shibboleth_session_auth

Simplistic Shibboleth integration for Django sessions

This is a very simple way of allowing users to be authenticated via Shibboleth
but to be a part of Django groups and users. This is accomplished by using
Apache mod_shib to protect the provided view. If the user is able to
authenticate then we extract certain details from the data provided by
Shibboleth. The view will create Django Users and Groups as necessary.

Apache Config

This code has only been tested with mod_shib for Apache.

Here’s the config we use:

<Location /shibboleth-sso></Location>
  AuthType shibboleth
  ShibCompatWith24 On
  ShibRequestSetting requireSession true
  Require shib-attr member staff
/Location>

You may want to tweak or remove the Require line depending on your needs.
As it is, it requires users to be a member of group staff in order to be
able to authenticate.

Django Setup

You’ll need to add an entry in your urls.py, similar to this:

from shibboleth_session_auth.views import shibboleth_session_auth
urlpatterns += [
    url(r'^shibboleth-sso/', shibboleth_session_auth, name="esnet-sso"),
]

Note that we use shibboleth-sso both here and in the Apache config.

Django Settings

SHIBBOLETH_SESSION_AUTH = {
    'IDP_ATTRIBUTE': 'Shib-Identity-Provider',
    'AUTHORIZED_IDPS': [
        'https://${YOUR_IDP}/idp/shibboleth',
    ],
    #
    # note that we use Apache environment variables directly rather than the
    # HTTP_xxx variables which are derived from the HTTP request headers.
    # The HTTP_xxx variety is vulnerable to potential spoofing
    #
    'USER_ATTRIBUTES': [
        ('uid', 'username', True),
        ('mail', 'email', True),
        ('givenName', 'first_name', False),
        ('sn', 'last_name', False),
    ],
    'GROUP_ATTRIBUTE': 'member',
    'GROUPS_BY_IDP': {},
    'DJANGO_STAFF_GROUP': 'webadmin',
}

IDP_ATTRIBUTE defines which Apache environment variable carries the name of
the IdP.

AUTHORIZED_IDPS is a list of IdPs that we trust. The full URL may vary for
your setup — please check this with whomever runs your IdP..

USER_ATTRIBUTES a list of tuples which are used to map from the attribute
names provided by the IdP to fields to be used with the Django User model. The
format is (idp_attribute, django_model_attribute, required).

GROUP_ATTRIBUTE is the name used by the IdP to provide group membership.
The user will be added to each group listed in the group attribute. If the
group does not already exist it will be created. Groups are assumed to be
separated by a semicolon (;) in the data provided by the IdP.

GROUPS_BY_IDP this is a dictionary mapping an IdP (from AUTHORIZED_IDPS)
to a list of groups. If the user is authenticated to the named IdP then
the user will be added to each of the groups, creating the groups as necessary.

DJANGO_STAFF_GROUP is the name of the group presented by the IdP that will
be used to determine if the user has the is_staff bit set or not.

We assume the the IdP is the source of truth for groups and for whether or not
a user should have Django staff privileges. This means that the set of groups
the user will be a member of will be exactly the set of groups that the IdP
sends. This also means that if the user is no longer a member of
DJANGO_STAFF_GROUP that they will lose their staff privileges.