1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
#!/usr/bin/env python
# Copyright (C) 2008 Robey Pointer <robeypointer@gmail.com>
#
# This file is part of paramiko.
#
# Paramiko is free software; you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option)
# any later version.
#
# Paramiko 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
"""
Sample script showing how to do remote port forwarding over paramiko.
This script connects to the requested SSH server and sets up remote port
forwarding (the openssh -R option) from a remote port through a tunneled
connection to a destination reachable from the local machine.
"""
import getpass
import os
import socket
import select
import sys
import threading
from optparse import OptionParser
import paramiko
SSH_PORT = 22
DEFAULT_PORT = 4000
g_verbose = True
def handler(chan, host, port):
sock = socket.socket()
try:
sock.connect((host, port))
except Exception as e:
verbose("Forwarding request to %s:%d failed: %r" % (host, port, e))
return
verbose(
"Connected! Tunnel open %r -> %r -> %r"
% (chan.origin_addr, chan.getpeername(), (host, port))
)
while True:
r, w, x = select.select([sock, chan], [], [])
if sock in r:
data = sock.recv(1024)
if len(data) == 0:
break
chan.send(data)
if chan in r:
data = chan.recv(1024)
if len(data) == 0:
break
sock.send(data)
chan.close()
sock.close()
verbose("Tunnel closed from %r" % (chan.origin_addr,))
def reverse_forward_tunnel(server_port, remote_host, remote_port, transport):
transport.request_port_forward("", server_port)
while True:
chan = transport.accept(1000)
if chan is None:
continue
thr = threading.Thread(target=handler, args=(chan, remote_host, remote_port))
thr.setDaemon(True)
thr.start()
def verbose(s):
if g_verbose:
print(s)
HELP = """\
Set up a reverse forwarding tunnel across an SSH server, using paramiko. A
port on the SSH server (given with -p) is forwarded across an SSH session
back to the local machine, and out to a remote site reachable from this
network. This is similar to the openssh -R option.
"""
def get_host_port(spec, default_port):
"parse 'hostname:22' into a host and port, with the port optional"
args = (spec.split(":", 1) + [default_port])[:2]
args[1] = int(args[1])
return args[0], args[1]
def parse_options():
global g_verbose
parser = OptionParser(
usage="usage: %prog [options] <ssh-server>[:<server-port>]",
version="%prog 1.0",
description=HELP,
)
parser.add_option(
"-q",
"--quiet",
action="store_false",
dest="verbose",
default=True,
help="squelch all informational output",
)
parser.add_option(
"-p",
"--remote-port",
action="store",
type="int",
dest="port",
default=DEFAULT_PORT,
help="port on server to forward (default: %d)" % DEFAULT_PORT,
)
parser.add_option(
"-u",
"--user",
action="store",
type="string",
dest="user",
default=getpass.getuser(),
help="username for SSH authentication (default: %s)" % getpass.getuser(),
)
parser.add_option(
"-K",
"--key",
action="store",
type="string",
dest="keyfile",
default=None,
help="private key file to use for SSH authentication",
)
parser.add_option(
"",
"--no-key",
action="store_false",
dest="look_for_keys",
default=True,
help="don't look for or use a private key file",
)
parser.add_option(
"-P",
"--password",
action="store_true",
dest="readpass",
default=False,
help="read password (for key or password auth) from stdin",
)
parser.add_option(
"-r",
"--remote",
action="store",
type="string",
dest="remote",
default=None,
metavar="host:port",
help="remote host and port to forward to",
)
options, args = parser.parse_args()
if len(args) != 1:
parser.error("Incorrect number of arguments.")
if options.remote is None:
parser.error("Remote address required (-r).")
g_verbose = options.verbose
server_host, server_port = get_host_port(args[0], SSH_PORT)
remote_host, remote_port = get_host_port(options.remote, SSH_PORT)
return options, (server_host, server_port), (remote_host, remote_port)
def main():
options, server, remote = parse_options()
password = None
if options.readpass:
password = getpass.getpass("Enter SSH password: ")
client = paramiko.SSHClient()
client.load_system_host_keys()
client.set_missing_host_key_policy(paramiko.WarningPolicy())
verbose("Connecting to ssh host %s:%d ..." % (server[0], server[1]))
try:
client.connect(
server[0],
server[1],
username=options.user,
key_filename=options.keyfile,
look_for_keys=options.look_for_keys,
password=password,
)
except Exception as e:
print("*** Failed to connect to %s:%d: %r" % (server[0], server[1], e))
sys.exit(1)
verbose(
"Now forwarding remote port %d to %s:%d ..."
% (options.port, remote[0], remote[1])
)
try:
reverse_forward_tunnel(
options.port, remote[0], remote[1], client.get_transport()
)
except KeyboardInterrupt:
print("C-c: Port forwarding stopped.")
sys.exit(0)
if __name__ == "__main__":
main()
|
