Extension:CentralAuth

MediaWiki extensions manual - list

CentralAuth Release status: stable
Implementation	User identity, Database, Special page, API
Description	Allows to merge accounts into global accounts
Author(s)	Brion Vibber
MediaWiki	1.11+
License	GPL
Download	Download snapshot (Git master) Git [?]: repo summary tree code changes
Parameters $wgCentralAuthDatabase $wgCentralAuthAutoNew $wgCentralAuthAutoMigrate $wgCentralAuthStrict $wgCentralAuthDryRun $wgCentralAuthCookies $wgCentralAuthCookieDomain $wgCentralAuthCookiePrefix $wgCentralAuthAutoLoginWikis
Added rights centralauth-merge, centralauth-unmerge, centralauth-lock. centralauth-oversight, globalgrouppermissions, globalgroupmembership
Hooks used AuthPluginSetup AddNewAccount AbortNewAccount UserLoginComplete UserLoadFromSession UserLogout UserLogoutComplete GetCacheVaryCookies GetPreferences UserArrayFromResult UserGetEmail UserGetEmailAuthenticationTimestamp UserSetEmail UserSetEmailAuthenticationTimestamp UserGetRights UserSetCookies UserLoadDefaults getUserPermissionsErrorsExpensive MakeGlobalVariablesScript SpecialPasswordResetOnSubmit RenameUserWarning RenameUserPreRename RenameUserComplete
Check usage (experimental)

CentralAuth allows global accounts shared between projects. This extension adds seven new special pages — Special:AutoLogin (unlisted special page), Special:CentralAuth, Special:GlobalGroupMembership, Special:GlobalGroupPermissions, Special:WikiSets, Special:GlobalUsers and Special:MergeAccount.

Warning: CentralAuth was designed specifically for Wikimedia projects which already had millions of accounts that needed to be merged into a global table. If you are starting a new wiki farm from scratch and have no need to merge existing accounts into a global table, it is much easier to set up global accounts using $wgSharedDB rather than using CentralAuth. However, this provides no solution to the single-sign-on feature (sign-in on one wiki, like wikipedia.org, automatically makes the user signed-in to e.g. a shared repository under a different, shared domain, like commons.wikimedia.org), nor global account locking.

CentralAuth development is closely tied to the MediaWiki core development trunk. Therefore, if you download the latest CentralAuth version, it may not work with older versions of MediaWiki. In general, for the best results, it may be a good idea to use a trunk version of MediaWiki when using this extension.

Installation

See the setup section below for prerequisites to using CentralAuth. Then follow these instructions when you are ready to activate CentralAuth:

1. Download the latest snapshot and extract it to your extensions directory.
2. Select the database in which to want to CentralAuth's tables to be created (you may wish to create a new database named, for example, CentralAuth) and run central-auth.sql.
3. Add require_once ("$IP/extensions/CentralAuth/CentralAuth.php"); to LocalSettings.php for each of your wikis, or in another PHP file that is included in LocalSettings.php on each of your wikis.
4. The extension should be now active.

Setup

First, you'll need to configure your wiki family using $wgConf, or CentralAuth can't be used for your wiki family. This includes setting $wgLocalDatabases and assigning it to $wgConf->wikis, and $wgConf->settings (minimum is $wgCanonicalServer, $wgServer and $wgArticlePath). Follow the examples carefully. Make sure that you put the configuration code after the require_once ("$IP/extensions/CentralAuth/CentralAuth.php"); line in LocalSettings.php. If you are creating a new wiki family, bear in mind that it may be easier if the databases for the wikis in each group have the same suffix (e.g. hypothetical databases enwiki, dewiki, frwiki, etc., pertaining to wikis belonging to the same group, all have the suffix "wiki").

After installing the extension, you have to gather some data in the CentralAuth database. In order to retroactively set up global accounts, you will have to run the migratePass0.php and migratePass1.php scripts. The first one stores information about your wikis in the CentralAuth database, while the second one uses automatic migration heuristics to generate global accounts. A user can merge their accounts manually via Special:MergeAccount. Dry runs can be used for testing purposes.

To enable global groups, you will have to make an entry into the global_group_permissions table in your CentralAuth database, with gpg_group='steward' and (for access to the group management interface) gpg_permission=globalgrouppermissions. A sample query that is recommended to use is: INSERT INTO global_group_permissions (ggp_group,ggp_permission) VALUES ('steward','globalgrouppermissions'), 'steward','globalgroupmembership');. Then, run migrateStewards.php to promote local stewards to global steward status.

There are various settings you may wish to modify (e.g. whether to provide single sign-on across a whole domain) listed in CentralAuth.php. In particular, you will want to override the default value of $wgCentralAuthDatabase if your CentralAuth database is named something other than 'centralauth'. Make sure you put such settings after the require_once line in LocalSettings.php, e.g.:

require_once ("$IP/extensions/CentralAuth/CentralAuth.php");
$wgCentralAuthDatabase = 'mycentralauthdatabase';

Cache issues

Setting up CentralAuth will require all your wikis to use the same cache server. If they all use memcached it shouldn't be a problem, however if they are configured with the default setting (CACHE_NONE) and use different databases (or prefixes) it won't work (specifically, single logins do not work). Copy the objectcache table's structure to the CentralAuth database. This can be done by using a SQL command such as the following (which assumes your CentralAuth database is named centralauth and that your wiki is named enwiki):

CREATE TABLE centralauth.objectcache LIKE enwiki.objectcache

You also need to configure the following:

$wgSharedDB     = 'centralauth'; // or whatever database you use for central data
$wgSharedTables = array( 'objectcache' ); // remember to copy the table structure's to the central database first
$wgMainCacheType = CACHE_DB; // Tell mediawiki to use objectcache database instead of nothing

Use

Allows for a single-user login (SUL) system using MediaWiki's AuthPlugin system. User creation and login is done globally using one central user table across all wikis. Note that local user accounts are automatically created on account creation/login however.

This extension also implements global user groups, to which global accounts can belong to.

Functions

SUL

A user with an account on more than one wiki may use Special:MergeAccount to create their global user account, which can then be used on any wiki.

Global users

Screenshot of CentralAuth interface on Wikimedia, showing lock/hide interface.

A global account can be locked or hidden by a user with the centralauth-lock and centralauth-oversight permissions, respectively, given to the local group 'stewards' by default. A locked global account will be immediately logged out of any session on any wiki it is currently logged in to, and logins fail with an "incorrect password" error. A hidden global account's username is not visible in any logs except the global account log.

Users with the centralauth-unmerge permission (again, given to stewards by default) can undo a merging of a global account, where the passwords are all reset back to the pre-merge setting.

Warning: Account renames using Extension:Renameuser have to be done locally on every wiki.

Wiki sets

A wiki set is a group of wikis specified by a user with the globalgrouppermissions right. Sets can be opt-in (wikis are not in it by default) or opt-out (wikis are in it unless opted out).

Global user groups

Once you have enabled global user groups as described in the installation section, a migrated steward can use the Special:GlobalGroupPermissions interface to configure global user groups, and their rights. A global user group is active on all wikis (the users in it have its rights on all the wikis) by default, unless the group has been specified to only be active on a specific wiki set (the users in the group only have the rights if they are on a wiki in the set). Global group permissions are not listed at Special:ListUsers, but instead Special:GlobalUsers. They are assigned by a user with the globalgroupmembership permission (by default the global group stewards), and give the specified rights to the user even if the local rights defined by $wgGroupPermissions do not do so.

Licensing and downloads

The extension is available under the GNU General Public License 2.0 or later, and can be downloaded from Git, or accessed via the web-based viewer.

The software is provided as-is. Updates will be made according to the needs of Wikimedia wikis; or where critical vulnerabilities are discovered.

Hooks

This extension adds one new hook:

• CentralAuthWikiList

See also

• m:Single login specifications
• m:Help:Unified login
• $wgSharedDB
• Global session threat assessment
• en:Wikipedia:Integrated watchlists

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