pfSense

#!/usr/local/bin/php-cgi -f

<?php

/*

 * sshd

 *

 * part of pfSense (https://www.pfsense.org)

 * Copyright (c) 2004 Fred Mol <fredmol@xs4all.nl>.

 * Copyright (c) 2004-2016 Rubicon Communications, LLC (Netgate)

 * 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.

 *

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgment:

 *    "This product includes software developed by the pfSense Project

 *    for use in the pfSense® software distribution. (http://www.pfsense.org/).

 *

 * 4. The names "pfSense" and "pfSense Project" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission. For written permission, please contact

 *    coreteam@pfsense.org.

 *

 * 5. Products derived from this software may not be called "pfSense"

 *    nor may "pfSense" appear in their names without prior written

 *    permission of the Electric Sheep Fencing, LLC.

 *

 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *

 * "This product includes software developed by the pfSense Project

 * for use in the pfSense software distribution (http://www.pfsense.org/).

 *

 * THIS SOFTWARE IS PROVIDED BY THE pfSense PROJECT ``AS IS'' AND ANY

 * EXPRESSED 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 pfSense PROJECT OR

 * ITS CONTRIBUTORS 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.

 */

require_once("globals.inc");

require_once("config.inc");

require_once("functions.inc");

require_once("shaper.inc");

if (!isset($config['system']['enablesshd'])) {

	return;

}

/* are we already running?  if not, do conf_mount_rw(), otherwise it should already be rw */

if (!is_subsystem_dirty('sshdkeys')) {

	conf_mount_rw();

}

$sshConfigDir = "/etc/ssh";

$keys = array(

	array('type' => 'rsa',     'suffix' => 'rsa_'),

	array('type' => 'ed25519', 'suffix' => 'ed25519_')

);

$keyfiles = array();

foreach ($keys as $key) {

	$keyfiles[] = "ssh_host_{$key['suffix']}key";

	$keyfiles[] = "ssh_host_{$key['suffix']}key.pub";

}

/* restore ssh data for nanobsd platform */

if ($g['platform'] == "nanobsd" and file_exists("/conf/sshd/ssh_host_key") and !file_exists("{$sshConfigDir}/ssh_host_key.pub")) {

	echo "Restoring SSH from /conf/sshd/";

	exec("/bin/cp -p /conf/sshd/* {$sshConfigDir}/");

	/* make sure host private key permissions aren't too open so sshd won't complain */

	foreach ($keyfiles as $f2c) {

		if (file_exists("{$sshConfigDir}/{$f2c}")) {

			chmod("{$sshConfigDir}/{$f2c}", 0600);

		}

	}

}

/*    if any of these files are 0 bytes then they are corrupted.

 *    remove them

 */

foreach ($keyfiles as $f2c) {

	if (!file_exists("{$sshConfigDir}/{$f2c}") || filesize("{$sshConfigDir}/{$f2c}") == 0) {

		/* Make sure we remove both files */

		unlink_if_exists($sshConfigDir . '/' . basename($f2c, ".pub"));

		unlink_if_exists($sshConfigDir . '/' . $f2c);

	}

}

if (!is_dir("/var/empty")) {

	/* make ssh home directory */

	mkdir("/var/empty", 0555);

}

if (!file_exists("/var/log/lastlog")) {

	/* Login related files. */

	@touch("/var/log/lastlog");

}

if (is_array($config['system']['ssh']) && !empty($config['system']['ssh']['port'])) {

	$sshport = $config['system']['ssh']['port'];

} else {

	$sshport = 22;

}

/* Include default configuration for pfSense */

/* Taken from https://stribika.github.io/2015/01/04/secure-secure-shell.html */

$sshconf = "# This file is automatically generated at startup\n";

$sshconf .= "KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256\n";

/* Run the server on another port if we have one defined */

$sshconf .= "Port $sshport\n";

/* Only allow protocol 2, because we say so */

$sshconf .= "Protocol 2\n";

foreach ($keys as $key) {

	$sshconf .= "HostKey {$sshConfigDir}/ssh_host_{$key['suffix']}key\n";

}

$sshconf .= "Compression yes\n";

$sshconf .= "ClientAliveInterval 30\n";

$sshconf .= "PermitRootLogin yes\n";

if (isset($config['system']['ssh']['sshdkeyonly'])) {

	$sshconf .= "# Login via Key only\n";

	$sshconf .= "ChallengeResponseAuthentication no\n";

	$sshconf .= "PasswordAuthentication no\n";

	$sshconf .= "PubkeyAuthentication yes\n";

	$sshconf .= "UsePAM no\n";

} else {

	$sshconf .= "# Login via Key and Password\n";

	$sshconf .= "ChallengeResponseAuthentication yes\n";

	$sshconf .= "PasswordAuthentication yes\n";

	$sshconf .= "PubkeyAuthentication yes\n";

}

$sshconf .= "UseDNS no\n";

$sshconf .= "LoginGraceTime 30s\n";

/* Hide FreeBSD version */

$sshconf .= "VersionAddendum none\n";

$sshconf .= "X11Forwarding no\n";

$sshconf .= "Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr\n";

$sshconf .= "MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-ripemd160-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,hmac-ripemd160,umac-128@openssh.com\n";

$sshconf .= "# override default of no subsystems\n";

$sshconf .= "Subsystem\tsftp\t/usr/libexec/sftp-server\n";

/* Apply package SSHDCond settings if config file exists */

if (file_exists("/etc/sshd_extra")) {

	$fdExtra = fopen("/etc/sshd_extra", 'r');

	$szExtra = fread($fdExtra, 1048576); // Read up to 1MB from extra file

	$sshconf .= $szExtra;

	fclose($fdExtra);

}

/* Write the new sshd config file */

@file_put_contents("{$sshConfigDir}/sshd_config", $sshconf);

/* mop up from a badly implemented ssh keys -> cf backup */

if ($config['ssh']['dsa_key'] <> "") {

	unset($config['ssh']['dsa_key']);

	unset($config['ssh']['ecdsa_key']);

	unset($config['ssh']['ed25519_key']);

	unset($config['ssh']['rsa_key']);

	unset($config['ssh']['rsa1_key']);

	unset($config['ssh']['dsa']);

	unset($config['ssh']['rsa']);

	unset($config['ssh']['rsa1']);

	unset($config['ssh']['ak']);

	write_config("Clearing SSH keys from config.xml");

}

/* are we already running?  if so exit */

if (is_subsystem_dirty('sshdkeys')) {

	unset($keys, $keyfiles);

	return;

}

// Check for all needed key files. If any are missing, the keys need to be regenerated.

$generate_keys = array();

foreach ($keys as $key) {

	if (!file_exists("{$sshConfigDir}/ssh_host_{$key['suffix']}key") ||

	    !file_exists("{$sshConfigDir}/ssh_host_{$key['suffix']}key.pub")) {

		$generate_keys[] = $key;

	}

}

if (!empty($generate_keys)) {

	/* remove previous keys and regen later */

	file_notice("SSH", "{$g['product_name']} has started creating missing SSH keys.  SSH Startup will be delayed.  Please note that reloading the filter rules and changes will be delayed until this operation is completed.", "SSH KeyGen", "");

	mark_subsystem_dirty('sshdkeys');

	echo " Generating Keys:\n";

	foreach ($generate_keys as $key) {

		$_gb = exec("/usr/bin/nice -n20 /usr/bin/ssh-keygen -t {$key['type']} -b 4096 -N '' -f {$sshConfigDir}/ssh_host_{$key['suffix']}key");

	}

	clear_subsystem_dirty('sshdkeys');

	file_notice("SSH", "{$g['product_name']} has completed creating your SSH keys.  SSH is now started.", "SSH Startup", "");

}

/* kill existing sshd process, server only, not the childs */

$sshd_pid = exec("ps ax | egrep '/usr/sbin/[s]shd' | awk '{print $1}'");

if ($sshd_pid <> "") {

	echo "stopping ssh process $sshd_pid \n";

	@posix_kill($sshd_pid, SIGTERM);

}

/* Launch new server process */

$status = mwexec("/usr/sbin/sshd");

if ($status <> 0) {

	file_notice("sshd_startup", "SSHD failed to start.", "SSHD Daemon", "");

	echo "error!\n";

} else {

	echo "done.\n";

}

// NanoBSD

if ($g['platform'] == "nanobsd") {

	if (!is_dir("/conf/sshd")) {

		mkdir("/conf/sshd", 0750);

	}

	$_gb = exec("/bin/cp -p {$sshConfigDir}/ssh_host* /conf/sshd");

}

conf_mount_ro();

unset($keys, $keyfiles);

?>