ntunnel/ntunnel.py

from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import x448
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.primitives.kdf.hkdf import HKDF
from cryptography.hazmat.primitives.serialization import load_pem_private_key
from noise.connection import NoiseConnection, Keypair

#import tracemalloc; tracemalloc.start(100)

import argparse
import asyncio
import base64
import os.path
import shutil
import socket
import sys
import tempfile
import time
import threading
import unittest

_backend = default_backend()

def loadprivkey(fname):
	with open(fname, encoding='ascii') as fp:
		data = fp.read().encode('ascii')
		key = load_pem_private_key(data, password=None, backend=default_backend())

	return key

def loadprivkeyraw(fname):
	key = loadprivkey(fname)

	enc = serialization.Encoding.Raw
	privformat = serialization.PrivateFormat.Raw
	encalgo = serialization.NoEncryption()

	return key.private_bytes(encoding=enc, format=privformat, encryption_algorithm=encalgo)

def loadpubkeyraw(fname):
	with open(fname, encoding='ascii') as fp:
		lines = fp.readlines()

		# XXX
		#self.assertEqual(len(lines), 1)

		keytype, keyvalue = lines[0].split()

		if keytype != 'ntun-x448':
			raise RuntimeError

		return base64.urlsafe_b64decode(keyvalue)

def genkeypair():
	'''Generates a keypair, and returns a tuple of (public, private).
	They are encoded as raw bytes, and sutible for use w/ Noise.'''

	key = x448.X448PrivateKey.generate()

	enc = serialization.Encoding.Raw
	pubformat = serialization.PublicFormat.Raw
	privformat = serialization.PrivateFormat.Raw
	encalgo = serialization.NoEncryption()

	pub = key.public_key().public_bytes(encoding=enc, format=pubformat)
	priv = key.private_bytes(encoding=enc, format=privformat, encryption_algorithm=encalgo)

	return pub, priv

def _makefut(obj):
	loop = asyncio.get_running_loop()
	fut = loop.create_future()
	fut.set_result(obj)

	return fut

def _makeunix(path):
	'''Make a properly formed unix path socket string.'''

	return 'unix:%s' % path

# Make sure any additions are reflected by tests in test_parsesockstr
_allowedparameters = {
	'unix': {
		'path': str,
	},
	'tcp': {
		'host': str,
		'port': int,
	},
}

def parsesockstr(sockstr):
	'''Parse a socket string to its parts.

	The format of sockstr is: 'proto:param=value[,param2=value2]'.
	If the proto has a default parameter, the value can be used
	directly, like: 'proto:value'.  This is only allowed when the
	value can unambiguously be determined not to be a param.  If
	there needs to be an equals '=', then you MUST use the extended
	version.

	The characters that define 'param' must be all lower case ascii
	characters and may contain an underscore.  The first character
	must not be an underscore.

	Supported protocols:
		unix:
			Default parameter is path.
			The path parameter specifies the path to the
			unix domain socket.  The path MUST start w/ a
			slash if it is used as a default parameter.

		tcp:
			Default parameter is host[:port].
			The host parameter specifies the host, and the
			port parameter specifies the port of the
			connection.
	'''

	proto, rem = sockstr.split(':', 1)

	if '=' not in rem:
		if proto == 'unix' and rem[0] != '/':
			raise ValueError('bare path MUST start w/ a slash (/).')

		if proto == 'unix':
			args = { 'path': rem }
	else:
		args = dict(i.split('=', 1) for i in rem.split(','))

	try:
		allowed = _allowedparameters[proto]
	except KeyError:
		raise ValueError('unsupported proto: %s' % repr(proto))

	extrakeys = args.keys() - allowed.keys()
	if extrakeys:
		raise ValueError('keys for proto %s not allowed: %s' % (repr(proto), extrakeys))

	for i in args:
		args[i] = allowed[i](args[i])

	return proto, args

async def connectsockstr(sockstr):
	'''Wrapper for asyncio.open_*_connection.'''

	proto, args = parsesockstr(sockstr)

	if proto == 'unix':
		fun = asyncio.open_unix_connection
	elif proto == 'tcp':
		fun = asyncio.open_connection

	reader, writer = await fun(**args)

	return reader, writer

async def listensockstr(sockstr, cb):
	'''Wrapper for asyncio.start_x_server.

	For the format of sockstr, please see parsesockstr.

	The cb parameter is passed to asyncio's start_server or related
	calls.  Per those docs, the cb parameter is calls or scheduled
	as a task when a client establishes a connection.  It is called
	with two arguments, the reader and writer streams.  For more
	information, see: https://docs.python.org/3/library/asyncio-stream.html#asyncio.start_server

	'''

	proto, args = parsesockstr(sockstr)

	if proto == 'unix':
		fun = asyncio.start_unix_server
	elif proto == 'tcp':
		fun = asyncio.start_server

	return await fun(cb, **args)

# !!python makemessagelengths.py
_handshakelens = \
[72, 72, 88]

def _genciphfun(hash, ad):
	hkdf = HKDF(algorithm=hashes.SHA256(), length=32,
	    salt=b'asdoifjsldkjdsf', info=ad, backend=_backend)

	key = hkdf.derive(hash)
	cipher = Cipher(algorithms.AES(key), modes.ECB(),
	    backend=_backend)
	enctor = cipher.encryptor()

	def encfun(data):
		# Returns the two bytes for length
		val = len(data)
		encbytes = enctor.update(data[:16])
		mask = int.from_bytes(encbytes[:2], byteorder='big') & 0xff

		return (val ^ mask).to_bytes(length=2, byteorder='big')

	def decfun(data):
		# takes off the data and returns the total
		# length
		val = int.from_bytes(data[:2], byteorder='big')
		encbytes = enctor.update(data[2:2 + 16])
		mask = int.from_bytes(encbytes[:2], byteorder='big') & 0xff

		return val ^ mask

	return encfun, decfun

async def NoiseForwarder(mode, encrdrwrr, ptpairfun, priv_key, pub_key=None):
	'''A function that forwards data between the plain text pair of
	streams to the encrypted session.

	The mode paramater must be one of 'init' or 'resp' for initiator
	and responder.

	The encrdrwrr is an await object that will return a tunle of the
	reader and writer streams for the encrypted side of the
	connection.

	The ptpairfun parameter is a function that will be passed the
	public key bytes for the remote client.  This can be used to
	both validate that the correct client is connecting, and to
	pass back the correct plain text reader/writer objects that
	match the provided static key.  The function must be an async
	function.

	In the case of the initiator, pub_key must be provided and will
	be used to authenticate the responder side of the connection.

	The priv_key parameter is used to authenticate this side of the
	session.

	Both priv_key and pub_key parameters must be 56 bytes.  For example,
	the pair that is returned by genkeypair.
	'''

	# Send a protocol version so that in the future we can change how
	# we interface, and possibly be able to send control messages,
	# allow the client to pass some misc data to the callback, or to
	# allow a reverse tunnel, were the client talks to the server,
	# and waits for the server to "connect" to the client w/ a
	# connection, e.g. reverse tunnel out behind a nat to allow
	# incoming connections.
	protocol_version = 0

	rdr, wrr = await encrdrwrr

	proto = NoiseConnection.from_name(b'Noise_XK_448_ChaChaPoly_SHA256')

	proto.set_keypair_from_private_bytes(Keypair.STATIC, priv_key)
	if pub_key is not None:
		proto.set_keypair_from_public_bytes(Keypair.REMOTE_STATIC,
		    pub_key)

	if mode == 'resp':
		proto.set_as_responder()

		proto.start_handshake()

		proto.read_message(await rdr.readexactly(_handshakelens[0]))

		wrr.write(proto.write_message())

		proto.read_message(await rdr.readexactly(_handshakelens[2]))
	elif mode == 'init':
		proto.set_as_initiator()

		proto.start_handshake()

		wrr.write(proto.write_message())

		proto.read_message(await rdr.readexactly(_handshakelens[1]))

		wrr.write(proto.write_message())

	if not proto.handshake_finished:	# pragma: no cover
		raise RuntimeError('failed to finish handshake')

	try:
		reader, writer = await ptpairfun(getattr(proto.get_keypair(
		    Keypair.REMOTE_STATIC), 'public_bytes', None))
	except:
		wrr.close()
		raise

	# generate the keys for lengths
	# XXX - get_handshake_hash is probably not the best option, but
	# this is only to obscure lengths, it is not required to be secure
	# as the underlying NoiseProtocol securely validates everything.
	# It is marginally useful as writing patterns likely expose the
	# true length.  Adding padding could marginally help w/ this.
	if mode == 'resp':
		_, declenfun = _genciphfun(proto.get_handshake_hash(), b'toresp')
		enclenfun, _ = _genciphfun(proto.get_handshake_hash(), b'toinit')
	elif mode == 'init':
		enclenfun, _ = _genciphfun(proto.get_handshake_hash(), b'toresp')
		_, declenfun = _genciphfun(proto.get_handshake_hash(), b'toinit')

	# protocol negotiation

	# send first, then wait for the response
	pvmsg = protocol_version.to_bytes(1, byteorder='big')
	encmsg = proto.encrypt(pvmsg)
	wrr.write(enclenfun(encmsg))
	wrr.write(encmsg)

	# get the protocol version
	msg = await rdr.readexactly(2 + 16)
	tlen = declenfun(msg)
	rmsg = await rdr.readexactly(tlen - 16)
	tmsg = msg[2:] + rmsg
	rpv = proto.decrypt(tmsg)

	async def decses():
		try:
			while True:
				try:
					msg = await rdr.readexactly(2 + 16)
				except asyncio.streams.IncompleteReadError:
					if rdr.at_eof():
						return 'dec'

				tlen = declenfun(msg)
				rmsg = await rdr.readexactly(tlen - 16)
				tmsg = msg[2:] + rmsg
				writer.write(proto.decrypt(tmsg))
				await writer.drain()
		#except:
		#	import traceback
		#	traceback.print_exc()
		#	raise
		finally:
			try:
				writer.write_eof()
			except OSError as e:
				if e.errno != 57:
					raise

	async def encses():
		try:
			while True:
				# largest message
				ptmsg = await reader.read(65535 - 16)
				if not ptmsg:
					# eof
					return 'enc'

				encmsg = proto.encrypt(ptmsg)
				wrr.write(enclenfun(encmsg))
				wrr.write(encmsg)
				await wrr.drain()
		#except:
		#	import traceback
		#	traceback.print_exc()
		#	raise
		finally:
			wrr.write_eof()

	res = await asyncio.gather(decses(), encses())

	await wrr.drain()	# not sure if needed
	wrr.close()

	await writer.drain()	# not sure if needed
	writer.close()

	return res

# https://stackoverflow.com/questions/23033939/how-to-test-python-3-4-asyncio-code
# Slightly modified to timeout and to print trace back when canceled.
# This makes it easier to figure out what "froze".
def async_test(f):
	def wrapper(*args, **kwargs):
		async def tbcapture():
			try:
				return await f(*args, **kwargs)
			except asyncio.CancelledError as e:
				# if we are going to be cancelled, print out a tb
				import traceback
				traceback.print_exc()
				raise

		loop = asyncio.get_event_loop()

		# timeout after 4 seconds
		loop.run_until_complete(asyncio.wait_for(tbcapture(), 4))
	return wrapper

class Tests_misc(unittest.TestCase):
	def setUp(self):
		# setup temporary directory
		d = os.path.realpath(tempfile.mkdtemp())
		self.basetempdir = d
		self.tempdir = os.path.join(d, 'subdir')
		os.mkdir(self.tempdir)

		os.chdir(self.tempdir)

	def tearDown(self):
		#print('td:', time.time())
		shutil.rmtree(self.basetempdir)
		self.tempdir = None

	def test_parsesockstr_bad(self):
		badstrs = [
			'unix:ff',
			'randomnocolon',
			'unix:somethingelse=bogus',
			'tcp:port=bogus',
		]

		for i in badstrs:
			with self.assertRaises(ValueError,
			    msg='Should have failed processing: %s' % repr(i)):
				parsesockstr(i)

	def test_parsesockstr(self):
		results = {
			# Not all of these are valid when passed to a *sockstr
			# function
			'unix:/apath': ('unix', { 'path': '/apath' }),
			'unix:path=apath': ('unix', { 'path': 'apath' }),
			'tcp:host=apath': ('tcp', { 'host': 'apath' }),
			'tcp:host=apath,port=5': ('tcp', { 'host': 'apath',
			    'port': 5 }),
		}

		for s, r in results.items():
			self.assertEqual(parsesockstr(s), r)

	@async_test
	async def test_listensockstr_bad(self):
		with self.assertRaises(ValueError):
			ls = await listensockstr('bogus:some=arg', None)

		with self.assertRaises(ValueError):
			ls = await connectsockstr('bogus:some=arg')

	@async_test
	async def test_listenconnectsockstr(self):
		msgsent = b'this is a test message'
		msgrcv = b'testing message for receive'

		# That when a connection is received and receives and sends
		async def servconfhandle(rdr, wrr):
			msg = await rdr.readexactly(len(msgsent))
			self.assertEqual(msg, msgsent)

			#print(repr(wrr.get_extra_info('sockname')))
			wrr.write(msgrcv)
			await wrr.drain()

			wrr.close()

			return True

		# Test listensockstr
		for sstr, confun in [
		    ('unix:path=ff', lambda: asyncio.open_unix_connection(path='ff')),
		    ('tcp:port=9384', lambda: asyncio.open_connection(port=9384))
		]:
			# that listensockstr will bind to the correct path, can call cb
			ls = await listensockstr(sstr, servconfhandle)

			# that we open a connection to the path
			rdr, wrr = await confun()

			# and send a message
			wrr.write(msgsent)

			# and receive the message
			rcv = await asyncio.wait_for(rdr.readexactly(len(msgrcv)), .5)
			self.assertEqual(rcv, msgrcv)

			wrr.close()

			# Now test that connectsockstr works similarly.
			rdr, wrr = await connectsockstr(sstr)

			# and send a message
			wrr.write(msgsent)

			# and receive the message
			rcv = await asyncio.wait_for(rdr.readexactly(len(msgrcv)), .5)
			self.assertEqual(rcv, msgrcv)

			wrr.close()

			ls.close()
			await ls.wait_closed()

	def test_genciphfun(self):
		enc, dec = _genciphfun(b'0' * 32, b'foobar')

		msg = b'this is a bunch of data'

		tb = enc(msg)

		self.assertEqual(len(msg), dec(tb + msg))

		for i in [ 20, 1384, 64000, 23839, 65535 ]:
			msg = os.urandom(i)
			self.assertEqual(len(msg), dec(enc(msg) + msg))

def cmd_client(args):
	privkey = loadprivkeyraw(args.clientkey)
	pubkey = loadpubkeyraw(args.servkey)
	async def runnf(rdr, wrr):
		encpair = asyncio.create_task(connectsockstr(args.clienttarget))

		a = await NoiseForwarder('init',
		    encpair, lambda x: _makefut((rdr, wrr)),
		    priv_key=privkey, pub_key=pubkey)

	# Setup client listener
	ssock = listensockstr(args.clientlisten, runnf)

	loop = asyncio.get_event_loop()

	obj = loop.run_until_complete(ssock)

	loop.run_until_complete(obj.serve_forever())

def cmd_server(args):
	privkey = loadprivkeyraw(args.servkey)
	pubkeys = [ loadpubkeyraw(x) for x in args.clientkey ]

	async def runnf(rdr, wrr):
		async def checkclientfun(clientkey):
			if clientkey not in pubkeys:
				raise RuntimeError('invalid key provided')

			return await connectsockstr(args.servtarget)

		a = await NoiseForwarder('resp', _makefut((rdr, wrr)),
		    checkclientfun, priv_key=privkey)

	# Setup server listener
	ssock = listensockstr(args.servlisten, runnf)

	loop = asyncio.get_event_loop()

	obj = loop.run_until_complete(ssock)

	loop.run_until_complete(obj.serve_forever())

def cmd_genkey(args):
	keypair = genkeypair()

	key = x448.X448PrivateKey.generate()

	# public key part
	enc = serialization.Encoding.Raw
	pubformat = serialization.PublicFormat.Raw
	pub = key.public_key().public_bytes(encoding=enc, format=pubformat)

	try:
		fname = args.fname + '.pub'
		with open(fname, 'x', encoding='ascii') as fp:
			print('ntun-x448', base64.urlsafe_b64encode(pub).decode('ascii'), file=fp)
	except FileExistsError:
		print('failed to create %s, file exists.' % fname, file=sys.stderr)
		sys.exit(2)

	enc = serialization.Encoding.PEM
	format = serialization.PrivateFormat.PKCS8
	encalgo = serialization.NoEncryption()
	with open(args.fname, 'x', encoding='ascii') as fp:
		fp.write(key.private_bytes(encoding=enc, format=format, encryption_algorithm=encalgo).decode('ascii'))

def main():
	parser = argparse.ArgumentParser()

	subparsers = parser.add_subparsers(title='subcommands', description='valid subcommands', help='additional help')

	parser_gk = subparsers.add_parser('genkey', help='generate keys')
	parser_gk.add_argument('fname', type=str, help='file name for the key')
	parser_gk.set_defaults(func=cmd_genkey)

	parser_serv = subparsers.add_parser('server', help='run a server')
	parser_serv.add_argument('--clientkey', '-c', action='append', type=str, help='file of authorized client keys, or a .pub file')
	parser_serv.add_argument('servkey', type=str, help='file name for the server key')
	parser_serv.add_argument('servlisten', type=str, help='Connection that the server listens on')
	parser_serv.add_argument('servtarget', type=str, help='Connection that the server connects to')
	parser_serv.set_defaults(func=cmd_server)

	parser_client = subparsers.add_parser('client', help='run a client')
	parser_client.add_argument('clientkey', type=str, help='file name for the client private key')
	parser_client.add_argument('servkey', type=str, help='file name for the server public key')
	parser_client.add_argument('clientlisten', type=str, help='Connection that the client listens on')
	parser_client.add_argument('clienttarget', type=str, help='Connection that the client connects to')
	parser_client.set_defaults(func=cmd_client)

	args = parser.parse_args()

	try:
		fun = args.func
	except AttributeError:
		parser.print_usage()
		sys.exit(5)

	fun(args)

if __name__ == '__main__':	# pragma: no cover
	main()

def _asyncsockpair():
	'''Create a pair of sockets that are bound to each other.
	The function will return a tuple of two coroutine's, that
	each, when await'ed upon, will return the reader/writer pair.'''

	socka, sockb = socket.socketpair()

	return asyncio.open_connection(sock=socka), \
	    asyncio.open_connection(sock=sockb)

async def _awaitfile(fname):
	while not os.path.exists(fname):
		await asyncio.sleep(.01)

	return True

class TestMain(unittest.TestCase):
	def setUp(self):
		# setup temporary directory
		d = os.path.realpath(tempfile.mkdtemp())
		self.basetempdir = d
		self.tempdir = os.path.join(d, 'subdir')
		os.mkdir(self.tempdir)

		# Generate key pairs
		self.server_key_pair = genkeypair()
		self.client_key_pair = genkeypair()

		os.chdir(self.tempdir)

	def tearDown(self):
		#print('td:', time.time())
		shutil.rmtree(self.basetempdir)
		self.tempdir = None

	@async_test
	async def test_noargs(self):
		proc = await self.run_with_args()

		await proc.wait()

		# XXX - not checking error message

		# And that it exited w/ the correct code
		self.assertEqual(proc.returncode, 5)

	def run_with_args(self, *args, pipes=True):
		kwargs = {}
		if pipes:
			kwargs.update(dict(
			    stdout=asyncio.subprocess.PIPE,
			    stderr=asyncio.subprocess.PIPE))
		return asyncio.create_subprocess_exec(sys.executable,
		    # XXX - figure out how to add coverage data on these runs
		    #'-m', 'coverage', 'run', '-p',
		    __file__, *args, **kwargs)

	async def genkey(self, name):
		proc = await self.run_with_args('genkey', name, pipes=False)

		await proc.wait()

		self.assertEqual(proc.returncode, 0)

	@async_test
	async def test_loadpubkey(self):
		keypath = os.path.join(self.tempdir, 'loadpubkeytest')
		await self.genkey(keypath)

		privkey = loadprivkey(keypath)

		enc = serialization.Encoding.Raw
		pubformat = serialization.PublicFormat.Raw

		pubkeybytes = privkey.public_key().public_bytes(encoding=enc, format=pubformat)

		pubkey = loadpubkeyraw(keypath + '.pub')

		self.assertEqual(pubkeybytes, pubkey)

		privrawkey = loadprivkeyraw(keypath)

		enc = serialization.Encoding.Raw
		privformat = serialization.PrivateFormat.Raw
		encalgo = serialization.NoEncryption()

		rprivrawkey = privkey.private_bytes(encoding=enc, format=privformat, encryption_algorithm=encalgo)

		self.assertEqual(rprivrawkey, privrawkey)

	@async_test
	async def test_clientkeymismatch(self):
		# make sure that if there's a client key mismatch, we
		# don't connect

		# Generate necessar keys
		servkeypath = os.path.join(self.tempdir, 'server_key')
		await self.genkey(servkeypath)
		clientkeypath = os.path.join(self.tempdir, 'client_key')
		await self.genkey(clientkeypath)
		badclientkeypath = os.path.join(self.tempdir, 'badclient_key')
		await self.genkey(badclientkeypath)

		# forwards connectsion to this socket (created by client)
		ptclientpath = os.path.join(self.tempdir, 'incclient.sock')
		ptclientstr = _makeunix(ptclientpath)

		# this is the socket server listen to
		incservpath = os.path.join(self.tempdir, 'incserv.sock')
		incservstr = _makeunix(incservpath)

		# to this socket, opened by server
		servtargpath = os.path.join(self.tempdir, 'servtarget.sock')
		servtargstr = _makeunix(servtargpath)

		# Setup server target listener
		ptsockevent = asyncio.Event()

		# Bind to pt listener
		lsock = await listensockstr(servtargstr, None)

		# Startup the server
		server = await self.run_with_args('server',
		    '-c', clientkeypath + '.pub',
		    servkeypath, incservstr, servtargstr)

		# Startup the client with the "bad" key
		client = await self.run_with_args('client',
		    badclientkeypath, servkeypath + '.pub', ptclientstr, incservstr)

		# wait for server target to be created
		await _awaitfile(servtargpath)

		# wait for server to start
		await _awaitfile(incservpath)

		# wait for client to start
		await _awaitfile(ptclientpath)

		# Connect to the client
		reader, writer = await connectsockstr(ptclientstr)

		# XXX - this might not be the best test.
		with self.assertRaises(asyncio.futures.TimeoutError):
			# make sure that we don't get the conenction
			await asyncio.wait_for(ptsockevent.wait(), .5)

		writer.close()

		# Make sure that when the server is terminated
		server.terminate()

		# that it's stderr
		stdout, stderr = await server.communicate()
		#print('s:', repr((stdout, stderr)))

		# doesn't have an exceptions never retrieved
		# even the example echo server has this same leak
		#self.assertNotIn(b'Task exception was never retrieved', stderr)

		lsock.close()
		await lsock.wait_closed()

	@async_test
	async def test_end2end(self):
		# Generate necessar keys
		servkeypath = os.path.join(self.tempdir, 'server_key')
		await self.genkey(servkeypath)
		clientkeypath = os.path.join(self.tempdir, 'client_key')
		await self.genkey(clientkeypath)

		# forwards connectsion to this socket (created by client)
		ptclientpath = os.path.join(self.tempdir, 'incclient.sock')
		ptclientstr = _makeunix(ptclientpath)

		# this is the socket server listen to
		incservpath = os.path.join(self.tempdir, 'incserv.sock')
		incservstr = _makeunix(incservpath)

		# to this socket, opened by server
		servtargpath = os.path.join(self.tempdir, 'servtarget.sock')
		servtargstr = _makeunix(servtargpath)

		# Setup server target listener
		ptsock = []
		ptsockevent = asyncio.Event()
		def ptsockaccept(reader, writer, ptsock=ptsock):
			ptsock.append((reader, writer))
			ptsockevent.set()

		# Bind to pt listener
		lsock = await listensockstr(servtargstr, ptsockaccept)

		# Startup the server
		server = await self.run_with_args('server',
		    '-c', clientkeypath + '.pub',
		    servkeypath, incservstr, servtargstr,
		    pipes=False)

		# Startup the client
		client = await self.run_with_args('client',
		    clientkeypath, servkeypath + '.pub', ptclientstr, incservstr,
		    pipes=False)

		# wait for server target to be created
		await _awaitfile(servtargpath)

		# wait for server to start
		await _awaitfile(incservpath)

		# wait for client to start
		await _awaitfile(ptclientpath)

		# Connect to the client
		reader, writer = await connectsockstr(ptclientstr)

		# send a message
		ptmsg = b'this is a message for testing'
		writer.write(ptmsg)

		# make sure that we got the conenction
		await ptsockevent.wait()

		# get the connection
		endrdr, endwrr = ptsock[0]

		# make sure we can read back what we sent
		self.assertEqual(ptmsg, await endrdr.readexactly(len(ptmsg)))

		# test some additional messages
		for i in [ 129, 1287, 28792, 129872 ]:
			# in on direction
			msg = os.urandom(i)
			writer.write(msg)
			self.assertEqual(msg, await endrdr.readexactly(len(msg)))

			# and the other
			endwrr.write(msg)
			self.assertEqual(msg, await reader.readexactly(len(msg)))

		writer.close()
		endwrr.close()

		lsock.close()
		await lsock.wait_closed()

	@async_test
	async def test_genkey(self):
		# that it can generate a key
		proc = await self.run_with_args('genkey', 'somefile')

		await proc.wait()

		#print(await proc.communicate())

		self.assertEqual(proc.returncode, 0)

		with open('somefile.pub', encoding='ascii') as fp:
			lines = fp.readlines()
			self.assertEqual(len(lines), 1)

			keytype, keyvalue = lines[0].split()

			self.assertEqual(keytype, 'ntun-x448')
			key = x448.X448PublicKey.from_public_bytes(base64.urlsafe_b64decode(keyvalue))

		key = loadprivkey('somefile')
		self.assertIsInstance(key, x448.X448PrivateKey)

		# that a second call fails
		proc = await self.run_with_args('genkey', 'somefile')

		await proc.wait()

		stdoutdata, stderrdata = await proc.communicate()

		self.assertFalse(stdoutdata)
		self.assertEqual(b'failed to create somefile.pub, file exists.\n', stderrdata)

		# And that it exited w/ the correct code
		self.assertEqual(proc.returncode, 2)

class TestNoiseFowarder(unittest.TestCase):
	def setUp(self):
		# setup temporary directory
		d = os.path.realpath(tempfile.mkdtemp())
		self.basetempdir = d
		self.tempdir = os.path.join(d, 'subdir')
		os.mkdir(self.tempdir)

		# Generate key pairs
		self.server_key_pair = genkeypair()
		self.client_key_pair = genkeypair()

	def tearDown(self):
		shutil.rmtree(self.basetempdir)
		self.tempdir = None

	@async_test
	async def test_clientkeymissmatch(self):
		# generate a key that is incorrect
		wrongclient_key_pair = genkeypair()

		# the secure socket
		clssockapair, clssockbpair = _asyncsockpair()
		reader, writer = await clssockapair

		async def wrongkey(v):
			raise ValueError('no key matches')

		# create the server
		servnf = asyncio.create_task(NoiseForwarder('resp',
		    clssockbpair, wrongkey,
		    priv_key=self.server_key_pair[1]))

		# Create client
		proto = NoiseConnection.from_name(
		    b'Noise_XK_448_ChaChaPoly_SHA256')
		proto.set_as_initiator()

		# Setup wrong client key
		proto.set_keypair_from_private_bytes(Keypair.STATIC,
		    wrongclient_key_pair[1])

		# but the correct server key
		proto.set_keypair_from_public_bytes(Keypair.REMOTE_STATIC,
		    self.server_key_pair[0])

		proto.start_handshake()

		# Send first message
		message = proto.write_message()
		self.assertEqual(len(message), _handshakelens[0])
		writer.write(message)

		# Get response
		respmsg = await reader.readexactly(_handshakelens[1])
		proto.read_message(respmsg)

		# Send final reply
		message = proto.write_message()
		writer.write(message)

		# Make sure handshake has completed
		self.assertTrue(proto.handshake_finished)

		with self.assertRaises(ValueError):
			await servnf

		writer.close()

	@async_test
	async def test_server(self):
		# Test is plumbed:
		#   (reader, writer) -> servsock ->
		#     (rdr, wrr) NoiseForward (reader, writer) ->
		#     servptsock -> (ptsock[0], ptsock[1])
		# Path that the server will sit on
		servsockpath = os.path.join(self.tempdir, 'servsock')
		servarg = _makeunix(servsockpath)

		# Path that the server will send pt data to
		servptpath = os.path.join(self.tempdir, 'servptsock')

		# Setup pt target listener
		pttarg = _makeunix(servptpath)
		ptsock = []
		ptsockevent = asyncio.Event()
		def ptsockaccept(reader, writer, ptsock=ptsock):
			ptsock.append((reader, writer))
			ptsockevent.set()

		# Bind to pt listener
		lsock = await listensockstr(pttarg, ptsockaccept)

		nfs = []
		event = asyncio.Event()

		async def runnf(rdr, wrr):
			ptpairfun = asyncio.create_task(connectsockstr(pttarg))

			a = await NoiseForwarder('resp',
			    _makefut((rdr, wrr)), lambda x: ptpairfun,
			    priv_key=self.server_key_pair[1])

			nfs.append(a)
			event.set()

		# Setup server listener
		ssock = await listensockstr(servarg, runnf)

		# Connect to server
		reader, writer = await connectsockstr(servarg)

		# Create client
		proto = NoiseConnection.from_name(b'Noise_XK_448_ChaChaPoly_SHA256')
		proto.set_as_initiator()

		# Setup required keys
		proto.set_keypair_from_private_bytes(Keypair.STATIC,
		    self.client_key_pair[1])
		proto.set_keypair_from_public_bytes(Keypair.REMOTE_STATIC,
		    self.server_key_pair[0])

		proto.start_handshake()

		# Send first message
		message = proto.write_message()
		self.assertEqual(len(message), _handshakelens[0])
		writer.write(message)

		# Get response
		respmsg = await reader.readexactly(_handshakelens[1])
		proto.read_message(respmsg)

		# Send final reply
		message = proto.write_message()
		writer.write(message)

		# Make sure handshake has completed
		self.assertTrue(proto.handshake_finished)

		# generate the keys for lengths
		enclenfun, _ = _genciphfun(proto.get_handshake_hash(),
		    b'toresp')
		_, declenfun = _genciphfun(proto.get_handshake_hash(),
		    b'toinit')

		pversion = 0
		# Send the protocol version string first
		encmsg = proto.encrypt(pversion.to_bytes(1, byteorder='big'))
		writer.write(enclenfun(encmsg))
		writer.write(encmsg)

		# Read the peer's protocol version

		# find out how much we need to read
		encmsg = await reader.readexactly(2 + 16)
		tlen = declenfun(encmsg)

		# read the rest of the message
		rencmsg = await reader.readexactly(tlen - 16)
		tmsg = encmsg[2:] + rencmsg
		rptmsg = proto.decrypt(tmsg)

		self.assertEqual(int.from_bytes(rptmsg, byteorder='big'), pversion)

		# write a test message
		ptmsg = b'this is a test message that should be a little in length'
		encmsg = proto.encrypt(ptmsg)
		writer.write(enclenfun(encmsg))
		writer.write(encmsg)

		# wait for the connection to arrive
		await ptsockevent.wait()

		ptreader, ptwriter = ptsock[0]
		# read the test message
		rptmsg = await ptreader.readexactly(len(ptmsg))

		self.assertEqual(rptmsg, ptmsg)

		# write a different message
		ptmsg = os.urandom(2843)
		encmsg = proto.encrypt(ptmsg)
		writer.write(enclenfun(encmsg))
		writer.write(encmsg)

		# read the test message
		rptmsg = await ptreader.readexactly(len(ptmsg))

		self.assertEqual(rptmsg, ptmsg)

		# now try the other way
		ptmsg = os.urandom(912)
		ptwriter.write(ptmsg)

		# find out how much we need to read
		encmsg = await reader.readexactly(2 + 16)
		tlen = declenfun(encmsg)

		# read the rest of the message
		rencmsg = await reader.readexactly(tlen - 16)
		tmsg = encmsg[2:] + rencmsg
		rptmsg = proto.decrypt(tmsg)

		self.assertEqual(rptmsg, ptmsg)

		# shut down sending
		writer.write_eof()

		# so pt reader should be shut down
		self.assertEqual(b'', await ptreader.read(1))
		self.assertTrue(ptreader.at_eof())

		# shut down pt
		ptwriter.write_eof()

		# make sure the enc reader is eof
		self.assertEqual(b'', await reader.read(1))
		self.assertTrue(reader.at_eof())

		await event.wait()

		self.assertEqual(nfs[0], [ 'dec', 'enc' ])

		writer.close()
		ptwriter.close()

		lsock.close()
		ssock.close()
		await lsock.wait_closed()
		await ssock.wait_closed()

	@async_test
	async def test_serverclient(self):
		# plumbing:
		#
		#   ptca -> ptcb NF client clsa -> clsb NF server ptsa -> ptsb
		#

		ptcsockapair, ptcsockbpair = _asyncsockpair()
		ptcareader, ptcawriter = await ptcsockapair
		#ptcsockbpair passed directly
		clssockapair, clssockbpair = _asyncsockpair()
		#both passed directly
		ptssockapair, ptssockbpair = _asyncsockpair()
		#ptssockapair passed directly
		ptsbreader, ptsbwriter = await ptssockbpair

		async def validateclientkey(pubkey):
			self.assertEqual(pubkey, self.client_key_pair[0])

			return await ptssockapair

		clientnf = asyncio.create_task(NoiseForwarder('init',
		    clssockapair, lambda x: ptcsockbpair,
		    priv_key=self.client_key_pair[1],
		    pub_key=self.server_key_pair[0]))
		servnf = asyncio.create_task(NoiseForwarder('resp',
		    clssockbpair, validateclientkey,
		    priv_key=self.server_key_pair[1]))

		# send a message
		msga = os.urandom(183)
		ptcawriter.write(msga)

		# make sure we get the same message
		self.assertEqual(msga, await ptsbreader.readexactly(len(msga)))

		# send a second message
		msga = os.urandom(2834)
		ptcawriter.write(msga)

		# make sure we get the same message
		self.assertEqual(msga, await ptsbreader.readexactly(len(msga)))

		# send a message larger than the block size
		msga = os.urandom(103958)
		ptcawriter.write(msga)

		# make sure we get the same message
		self.assertEqual(msga, await ptsbreader.readexactly(len(msga)))

		# send a message the other direction
		msga = os.urandom(103958)
		ptsbwriter.write(msga)

		# make sure we get the same message
		self.assertEqual(msga, await ptcareader.readexactly(len(msga)))

		# close down the pt writers, the rest should follow
		ptsbwriter.write_eof()
		ptcawriter.write_eof()

		# make sure they are closed, and there is no more data
		self.assertEqual(b'', await ptsbreader.read(1))
		self.assertTrue(ptsbreader.at_eof())
		self.assertEqual(b'', await ptcareader.read(1))
		self.assertTrue(ptcareader.at_eof())

		self.assertEqual([ 'dec', 'enc' ], await clientnf)
		self.assertEqual([ 'dec', 'enc' ], await servnf)

		await ptsbwriter.drain()
		await ptcawriter.drain()

		ptsbwriter.close()
		ptcawriter.close()