MediaWiki

Extension:JWTAuth

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この拡張機能では、先に PluggableAuth 拡張機能をインストールする必要があります。
MediaWiki 拡張機能マニュアル
JWTAuth
リリースの状態: 安定
実装 利用者識別 , 利用者権限
説明 Adds support for using JSON Web Tokens to log in to MediaWiki
作者 Jeffrey Wang (MyWikis-JeffreyWangトーク)
最新バージョン 2.0.0
互換性の方針 後方互換性を維持するメイン ブランチ。
MediaWiki 1.35.0+
データベースの変更 はい
ライセンス MIT ライセンス
ダウンロード
拡張機能をダウンロード
Git [?]:
パラメーター
$wgJWTAuthAlgorithm, $wgJWTAuthKey, $wgJWTGroupMapping, $wgJWTAuthDebugMode
使用するフック
四半期ごとのダウンロード数 3 (Ranked 137th)
translatewiki.net で翻訳を利用できる場合は、JWTAuth 拡張機能の翻訳にご協力ください

The JWTAuth extension adds support for using JSON Web Tokens to log in to MediaWiki. JWTs are a common medium for conveying an authentication assertion in the tangible form of a token.

JWTAuth 2.0.0 was released on July 24, 2023. The extension was rewritten to use PluggableAuth.

JWTAuth 2.0.0 is not currently well documented, and as a result, it may be very difficult to use. Some users have reported better success with using the 1.x version (pre-PluggableAuth) for the time being.

Version 1 vs. version 2

Some users have reported version 2 is difficult to use due to the documentation being sparse. While the developers work on this, you can use version 1, which has been reported to still work very well.

Prerequisites

JWTAuth is not a complete auth system. It is simply the last mile of processing JWTs. To learn more about how JWTs work, go to JWT.io. JWTAuth only facilitates the verification of JWTs that were already issued. Therefore, an auth system that issues JWTs is the primary prerequisite.

As of JWTAuth 2.0.0, the extension is based off of PluggableAuth and requires PluggableAuth 7.0 or higher to be installed on the wiki.

The JWT needs to be passed into the wiki's Special:JWTLogin page. It will take whatever content is POSTed in the Authorization parameter (query string) and process it. The content should begin with Bearer  (with a space after the word "Bearer") or Bearer:, followed by the actual JWT.

Why use JWTAuth?

 
Presentation about JWTAuth at EMWCon Spring 2023 (before it was rewritten to use PluggableAuth)

JSON Web Tokens are a widely used medium to encode session data. They are issued by an identity provider (IdP) and consumed by service providers (SPs) by using a mutually agreed upon key (whether symmetric or asymmetric) to check if a given token is valid or not. If the SP is presented with a supposedly valid token supposedly issued by the IdP, it is taken for face value and the user is authenticated into the service.

Advantages

JWTs are useful for persisting auth session throughout the token's life because it means it can reuse token across multiple services and avoids needing to log in multiple times. It's best for systems where user will be logged in to several sites at once, including MediaWiki, and when sites are accessed from a central login system.

The JWTAuth extension doesn't require a JWT to be sent with each request to the web server. It only needs it to be sent once to Special:JWTLogin per login session. Once the JWTAuth extension authenticates the user based on the validity of the token, a cookie is set in MediaWiki to authenticate them for the rest of the MediaWiki session. The rest of the session is managed by MediaWiki and JWTAuth doesn't interface with it after that point.

Limitations

One inherent limitation of JWTAuth is its inability to check for whether tokens are revoked. This is not a bug; it is expected behavior because of the design of this auth process. It is able to detect whether the token is expired or forged, but if a token were to be revoked before the scheduled expiry time, the JWTAuth extension would have no way of knowing, as it doesn't talk back with the IdP who issued the token. Most PluggableAuth-based extensions don't suffer from this limitation. Usually, it's best to use the JWTAuth extension in an environment where the ability to immediate revoke a token is either unnecessary because another layer of auth would take care of it (like a company-issued computer shutting down when its associated employee's employment comes to an end), or not important. The best way to mitigate this issue would be to set the validity period to be as short as possible.

This also means JWTAuth doesn't include single sign-out.

There are many discussions of the merits of using JWTs versus other authentication mechanisms, and especially about what the best way to use them would be, but they are beyond the scope of this page. Please see JWT.io to learn more about JWTs.

Installation

  • ダウンロードして、ファイルをextensions/フォルダー内のJWTAuthという名前のディレクトリ内に配置します。
    開発者とコード寄稿者は、上記の代わりに以下を使用してGitからインストールします:cd extensions/
    git clone https://gerrit.wikimedia.org/r/mediawiki/extensions/JWTAuth
  • 以下のコードを LocalSettings.php ファイルの末尾に追加します: 
    wfLoadExtension( 'JWTAuth' );
$wgJWTAuth_Algorithm = ''; // can be: HS256, RS256, EdDSA
$wgJWTAuth_Key = ''; // Depends on which algorithm you are using
  •   完了 – ウィキの「Special:Version」に移動して、拡張機能が正しくインストールされたことを確認します。

Configuration

This section is out of date - we are working on fixing this.

As of August 10, 2024, JWTAuth 2.0 doesn't use the $wgPluggableAuth_Config[]['data'] array to configure it. Instead, the extension still uses its own config variable naming format, which is explained below. (This is a legacy carried over from the original v1 implementation.)

$wgJWTAuth_Algorithm
The algorithm used to encode and decode the JWT. Currently, only HS256, RS256, and EdDSA are supported. The former uses a simple passphrase, whereas the latter two use a public/private keypair. As elliptical curves cannot be cracked by quantum algorithms, we highly recommend EdDSA.
$wgJWTAuth_Key
When using a symmetric encryption algorithm like HS256, this is the shared passkey used to encode and decode the JWT.
When using an asymmetric encryption algorithm such as RS256 or EdDSA, this is the public key. (The private key would be stored on side of the issuer of the JWT.)

Integrating your auth system with JWTAuth on MediaWiki

The following procedure must be followed to successfully authenticate a user into the wiki:

  1. A JWT claim must be well formed and encoded into the JWT payload format using the key that has already been agreed upon.
  2. Find the path to your wiki's location of Special:JWTLogin. For instance, if your wiki is under https://wiki.example.com and $wgArticlePath = "/wiki/$1"; then the location is https://wiki.example.com/wiki/Special:JWTLogin.
  3. The payload must be POSTed to this aforementioned URL. The URL should have a parameter called Authorization with the content Bearer: JWTTOKENHERE. For instance, Bearer: eyJhbGciOiJIUzI...66Vkfljr.
  4. The payload must conform to the claim names promulgated by IANA: https://www.iana.org/assignments/jwt/jwt.xhtml

Below are the claims that are required by the JWTAuth extension. If any of these are missing, the authentication process will fail. If you are unsure of what these mean, or the allowed values for them, please visit https://jwt.io for more details.

  • preferred_username: Username. This is used by JWTAuth to form the user's username on MediaWiki. Please make sure the usernames conform to MediaWiki's allowed username rules.
  • exp: Expiry timestamp.
  • iat: Issued at timestamp.
  • nbf: Not valid before timestamp.
  • iss: Issuer
  • aud: Audience
  • sub: Subject

You can put nonsense (but nonempty) values for iss, aud, and sub, as they are not checked by JWTAuth, but our JWT decoding library (Firebase JWT) will cause the auth process to fail if they are not set.

The following claims are optional, but are highly recommended because they will be added to users' profiles:

  • email
  • family_name
  • given_name

As of 0.1.0, most of these claim names cannot be changed to match the token generator's preferences because these claim names are standard conventions. The party generating the token is responsible for sending well-formed responses that conform to internet standards. As of JWTAuth 2.0.0, the groups claim name cannot be changed anymore.

If you want to assign groups to a user, pass them in, separated by commas, by using the groups claim. The groups will be synced using the group sync mechanism present in PluggableAuth. To configure it, see Extension:PluggableAuth#Group_Synchronization.

Please see the README for this extension for more details.

See also

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