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How Authentication works with MoinMoin

MoinMoin supports configurable, modular authenticators to support all sorts of builtin and 3rd party authentication methods.

You use the auth configuration value to set up a list of authenticators that are processed in exactly that order.

When an external user database is used, you do not want to recreate all users in moin manually. For this case the authenticator objects which support user profile creation/updating have a parameter autocreate. If you set it to True a new user profile will be created/updated automatically when a (new) user has passed authentication.

Presently the following authenticators are supported:

Server setup

Authentication

Authenticator class in moin

All

by moin via username/password

MoinMoin.auth.MoinAuth

by PHP session

MoinMoin.auth.php_session.PHPSessionAuth

by moin via external cookie

see contrib/auth_externalcookie/ and HelpOnAuthentication/ExternalCookie

by OpenID

MoinMoin.auth.openidrp.OpenIDAuth

OpenID verification by http://botbouncer.com/

MoinMoin.auth.botbouncer.BotBouncer

by moin via LDAP

MoinMoin.auth.ldap_login.LDAPAuth

by moin via a remote moin wiki

MoinMoin.auth.interwiki - still experimental

by moin configuration, fixed username

MoinMoin.auth.GivenAuth

any Web Server setting REMOTE_USER

e.g. for HTTP Basic, HTTP Digest, SSPI (aka NTLM) or LDAP auth

MoinMoin.auth.GivenAuth

Apache+SSL

by Apache via SSL client certificate

MoinMoin.auth.sslclientcert.SSLClientCertAuth

Other pseudo-authenticators - These are not strictly authenticators, as they don't authenticate users, but use auth information for other purposes:

1. Shipped plugins

1.1. MoinAuth (default)

This is the default auth list moin uses (so if you just want that, you don't need to configure it).

   1     from MoinMoin.auth import MoinAuth
   2     auth = [MoinAuth()]

1.2. Given authentication

1.2.1. given by REMOTE_USER environment variable

Webservers (like e.g. Apache) often support all sorts of authentication plugins (e.g. HTTP basic auth). If the webserver is configured for authentication, it handles authentication before moin gets called. When visiting a resource requiring authentication, you get queried for username/password by a dialog box of your browser. When you submit, 2 things can happen:

Moin's GivenAuth authenticator will, by default, just try to log in the user with the username it recieved from REMOTE_USER.

To activate usage of REMOTE_USER for authentication you have to add following lines to wikiconfig.py:

   1     from MoinMoin.auth import GivenAuth
   2     auth = [GivenAuth(autocreate=True)]

1.2.2. given by other environment variable

Instead of reading the username from REMOTE_USER, moin can also read it from some other environment variable:

   1     from MoinMoin.auth import GivenAuth
   2     auth = [GivenAuth(env_var='WHATEVER', autocreate=True)]

1.2.3. decoding of the user name

REMOTE_USER (or whatever you specify as env_var) is a encoded string and needs to be decoded to unicode. If you don't specify the coding, moin will try 'utf-8' and 'latin-1' (in that order). For non-ASCII characters, this might lead to incorrect results if another coding was used by the web server.

If it fails, you can specify the coding manually:

   1     auth = [GivenAuth(env_var='WHATEVER', autocreate=True, coding='cp850')]

1.2.4. transformation of the user name

Sometimes the user name we receive in REMOTE_USER needs some transformation, so it can sanely be used in the wiki.

GivenAuth has some flags to support some standard transformations, enable whatever you like (give True - the default is all False, meaning disabled transformation):

Flag

Input

Output

strip_maildomain

joe@example.org

joe

strip_windomain

DOMAIN\joe

joe

titlecase

joe doe

Joe Doe

remove_blanks

Joe Doe

JoeDoe

(!) The transformations (if enabled) will happen in the order shown.

For example, for some windows domain environments, this might make sense:

   1     auth = [GivenAuth(autocreate=True, strip_windomain=True, titlecase=True, remove_blanks=True)]

1.2.5. fixed user given by configuration

You can also hardcode a username into your configuration:

   1     from MoinMoin.auth import GivenAuth
   2     auth = [GivenAuth(user_name=u'Joe Doe', autocreate=True)]

Everyone and everything accessing the wiki will now be logged in as user Joe Doe automatically.

1.3. SSL client certification authentication

To activate authentication via SSL client certificates you have to add following lines to wikiconfig.py:

   1     from MoinMoin.auth.sslclientcert import SSLClientCertAuth
   2     auth = [SSLClientCertAuth()]

SSL client certification authentication must be used with a web server like Apache that handles the SSL bits and just presents a few environment variables to Moin.

The SSLClientCertAuth authenticator has a few parameters that you pass to the constructor (example below):

Parameter

Default

Meaning

authorities

None

a list of authorities that are accepted, or None to accept all

email_key

True

indicates whether the email in the certificate should be used to find the Moin user

name_key

True

indiciates whether the name in the certificate should be used to find the Moin user

use_email

False

if set to True, the account email cannot be changed and is forced to the one given in the certificate

use_name

False

if set to True, the account name cannot be changed and is forced to the one given in the certificate

autocreate

False

if set to True, automatically create moin user profiles

For example, to accept only certificates that Apache has verified and that are signed by a certain authority, use:

   1     from MoinMoin.auth.sslclientcert import SSLClientCertAuth
   2     auth = [SSLClientCertAuth(authorities=['my.authority.tld'])]

or similar.

1.4. PHP session

To activate Single-Sign-On integration with PHP applications, use this module. It reads PHP session files and therefore directly integrates with existing PHP authentication systems.

To use this module, use the following lines of code in your configuration:

   1     from MoinMoin.auth.php_session import PHPSessionAuth
   2     auth = [PHPSessionAuth()]

PHPSessionAuth has the following parameters:

   1     PHPSessionAuth(apps=['egw'], s_path="/tmp", s_prefix="sess_")

The only supported PHP application is eGroupware 1.2 currently. But it should be fairly easy to add a few lines of code that extract the necessary information from the PHP session, if you do that, please open a feature request with a patch.

1.5. OpenID (with BotBouncer)

The OpenID authentication plugin allows users to sign in using their OpenID and connect that OpenID to a new or existing Moin account. To allow users to sign in with OpenID, add the plugin to the auth list, or to require OpenID with http://botbouncer.com/ verification use:

   1     from MoinMoin.auth.openidrp import OpenIDAuth
   2     from MoinMoin.auth.botbouncer import BotBouncer
   3     auth = [OpenIDAuth(), BotBouncer("your-botbouncer-API-key")]

OpenID authentication requires anonymous sessions, set the first part of the cookie_lifetime tuple to anything bigger than zero (like cookie_lifetime = (2,12)). See HelpOnConfiguration for more details on the value. For OpenID, very little time should be sufficient.

1.5.1. Advanced OpenID RP configuration

The OpenID RP code can also be configured for two use cases:

  1. You can force a specific provider to be used, there are two ways to achieve this:
    • Simply configure the OpenIDAuth authenticator like this:

      auth = [OpenIDAuth(forced_service='http://myopenid.com/'), ]
    • Create an OpenIDServiceEndpoint object and use that for the forced_service parameter:

      fs = OpenIDServiceEndpoint()
      fs.type_uris = OPENID_2_0_TYPE
      fs.server_url = 'http://localhost:8000/openidserver'
      fs.claimed_id = 'http://specs.openid.net/auth/2.0/identifier_select'
      
      auth = [OpenIDAuth(forced_service=fs), ]
    In the latter case, no discovery needs to be done.
  2. You can specify functions to be called in various steps of the OpenID authentication process to, for example, implement Attribute Exchange. For now, this is not documented here, you'll have to look at the file MoinMoin/auth/openidrp.py.

1.6. LDAP based user authentication

The LDAP authenticator of Moin enables single-sign-on (SSO) - assuming you already have a LDAP directory with your users, passwords, email adresses. On Linux this could be some OpenLDAP server, on a Windows server (usually the domain controller) this is called "Active Directory" (short: AD).

It works like this:

1.6.1. LDAP auth installation / configuration

You need to install python-ldap module (and everything it depends on, see its documentation).

You need an LDAP or AD server. :)

See wiki/config/more_samples/ldap_wikiconfig_snippet.py in your moin dist archive for a snippet you can use in your wiki config.

(!) Please also read the README file in that directory.

1.6.2. LDAP auth Problems?

MoinMoin support does not know your LDAP server setup, so please follow these steps before asking for help:

/!\ Only ask MoinMoin support if you successfully used ldapsearch (or some similar tool) and you double checked your wiki config and it does still not work with moin.

1.7. XMLRPC auth

   1 import xmlrpclib
   2 
   3 name = "TestUser"
   4 password = "secret"
   5 wikiurl = "http://localhost:8080/"
   6 
   7 homewiki = xmlrpclib.ServerProxy(wikiurl + "?action=xmlrpc2", allow_none=True)
   8 auth_token = homewiki.getAuthToken(name, password)
   9 
  10 mc = xmlrpclib.MultiCall(homewiki)
  11 mc.applyAuthToken(auth_token)
  12 # you can add more xmlrpc method calls to the multicall here,
  13 # they will run authenticated as user <name>.
  14 result = mc()

2. Combining multiple authenticators

For combining e.g. SSL client certificate and username/password authentication, your wikiconfig.py might contain:

   1     from MoinMoin.auth import MoinAuth
   2     from MoinMoin.auth.sslclientcert import SSLClientCertAuth
   3     auth = [SSLClientCertAuth(), MoinAuth()]

In that case, any client certificates that the user provides will be used to log him on, but if they do not provide one they still have the option of logging on with their username/password.

3. Writing your own authenticator

See the commented config file fragment contrib/auth_externalcookie/ and MoinMoin/auth/*.py in your moin distribution archive for examples of how to do authentication. Also, the docstring in MoinMoin/auth/__init__.py contains an explanation of what can be done and how it is achieved.

Authenticators can


2012-07-01 04:09