vip-proxy-verification-info.php

<?php
/*
Plugin Name: WordPress VIP Proxy Verification
Description: Adds a new section to the WordPress Site Health Info page in wp-admin for helping to configure WordPress VIP Proxy Verification.
Version: 1.0.0
Author: Rick Hurst
*/

namespace VIPSiteInfo\ReverseProxy;

function vip_prepare_site_health($tab) {
    if ('debug' === $tab && current_user_can('manage_options')) {
        add_filter('debug_information', '\VIPSiteInfo\ReverseProxy\vip_proxy_verification_section');
    }
}

// Obfuscate the string by replacing characters with asterisks (*)
function obfuscate_string($string) {
    $length = strlen($string);
    if ($length <= 3) {
        return $string;
    }

    $obfuscated = str_repeat('*', $length - 3) . substr($string, -3);
    return $obfuscated;
}

// Add the VIP Proxy Verification section to the Site Health Info page
function vip_proxy_verification_section($info) {

    // VIP proxy verification header as configured for this application at VIP
    $vip_proxy_verification = defined('WPCOM_VIP_PROXY_VERIFICATION') ? WPCOM_VIP_PROXY_VERIFICATION : '';
    
    // Proxy verification request header sent as a custom header by the Remote Proxy
    $remote_proxy_verification = isset($_SERVER['HTTP_X_VIP_PROXY_VERIFICATION']) ? $_SERVER['HTTP_X_VIP_PROXY_VERIFICATION'] : '';
    
    // The remote user IP address as provided by Akamai and others
    $true_client_ip = isset($_SERVER['HTTP_TRUE_CLIENT_IP']) ? $_SERVER['HTTP_TRUE_CLIENT_IP'] : '';

    // Cloudflare connecting IP (https://support.cloudflare.com/hc/en-us/articles/200170986)
    $cf_connecting_ip = isset($_SERVER['HTTP_CF_CONNECTING_IP']) ? $_SERVER['HTTP_CF_CONNECTING_IP'] : '';

    // Proxy verifications strings should match
    $verification_status = ($vip_proxy_verification !== '' && $remote_proxy_verification !== '' && $vip_proxy_verification === $remote_proxy_verification) ? 'correct' : 'incorrect';

    // If the VIP proxy header verification code has been applied correctly, the remote address
    // will mirror the user's remote IP https://docs.wpvip.com/how-tos/configure-a-reverse-proxy/#h-the-x-vip-proxy-verification-method-recommended
    $remote_ip = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : '';

    // Other IP address headers which might be useful for debugging
    $ip_forwarded_for = isset($_SERVER['HTTP_X_FORWARDED_FOR']) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : '';
    $ip_trail = isset($_SERVER['HTTP_X_IP_TRAIL']) ? $_SERVER['HTTP_X_IP_TRAIL'] : '';

    // Array needed to display on the Site Info page
    $info['vip-proxy-verification'] = [
        'label' => 'VIP Proxy Verification',
        'fields' => [
            'proxy-verification-vip' => [
                'label' => 'Proxy Verification Secret (VIP)',
                'value' => ($vip_proxy_verification !== '') ? obfuscate_string($vip_proxy_verification) : "(not found)",
            ],
            'proxy-verification-remote' => [
                'label' => 'Proxy Verification Secret (Reverse Proxy)',
                'value' => ($remote_proxy_verification !== '') ? obfuscate_string($remote_proxy_verification) : "(not found)"
            ],
            'proxy-verification-status' => [
                'label' => 'Proxy Header Verification Status',
                'value' => $verification_status,
            ],
            'true-client-ip' => [
                'label' => 'True Client IP (sent by Akamai and others)',
                'value' => ($true_client_ip !== '') ? $true_client_ip : "(not found)"
            ],
            'cf-connecting-ip' => [
                'label' => 'Cloudflare connecting IP',
                'value' => ($cf_connecting_ip !== '') ? $cf_connecting_ip : "(not found)"
            ],
            'remote-ip' => [
                'label' => 'Remote IP',
                'value' => ($remote_ip !== '') ? $remote_ip : "(not found)"
            ],
            'ip-forwarded-for' => [
                'label' => 'IP Forwarded For',
                'value' => ($ip_forwarded_for !== '') ? $ip_forwarded_for : "(not found)"
            ],
            'ip-trail' => [
                'label' => 'IP Trail',
                'value' => ($ip_trail !== '') ? $ip_trail : "(not found)"
            ],
        ],
    ];

    return $info;
}
add_action('site_health_tab_content', '\VIPSiteInfo\ReverseProxy\vip_prepare_site_health');