_company idp_contact_name=John idp_contact_surname=Smith idp_contact_email=jsmith@example.com idp_contact_telephone=555-55-5555 idp_contact_type=technical Generate Metadata ----------------- In order to create a trust between the IdP and SP, metadata must be exchanged. To create metadata for your keystone IdP, run the ``keystone-manage`` command and pipe the output to a file. For example: .. code-block:: bash $ keystone-manage saml_idp_metadata > /etc/keystone/saml2_idp_metadata.xml .. NOTE:: The file location should match the value of the configuration option ``idp_metadata_path`` that was assigned in the previous section. Create a Service Provider (SP) ------------------------------ In this example we are creating a new Service Provider with an ID of ``BETA``, a ``sp_url`` of ``http://beta.example.com/Shibboleth.sso/SAML2/ECP`` and a ``auth_url`` of ``http://beta.example.com:5000/v3/OS-FEDERATION/identity_providers/beta/protocols/saml2/auth`` . The ``sp_url`` will be used when creating a SAML assertion for ``BETA`` and signed by the current keystone IdP. The ``auth_url`` is used to retrieve the token for ``BETA`` once the SAML assertion is sent. Although the ``enabled`` field is optional we are passing it set to ``true`` otherwise it will be set to ``false`` by default. .. code-block:: bash $ curl -s -X PUT \ -H "X-Auth-Token: $OS_TOKEN" \ -H "Content-Type: application/json" \ -d '{"service_provider": {"auth_url": "http://beta.example.com:5000/v3/OS-FEDERATION/identity_providers/beta/protocols/saml2/auth", "sp_url": "https://example.com:5000/Shibboleth.sso/SAML2/ECP", "enabled": true}}' \ http://localhost:5000/v3/OS-FEDERATION/service_providers/BETA | python -mjson.tool Testing it all out ------------------ Lastly, if a scoped token and a Service Provider scope are presented to the local keystone, the result will be a full ECP wrapped SAML Assertion, specifically intended for the Service Provider keystone. .. NOTE:: ECP stands for Enhanced Client or Proxy, an extension from the SAML2 protocol used in non-browser interfaces, like in the following example with cURL. .. code-block:: bash $ curl -s -X POST \ -H "Content-Type: application/json" \ -d '{"auth": {"scope": {"service_provider": {"id": "BETA"}}, "identity": {"token": {"id": "d793d935b9c343f783955cf39ee7dc3c"}, "methods": ["token"]}}}' \ http://localhost:5000/v3/auth/OS-FEDERATION/saml2/ecp .. NOTE:: Use URL http://localhost:5000/v3/auth/OS-FEDERATION/saml2 to request for pure SAML Assertions. At this point the ECP wrapped SAML Assertion can be sent to the Service Provider keystone using the provided ``auth_url`` in the ``X-Auth-Url`` header present in the response containing the Assertion, and a valid OpenStack token, issued by a Service Provider keystone, will be returned.