README

A SilverStripe module that lets you log into a SilverStripe site from a centralized system using signed JWTs and then redirects you into the CMS.

In short: the module validates a signed JSON Web Token (JWT) passed via the URL. On successful validation a configured user (or the default admin) is automatically logged in and redirected to a configured destination URL.

Use the Silverstripe Gate Manager on your admin instance to do so.

Installation

This package is intended to be installed via Composer. From your project root:

composer require atwx/silverstripe-gate-client

Configuration

Configure the module via SilverStripe YAML config. Important options:

Atwx\SilverGateClient\Services\TokenService:
  public_key: |
    -----BEGIN PUBLIC KEY-----
    ...
    -----END PUBLIC KEY-----

# Login as admin is default
Atwx\SilverGateClient\Services\LoginService:
  # Finds the current default admin or creates one if none exists
  login_as_default_admin: true
  #member_id: 1
  #member_email: xyz@example.com

Note: the key must be in PEM format. Tokens should be signed by the central system that issues them with the corresponding private key (for example RS256).

You can also use the .env to configure the public key. Make sure to escape newlines using \n:

SILVERGATECLIENT_PUBLIC_KEY="-----BEGIN PUBLIC KEY-----\n...\n-----END PUBLIC KEY-----"

More advanced configuration:

Atwx\SilverGateClient\Services\TokenService:
  public_key: |
    -----BEGIN PUBLIC KEY-----
    ...
    -----END PUBLIC KEY-----
  # defaults to 60, specifies how old the token is allowed to be before it is invalidated
  token_max_age_seconds: 60

Atwx\SilverGateClient\Services\LoginService:
  member_id: 1
  login_dest: '/custom-url-after-login'

Sudo Mode

By default, SilverStripe's Sudo Mode is not activated after a JWT login. This means users who access sudo-protected CMS areas (e.g. certain security settings) will be prompted for their password — which is not possible for SSO users.

You can opt in to automatically bypassing sudo mode for JWT-authenticated sessions:

Via .env:

SILVERGATECLIENT_DISABLE_SUDO_MODE=1

Via YAML:

Atwx\SilverGateClient\Services\LoginService:
  disable_sudo_mode: true

When enabled, a jwt-authenticated flag is set in the session after a successful JWT login. A SudoModeExtension on SudoModeService detects this flag and marks sudo mode as active for the duration of the session.

Security considerations:

• The feature is opt-in and disabled by default.
• The session flag is only set after JWT signature validation and a successful member login.
• The flag is cleared when the user logs out (session is destroyed).
• Unlike normal sudo mode (which times out after 45 minutes), the bypass is active for the entire session. This is intentional for SSO users who cannot enter a password.

Route / Endpoint

The module registers the route /_silvergateclient (see _config/routes.yml).

Primary endpoint:

• GET /_silvergateclient/token/<urlencoded_base64_jwt>

Example (as used in the tests):

$token = JWT::encode(['iat' => time()], $privateKey, 'RS256');
$b64 = urlencode(base64_encode($token));
// GET /_silvergateclient/token/<$b64>