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hamrokhaanpaan/wp-includes/Requests/SSL.php

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+<?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.
+	 *
+	 * @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) {
+		$has_dns_alt = false;
+
+		// Check the subjectAltName
+		if (!empty($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;
+	}
+}