/usr/share/pyshared/x2go/sshproxy.py is in python-x2go 0.1.1.8-0ubuntu1.
This file is owned by root:root, with mode 0o644.
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# Copyright (C) 2010-2011 by Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
#
# Python X2go is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# Python X2go is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the
# Free Software Foundation, Inc.,
# 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
"""\
L{X2goSSHProxy} class - providing a forwarding tunnel for connecting to servers behind firewalls.
"""
__NAME__ = 'x2gosshproxy-pylib'
# modules
import gevent
import os
import copy
import paramiko
import threading
import socket
import string
import random
# Python X2go modules
import x2go.forward as forward
import x2go.checkhosts as checkhosts
import x2go.log as log
import x2go.utils as utils
from x2go.x2go_exceptions import *
from x2go.defaults import CURRENT_LOCAL_USER as _CURRENT_LOCAL_USER
from x2go.defaults import LOCAL_HOME as _LOCAL_HOME
from x2go.defaults import X2GO_SSH_ROOTDIR as _X2GO_SSH_ROOTDIR
from monkey_patch_paramiko import monkey_patch_paramiko
monkey_patch_paramiko()
class X2goSSHProxy(paramiko.SSHClient, threading.Thread):
"""\
X2goSSHProxy can be used to proxy X2go connections through a firewall via SSH.
"""
fw_tunnel = None
def __init__(self, hostname=None, port=22, username=None, password=None, key_filename=None,
local_host='localhost', local_port=22022, remote_host='localhost', remote_port=22,
known_hosts=None, add_to_known_hosts=False, pkey=None,
sshproxy_host=None, sshproxy_port=22, sshproxy_user=None,
sshproxy_password=None, sshproxy_key_filename=None, sshproxy_pkey=None,
sshproxy_tunnel=None,
ssh_rootdir=os.path.join(_LOCAL_HOME, _X2GO_SSH_ROOTDIR),
session_instance=None,
logger=None, loglevel=log.loglevel_DEFAULT, ):
"""\
Initialize an X2goSSHProxy instance. Use an instance of this class to tunnel X2go requests through
a proxying SSH server (i.e. to subLANs that are separated by firewalls or to private IP subLANs that
are NATted behind routers).
@param username: login user name to be used on the SSH proxy host
@type username: C{str}
@param password: user's password on the SSH proxy host
@type password: C{str}
@param key_filename: name of a SSH private key file
@type key_filename: C{str}
@param pkey: a private DSA/RSA key object (as provided by Paramiko/SSH)
@type pkey: C{RSA/DSA key instance}
@param local_host: bind SSH tunnel to the C{local_host} IP socket address (default: localhost)
@type local_host: C{str}
@param local_port: IP socket port to bind the SSH tunnel to (default; 22022)
@type local_port: C{int}
@param remote_host: remote endpoint of the SSH proxying/forwarding tunnel (default: localhost)
@type remote_host: C{str}
@param remote_port: remote endpoint's IP socket port for listening SSH daemon (default: 22)
@type remote_port: C{int}
@param known_hosts: full path to a custom C{known_hosts} file
@type known_hosts: C{str}
@param add_to_known_hosts: automatically add host keys of unknown SSH hosts to the C{known_hosts} file
@type add_to_known_hosts: C{bool}
@param hostname: alias for C{local_host}
@type hostname: C{str}
@param port: alias for C{local_port}
@type port: C{int}
@param sshproxy_host: alias for C{remote_host}
@type sshproxy_host: C{str}
@param sshproxy_port: alias for C{remote_port}
@type sshproxy_port: C{int}
@param sshproxy_user: alias for C{username}
@type sshproxy_user: C{str}
@param sshproxy_password: alias for C{password}
@type sshproxy_password: C{str}
@param sshproxy_key_filename: alias for C{key_filename}
@type sshproxy_key_filename: C{str}
@param sshproxy_pkey: alias for C{pkey}
@type sshproxy_pkey: C{RSA/DSA key instance} (Paramiko)
@param sshproxy_tunnel: a string of the format <local_host>:<local_port>:<remote_host>:<remote_port>
which will override---if used---the options: C{local_host}, C{local_port}, C{remote_host} and C{remote_port}
@type sshproxy_tunnel: C{str}
@param ssh_rootdir: local user's SSH base directory (default: ~/.ssh)
@type ssh_rootdir: C{str}
@param session_instance: the L{X2goSession} instance that builds up this SSH proxying tunnel
@type session_instance: L{X2goSession} instance
@param logger: you can pass an L{X2goLogger} object to the
L{X2goSSHProxy} constructor
@type logger: L{X2goLogger} instance
@param loglevel: if no L{X2goLogger} object has been supplied a new one will be
constructed with the given loglevel
@type loglevel: int
"""
if logger is None:
self.logger = log.X2goLogger(loglevel=loglevel)
else:
self.logger = copy.deepcopy(logger)
self.logger.tag = __NAME__
self.hostname, self.port, self.username = hostname, port, username
# translate between X2goSession options and paramiko.SSHCLient.connect() options
if sshproxy_host:
if sshproxy_host.find(':'):
self.hostname = sshproxy_host.split(':')[0]
try: self.port = int(sshproxy_host.split(':')[1])
except IndexError: pass
else:
self.hostname = sshproxy_host
if sshproxy_user: self.username = sshproxy_user
if sshproxy_password: password = sshproxy_password
if sshproxy_key_filename: key_filename = sshproxy_key_filename
if sshproxy_pkey: pkey = sshproxy_pkey
if sshproxy_tunnel:
self.local_host, self.local_port, self.remote_host, self.remote_port = sshproxy_tunnel.split(':')
self.local_port = int(self.local_port)
self.remote_port = int(self.remote_port)
else:
self.local_host = local_host
self.local_port = int(local_port)
self.remote_host = remote_host
self.remote_port = int(remote_port)
# allow more trailing whitespace tolerance in hostnames
self.hostname = self.hostname.strip()
self.local_host = self.local_host.strip()
self.remote_host = self.remote_host.strip()
# enforce IPv4 for localhost addresses!!!
_hostname = self.hostname
if _hostname in ('localhost', 'localhost.localdomain'):
_hostname = '127.0.0.1'
if self.local_host in ('localhost', 'localhost.localdomain'):
self.local_host = '127.0.0.1'
if self.remote_host in ('localhost', 'localhost.localdomain'):
self.remote_host = '127.0.0.1'
if username is None:
username = _CURRENT_LOCAL_USER
self._keepalive = True
self.ssh_rootdir = ssh_rootdir
paramiko.SSHClient.__init__(self)
self.known_hosts = known_hosts
if self.known_hosts:
utils.touch_file(self.known_hosts)
self.load_host_keys(self.known_hosts)
if not add_to_known_hosts and session_instance:
self.set_missing_host_key_policy(checkhosts.X2goInteractiveAddPolicy(caller=self, session_instance=session_instance))
if add_to_known_hosts:
self.set_missing_host_key_policy(paramiko.AutoAddPolicy())
try:
if (key_filename and os.path.exists(os.path.normpath(key_filename))) or pkey:
try:
self.connect(_hostname, port=self.port,
username=self.username,
key_filename=key_filename,
pkey=pkey,
look_for_keys=False,
allow_agent=False,
)
except AuthenticationException, e:
self.close()
raise X2goSSHProxyAuthenticationException('pubkey auth mechanisms both failed')
except:
self.close()
raise
# if there is not private key, we will use the given password, if any
else:
# create a random password if password is empty to trigger host key validity check
if not password:
password = "".join([random.choice(string.letters+string.digits) for x in range(1, 20)])
try:
self.connect(_hostname, port=self.port,
username=self.username,
password=password,
look_for_keys=False,
allow_agent=False,
)
except AuthenticationException:
self.close()
raise X2goSSHProxyAuthenticationException('interactive auth mechanisms failed')
except:
self.close()
raise
except paramiko.SSHException, e:
self.close()
raise X2goSSHProxyException(str(e))
except:
self.close()
raise
self.set_missing_host_key_policy(paramiko.RejectPolicy())
threading.Thread.__init__(self)
self.daemon = True
def check_host(self):
"""\
Wraps around a Paramiko/SSH host key check.
"""
# hostname rewrite for localhost, force to IPv4
_hostname = self.hostname
# force into IPv4 for localhost connections
if _hostname in ('localhost', 'localhost.localdomain'):
_hostname = '127.0.0.1'
_valid = False
(_valid, _hostname, _port, _fingerprint, _fingerprint_type) = checkhosts.check_ssh_host_key(self, _hostname, port=self.port)
if not _valid and self.session_instance:
_valid = self.session_instance.HOOK_check_host_dialog(_hostname, _port, fingerprint=_fingerprint, fingerprint_type=_fingerprint_type)
return _valid
def run(self):
"""\
Start the SSH proxying tunnel...
"""
if self.get_transport() is not None and self.get_transport().is_authenticated():
self.local_port = utils.detect_unused_port(bind_address=self.local_host, preferred_port=self.local_port)
self.fw_tunnel = forward.start_forward_tunnel(local_host=self.local_host,
local_port=self.local_port,
remote_host=self.remote_host,
remote_port=self.remote_port,
ssh_transport=self.get_transport(),
logger=self.logger, )
self.logger('SSH proxy tunnel via [%s]:%s has been set up' % (self.hostname, self.port), loglevel=log.loglevel_NOTICE)
self.logger('SSH proxy tunnel startpoint is [%s]:%s, endpoint is [%s]:%s' % (self.local_host, self.local_port, self.remote_host, self.remote_port), loglevel=log.loglevel_NOTICE)
while self._keepalive:
gevent.sleep(.1)
else:
raise X2goSSHProxyException('SSH proxy connection could not retrieve an SSH transport')
def get_local_proxy_port(self):
"""\
Retrieve the local IP socket port this SSH proxying tunnel is (about to) bind/bound to.
@return: local IP socket port
@rtype: C{int}
"""
return self.local_port
def stop_thread(self):
"""\
Tear down the SSH proxying tunnel.
"""
if self.fw_tunnel is not None and self.fw_tunnel.is_active:
self.logger('taking down SSH proxy tunnel via [%s]:%s' % (self.hostname, self.port), loglevel=log.loglevel_NOTICE)
try: forward.stop_forward_tunnel(self.fw_tunnel)
except: pass
self.fw_tunnel = None
self._keepalive = False
if self.get_transport() is not None:
self.logger('closing SSH proxy connection to [%s]:%s' % (self.hostname, self.port), loglevel=log.loglevel_NOTICE)
self.close()
self.password = self.sshproxy_password = None
def __del__(self):
"""\
Class desctructor.
"""
self.stop_thread()
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