tahoe-lafs/src/allmydata/util/tor_provider.py
meejah 35810a5692 pull 'basedir' entirely into _Config
Put all config-related methods into _Config; change
code to ask config for paths instead of using basedir;
add some better docstrings
2018-08-25 02:10:44 -06:00

322 lines
14 KiB
Python

# -*- coding: utf-8 -*-
from __future__ import absolute_import, print_function, with_statement
import os
from twisted.internet.defer import inlineCallbacks, returnValue
from twisted.internet.endpoints import clientFromString, TCP4ServerEndpoint
from twisted.internet.error import ConnectionRefusedError, ConnectError
from twisted.application import service
from .observer import OneShotObserverList
from .iputil import allocate_tcp_port
def _import_tor():
# this exists to be overridden by unit tests
try:
from foolscap.connections import tor
return tor
except ImportError: # pragma: no cover
return None
def _import_txtorcon():
try:
import txtorcon
return txtorcon
except ImportError: # pragma: no cover
return None
def data_directory(private_dir):
return os.path.join(private_dir, "tor-statedir")
# different ways we might approach this:
# 1: get an ITorControlProtocol, make a
# txtorcon.EphemeralHiddenService(ports), yield ehs.add_to_tor(tcp), store
# ehs.hostname and ehs.private_key, yield ehs.remove_from_tor(tcp)
def _try_to_connect(reactor, endpoint_desc, stdout, txtorcon):
# yields a TorState, or None
ep = clientFromString(reactor, endpoint_desc)
d = txtorcon.build_tor_connection(ep)
def _failed(f):
# depending upon what's listening at that endpoint, we might get
# various errors. If this list is too short, we might expose an
# exception to the user (causing "tahoe create-node" to fail messily)
# when we're supposed to just try the next potential port instead.
# But I don't want to catch everything, because that may hide actual
# coding errrors.
f.trap(ConnectionRefusedError, # nothing listening on TCP
ConnectError, # missing unix socket, or permission denied
#ValueError,
# connecting to e.g. an HTTP server causes an
# UnhandledException (around a ValueError) when the handshake
# fails to parse, but that's not something we can catch. The
# attempt hangs, so don't do that.
RuntimeError, # authentication failure
)
if stdout:
stdout.write("Unable to reach Tor at '%s': %s\n" %
(endpoint_desc, f.value))
return None
d.addErrback(_failed)
return d
@inlineCallbacks
def _launch_tor(reactor, tor_executable, private_dir, txtorcon):
# TODO: handle default tor-executable
# TODO: it might be a good idea to find exactly which Tor we used,
# and record it's absolute path into tahoe.cfg . This would protect
# us against one Tor being on $PATH at create-node time, but then a
# different Tor being present at node startup. OTOH, maybe we don't
# need to worry about it.
tor_config = txtorcon.TorConfig()
tor_config.DataDirectory = data_directory(private_dir)
# unix-domain control socket
tor_config.ControlPort = "unix:" + os.path.join(private_dir, "tor.control")
tor_control_endpoint_desc = tor_config.ControlPort
tor_config.SOCKSPort = allocate_tcp_port()
tpp = yield txtorcon.launch_tor(
tor_config, reactor,
tor_binary=tor_executable,
# can be useful when debugging; mirror Tor's output to ours
# stdout=sys.stdout,
# stderr=sys.stderr,
)
# now tor is launched and ready to be spoken to
# as a side effect, we've got an ITorControlProtocol ready to go
tor_control_proto = tpp.tor_protocol
# How/when to shut down the new process? for normal usage, the child
# tor will exit when it notices its parent (us) quit. Unit tests will
# mock out txtorcon.launch_tor(), so there will never be a real Tor
# process. So I guess we don't need to track the process.
# If we do want to do anything with it, we can call tpp.quit()
# (because it's a TorProcessProtocol) which returns a Deferred
# that fires when Tor has actually exited.
returnValue((tor_control_endpoint_desc, tor_control_proto))
@inlineCallbacks
def _connect_to_tor(reactor, cli_config, txtorcon):
# we assume tor is already running
ports_to_try = ["unix:/var/run/tor/control",
"tcp:127.0.0.1:9051",
"tcp:127.0.0.1:9151", # TorBrowserBundle
]
if cli_config["tor-control-port"]:
ports_to_try = [cli_config["tor-control-port"]]
for port in ports_to_try:
tor_state = yield _try_to_connect(reactor, port, cli_config.stdout,
txtorcon)
if tor_state:
tor_control_proto = tor_state.protocol
returnValue((port, tor_control_proto)) ; break # helps editor
else:
raise ValueError("unable to reach any default Tor control port")
@inlineCallbacks
def create_config(reactor, cli_config):
txtorcon = _import_txtorcon()
if not txtorcon:
raise ValueError("Cannot create onion without txtorcon. "
"Please 'pip install tahoe-lafs[tor]' to fix this.")
tahoe_config_tor = {} # written into tahoe.cfg:[tor]
private_dir = os.path.abspath(os.path.join(cli_config["basedir"], "private"))
stdout = cli_config.stdout
if cli_config["tor-launch"]:
tahoe_config_tor["launch"] = "true"
tor_executable = cli_config["tor-executable"]
if tor_executable:
tahoe_config_tor["tor.executable"] = tor_executable
print("launching Tor (to allocate .onion address)..", file=stdout)
(_, tor_control_proto) = yield _launch_tor(
reactor, tor_executable, private_dir, txtorcon)
print("Tor launched", file=stdout)
else:
print("connecting to Tor (to allocate .onion address)..", file=stdout)
(port, tor_control_proto) = yield _connect_to_tor(
reactor, cli_config, txtorcon)
print("Tor connection established", file=stdout)
tahoe_config_tor["control.port"] = port
external_port = 3457 # TODO: pick this randomly? there's no contention.
local_port = allocate_tcp_port()
ehs = txtorcon.EphemeralHiddenService(
"%d 127.0.0.1:%d" % (external_port, local_port)
)
print("allocating .onion address (takes ~40s)..", file=stdout)
yield ehs.add_to_tor(tor_control_proto)
print(".onion address allocated", file=stdout)
tor_port = "tcp:%d:interface=127.0.0.1" % local_port
tor_location = "tor:%s:%d" % (ehs.hostname, external_port)
privkey = ehs.private_key
yield ehs.remove_from_tor(tor_control_proto)
# in addition to the "how to launch/connect-to tor" keys above, we also
# record information about the onion service into tahoe.cfg.
# * "local_port" is a server endpont string, which should match
# "tor_port" (which will be added to tahoe.cfg [node] tub.port)
# * "external_port" is the random "public onion port" (integer), which
# (when combined with the .onion address) should match "tor_location"
# (which will be added to tub.location)
# * "private_key_file" points to the on-disk copy of the private key
# material (although we always write it to the same place)
tahoe_config_tor["onion"] = "true"
tahoe_config_tor["onion.local_port"] = str(local_port)
tahoe_config_tor["onion.external_port"] = str(external_port)
assert privkey
tahoe_config_tor["onion.private_key_file"] = os.path.join("private",
"tor_onion.privkey")
privkeyfile = os.path.join(private_dir, "tor_onion.privkey")
with open(privkeyfile, "wb") as f:
f.write(privkey)
# tahoe_config_tor: this is a dictionary of keys/values to add to the
# "[tor]" section of tahoe.cfg, which tells the new node how to launch
# Tor in the right way.
# tor_port: a server endpoint string, it will be added to tub.port=
# tor_location: a foolscap connection hint, "tor:ONION:EXTERNAL_PORT"
# We assume/require that the Node gives us the same data_directory=
# at both create-node and startup time. The data directory is not
# recorded in tahoe.cfg
returnValue((tahoe_config_tor, tor_port, tor_location))
# we can always create a Provider. If foolscap.connections.tor or txtorcon
# are not installed, then get_tor_handler() will return None. If tahoe.cfg
# wants to start an onion service too, then check_onion_config() will throw a
# nice error, and startService will throw an ugly error.
class Provider(service.MultiService):
def __init__(self, config, reactor):
service.MultiService.__init__(self)
self._config = config
self._tor_launched = None
self._onion_ehs = None
self._onion_tor_control_proto = None
self._tor = _import_tor()
self._txtorcon = _import_txtorcon()
self._reactor = reactor
def _get_tor_config(self, *args, **kwargs):
return self._config.get_config("tor", *args, **kwargs)
def get_listener(self):
local_port = int(self._get_tor_config("onion.local_port"))
ep = TCP4ServerEndpoint(self._reactor, local_port, interface="127.0.0.1")
return ep
def get_tor_handler(self):
enabled = self._get_tor_config("enabled", True, boolean=True)
if not enabled:
return None
if not self._tor:
return None
if self._get_tor_config("launch", False, boolean=True):
if not self._txtorcon:
return None
return self._tor.control_endpoint_maker(self._make_control_endpoint,
takes_status=True)
socks_endpoint_desc = self._get_tor_config("socks.port", None)
if socks_endpoint_desc:
socks_ep = clientFromString(self._reactor, socks_endpoint_desc)
return self._tor.socks_endpoint(socks_ep)
controlport = self._get_tor_config("control.port", None)
if controlport:
ep = clientFromString(self._reactor, controlport)
return self._tor.control_endpoint(ep)
return self._tor.default_socks()
@inlineCallbacks
def _make_control_endpoint(self, reactor, update_status):
# this will only be called when tahoe.cfg has "[tor] launch = true"
update_status("launching Tor")
with self._tor.add_context(update_status, "launching Tor"):
(endpoint_desc, _) = yield self._get_launched_tor(reactor)
tor_control_endpoint = clientFromString(reactor, endpoint_desc)
returnValue(tor_control_endpoint)
def _get_launched_tor(self, reactor):
# this fires with a tuple of (control_endpoint, tor_protocol)
if not self._tor_launched:
self._tor_launched = OneShotObserverList()
private_dir = self._config.get_config_path("private")
tor_binary = self._get_tor_config("tor.executable", None)
d = _launch_tor(reactor, tor_binary, private_dir, self._txtorcon)
d.addBoth(self._tor_launched.fire)
return self._tor_launched.when_fired()
def check_onion_config(self):
if self._get_tor_config("onion", False, boolean=True):
if not self._txtorcon:
raise ValueError("Cannot create onion without txtorcon. "
"Please 'pip install tahoe-lafs[tor]' to fix.")
# to start an onion server, we either need a Tor control port, or
# we need to launch tor
launch = self._get_tor_config("launch", False, boolean=True)
controlport = self._get_tor_config("control.port", None)
if not launch and not controlport:
raise ValueError("[tor] onion = true, but we have neither "
"launch=true nor control.port=")
# check that all the expected onion-specific keys are present
def require(name):
if not self._get_tor_config("onion.%s" % name, None):
raise ValueError("[tor] onion = true,"
" but onion.%s= is missing" % name)
require("local_port")
require("external_port")
require("private_key_file")
@inlineCallbacks
def _start_onion(self, reactor):
# launch tor, if necessary
if self._get_tor_config("launch", False, boolean=True):
(_, tor_control_proto) = yield self._get_launched_tor(reactor)
else:
controlport = self._get_tor_config("control.port", None)
tcep = clientFromString(reactor, controlport)
tor_state = yield self._txtorcon.build_tor_connection(tcep)
tor_control_proto = tor_state.protocol
local_port = int(self._get_tor_config("onion.local_port"))
external_port = int(self._get_tor_config("onion.external_port"))
fn = self._get_tor_config("onion.private_key_file")
privkeyfile = self._config.get_config_path(fn)
with open(privkeyfile, "rb") as f:
privkey = f.read()
ehs = self._txtorcon.EphemeralHiddenService(
"%d 127.0.0.1:%d" % (external_port, local_port), privkey)
yield ehs.add_to_tor(tor_control_proto)
self._onion_ehs = ehs
self._onion_tor_control_proto = tor_control_proto
def startService(self):
service.MultiService.startService(self)
# if we need to start an onion service, now is the time
if self._get_tor_config("onion", False, boolean=True):
return self._start_onion(self._reactor) # so tests can synchronize
@inlineCallbacks
def stopService(self):
if self._onion_ehs and self._onion_tor_control_proto:
yield self._onion_ehs.remove_from_tor(self._onion_tor_control_proto)
# TODO: can we also stop tor?
yield service.MultiService.stopService(self)