magic-wormhole/src/wormhole/cli/cmd_receive.py
2017-02-05 15:42:49 -08:00

364 lines
14 KiB
Python

from __future__ import print_function
import os, sys, six, tempfile, zipfile, hashlib, shutil
from tqdm import tqdm
from humanize import naturalsize
from twisted.internet import reactor
from twisted.internet.defer import inlineCallbacks, returnValue
from twisted.python import log
from ..wormhole import wormhole
from ..transit import TransitReceiver
from ..errors import TransferError, WormholeClosedError, NoTorError
from ..util import (dict_to_bytes, bytes_to_dict, bytes_to_hexstr,
estimate_free_space)
APPID = u"lothar.com/wormhole/text-or-file-xfer"
VERIFY_TIMER = 1
class RespondError(Exception):
def __init__(self, response):
self.response = response
class TransferRejectedError(RespondError):
def __init__(self):
RespondError.__init__(self, "transfer rejected")
def receive(args, reactor=reactor):
"""I implement 'wormhole receive'. I return a Deferred that fires with
None (for success), or signals one of the following errors:
* WrongPasswordError: the two sides didn't use matching passwords
* Timeout: something didn't happen fast enough for our tastes
* TransferError: the sender rejected the transfer: verifier mismatch
* any other error: something unexpected happened
"""
return TwistedReceiver(args, reactor).go()
class TwistedReceiver:
def __init__(self, args, reactor=reactor):
assert isinstance(args.relay_url, type(u""))
self.args = args
self._reactor = reactor
self._tor_manager = None
self._transit_receiver = None
def _msg(self, *args, **kwargs):
print(*args, file=self.args.stderr, **kwargs)
@inlineCallbacks
def go(self):
if self.args.tor:
with self.args.timing.add("import", which="tor_manager"):
from ..tor_manager import TorManager
self._tor_manager = TorManager(self._reactor,
self.args.launch_tor,
self.args.tor_control_port,
timing=self.args.timing)
if not self._tor_manager.tor_available():
raise NoTorError()
# For now, block everything until Tor has started. Soon: launch
# tor in parallel with everything else, make sure the TorManager
# can lazy-provide an endpoint, and overlap the startup process
# with the user handing off the wormhole code
yield self._tor_manager.start()
w = wormhole(self.args.appid or APPID, self.args.relay_url,
self._reactor, self._tor_manager, timing=self.args.timing)
# I wanted to do this instead:
#
# try:
# yield self._go(w, tor_manager)
# finally:
# yield w.close()
#
# but when _go had a UsageError, the stacktrace was always displayed
# as coming from the "yield self._go" line, which wasn't very useful
# for tracking it down.
d = self._go(w)
d.addBoth(w.close)
yield d
@inlineCallbacks
def _go(self, w):
yield self._handle_code(w)
yield w.establish_key()
def on_slow_connection():
print(u"Key established, waiting for confirmation...",
file=self.args.stderr)
notify = self._reactor.callLater(VERIFY_TIMER, on_slow_connection)
try:
verifier = yield w.verify()
finally:
if not notify.called:
notify.cancel()
self._show_verifier(verifier)
want_offer = True
done = False
while True:
try:
them_d = yield self._get_data(w)
except WormholeClosedError:
if done:
returnValue(None)
raise TransferError("unexpected close")
#print("GOT", them_d)
recognized = False
if u"transit" in them_d:
recognized = True
yield self._parse_transit(them_d[u"transit"], w)
if u"offer" in them_d:
recognized = True
if not want_offer:
raise TransferError("duplicate offer")
try:
yield self._parse_offer(them_d[u"offer"], w)
except RespondError as r:
self._send_data({"error": r.response}, w)
raise TransferError(r.response)
returnValue(None)
if not recognized:
log.msg("unrecognized message %r" % (them_d,))
def _send_data(self, data, w):
data_bytes = dict_to_bytes(data)
w.send(data_bytes)
@inlineCallbacks
def _get_data(self, w):
# this may raise WrongPasswordError
them_bytes = yield w.get()
them_d = bytes_to_dict(them_bytes)
if "error" in them_d:
raise TransferError(them_d["error"])
returnValue(them_d)
@inlineCallbacks
def _handle_code(self, w):
code = self.args.code
if self.args.zeromode:
assert not code
code = u"0-"
if code:
w.set_code(code)
else:
yield w.input_code("Enter receive wormhole code: ",
self.args.code_length)
def _show_verifier(self, verifier):
verifier_hex = bytes_to_hexstr(verifier)
if self.args.verify:
self._msg(u"Verifier %s." % verifier_hex)
@inlineCallbacks
def _parse_transit(self, sender_transit, w):
if self._transit_receiver:
# TODO: accept multiple messages, add the additional hints to the
# existing TransitReceiver
return
yield self._build_transit(w, sender_transit)
@inlineCallbacks
def _build_transit(self, w, sender_transit):
tr = TransitReceiver(self.args.transit_helper,
no_listen=(not self.args.listen),
tor_manager=self._tor_manager,
reactor=self._reactor,
timing=self.args.timing)
self._transit_receiver = tr
transit_key = w.derive_key(APPID+u"/transit-key", tr.TRANSIT_KEY_LENGTH)
tr.set_transit_key(transit_key)
tr.add_connection_hints(sender_transit.get("hints-v1", []))
receiver_abilities = tr.get_connection_abilities()
receiver_hints = yield tr.get_connection_hints()
receiver_transit = {"abilities-v1": receiver_abilities,
"hints-v1": receiver_hints,
}
self._send_data({u"transit": receiver_transit}, w)
# TODO: send more hints as the TransitReceiver produces them
@inlineCallbacks
def _parse_offer(self, them_d, w):
if "message" in them_d:
self._handle_text(them_d, w)
returnValue(None)
# transit will be created by this point, but not connected
if "file" in them_d:
f = self._handle_file(them_d)
self._send_permission(w)
rp = yield self._establish_transit()
datahash = yield self._transfer_data(rp, f)
self._write_file(f)
yield self._close_transit(rp, datahash)
elif "directory" in them_d:
f = self._handle_directory(them_d)
self._send_permission(w)
rp = yield self._establish_transit()
datahash = yield self._transfer_data(rp, f)
self._write_directory(f)
yield self._close_transit(rp, datahash)
else:
self._msg(u"I don't know what they're offering\n")
self._msg(u"Offer details: %r" % (them_d,))
raise RespondError("unknown offer type")
def _handle_text(self, them_d, w):
# we're receiving a text message
print(them_d["message"], file=self.args.stdout)
self._send_data({"answer": {"message_ack": "ok"}}, w)
def _handle_file(self, them_d):
file_data = them_d["file"]
self.abs_destname = self._decide_destname("file",
file_data["filename"])
self.xfersize = file_data["filesize"]
free = estimate_free_space(self.abs_destname)
if free is not None and free < self.xfersize:
self._msg(u"Error: insufficient free space (%sB) for file (%sB)"
% (free, self.xfersize))
raise TransferRejectedError()
self._msg(u"Receiving file (%s) into: %s" %
(naturalsize(self.xfersize), os.path.basename(self.abs_destname)))
self._ask_permission()
tmp_destname = self.abs_destname + ".tmp"
return open(tmp_destname, "wb")
def _handle_directory(self, them_d):
file_data = them_d["directory"]
zipmode = file_data["mode"]
if zipmode != "zipfile/deflated":
self._msg(u"Error: unknown directory-transfer mode '%s'" % (zipmode,))
raise RespondError("unknown mode")
self.abs_destname = self._decide_destname("directory",
file_data["dirname"])
self.xfersize = file_data["zipsize"]
free = estimate_free_space(self.abs_destname)
if free is not None and free < file_data["numbytes"]:
self._msg(u"Error: insufficient free space (%sB) for directory (%sB)"
% (free, file_data["numbytes"]))
raise TransferRejectedError()
self._msg(u"Receiving directory (%s) into: %s/" %
(naturalsize(self.xfersize), os.path.basename(self.abs_destname)))
self._msg(u"%d files, %s (uncompressed)" %
(file_data["numfiles"], naturalsize(file_data["numbytes"])))
self._ask_permission()
return tempfile.SpooledTemporaryFile()
def _decide_destname(self, mode, destname):
# the basename() is intended to protect us against
# "~/.ssh/authorized_keys" and other attacks
destname = os.path.basename(destname)
if self.args.output_file:
destname = self.args.output_file # override
abs_destname = os.path.abspath( os.path.join(self.args.cwd, destname) )
# get confirmation from the user before writing to the local directory
if os.path.exists(abs_destname):
if self.args.output_file: # overwrite is intentional
self._msg(u"Overwriting '%s'" % destname)
if self.args.accept_file:
self._remove_existing(abs_destname)
else:
self._msg(u"Error: refusing to overwrite existing '%s'" % destname)
raise TransferRejectedError()
return abs_destname
def _remove_existing(self, path):
if os.path.isfile(path): os.remove(path)
if os.path.isdir(path): shutil.rmtree(path)
def _ask_permission(self):
with self.args.timing.add("permission", waiting="user") as t:
while True and not self.args.accept_file:
ok = six.moves.input("ok? (y/n): ")
if ok.lower().startswith("y"):
if os.path.exists(self.abs_destname):
self._remove_existing(self.abs_destname)
break
print(u"transfer rejected", file=sys.stderr)
t.detail(answer="no")
raise TransferRejectedError()
t.detail(answer="yes")
def _send_permission(self, w):
self._send_data({"answer": { "file_ack": "ok" }}, w)
@inlineCallbacks
def _establish_transit(self):
record_pipe = yield self._transit_receiver.connect()
self.args.timing.add("transit connected")
returnValue(record_pipe)
@inlineCallbacks
def _transfer_data(self, record_pipe, f):
# now receive the rest of the owl
self._msg(u"Receiving (%s).." % record_pipe.describe())
with self.args.timing.add("rx file"):
progress = tqdm(file=self.args.stderr,
disable=self.args.hide_progress,
unit="B", unit_scale=True, total=self.xfersize)
hasher = hashlib.sha256()
with progress:
received = yield record_pipe.writeToFile(f, self.xfersize,
progress.update,
hasher.update)
datahash = hasher.digest()
# except TransitError
if received < self.xfersize:
self._msg()
self._msg(u"Connection dropped before full file received")
self._msg(u"got %d bytes, wanted %d" % (received, self.xfersize))
raise TransferError("Connection dropped before full file received")
assert received == self.xfersize
returnValue(datahash)
def _write_file(self, f):
tmp_name = f.name
f.close()
os.rename(tmp_name, self.abs_destname)
self._msg(u"Received file written to %s" %
os.path.basename(self.abs_destname))
def _extract_file(self, zf, info, extract_dir):
"""
the zipfile module does not restore file permissions
so we'll do it manually
"""
out_path = os.path.join( extract_dir, info.filename )
out_path = os.path.abspath( out_path )
if not out_path.startswith( extract_dir ):
raise ValueError( "malicious zipfile, %s outside of extract_dir %s"
% (info.filename, extract_dir) )
zf.extract( info.filename, path=extract_dir )
# not sure why zipfiles store the perms 16 bits away but they do
perm = info.external_attr >> 16
os.chmod( out_path, perm )
def _write_directory(self, f):
self._msg(u"Unpacking zipfile..")
with self.args.timing.add("unpack zip"):
with zipfile.ZipFile(f, "r", zipfile.ZIP_DEFLATED) as zf:
for info in zf.infolist():
self._extract_file( zf, info, self.abs_destname )
self._msg(u"Received files written to %s/" %
os.path.basename(self.abs_destname))
f.close()
@inlineCallbacks
def _close_transit(self, record_pipe, datahash):
datahash_hex = bytes_to_hexstr(datahash)
ack = {u"ack": u"ok", u"sha256": datahash_hex}
ack_bytes = dict_to_bytes(ack)
with self.args.timing.add("send ack"):
yield record_pipe.send_record(ack_bytes)
yield record_pipe.close()