Always add the CN as the first SAN when creating a certificate in the…

… GUI or an automatic GUI self-signed certificate. Per RFC 2818, relying on the CN to determine the hostname is deprecated, SANs are required. Chrome 58 started enforcing this requirement. Fixes #7496

src/etc/inc/system.inc

@@ -1281,14 +1281,16 @@ function system_webgui_create_certificate() {
 	$cert = array();
 	$cert['refid'] = uniqid();
 	$cert['descr'] = sprintf(gettext("webConfigurator default (%s)"), $cert['refid']);
+	$cert_hostname = "{$config['system']['hostname']}-{$cert['refid']}";
 
 	$dn = array(
 		'countryName' => "US",
 		'stateOrProvinceName' => "State",
 		'localityName' => "Locality",
 		'organizationName' => "{$g['product_name']} webConfigurator Self-Signed Certificate",
 		'emailAddress' => "admin@{$config['system']['hostname']}.{$config['system']['domain']}",
-		'commonName' => "{$config['system']['hostname']}-{$cert['refid']}");
+		'commonName' => $cert_hostname,
+		'subjectAltName' => "DNS:{$cert_hostname}");
 	$old_err_level = error_reporting(0); /* otherwise openssl_ functions throw warnings directly to a page screwing menu tab */
 	if (!cert_create($cert, null, 2048, 2000, $dn, "self-signed", "sha256")) {
 		while ($ssl_err = openssl_error_string()) {

src/usr/local/www/system_certmanager.php

@@ -426,12 +426,20 @@
 					if (!empty($pconfig['dn_organizationalunit'])) {
 						$dn['organizationalUnitName'] = $pconfig['dn_organizationalunit'];
 					}
+					if (is_ipaddr($pconfig['dn_commonname'])) {
+						$altnames_tmp = array("IP:{$pconfig['dn_commonname']}");
+					} else {
+						$altnames_tmp = array("DNS:{$pconfig['dn_commonname']}");
+					}
 					if (count($altnames)) {
-						$altnames_tmp = "";
 						foreach ($altnames as $altname) {
-							$altnames_tmp[] = "{$altname['type']}:{$altname['value']}";
+							// The CN is added as a SAN automatically, do not add it again.
+							if ($altname['value'] != $pconfig['dn_commonname']) {
+								$altnames_tmp[] = "{$altname['type']}:{$altname['value']}";
+							}
 						}
-
+					}
+					if (!empty($altnames_tmp)) {
 						$dn['subjectAltName'] = implode(",", $altnames_tmp);
 					}
 
@@ -797,6 +805,8 @@
 
 		$group->addClass('repeatable');
 
+		$group->setHelp('Enter additional identifiers for the certificate in this list. The Common Name field is automatically added to the certificate as an Alternative Name.');
+
 		$section->add($group);
 
 		$counter++;