diff options
Diffstat (limited to 'src/leap/bitmask/vpn/helpers/osx/bitmask-helper')
| -rwxr-xr-x | src/leap/bitmask/vpn/helpers/osx/bitmask-helper | 438 |
1 files changed, 438 insertions, 0 deletions
diff --git a/src/leap/bitmask/vpn/helpers/osx/bitmask-helper b/src/leap/bitmask/vpn/helpers/osx/bitmask-helper new file mode 100755 index 00000000..2990219f --- /dev/null +++ b/src/leap/bitmask/vpn/helpers/osx/bitmask-helper @@ -0,0 +1,438 @@ +#!/usr/bin/env python +# -*- coding: utf-8 -*- +# +# Author: Kali Kaneko +# Copyright (C) 2015-2017 LEAP Encryption Access Project +# +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +""" +This is a privileged helper script for safely running certain commands as root +under OSX. + +It should be run by launchd, and it exposes a Unix Domain Socket to where +the following commmands can be written by the Bitmask application: + + firewall_start [restart] GATEWAY1 GATEWAY2 ... + firewall_stop + openvpn_start CONFIG1 CONFIG1 ... + openvpn_stop + fw_email_start uid + fw_email_stop + +To load it manually: + + sudo launchctl load /Library/LaunchDaemons/se.leap.bitmask-helper + +To see the loaded rules: + + sudo pfctl -s rules -a bitmask + +To test the commands, you can write directly to the unix socket. Remember to +terminate the command properly: + + echo 'firewall_stop/CMD' | socat - UNIX-CONNECT:/tmp/bitmask-helper.socket + +""" +import os +import socket +import signal +import subprocess +import syslog +import threading + +from commands import getoutput as exec_cmd +from functools import partial + +import daemon + +VERSION = "1" +SCRIPT = "bitmask-helper" +NAMESERVER = "10.42.0.1" +BITMASK_ANCHOR = "com.apple/250.BitmaskFirewall" +BITMASK_ANCHOR_EMAIL = "bitmask_email" + +OPENVPN_USER = 'nobody' +OPENVPN_GROUP = 'nogroup' +LEAPOPENVPN = 'LEAPOPENVPN' +APP_PATH = '/Applications/Bitmask.app/' +RESOURCES_PATH = APP_PATH + 'Contents/Resources/' +OPENVPN_LEAP_BIN = RESOURCES_PATH + 'openvpn.leap' + +FIXED_FLAGS = [ + "--setenv", "LEAPOPENVPN", "1", + "--nobind", + "--client", + "--tls-client", + "--remote-cert-tls", "server", + "--management-signal", + "--script-security", "1", + "--user", "nobody", + "--remap-usr1", "SIGTERM", + "--group", OPENVPN_GROUP, +] + +ALLOWED_FLAGS = { + "--remote": ["IP", "NUMBER", "PROTO"], + "--tls-cipher": ["CIPHER"], + "--cipher": ["CIPHER"], + "--auth": ["CIPHER"], + "--management": ["DIR", "UNIXSOCKET"], + "--management-client-user": ["USER"], + "--cert": ["FILE"], + "--key": ["FILE"], + "--ca": ["FILE"], + "--fragment": ["NUMBER"] +} + +PARAM_FORMATS = { + "NUMBER": lambda s: re.match("^\d+$", s), + "PROTO": lambda s: re.match("^(tcp|udp)$", s), + "IP": lambda s: is_valid_address(s), + "CIPHER": lambda s: re.match("^[A-Z0-9-]+$", s), + "USER": lambda s: re.match( + "^[a-zA-Z0-9_\.\@][a-zA-Z0-9_\-\.\@]*\$?$", s), # IEEE Std 1003.1-2001 + "FILE": lambda s: os.path.isfile(s), + "DIR": lambda s: os.path.isdir(os.path.split(s)[0]), + "UNIXSOCKET": lambda s: s == "unix", + "UID": lambda s: re.match("^[a-zA-Z0-9]+$", s) +} + +# +# paths (must use absolute paths, since this script is run as root) +# + +PFCTL = '/sbin/pfctl' +ROUTE = '/sbin/route' +AWK = '/usr/bin/awk' +GREP = '/usr/bin/grep' +CAT = '/bin/cat' + +UID = os.getuid() +SERVER_ADDRESS = '/tmp/bitmask-helper.socket' + + +# +# COMMAND DISPATCH +# + +def serve_forever(): + try: + os.unlink(SERVER_ADDRESS) + except OSError: + if os.path.exists(SERVER_ADDRESS): + raise + + syslog.syslog(syslog.LOG_WARNING, "serving forever") + # XXX should check permissions on the socket file + sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) + sock.bind(SERVER_ADDRESS) + sock.listen(1) + syslog.syslog(syslog.LOG_WARNING, "Binded to %s" % SERVER_ADDRESS) + + while True: + connection, client_address = sock.accept() + thread = threading.Thread(target=handle_command, args=[connection]) + thread.daemon = True + thread.start() + +def recv_until_marker(sock): + end = '/CMD' + total_data=[] + data='' + while True: + data=sock.recv(8192) + if end in data: + total_data.append(data[:data.find(end)]) + break + total_data.append(data) + if len(total_data)>1: + #check if end_of_data was split + last_pair=total_data[-2]+total_data[-1] + if end in last_pair: + total_data[-2] = last_pair[:last_pair.find(end)] + total_data.pop() + break + return ''.join(total_data) + + +def handle_command(sock): + syslog.syslog(syslog.LOG_WARNING, "handle") + + received = recv_until_marker(sock) + syslog.syslog(syslog.LOG_WARNING, "GOT -----> %s" % received) + line = received.replace('\n', '').split(' ') + + command, args = line[0], line[1:] + syslog.syslog(syslog.LOG_WARNING, 'command %s' % (command)) + + cmd_dict = { + 'firewall_start': (firewall_start, args), + 'firewall_stop': (firewall_stop, []), + 'firewall_isup': (firewall_isup, []), + 'openvpn_start': (openvpn_start, args), + 'openvpn_stop': (openvpn_stop, []), + 'openvpn_force_stop': (openvpn_stop, ['KILL']), + 'openvpn_set_watcher': (openvpn_set_watcher, args) + } + + cmd_call = cmd_dict.get(command, None) + syslog.syslog(syslog.LOG_WARNING, 'call: %s' % (str(cmd_call))) + try: + if cmd_call: + syslog.syslog( + syslog.LOG_WARNING, 'GOT "%s"' % (command)) + cmd, args = cmd_call + if args: + cmd = partial(cmd, *args) + + # TODO Use a MUTEX in here + result = cmd() + syslog.syslog(syslog.LOG_WARNING, "Executed") + syslog.syslog(syslog.LOG_WARNING, "Result: %s" % (str(result))) + if result == 'YES': + sock.sendall("%s: YES\n" % command) + elif result == 'NO': + sock.sendall("%s: NO\n" % command) + else: + sock.sendall("%s: OK\n" % command) + + else: + syslog.syslog(syslog.LOG_WARNING, 'invalid command: %s' % (command,)) + sock.sendall("%s: ERROR\n" % command) + except Exception as exc: + syslog.syslog(syslog.LOG_WARNING, "error executing function %r" % (exc)) + finally: + sock.close() + + + +# +# OPENVPN +# + + +openvpn_proc = None +openvpn_watcher_pid = None + + +def openvpn_start(*args): + """ + Sanitize input and run openvpn as a subprocess of this long-running daemon. + Keeps a reference to the subprocess Popen class instance. + + :param args: arguments to be passed to openvpn + :type args: list + """ + syslog.syslog(syslog.LOG_WARNING, "OPENVPN START") + opts = list(args[1:]) + + opts += ['--dhcp-option', 'DNS', '10.42.0.1', + '--up', RESOURCES_PATH + 'client.up.sh', + '--down', RESOURCES_PATH + 'client.down.sh'] + opts += ["--dev", "tun"] + binary = [RESOURCES_PATH + 'openvpn.leap'] + cmd = binary + opts + #syslog.syslog(syslog.LOG_WARNING, 'LAUNCHING VPN: ' + ' '.join(cmd)) + + # TODO sanitize options + global openvpn_proc + openvpn_proc = subprocess.Popen(cmd, shell=False, bufsize=-1) + #try: + # result = subprocess.check_output(cmd, shell=False, stderr=subprocess.STDOUT) + #except Exception as exc: + # syslog.syslog(syslog.LOG_WARNING, exc.output) + #syslog.syslog(syslog.LOG_WARNING, "OpenVPN PID: %s" % str(openvpn_proc.pid)) + + +def openvpn_stop(sig='TERM'): + """ + Stop the openvpn that has been launched by this privileged helper. + + :param args: arguments to openvpn + :type args: list + """ + global openvpn_proc + + if openvpn_proc: + syslog.syslog(syslog.LOG_WARNING, "OVPN PROC: %s" % str(openvpn_proc.pid)) + + if sig == 'KILL': + stop_signal = signal.SIGKILL + openvpn_proc.kill() + elif sig == 'TERM': + stop_signal = signal.SIGTERM + openvpn_proc.terminate() + + returncode = openvpn_proc.wait() + syslog.syslog(syslog.LOG_WARNING, "openvpn return code: %s" % str(returncode)) + syslog.syslog(syslog.LOG_WARNING, "openvpn_watcher_pid: %s" % str(openvpn_watcher_pid)) + if openvpn_watcher_pid: + os.kill(openvpn_watcher_pid, stop_signal) + + +def openvpn_set_watcher(pid, *args): + global openvpn_watcher_pid + openvpn_watcher_pid = int(pid) + syslog.syslog(syslog.LOG_WARNING, "Watcher PID: %s" % pid) + + +# +# FIREWALL +# + + +def firewall_start(*gateways): + """ + Bring up the firewall. + + :param gws: list of gateways, to be sanitized. + :type gws: list + """ + + gateways = get_gateways(gateways) + + if not gateways: + return False + + _enable_pf() + _reset_bitmask_gateways_table(gateways) + + default_device = _get_default_device() + _load_bitmask_anchor(default_device) + + +def firewall_stop(): + """ + Flush everything from anchor bitmask + """ + cmd = '{pfctl} -a {anchor} -F all'.format( + pfctl=PFCTL, anchor=BITMASK_ANCHOR) + return exec_cmd(cmd) + + +def firewall_isup(): + """ + Return YES if anchor bitmask is loaded with rules + """ + syslog.syslog(syslog.LOG_WARNING, 'PID---->%s' % os.getpid()) + cmd = '{pfctl} -s rules -a {anchor} | wc -l'.format( + pfctl=PFCTL, anchor=BITMASK_ANCHOR) + output = exec_cmd(cmd) + rules = output[-1] + if int(rules) > 0: + return 'YES' + else: + return 'NO' + + +def _enable_pf(): + exec_cmd('{pfctl} -e'.format(pfctl=PFCTL)) + + +def _reset_bitmask_gateways_table(gateways): + cmd = '{pfctl} -a {anchor} -t bitmask_gateways -T delete'.format( + pfctl=PFCTL, anchor=BITMASK_ANCHOR) + output = exec_cmd(cmd) + + for gateway in gateways: + cmd = '{pfctl} -a {anchor} -t bitmask_gateways -T add {gw}'.format( + pfctl=PFCTL, anchor=BITMASK_ANCHOR, gw=gateway) + output = exec_cmd(cmd) + syslog.syslog(syslog.LOG_WARNING, "adding gw %s" % gateway) + + #cmd = '{pfctl} -a {anchor} -t bitmask_nameservers -T delete'.format( + # pfctl=PFCTL, anchor=BITMASK_ANCHOR) + #output = exec_cmd(cmd) + + cmd = '{pfctl} -a {anchor} -t bitmask_gateways -T add {ns}'.format( + pfctl=PFCTL, anchor=BITMASK_ANCHOR, ns=NAMESERVER) + output = exec_cmd(cmd) + syslog.syslog(syslog.LOG_WARNING, "adding ns %s" % NAMESERVER) + +def _load_bitmask_anchor(default_device): + cmd = ('{pfctl} -D default_device={defaultdevice} ' + '-a {anchor} -f {rulefile}').format( + pfctl=PFCTL, defaultdevice=default_device, + anchor=BITMASK_ANCHOR, + rulefile=RESOURCES_PATH + 'bitmask-helper/bitmask.pf.conf') + syslog.syslog(syslog.LOG_WARNING, "LOADING CMD: %s" % cmd) + return exec_cmd(cmd) + + +def _get_default_device(): + """ + Retrieve the current default network device. + + :rtype: str + """ + cmd_def_device = ( + '{route} -n get -net default | ' + '{grep} interface | {awk} "{{print $2}}"').format( + route=ROUTE, grep=GREP, awk=AWK) + iface = exec_cmd(cmd_def_device) + iface = iface.replace("interface: ", "").strip() + syslog.syslog(syslog.LOG_WARNING, "default device %s" % iface) + return iface + + + +# +# UTILITY +# + + +def is_valid_address(value): + """ + Validate that the passed ip is a valid IP address. + + :param value: the value to be validated + :type value: str + :rtype: bool + """ + try: + socket.inet_aton(value) + return True + except Exception: + syslog.syslog(syslog.LOG_WARNING, 'MALFORMED IP: %s!' % (value)) + return False + + +# +# FIREWALL +# + + +def get_gateways(gateways): + """ + Filter a passed sequence of gateways, returning only the valid ones. + + :param gateways: a sequence of gateways to filter. + :type gateways: iterable + :rtype: iterable + """ + syslog.syslog(syslog.LOG_WARNING, 'Filtering %s' % str(gateways)) + result = filter(is_valid_address, gateways) + if not result: + syslog.syslog(syslog.LOG_ERR, 'No valid gateways specified') + return False + else: + return result + + + +if __name__ == "__main__": + with daemon.DaemonContext(): + syslog.syslog(syslog.LOG_WARNING, "Serving...") + serve_forever() |