django-simple-sso
=================
The latest version of this package supports:
* Django >= 1.11
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Django Simple SSO Specification (DRAFT)
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Terminology
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Server
======
The server is a Django website that holds all the user information and
authenticates users.
Client
======
The client is a Django website that provides login via SSO using the **Server**.
It does not hold any user information.
Key
===
A unique key identifying a **Client**. This key can be made public.
Secret
======
A secret key shared between the **Server** and a single **Client**. This secret
should never be shared with anyone other than the **Server** and **Client** and
must not be transferred unencrypted.
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Workflow
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#. User wants to log into a **Client** by clicking a "Login" button. The
initially requested URL can be passed using the ``next`` GET parameter.
#. The **Client**'s Python code does a HTTP request to the **Server** to request a
authentication token, this is called the **Request Token Request**.
#. The **Server** returns a **Request Token**.
#. The **Client** redirects the User to a view on the **Server** using the
**Request Token**, this is the **Authorization Request**.
#. If the user is not logged in the the **Server**, they are prompted to log in.
#. The user is redirected to the **Client** including the **Request Token** and a
**Auth Token**, this is the ``Authentication Request``.
#. The **Client**'s Python code does a HTTP request to the **Server** to verify the
**Auth Token**, this is called the **Auth Token Verification Request**.
#. If the **Auth Token** is valid, the **Server** returns a serialized Django User
object.
#. The **Client** logs the user in using the Django User recieved from the **Server**.
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Requests
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General
=======
All requests have a ``signature`` and ``key`` parameter, see **Security**.
Request Token Request
=====================
* Client: Python
* Target: **Server**
* Method: GET
* Extra Parameters: None
* Responses:
* ``200``: Everything went fine, the body of the response is a url encoded
query string containing with the ``request_token`` key holding the
**Request Token** as well as the ``signature``.
* ``400``: Bad request (missing GET parameters)
* ``403``: Forbidden (invalid signature)
Authorization Request
=====================
* Client: Browser (User)
* Target: **Server**
* Method: GET
* Extra Parameters:
* ``request_token``
* Responses:
* ``200``: Everything okay, prompt user to log in or continue.
* ``400``: Bad request (missing GET parameter).
* ``403``: Forbidden (invalid **Request Token**).
Authentication Request
======================
* Client: Browser (User)
* Target: **Client**
* Method: GET
* Extra Parameters:
* ``request_token``: The **Request Token** returned by the
**Request Token Request**.
* ``auth_token``: The **Auth Token** generated by the **Authorization Request**.
* Responses:
* ``200``: Everything went fine, the user is now logged in.
* ``400``: Bad request (missing GET parameters).
* ``403``: Forbidden (invalid **Request Token**).
Auth Token Verification Request
===============================
* Client: Python
* Target: **Server**
* Method: GET
* Extra Parameters:
* ``auth_token``: The **Auth Token** obtained by the **Authentication Request**.
* Responses:
* ``200``: Everything went fine, the body of the response is a url encoded
query string containing the ``user`` key which is the JSON serialized
representation of the Django user to create as well as the ``signature``.
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Security
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Every request is signed using HMAC-SHA256. The signature is in the ``signature``
parameter. The signature message is the urlencoded, alphabetically ordered
query string. The signature key is the **Secret** of the **Client**. To verify
the signature the ``key`` paramater holding the **key** of the **Client** is
also sent with every request from the **Client** to the **Server**.
Example
=======
GET Request with the GET parameters ``key=bundle123`` and the private key
``secret key``: ``fbf6396d0fc40d563e2be3c861f7eb5a1b821b76c2ac943d40a7a63b288619a9``
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The User object
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The User object returned by a successful **Auth Token Verification Request**
does not contain all the information about the Django User, in particular, it
does not contain the password.
The user object contains must contain at least the following data:
* ``username``: The unique username of this user.
* ``email``: The email of this user.
* ``first_name``: The first name of this user, this field is required, but may
be empty.
* ``last_name``: The last name of this user, this field is required, but may
be empty.
* ``is_staff``: Can this user access the Django admin on the **Client**?
* ``is_superuser``: Does this user have superuser access to the **Client**?
* ``is_active``: Is the user active?
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Implementation
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On the server
=============
* Add ``simple_sso.sso_server`` to ``INSTALLED_APPS``.
* Create an instance (potentially of a subclass) of
``simple_sso.sso_server.server.Server`` and include the return value of the
``get_urls`` method on that instance into your url patterns.
On the client
=============
* Create a new instance of ``simple_sso.sso_server.models.Consumer`` on the
**Server**.
* Add the ``SIMPLE_SSO_SECRET`` and ``SIMPLE_SSO_KEY`` settings as provided by
the **Server**'s ``simple_sso.sso_server.models.Client`` model.
* Add the ``SIMPLE_SSO_SERVER`` setting which is the absolute URL pointing to
the root where the ``simple_sso.sso_server.urls`` where include on the
**Server**.
* Add the ``simple_sso.sso_client.urls`` patterns somewhere on the client.