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Diffstat (limited to 'src/leap/bitmask/vpn/process.py')
| -rw-r--r-- | src/leap/bitmask/vpn/process.py | 920 |
1 files changed, 920 insertions, 0 deletions
diff --git a/src/leap/bitmask/vpn/process.py b/src/leap/bitmask/vpn/process.py new file mode 100644 index 0000000..05847e2 --- /dev/null +++ b/src/leap/bitmask/vpn/process.py @@ -0,0 +1,920 @@ +# -*- coding: utf-8 -*- +# process.py +# Copyright (C) 2013-2017 LEAP +# +# 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/>. + +""" +VPN Manager, spawned in a custom processProtocol. +""" + +import os +import shutil +import socket +import subprocess +import sys + +from itertools import chain, repeat + +import psutil +try: + # psutil < 2.0.0 + from psutil.error import AccessDenied as psutil_AccessDenied + PSUTIL_2 = False +except ImportError: + # psutil >= 2.0.0 + from psutil import AccessDenied as psutil_AccessDenied + PSUTIL_2 = True + +from twisted.internet import defer, protocol, reactor +from twisted.internet import error as internet_error +from twisted.internet.task import LoopingCall +from twisted.logger import Logger + +from leap.bitmask.vpn.constants import IS_MAC +from leap.bitmask.vpn.utils import first, force_eval +from leap.bitmask.vpn.utils import get_vpn_launcher +from leap.bitmask.vpn.launchers import linux +from leap.bitmask.vpn.udstelnet import UDSTelnet + +logger = Logger() + + +# OpenVPN verbosity level - from flags.py +OPENVPN_VERBOSITY = 1 + + +class VPNObserver(object): + """ + A class containing different patterns in the openvpn output that + we can react upon. + """ + + # TODO this is i18n-sensitive, right? + # in that case, we should add the translations :/ + # until we find something better. + + _events = { + 'NETWORK_UNREACHABLE': ( + 'Network is unreachable (code=101)',), + 'PROCESS_RESTART_TLS': ( + "SIGTERM[soft,tls-error]",), + 'PROCESS_RESTART_PING': ( + "SIGTERM[soft,ping-restart]",), + 'INITIALIZATION_COMPLETED': ( + "Initialization Sequence Completed",), + } + + def __init__(self, signaler=None): + self._signaler = signaler + + def watch(self, line): + """ + Inspects line searching for the different patterns. If a match + is found, try to emit the corresponding signal. + + :param line: a line of openvpn output + :type line: str + """ + chained_iter = chain(*[ + zip(repeat(key, len(l)), l) + for key, l in self._events.iteritems()]) + for event, pattern in chained_iter: + if pattern in line: + logger.debug('pattern matched! %s' % pattern) + break + else: + return + + sig = self._get_signal(event) + if sig is not None: + if self._signaler is not None: + self._signaler.signal(sig) + return + else: + logger.debug('We got %s event from openvpn output but we could ' + 'not find a matching signal for it.' % event) + + def _get_signal(self, event): + """ + Tries to get the matching signal from the eip signals + objects based on the name of the passed event (in lowercase) + + :param event: the name of the event that we want to get a signal for + :type event: str + :returns: a Signaler signal or None + :rtype: str or None + """ + if self._signaler is None: + return + sig = self._signaler + signals = { + "network_unreachable": sig.eip_network_unreachable, + "process_restart_tls": sig.eip_process_restart_tls, + "process_restart_ping": sig.eip_process_restart_ping, + "initialization_completed": sig.eip_connected + } + return signals.get(event.lower()) + + +class OpenVPNAlreadyRunning(Exception): + message = ("Another openvpn instance is already running, and could " + "not be stopped.") + + +class AlienOpenVPNAlreadyRunning(Exception): + message = ("Another openvpn instance is already running, and could " + "not be stopped because it was not launched by LEAP.") + + +class VPN(object): + """ + This is the high-level object that the GUI is dealing with. + It exposes the start and terminate methods. + + On start, it spawns a VPNProcess instance that will use a vpnlauncher + suited for the running platform and connect to the management interface + opened by the openvpn process, executing commands over that interface on + demand. + """ + TERMINATE_MAXTRIES = 10 + TERMINATE_WAIT = 1 # secs + + OPENVPN_VERB = "openvpn_verb" + + def __init__(self, **kwargs): + """ + Instantiate empty attributes and get a copy + of a QObject containing the QSignals that we will pass along + to the VPNManager. + """ + self._vpnproc = None + self._pollers = [] + + self._signaler = kwargs['signaler'] + # self._openvpn_verb = flags.OPENVPN_VERBOSITY + self._openvpn_verb = None + + self._user_stopped = False + self._remotes = kwargs['remotes'] + + def start(self, *args, **kwargs): + """ + Starts the openvpn subprocess. + + :param args: args to be passed to the VPNProcess + :type args: tuple + + :param kwargs: kwargs to be passed to the VPNProcess + :type kwargs: dict + """ + logger.debug('VPN: start') + self._user_stopped = False + self._stop_pollers() + kwargs['openvpn_verb'] = self._openvpn_verb + kwargs['signaler'] = self._signaler + kwargs['remotes'] = self._remotes + + # start the main vpn subprocess + vpnproc = VPNProcess(*args, **kwargs) + + if vpnproc.get_openvpn_process(): + logger.info("Another vpn process is running. Will try to stop it.") + vpnproc.stop_if_already_running() + + # FIXME it would be good to document where the + # errors here are catched, since we currently handle them + # at the frontend layer. This *should* move to be handled entirely + # in the backend. + # exception is indeed technically catched in backend, then converted + # into a signal, that is catched in the eip_status widget in the + # frontend, and converted into a signal to abort the connection that is + # sent to the backend again. + + # the whole exception catching should be done in the backend, without + # the ping-pong to the frontend, and without adding any logical checks + # in the frontend. We should just communicate UI changes to frontend, + # and abstract us away from anything else. + try: + cmd = vpnproc.getCommand() + except Exception as e: + logger.error("Error while getting vpn command... {0!r}".format(e)) + raise + + env = os.environ + for key, val in vpnproc.vpn_env.items(): + env[key] = val + + reactor.spawnProcess(vpnproc, cmd[0], cmd, env) + self._vpnproc = vpnproc + + # add pollers for status and state + # this could be extended to a collection of + # generic watchers + + poll_list = [LoopingCall(vpnproc.pollStatus), + LoopingCall(vpnproc.pollState)] + self._pollers.extend(poll_list) + self._start_pollers() + + def bitmask_root_vpn_down(self): + """ + Bring openvpn down using the privileged wrapper. + """ + if IS_MAC: + # We don't support Mac so far + return True + BM_ROOT = force_eval(linux.LinuxVPNLauncher.BITMASK_ROOT) + + # FIXME -- port to processProtocol + exitCode = subprocess.call(["pkexec", + BM_ROOT, "openvpn", "stop"]) + return True if exitCode is 0 else False + + def _kill_if_left_alive(self, tries=0): + """ + Check if the process is still alive, and send a + SIGKILL after a timeout period. + + :param tries: counter of tries, used in recursion + :type tries: int + """ + while tries < self.TERMINATE_MAXTRIES: + if self._vpnproc.transport.pid is None: + logger.debug("Process has been happily terminated.") + return + else: + logger.debug("Process did not die, waiting...") + + tries += 1 + reactor.callLater(self.TERMINATE_WAIT, + self._kill_if_left_alive, tries) + return + + # after running out of patience, we try a killProcess + logger.debug("Process did not died. Sending a SIGKILL.") + try: + self.killit() + except OSError: + logger.error("Could not kill process!") + + def killit(self): + """ + Sends a kill signal to the process. + """ + self._stop_pollers() + if self._vpnproc is None: + logger.debug("There's no vpn process running to kill.") + else: + self._vpnproc.aborted = True + self._vpnproc.killProcess() + + def terminate(self, shutdown=False, restart=False): + """ + Stops the openvpn subprocess. + + Attempts to send a SIGTERM first, and after a timeout + it sends a SIGKILL. + + :param shutdown: whether this is the final shutdown + :type shutdown: bool + :param restart: whether this stop is part of a hard restart. + :type restart: bool + """ + self._stop_pollers() + + # First we try to be polite and send a SIGTERM... + if self._vpnproc is not None: + # We assume that the only valid stops are initiated + # by an user action, not hard restarts + self._user_stopped = not restart + self._vpnproc.is_restart = restart + + self._sentterm = True + self._vpnproc.terminate_openvpn(shutdown=shutdown) + + # ...but we also trigger a countdown to be unpolite + # if strictly needed. + reactor.callLater( + self.TERMINATE_WAIT, self._kill_if_left_alive) + else: + logger.debug("VPN is not running.") + + def _start_pollers(self): + """ + Iterate through the registered observers + and start the looping call for them. + """ + for poller in self._pollers: + poller.start(VPNManager.POLL_TIME) + + def _stop_pollers(self): + """ + Iterate through the registered observers + and stop the looping calls if they are running. + """ + for poller in self._pollers: + if poller.running: + poller.stop() + self._pollers = [] + + +class VPNManager(object): + """ + This is a mixin that we use in the VPNProcess class. + Here we get together all methods related with the openvpn management + interface. + + A copy of a QObject containing signals as attributes is passed along + upon initialization, and we use that object to emit signals to qt-land. + + For more info about management methods:: + + zcat `dpkg -L openvpn | grep management` + """ + + # Timers, in secs + # NOTE: We need to set a bigger poll time in OSX because it seems + # openvpn malfunctions when you ask it a lot of things in a short + # amount of time. + POLL_TIME = 2.5 if IS_MAC else 1.0 + CONNECTION_RETRY_TIME = 1 + + def __init__(self, signaler=None): + """ + Initializes the VPNManager. + + :param signaler: Signaler object used to send notifications to the + backend + :type signaler: backend.Signaler + """ + self._tn = None + self._signaler = signaler + self._aborted = False + + @property + def aborted(self): + return self._aborted + + @aborted.setter + def aborted(self, value): + self._aborted = value + + def _seek_to_eof(self): + """ + Read as much as available. Position seek pointer to end of stream + """ + try: + self._tn.read_eager() + except EOFError: + logger.debug("Could not read from socket. Assuming it died.") + return + + def _send_command(self, command, until=b"END"): + """ + Sends a command to the telnet connection and reads until END + is reached. + + :param command: command to send + :type command: str + + :param until: byte delimiter string for reading command output + :type until: byte str + + :return: response read + :rtype: list + """ + # leap_assert(self._tn, "We need a tn connection!") + + try: + self._tn.write("%s\n" % (command,)) + buf = self._tn.read_until(until, 2) + self._seek_to_eof() + blist = buf.split('\r\n') + if blist[-1].startswith(until): + del blist[-1] + return blist + else: + return [] + + except socket.error: + # XXX should get a counter and repeat only + # after mod X times. + logger.warning('socket error (command was: "%s")' % (command,)) + self._close_management_socket(announce=False) + logger.debug('trying to connect to management again') + self.try_to_connect_to_management(max_retries=5) + return [] + + # XXX should move this to a errBack! + except Exception as e: + logger.warning("Error sending command %s: %r" % + (command, e)) + return [] + + def _close_management_socket(self, announce=True): + """ + Close connection to openvpn management interface. + """ + logger.debug('closing socket') + if announce: + self._tn.write("quit\n") + self._tn.read_all() + self._tn.get_socket().close() + self._tn = None + + def _connect_management(self, socket_host, socket_port): + """ + Connects to the management interface on the specified + socket_host socket_port. + + :param socket_host: either socket path (unix) or socket IP + :type socket_host: str + + :param socket_port: either string "unix" if it's a unix + socket, or port otherwise + :type socket_port: str + """ + if self.is_connected(): + self._close_management_socket() + + try: + self._tn = UDSTelnet(socket_host, socket_port) + + # XXX make password optional + # specially for win. we should generate + # the pass on the fly when invoking manager + # from conductor + + # self.tn.read_until('ENTER PASSWORD:', 2) + # self.tn.write(self.password + '\n') + # self.tn.read_until('SUCCESS:', 2) + if self._tn: + self._tn.read_eager() + + # XXX move this to the Errback + except Exception as e: + logger.warning("Could not connect to OpenVPN yet: %r" % (e,)) + self._tn = None + + def _connectCb(self, *args): + """ + Callback for connection. + + :param args: not used + """ + if self._tn: + logger.info('Connected to management') + else: + logger.debug('Cannot connect to management...') + + def _connectErr(self, failure): + """ + Errorback for connection. + + :param failure: Failure + """ + logger.warning(failure) + + def connect_to_management(self, host, port): + """ + Connect to a management interface. + + :param host: the host of the management interface + :type host: str + + :param port: the port of the management interface + :type port: str + + :returns: a deferred + """ + self.connectd = defer.maybeDeferred( + self._connect_management, host, port) + self.connectd.addCallbacks(self._connectCb, self._connectErr) + return self.connectd + + def is_connected(self): + """ + Returns the status of the management interface. + + :returns: True if connected, False otherwise + :rtype: bool + """ + return True if self._tn else False + + def try_to_connect_to_management(self, retry=0, max_retries=None): + """ + Attempts to connect to a management interface, and retries + after CONNECTION_RETRY_TIME if not successful. + + :param retry: number of the retry + :type retry: int + """ + if max_retries and retry > max_retries: + logger.warning("Max retries reached while attempting to connect " + "to management. Aborting.") + self.aborted = True + return + + # _alive flag is set in the VPNProcess class. + if not self._alive: + logger.debug('Tried to connect to management but process is ' + 'not alive.') + return + logger.debug('trying to connect to management') + if not self.aborted and not self.is_connected(): + self.connect_to_management(self._socket_host, self._socket_port) + reactor.callLater( + self.CONNECTION_RETRY_TIME, + self.try_to_connect_to_management, retry + 1) + + def _parse_state_and_notify(self, output): + """ + Parses the output of the state command and emits state_changed + signal when the state changes. + + :param output: list of lines that the state command printed as + its output + :type output: list + """ + for line in output: + stripped = line.strip() + if stripped == "END": + continue + parts = stripped.split(",") + if len(parts) < 5: + continue + ts, status_step, ok, ip, remote = parts + + state = status_step + if state != self._last_state: + if self._signaler is not None: + self._signaler.signal(self._signaler.eip_state_changed, state) + self._last_state = state + + def _parse_status_and_notify(self, output): + """ + Parses the output of the status command and emits + status_changed signal when the status changes. + + :param output: list of lines that the status command printed + as its output + :type output: list + """ + tun_tap_read = "" + tun_tap_write = "" + + for line in output: + stripped = line.strip() + if stripped.endswith("STATISTICS") or stripped == "END": + continue + parts = stripped.split(",") + if len(parts) < 2: + continue + + text, value = parts + # text can be: + # "TUN/TAP read bytes" + # "TUN/TAP write bytes" + # "TCP/UDP read bytes" + # "TCP/UDP write bytes" + # "Auth read bytes" + + if text == "TUN/TAP read bytes": + tun_tap_read = value # download + elif text == "TUN/TAP write bytes": + tun_tap_write = value # upload + + status = (tun_tap_read, tun_tap_write) + if status != self._last_status: + if self._signaler is not None: + self._signaler.signal(self._signaler.eip_status_changed, status) + self._last_status = status + + def get_state(self): + """ + Notifies the gui of the output of the state command over + the openvpn management interface. + """ + if self.is_connected(): + return self._parse_state_and_notify(self._send_command("state")) + + def get_status(self): + """ + Notifies the gui of the output of the status command over + the openvpn management interface. + """ + if self.is_connected(): + return self._parse_status_and_notify(self._send_command("status")) + + @property + def vpn_env(self): + """ + Return a dict containing the vpn environment to be used. + """ + return self._launcher.get_vpn_env() + + def terminate_openvpn(self, shutdown=False): + """ + Attempts to terminate openvpn by sending a SIGTERM. + """ + if self.is_connected(): + self._send_command("signal SIGTERM") + if shutdown: + self._cleanup_tempfiles() + + def _cleanup_tempfiles(self): + """ + Remove all temporal files we might have left behind. + + Iif self.port is 'unix', we have created a temporal socket path that, + under normal circumstances, we should be able to delete. + """ + if self._socket_port == "unix": + logger.debug('cleaning socket file temp folder') + tempfolder = first(os.path.split(self._socket_host)) + if tempfolder and os.path.isdir(tempfolder): + try: + shutil.rmtree(tempfolder) + except OSError: + logger.error('could not delete tmpfolder %s' % tempfolder) + + def get_openvpn_process(self): + """ + Looks for openvpn instances running. + + :rtype: process + """ + openvpn_process = None + for p in psutil.process_iter(): + try: + # XXX Not exact! + # Will give false positives. + # we should check that cmdline BEGINS + # with openvpn or with our wrapper + # (pkexec / osascript / whatever) + + # This needs more work, see #3268, but for the moment + # we need to be able to filter out arguments in the form + # --openvpn-foo, since otherwise we are shooting ourselves + # in the feet. + + if PSUTIL_2: + cmdline = p.cmdline() + else: + cmdline = p.cmdline + if any(map(lambda s: s.find( + "LEAPOPENVPN") != -1, cmdline)): + openvpn_process = p + break + except psutil_AccessDenied: + pass + return openvpn_process + + def stop_if_already_running(self): + """ + Checks if VPN is already running and tries to stop it. + + Might raise OpenVPNAlreadyRunning. + + :return: True if stopped, False otherwise + + """ + process = self.get_openvpn_process() + if not process: + logger.debug('Could not find openvpn process while ' + 'trying to stop it.') + return + + logger.debug("OpenVPN is already running, trying to stop it...") + cmdline = process.cmdline + + manag_flag = "--management" + if isinstance(cmdline, list) and manag_flag in cmdline: + # we know that our invocation has this distinctive fragment, so + # we use this fingerprint to tell other invocations apart. + # this might break if we change the configuration path in the + # launchers + smellslikeleap = lambda s: "leap" in s and "providers" in s + + if not any(map(smellslikeleap, cmdline)): + logger.debug("We cannot stop this instance since we do not " + "recognise it as a leap invocation.") + raise AlienOpenVPNAlreadyRunning + + try: + index = cmdline.index(manag_flag) + host = cmdline[index + 1] + port = cmdline[index + 2] + logger.debug("Trying to connect to %s:%s" + % (host, port)) + self.connect_to_management(host, port) + + # XXX this has a problem with connections to different + # remotes. So the reconnection will only work when we are + # terminating instances left running for the same provider. + # If we are killing an openvpn instance configured for another + # provider, we will get: + # TLS Error: local/remote TLS keys are out of sync + # However, that should be a rare case right now. + self._send_command("signal SIGTERM") + self._close_management_socket(announce=True) + except (Exception, AssertionError) as e: + logger.warning("Problem trying to terminate OpenVPN: %r" + % (e,)) + else: + logger.debug("Could not find the expected openvpn command line.") + + process = self.get_openvpn_process() + if process is None: + logger.debug("Successfully finished already running " + "openvpn process.") + return True + else: + logger.warning("Unable to terminate OpenVPN") + raise OpenVPNAlreadyRunning + + +class VPNProcess(protocol.ProcessProtocol, VPNManager): + """ + A ProcessProtocol class that can be used to spawn a process that will + launch openvpn and connect to its management interface to control it + programmatically. + """ + + def __init__(self, eipconfig, providerconfig, socket_host, socket_port, + signaler, openvpn_verb, remotes): + """ + :param eipconfig: eip configuration object + :type eipconfig: EIPConfig + + :param providerconfig: provider specific configuration + :type providerconfig: ProviderConfig + + :param socket_host: either socket path (unix) or socket IP + :type socket_host: str + + :param socket_port: either string "unix" if it's a unix + socket, or port otherwise + :type socket_port: str + + :param signaler: Signaler object used to receive notifications to the + backend + :type signaler: backend.Signaler + + :param openvpn_verb: the desired level of verbosity in the + openvpn invocation + :type openvpn_verb: int + """ + VPNManager.__init__(self, signaler=signaler) + # leap_assert(not self.isRunning(), "Starting process more than once!") + + self._eipconfig = eipconfig + self._providerconfig = providerconfig + self._socket_host = socket_host + self._socket_port = socket_port + + self._launcher = get_vpn_launcher() + + self._last_state = None + self._last_status = None + self._alive = False + + # XXX use flags, maybe, instead of passing + # the parameter around. + self._openvpn_verb = openvpn_verb + + self._vpn_observer = VPNObserver(signaler) + self.is_restart = False + + self._remotes = remotes + + # processProtocol methods + + def connectionMade(self): + """ + Called when the connection is made. + + .. seeAlso: `http://twistedmatrix.com/documents/13.0.0/api/twisted.internet.protocol.ProcessProtocol.html` # noqa + """ + self._alive = True + self.aborted = False + self.try_to_connect_to_management(max_retries=10) + + def outReceived(self, data): + """ + Called when new data is available on stdout. + + :param data: the data read on stdout + + .. seeAlso: `http://twistedmatrix.com/documents/13.0.0/api/twisted.internet.protocol.ProcessProtocol.html` # noqa + """ + # truncate the newline + line = data[:-1] + logger.info(line) + self._vpn_observer.watch(line) + + def processExited(self, reason): + """ + Called when the child process exits. + + .. seeAlso: `http://twistedmatrix.com/documents/13.0.0/api/twisted.internet.protocol.ProcessProtocol.html` # noqa + """ + exit_code = reason.value.exitCode + if isinstance(exit_code, int): + logger.debug("processExited, status %d" % (exit_code,)) + if self._signaler is not None: + self._signaler.signal( + self._signaler.eip_process_finished, exit_code) + self._alive = False + + def processEnded(self, reason): + """ + Called when the child process exits and all file descriptors associated + with it have been closed. + + .. seeAlso: `http://twistedmatrix.com/documents/13.0.0/api/twisted.internet.protocol.ProcessProtocol.html` # noqa + """ + exit_code = reason.value.exitCode + if isinstance(exit_code, int): + logger.debug("processEnded, status %d" % (exit_code,)) + + # polling + + def pollStatus(self): + """ + Polls connection status. + """ + if self._alive: + self.get_status() + + def pollState(self): + """ + Polls connection state. + """ + if self._alive: + self.get_state() + + # launcher + + def getCommand(self): + """ + Gets the vpn command from the aproppriate launcher. + + Might throw: + VPNLauncherException, + OpenVPNNotFoundException. + + :rtype: list of str + """ + print self._remotes + command = self._launcher.get_vpn_command( + eipconfig=self._eipconfig, + providerconfig=self._providerconfig, + socket_host=self._socket_host, + socket_port=self._socket_port, + openvpn_verb=self._openvpn_verb, + remotes=self._remotes) + + encoding = sys.getfilesystemencoding() + for i, c in enumerate(command): + if not isinstance(c, str): + command[i] = c.encode(encoding) + + logger.debug("Running VPN with command: ") + logger.debug("{0}".format(" ".join(command))) + return command + + def getGateways(self): + """ + Get the gateways from the appropiate launcher. + + :rtype: list + """ + gateways_ports = self._launcher.get_gateways( + self._eipconfig, self._providerconfig) + + # filter out ports since we don't need that info + return [gateway for gateway, port in gateways_ports] + + # shutdown + + def killProcess(self): + """ + Sends the KILL signal to the running process. + """ + try: + self.transport.signalProcess('KILL') + except internet_error.ProcessExitedAlready: + logger.debug('Process Exited Already') |