<?php /** * SSL utilities for Requests * * @package Requests * @subpackage Utilities */ /** * SSL utilities for Requests * * Collection of utilities for working with and verifying SSL certificates. * * @package Requests * @subpackage Utilities */ class Requests_SSL { /** * Verify the certificate against common name and subject alternative names * * Unfortunately, PHP doesn't check the certificate against the alternative * names, leading things like 'https://www.github.com/' to be invalid. * Instead * * @see https://tools.ietf.org/html/rfc2818#section-3.1 RFC2818, Section 3.1 * * @throws Requests_Exception On not obtaining a match for the host (`fsockopen.ssl.no_match`) * @param string $host Host name to verify against * @param array $cert Certificate data from openssl_x509_parse() * @return bool */ public static function verify_certificate($host, $cert) { // Calculate the valid wildcard match if the host is not an IP address $parts = explode('.', $host); if (ip2long($host) === false) { $parts[0] = '*'; } $wildcard = implode('.', $parts); $has_dns_alt = false; // Check the subjectAltName if (!empty($cert['extensions']) && !empty($cert['extensions']['subjectAltName'])) { $altnames = explode(',', $cert['extensions']['subjectAltName']); foreach ($altnames as $altname) { $altname = trim($altname); if (strpos($altname, 'DNS:') !== 0) { continue; } $has_dns_alt = true; // Strip the 'DNS:' prefix and trim whitespace $altname = trim(substr($altname, 4)); // Check for a match if (self::match_domain($host, $altname) === true) { return true; } } } // Fall back to checking the common name if we didn't get any dNSName // alt names, as per RFC2818 if (!$has_dns_alt && !empty($cert['subject']['CN'])) { // Check for a match if (self::match_domain($host, $cert['subject']['CN']) === true) { return true; } } return false; } /** * Verify that a reference name is valid * * Verifies a dNSName for HTTPS usage, (almost) as per Firefox's rules: * - Wildcards can only occur in a name with more than 3 components * - Wildcards can only occur as the last character in the first * component * - Wildcards may be preceded by additional characters * * We modify these rules to be a bit stricter and only allow the wildcard * character to be the full first component; that is, with the exclusion of * the third rule. * * @param string $reference Reference dNSName * @return boolean Is the name valid? */ public static function verify_reference_name($reference) { $parts = explode('.', $reference); // Check the first part of the name $first = array_shift($parts); if (strpos($first, '*') !== false) { // Check that the wildcard is the full part if ($first !== '*') { return false; } // Check that we have at least 3 components (including first) if (count($parts) < 2) { return false; } } // Check the remaining parts foreach ($parts as $part) { if (strpos($part, '*') !== false) { return false; } } // Nothing found, verified! return true; } /** * Match a hostname against a dNSName reference * * @param string $host Requested host * @param string $reference dNSName to match against * @return boolean Does the domain match? */ public static function match_domain($host, $reference) { // Check if the reference is blocklisted first if (self::verify_reference_name($reference) !== true) { return false; } // Check for a direct match if ($host === $reference) { return true; } // Calculate the valid wildcard match if the host is not an IP address // Also validates that the host has 3 parts or more, as per Firefox's // ruleset. if (ip2long($host) === false) { $parts = explode('.', $host); $parts[0] = '*'; $wildcard = implode('.', $parts); if ($wildcard === $reference) { return true; } } return false; } }

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