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sshuttle
Commit ac723694 authored by Brian May's avatar Brian May
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Restructure code 

Pull out firewall methods code into seperate files.

Fix problems starting with method=='auto'; we were making decisions
based on the method, before the method had been finalized by the
firewall.

Only very basic testing so far. What could go wrong?
parent bcd3205d
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Showing with 1138 additions and 972 deletions
sshuttle/__main__.py
View file @ ac723694
......@@ -149,13 +149,10 @@ helpers.verbose = opt.verbose
try:
if opt.firewall:
if len(extra) != 6:
o.fatal('exactly six arguments expected')
port, dnsport = int(extra[0]), int(extra[1])
nslist = [family_ip_tuple(ns) for ns in parse_list(opt.ns_hosts)]
sys.exit(firewall.main(int(extra[0]), int(extra[1]),
int(extra[2]), int(extra[3]), nslist,
extra[4], int(extra[5]), opt.syslog))
if len(extra) != 0:
o.fatal('exactly zero arguments expected')
result = firewall.main(opt.method, opt.syslog)
sys.exit(result)
elif opt.hostwatch:
sys.exit(hostwatch.hw_main(extra))
else:
......@@ -183,23 +180,20 @@ try:
if opt.subnets:
includes = parse_subnet_file(opt.subnets)
if not opt.method:
method = "auto"
method_name = "auto"
elif opt.method in ["auto", "nat", "tproxy", "ipfw", "pf"]:
method = opt.method
method_name = opt.method
else:
o.fatal("method %s not supported" % opt.method)
o.fatal("method_name %s not supported" % opt.method)
if not opt.listen:
if opt.method == "tproxy":
ipport_v6 = parse_ipport6('[::1]:0')
else:
ipport_v6 = None
ipport_v4 = parse_ipport4('127.0.0.1:0')
ipport_v6 = "auto" # parse_ipport6('[::1]:0')
ipport_v4 = "auto" # parse_ipport4('127.0.0.1:0')
else:
ipport_v6 = None
ipport_v4 = None
list = opt.listen.split(",")
for ip in list:
if '[' in ip and ']' in ip and opt.method == "tproxy":
if '[' in ip and ']' in ip:
ipport_v6 = parse_ipport6(ip)
else:
ipport_v4 = parse_ipport4(ip)
......@@ -210,7 +204,7 @@ try:
opt.latency_control,
opt.dns,
nslist,
method,
method_name,
sh,
opt.auto_nets,
parse_subnets(includes),
......
sshuttle/client.py
View file @ ac723694
import struct
import socket
import errno
import re
import signal
......@@ -13,23 +13,7 @@ import sys
from sshuttle.ssnet import SockWrapper, Handler, Proxy, Mux, MuxWrapper
from sshuttle.helpers import log, debug1, debug2, debug3, Fatal, islocal, \
resolvconf_nameservers
recvmsg = None
try:
# try getting recvmsg from python
import socket as pythonsocket
getattr(pythonsocket.socket, "recvmsg")
socket = pythonsocket
recvmsg = "python"
except AttributeError:
# try getting recvmsg from socket_ext library
try:
import socket_ext
getattr(socket_ext.socket, "recvmsg")
socket = socket_ext
recvmsg = "socket_ext"
except ImportError:
import socket
from sshuttle.methods import get_method
_extra_fd = os.open('/dev/null', os.O_RDONLY)
......@@ -40,83 +24,6 @@ def got_signal(signum, frame):
_pidname = None
IP_TRANSPARENT = 19
IP_ORIGDSTADDR = 20
IP_RECVORIGDSTADDR = IP_ORIGDSTADDR
SOL_IPV6 = 41
IPV6_ORIGDSTADDR = 74
IPV6_RECVORIGDSTADDR = IPV6_ORIGDSTADDR
if recvmsg == "python":
def recv_udp(listener, bufsize):
debug3('Accept UDP python using recvmsg.\n')
data, ancdata, msg_flags, srcip = listener.recvmsg(
4096, socket.CMSG_SPACE(24))
dstip = None
family = None
for cmsg_level, cmsg_type, cmsg_data in ancdata:
if cmsg_level == socket.SOL_IP and cmsg_type == IP_ORIGDSTADDR:
family, port = struct.unpack('=HH', cmsg_data[0:4])
port = socket.htons(port)
if family == socket.AF_INET:
start = 4
length = 4
else:
raise Fatal("Unsupported socket type '%s'" % family)
ip = socket.inet_ntop(family, cmsg_data[start:start + length])
dstip = (ip, port)
break
elif cmsg_level == SOL_IPV6 and cmsg_type == IPV6_ORIGDSTADDR:
family, port = struct.unpack('=HH', cmsg_data[0:4])
port = socket.htons(port)
if family == socket.AF_INET6:
start = 8
length = 16
else:
raise Fatal("Unsupported socket type '%s'" % family)
ip = socket.inet_ntop(family, cmsg_data[start:start + length])
dstip = (ip, port)
break
return (srcip, dstip, data)
elif recvmsg == "socket_ext":
def recv_udp(listener, bufsize):
debug3('Accept UDP using socket_ext recvmsg.\n')
srcip, data, adata, flags = listener.recvmsg(
(bufsize,), socket.CMSG_SPACE(24))
dstip = None
family = None
for a in adata:
if a.cmsg_level == socket.SOL_IP and a.cmsg_type == IP_ORIGDSTADDR:
family, port = struct.unpack('=HH', a.cmsg_data[0:4])
port = socket.htons(port)
if family == socket.AF_INET:
start = 4
length = 4
else:
raise Fatal("Unsupported socket type '%s'" % family)
ip = socket.inet_ntop(
family, a.cmsg_data[start:start + length])
dstip = (ip, port)
break
elif a.cmsg_level == SOL_IPV6 and a.cmsg_type == IPV6_ORIGDSTADDR:
family, port = struct.unpack('=HH', a.cmsg_data[0:4])
port = socket.htons(port)
if family == socket.AF_INET6:
start = 8
length = 16
else:
raise Fatal("Unsupported socket type '%s'" % family)
ip = socket.inet_ntop(
family, a.cmsg_data[start:start + length])
dstip = (ip, port)
break
return (srcip, dstip, data[0])
else:
def recv_udp(listener, bufsize):
debug3('Accept UDP using recvfrom.\n')
data, srcip = listener.recvfrom(bufsize)
return (srcip, None, data)
def check_daemon(pidfile):
......@@ -185,40 +92,7 @@ def daemon_cleanup():
else:
raise
pf_command_file = None
def pf_dst(sock):
peer = sock.getpeername()
proxy = sock.getsockname()
argv = (sock.family, socket.IPPROTO_TCP,
peer[0], peer[1], proxy[0], proxy[1])
pf_command_file.write("QUERY_PF_NAT %r,%r,%s,%r,%s,%r\n" % argv)
pf_command_file.flush()
line = pf_command_file.readline()
debug2("QUERY_PF_NAT %r,%r,%s,%r,%s,%r" % argv + ' > ' + line)
if line.startswith('QUERY_PF_NAT_SUCCESS '):
(ip, port) = line[21:].split(',')
return (ip, int(port))
return sock.getsockname()
def original_dst(sock):
try:
SO_ORIGINAL_DST = 80
SOCKADDR_MIN = 16
sockaddr_in = sock.getsockopt(socket.SOL_IP,
SO_ORIGINAL_DST, SOCKADDR_MIN)
(proto, port, a, b, c, d) = struct.unpack('!HHBBBB', sockaddr_in[:8])
assert(socket.htons(proto) == socket.AF_INET)
ip = '%d.%d.%d.%d' % (a, b, c, d)
return (ip, port)
except socket.error as e:
if e.args[0] == errno.ENOPROTOOPT:
return sock.getsockname()
raise
firewall = None
class MultiListener:
......@@ -280,24 +154,18 @@ class MultiListener:
class FirewallClient:
def __init__(self, port_v6, port_v4, subnets_include, subnets_exclude,
dnsport_v6, dnsport_v4, nslist, method, udp):
def __init__(self, method_name):
self.auto_nets = []
self.subnets_include = subnets_include
self.subnets_exclude = subnets_exclude
python_path = os.path.dirname(os.path.dirname(__file__))
argvbase = (["PYTHONPATH=%s" % python_path] +
[sys.executable, sys.argv[0]] +
argvbase = ([sys.executable, sys.argv[0]] +
['-v'] * (helpers.verbose or 0) +
['--firewall', str(port_v6), str(port_v4),
str(dnsport_v6), str(dnsport_v4),
method, str(int(udp))])
if dnsport_v4 or dnsport_v6:
argvbase += ['--ns-hosts', ' '.join([ip for _, ip in nslist])]
['--method', method_name] +
['--firewall'])
if ssyslog._p:
argvbase += ['--syslog']
argv_tries = [
['sudo', '-p', '[local sudo] Password: '] + argvbase,
['sudo', '-p', '[local sudo] Password: ',
('PYTHONPATH=%s' % python_path), '--'] + argvbase,
argvbase
]
......@@ -337,7 +205,19 @@ class FirewallClient:
self.check()
if line[0:5] != b'READY':
raise Fatal('%r expected READY, got %r' % (self.argv, line))
self.method = line[6:-1]
method_name = line[6:-1]
self.method = get_method(method_name.decode("ASCII"))
def setup(self, subnets_include, subnets_exclude, nslist,
redirectport_v6, redirectport_v4, dnsport_v6, dnsport_v4, udp):
self.subnets_include = subnets_include
self.subnets_exclude = subnets_exclude
self.nslist = nslist
self.redirectport_v6 = redirectport_v6
self.redirectport_v4 = redirectport_v4
self.dnsport_v6 = dnsport_v6
self.dnsport_v4 = dnsport_v4
self.udp = udp
def check(self):
rv = self.p.poll()
......@@ -346,18 +226,30 @@ class FirewallClient:
def start(self):
self.pfile.write(b'ROUTES\n')
try:
for (family, ip, width) in self.subnets_include + self.auto_nets:
self.pfile.write(b'%d,%d,0,%s\n'
% (family, width, ip.encode("ASCII")))
for (family, ip, width) in self.subnets_exclude:
self.pfile.write(b'%d,%d,1,%s\n'
% (family, width, ip.encode("ASCII")))
except Exception as e:
debug1("exception occured %r" % e)
raise
self.pfile.write(b'GO\n')
self.pfile.write(b'NSLIST\n')
for (family, ip) in self.nslist:
self.pfile.write(b'%d,%s\n'
% (family, ip.encode("ASCII")))
self.pfile.write(
b'PORTS %d,%d,%d,%d\n'
% (self.redirectport_v6, self.redirectport_v4,
self.dnsport_v6, self.dnsport_v4))
udp = 0
if self.udp:
udp = 1
self.pfile.write(b'GO %d\n' % udp)
self.pfile.flush()
line = self.pfile.readline()
self.check()
if line != b'STARTED\n':
......@@ -413,12 +305,8 @@ def onaccept_tcp(listener, method, mux, handlers):
return
else:
raise
if method == b"tproxy":
dstip = sock.getsockname()
elif method == b"pf":
dstip = pf_dst(sock)
else:
dstip = original_dst(sock)
dstip = method.get_tcp_dstip(sock)
debug1('Accept TCP: %s:%r -> %s:%r.\n' % (srcip[0], srcip[1],
dstip[0], dstip[1]))
if dstip[1] == sock.getsockname()[1] and islocal(dstip[0], sock.family):
......@@ -437,37 +325,26 @@ def onaccept_tcp(listener, method, mux, handlers):
expire_connections(time.time(), mux)
def udp_done(chan, data, method, family, dstip):
def udp_done(chan, data, method, sock, dstip):
(src, srcport, data) = data.split(",", 2)
srcip = (src, int(srcport))
debug3('doing send from %r to %r\n' % (srcip, dstip,))
try:
sender = socket.socket(family, socket.SOCK_DGRAM)
sender.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sender.setsockopt(socket.SOL_IP, IP_TRANSPARENT, 1)
sender.bind(srcip)
sender.sendto(data, dstip)
sender.close()
except socket.error as e:
debug1('-- ignored socket error sending UDP data: %r\n' % e)
method.send_udp(sock, srcip, dstip, data)
def onaccept_udp(listener, method, mux, handlers):
now = time.time()
srcip, dstip, data = recv_udp(listener, 4096)
if not dstip:
debug1(
"-- ignored UDP from %r: "
"couldn't determine destination IP address\n" % (srcip,))
t = method.recv_udp(listener, 4096)
if t is None:
return
srcip, dstip, data = t
debug1('Accept UDP: %r -> %r.\n' % (srcip, dstip,))
if srcip in udp_by_src:
chan, timeout = udp_by_src[srcip]
else:
chan = mux.next_channel()
mux.channels[chan] = lambda cmd, data: udp_done(
chan, data, method, listener.family, dstip=srcip)
chan, data, method, listener, dstip=srcip)
mux.send(chan, ssnet.CMD_UDP_OPEN, listener.family)
udp_by_src[srcip] = chan, now + 30
......@@ -481,27 +358,15 @@ def dns_done(chan, data, method, sock, srcip, dstip, mux):
debug3('dns_done: channel=%d src=%r dst=%r\n' % (chan, srcip, dstip))
del mux.channels[chan]
del dnsreqs[chan]
if method == b"tproxy":
debug3('doing send from %r to %r\n' % (srcip, dstip,))
sender = socket.socket(sock.family, socket.SOCK_DGRAM)
sender.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sender.setsockopt(socket.SOL_IP, IP_TRANSPARENT, 1)
sender.bind(srcip)
sender.sendto(data, dstip)
sender.close()
else:
debug3('doing sendto %r\n' % (dstip,))
sock.sendto(data, dstip)
method.send_udp(sock, srcip, dstip, data)
def ondns(listener, method, mux, handlers):
now = time.time()
srcip, dstip, data = recv_udp(listener, 4096)
if method == b"tproxy" and not dstip:
debug1(
"-- ignored UDP from %r: "
"couldn't determine destination IP address\n" % (srcip,))
t = method.recv_udp(listener, 4096)
if t is None:
return
srcip, dstip, data = t
debug1('DNS request from %r to %r: %d bytes\n' % (srcip, dstip, len(data)))
chan = mux.next_channel()
dnsreqs[chan] = now + 30
......@@ -513,8 +378,11 @@ def ondns(listener, method, mux, handlers):
def _main(tcp_listener, udp_listener, fw, ssh_cmd, remotename,
python, latency_control,
dns_listener, method, seed_hosts, auto_nets,
dns_listener, seed_hosts, auto_nets,
syslog, daemon):
method = fw.method
handlers = []
if helpers.verbose >= 1:
helpers.logprefix = 'c : '
......@@ -526,7 +394,7 @@ def _main(tcp_listener, udp_listener, fw, ssh_cmd, remotename,
(serverproc, serversock) = ssh.connect(
ssh_cmd, remotename, python,
stderr=ssyslog._p and ssyslog._p.stdin,
options=dict(latency_control=latency_control, method=method))
options=dict(latency_control=latency_control))
except socket.error as e:
if e.args[0] == errno.EPIPE:
raise Fatal("failed to establish ssh session (1)")
......@@ -618,7 +486,7 @@ def _main(tcp_listener, udp_listener, fw, ssh_cmd, remotename,
def main(listenip_v6, listenip_v4,
ssh_cmd, remotename, python, latency_control, dns, nslist,
method, seed_hosts, auto_nets,
method_name, seed_hosts, auto_nets,
subnets_include, subnets_exclude, syslog, daemon, pidfile):
if syslog:
......@@ -631,22 +499,20 @@ def main(listenip_v6, listenip_v4,
return 5
debug1('Starting sshuttle proxy.\n')
if recvmsg is not None:
debug1("recvmsg %s support enabled.\n" % recvmsg)
fw = FirewallClient(method_name)
if method == b"tproxy":
if recvmsg is not None:
debug1("tproxy UDP support enabled.\n")
udp = True
else:
debug1("tproxy UDP support requires recvmsg function.\n")
udp = False
if dns and recvmsg is None:
debug1("tproxy DNS support requires recvmsg function.\n")
dns = False
features = fw.method.get_supported_features()
if listenip_v6 == "auto":
if features.ipv6:
listenip_v6 = ('::1', 0)
else:
debug1("UDP support requires tproxy; disabling UDP.\n")
udp = False
listenip_v6 = None
if listenip_v4 == "auto":
listenip_v4 = ('127.0.0.1', 0)
udp = features.udp
debug1("UDP enabled: %r\n" % udp)
if listenip_v6 and listenip_v6[1] and listenip_v4 and listenip_v4[1]:
# if both ports given, no need to search for a spare port
......@@ -703,6 +569,7 @@ def main(listenip_v6, listenip_v4,
last_e = e
else:
raise e
debug2('\n')
if not bound:
assert(last_e)
......@@ -716,6 +583,7 @@ def main(listenip_v6, listenip_v4,
if dns or nslist:
if dns:
nslist += resolvconf_nameservers()
dns = True
# search for spare port for DNS
debug2('Binding DNS:')
ports = range(12300, 9000, -1)
......@@ -756,35 +624,25 @@ def main(listenip_v6, listenip_v4,
dnsport_v4 = 0
dns_listener = None
fw = FirewallClient(redirectport_v6, redirectport_v4, subnets_include,
subnets_exclude, dnsport_v6, dnsport_v4, nslist,
method, udp)
if fw.method == b"tproxy":
tcp_listener.setsockopt(socket.SOL_IP, IP_TRANSPARENT, 1)
fw.method.check_settings(udp, dns)
fw.method.setup_tcp_listener(tcp_listener)
if udp_listener:
udp_listener.setsockopt(socket.SOL_IP, IP_TRANSPARENT, 1)
if udp_listener.v4 is not None:
udp_listener.v4.setsockopt(
socket.SOL_IP, IP_RECVORIGDSTADDR, 1)
if udp_listener.v6 is not None:
udp_listener.v6.setsockopt(SOL_IPV6, IPV6_RECVORIGDSTADDR, 1)
fw.method.setup_udp_listener(tcp_listener)
if dns_listener:
dns_listener.setsockopt(socket.SOL_IP, IP_TRANSPARENT, 1)
if dns_listener.v4 is not None:
dns_listener.v4.setsockopt(
socket.SOL_IP, IP_RECVORIGDSTADDR, 1)
if dns_listener.v6 is not None:
dns_listener.v6.setsockopt(SOL_IPV6, IPV6_RECVORIGDSTADDR, 1)
fw.method.setup_udp_listener(dns_listener)
fw.setup(subnets_include, subnets_exclude, nslist,
redirectport_v6, redirectport_v4, dnsport_v6, dnsport_v4,
udp)
if fw.method == b"pf":
global pf_command_file
pf_command_file = fw.pfile
# kludge for PF method.
global firewall
firewall = fw
try:
return _main(tcp_listener, udp_listener, fw, ssh_cmd, remotename,
python, latency_control, dns_listener,
fw.method, seed_hosts, auto_nets, syslog,
seed_hosts, auto_nets, syslog,
daemon)
finally:
try:
......
sshuttle/firewall.py
View file @ ac723694
import errno
import socket
import select
import signal
import struct
import subprocess as ssubprocess
import sshuttle.ssyslog as ssyslog
import sys
import os
import re
from sshuttle.helpers import log, debug1, debug3, islocal, \
Fatal, family_to_string
from fcntl import ioctl
from ctypes import c_char, c_uint8, c_uint16, c_uint32, Union, Structure, \
sizeof, addressof, memmove
# python doesn't have a definition for this
IPPROTO_DIVERT = 254
def nonfatal(func, *args):
try:
func(*args)
except Fatal as e:
log('error: %s\n' % e)
def ipt_chain_exists(family, table, name):
if family == socket.AF_INET6:
cmd = 'ip6tables'
elif family == socket.AF_INET:
cmd = 'iptables'
else:
raise Exception('Unsupported family "%s"' % family_to_string(family))
argv = [cmd, '-t', table, '-nL']
p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE)
for line in p.stdout:
if line.startswith(b'Chain %s ' % name.encode("ASCII")):
return True
rv = p.wait()
if rv:
raise Fatal('%r returned %d' % (argv, rv))
def _ipt(family, table, *args):
if family == socket.AF_INET6:
argv = ['ip6tables', '-t', table] + list(args)
elif family == socket.AF_INET:
argv = ['iptables', '-t', table] + list(args)
else:
raise Exception('Unsupported family "%s"' % family_to_string(family))
debug1('>> %s\n' % ' '.join(argv))
rv = ssubprocess.call(argv)
if rv:
raise Fatal('%r returned %d' % (argv, rv))
_no_ttl_module = False
def _ipt_ttl(family, *args):
global _no_ttl_module
if not _no_ttl_module:
# we avoid infinite loops by generating server-side connections
# with ttl 42. This makes the client side not recapture those
# connections, in case client == server.
try:
argsplus = list(args) + ['-m', 'ttl', '!', '--ttl', '42']
_ipt(family, *argsplus)
except Fatal:
_ipt(family, *args)
# we only get here if the non-ttl attempt succeeds
log('sshuttle: warning: your iptables is missing '
'the ttl module.\n')
_no_ttl_module = True
else:
_ipt(family, *args)
# We name the chain based on the transproxy port number so that it's possible
# to run multiple copies of sshuttle at the same time. Of course, the
# multiple copies shouldn't have overlapping subnets, or only the most-
# recently-started one will win (because we use "-I OUTPUT 1" instead of
# "-A OUTPUT").
def do_iptables_nat(port, dnsport, nslist, family, subnets, udp):
# only ipv4 supported with NAT
if family != socket.AF_INET:
raise Exception(
'Address family "%s" unsupported by nat method'
% family_to_string(family))
if udp:
raise Exception("UDP not supported by nat method")
table = "nat"
def ipt(*args):
return _ipt(family, table, *args)
def ipt_ttl(*args):
return _ipt_ttl(family, table, *args)
chain = 'sshuttle-%s' % port
# basic cleanup/setup of chains
if ipt_chain_exists(family, table, chain):
nonfatal(ipt, '-D', 'OUTPUT', '-j', chain)
nonfatal(ipt, '-D', 'PREROUTING', '-j', chain)
nonfatal(ipt, '-F', chain)
ipt('-X', chain)
if subnets or dnsport:
ipt('-N', chain)
ipt('-F', chain)
ipt('-I', 'OUTPUT', '1', '-j', chain)
ipt('-I', 'PREROUTING', '1', '-j', chain)
if subnets:
# create new subnet entries. Note that we're sorting in a very
# particular order: we need to go from most-specific (largest swidth)
# to least-specific, and at any given level of specificity, we want
# excludes to come first. That's why the columns are in such a non-
# intuitive order.
for f, swidth, sexclude, snet \
in sorted(subnets, key=lambda s: s[1], reverse=True):
if sexclude:
ipt('-A', chain, '-j', 'RETURN',
'--dest', '%s/%s' % (snet, swidth),
'-p', 'tcp')
else:
ipt_ttl('-A', chain, '-j', 'REDIRECT',
'--dest', '%s/%s' % (snet, swidth),
'-p', 'tcp',
'--to-ports', str(port))
if dnsport:
for f, ip in [i for i in nslist if i[0] == family]:
ipt_ttl('-A', chain, '-j', 'REDIRECT',
'--dest', '%s/32' % ip,
'-p', 'udp',
'--dport', '53',
'--to-ports', str(dnsport))
def do_iptables_tproxy(port, dnsport, nslist, family, subnets, udp):
if family not in [socket.AF_INET, socket.AF_INET6]:
raise Exception(
'Address family "%s" unsupported by tproxy method'
% family_to_string(family))
table = "mangle"
def ipt(*args):
return _ipt(family, table, *args)
def ipt_ttl(*args):
return _ipt_ttl(family, table, *args)
mark_chain = 'sshuttle-m-%s' % port
tproxy_chain = 'sshuttle-t-%s' % port
divert_chain = 'sshuttle-d-%s' % port
# basic cleanup/setup of chains
if ipt_chain_exists(family, table, mark_chain):
ipt('-D', 'OUTPUT', '-j', mark_chain)
ipt('-F', mark_chain)
ipt('-X', mark_chain)
if ipt_chain_exists(family, table, tproxy_chain):
ipt('-D', 'PREROUTING', '-j', tproxy_chain)
ipt('-F', tproxy_chain)
ipt('-X', tproxy_chain)
if ipt_chain_exists(family, table, divert_chain):
ipt('-F', divert_chain)
ipt('-X', divert_chain)
if subnets or dnsport:
ipt('-N', mark_chain)
ipt('-F', mark_chain)
ipt('-N', divert_chain)
ipt('-F', divert_chain)
ipt('-N', tproxy_chain)
ipt('-F', tproxy_chain)
ipt('-I', 'OUTPUT', '1', '-j', mark_chain)
ipt('-I', 'PREROUTING', '1', '-j', tproxy_chain)
ipt('-A', divert_chain, '-j', 'MARK', '--set-mark', '1')
ipt('-A', divert_chain, '-j', 'ACCEPT')
ipt('-A', tproxy_chain, '-m', 'socket', '-j', divert_chain,
'-m', 'tcp', '-p', 'tcp')
if subnets and udp:
ipt('-A', tproxy_chain, '-m', 'socket', '-j', divert_chain,
'-m', 'udp', '-p', 'udp')
if dnsport:
for f, ip in [i for i in nslist if i[0] == family]:
ipt('-A', mark_chain, '-j', 'MARK', '--set-mark', '1',
'--dest', '%s/32' % ip,
'-m', 'udp', '-p', 'udp', '--dport', '53')
ipt('-A', tproxy_chain, '-j', 'TPROXY', '--tproxy-mark', '0x1/0x1',
'--dest', '%s/32' % ip,
'-m', 'udp', '-p', 'udp', '--dport', '53',
'--on-port', str(dnsport))
if subnets:
for f, swidth, sexclude, snet \
in sorted(subnets, key=lambda s: s[1], reverse=True):
if sexclude:
ipt('-A', mark_chain, '-j', 'RETURN',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'tcp', '-p', 'tcp')
ipt('-A', tproxy_chain, '-j', 'RETURN',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'tcp', '-p', 'tcp')
else:
ipt('-A', mark_chain, '-j', 'MARK',
'--set-mark', '1',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'tcp', '-p', 'tcp')
ipt('-A', tproxy_chain, '-j', 'TPROXY',
'--tproxy-mark', '0x1/0x1',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'tcp', '-p', 'tcp',
'--on-port', str(port))
if sexclude and udp:
ipt('-A', mark_chain, '-j', 'RETURN',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'udp', '-p', 'udp')
ipt('-A', tproxy_chain, '-j', 'RETURN',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'udp', '-p', 'udp')
elif udp:
ipt('-A', mark_chain, '-j', 'MARK',
'--set-mark', '1',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'udp', '-p', 'udp')
ipt('-A', tproxy_chain, '-j', 'TPROXY',
'--tproxy-mark', '0x1/0x1',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'udp', '-p', 'udp',
'--on-port', str(port))
def ipfw_rule_exists(n):
argv = ['ipfw', 'list']
p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE)
found = False
for line in p.stdout:
if line.startswith('%05d ' % n):
if not ('ipttl 42' in line
or ('skipto %d' % (n + 1)) in line
or 'check-state' in line):
log('non-sshuttle ipfw rule: %r\n' % line.strip())
raise Fatal('non-sshuttle ipfw rule #%d already exists!' % n)
found = True
rv = p.wait()
if rv:
raise Fatal('%r returned %d' % (argv, rv))
return found
_oldctls = {}
def _fill_oldctls(prefix):
argv = ['sysctl', prefix]
p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE)
for line in p.stdout:
assert(line[-1] == '\n')
(k, v) = line[:-1].split(': ', 1)
_oldctls[k] = v
rv = p.wait()
if rv:
raise Fatal('%r returned %d' % (argv, rv))
if not line:
raise Fatal('%r returned no data' % (argv,))
def _sysctl_set(name, val):
argv = ['sysctl', '-w', '%s=%s' % (name, val)]
debug1('>> %s\n' % ' '.join(argv))
return ssubprocess.call(argv, stdout=open('/dev/null', 'w'))
_changedctls = []
def sysctl_set(name, val, permanent=False):
PREFIX = 'net.inet.ip'
assert(name.startswith(PREFIX + '.'))
val = str(val)
if not _oldctls:
_fill_oldctls(PREFIX)
if not (name in _oldctls):
debug1('>> No such sysctl: %r\n' % name)
return False
oldval = _oldctls[name]
if val != oldval:
rv = _sysctl_set(name, val)
if rv == 0 and permanent:
debug1('>> ...saving permanently in /etc/sysctl.conf\n')
f = open('/etc/sysctl.conf', 'a')
f.write('\n'
'# Added by sshuttle\n'
'%s=%s\n' % (name, val))
f.close()
else:
_changedctls.append(name)
return True
def _udp_unpack(p):
src = (socket.inet_ntoa(p[12:16]), struct.unpack('!H', p[20:22])[0])
dst = (socket.inet_ntoa(p[16:20]), struct.unpack('!H', p[22:24])[0])
return src, dst
def _udp_repack(p, src, dst):
addrs = socket.inet_aton(src[0]) + socket.inet_aton(dst[0])
ports = struct.pack('!HH', src[1], dst[1])
return p[:12] + addrs + ports + p[24:]
_real_dns_server = [None]
def _handle_diversion(divertsock, dnsport):
p, tag = divertsock.recvfrom(4096)
src, dst = _udp_unpack(p)
debug3('got diverted packet from %r to %r\n' % (src, dst))
if dst[1] == 53:
# outgoing DNS
debug3('...packet is a DNS request.\n')
_real_dns_server[0] = dst
dst = ('127.0.0.1', dnsport)
elif src[1] == dnsport:
if islocal(src[0], divertsock.family):
debug3('...packet is a DNS response.\n')
src = _real_dns_server[0]
else:
log('weird?! unexpected divert from %r to %r\n' % (src, dst))
assert(0)
newp = _udp_repack(p, src, dst)
divertsock.sendto(newp, tag)
def ipfw(*args):
argv = ['ipfw', '-q'] + list(args)
debug1('>> %s\n' % ' '.join(argv))
rv = ssubprocess.call(argv)
if rv:
raise Fatal('%r returned %d' % (argv, rv))
def do_ipfw(port, dnsport, nslist, family, subnets, udp):
# IPv6 not supported
if family not in [socket.AF_INET, ]:
raise Exception(
'Address family "%s" unsupported by ipfw method'
% family_to_string(family))
if udp:
raise Exception("UDP not supported by ipfw method")
sport = str(port)
xsport = str(port + 1)
# cleanup any existing rules
if ipfw_rule_exists(port):
ipfw('delete', sport)
while _changedctls:
name = _changedctls.pop()
oldval = _oldctls[name]
_sysctl_set(name, oldval)
if subnets or dnsport:
sysctl_set('net.inet.ip.fw.enable', 1)
changed = sysctl_set('net.inet.ip.scopedroute', 0, permanent=True)
if changed:
log("\n"
" WARNING: ONE-TIME NETWORK DISRUPTION:\n"
" =====================================\n"
"sshuttle has changed a MacOS kernel setting to work around\n"
"a bug in MacOS 10.6. This will cause your network to drop\n"
"within 5-10 minutes unless you restart your network\n"
"interface (change wireless networks or unplug/plug the\n"
"ethernet port) NOW, then restart sshuttle. The fix is\n"
"permanent; you only have to do this once.\n\n")
sys.exit(1)
ipfw('add', sport, 'check-state', 'ip',
'from', 'any', 'to', 'any')
if subnets:
# create new subnet entries
for f, swidth, sexclude, snet \
in sorted(subnets, key=lambda s: s[1], reverse=True):
if sexclude:
ipfw('add', sport, 'skipto', xsport,
'tcp',
'from', 'any', 'to', '%s/%s' % (snet, swidth))
else:
ipfw('add', sport, 'fwd', '127.0.0.1,%d' % port,
'tcp',
'from', 'any', 'to', '%s/%s' % (snet, swidth),
'not', 'ipttl', '42', 'keep-state', 'setup')
# This part is much crazier than it is on Linux, because MacOS (at least
# 10.6, and probably other versions, and maybe FreeBSD too) doesn't
# correctly fixup the dstip/dstport for UDP packets when it puts them
# through a 'fwd' rule. It also doesn't fixup the srcip/srcport in the
# response packet. In Linux iptables, all that happens magically for us,
# so we just redirect the packets and relax.
#
# On MacOS, we have to fix the ports ourselves. For that, we use a
# 'divert' socket, which receives raw packets and lets us mangle them.
#
# Here's how it works. Let's say the local DNS server is 1.1.1.1:53,
# and the remote DNS server is 2.2.2.2:53, and the local transproxy port
# is 10.0.0.1:12300, and a client machine is making a request from
# 10.0.0.5:9999. We see a packet like this:
# 10.0.0.5:9999 -> 1.1.1.1:53
# Since the destip:port matches one of our local nameservers, it will
# match a 'fwd' rule, thus grabbing it on the local machine. However,
# the local kernel will then see a packet addressed to *:53 and
# not know what to do with it; there's nobody listening on port 53. Thus,
# we divert it, rewriting it into this:
# 10.0.0.5:9999 -> 10.0.0.1:12300
# This gets proxied out to the server, which sends it to 2.2.2.2:53,
# and the answer comes back, and the proxy sends it back out like this:
# 10.0.0.1:12300 -> 10.0.0.5:9999
# But that's wrong! The original machine expected an answer from
# 1.1.1.1:53, so we have to divert the *answer* and rewrite it:
# 1.1.1.1:53 -> 10.0.0.5:9999
#
# See? Easy stuff.
if dnsport:
divertsock = socket.socket(socket.AF_INET, socket.SOCK_RAW,
IPPROTO_DIVERT)
divertsock.bind(('0.0.0.0', port)) # IP field is ignored
for f, ip in [i for i in nslist if i[0] == family]:
# relabel and then catch outgoing DNS requests
ipfw('add', sport, 'divert', sport,
'udp',
'from', 'any', 'to', '%s/32' % ip, '53',
'not', 'ipttl', '42')
# relabel DNS responses
ipfw('add', sport, 'divert', sport,
'udp',
'from', 'any', str(dnsport), 'to', 'any',
'not', 'ipttl', '42')
def do_wait():
while 1:
r, w, x = select.select([sys.stdin, divertsock], [], [])
if divertsock in r:
_handle_diversion(divertsock, dnsport)
if sys.stdin in r:
return
else:
do_wait = None
return do_wait
def pfctl(args, stdin=None):
argv = ['pfctl'] + list(args.split(" "))
debug1('>> %s\n' % ' '.join(argv))
p = ssubprocess.Popen(argv, stdin=ssubprocess.PIPE,
stdout=ssubprocess.PIPE,
stderr=ssubprocess.PIPE)
o = p.communicate(stdin)
if p.returncode:
raise Fatal('%r returned %d' % (argv, p.returncode))
return o
_pf_context = {'started_by_sshuttle': False, 'Xtoken': ''}
def do_pf(port, dnsport, nslist, family, subnets, udp):
global _pf_started_by_sshuttle
tables = []
translating_rules = []
filtering_rules = []
if subnets:
includes = []
# If a given subnet is both included and excluded, list the exclusion
# first; the table will ignore the second, opposite definition
for f, swidth, sexclude, snet \
in sorted(subnets, key=lambda s: (s[1], s[2]), reverse=True):
includes.append("%s%s/%s" %
("!" if sexclude else "", snet, swidth))
tables.append('table <forward_subnets> {%s}' % ','.join(includes))
translating_rules.append(
'rdr pass on lo0 proto tcp '
'to <forward_subnets> -> 127.0.0.1 port %r' % port)
filtering_rules.append(
'pass out route-to lo0 inet proto tcp '
'to <forward_subnets> keep state')
if dnsport:
tables.append('table <dns_servers> {%s}' % ','.join(
[ns[1] for ns in nslist]))
translating_rules.append(
'rdr pass on lo0 proto udp to '
'<dns_servers> port 53 -> 127.0.0.1 port %r' % dnsport)
filtering_rules.append(
'pass out route-to lo0 inet proto udp to '
'<dns_servers> port 53 keep state')
rules = '\n'.join(tables + translating_rules + filtering_rules) + '\n'
pf_status = pfctl('-s all')[0]
if '\nrdr-anchor "sshuttle" all\n' not in pf_status:
pf_add_anchor_rule(PF_RDR, "sshuttle")
if '\nanchor "sshuttle" all\n' not in pf_status:
pf_add_anchor_rule(PF_PASS, "sshuttle")
pfctl('-a sshuttle -f /dev/stdin', rules)
if sys.platform == "darwin":
o = pfctl('-E')
_pf_context['Xtoken'] = re.search(r'Token : (.+)', o[1]).group(1)
elif 'INFO:\nStatus: Disabled' in pf_status:
pfctl('-e')
_pf_context['started_by_sshuttle'] = True
else:
pfctl('-a sshuttle -F all')
if sys.platform == "darwin":
pfctl('-X %s' % _pf_context['Xtoken'])
elif _pf_context['started_by_sshuttle']:
pfctl('-d')
def program_exists(name):
paths = (os.getenv('PATH') or os.defpath).split(os.pathsep)
for p in paths:
fn = '%s/%s' % (p, name)
if os.path.exists(fn):
return not os.path.isdir(fn) and os.access(fn, os.X_OK)
from sshuttle.helpers import debug1, debug2, Fatal
from sshuttle.methods import get_auto_method, get_method
hostmap = {}
......@@ -589,122 +51,6 @@ def restore_etc_hosts(port):
rewrite_etc_hosts(port)
# This are some classes and functions used to support pf in yosemite.
class pf_state_xport(Union):
_fields_ = [("port", c_uint16),
("call_id", c_uint16),
("spi", c_uint32)]
class pf_addr(Structure):
class _pfa(Union):
_fields_ = [("v4", c_uint32), # struct in_addr
("v6", c_uint32 * 4), # struct in6_addr
("addr8", c_uint8 * 16),
("addr16", c_uint16 * 8),
("addr32", c_uint32 * 4)]
_fields_ = [("pfa", _pfa)]
_anonymous_ = ("pfa",)
class pfioc_natlook(Structure):
_fields_ = [("saddr", pf_addr),
("daddr", pf_addr),
("rsaddr", pf_addr),
("rdaddr", pf_addr),
("sxport", pf_state_xport),
("dxport", pf_state_xport),
("rsxport", pf_state_xport),
("rdxport", pf_state_xport),
("af", c_uint8), # sa_family_t
("proto", c_uint8),
("proto_variant", c_uint8),
("direction", c_uint8)]
pfioc_rule = c_char * 3104 # sizeof(struct pfioc_rule)
pfioc_pooladdr = c_char * 1136 # sizeof(struct pfioc_pooladdr)
MAXPATHLEN = 1024
DIOCNATLOOK = ((0x40000000 | 0x80000000) | (
(sizeof(pfioc_natlook) & 0x1fff) << 16) | ((ord('D')) << 8) | (23))
DIOCCHANGERULE = ((0x40000000 | 0x80000000) | (
(sizeof(pfioc_rule) & 0x1fff) << 16) | ((ord('D')) << 8) | (26))
DIOCBEGINADDRS = ((0x40000000 | 0x80000000) | (
(sizeof(pfioc_pooladdr) & 0x1fff) << 16) | ((ord('D')) << 8) | (51))
PF_CHANGE_ADD_TAIL = 2
PF_CHANGE_GET_TICKET = 6
PF_PASS = 0
PF_RDR = 8
PF_OUT = 2
_pf_fd = None
def pf_get_dev():
global _pf_fd
if _pf_fd is None:
_pf_fd = os.open('/dev/pf', os.O_RDWR)
return _pf_fd
def pf_query_nat(family, proto, src_ip, src_port, dst_ip, dst_port):
[proto, family, src_port, dst_port] = [
int(v) for v in [proto, family, src_port, dst_port]]
length = 4 if family == socket.AF_INET else 16
pnl = pfioc_natlook()
pnl.proto = proto
pnl.direction = PF_OUT
pnl.af = family
memmove(addressof(pnl.saddr), socket.inet_pton(pnl.af, src_ip), length)
pnl.sxport.port = socket.htons(src_port)
memmove(addressof(pnl.daddr), socket.inet_pton(pnl.af, dst_ip), length)
pnl.dxport.port = socket.htons(dst_port)
ioctl(pf_get_dev(), DIOCNATLOOK, (
c_char * sizeof(pnl)).from_address(addressof(pnl)))
ip = socket.inet_ntop(
pnl.af, (c_char * length).from_address(addressof(pnl.rdaddr)))
port = socket.ntohs(pnl.rdxport.port)
return (ip, port)
def pf_add_anchor_rule(type, name):
ACTION_OFFSET = 0
POOL_TICKET_OFFSET = 8
ANCHOR_CALL_OFFSET = 1040
RULE_ACTION_OFFSET = 3068
pr = pfioc_rule()
ppa = pfioc_pooladdr()
ioctl(pf_get_dev(), DIOCBEGINADDRS, ppa)
memmove(addressof(pr) + POOL_TICKET_OFFSET, ppa[4:8], 4) # pool_ticket
memmove(addressof(pr) + ANCHOR_CALL_OFFSET, name,
min(MAXPATHLEN, len(name))) # anchor_call = name
memmove(addressof(pr) + RULE_ACTION_OFFSET,
struct.pack('I', type), 4) # rule.action = type
memmove(addressof(pr) + ACTION_OFFSET, struct.pack(
'I', PF_CHANGE_GET_TICKET), 4) # action = PF_CHANGE_GET_TICKET
ioctl(pf_get_dev(), DIOCCHANGERULE, pr)
memmove(addressof(pr) + ACTION_OFFSET, struct.pack(
'I', PF_CHANGE_ADD_TAIL), 4) # action = PF_CHANGE_ADD_TAIL
ioctl(pf_get_dev(), DIOCCHANGERULE, pr)
# This is some voodoo for setting up the kernel's transparent
# proxying stuff. If subnets is empty, we just delete our sshuttle rules;
# otherwise we delete it, then make them from scratch.
......@@ -713,42 +59,14 @@ def pf_add_anchor_rule(type, name):
# exit. In case that fails, it's not the end of the world; future runs will
# supercede it in the transproxy list, at least, so the leftover rules
# are hopefully harmless.
def main(port_v6, port_v4,
dnsport_v6, dnsport_v4,
nslist, method, udp, syslog):
assert(port_v6 >= 0)
assert(port_v6 <= 65535)
assert(port_v4 >= 0)
assert(port_v4 <= 65535)
assert(dnsport_v6 >= 0)
assert(dnsport_v6 <= 65535)
assert(dnsport_v4 >= 0)
assert(dnsport_v4 <= 65535)
def main(method_name, syslog):
if os.getuid() != 0:
raise Fatal('you must be root (or enable su/sudo) to set the firewall')
if method == "auto":
if program_exists('ipfw'):
method = "ipfw"
elif program_exists('iptables'):
method = "nat"
elif program_exists('pfctl'):
method = "pf"
else:
raise Fatal(
"can't find either ipfw, iptables or pfctl; check your PATH")
if method == "nat":
do_it = do_iptables_nat
elif method == "tproxy":
do_it = do_iptables_tproxy
elif method == "ipfw":
do_it = do_ipfw
elif method == "pf":
do_it = do_pf
if method_name == "auto":
method = get_auto_method()
else:
raise Exception('Unknown method "%s"' % method)
method = get_method(method_name)
# because of limitations of the 'su' command, the *real* stdin/stdout
# are both attached to stdout initially. Clone stdout into stdin so we
......@@ -759,8 +77,8 @@ def main(port_v6, port_v4,
ssyslog.start_syslog()
ssyslog.stderr_to_syslog()
debug1('firewall manager ready method %s.\n' % method)
sys.stdout.write('READY %s\n' % method)
debug1('firewall manager ready method name %s.\n' % method.name)
sys.stdout.write('READY %s\n' % method.name)
sys.stdout.flush()
# don't disappear if our controlling terminal or stdout/stderr
......@@ -788,29 +106,80 @@ def main(port_v6, port_v4,
line = sys.stdin.readline(128)
if not line:
raise Fatal('firewall: expected route but got %r' % line)
elif line == 'GO\n':
elif line.startswith("NSLIST\n"):
break
try:
(family, width, exclude, ip) = line.strip().split(',', 3)
except:
raise Fatal('firewall: expected route or GO but got %r' % line)
raise Fatal('firewall: expected route or NSLIST but got %r' % line)
subnets.append((int(family), int(width), bool(int(exclude)), ip))
debug2('Got subnets: %r\n' % subnets)
nslist = []
if line != 'NSLIST\n':
raise Fatal('firewall: expected NSLIST but got %r' % line)
while 1:
line = sys.stdin.readline(128)
if not line:
raise Fatal('firewall: expected nslist but got %r' % line)
elif line.startswith("PORTS "):
break
try:
if line:
(family, ip) = line.strip().split(',', 1)
except:
raise Fatal('firewall: expected nslist or PORTS but got %r' % line)
nslist.append((int(family), ip))
debug2('Got partial nslist: %r\n' % nslist)
debug2('Got nslist: %r\n' % nslist)
if not line.startswith('PORTS '):
raise Fatal('firewall: expected PORTS but got %r' % line)
_, _, ports = line.partition(" ")
ports = ports.split(",")
if len(ports) != 4:
raise Fatal('firewall: expected 4 ports but got %n' % len(ports))
port_v6 = int(ports[0])
port_v4 = int(ports[1])
dnsport_v6 = int(ports[2])
dnsport_v4 = int(ports[3])
assert(port_v6 >= 0)
assert(port_v6 <= 65535)
assert(port_v4 >= 0)
assert(port_v4 <= 65535)
assert(dnsport_v6 >= 0)
assert(dnsport_v6 <= 65535)
assert(dnsport_v4 >= 0)
assert(dnsport_v4 <= 65535)
debug2('Got ports: %d,%d,%d,%d\n'
% (port_v6, port_v4, dnsport_v6, dnsport_v4))
line = sys.stdin.readline(128)
if not line:
raise Fatal('firewall: expected GO but got %r' % line)
elif not line.startswith("GO "):
raise Fatal('firewall: expected GO but got %r' % line)
_, _, udp = line.partition(" ")
udp = bool(int(udp))
debug2('Got udp: %r\n' % udp)
try:
do_wait = None
debug1('firewall manager: starting transproxy.\n')
subnets_v6 = [i for i in subnets if i[0] == socket.AF_INET6]
if port_v6:
do_wait = do_it(
if port_v6 > 0:
do_wait = method.setup_firewall(
port_v6, dnsport_v6, nslist,
socket.AF_INET6, subnets_v6, udp)
elif len(subnets_v6) > 0:
debug1("IPv6 subnets defined but IPv6 disabled\n")
subnets_v4 = [i for i in subnets if i[0] == socket.AF_INET]
if port_v4:
do_wait = do_it(
if port_v4 > 0:
do_wait = method.setup_firewall(
port_v4, dnsport_v4, nslist,
socket.AF_INET, subnets_v4, udp)
elif len(subnets_v4) > 0:
......@@ -836,15 +205,8 @@ def main(port_v6, port_v4,
(name, ip) = line[5:].strip().split(',', 1)
hostmap[name] = ip
rewrite_etc_hosts(port_v6 or port_v4)
elif line.startswith('QUERY_PF_NAT '):
try:
dst = pf_query_nat(*(line[13:].split(',')))
sys.stdout.write('QUERY_PF_NAT_SUCCESS %s,%r\n' % dst)
except IOError as e:
sys.stdout.write('QUERY_PF_NAT_FAILURE %s\n' % e)
sys.stdout.flush()
elif line:
if not method.firewall_command(line):
raise Fatal('expected EOF, got %r' % line)
else:
break
......@@ -854,7 +216,7 @@ def main(port_v6, port_v4,
except:
pass
if port_v6:
do_it(port_v6, 0, [], socket.AF_INET6, [], udp)
method.setup_firewall(port_v6, 0, [], socket.AF_INET6, [], udp)
if port_v4:
do_it(port_v4, 0, [], socket.AF_INET, [], udp)
method.setup_firewall(port_v4, 0, [], socket.AF_INET, [], udp)
restore_etc_hosts(port_v6 or port_v4)
sshuttle/linux.py 0 → 100644
View file @ ac723694
import socket
import subprocess as ssubprocess
from sshuttle.helpers import log, debug1, Fatal, family_to_string
def nonfatal(func, *args):
try:
func(*args)
except Fatal as e:
log('error: %s\n' % e)
def ipt_chain_exists(family, table, name):
if family == socket.AF_INET6:
cmd = 'ip6tables'
elif family == socket.AF_INET:
cmd = 'iptables'
else:
raise Exception('Unsupported family "%s"' % family_to_string(family))
argv = [cmd, '-t', table, '-nL']
p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE)
for line in p.stdout:
if line.startswith(b'Chain %s ' % name.encode("ASCII")):
return True
rv = p.wait()
if rv:
raise Fatal('%r returned %d' % (argv, rv))
def ipt(family, table, *args):
if family == socket.AF_INET6:
argv = ['ip6tables', '-t', table] + list(args)
elif family == socket.AF_INET:
argv = ['iptables', '-t', table] + list(args)
else:
raise Exception('Unsupported family "%s"' % family_to_string(family))
debug1('>> %s\n' % ' '.join(argv))
rv = ssubprocess.call(argv)
if rv:
raise Fatal('%r returned %d' % (argv, rv))
_no_ttl_module = False
def ipt_ttl(family, *args):
global _no_ttl_module
if not _no_ttl_module:
# we avoid infinite loops by generating server-side connections
# with ttl 42. This makes the client side not recapture those
# connections, in case client == server.
try:
argsplus = list(args) + ['-m', 'ttl', '!', '--ttl', '42']
ipt(family, *argsplus)
except Fatal:
ipt(family, *args)
# we only get here if the non-ttl attempt succeeds
log('sshuttle: warning: your iptables is missing '
'the ttl module.\n')
_no_ttl_module = True
else:
ipt(family, *args)
sshuttle/methods/__init__.py 0 → 100644
View file @ ac723694
import os
import importlib
import socket
import struct
import errno
from sshuttle.helpers import Fatal, debug3
def original_dst(sock):
try:
SO_ORIGINAL_DST = 80
SOCKADDR_MIN = 16
sockaddr_in = sock.getsockopt(socket.SOL_IP,
SO_ORIGINAL_DST, SOCKADDR_MIN)
(proto, port, a, b, c, d) = struct.unpack('!HHBBBB', sockaddr_in[:8])
assert(socket.htons(proto) == socket.AF_INET)
ip = '%d.%d.%d.%d' % (a, b, c, d)
return (ip, port)
except socket.error as e:
if e.args[0] == errno.ENOPROTOOPT:
return sock.getsockname()
raise
class Features(object):
pass
class BaseMethod(object):
def __init__(self, name):
self.name = name
def get_supported_features(self):
result = Features()
result.ipv6 = False
result.udp = False
return result
def get_tcp_dstip(self, sock):
return original_dst(sock)
def recv_udp(self, udp_listener, bufsize):
debug3('Accept UDP using recvfrom.\n')
data, srcip = udp_listener.recvfrom(bufsize)
return (srcip, None, data)
def send_udp(self, sock, srcip, dstip, data):
if srcip is not None:
Fatal("Method %s send_udp does not support setting srcip to %r"
% (self.name, srcip))
sock.sendto(data, dstip)
def setup_tcp_listener(self, tcp_listener):
pass
def setup_udp_listener(self, udp_listener):
pass
def check_settings(self, udp, dns):
if udp:
Fatal("UDP support not supported with method %s.\n" % self.name)
def setup_firewall(self, port, dnsport, nslist, family, subnets, udp):
raise NotImplementedError()
def firewall_command(self, line):
return False
def _program_exists(name):
paths = (os.getenv('PATH') or os.defpath).split(os.pathsep)
for p in paths:
fn = '%s/%s' % (p, name)
if os.path.exists(fn):
return not os.path.isdir(fn) and os.access(fn, os.X_OK)
def get_method(method_name):
module = importlib.import_module("sshuttle.methods.%s" % method_name)
return module.Method(method_name)
def get_auto_method():
if _program_exists('ipfw'):
method_name = "ipfw"
elif _program_exists('iptables'):
method_name = "nat"
elif _program_exists('pfctl'):
method_name = "pf"
else:
raise Fatal(
"can't find either ipfw, iptables or pfctl; check your PATH")
return get_method(method_name)
sshuttle/methods/ipfw.py 0 → 100644
View file @ ac723694
import sys
import select
import socket
import struct
import subprocess as ssubprocess
from sshuttle.helpers import log, debug1, debug3, islocal, \
Fatal, family_to_string
from sshuttle.methods import BaseMethod
# python doesn't have a definition for this
IPPROTO_DIVERT = 254
def ipfw_rule_exists(n):
argv = ['ipfw', 'list']
p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE)
found = False
for line in p.stdout:
if line.startswith('%05d ' % n):
if not ('ipttl 42' in line
or ('skipto %d' % (n + 1)) in line
or 'check-state' in line):
log('non-sshuttle ipfw rule: %r\n' % line.strip())
raise Fatal('non-sshuttle ipfw rule #%d already exists!' % n)
found = True
rv = p.wait()
if rv:
raise Fatal('%r returned %d' % (argv, rv))
return found
_oldctls = {}
def _fill_oldctls(prefix):
argv = ['sysctl', prefix]
p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE)
for line in p.stdout:
assert(line[-1] == '\n')
(k, v) = line[:-1].split(': ', 1)
_oldctls[k] = v
rv = p.wait()
if rv:
raise Fatal('%r returned %d' % (argv, rv))
if not line:
raise Fatal('%r returned no data' % (argv,))
def _sysctl_set(name, val):
argv = ['sysctl', '-w', '%s=%s' % (name, val)]
debug1('>> %s\n' % ' '.join(argv))
return ssubprocess.call(argv, stdout=open('/dev/null', 'w'))
_changedctls = []
def sysctl_set(name, val, permanent=False):
PREFIX = 'net.inet.ip'
assert(name.startswith(PREFIX + '.'))
val = str(val)
if not _oldctls:
_fill_oldctls(PREFIX)
if not (name in _oldctls):
debug1('>> No such sysctl: %r\n' % name)
return False
oldval = _oldctls[name]
if val != oldval:
rv = _sysctl_set(name, val)
if rv == 0 and permanent:
debug1('>> ...saving permanently in /etc/sysctl.conf\n')
f = open('/etc/sysctl.conf', 'a')
f.write('\n'
'# Added by sshuttle\n'
'%s=%s\n' % (name, val))
f.close()
else:
_changedctls.append(name)
return True
def _udp_unpack(p):
src = (socket.inet_ntoa(p[12:16]), struct.unpack('!H', p[20:22])[0])
dst = (socket.inet_ntoa(p[16:20]), struct.unpack('!H', p[22:24])[0])
return src, dst
def _udp_repack(p, src, dst):
addrs = socket.inet_aton(src[0]) + socket.inet_aton(dst[0])
ports = struct.pack('!HH', src[1], dst[1])
return p[:12] + addrs + ports + p[24:]
_real_dns_server = [None]
def _handle_diversion(divertsock, dnsport):
p, tag = divertsock.recvfrom(4096)
src, dst = _udp_unpack(p)
debug3('got diverted packet from %r to %r\n' % (src, dst))
if dst[1] == 53:
# outgoing DNS
debug3('...packet is a DNS request.\n')
_real_dns_server[0] = dst
dst = ('127.0.0.1', dnsport)
elif src[1] == dnsport:
if islocal(src[0], divertsock.family):
debug3('...packet is a DNS response.\n')
src = _real_dns_server[0]
else:
log('weird?! unexpected divert from %r to %r\n' % (src, dst))
assert(0)
newp = _udp_repack(p, src, dst)
divertsock.sendto(newp, tag)
def ipfw(*args):
argv = ['ipfw', '-q'] + list(args)
debug1('>> %s\n' % ' '.join(argv))
rv = ssubprocess.call(argv)
if rv:
raise Fatal('%r returned %d' % (argv, rv))
class Method(BaseMethod):
def setup_firewall(self, port, dnsport, nslist, family, subnets, udp):
# IPv6 not supported
if family not in [socket.AF_INET, ]:
raise Exception(
'Address family "%s" unsupported by ipfw method_name'
% family_to_string(family))
if udp:
raise Exception("UDP not supported by ipfw method_name")
sport = str(port)
xsport = str(port + 1)
# cleanup any existing rules
if ipfw_rule_exists(port):
ipfw('delete', sport)
while _changedctls:
name = _changedctls.pop()
oldval = _oldctls[name]
_sysctl_set(name, oldval)
if subnets or dnsport:
sysctl_set('net.inet.ip.fw.enable', 1)
changed = sysctl_set('net.inet.ip.scopedroute', 0, permanent=True)
if changed:
log("\n"
" WARNING: ONE-TIME NETWORK DISRUPTION:\n"
" =====================================\n"
"sshuttle has changed a MacOS kernel setting to work around\n"
"a bug in MacOS 10.6. This will cause your network to drop\n"
"within 5-10 minutes unless you restart your network\n"
"interface (change wireless networks or unplug/plug the\n"
"ethernet port) NOW, then restart sshuttle. The fix is\n"
"permanent; you only have to do this once.\n\n")
sys.exit(1)
ipfw('add', sport, 'check-state', 'ip',
'from', 'any', 'to', 'any')
if subnets:
# create new subnet entries
for f, swidth, sexclude, snet \
in sorted(subnets, key=lambda s: s[1], reverse=True):
if sexclude:
ipfw('add', sport, 'skipto', xsport,
'tcp',
'from', 'any', 'to', '%s/%s' % (snet, swidth))
else:
ipfw('add', sport, 'fwd', '127.0.0.1,%d' % port,
'tcp',
'from', 'any', 'to', '%s/%s' % (snet, swidth),
'not', 'ipttl', '42', 'keep-state', 'setup')
# This part is much crazier than it is on Linux, because MacOS (at
# least 10.6, and probably other versions, and maybe FreeBSD too)
# doesn't correctly fixup the dstip/dstport for UDP packets when it
# puts them through a 'fwd' rule. It also doesn't fixup the
# srcip/srcport in the response packet. In Linux iptables, all that
# happens magically for us, so we just redirect the packets and relax.
#
# On MacOS, we have to fix the ports ourselves. For that, we use a
# 'divert' socket, which receives raw packets and lets us mangle them.
#
# Here's how it works. Let's say the local DNS server is 1.1.1.1:53,
# and the remote DNS server is 2.2.2.2:53, and the local transproxy
# port is 10.0.0.1:12300, and a client machine is making a request from
# 10.0.0.5:9999. We see a packet like this:
# 10.0.0.5:9999 -> 1.1.1.1:53
# Since the destip:port matches one of our local nameservers, it will
# match a 'fwd' rule, thus grabbing it on the local machine. However,
# the local kernel will then see a packet addressed to *:53 and not
# know what to do with it; there's nobody listening on port 53. Thus,
# we divert it, rewriting it into this:
# 10.0.0.5:9999 -> 10.0.0.1:12300
# This gets proxied out to the server, which sends it to 2.2.2.2:53,
# and the answer comes back, and the proxy sends it back out like this:
# 10.0.0.1:12300 -> 10.0.0.5:9999
# But that's wrong! The original machine expected an answer from
# 1.1.1.1:53, so we have to divert the *answer* and rewrite it:
# 1.1.1.1:53 -> 10.0.0.5:9999
#
# See? Easy stuff.
if dnsport:
divertsock = socket.socket(socket.AF_INET, socket.SOCK_RAW,
IPPROTO_DIVERT)
divertsock.bind(('0.0.0.0', port)) # IP field is ignored
for f, ip in [i for i in nslist if i[0] == family]:
# relabel and then catch outgoing DNS requests
ipfw('add', sport, 'divert', sport,
'udp',
'from', 'any', 'to', '%s/32' % ip, '53',
'not', 'ipttl', '42')
# relabel DNS responses
ipfw('add', sport, 'divert', sport,
'udp',
'from', 'any', str(dnsport), 'to', 'any',
'not', 'ipttl', '42')
def do_wait():
while 1:
r, w, x = select.select([sys.stdin, divertsock], [], [])
if divertsock in r:
_handle_diversion(divertsock, dnsport)
if sys.stdin in r:
return
else:
do_wait = None
return do_wait
sshuttle/methods/nat.py 0 → 100644
View file @ ac723694
import socket
from sshuttle.helpers import family_to_string
from sshuttle.linux import ipt, ipt_ttl, ipt_chain_exists, nonfatal
from sshuttle.methods import BaseMethod
class Method(BaseMethod):
# We name the chain based on the transproxy port number so that it's
# possible to run multiple copies of sshuttle at the same time. Of course,
# the multiple copies shouldn't have overlapping subnets, or only the most-
# recently-started one will win (because we use "-I OUTPUT 1" instead of
# "-A OUTPUT").
def setup_firewall(self, port, dnsport, nslist, family, subnets, udp):
# only ipv4 supported with NAT
if family != socket.AF_INET:
raise Exception(
'Address family "%s" unsupported by nat method_name'
% family_to_string(family))
if udp:
raise Exception("UDP not supported by nat method_name")
table = "nat"
def _ipt(*args):
return ipt(family, table, *args)
def _ipt_ttl(*args):
return ipt_ttl(family, table, *args)
chain = 'sshuttle-%s' % port
# basic cleanup/setup of chains
if ipt_chain_exists(family, table, chain):
nonfatal(_ipt, '-D', 'OUTPUT', '-j', chain)
nonfatal(_ipt, '-D', 'PREROUTING', '-j', chain)
nonfatal(_ipt, '-F', chain)
_ipt('-X', chain)
if subnets or dnsport:
_ipt('-N', chain)
_ipt('-F', chain)
_ipt('-I', 'OUTPUT', '1', '-j', chain)
_ipt('-I', 'PREROUTING', '1', '-j', chain)
if subnets:
# create new subnet entries. Note that we're sorting in a very
# particular order: we need to go from most-specific (largest
# swidth) to least-specific, and at any given level of specificity,
# we want excludes to come first. That's why the columns are in
# such a non- intuitive order.
for f, swidth, sexclude, snet \
in sorted(subnets, key=lambda s: s[1], reverse=True):
if sexclude:
_ipt('-A', chain, '-j', 'RETURN',
'--dest', '%s/%s' % (snet, swidth),
'-p', 'tcp')
else:
_ipt_ttl('-A', chain, '-j', 'REDIRECT',
'--dest', '%s/%s' % (snet, swidth),
'-p', 'tcp',
'--to-ports', str(port))
if dnsport:
for f, ip in [i for i in nslist if i[0] == family]:
_ipt_ttl('-A', chain, '-j', 'REDIRECT',
'--dest', '%s/32' % ip,
'-p', 'udp',
'--dport', '53',
'--to-ports', str(dnsport))
sshuttle/methods/pf.py 0 → 100644
View file @ ac723694
import os
import sys
import re
import socket
import struct
import subprocess as ssubprocess
from fcntl import ioctl
from ctypes import c_char, c_uint8, c_uint16, c_uint32, Union, Structure, \
sizeof, addressof, memmove
from sshuttle.helpers import debug1, debug2, Fatal
from sshuttle.methods import BaseMethod
def pfctl(args, stdin=None):
argv = ['pfctl'] + list(args.split(" "))
debug1('>> %s\n' % ' '.join(argv))
p = ssubprocess.Popen(argv, stdin=ssubprocess.PIPE,
stdout=ssubprocess.PIPE,
stderr=ssubprocess.PIPE)
o = p.communicate(stdin)
if p.returncode:
raise Fatal('%r returned %d' % (argv, p.returncode))
return o
_pf_context = {'started_by_sshuttle': False, 'Xtoken': ''}
# This are some classes and functions used to support pf in yosemite.
class pf_state_xport(Union):
_fields_ = [("port", c_uint16),
("call_id", c_uint16),
("spi", c_uint32)]
class pf_addr(Structure):
class _pfa(Union):
_fields_ = [("v4", c_uint32), # struct in_addr
("v6", c_uint32 * 4), # struct in6_addr
("addr8", c_uint8 * 16),
("addr16", c_uint16 * 8),
("addr32", c_uint32 * 4)]
_fields_ = [("pfa", _pfa)]
_anonymous_ = ("pfa",)
class pfioc_natlook(Structure):
_fields_ = [("saddr", pf_addr),
("daddr", pf_addr),
("rsaddr", pf_addr),
("rdaddr", pf_addr),
("sxport", pf_state_xport),
("dxport", pf_state_xport),
("rsxport", pf_state_xport),
("rdxport", pf_state_xport),
("af", c_uint8), # sa_family_t
("proto", c_uint8),
("proto_variant", c_uint8),
("direction", c_uint8)]
pfioc_rule = c_char * 3104 # sizeof(struct pfioc_rule)
pfioc_pooladdr = c_char * 1136 # sizeof(struct pfioc_pooladdr)
MAXPATHLEN = 1024
DIOCNATLOOK = ((0x40000000 | 0x80000000) | (
(sizeof(pfioc_natlook) & 0x1fff) << 16) | ((ord('D')) << 8) | (23))
DIOCCHANGERULE = ((0x40000000 | 0x80000000) | (
(sizeof(pfioc_rule) & 0x1fff) << 16) | ((ord('D')) << 8) | (26))
DIOCBEGINADDRS = ((0x40000000 | 0x80000000) | (
(sizeof(pfioc_pooladdr) & 0x1fff) << 16) | ((ord('D')) << 8) | (51))
PF_CHANGE_ADD_TAIL = 2
PF_CHANGE_GET_TICKET = 6
PF_PASS = 0
PF_RDR = 8
PF_OUT = 2
_pf_fd = None
def pf_get_dev():
global _pf_fd
if _pf_fd is None:
_pf_fd = os.open('/dev/pf', os.O_RDWR)
return _pf_fd
def pf_query_nat(family, proto, src_ip, src_port, dst_ip, dst_port):
[proto, family, src_port, dst_port] = [
int(v) for v in [proto, family, src_port, dst_port]]
length = 4 if family == socket.AF_INET else 16
pnl = pfioc_natlook()
pnl.proto = proto
pnl.direction = PF_OUT
pnl.af = family
memmove(addressof(pnl.saddr), socket.inet_pton(pnl.af, src_ip), length)
pnl.sxport.port = socket.htons(src_port)
memmove(addressof(pnl.daddr), socket.inet_pton(pnl.af, dst_ip), length)
pnl.dxport.port = socket.htons(dst_port)
ioctl(pf_get_dev(), DIOCNATLOOK, (
c_char * sizeof(pnl)).from_address(addressof(pnl)))
ip = socket.inet_ntop(
pnl.af, (c_char * length).from_address(addressof(pnl.rdaddr)))
port = socket.ntohs(pnl.rdxport.port)
return (ip, port)
def pf_add_anchor_rule(type, name):
ACTION_OFFSET = 0
POOL_TICKET_OFFSET = 8
ANCHOR_CALL_OFFSET = 1040
RULE_ACTION_OFFSET = 3068
pr = pfioc_rule()
ppa = pfioc_pooladdr()
ioctl(pf_get_dev(), DIOCBEGINADDRS, ppa)
memmove(addressof(pr) + POOL_TICKET_OFFSET, ppa[4:8], 4) # pool_ticket
memmove(addressof(pr) + ANCHOR_CALL_OFFSET, name,
min(MAXPATHLEN, len(name))) # anchor_call = name
memmove(addressof(pr) + RULE_ACTION_OFFSET,
struct.pack('I', type), 4) # rule.action = type
memmove(addressof(pr) + ACTION_OFFSET, struct.pack(
'I', PF_CHANGE_GET_TICKET), 4) # action = PF_CHANGE_GET_TICKET
ioctl(pf_get_dev(), DIOCCHANGERULE, pr)
memmove(addressof(pr) + ACTION_OFFSET, struct.pack(
'I', PF_CHANGE_ADD_TAIL), 4) # action = PF_CHANGE_ADD_TAIL
ioctl(pf_get_dev(), DIOCCHANGERULE, pr)
class Method(BaseMethod):
def get_tcp_dstip(self, sock):
# yuck
from sshuttle.client import firewall
peer = sock.getpeername()
proxy = sock.getsockname()
argv = (sock.family, socket.IPPROTO_TCP,
peer[0], peer[1], proxy[0], proxy[1])
firewall.pfile.write("QUERY_PF_NAT %r,%r,%s,%r,%s,%r\n" % argv)
firewall.pfile.flush()
line = firewall.pfile.readline()
debug2("QUERY_PF_NAT %r,%r,%s,%r,%s,%r" % argv + ' > ' + line)
if line.startswith('QUERY_PF_NAT_SUCCESS '):
(ip, port) = line[21:].split(',')
return (ip, int(port))
return sock.getsockname()
def setup_firewall(self, port, dnsport, nslist, family, subnets, udp):
global _pf_started_by_sshuttle
tables = []
translating_rules = []
filtering_rules = []
if subnets:
includes = []
# If a given subnet is both included and excluded, list the
# exclusion first; the table will ignore the second, opposite
# definition
for f, swidth, sexclude, snet in sorted(
subnets, key=lambda s: (s[1], s[2]), reverse=True):
includes.append("%s%s/%s" %
("!" if sexclude else "", snet, swidth))
tables.append('table <forward_subnets> {%s}' % ','.join(includes))
translating_rules.append(
'rdr pass on lo0 proto tcp '
'to <forward_subnets> -> 127.0.0.1 port %r' % port)
filtering_rules.append(
'pass out route-to lo0 inet proto tcp '
'to <forward_subnets> keep state')
if dnsport:
tables.append('table <dns_servers> {%s}' % ','.join(
[ns[1] for ns in nslist]))
translating_rules.append(
'rdr pass on lo0 proto udp to '
'<dns_servers> port 53 -> 127.0.0.1 port %r' % dnsport)
filtering_rules.append(
'pass out route-to lo0 inet proto udp to '
'<dns_servers> port 53 keep state')
rules = '\n'.join(tables + translating_rules + filtering_rules) \
+ '\n'
pf_status = pfctl('-s all')[0]
if '\nrdr-anchor "sshuttle" all\n' not in pf_status:
pf_add_anchor_rule(PF_RDR, "sshuttle")
if '\nanchor "sshuttle" all\n' not in pf_status:
pf_add_anchor_rule(PF_PASS, "sshuttle")
pfctl('-a sshuttle -f /dev/stdin', rules)
if sys.platform == "darwin":
o = pfctl('-E')
_pf_context['Xtoken'] = \
re.search(r'Token : (.+)', o[1]).group(1)
elif 'INFO:\nStatus: Disabled' in pf_status:
pfctl('-e')
_pf_context['started_by_sshuttle'] = True
else:
pfctl('-a sshuttle -F all')
if sys.platform == "darwin":
pfctl('-X %s' % _pf_context['Xtoken'])
elif _pf_context['started_by_sshuttle']:
pfctl('-d')
def firewall_command(self, line):
if line.startswith('QUERY_PF_NAT '):
try:
dst = pf_query_nat(*(line[13:].split(',')))
sys.stdout.write('QUERY_PF_NAT_SUCCESS %s,%r\n' % dst)
except IOError as e:
sys.stdout.write('QUERY_PF_NAT_FAILURE %s\n' % e)
sys.stdout.flush()
return True
else:
return False
sshuttle/methods/tproxy.py 0 → 100644
View file @ ac723694
import struct
from sshuttle.helpers import family_to_string
from sshuttle.linux import ipt, ipt_ttl, ipt_chain_exists
from sshuttle.methods import BaseMethod
from sshuttle.helpers import debug1, debug3, Fatal
recvmsg = None
try:
# try getting recvmsg from python
import socket as pythonsocket
getattr(pythonsocket.socket, "recvmsg")
socket = pythonsocket
recvmsg = "python"
except AttributeError:
# try getting recvmsg from socket_ext library
try:
import socket_ext
getattr(socket_ext.socket, "recvmsg")
socket = socket_ext
recvmsg = "socket_ext"
except ImportError:
import socket
IP_TRANSPARENT = 19
IP_ORIGDSTADDR = 20
IP_RECVORIGDSTADDR = IP_ORIGDSTADDR
SOL_IPV6 = 41
IPV6_ORIGDSTADDR = 74
IPV6_RECVORIGDSTADDR = IPV6_ORIGDSTADDR
if recvmsg == "python":
def recv_udp(listener, bufsize):
debug3('Accept UDP python using recvmsg.\n')
data, ancdata, msg_flags, srcip = listener.recvmsg(
4096, socket.CMSG_SPACE(24))
dstip = None
family = None
for cmsg_level, cmsg_type, cmsg_data in ancdata:
if cmsg_level == socket.SOL_IP and cmsg_type == IP_ORIGDSTADDR:
family, port = struct.unpack('=HH', cmsg_data[0:4])
port = socket.htons(port)
if family == socket.AF_INET:
start = 4
length = 4
else:
raise Fatal("Unsupported socket type '%s'" % family)
ip = socket.inet_ntop(family, cmsg_data[start:start + length])
dstip = (ip, port)
break
elif cmsg_level == SOL_IPV6 and cmsg_type == IPV6_ORIGDSTADDR:
family, port = struct.unpack('=HH', cmsg_data[0:4])
port = socket.htons(port)
if family == socket.AF_INET6:
start = 8
length = 16
else:
raise Fatal("Unsupported socket type '%s'" % family)
ip = socket.inet_ntop(family, cmsg_data[start:start + length])
dstip = (ip, port)
break
return (srcip, dstip, data)
elif recvmsg == "socket_ext":
def recv_udp(listener, bufsize):
debug3('Accept UDP using socket_ext recvmsg.\n')
srcip, data, adata, flags = listener.recvmsg(
(bufsize,), socket.CMSG_SPACE(24))
dstip = None
family = None
for a in adata:
if a.cmsg_level == socket.SOL_IP and a.cmsg_type == IP_ORIGDSTADDR:
family, port = struct.unpack('=HH', a.cmsg_data[0:4])
port = socket.htons(port)
if family == socket.AF_INET:
start = 4
length = 4
else:
raise Fatal("Unsupported socket type '%s'" % family)
ip = socket.inet_ntop(
family, a.cmsg_data[start:start + length])
dstip = (ip, port)
break
elif a.cmsg_level == SOL_IPV6 and a.cmsg_type == IPV6_ORIGDSTADDR:
family, port = struct.unpack('=HH', a.cmsg_data[0:4])
port = socket.htons(port)
if family == socket.AF_INET6:
start = 8
length = 16
else:
raise Fatal("Unsupported socket type '%s'" % family)
ip = socket.inet_ntop(
family, a.cmsg_data[start:start + length])
dstip = (ip, port)
break
return (srcip, dstip, data[0])
else:
def recv_udp(listener, bufsize):
debug3('Accept UDP using recvfrom.\n')
data, srcip = listener.recvfrom(bufsize)
return (srcip, None, data)
class Method(BaseMethod):
def get_supported_features(self):
result = super(Method, self).get_supported_features()
result.ipv6 = True
result.udp = True
return result
def get_tcp_dstip(self, sock):
return sock.getsockname()
def recv_udp(self, udp_listener, bufsize):
srcip, dstip, data = recv_udp(udp_listener, bufsize)
if not dstip:
debug1(
"-- ignored UDP from %r: "
"couldn't determine destination IP address\n" % (srcip,))
return None
return None
def send_udp(self, sock, srcip, dstip, data):
sender = socket.socket(sock.family, socket.SOCK_DGRAM)
sender.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sender.setsockopt(socket.SOL_IP, IP_TRANSPARENT, 1)
sender.bind(srcip)
sender.sendto(data, dstip)
sender.close()
def setup_tcp_listener(self, tcp_listener):
tcp_listener.setsockopt(socket.SOL_IP, IP_TRANSPARENT, 1)
def setup_udp_listener(self, udp_listener):
udp_listener.setsockopt(socket.SOL_IP, IP_TRANSPARENT, 1)
if udp_listener.v4 is not None:
udp_listener.v4.setsockopt(
socket.SOL_IP, IP_RECVORIGDSTADDR, 1)
if udp_listener.v6 is not None:
udp_listener.v6.setsockopt(SOL_IPV6, IPV6_RECVORIGDSTADDR, 1)
def setup_firewall(self, port, dnsport, nslist, family, subnets, udp):
if family not in [socket.AF_INET, socket.AF_INET6]:
raise Exception(
'Address family "%s" unsupported by tproxy method'
% family_to_string(family))
table = "mangle"
def _ipt(*args):
return ipt(family, table, *args)
def _ipt_ttl(*args):
return ipt_ttl(family, table, *args)
mark_chain = 'sshuttle-m-%s' % port
tproxy_chain = 'sshuttle-t-%s' % port
divert_chain = 'sshuttle-d-%s' % port
# basic cleanup/setup of chains
if ipt_chain_exists(family, table, mark_chain):
_ipt('-D', 'OUTPUT', '-j', mark_chain)
_ipt('-F', mark_chain)
_ipt('-X', mark_chain)
if ipt_chain_exists(family, table, tproxy_chain):
_ipt('-D', 'PREROUTING', '-j', tproxy_chain)
_ipt('-F', tproxy_chain)
_ipt('-X', tproxy_chain)
if ipt_chain_exists(family, table, divert_chain):
_ipt('-F', divert_chain)
_ipt('-X', divert_chain)
if subnets or dnsport:
_ipt('-N', mark_chain)
_ipt('-F', mark_chain)
_ipt('-N', divert_chain)
_ipt('-F', divert_chain)
_ipt('-N', tproxy_chain)
_ipt('-F', tproxy_chain)
_ipt('-I', 'OUTPUT', '1', '-j', mark_chain)
_ipt('-I', 'PREROUTING', '1', '-j', tproxy_chain)
_ipt('-A', divert_chain, '-j', 'MARK', '--set-mark', '1')
_ipt('-A', divert_chain, '-j', 'ACCEPT')
_ipt('-A', tproxy_chain, '-m', 'socket', '-j', divert_chain,
'-m', 'tcp', '-p', 'tcp')
if subnets and udp:
_ipt('-A', tproxy_chain, '-m', 'socket', '-j', divert_chain,
'-m', 'udp', '-p', 'udp')
if dnsport:
for f, ip in [i for i in nslist if i[0] == family]:
_ipt('-A', mark_chain, '-j', 'MARK', '--set-mark', '1',
'--dest', '%s/32' % ip,
'-m', 'udp', '-p', 'udp', '--dport', '53')
_ipt('-A', tproxy_chain, '-j', 'TPROXY',
'--tproxy-mark', '0x1/0x1',
'--dest', '%s/32' % ip,
'-m', 'udp', '-p', 'udp', '--dport', '53',
'--on-port', str(dnsport))
if subnets:
for f, swidth, sexclude, snet \
in sorted(subnets, key=lambda s: s[1], reverse=True):
if sexclude:
_ipt('-A', mark_chain, '-j', 'RETURN',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'tcp', '-p', 'tcp')
_ipt('-A', tproxy_chain, '-j', 'RETURN',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'tcp', '-p', 'tcp')
else:
_ipt('-A', mark_chain, '-j', 'MARK',
'--set-mark', '1',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'tcp', '-p', 'tcp')
_ipt('-A', tproxy_chain, '-j', 'TPROXY',
'--tproxy-mark', '0x1/0x1',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'tcp', '-p', 'tcp',
'--on-port', str(port))
if sexclude and udp:
_ipt('-A', mark_chain, '-j', 'RETURN',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'udp', '-p', 'udp')
_ipt('-A', tproxy_chain, '-j', 'RETURN',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'udp', '-p', 'udp')
elif udp:
_ipt('-A', mark_chain, '-j', 'MARK',
'--set-mark', '1',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'udp', '-p', 'udp')
_ipt('-A', tproxy_chain, '-j', 'TPROXY',
'--tproxy-mark', '0x1/0x1',
'--dest', '%s/%s' % (snet, swidth),
'-m', 'udp', '-p', 'udp',
'--on-port', str(port))
def check_settings(self, udp, dns):
if udp and recvmsg is None:
Fatal("tproxy UDP support requires recvmsg function.\n")
if dns and recvmsg is None:
Fatal("tproxy DNS support requires recvmsg function.\n")
if dns:
debug1("tproxy UDP support enabled.\n")
if udp:
debug1("tproxy DNS support enabled.\n")
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