211 lines
7.0 KiB
Python
Executable File
211 lines
7.0 KiB
Python
Executable File
#!/usr/bin/python
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"""
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Sample script showing how to do local port forwarding over paramiko.
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This script connects to the requested SSH server and sets up local port
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forwarding (the openssh -L option) from a local port through a tunneled
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connection to a destination reachable from the SSH server machine.
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It uses SocketServer and select, so may not work on Windows.
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"""
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import sys
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import os
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import socket
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import select
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import SocketServer
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import getpass
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import base64
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from optparse import OptionParser
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import paramiko
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DEFAULT_PORT = 4000
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SSH_PORT = 22
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VERBOSE = True
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READPASS = False
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class ForwardServer (SocketServer.ThreadingTCPServer):
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daemon_threads = True
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allow_reuse_address = True
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class Handler (SocketServer.BaseRequestHandler):
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def handle(self):
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try:
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chan = self.ssh_transport.open_channel('direct-tcpip',
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(self.chain_host, self.chain_port),
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self.request.getpeername())
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except Exception, e:
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verbose('Incoming request to %s:%d failed: %s' % (self.chain_host,
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self.chain_port,
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repr(e)))
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return
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verbose('Connected! Tunnel open.')
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while True:
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r, w, x = select.select([self.request, chan], [], [])
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if self.request in r:
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data = self.request.recv(1024)
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if len(data) == 0:
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break
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chan.send(data)
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if chan in r:
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data = chan.recv(1024)
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if len(data) == 0:
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break
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self.request.send(data)
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chan.close()
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self.request.close()
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verbose('Tunnel closed.')
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def forward_tunnel(local_port, remote_host, remote_port, transport):
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# this is a little convoluted, but lets me configure things for the Handler
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# object. (SocketServer doesn't give Handlers any way to access the outer
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# server normally.)
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class SubHander (Handler):
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chain_host = remote_host
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chain_port = remote_port
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ssh_transport = transport
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ForwardServer(('', local_port), SubHander).serve_forever()
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def load_host_keys():
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filename = os.path.expanduser('~/.ssh/known_hosts')
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keys = {}
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try:
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f = open(filename, 'r')
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except Exception, e:
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print '*** Unable to open host keys file (%s)' % filename
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return
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for line in f:
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keylist = line.split(' ')
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if len(keylist) != 3:
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continue
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hostlist, keytype, key = keylist
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hosts = hostlist.split(',')
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for host in hosts:
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if not keys.has_key(host):
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keys[host] = {}
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keys[host][keytype] = base64.decodestring(key)
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f.close()
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return keys
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def find_default_key_file():
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filename = os.path.expanduser('~/.ssh/id_rsa')
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if os.access(filename, os.R_OK):
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return filename
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filename = os.path.expanduser('~/.ssh/id_dsa')
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if os.access(filename, os.R_OK):
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return filename
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return ''
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def verbose(s):
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if VERBOSE:
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print s
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#####
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parser = OptionParser(usage='usage: %prog [options] <remote-addr>:<remote-port>',
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version='%prog 1.0')
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parser.add_option('-q', '--quiet', action='store_false', dest='verbose', default=VERBOSE,
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help='squelch all informational output')
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parser.add_option('-l', '--local-port', action='store', type='int', dest='port',
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default=DEFAULT_PORT,
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help='local port to forward (default: %d)' % DEFAULT_PORT)
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parser.add_option('-r', '--host', action='store', type='string', dest='ssh_host',
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help='SSH host to tunnel through (required)')
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parser.add_option('-p', '--port', action='store', type='int', dest='ssh_port', default=SSH_PORT,
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help='SSH port to tunnel through (default: %d)' % SSH_PORT)
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parser.add_option('-u', '--user', action='store', type='string', dest='user',
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default=getpass.getuser(),
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help='username for SSH authentication (default: %s)' % getpass.getuser())
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parser.add_option('-K', '--key', action='store', type='string', dest='keyfile',
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default=find_default_key_file(),
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help='private key file to use for SSH authentication')
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parser.add_option('', '--no-key', action='store_false', dest='use_key', default=True,
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help='don\'t look for or use a private key file')
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parser.add_option('-P', '--password', action='store_true', dest='readpass', default=READPASS,
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help='read password (for key or password auth) from stdin')
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options, args = parser.parse_args()
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VERBOSE = options.verbose
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READPASS = options.readpass
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if len(args) != 1:
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parser.error('Incorrect number of arguments.')
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remote_host = args[0]
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if ':' not in remote_host:
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parser.error('Remote port missing.')
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remote_host, remote_port = remote_host.split(':', 1)
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try:
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remote_port = int(remote_port)
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except:
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parser.error('Remote port must be a number.')
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if not options.ssh_host:
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parser.error('SSH host is required.')
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if ':' in options.ssh_host:
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options.ssh_host, options.ssh_port = options.ssh_host.split(':', 1)
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try:
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options.ssh_port = int(options.ssh_port)
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except:
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parser.error('SSH port must be a number.')
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host_keys = load_host_keys()
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if not host_keys.has_key(options.ssh_host):
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print '*** Warning: no host key for %s' % options.ssh_host
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expected_host_key_type = None
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expected_host_key = None
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else:
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expected_host_key_type = host_keys[options.ssh_host].keys()[0]
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expected_host_key = host_keys[options.ssh_host][expected_host_key_type]
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key = None
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password = None
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if options.use_key:
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try:
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key = paramiko.RSAKey.from_private_key_file(options.keyfile)
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except paramiko.PasswordRequiredException:
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if not READPASS:
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print '*** Password needed for keyfile (use -P): %s' % options.keyfile
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sys.exit(1)
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key_password = raw_input()
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try:
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key = paramiko.RSAKey.from_private_key_file(options.keyfile, key_password)
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except:
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print '*** Unable to read keyfile: %s' % options.keyfile
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sys.exit(1)
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except:
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pass
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if key is None:
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# try reading a password then
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if not READPASS:
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print '*** Either a valid private key or password is required (use -K or -P).'
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sys.exit(1)
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password = raw_input()
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verbose('Connecting to ssh host %s:%d ...' % (options.ssh_host, options.ssh_port))
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transport = paramiko.Transport((options.ssh_host, options.ssh_port))
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transport.connect(hostkeytype=expected_host_key_type,
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hostkey=expected_host_key,
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username=options.user,
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password=password,
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pkey=key)
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verbose('Now forwarding port %d to %s:%d ...' % (options.port, remote_host, remote_port))
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try:
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forward_tunnel(options.port, remote_host, remote_port, transport)
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except KeyboardInterrupt:
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print 'Port forwarding stopped.'
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sys.exit(0)
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