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pantheon-systems / wp-saml-auth

Rock-solid SAML authentication for WordPress built on a modern foundation.
https://wordpress.org/plugins/wp-saml-auth/
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authentication saml wordpress wordpress-plugin

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WP SAML Auth

Contributors: getpantheon, danielbachhuber, outlandish-josh, jazzs3quence
Tags: authentication, SAML
Requires at least: 4.4
Tested up to: 6.3
Requires PHP: 7.3
Stable tag: 2.1.4
License: GPLv2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html

SAML authentication for WordPress.

Description

CircleCI Actively Maintained

SAML authentication for WordPress, using the bundled OneLogin SAML library or optionally installed SimpleSAMLphp. OneLogin provides a SAML authentication bridge; SimpleSAMLphp provides SAML plus a variety of other authentication mechanisms. This plugin acts as a bridge between WordPress and the authentication library.

If your organization uses Google Apps, integrating Google Apps with WP SAML Auth takes just a few steps.

The standard user flow looks like this:

A set of configuration options allow you to change the plugin's default behavior. For instance, permit_wp_login=>false will force all authentication to go through the SAML identity provider, bypassing wp-login.php. Similiarly, auto_provision=>false will disable automatic creation of new WordPress users.

See installation instructions for full configuration details.

Installation

Once you've activated the plugin, and have access to a functioning SAML Identity Provider (IdP), there are a couple of ways WP SAML Auth can be configured:

  1. Settings page in the WordPress backend. The settings page offers the most common configuration options, but not all. It's located at "Settings" -> "WP SAML Auth".
  2. Code snippet applied with a filter. The code snippet approach, documented below, allows access to all configuration settings. The settings page is disabled entirely when a code snippet is present.

If you're connecting directly to an existing IdP, you should use the bundled OneLogin SAML library. The necessary and most common settings are available in the WordPress backend.

If you have more complex authentication needs, then you can also use a SimpleSAMLphp installation running in the same environment. These settings are not configurable through the WordPress backend; they'll need to be defined with a filter. And, if you have a filter in place, the WordPress backend settings will be removed.

Additional explanation of each setting can be found in the code snippet below.

To install SimpleSAMLphp locally for testing purposes, the Identity Provider QuickStart is a good place to start. On Pantheon, the SimpleSAMLphp web directory needs to be symlinked to ~/code/simplesaml to be properly handled by Nginx. Read the docs for more details about configuring SimpleSAMLphp on Pantheon.

Because SAML authentication is handled as a part of the login flow, your SAML identity provider will need to send responses back to wp-login.php. For instance, if your domain is pantheon.io, then you'd use http://pantheon.io/wp-login.php as your AssertionConsumerService configuration value.

To configure the plugin with a filter, or for additional detail on each setting, use this code snippet:

function wpsax_filter_option( $value, $option_name ) {
    $defaults = array(
        /**
         * Type of SAML connection bridge to use.
         *
         * 'internal' uses OneLogin bundled library; 'simplesamlphp' uses SimpleSAMLphp.
         *
         * Defaults to SimpleSAMLphp for backwards compatibility.
         *
         * @param string
         */
        'connection_type' => 'internal',
        /**
         * Configuration options for OneLogin library use.
         *
         * See comments with "Required:" for values you absolutely need to configure.
         *
         * @param array
         */
        'internal_config'        => array(
            // Validation of SAML responses is required.
            'strict'       => true,
            'debug'        => defined( 'WP_DEBUG' ) && WP_DEBUG ? true : false,
            'baseurl'      => home_url(),
            'sp'           => array(
                'entityId' => 'urn:' . parse_url( home_url(), PHP_URL_HOST ),
                'assertionConsumerService' => array(
                    'url'  => wp_login_url(),
                    'binding' => 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST',
                ),
            ),
            'idp'          => array(
                // Required: Set based on provider's supplied value.
                'entityId' => '',
                'singleSignOnService' => array(
                    // Required: Set based on provider's supplied value.
                    'url'  => '',
                    'binding' => 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect',
                ),
                'singleLogoutService' => array(
                    // Required: Set based on provider's supplied value.
                    'url'  => '',
                    'binding' => 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect',
                ),
                // Required: Contents of the IDP's public x509 certificate.
                // Use file_get_contents() to load certificate contents into scope.
                'x509cert' => '',
                // Optional: Instead of using the x509 cert, you can specify the fingerprint and algorithm.
                'certFingerprint' => '',
                'certFingerprintAlgorithm' => '',
            ),
        ),
        /**
         * Path to SimpleSAMLphp autoloader.
         *
         * Follow the standard implementation by installing SimpleSAMLphp
         * alongside the plugin, and provide the path to its autoloader.
         * Alternatively, this plugin will work if it can find the
         * `SimpleSAML_Auth_Simple` class.
         *
         * @param string
         */
        'simplesamlphp_autoload' => dirname( __FILE__ ) . '/simplesamlphp/lib/_autoload.php',
        /**
         * Authentication source to pass to SimpleSAMLphp
         *
         * This must be one of your configured identity providers in
         * SimpleSAMLphp. If the identity provider isn't configured
         * properly, the plugin will not work properly.
         *
         * @param string
         */
        'auth_source'            => 'default-sp',
        /**
         * Whether or not to automatically provision new WordPress users.
         *
         * When WordPress is presented with a SAML user without a
         * corresponding WordPress account, it can either create a new user
         * or display an error that the user needs to contact the site
         * administrator.
         *
         * @param bool
         */
        'auto_provision'         => true,
        /**
         * Whether or not to permit logging in with username and password.
         *
         * If this feature is disabled, all authentication requests will be
         * channeled through SimpleSAMLphp.
         *
         * @param bool
         */
        'permit_wp_login'        => true,
        /**
         * Attribute by which to get a WordPress user for a SAML user.
         *
         * @param string Supported options are 'email' and 'login'.
         */
        'get_user_by'            => 'email',
        /**
         * SAML attribute which includes the user_login value for a user.
         *
         * @param string
         */
        'user_login_attribute'   => 'uid',
        /**
         * SAML attribute which includes the user_email value for a user.
         *
         * @param string
         */
        'user_email_attribute'   => 'mail',
        /**
         * SAML attribute which includes the display_name value for a user.
         *
         * @param string
         */
        'display_name_attribute' => 'display_name',
        /**
         * SAML attribute which includes the first_name value for a user.
         *
         * @param string
         */
        'first_name_attribute' => 'first_name',
        /**
         * SAML attribute which includes the last_name value for a user.
         *
         * @param string
         */
        'last_name_attribute' => 'last_name',
        /**
         * Default WordPress role to grant when provisioning new users.
         *
         * @param string
         */
        'default_role'           => get_option( 'default_role' ),
    );
    $value = isset( $defaults[ $option_name ] ) ? $defaults[ $option_name ] : $value;
    return $value;
}
add_filter( 'wp_saml_auth_option', 'wpsax_filter_option', 10, 2 );

If you need to adapt authentication behavior based on the SAML response, you can do so with the wp_saml_auth_pre_authentication filter:

/**
 * Reject authentication if $attributes doesn't include the authorized group.
 */
add_filter( 'wp_saml_auth_pre_authentication', function( $ret, $attributes ) {
    if ( empty( $attributes['group'] ) || ! in_array( 'administrators', $attributes['group'] ) ) {
        return new WP_Error( 'unauthorized-group', "Sorry, you're not a member of an authorized group." );
    }
    return $ret;
}, 10, 2 );

WP-CLI Commands

This plugin implements a variety of WP-CLI commands. All commands are grouped into the wp saml-auth namespace.

$ wp help saml-auth

NAME

  wp saml-auth

DESCRIPTION

  Configure and manage the WP SAML Auth plugin.

SYNOPSIS

  wp saml-auth <command>

SUBCOMMANDS

  scaffold-config      Scaffold a configuration filter to customize WP SAML Auth usage.

Use wp help saml-auth <command> to learn more about each command.

Contributing

See CONTRIBUTING.md for information on contributing.

Security Policy

Reporting Security Bugs

Please report security bugs found in the WP SAML Auth plugin's source code through the Patchstack Vulnerability Disclosure Program. The Patchstack team will assist you with verification, CVE assignment, and notify the developers of this plugin.

Frequently Asked Questions

Can I update an existing WordPress user's data when they log back in?

If you'd like to make sure the user's display name, first name, and last name are updated in WordPress when they log back in, you can use the following code snippet:

/**
 * Update user attributes after a user has logged in via SAML.
 */
add_action( 'wp_saml_auth_existing_user_authenticated', function( $existing_user, $attributes ) {
    $user_args = array(
        'ID' => $existing_user->ID,
    );
    foreach ( array( 'display_name', 'first_name', 'last_name' ) as $type ) {
        $attribute          = \WP_SAML_Auth::get_option( "{$type}_attribute" );
        $user_args[ $type ] = ! empty( $attributes[ $attribute ][0] ) ? $attributes[ $attribute ][0] : '';
    }
    wp_update_user( $user_args );
}, 10, 2 );

The wp_saml_auth_existing_user_authenticated action fires after the user has successfully authenticated with the SAML IdP. The code snippet then uses a pattern similar to WP SAML Auth to fetch display name, first name, and last name from the SAML response. Lastly, the code snippet updates the existing WordPress user object.

How do I use SimpleSAMLphp and WP SAML Auth on a multi web node environment?

Because SimpleSAMLphp uses PHP sessions to manage user authentication, it will work unreliably or not at all on a server configuration with multiple web nodes. This is because PHP's default session handler uses the filesystem, and each web node has a different filesystem. Fortunately, there's a way around this.

First, install and activate the WP Native PHP Sessions plugin, which registers a database-based PHP session handler for WordPress to use.

Next, modify SimpleSAMLphp's www/_include.php file to require wp-load.php. If you installed SimpleSAMLphp within the wp-saml-auth directory, you'd edit wp-saml-auth/simplesamlphp/www/_include.php to include:

<?php
require_once dirname( dirname( dirname( dirname( dirname( dirname( __FILE__ ) ) ) ) ) ) . '/wp-load.php';

Note: the declaration does need to be at the top of _include.php, to ensure WordPress (and thus the session handling) is loaded before SimpleSAMLphp.

There is no third step. Because SimpleSAMLphp loads WordPress, which has WP Native PHP Sessions active, SimpleSAMLphp and WP SAML Auth will be able to communicate to one another on a multi web node environment.

Upgrade Notice

2.0.0

Minimum supported PHP version is 7.3.

Changelog

2.1.4 (November 27, 2023)

2.1.3 (April 8, 2023)

2.1.2 (April 7, 2023)

2.1.1 (March 15, 2023)

2.1.0 (November 29, 2022)

2.0.1 (January 24, 2022)

2.0.0 (January 6, 2022)

1.2.7 (December 9, 2021)

1.2.6 (October 12, 2021)

1.2.5 (August 18, 2021)

1.2.4 (August 18, 2021)

1.2.3 (May 25, 2021)

1.2.2 (Apr 26, 2021)

1.2.1 (Mar 2, 2021)

1.2.0 (Feb 22, 2021)

1.1.1 (Feb 3, 2021)

1.1.0 (Dec 1, 2020)

1.0.2 (May 27, 2020)

1.0.1 (May 26, 2020)

1.0.0 (March 2, 2020)

0.8.3 (February 3, 2020)

0.8.2 (January 22, 2020)

0.8.1 (November 25, 2019)

0.8.0 (November 20, 2019)

0.7.3 (November 7, 2019)

0.7.2 (October 30, 2019)

0.7.1 (September 26, 2019)

0.7.0 (September 16, 2019)

0.6.0 (May 14, 2019)

0.5.2 (April 8, 2019)

0.5.1 (November 15, 2018)

0.5.0 (November 7, 2018)

0.4.0 (September 5, 2018)

0.3.11 (July 18, 2018)

0.3.10 (June 28, 2018)

0.3.9 (March 29, 2018)

0.3.8 (February 26, 2018)

0.3.7 (February 13, 2018)

0.3.6 (February 7, 2018)

0.3.5 (January 19, 2018)

0.3.4 (December 22, 2017)

0.3.3 (November 28, 2017)

0.3.2 (November 9, 2017)

0.3.1 (July 12, 2017)

0.3.0 (June 29, 2017)

0.2.2 (May 24, 2017)

0.2.1 (March 22, 2017)

0.2.0 (March 7, 2017)

0.1.0 (April 18, 2016)