From 3c11bd3c5b42e54f341b05f07bf27bc8131d80d3 Mon Sep 17 00:00:00 2001
From: Matthew Grooms <mgrooms@pfsense.org>
Date: Sat, 6 Sep 2008 21:10:43 +0000
Subject: Minor re-work of OpenVPN configuration. Use operational modes to
 determine what configuration options are appropriate. The operational mode
 dictates the authentication method. They are defines as follows ...

Peer to Peer ( SSL/TLS )
Peer to Peer ( Shared Key )
Remote Access ( SSL/TLS )
Remote Access ( User Auth )
Remote Access ( SSL/TLS + User Auth )

Some of these modes allow for user authentication using passwords. We now
use the etc/inc/openvpn.auth-user.php file to facilitate this by checking
the username and password supplied by OpenVPN against our centralized user
database.

The Server and Client user interfaces have also been updated to support
TLS packet authentication. This is an additional security option that is
optional.
---
 etc/inc/config.inc            |  17 ++++
 etc/inc/openvpn.auth-user.php |  79 +++++++++++++++
 etc/inc/openvpn.inc           | 219 ++++++++++++++++++++++++++----------------
 3 files changed, 231 insertions(+), 84 deletions(-)
 create mode 100755 etc/inc/openvpn.auth-user.php

(limited to 'etc')

diff --git a/etc/inc/config.inc b/etc/inc/config.inc
index 5a52611..0cd4476 100644
--- a/etc/inc/config.inc
+++ b/etc/inc/config.inc
@@ -1747,6 +1747,16 @@ endif;
 					$index++;
 				}
 
+				/* determine operational mode */
+				if ($server['auth_method'] == 'pki') {
+					if($server['nopool'])
+						$server['mode'] = "p2p_tls";
+					else
+						$server['mode'] = "server_tls";
+				} else
+					$server['mode'] = "p2p_shared_key";
+				unset($server['auth_method']);
+
 				/* modify configuration values */
 				unset($server['dh_params']);
 				if (!$server['interface'])
@@ -1829,6 +1839,13 @@ endif;
 					$index++;
 				}
 
+				/* determine operational mode */
+				if ($client['auth_method'] == 'pki')
+					$client['mode'] = "p2p_tls";
+				else
+					$client['mode'] = "p2p_shared_key";
+				unset($client['auth_method']);
+
 				/* modify configuration values */
 				if (!$client['interface'])
 					$client['interface'] = 'wan';
diff --git a/etc/inc/openvpn.auth-user.php b/etc/inc/openvpn.auth-user.php
new file mode 100755
index 0000000..275f54d
--- /dev/null
+++ b/etc/inc/openvpn.auth-user.php
@@ -0,0 +1,79 @@
+#!/usr/local/bin/php -f
+<?php
+/* $Id$ */
+/*
+    openvpn.auth-user.php
+
+    Copyright (C) 2008 Shrew Soft Inc
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are met:
+
+    1. Redistributions of source code must retain the above copyright notice,
+       this list of conditions and the following disclaimer.
+
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+    AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+    AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+    POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/*
+ * OpenVPN calls this script to authenticate a user
+ * based on a username and password. We lookup these
+ * in our config.xml file and check the credentials.
+ */
+
+require_once("config.inc");
+
+function & lookup_user($name) {
+	global $config;
+
+	foreach($config['system']['user'] as & $userent)
+		if ($userent['name'] == $name)
+			return $userent;
+}
+
+/* setup syslog logging */
+openlog("openvpn", LOG_ODELAY, LOG_AUTH);
+
+/* read data from environment */
+$username = getenv("username");
+$password = getenv("password");
+
+if (!$username || !$password) {
+	syslog(LOG_ERROR, "invalid user authentication environment");
+	exit(-1);
+}
+
+/* lookup user object by name */
+$user =& lookup_user($username);
+
+if (!$user) {
+	syslog(LOG_WARNING, "user {$username} is unknown");
+	exit(-2);
+}
+
+/* authenticate the user */
+$password = crypt($password, $user['password']);
+
+if ($password != $user['password']) {
+	syslog(LOG_WARNING, "user {$username} supplied an invalid password\n");
+	exit(-3);
+}
+
+syslog(LOG_WARNING, "user {$username} authenticated\n");
+exit(0);
+
+?>
diff --git a/etc/inc/openvpn.inc b/etc/inc/openvpn.inc
index 8dda12e..abc2337 100644
--- a/etc/inc/openvpn.inc
+++ b/etc/inc/openvpn.inc
@@ -49,13 +49,45 @@ require_once('util.inc');
 
 $openvpn_prots = array("UDP", "TCP");
 
-$openvpn_auth_methods = array(
-	'pki' => "Public Key Infrastructure",
-	'shared_key' => "Pre Shared Key");
+/* 
+ * The User Auth mode below is disabled because
+ * OpenVPN erroneously requires that we provide
+ * a CA configuration parameter. In this mode,
+ * clients don't send a certificate so there is
+ * no need for a CA. If we require that admins
+ * provide one in the pfSense UI due to a bogus
+ * requirement imposed by OpenVPN, it could be
+ * considered very confusing ( I know I was ).
+ *
+ * -mgrooms
+ */
+
+$openvpn_server_modes = array(
+	'p2p_tls' => "Peer to Peer ( SSL/TLS )",
+	'p2p_shared_key' => "Peer to Peer ( Shared Key )",
+	'server_tls' => "Remote Access ( SSL/TLS )",
+//	'server_user' => "Remote Access ( User Auth )",
+	'server_tls_user' => "Remote Access ( SSL/TLS + User Auth )");
+
+$openvpn_client_modes = array(
+	'p2p_tls' => "Peer to Peer ( SSL/TLS )",
+	'p2p_shared_key' => "Peer to Peer ( Shared Key )" );
+
+function openvpn_create_key() {
+
+	$fp = popen("/usr/local/sbin/openvpn --genkey --secret /dev/stdout 2>/dev/null", "r");
+	if (!$fp)
+		return false;
+
+	$rslt = stream_get_contents($fp);
+	pclose($fp);
+
+	return $rslt;
+}
 
 function openvpn_create_dhparams($bits) {
 
-	$fp = popen("/usr/bin/openssl dhparam {$bits}", "r");
+	$fp = popen("/usr/bin/openssl dhparam {$bits} 2>/dev/null", "r");
 	if (!$fp)
 		return false;
 
@@ -268,61 +300,64 @@ function openvpn_reconfigure($mode,& $settings) {
 	$lines = explode(' ', trim(shell_exec("ifconfig {$iface} | grep inet | grep -v inet6")));
 	$iface_ip = $lines[1];
 
-$conf .= <<<EOD
-dev {$devname}
-dev-type tun
-dev-node /dev/{$tunname}
-writepid {$pfile}
-#user nobody
-#group nobody
-daemon
-keepalive 10 60
-ping-timer-rem
-persist-tun
-persist-key
-proto $proto
-cipher $cipher
-up /etc/rc.filter_configure
-down /etc/rc.filter_configure
-local {$iface_ip}
-
-EOD;
-
-	// Mode specific stuff
+	$conf  = "dev {$devname}\n";
+	$conf .= "dev-type tun\n";
+	$conf .= "dev-node /dev/{$tunname}\n";
+	$conf .= "writepid {$pfile}\n";
+	$conf .= "#user nobody\n";
+	$conf .= "#group nobody\n";
+	$conf .= "daemon\n";
+	$conf .= "keepalive 10 60\n";
+	$conf .= "ping-timer-rem\n";
+	$conf .= "persist-tun\n";
+	$conf .= "persist-key\n";
+	$conf .= "proto {$proto}\n";
+	$conf .= "cipher {$cipher}\n";
+	$conf .= "up /etc/rc.filter_configure\n";
+	$conf .= "down /etc/rc.filter_configure\n";
+	$conf .= "local {$iface_ip}\n";
+
+	// server specific settings
 
 	if ($mode == 'server') {
 
 		list($ip, $mask) = explode('/', $settings['tunnel_network']);
 		$mask = gen_subnet_mask($mask);
 
-		// Using a shared key or not dynamically assigning IPs to the clients
-		if (($settings['auth_method'] == 'shared_key') || (!$settings['pool_enable'] == 'on')) {
-
-			if ($settings['auth_method'] == 'pki')
+		// configure tls modes
+		switch($settings['mode']) {
+			case 'p2p_tls':
+			case 'server_tls':
+			case 'server_tls_user':
 				$conf .= "tls-server\n";
-
-			$baselong = ip2long($ip) & ip2long($mask);
-			$ip1 = long2ip($baselong + 1);
-			$ip2 = long2ip($baselong + 2);
-			$conf .= "ifconfig $ip1 $ip2\n";
+				break;
 		}
-		// Using a PKI
-		else if ($settings['auth_method'] == 'pki') {
 
-			if ($settings['client2client'])
-				$conf .= "client-to-client\n";
-
-			$conf .= "server $ip $mask\n";
-			$csc_dir = "{$g['varetc_path']}/openvpn-csc";
-			$conf .= "client-config-dir $csc_dir\n";
+		// configure p2p/server modes
+		switch($settings['mode']) {
+			case 'p2p_tls':
+			case 'p2p_shared_key':
+				$baselong = ip2long($ip) & ip2long($mask);
+				$ip1 = long2ip($baselong + 1);
+				$ip2 = long2ip($baselong + 2);
+				$conf .= "ifconfig $ip1 $ip2\n";
+				break;
+			case 'server_tls':
+			case 'server_user':
+			case 'server_tls_user':
+				$conf .= "server {$ip} {$mask}\n";
+				$conf .= "client-config-dir {$g['varetc_path']}/openvpn-csc\n";
+				break;
 		}
 
-		// We can push routes
-		if (!empty($settings['local_network'])) {
-
-			list($ip, $mask) = explode('/', $settings['local_network']);
-			$mask = gen_subnet_mask($mask);
-			$conf .= "push \"route $ip $mask\"\n";
+		// configure user auth modes
+		switch($settings['mode']) {
+			case 'server_user':
+				$conf .= "client-cert-not-required\n";
+			case 'server_tls_user':
+				$conf .= "username-as-common-name\n";
+				$conf .= "auth-user-pass-verify /etc/inc/openvpn.auth-user.php via-env\n";
+				break;
 		}
 
 		// The local port to listen on
@@ -331,33 +366,52 @@ EOD;
 		// The management port to listen on
 		$conf .= "management 127.0.0.1 {$settings['local_port']}\n";
 
-		if (!empty($settings['maxclients'])) 
+		if ($settings['maxclients'])
 			$conf .= "max-clients {$settings['maxclients']}\n";
 
-		openvpn_add_dhcpopts($settings, $conf);
+		// Can we push routes
+		if ($settings['local_network']) {
+			list($ip, $mask) = explode('/', $settings['local_network']);
+			$mask = gen_subnet_mask($mask);
+			$conf .= "push \"route $ip $mask\"\n";
+		}
+
+		// Configure client dhcp options
+		switch($settings['mode']) {
+			case 'server_tls':
+			case 'server_user':
+			case 'server_tls_user':
+				openvpn_add_dhcpopts($settings, $conf);
+				break;
+		}
 	}
 
-	if ($mode == 'client') {
+	// client specific settings
 
-		// The remote server
-		$conf .= "remote {$settings['server_addr']} {$settings['server_port']}\n";
+	if ($mode == 'client') {
 
-		if ($settings['auth_method'] == 'pki')
-			$conf .= "client\n";
+		// configure p2p mode
+		switch($settings['mode']) {
+			case 'p2p_tls':
+				$conf .= "tls-client\n";
+			case 'shared_key':
+				$conf .= "client\n";
+				break;
+		}
 
-		// FIXME : This should be a gui option
 		// The port we'll listen at
 		if ($settings['local_port'])
 			$conf .= "lport {$settings['local_port']}\n";
 		else
 			$conf .= "nobind\n";
 
+		// The remote server
+		$conf .= "remote {$settings['server_addr']} {$settings['server_port']}\n";
+
 		if (!empty($settings['use_shaper']))
 			$conf .= "shaper {$settings['use_shaper']}\n";
 
 		if (!empty($settings['tunnel_network'])) {
-
-			// Configure the IPs according to the address pool
 			list($ip, $mask) = explode('/', $settings['tunnel_network']);
 			$mask = gen_subnet_mask($mask);
 			$baselong = ip2long($ip) & ip2long($mask);
@@ -366,41 +420,38 @@ EOD;
 			$conf .= "ifconfig $ip2 $ip1\n";
 		}
 
-		if ($settings['proxy_addr']) {
-			/* ;http-proxy-retry # retry on connection failures */
+		if ($settings['proxy_addr'])
 			$conf .= "http-proxy {$settings['proxy_addr']} {$settings['proxy_port']}\n";
-		}
 	}
 
-	// Add the routes if they're set
-	if (!empty($settings['remote_network'])) {
+	// Add a remote network route if set
+	if ($settings['remote_network']) {
 		list($ip, $mask) = explode('/', $settings['remote_network']);
 		$mask = gen_subnet_mask($mask);
 		$conf .= "route $ip $mask\n";
 	}
 
 	// Write the settings for the keys
-	if ($settings['auth_method'] == 'shared_key')
-		openvpn_add_keyfile($settings['shared_key'], $conf, $mode_id, "secret");
-
-	if ($settings['auth_method'] == 'pki') {
-
-		$ca = lookup_ca($settings['caref']);
-		$cert = lookup_cert($settings['certref']);
-
-		openvpn_add_keyfile($ca['crt'], $conf, $mode_id, "ca");
-		openvpn_add_keyfile($cert['crt'], $conf, $mode_id, "cert");
-		openvpn_add_keyfile($cert['prv'], $conf, $mode_id, "key");
-
-		if ($mode == 'server') {
-			$path_ovdh = $g['varetc_path']."/openvpn/dh-parameters";
-			$conf .= "dh {$path_ovdh}\n";
-		}
-
-		if ($settings['crl'])
-			openvpn_add_keyfile($settings['crl'], $conf, $mode_id, "crl-verify");
-		if ($settings['tls']) 
-			openvpn_add_keyfile($settings['tls'], $conf, $mode_id, "tls-auth");
+	switch($settings['mode']) {
+		case 'p2p_shared_key':
+			openvpn_add_keyfile($settings['shared_key'], $conf, $mode_id, "secret");
+			break;
+		case 'p2p_tls':
+		case 'server_tls':
+		case 'server_tls_user':
+			$ca = lookup_ca($settings['caref']);
+			openvpn_add_keyfile($ca['crt'], $conf, $mode_id, "ca");
+		case 'server_user':
+			$cert = lookup_cert($settings['certref']);
+			openvpn_add_keyfile($cert['crt'], $conf, $mode_id, "cert");
+			openvpn_add_keyfile($cert['prv'], $conf, $mode_id, "key");
+			if ($mode == 'server')
+				$conf .= "dh {$g['varetc_path']}/openvpn/dh-parameters\n";
+			if ($settings['crl'])
+				openvpn_add_keyfile($settings['crl'], $conf, $mode_id, "crl-verify");
+			if ($settings['tls'])
+				openvpn_add_keyfile($settings['tls'], $conf, $mode_id, "tls-auth");
+			break;
 	}
 
 	if ($settings['compression'])
-- 
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