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19 """
20 L{Transport} handles the core SSH2 protocol.
21 """
22
23 import os
24 import socket
25 import string
26 import struct
27 import sys
28 import threading
29 import time
30 import weakref
31
32 import ssh
33 from ssh import util
34 from ssh.auth_handler import AuthHandler
35 from ssh.channel import Channel
36 from ssh.common import *
37 from ssh.compress import ZlibCompressor, ZlibDecompressor
38 from ssh.dsskey import DSSKey
39 from ssh.kex_gex import KexGex
40 from ssh.kex_group1 import KexGroup1
41 from ssh.message import Message
42 from ssh.packet import Packetizer, NeedRekeyException
43 from ssh.primes import ModulusPack
44 from ssh.rsakey import RSAKey
45 from ssh.server import ServerInterface
46 from ssh.sftp_client import SFTPClient
47 from ssh.ssh_exception import SSHException, BadAuthenticationType, ChannelException
48
49 from Crypto import Random
50 from Crypto.Cipher import Blowfish, AES, DES3, ARC4
51 from Crypto.Hash import SHA, MD5
52 try:
53 from Crypto.Util import Counter
54 except ImportError:
55 from ssh.util import Counter
56
57
58
59 _active_threads = []
63 import atexit
64 atexit.register(_join_lingering_threads)
65
66
68 """
69 Simple object containing the security preferences of an ssh transport.
70 These are tuples of acceptable ciphers, digests, key types, and key
71 exchange algorithms, listed in order of preference.
72
73 Changing the contents and/or order of these fields affects the underlying
74 L{Transport} (but only if you change them before starting the session).
75 If you try to add an algorithm that ssh doesn't recognize,
76 C{ValueError} will be raised. If you try to assign something besides a
77 tuple to one of the fields, C{TypeError} will be raised.
78 """
79 __slots__ = [ 'ciphers', 'digests', 'key_types', 'kex', 'compression', '_transport' ]
80
83
85 """
86 Returns a string representation of this object, for debugging.
87
88 @rtype: str
89 """
90 return '<ssh.SecurityOptions for %s>' % repr(self._transport)
91
94
97
100
103
106
107 - def _set(self, name, orig, x):
108 if type(x) is list:
109 x = tuple(x)
110 if type(x) is not tuple:
111 raise TypeError('expected tuple or list')
112 possible = getattr(self._transport, orig).keys()
113 forbidden = filter(lambda n: n not in possible, x)
114 if len(forbidden) > 0:
115 raise ValueError('unknown cipher')
116 setattr(self._transport, name, x)
117
119 self._set('_preferred_ciphers', '_cipher_info', x)
120
122 self._set('_preferred_macs', '_mac_info', x)
123
125 self._set('_preferred_keys', '_key_info', x)
126
128 self._set('_preferred_kex', '_kex_info', x)
129
131 self._set('_preferred_compression', '_compression_info', x)
132
133 ciphers = property(_get_ciphers, _set_ciphers, None,
134 "Symmetric encryption ciphers")
135 digests = property(_get_digests, _set_digests, None,
136 "Digest (one-way hash) algorithms")
137 key_types = property(_get_key_types, _set_key_types, None,
138 "Public-key algorithms")
139 kex = property(_get_kex, _set_kex, None, "Key exchange algorithms")
140 compression = property(_get_compression, _set_compression, None,
141 "Compression algorithms")
142
143
146
147 self._map = weakref.WeakValueDictionary()
148 self._lock = threading.Lock()
149
150 - def put(self, chanid, chan):
151 self._lock.acquire()
152 try:
153 self._map[chanid] = chan
154 finally:
155 self._lock.release()
156
157 - def get(self, chanid):
158 self._lock.acquire()
159 try:
160 return self._map.get(chanid, None)
161 finally:
162 self._lock.release()
163
165 self._lock.acquire()
166 try:
167 try:
168 del self._map[chanid]
169 except KeyError:
170 pass
171 finally:
172 self._lock.release()
173
175 self._lock.acquire()
176 try:
177 return self._map.values()
178 finally:
179 self._lock.release()
180
182 self._lock.acquire()
183 try:
184 return len(self._map)
185 finally:
186 self._lock.release()
187
188
190 """
191 An SSH Transport attaches to a stream (usually a socket), negotiates an
192 encrypted session, authenticates, and then creates stream tunnels, called
193 L{Channel}s, across the session. Multiple channels can be multiplexed
194 across a single session (and often are, in the case of port forwardings).
195 """
196
197 _PROTO_ID = '2.0'
198 _CLIENT_ID = 'ssh_%s' % (ssh.__version__)
199
200 _preferred_ciphers = ( 'aes128-ctr', 'aes256-ctr', 'aes128-cbc', 'blowfish-cbc', 'aes256-cbc', '3des-cbc',
201 'arcfour128', 'arcfour256' )
202 _preferred_macs = ( 'hmac-sha1', 'hmac-md5', 'hmac-sha1-96', 'hmac-md5-96' )
203 _preferred_keys = ( 'ssh-rsa', 'ssh-dss' )
204 _preferred_kex = ( 'diffie-hellman-group1-sha1', 'diffie-hellman-group-exchange-sha1' )
205 _preferred_compression = ( 'none', )
206
207 _cipher_info = {
208 'aes128-ctr': { 'class': AES, 'mode': AES.MODE_CTR, 'block-size': 16, 'key-size': 16 },
209 'aes256-ctr': { 'class': AES, 'mode': AES.MODE_CTR, 'block-size': 16, 'key-size': 32 },
210 'blowfish-cbc': { 'class': Blowfish, 'mode': Blowfish.MODE_CBC, 'block-size': 8, 'key-size': 16 },
211 'aes128-cbc': { 'class': AES, 'mode': AES.MODE_CBC, 'block-size': 16, 'key-size': 16 },
212 'aes256-cbc': { 'class': AES, 'mode': AES.MODE_CBC, 'block-size': 16, 'key-size': 32 },
213 '3des-cbc': { 'class': DES3, 'mode': DES3.MODE_CBC, 'block-size': 8, 'key-size': 24 },
214 'arcfour128': { 'class': ARC4, 'mode': None, 'block-size': 8, 'key-size': 16 },
215 'arcfour256': { 'class': ARC4, 'mode': None, 'block-size': 8, 'key-size': 32 },
216 }
217
218 _mac_info = {
219 'hmac-sha1': { 'class': SHA, 'size': 20 },
220 'hmac-sha1-96': { 'class': SHA, 'size': 12 },
221 'hmac-md5': { 'class': MD5, 'size': 16 },
222 'hmac-md5-96': { 'class': MD5, 'size': 12 },
223 }
224
225 _key_info = {
226 'ssh-rsa': RSAKey,
227 'ssh-dss': DSSKey,
228 }
229
230 _kex_info = {
231 'diffie-hellman-group1-sha1': KexGroup1,
232 'diffie-hellman-group-exchange-sha1': KexGex,
233 }
234
235 _compression_info = {
236
237
238
239 'zlib@openssh.com': ( ZlibCompressor, ZlibDecompressor ),
240 'zlib': ( ZlibCompressor, ZlibDecompressor ),
241 'none': ( None, None ),
242 }
243
244
245 _modulus_pack = None
246
248 """
249 Create a new SSH session over an existing socket, or socket-like
250 object. This only creates the Transport object; it doesn't begin the
251 SSH session yet. Use L{connect} or L{start_client} to begin a client
252 session, or L{start_server} to begin a server session.
253
254 If the object is not actually a socket, it must have the following
255 methods:
256 - C{send(str)}: Writes from 1 to C{len(str)} bytes, and
257 returns an int representing the number of bytes written. Returns
258 0 or raises C{EOFError} if the stream has been closed.
259 - C{recv(int)}: Reads from 1 to C{int} bytes and returns them as a
260 string. Returns 0 or raises C{EOFError} if the stream has been
261 closed.
262 - C{close()}: Closes the socket.
263 - C{settimeout(n)}: Sets a (float) timeout on I/O operations.
264
265 For ease of use, you may also pass in an address (as a tuple) or a host
266 string as the C{sock} argument. (A host string is a hostname with an
267 optional port (separated by C{":"}) which will be converted into a
268 tuple of C{(hostname, port)}.) A socket will be connected to this
269 address and used for communication. Exceptions from the C{socket} call
270 may be thrown in this case.
271
272 @param sock: a socket or socket-like object to create the session over.
273 @type sock: socket
274 """
275 if isinstance(sock, (str, unicode)):
276
277 hl = sock.split(':', 1)
278 if len(hl) == 1:
279 sock = (hl[0], 22)
280 else:
281 sock = (hl[0], int(hl[1]))
282 if type(sock) is tuple:
283
284 hostname, port = sock
285 reason = 'No suitable address family'
286 for (family, socktype, proto, canonname, sockaddr) in socket.getaddrinfo(hostname, port, socket.AF_UNSPEC, socket.SOCK_STREAM):
287 if socktype == socket.SOCK_STREAM:
288 af = family
289 addr = sockaddr
290 sock = socket.socket(af, socket.SOCK_STREAM)
291 try:
292 sock.connect((hostname, port))
293 except socket.error, e:
294 reason = str(e)
295 else:
296 break
297 else:
298 raise SSHException(
299 'Unable to connect to %s: %s' % (hostname, reason))
300
301 threading.Thread.__init__(self)
302 self.setDaemon(True)
303 self.rng = rng
304 self.sock = sock
305
306 try:
307
308
309
310 self.sock.settimeout(0.1)
311 except AttributeError:
312 pass
313
314
315 self.packetizer = Packetizer(sock)
316 self.local_version = 'SSH-' + self._PROTO_ID + '-' + self._CLIENT_ID
317 self.remote_version = ''
318 self.local_cipher = self.remote_cipher = ''
319 self.local_kex_init = self.remote_kex_init = None
320 self.local_mac = self.remote_mac = None
321 self.local_compression = self.remote_compression = None
322 self.session_id = None
323 self.host_key_type = None
324 self.host_key = None
325
326
327 self.kex_engine = None
328 self.H = None
329 self.K = None
330
331 self.active = False
332 self.initial_kex_done = False
333 self.in_kex = False
334 self.authenticated = False
335 self._expected_packet = tuple()
336 self.lock = threading.Lock()
337
338
339 self._channels = ChannelMap()
340 self.channel_events = { }
341 self.channels_seen = { }
342 self._channel_counter = 1
343 self.window_size = 65536
344 self.max_packet_size = 34816
345 self._x11_handler = None
346 self._tcp_handler = None
347
348 self.saved_exception = None
349 self.clear_to_send = threading.Event()
350 self.clear_to_send_lock = threading.Lock()
351 self.clear_to_send_timeout = 30.0
352 self.log_name = 'ssh.transport'
353 self.logger = util.get_logger(self.log_name)
354 self.packetizer.set_log(self.logger)
355 self.auth_handler = None
356 self.global_response = None
357 self.completion_event = None
358 self.banner_timeout = 15
359
360
361 self.server_mode = False
362 self.server_object = None
363 self.server_key_dict = { }
364 self.server_accepts = [ ]
365 self.server_accept_cv = threading.Condition(self.lock)
366 self.subsystem_table = { }
367
369 """
370 Returns a string representation of this object, for debugging.
371
372 @rtype: str
373 """
374 out = '<ssh.Transport at %s' % hex(long(id(self)) & 0xffffffffL)
375 if not self.active:
376 out += ' (unconnected)'
377 else:
378 if self.local_cipher != '':
379 out += ' (cipher %s, %d bits)' % (self.local_cipher,
380 self._cipher_info[self.local_cipher]['key-size'] * 8)
381 if self.is_authenticated():
382 out += ' (active; %d open channel(s))' % len(self._channels)
383 elif self.initial_kex_done:
384 out += ' (connected; awaiting auth)'
385 else:
386 out += ' (connecting)'
387 out += '>'
388 return out
389
391 """
392 Terminate this Transport without closing the session. On posix
393 systems, if a Transport is open during process forking, both parent
394 and child will share the underlying socket, but only one process can
395 use the connection (without corrupting the session). Use this method
396 to clean up a Transport object without disrupting the other process.
397
398 @since: 1.5.3
399 """
400 self.sock.close()
401 self.close()
402
404 """
405 Return a L{SecurityOptions} object which can be used to tweak the
406 encryption algorithms this transport will permit, and the order of
407 preference for them.
408
409 @return: an object that can be used to change the preferred algorithms
410 for encryption, digest (hash), public key, and key exchange.
411 @rtype: L{SecurityOptions}
412 """
413 return SecurityOptions(self)
414
416 """
417 Negotiate a new SSH2 session as a client. This is the first step after
418 creating a new L{Transport}. A separate thread is created for protocol
419 negotiation.
420
421 If an event is passed in, this method returns immediately. When
422 negotiation is done (successful or not), the given C{Event} will
423 be triggered. On failure, L{is_active} will return C{False}.
424
425 (Since 1.4) If C{event} is C{None}, this method will not return until
426 negotation is done. On success, the method returns normally.
427 Otherwise an SSHException is raised.
428
429 After a successful negotiation, you will usually want to authenticate,
430 calling L{auth_password <Transport.auth_password>} or
431 L{auth_publickey <Transport.auth_publickey>}.
432
433 @note: L{connect} is a simpler method for connecting as a client.
434
435 @note: After calling this method (or L{start_server} or L{connect}),
436 you should no longer directly read from or write to the original
437 socket object.
438
439 @param event: an event to trigger when negotiation is complete
440 (optional)
441 @type event: threading.Event
442
443 @raise SSHException: if negotiation fails (and no C{event} was passed
444 in)
445 """
446 self.active = True
447 if event is not None:
448
449 self.completion_event = event
450 self.start()
451 return
452
453
454 self.completion_event = event = threading.Event()
455 self.start()
456 Random.atfork()
457 while True:
458 event.wait(0.1)
459 if not self.active:
460 e = self.get_exception()
461 if e is not None:
462 raise e
463 raise SSHException('Negotiation failed.')
464 if event.isSet():
465 break
466
468 """
469 Negotiate a new SSH2 session as a server. This is the first step after
470 creating a new L{Transport} and setting up your server host key(s). A
471 separate thread is created for protocol negotiation.
472
473 If an event is passed in, this method returns immediately. When
474 negotiation is done (successful or not), the given C{Event} will
475 be triggered. On failure, L{is_active} will return C{False}.
476
477 (Since 1.4) If C{event} is C{None}, this method will not return until
478 negotation is done. On success, the method returns normally.
479 Otherwise an SSHException is raised.
480
481 After a successful negotiation, the client will need to authenticate.
482 Override the methods
483 L{get_allowed_auths <ServerInterface.get_allowed_auths>},
484 L{check_auth_none <ServerInterface.check_auth_none>},
485 L{check_auth_password <ServerInterface.check_auth_password>}, and
486 L{check_auth_publickey <ServerInterface.check_auth_publickey>} in the
487 given C{server} object to control the authentication process.
488
489 After a successful authentication, the client should request to open
490 a channel. Override
491 L{check_channel_request <ServerInterface.check_channel_request>} in the
492 given C{server} object to allow channels to be opened.
493
494 @note: After calling this method (or L{start_client} or L{connect}),
495 you should no longer directly read from or write to the original
496 socket object.
497
498 @param event: an event to trigger when negotiation is complete.
499 @type event: threading.Event
500 @param server: an object used to perform authentication and create
501 L{Channel}s.
502 @type server: L{server.ServerInterface}
503
504 @raise SSHException: if negotiation fails (and no C{event} was passed
505 in)
506 """
507 if server is None:
508 server = ServerInterface()
509 self.server_mode = True
510 self.server_object = server
511 self.active = True
512 if event is not None:
513
514 self.completion_event = event
515 self.start()
516 return
517
518
519 self.completion_event = event = threading.Event()
520 self.start()
521 while True:
522 event.wait(0.1)
523 if not self.active:
524 e = self.get_exception()
525 if e is not None:
526 raise e
527 raise SSHException('Negotiation failed.')
528 if event.isSet():
529 break
530
532 """
533 Add a host key to the list of keys used for server mode. When behaving
534 as a server, the host key is used to sign certain packets during the
535 SSH2 negotiation, so that the client can trust that we are who we say
536 we are. Because this is used for signing, the key must contain private
537 key info, not just the public half. Only one key of each type (RSA or
538 DSS) is kept.
539
540 @param key: the host key to add, usually an L{RSAKey <rsakey.RSAKey>} or
541 L{DSSKey <dsskey.DSSKey>}.
542 @type key: L{PKey <pkey.PKey>}
543 """
544 self.server_key_dict[key.get_name()] = key
545
547 """
548 Return the active host key, in server mode. After negotiating with the
549 client, this method will return the negotiated host key. If only one
550 type of host key was set with L{add_server_key}, that's the only key
551 that will ever be returned. But in cases where you have set more than
552 one type of host key (for example, an RSA key and a DSS key), the key
553 type will be negotiated by the client, and this method will return the
554 key of the type agreed on. If the host key has not been negotiated
555 yet, C{None} is returned. In client mode, the behavior is undefined.
556
557 @return: host key of the type negotiated by the client, or C{None}.
558 @rtype: L{PKey <pkey.PKey>}
559 """
560 try:
561 return self.server_key_dict[self.host_key_type]
562 except KeyError:
563 pass
564 return None
565
567 """
568 I{(optional)}
569 Load a file of prime moduli for use in doing group-exchange key
570 negotiation in server mode. It's a rather obscure option and can be
571 safely ignored.
572
573 In server mode, the remote client may request "group-exchange" key
574 negotiation, which asks the server to send a random prime number that
575 fits certain criteria. These primes are pretty difficult to compute,
576 so they can't be generated on demand. But many systems contain a file
577 of suitable primes (usually named something like C{/etc/ssh/moduli}).
578 If you call C{load_server_moduli} and it returns C{True}, then this
579 file of primes has been loaded and we will support "group-exchange" in
580 server mode. Otherwise server mode will just claim that it doesn't
581 support that method of key negotiation.
582
583 @param filename: optional path to the moduli file, if you happen to
584 know that it's not in a standard location.
585 @type filename: str
586 @return: True if a moduli file was successfully loaded; False
587 otherwise.
588 @rtype: bool
589
590 @note: This has no effect when used in client mode.
591 """
592 Transport._modulus_pack = ModulusPack(rng)
593
594 file_list = [ '/etc/ssh/moduli', '/usr/local/etc/moduli' ]
595 if filename is not None:
596 file_list.insert(0, filename)
597 for fn in file_list:
598 try:
599 Transport._modulus_pack.read_file(fn)
600 return True
601 except IOError:
602 pass
603
604 Transport._modulus_pack = None
605 return False
606 load_server_moduli = staticmethod(load_server_moduli)
607
609 """
610 Close this session, and any open channels that are tied to it.
611 """
612 if not self.active:
613 return
614 self.active = False
615 self.packetizer.close()
616 self.join()
617 for chan in self._channels.values():
618 chan._unlink()
619
621 """
622 Return the host key of the server (in client mode).
623
624 @note: Previously this call returned a tuple of (key type, key string).
625 You can get the same effect by calling
626 L{PKey.get_name <pkey.PKey.get_name>} for the key type, and
627 C{str(key)} for the key string.
628
629 @raise SSHException: if no session is currently active.
630
631 @return: public key of the remote server
632 @rtype: L{PKey <pkey.PKey>}
633 """
634 if (not self.active) or (not self.initial_kex_done):
635 raise SSHException('No existing session')
636 return self.host_key
637
639 """
640 Return true if this session is active (open).
641
642 @return: True if the session is still active (open); False if the
643 session is closed
644 @rtype: bool
645 """
646 return self.active
647
649 """
650 Request a new channel to the server, of type C{"session"}. This
651 is just an alias for C{open_channel('session')}.
652
653 @return: a new L{Channel}
654 @rtype: L{Channel}
655
656 @raise SSHException: if the request is rejected or the session ends
657 prematurely
658 """
659 return self.open_channel('session')
660
662 """
663 Request a new channel to the client, of type C{"x11"}. This
664 is just an alias for C{open_channel('x11', src_addr=src_addr)}.
665
666 @param src_addr: the source address of the x11 server (port is the
667 x11 port, ie. 6010)
668 @type src_addr: (str, int)
669 @return: a new L{Channel}
670 @rtype: L{Channel}
671
672 @raise SSHException: if the request is rejected or the session ends
673 prematurely
674 """
675 return self.open_channel('x11', src_addr=src_addr)
676
678 """
679 Request a new channel back to the client, of type C{"forwarded-tcpip"}.
680 This is used after a client has requested port forwarding, for sending
681 incoming connections back to the client.
682
683 @param src_addr: originator's address
684 @param src_port: originator's port
685 @param dest_addr: local (server) connected address
686 @param dest_port: local (server) connected port
687 """
688 return self.open_channel('forwarded-tcpip', (dest_addr, dest_port), (src_addr, src_port))
689
690 - def open_channel(self, kind, dest_addr=None, src_addr=None):
691 """
692 Request a new channel to the server. L{Channel}s are socket-like
693 objects used for the actual transfer of data across the session.
694 You may only request a channel after negotiating encryption (using
695 L{connect} or L{start_client}) and authenticating.
696
697 @param kind: the kind of channel requested (usually C{"session"},
698 C{"forwarded-tcpip"}, C{"direct-tcpip"}, or C{"x11"})
699 @type kind: str
700 @param dest_addr: the destination address of this port forwarding,
701 if C{kind} is C{"forwarded-tcpip"} or C{"direct-tcpip"} (ignored
702 for other channel types)
703 @type dest_addr: (str, int)
704 @param src_addr: the source address of this port forwarding, if
705 C{kind} is C{"forwarded-tcpip"}, C{"direct-tcpip"}, or C{"x11"}
706 @type src_addr: (str, int)
707 @return: a new L{Channel} on success
708 @rtype: L{Channel}
709
710 @raise SSHException: if the request is rejected or the session ends
711 prematurely
712 """
713 if not self.active:
714 raise SSHException('SSH session not active')
715 self.lock.acquire()
716 try:
717 chanid = self._next_channel()
718 m = Message()
719 m.add_byte(chr(MSG_CHANNEL_OPEN))
720 m.add_string(kind)
721 m.add_int(chanid)
722 m.add_int(self.window_size)
723 m.add_int(self.max_packet_size)
724 if (kind == 'forwarded-tcpip') or (kind == 'direct-tcpip'):
725 m.add_string(dest_addr[0])
726 m.add_int(dest_addr[1])
727 m.add_string(src_addr[0])
728 m.add_int(src_addr[1])
729 elif kind == 'x11':
730 m.add_string(src_addr[0])
731 m.add_int(src_addr[1])
732 chan = Channel(chanid)
733 self._channels.put(chanid, chan)
734 self.channel_events[chanid] = event = threading.Event()
735 self.channels_seen[chanid] = True
736 chan._set_transport(self)
737 chan._set_window(self.window_size, self.max_packet_size)
738 finally:
739 self.lock.release()
740 self._send_user_message(m)
741 while True:
742 event.wait(0.1);
743 if not self.active:
744 e = self.get_exception()
745 if e is None:
746 e = SSHException('Unable to open channel.')
747 raise e
748 if event.isSet():
749 break
750 chan = self._channels.get(chanid)
751 if chan is not None:
752 return chan
753 e = self.get_exception()
754 if e is None:
755 e = SSHException('Unable to open channel.')
756 raise e
757
759 """
760 Ask the server to forward TCP connections from a listening port on
761 the server, across this SSH session.
762
763 If a handler is given, that handler is called from a different thread
764 whenever a forwarded connection arrives. The handler parameters are::
765
766 handler(channel, (origin_addr, origin_port), (server_addr, server_port))
767
768 where C{server_addr} and C{server_port} are the address and port that
769 the server was listening on.
770
771 If no handler is set, the default behavior is to send new incoming
772 forwarded connections into the accept queue, to be picked up via
773 L{accept}.
774
775 @param address: the address to bind when forwarding
776 @type address: str
777 @param port: the port to forward, or 0 to ask the server to allocate
778 any port
779 @type port: int
780 @param handler: optional handler for incoming forwarded connections
781 @type handler: function(Channel, (str, int), (str, int))
782 @return: the port # allocated by the server
783 @rtype: int
784
785 @raise SSHException: if the server refused the TCP forward request
786 """
787 if not self.active:
788 raise SSHException('SSH session not active')
789 address = str(address)
790 port = int(port)
791 response = self.global_request('tcpip-forward', (address, port), wait=True)
792 if response is None:
793 raise SSHException('TCP forwarding request denied')
794 if port == 0:
795 port = response.get_int()
796 if handler is None:
797 def default_handler(channel, (src_addr, src_port), (dest_addr, dest_port)):
798 self._queue_incoming_channel(channel)
799 handler = default_handler
800 self._tcp_handler = handler
801 return port
802
804 """
805 Ask the server to cancel a previous port-forwarding request. No more
806 connections to the given address & port will be forwarded across this
807 ssh connection.
808
809 @param address: the address to stop forwarding
810 @type address: str
811 @param port: the port to stop forwarding
812 @type port: int
813 """
814 if not self.active:
815 return
816 self._tcp_handler = None
817 self.global_request('cancel-tcpip-forward', (address, port), wait=True)
818
820 """
821 Create an SFTP client channel from an open transport. On success,
822 an SFTP session will be opened with the remote host, and a new
823 SFTPClient object will be returned.
824
825 @return: a new L{SFTPClient} object, referring to an sftp session
826 (channel) across this transport
827 @rtype: L{SFTPClient}
828 """
829 return SFTPClient.from_transport(self)
830
832 """
833 Send a junk packet across the encrypted link. This is sometimes used
834 to add "noise" to a connection to confuse would-be attackers. It can
835 also be used as a keep-alive for long lived connections traversing
836 firewalls.
837
838 @param bytes: the number of random bytes to send in the payload of the
839 ignored packet -- defaults to a random number from 10 to 41.
840 @type bytes: int
841 """
842 m = Message()
843 m.add_byte(chr(MSG_IGNORE))
844 if bytes is None:
845 bytes = (ord(rng.read(1)) % 32) + 10
846 m.add_bytes(rng.read(bytes))
847 self._send_user_message(m)
848
850 """
851 Force this session to switch to new keys. Normally this is done
852 automatically after the session hits a certain number of packets or
853 bytes sent or received, but this method gives you the option of forcing
854 new keys whenever you want. Negotiating new keys causes a pause in
855 traffic both ways as the two sides swap keys and do computations. This
856 method returns when the session has switched to new keys.
857
858 @raise SSHException: if the key renegotiation failed (which causes the
859 session to end)
860 """
861 self.completion_event = threading.Event()
862 self._send_kex_init()
863 while True:
864 self.completion_event.wait(0.1)
865 if not self.active:
866 e = self.get_exception()
867 if e is not None:
868 raise e
869 raise SSHException('Negotiation failed.')
870 if self.completion_event.isSet():
871 break
872 return
873
875 """
876 Turn on/off keepalive packets (default is off). If this is set, after
877 C{interval} seconds without sending any data over the connection, a
878 "keepalive" packet will be sent (and ignored by the remote host). This
879 can be useful to keep connections alive over a NAT, for example.
880
881 @param interval: seconds to wait before sending a keepalive packet (or
882 0 to disable keepalives).
883 @type interval: int
884 """
885 self.packetizer.set_keepalive(interval,
886 lambda x=weakref.proxy(self): x.global_request('keepalive@lag.net', wait=False))
887
889 """
890 Make a global request to the remote host. These are normally
891 extensions to the SSH2 protocol.
892
893 @param kind: name of the request.
894 @type kind: str
895 @param data: an optional tuple containing additional data to attach
896 to the request.
897 @type data: tuple
898 @param wait: C{True} if this method should not return until a response
899 is received; C{False} otherwise.
900 @type wait: bool
901 @return: a L{Message} containing possible additional data if the
902 request was successful (or an empty L{Message} if C{wait} was
903 C{False}); C{None} if the request was denied.
904 @rtype: L{Message}
905 """
906 if wait:
907 self.completion_event = threading.Event()
908 m = Message()
909 m.add_byte(chr(MSG_GLOBAL_REQUEST))
910 m.add_string(kind)
911 m.add_boolean(wait)
912 if data is not None:
913 m.add(*data)
914 self._log(DEBUG, 'Sending global request "%s"' % kind)
915 self._send_user_message(m)
916 if not wait:
917 return None
918 while True:
919 self.completion_event.wait(0.1)
920 if not self.active:
921 return None
922 if self.completion_event.isSet():
923 break
924 return self.global_response
925
926 - def accept(self, timeout=None):
927 """
928 Return the next channel opened by the client over this transport, in
929 server mode. If no channel is opened before the given timeout, C{None}
930 is returned.
931
932 @param timeout: seconds to wait for a channel, or C{None} to wait
933 forever
934 @type timeout: int
935 @return: a new Channel opened by the client
936 @rtype: L{Channel}
937 """
938 self.lock.acquire()
939 try:
940 if len(self.server_accepts) > 0:
941 chan = self.server_accepts.pop(0)
942 else:
943 self.server_accept_cv.wait(timeout)
944 if len(self.server_accepts) > 0:
945 chan = self.server_accepts.pop(0)
946 else:
947
948 chan = None
949 finally:
950 self.lock.release()
951 return chan
952
953 - def connect(self, hostkey=None, username='', password=None, pkey=None):
954 """
955 Negotiate an SSH2 session, and optionally verify the server's host key
956 and authenticate using a password or private key. This is a shortcut
957 for L{start_client}, L{get_remote_server_key}, and
958 L{Transport.auth_password} or L{Transport.auth_publickey}. Use those
959 methods if you want more control.
960
961 You can use this method immediately after creating a Transport to
962 negotiate encryption with a server. If it fails, an exception will be
963 thrown. On success, the method will return cleanly, and an encrypted
964 session exists. You may immediately call L{open_channel} or
965 L{open_session} to get a L{Channel} object, which is used for data
966 transfer.
967
968 @note: If you fail to supply a password or private key, this method may
969 succeed, but a subsequent L{open_channel} or L{open_session} call may
970 fail because you haven't authenticated yet.
971
972 @param hostkey: the host key expected from the server, or C{None} if
973 you don't want to do host key verification.
974 @type hostkey: L{PKey<pkey.PKey>}
975 @param username: the username to authenticate as.
976 @type username: str
977 @param password: a password to use for authentication, if you want to
978 use password authentication; otherwise C{None}.
979 @type password: str
980 @param pkey: a private key to use for authentication, if you want to
981 use private key authentication; otherwise C{None}.
982 @type pkey: L{PKey<pkey.PKey>}
983
984 @raise SSHException: if the SSH2 negotiation fails, the host key
985 supplied by the server is incorrect, or authentication fails.
986 """
987 if hostkey is not None:
988 self._preferred_keys = [ hostkey.get_name() ]
989
990 self.start_client()
991
992
993 if (hostkey is not None):
994 key = self.get_remote_server_key()
995 if (key.get_name() != hostkey.get_name()) or (str(key) != str(hostkey)):
996 self._log(DEBUG, 'Bad host key from server')
997 self._log(DEBUG, 'Expected: %s: %s' % (hostkey.get_name(), repr(str(hostkey))))
998 self._log(DEBUG, 'Got : %s: %s' % (key.get_name(), repr(str(key))))
999 raise SSHException('Bad host key from server')
1000 self._log(DEBUG, 'Host key verified (%s)' % hostkey.get_name())
1001
1002 if (pkey is not None) or (password is not None):
1003 if password is not None:
1004 self._log(DEBUG, 'Attempting password auth...')
1005 self.auth_password(username, password)
1006 else:
1007 self._log(DEBUG, 'Attempting public-key auth...')
1008 self.auth_publickey(username, pkey)
1009
1010 return
1011
1013 """
1014 Return any exception that happened during the last server request.
1015 This can be used to fetch more specific error information after using
1016 calls like L{start_client}. The exception (if any) is cleared after
1017 this call.
1018
1019 @return: an exception, or C{None} if there is no stored exception.
1020 @rtype: Exception
1021
1022 @since: 1.1
1023 """
1024 self.lock.acquire()
1025 try:
1026 e = self.saved_exception
1027 self.saved_exception = None
1028 return e
1029 finally:
1030 self.lock.release()
1031
1033 """
1034 Set the handler class for a subsystem in server mode. If a request
1035 for this subsystem is made on an open ssh channel later, this handler
1036 will be constructed and called -- see L{SubsystemHandler} for more
1037 detailed documentation.
1038
1039 Any extra parameters (including keyword arguments) are saved and
1040 passed to the L{SubsystemHandler} constructor later.
1041
1042 @param name: name of the subsystem.
1043 @type name: str
1044 @param handler: subclass of L{SubsystemHandler} that handles this
1045 subsystem.
1046 @type handler: class
1047 """
1048 try:
1049 self.lock.acquire()
1050 self.subsystem_table[name] = (handler, larg, kwarg)
1051 finally:
1052 self.lock.release()
1053
1055 """
1056 Return true if this session is active and authenticated.
1057
1058 @return: True if the session is still open and has been authenticated
1059 successfully; False if authentication failed and/or the session is
1060 closed.
1061 @rtype: bool
1062 """
1063 return self.active and (self.auth_handler is not None) and self.auth_handler.is_authenticated()
1064
1066 """
1067 Return the username this connection is authenticated for. If the
1068 session is not authenticated (or authentication failed), this method
1069 returns C{None}.
1070
1071 @return: username that was authenticated, or C{None}.
1072 @rtype: string
1073 """
1074 if not self.active or (self.auth_handler is None):
1075 return None
1076 return self.auth_handler.get_username()
1077
1079 """
1080 Try to authenticate to the server using no authentication at all.
1081 This will almost always fail. It may be useful for determining the
1082 list of authentication types supported by the server, by catching the
1083 L{BadAuthenticationType} exception raised.
1084
1085 @param username: the username to authenticate as
1086 @type username: string
1087 @return: list of auth types permissible for the next stage of
1088 authentication (normally empty)
1089 @rtype: list
1090
1091 @raise BadAuthenticationType: if "none" authentication isn't allowed
1092 by the server for this user
1093 @raise SSHException: if the authentication failed due to a network
1094 error
1095
1096 @since: 1.5
1097 """
1098 if (not self.active) or (not self.initial_kex_done):
1099 raise SSHException('No existing session')
1100 my_event = threading.Event()
1101 self.auth_handler = AuthHandler(self)
1102 self.auth_handler.auth_none(username, my_event)
1103 return self.auth_handler.wait_for_response(my_event)
1104
1105 - def auth_password(self, username, password, event=None, fallback=True):
1106 """
1107 Authenticate to the server using a password. The username and password
1108 are sent over an encrypted link.
1109
1110 If an C{event} is passed in, this method will return immediately, and
1111 the event will be triggered once authentication succeeds or fails. On
1112 success, L{is_authenticated} will return C{True}. On failure, you may
1113 use L{get_exception} to get more detailed error information.
1114
1115 Since 1.1, if no event is passed, this method will block until the
1116 authentication succeeds or fails. On failure, an exception is raised.
1117 Otherwise, the method simply returns.
1118
1119 Since 1.5, if no event is passed and C{fallback} is C{True} (the
1120 default), if the server doesn't support plain password authentication
1121 but does support so-called "keyboard-interactive" mode, an attempt
1122 will be made to authenticate using this interactive mode. If it fails,
1123 the normal exception will be thrown as if the attempt had never been
1124 made. This is useful for some recent Gentoo and Debian distributions,
1125 which turn off plain password authentication in a misguided belief
1126 that interactive authentication is "more secure". (It's not.)
1127
1128 If the server requires multi-step authentication (which is very rare),
1129 this method will return a list of auth types permissible for the next
1130 step. Otherwise, in the normal case, an empty list is returned.
1131
1132 @param username: the username to authenticate as
1133 @type username: str
1134 @param password: the password to authenticate with
1135 @type password: str or unicode
1136 @param event: an event to trigger when the authentication attempt is
1137 complete (whether it was successful or not)
1138 @type event: threading.Event
1139 @param fallback: C{True} if an attempt at an automated "interactive"
1140 password auth should be made if the server doesn't support normal
1141 password auth
1142 @type fallback: bool
1143 @return: list of auth types permissible for the next stage of
1144 authentication (normally empty)
1145 @rtype: list
1146
1147 @raise BadAuthenticationType: if password authentication isn't
1148 allowed by the server for this user (and no event was passed in)
1149 @raise AuthenticationException: if the authentication failed (and no
1150 event was passed in)
1151 @raise SSHException: if there was a network error
1152 """
1153 if (not self.active) or (not self.initial_kex_done):
1154
1155 raise SSHException('No existing session')
1156 if event is None:
1157 my_event = threading.Event()
1158 else:
1159 my_event = event
1160 self.auth_handler = AuthHandler(self)
1161 self.auth_handler.auth_password(username, password, my_event)
1162 if event is not None:
1163
1164 return []
1165 try:
1166 return self.auth_handler.wait_for_response(my_event)
1167 except BadAuthenticationType, x:
1168
1169 if not fallback or ('keyboard-interactive' not in x.allowed_types):
1170 raise
1171 try:
1172 def handler(title, instructions, fields):
1173 if len(fields) > 1:
1174 raise SSHException('Fallback authentication failed.')
1175 if len(fields) == 0:
1176
1177
1178
1179
1180 return []
1181 return [ password ]
1182 return self.auth_interactive(username, handler)
1183 except SSHException, ignored:
1184
1185 raise x
1186 return None
1187
1189 """
1190 Authenticate to the server using a private key. The key is used to
1191 sign data from the server, so it must include the private part.
1192
1193 If an C{event} is passed in, this method will return immediately, and
1194 the event will be triggered once authentication succeeds or fails. On
1195 success, L{is_authenticated} will return C{True}. On failure, you may
1196 use L{get_exception} to get more detailed error information.
1197
1198 Since 1.1, if no event is passed, this method will block until the
1199 authentication succeeds or fails. On failure, an exception is raised.
1200 Otherwise, the method simply returns.
1201
1202 If the server requires multi-step authentication (which is very rare),
1203 this method will return a list of auth types permissible for the next
1204 step. Otherwise, in the normal case, an empty list is returned.
1205
1206 @param username: the username to authenticate as
1207 @type username: string
1208 @param key: the private key to authenticate with
1209 @type key: L{PKey <pkey.PKey>}
1210 @param event: an event to trigger when the authentication attempt is
1211 complete (whether it was successful or not)
1212 @type event: threading.Event
1213 @return: list of auth types permissible for the next stage of
1214 authentication (normally empty)
1215 @rtype: list
1216
1217 @raise BadAuthenticationType: if public-key authentication isn't
1218 allowed by the server for this user (and no event was passed in)
1219 @raise AuthenticationException: if the authentication failed (and no
1220 event was passed in)
1221 @raise SSHException: if there was a network error
1222 """
1223 if (not self.active) or (not self.initial_kex_done):
1224
1225 raise SSHException('No existing session')
1226 if event is None:
1227 my_event = threading.Event()
1228 else:
1229 my_event = event
1230 self.auth_handler = AuthHandler(self)
1231 self.auth_handler.auth_publickey(username, key, my_event)
1232 if event is not None:
1233
1234 return []
1235 return self.auth_handler.wait_for_response(my_event)
1236
1238 """
1239 Authenticate to the server interactively. A handler is used to answer
1240 arbitrary questions from the server. On many servers, this is just a
1241 dumb wrapper around PAM.
1242
1243 This method will block until the authentication succeeds or fails,
1244 peroidically calling the handler asynchronously to get answers to
1245 authentication questions. The handler may be called more than once
1246 if the server continues to ask questions.
1247
1248 The handler is expected to be a callable that will handle calls of the
1249 form: C{handler(title, instructions, prompt_list)}. The C{title} is
1250 meant to be a dialog-window title, and the C{instructions} are user
1251 instructions (both are strings). C{prompt_list} will be a list of
1252 prompts, each prompt being a tuple of C{(str, bool)}. The string is
1253 the prompt and the boolean indicates whether the user text should be
1254 echoed.
1255
1256 A sample call would thus be:
1257 C{handler('title', 'instructions', [('Password:', False)])}.
1258
1259 The handler should return a list or tuple of answers to the server's
1260 questions.
1261
1262 If the server requires multi-step authentication (which is very rare),
1263 this method will return a list of auth types permissible for the next
1264 step. Otherwise, in the normal case, an empty list is returned.
1265
1266 @param username: the username to authenticate as
1267 @type username: string
1268 @param handler: a handler for responding to server questions
1269 @type handler: callable
1270 @param submethods: a string list of desired submethods (optional)
1271 @type submethods: str
1272 @return: list of auth types permissible for the next stage of
1273 authentication (normally empty).
1274 @rtype: list
1275
1276 @raise BadAuthenticationType: if public-key authentication isn't
1277 allowed by the server for this user
1278 @raise AuthenticationException: if the authentication failed
1279 @raise SSHException: if there was a network error
1280
1281 @since: 1.5
1282 """
1283 if (not self.active) or (not self.initial_kex_done):
1284
1285 raise SSHException('No existing session')
1286 my_event = threading.Event()
1287 self.auth_handler = AuthHandler(self)
1288 self.auth_handler.auth_interactive(username, handler, my_event, submethods)
1289 return self.auth_handler.wait_for_response(my_event)
1290
1292 """
1293 Set the channel for this transport's logging. The default is
1294 C{"ssh.transport"} but it can be set to anything you want.
1295 (See the C{logging} module for more info.) SSH Channels will log
1296 to a sub-channel of the one specified.
1297
1298 @param name: new channel name for logging
1299 @type name: str
1300
1301 @since: 1.1
1302 """
1303 self.log_name = name
1304 self.logger = util.get_logger(name)
1305 self.packetizer.set_log(self.logger)
1306
1308 """
1309 Return the channel name used for this transport's logging.
1310
1311 @return: channel name.
1312 @rtype: str
1313
1314 @since: 1.2
1315 """
1316 return self.log_name
1317
1319 """
1320 Turn on/off logging a hex dump of protocol traffic at DEBUG level in
1321 the logs. Normally you would want this off (which is the default),
1322 but if you are debugging something, it may be useful.
1323
1324 @param hexdump: C{True} to log protocol traffix (in hex) to the log;
1325 C{False} otherwise.
1326 @type hexdump: bool
1327 """
1328 self.packetizer.set_hexdump(hexdump)
1329
1331 """
1332 Return C{True} if the transport is currently logging hex dumps of
1333 protocol traffic.
1334
1335 @return: C{True} if hex dumps are being logged
1336 @rtype: bool
1337
1338 @since: 1.4
1339 """
1340 return self.packetizer.get_hexdump()
1341
1343 """
1344 Turn on/off compression. This will only have an affect before starting
1345 the transport (ie before calling L{connect}, etc). By default,
1346 compression is off since it negatively affects interactive sessions.
1347
1348 @param compress: C{True} to ask the remote client/server to compress
1349 traffic; C{False} to refuse compression
1350 @type compress: bool
1351
1352 @since: 1.5.2
1353 """
1354 if compress:
1355 self._preferred_compression = ( 'zlib@openssh.com', 'zlib', 'none' )
1356 else:
1357 self._preferred_compression = ( 'none', )
1358
1360 """
1361 Return the address of the remote side of this Transport, if possible.
1362 This is effectively a wrapper around C{'getpeername'} on the underlying
1363 socket. If the socket-like object has no C{'getpeername'} method,
1364 then C{("unknown", 0)} is returned.
1365
1366 @return: the address if the remote host, if known
1367 @rtype: tuple(str, int)
1368 """
1369 gp = getattr(self.sock, 'getpeername', None)
1370 if gp is None:
1371 return ('unknown', 0)
1372 return gp()
1373
1375 self.active = False
1376 self.packetizer.close()
1377
1378
1379
1380
1381
1382 - def _log(self, level, msg, *args):
1383 if issubclass(type(msg), list):
1384 for m in msg:
1385 self.logger.log(level, m)
1386 else:
1387 self.logger.log(level, msg, *args)
1388
1390 "used by KexGex to find primes for group exchange"
1391 return self._modulus_pack
1392
1394 "you are holding the lock"
1395 chanid = self._channel_counter
1396 while self._channels.get(chanid) is not None:
1397 self._channel_counter = (self._channel_counter + 1) & 0xffffff
1398 chanid = self._channel_counter
1399 self._channel_counter = (self._channel_counter + 1) & 0xffffff
1400 return chanid
1401
1403 "used by a Channel to remove itself from the active channel list"
1404 self._channels.delete(chanid)
1405
1407 self.packetizer.send_message(data)
1408
1410 """
1411 send a message, but block if we're in key negotiation. this is used
1412 for user-initiated requests.
1413 """
1414 start = time.time()
1415 while True:
1416 self.clear_to_send.wait(0.1)
1417 if not self.active:
1418 self._log(DEBUG, 'Dropping user packet because connection is dead.')
1419 return
1420 self.clear_to_send_lock.acquire()
1421 if self.clear_to_send.isSet():
1422 break
1423 self.clear_to_send_lock.release()
1424 if time.time() > start + self.clear_to_send_timeout:
1425 raise SSHException('Key-exchange timed out waiting for key negotiation')
1426 try:
1427 self._send_message(data)
1428 finally:
1429 self.clear_to_send_lock.release()
1430
1432 "used by a kex object to set the K (root key) and H (exchange hash)"
1433 self.K = k
1434 self.H = h
1435 if self.session_id == None:
1436 self.session_id = h
1437
1439 "used by a kex object to register the next packet type it expects to see"
1440 self._expected_packet = tuple(ptypes)
1441
1449
1451 "id is 'A' - 'F' for the various keys used by ssh"
1452 m = Message()
1453 m.add_mpint(self.K)
1454 m.add_bytes(self.H)
1455 m.add_byte(id)
1456 m.add_bytes(self.session_id)
1457 out = sofar = SHA.new(str(m)).digest()
1458 while len(out) < nbytes:
1459 m = Message()
1460 m.add_mpint(self.K)
1461 m.add_bytes(self.H)
1462 m.add_bytes(sofar)
1463 digest = SHA.new(str(m)).digest()
1464 out += digest
1465 sofar += digest
1466 return out[:nbytes]
1467
1484
1486
1487 if handler is None:
1488
1489 def default_handler(channel, (src_addr, src_port)):
1490 self._queue_incoming_channel(channel)
1491 self._x11_handler = default_handler
1492 else:
1493 self._x11_handler = handler
1494
1496 self.lock.acquire()
1497 try:
1498 self.server_accepts.append(channel)
1499 self.server_accept_cv.notify()
1500 finally:
1501 self.lock.release()
1502
1504
1505
1506
1507
1508
1509
1510
1511 Random.atfork()
1512
1513
1514 _active_threads.append(self)
1515 if self.server_mode:
1516 self._log(DEBUG, 'starting thread (server mode): %s' % hex(long(id(self)) & 0xffffffffL))
1517 else:
1518 self._log(DEBUG, 'starting thread (client mode): %s' % hex(long(id(self)) & 0xffffffffL))
1519 try:
1520 self.packetizer.write_all(self.local_version + '\r\n')
1521 self._check_banner()
1522 self._send_kex_init()
1523 self._expect_packet(MSG_KEXINIT)
1524
1525 while self.active:
1526 if self.packetizer.need_rekey() and not self.in_kex:
1527 self._send_kex_init()
1528 try:
1529 ptype, m = self.packetizer.read_message()
1530 except NeedRekeyException:
1531 continue
1532 if ptype == MSG_IGNORE:
1533 continue
1534 elif ptype == MSG_DISCONNECT:
1535 self._parse_disconnect(m)
1536 self.active = False
1537 self.packetizer.close()
1538 break
1539 elif ptype == MSG_DEBUG:
1540 self._parse_debug(m)
1541 continue
1542 if len(self._expected_packet) > 0:
1543 if ptype not in self._expected_packet:
1544 raise SSHException('Expecting packet from %r, got %d' % (self._expected_packet, ptype))
1545 self._expected_packet = tuple()
1546 if (ptype >= 30) and (ptype <= 39):
1547 self.kex_engine.parse_next(ptype, m)
1548 continue
1549
1550 if ptype in self._handler_table:
1551 self._handler_table[ptype](self, m)
1552 elif ptype in self._channel_handler_table:
1553 chanid = m.get_int()
1554 chan = self._channels.get(chanid)
1555 if chan is not None:
1556 self._channel_handler_table[ptype](chan, m)
1557 elif chanid in self.channels_seen:
1558 self._log(DEBUG, 'Ignoring message for dead channel %d' % chanid)
1559 else:
1560 self._log(ERROR, 'Channel request for unknown channel %d' % chanid)
1561 self.active = False
1562 self.packetizer.close()
1563 elif (self.auth_handler is not None) and (ptype in self.auth_handler._handler_table):
1564 self.auth_handler._handler_table[ptype](self.auth_handler, m)
1565 else:
1566 self._log(WARNING, 'Oops, unhandled type %d' % ptype)
1567 msg = Message()
1568 msg.add_byte(chr(MSG_UNIMPLEMENTED))
1569 msg.add_int(m.seqno)
1570 self._send_message(msg)
1571 except SSHException, e:
1572 self._log(ERROR, 'Exception: ' + str(e))
1573 self._log(ERROR, util.tb_strings())
1574 self.saved_exception = e
1575 except EOFError, e:
1576 self._log(DEBUG, 'EOF in transport thread')
1577
1578 self.saved_exception = e
1579 except socket.error, e:
1580 if type(e.args) is tuple:
1581 emsg = '%s (%d)' % (e.args[1], e.args[0])
1582 else:
1583 emsg = e.args
1584 self._log(ERROR, 'Socket exception: ' + emsg)
1585 self.saved_exception = e
1586 except Exception, e:
1587 self._log(ERROR, 'Unknown exception: ' + str(e))
1588 self._log(ERROR, util.tb_strings())
1589 self.saved_exception = e
1590 _active_threads.remove(self)
1591 for chan in self._channels.values():
1592 chan._unlink()
1593 if self.active:
1594 self.active = False
1595 self.packetizer.close()
1596 if self.completion_event != None:
1597 self.completion_event.set()
1598 if self.auth_handler is not None:
1599 self.auth_handler.abort()
1600 for event in self.channel_events.values():
1601 event.set()
1602 try:
1603 self.lock.acquire()
1604 self.server_accept_cv.notify()
1605 finally:
1606 self.lock.release()
1607 self.sock.close()
1608
1609
1610
1611
1612
1614
1615 self.clear_to_send_lock.acquire()
1616 try:
1617 self.clear_to_send.clear()
1618 finally:
1619 self.clear_to_send_lock.release()
1620 if self.local_kex_init == None:
1621
1622 self._send_kex_init()
1623 self._parse_kex_init(m)
1624 self.kex_engine.start_kex()
1625
1627
1628 for i in range(100):
1629
1630
1631 if i == 0:
1632 timeout = self.banner_timeout
1633 else:
1634 timeout = 2
1635 try:
1636 buf = self.packetizer.readline(timeout)
1637 except Exception, x:
1638 raise SSHException('Error reading SSH protocol banner' + str(x))
1639 if buf[:4] == 'SSH-':
1640 break
1641 self._log(DEBUG, 'Banner: ' + buf)
1642 if buf[:4] != 'SSH-':
1643 raise SSHException('Indecipherable protocol version "' + buf + '"')
1644
1645 self.remote_version = buf
1646
1647 comment = ''
1648 i = string.find(buf, ' ')
1649 if i >= 0:
1650 comment = buf[i+1:]
1651 buf = buf[:i]
1652
1653 segs = buf.split('-', 2)
1654 if len(segs) < 3:
1655 raise SSHException('Invalid SSH banner')
1656 version = segs[1]
1657 client = segs[2]
1658 if version != '1.99' and version != '2.0':
1659 raise SSHException('Incompatible version (%s instead of 2.0)' % (version,))
1660 self._log(INFO, 'Connected (version %s, client %s)' % (version, client))
1661
1702
1704 cookie = m.get_bytes(16)
1705 kex_algo_list = m.get_list()
1706 server_key_algo_list = m.get_list()
1707 client_encrypt_algo_list = m.get_list()
1708 server_encrypt_algo_list = m.get_list()
1709 client_mac_algo_list = m.get_list()
1710 server_mac_algo_list = m.get_list()
1711 client_compress_algo_list = m.get_list()
1712 server_compress_algo_list = m.get_list()
1713 client_lang_list = m.get_list()
1714 server_lang_list = m.get_list()
1715 kex_follows = m.get_boolean()
1716 unused = m.get_int()
1717
1718 self._log(DEBUG, 'kex algos:' + str(kex_algo_list) + ' server key:' + str(server_key_algo_list) + \
1719 ' client encrypt:' + str(client_encrypt_algo_list) + \
1720 ' server encrypt:' + str(server_encrypt_algo_list) + \
1721 ' client mac:' + str(client_mac_algo_list) + \
1722 ' server mac:' + str(server_mac_algo_list) + \
1723 ' client compress:' + str(client_compress_algo_list) + \
1724 ' server compress:' + str(server_compress_algo_list) + \
1725 ' client lang:' + str(client_lang_list) + \
1726 ' server lang:' + str(server_lang_list) + \
1727 ' kex follows?' + str(kex_follows))
1728
1729
1730
1731 if self.server_mode:
1732 agreed_kex = filter(self._preferred_kex.__contains__, kex_algo_list)
1733 else:
1734 agreed_kex = filter(kex_algo_list.__contains__, self._preferred_kex)
1735 if len(agreed_kex) == 0:
1736 raise SSHException('Incompatible ssh peer (no acceptable kex algorithm)')
1737 self.kex_engine = self._kex_info[agreed_kex[0]](self)
1738
1739 if self.server_mode:
1740 available_server_keys = filter(self.server_key_dict.keys().__contains__,
1741 self._preferred_keys)
1742 agreed_keys = filter(available_server_keys.__contains__, server_key_algo_list)
1743 else:
1744 agreed_keys = filter(server_key_algo_list.__contains__, self._preferred_keys)
1745 if len(agreed_keys) == 0:
1746 raise SSHException('Incompatible ssh peer (no acceptable host key)')
1747 self.host_key_type = agreed_keys[0]
1748 if self.server_mode and (self.get_server_key() is None):
1749 raise SSHException('Incompatible ssh peer (can\'t match requested host key type)')
1750
1751 if self.server_mode:
1752 agreed_local_ciphers = filter(self._preferred_ciphers.__contains__,
1753 server_encrypt_algo_list)
1754 agreed_remote_ciphers = filter(self._preferred_ciphers.__contains__,
1755 client_encrypt_algo_list)
1756 else:
1757 agreed_local_ciphers = filter(client_encrypt_algo_list.__contains__,
1758 self._preferred_ciphers)
1759 agreed_remote_ciphers = filter(server_encrypt_algo_list.__contains__,
1760 self._preferred_ciphers)
1761 if (len(agreed_local_ciphers) == 0) or (len(agreed_remote_ciphers) == 0):
1762 raise SSHException('Incompatible ssh server (no acceptable ciphers)')
1763 self.local_cipher = agreed_local_ciphers[0]
1764 self.remote_cipher = agreed_remote_ciphers[0]
1765 self._log(DEBUG, 'Ciphers agreed: local=%s, remote=%s' % (self.local_cipher, self.remote_cipher))
1766
1767 if self.server_mode:
1768 agreed_remote_macs = filter(self._preferred_macs.__contains__, client_mac_algo_list)
1769 agreed_local_macs = filter(self._preferred_macs.__contains__, server_mac_algo_list)
1770 else:
1771 agreed_local_macs = filter(client_mac_algo_list.__contains__, self._preferred_macs)
1772 agreed_remote_macs = filter(server_mac_algo_list.__contains__, self._preferred_macs)
1773 if (len(agreed_local_macs) == 0) or (len(agreed_remote_macs) == 0):
1774 raise SSHException('Incompatible ssh server (no acceptable macs)')
1775 self.local_mac = agreed_local_macs[0]
1776 self.remote_mac = agreed_remote_macs[0]
1777
1778 if self.server_mode:
1779 agreed_remote_compression = filter(self._preferred_compression.__contains__, client_compress_algo_list)
1780 agreed_local_compression = filter(self._preferred_compression.__contains__, server_compress_algo_list)
1781 else:
1782 agreed_local_compression = filter(client_compress_algo_list.__contains__, self._preferred_compression)
1783 agreed_remote_compression = filter(server_compress_algo_list.__contains__, self._preferred_compression)
1784 if (len(agreed_local_compression) == 0) or (len(agreed_remote_compression) == 0):
1785 raise SSHException('Incompatible ssh server (no acceptable compression) %r %r %r' % (agreed_local_compression, agreed_remote_compression, self._preferred_compression))
1786 self.local_compression = agreed_local_compression[0]
1787 self.remote_compression = agreed_remote_compression[0]
1788
1789 self._log(DEBUG, 'using kex %s; server key type %s; cipher: local %s, remote %s; mac: local %s, remote %s; compression: local %s, remote %s' %
1790 (agreed_kex[0], self.host_key_type, self.local_cipher, self.remote_cipher, self.local_mac,
1791 self.remote_mac, self.local_compression, self.remote_compression))
1792
1793
1794
1795
1796
1797
1798 self.remote_kex_init = chr(MSG_KEXINIT) + m.get_so_far()
1799
1801 "switch on newly negotiated encryption parameters for inbound traffic"
1802 block_size = self._cipher_info[self.remote_cipher]['block-size']
1803 if self.server_mode:
1804 IV_in = self._compute_key('A', block_size)
1805 key_in = self._compute_key('C', self._cipher_info[self.remote_cipher]['key-size'])
1806 else:
1807 IV_in = self._compute_key('B', block_size)
1808 key_in = self._compute_key('D', self._cipher_info[self.remote_cipher]['key-size'])
1809 engine = self._get_cipher(self.remote_cipher, key_in, IV_in)
1810 mac_size = self._mac_info[self.remote_mac]['size']
1811 mac_engine = self._mac_info[self.remote_mac]['class']
1812
1813
1814 if self.server_mode:
1815 mac_key = self._compute_key('E', mac_engine.digest_size)
1816 else:
1817 mac_key = self._compute_key('F', mac_engine.digest_size)
1818 self.packetizer.set_inbound_cipher(engine, block_size, mac_engine, mac_size, mac_key)
1819 compress_in = self._compression_info[self.remote_compression][1]
1820 if (compress_in is not None) and ((self.remote_compression != 'zlib@openssh.com') or self.authenticated):
1821 self._log(DEBUG, 'Switching on inbound compression ...')
1822 self.packetizer.set_inbound_compressor(compress_in())
1823
1825 "switch on newly negotiated encryption parameters for outbound traffic"
1826 m = Message()
1827 m.add_byte(chr(MSG_NEWKEYS))
1828 self._send_message(m)
1829 block_size = self._cipher_info[self.local_cipher]['block-size']
1830 if self.server_mode:
1831 IV_out = self._compute_key('B', block_size)
1832 key_out = self._compute_key('D', self._cipher_info[self.local_cipher]['key-size'])
1833 else:
1834 IV_out = self._compute_key('A', block_size)
1835 key_out = self._compute_key('C', self._cipher_info[self.local_cipher]['key-size'])
1836 engine = self._get_cipher(self.local_cipher, key_out, IV_out)
1837 mac_size = self._mac_info[self.local_mac]['size']
1838 mac_engine = self._mac_info[self.local_mac]['class']
1839
1840
1841 if self.server_mode:
1842 mac_key = self._compute_key('F', mac_engine.digest_size)
1843 else:
1844 mac_key = self._compute_key('E', mac_engine.digest_size)
1845 self.packetizer.set_outbound_cipher(engine, block_size, mac_engine, mac_size, mac_key)
1846 compress_out = self._compression_info[self.local_compression][0]
1847 if (compress_out is not None) and ((self.local_compression != 'zlib@openssh.com') or self.authenticated):
1848 self._log(DEBUG, 'Switching on outbound compression ...')
1849 self.packetizer.set_outbound_compressor(compress_out())
1850 if not self.packetizer.need_rekey():
1851 self.in_kex = False
1852
1853 self._expect_packet(MSG_NEWKEYS)
1854
1856 self.authenticated = True
1857
1858 if self.local_compression == 'zlib@openssh.com':
1859 compress_out = self._compression_info[self.local_compression][0]
1860 self._log(DEBUG, 'Switching on outbound compression ...')
1861 self.packetizer.set_outbound_compressor(compress_out())
1862 if self.remote_compression == 'zlib@openssh.com':
1863 compress_in = self._compression_info[self.remote_compression][1]
1864 self._log(DEBUG, 'Switching on inbound compression ...')
1865 self.packetizer.set_inbound_compressor(compress_in())
1866
1868 self._log(DEBUG, 'Switch to new keys ...')
1869 self._activate_inbound()
1870
1871 self.local_kex_init = self.remote_kex_init = None
1872 self.K = None
1873 self.kex_engine = None
1874 if self.server_mode and (self.auth_handler is None):
1875
1876 self.auth_handler = AuthHandler(self)
1877 if not self.initial_kex_done:
1878
1879 self.initial_kex_done = True
1880
1881 if self.completion_event != None:
1882 self.completion_event.set()
1883
1884 if not self.packetizer.need_rekey():
1885 self.in_kex = False
1886 self.clear_to_send_lock.acquire()
1887 try:
1888 self.clear_to_send.set()
1889 finally:
1890 self.clear_to_send_lock.release()
1891 return
1892
1894 code = m.get_int()
1895 desc = m.get_string()
1896 self._log(INFO, 'Disconnect (code %d): %s' % (code, desc))
1897
1930
1932 self._log(DEBUG, 'Global request successful.')
1933 self.global_response = m
1934 if self.completion_event is not None:
1935 self.completion_event.set()
1936
1938 self._log(DEBUG, 'Global request denied.')
1939 self.global_response = None
1940 if self.completion_event is not None:
1941 self.completion_event.set()
1942
1944 chanid = m.get_int()
1945 server_chanid = m.get_int()
1946 server_window_size = m.get_int()
1947 server_max_packet_size = m.get_int()
1948 chan = self._channels.get(chanid)
1949 if chan is None:
1950 self._log(WARNING, 'Success for unrequested channel! [??]')
1951 return
1952 self.lock.acquire()
1953 try:
1954 chan._set_remote_channel(server_chanid, server_window_size, server_max_packet_size)
1955 self._log(INFO, 'Secsh channel %d opened.' % chanid)
1956 if chanid in self.channel_events:
1957 self.channel_events[chanid].set()
1958 del self.channel_events[chanid]
1959 finally:
1960 self.lock.release()
1961 return
1962
1964 chanid = m.get_int()
1965 reason = m.get_int()
1966 reason_str = m.get_string()
1967 lang = m.get_string()
1968 reason_text = CONNECTION_FAILED_CODE.get(reason, '(unknown code)')
1969 self._log(INFO, 'Secsh channel %d open FAILED: %s: %s' % (chanid, reason_str, reason_text))
1970 self.lock.acquire()
1971 try:
1972 self.saved_exception = ChannelException(reason, reason_text)
1973 if chanid in self.channel_events:
1974 self._channels.delete(chanid)
1975 if chanid in self.channel_events:
1976 self.channel_events[chanid].set()
1977 del self.channel_events[chanid]
1978 finally:
1979 self.lock.release()
1980 return
1981
1983 kind = m.get_string()
1984 chanid = m.get_int()
1985 initial_window_size = m.get_int()
1986 max_packet_size = m.get_int()
1987 reject = False
1988 if (kind == 'x11') and (self._x11_handler is not None):
1989 origin_addr = m.get_string()
1990 origin_port = m.get_int()
1991 self._log(DEBUG, 'Incoming x11 connection from %s:%d' % (origin_addr, origin_port))
1992 self.lock.acquire()
1993 try:
1994 my_chanid = self._next_channel()
1995 finally:
1996 self.lock.release()
1997 elif (kind == 'forwarded-tcpip') and (self._tcp_handler is not None):
1998 server_addr = m.get_string()
1999 server_port = m.get_int()
2000 origin_addr = m.get_string()
2001 origin_port = m.get_int()
2002 self._log(DEBUG, 'Incoming tcp forwarded connection from %s:%d' % (origin_addr, origin_port))
2003 self.lock.acquire()
2004 try:
2005 my_chanid = self._next_channel()
2006 finally:
2007 self.lock.release()
2008 elif not self.server_mode:
2009 self._log(DEBUG, 'Rejecting "%s" channel request from server.' % kind)
2010 reject = True
2011 reason = OPEN_FAILED_ADMINISTRATIVELY_PROHIBITED
2012 else:
2013 self.lock.acquire()
2014 try:
2015 my_chanid = self._next_channel()
2016 finally:
2017 self.lock.release()
2018 if kind == 'direct-tcpip':
2019
2020 dest_addr = m.get_string()
2021 dest_port = m.get_int()
2022 origin_addr = m.get_string()
2023 origin_port = m.get_int()
2024 reason = self.server_object.check_channel_direct_tcpip_request(
2025 my_chanid, (origin_addr, origin_port),
2026 (dest_addr, dest_port))
2027 else:
2028 reason = self.server_object.check_channel_request(kind, my_chanid)
2029 if reason != OPEN_SUCCEEDED:
2030 self._log(DEBUG, 'Rejecting "%s" channel request from client.' % kind)
2031 reject = True
2032 if reject:
2033 msg = Message()
2034 msg.add_byte(chr(MSG_CHANNEL_OPEN_FAILURE))
2035 msg.add_int(chanid)
2036 msg.add_int(reason)
2037 msg.add_string('')
2038 msg.add_string('en')
2039 self._send_message(msg)
2040 return
2041
2042 chan = Channel(my_chanid)
2043 self.lock.acquire()
2044 try:
2045 self._channels.put(my_chanid, chan)
2046 self.channels_seen[my_chanid] = True
2047 chan._set_transport(self)
2048 chan._set_window(self.window_size, self.max_packet_size)
2049 chan._set_remote_channel(chanid, initial_window_size, max_packet_size)
2050 finally:
2051 self.lock.release()
2052 m = Message()
2053 m.add_byte(chr(MSG_CHANNEL_OPEN_SUCCESS))
2054 m.add_int(chanid)
2055 m.add_int(my_chanid)
2056 m.add_int(self.window_size)
2057 m.add_int(self.max_packet_size)
2058 self._send_message(m)
2059 self._log(INFO, 'Secsh channel %d (%s) opened.', my_chanid, kind)
2060 if kind == 'x11':
2061 self._x11_handler(chan, (origin_addr, origin_port))
2062 elif kind == 'forwarded-tcpip':
2063 chan.origin_addr = (origin_addr, origin_port)
2064 self._tcp_handler(chan, (origin_addr, origin_port), (server_addr, server_port))
2065 else:
2066 self._queue_incoming_channel(chan)
2067
2073
2075 try:
2076 self.lock.acquire()
2077 if name not in self.subsystem_table:
2078 return (None, [], {})
2079 return self.subsystem_table[name]
2080 finally:
2081 self.lock.release()
2082
2083 _handler_table = {
2084 MSG_NEWKEYS: _parse_newkeys,
2085 MSG_GLOBAL_REQUEST: _parse_global_request,
2086 MSG_REQUEST_SUCCESS: _parse_request_success,
2087 MSG_REQUEST_FAILURE: _parse_request_failure,
2088 MSG_CHANNEL_OPEN_SUCCESS: _parse_channel_open_success,
2089 MSG_CHANNEL_OPEN_FAILURE: _parse_channel_open_failure,
2090 MSG_CHANNEL_OPEN: _parse_channel_open,
2091 MSG_KEXINIT: _negotiate_keys,
2092 }
2093
2094 _channel_handler_table = {
2095 MSG_CHANNEL_SUCCESS: Channel._request_success,
2096 MSG_CHANNEL_FAILURE: Channel._request_failed,
2097 MSG_CHANNEL_DATA: Channel._feed,
2098 MSG_CHANNEL_EXTENDED_DATA: Channel._feed_extended,
2099 MSG_CHANNEL_WINDOW_ADJUST: Channel._window_adjust,
2100 MSG_CHANNEL_REQUEST: Channel._handle_request,
2101 MSG_CHANNEL_EOF: Channel._handle_eof,
2102 MSG_CHANNEL_CLOSE: Channel._handle_close,
2103 }
2104