/usr/share/pyshared/x2go/sshproxy.py is in python-x2go 0.4.0.8-1.
This file is owned by root:root, with mode 0o644.
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# Copyright (C) 2010-2013 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 Affero 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero 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 string
import random
# Python X2Go modules
import forward
import checkhosts
import log
import utils
import x2go_exceptions
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
import x2go._paramiko
x2go._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, force_password_auth=False, 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, look_for_keys=False, allow_agent=False,
sshproxy_host=None, sshproxy_port=22, sshproxy_user=None,
sshproxy_password=None, sshproxy_force_password_auth=False, sshproxy_key_filename=None, sshproxy_pkey=None,
sshproxy_look_for_keys=False, sshproxy_allow_agent=False,
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, with private key authentication it will be
used to unlock the key (if needed)
@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 force_password_auth: enforce password authentication even if a key(file) is present
@type force_password_auth: C{bool}
@param look_for_keys: look for key files with standard names and try those if any can be found
@type look_for_keys: C{bool}
@param allow_agent: try authentication via a locally available SSH agent
@type allow_agent: C{bool}
@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{hostname}
@type sshproxy_host: C{str}
@param sshproxy_port: alias for C{post}
@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_force_password_auth: alias for C{force_password_auth}
@type sshproxy_force_password_auth: C{bool}
@param sshproxy_look_for_keys: alias for C{look_for_keys}
@type sshproxy_look_for_keys: C{bool}
@param sshproxy_allow_agent: alias for C{allow_agent}
@type sshproxy_allow_agent: C{bool}
@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
@raise X2GoSSHProxyAuthenticationException: if the SSH proxy caused a C{paramiko.AuthenticationException}
@raise X2GoSSHProxyException: if the SSH proxy caused a C{paramiko.SSHException}
"""
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
if sshproxy_port: self.port = sshproxy_port
# translate between X2GoSession options and paramiko.SSHCLient.connect() options
# if <hostname>:<port> is used for sshproxy_host, then this <port> is used
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_force_password_auth: force_password_auth = sshproxy_force_password_auth
if sshproxy_key_filename: key_filename = sshproxy_key_filename
if sshproxy_pkey: pkey = sshproxy_pkey
if sshproxy_look_for_keys: look_for_keys = sshproxy_look_for_keys
if sshproxy_allow_agent: allow_agent = sshproxy_allow_agent
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.session_instance = session_instance
self.client_instance = None
if self.session_instance is not None:
self.client_instance = self.session_instance.get_client_instance()
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 or pkey or look_for_keys or allow_agent or (password and force_password_auth):
try:
if password and force_password_auth:
self.connect(_hostname, port=self.port,
username=self.username,
password=password,
key_filename=None,
pkey=None,
look_for_keys=False,
allow_agent=False,
)
elif (key_filename and os.path.exists(os.path.normpath(key_filename))) or pkey:
self.connect(_hostname, port=self.port,
username=self.username,
key_filename=key_filename,
pkey=pkey,
look_for_keys=look_for_keys,
allow_agent=allow_agent,
)
else:
self.connect(_hostname, port=self.port,
username=self.username,
look_for_keys=look_for_keys,
allow_agent=allow_agent,
)
except x2go_exceptions.AuthenticationException, e:
self.close()
raise x2go_exceptions.X2GoSSHProxyAuthenticationException('pubkey auth mechanisms both failed')
except x2go_exceptions.SSHException, e:
self.close()
raise x2go_exceptions.X2GoSSHProxyAuthenticationException('interactive authentication required')
except:
raise
# since Paramiko 1.7.7.1 there is compression available, let's use it if present...
t = self.get_transport()
if x2go._paramiko.PARAMIKO_FEATURE['use-compression']:
t.use_compression(compress=True)
# if there is no 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 x2go_exceptions.AuthenticationException:
self.close()
raise x2go_exceptions.X2GoSSHProxyAuthenticationException('interactive auth mechanisms failed')
except:
self.close()
raise
except (x2go_exceptions.SSHException, IOError), e:
self.close()
raise x2go_exceptions.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 = 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(self.remote_host, self.remote_port, fingerprint=_fingerprint, fingerprint_type=_fingerprint_type)
return _valid
def run(self):
"""\
Start the SSH proxying tunnel...
@raise X2GoSSHProxyException: if the SSH proxy could not retrieve an SSH transport for proxying a X2Go server-client connection
"""
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)
if self.client_instance is not None:
_profile_id = self.session_instance.get_profile_id()
if self.client_instance.session_profiles.has_profile(_profile_id):
self.client_instance.session_profiles.update_value(_profile_id,
'sshproxytunnel',
'%s:%s:%s:%s' % (self.local_host, self.local_port, self.remote_host, self.remote_port)
)
self.client_instance.session_profiles.write_user_config = True
self.client_instance.session_profiles.write()
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 x2go_exceptions.X2GoSSHProxyException('SSH proxy connection could not retrieve an SSH transport')
def get_local_proxy_host(self):
"""\
Retrieve the local IP socket address this SSH proxying tunnel is (about to) bind/bound to.
@return: local IP socket address
@rtype: C{str}
"""
return self.local_host
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 get_remote_host(self):
"""\
Retrieve the remote IP socket address at the remote end of the SSH proxying tunnel.
@return: remote IP socket address
@rtype: C{str}
"""
return self.remote_host
def get_remote_port(self):
"""\
Retrieve the remote IP socket port of the target system's SSH daemon.
@return: remote SSH port
@rtype: C{int}
"""
return self.remote_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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