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from __future__ import absolute_import
from __future__ import division
import errno
import socket
from pwnlib.context import context
from pwnlib.log import getLogger
from pwnlib.timeout import Timeout
from pwnlib.tubes.sock import sock
log = getLogger(__name__)
class listen(sock):
r"""Creates an TCP or UDP-socket to receive data on. It supports
both IPv4 and IPv6. You need to call :meth:`wait_for_connection`
before using the listen socket.
The returned object supports all the methods from
:class:`pwnlib.tubes.sock` and :class:`pwnlib.tubes.tube`.
Arguments:
port(int): The port to connect to.
Defaults to a port auto-selected by the operating system.
bindaddr(str): The address to bind to.
Defaults to ``0.0.0.0`` / `::`.
fam: The string "any", "ipv4" or "ipv6" or an integer to pass to :func:`socket.getaddrinfo`.
typ: The string "tcp" or "udp" or an integer to pass to :func:`socket.getaddrinfo`.
Examples:
>>> l = listen(1234)
>>> r = remote('localhost', l.lport)
>>> _ = l.wait_for_connection()
>>> l.sendline(b'Hello')
>>> r.recvline()
b'Hello\n'
>>> # It works with ipv4 by default
>>> l = listen()
>>> l.spawn_process('/bin/sh')
>>> r = remote('127.0.0.1', l.lport)
>>> r.sendline(b'echo Goodbye')
>>> r.recvline()
b'Goodbye\n'
>>> # and it works with ipv6 by defaut, too!
>>> l = listen()
>>> r = remote('::1', l.lport)
>>> _ = l.wait_for_connection()
>>> r.sendline(b'Bye-bye')
>>> l.recvline()
b'Bye-bye\n'
"""
#: Local port
lport = 0
#: Local host
lhost = None
#: Socket type (e.g. socket.SOCK_STREAM)
type = None
#: Socket family
family = None
#: Socket protocol
protocol = None
#: Canonical name of the listening interface
canonname = None
#: Sockaddr structure that is being listened on
sockaddr = None
_accepter = None
def __init__(self, port=0, bindaddr='::',
fam='any', typ='tcp', *args, **kwargs):
super(listen, self).__init__(*args, **kwargs)
# convert port to string for sagemath support
port = str(port)
fam = self._get_family(fam)
typ = self._get_type(typ)
if fam == socket.AF_INET and bindaddr == '::':
bindaddr = '0.0.0.0'
h = self.waitfor('Trying to bind to %s on port %s' % (bindaddr, port))
for res in socket.getaddrinfo(bindaddr, port, fam, typ, 0, socket.AI_PASSIVE):
self.family, self.type, self.proto, self.canonname, self.sockaddr = res
if self.type not in [socket.SOCK_STREAM, socket.SOCK_DGRAM]:
continue
h.status("Trying %s" % self.sockaddr[0])
listen_sock = socket.socket(self.family, self.type, self.proto)
listen_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
if self.family == socket.AF_INET6:
try:
listen_sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, fam == socket.AF_INET6)
except (socket.error, AttributeError):
self.warn("could not set socket to accept also IPV4")
listen_sock.bind(self.sockaddr)
self.lhost, self.lport = listen_sock.getsockname()[:2]
if self.type == socket.SOCK_STREAM:
listen_sock.listen(1)
break
else:
h.failure()
self.error("Could not bind to %s on port %s" % (bindaddr, port))
h.success()
h = self.waitfor('Waiting for connections on %s:%s' % (self.lhost, self.lport))
def accepter():
while True:
try:
if self.type == socket.SOCK_STREAM:
self.sock, rhost = listen_sock.accept()
listen_sock.close()
else:
data, rhost = listen_sock.recvfrom(4096)
listen_sock.connect(rhost)
self.sock = listen_sock
self.unrecv(data)
self.settimeout(self.timeout)
break
except socket.error as e:
if e.errno == errno.EINTR:
continue
h.failure()
self.exception("Socket failure while waiting for connection")
self.sock = None
return
self.rhost, self.rport = rhost[:2]
h.success('Got connection from %s on port %d' % (self.rhost, self.rport))
self._accepter = context.Thread(target = accepter)
self._accepter.daemon = True
self._accepter.start()
def spawn_process(self, *args, **kwargs):
def accepter():
self.wait_for_connection()
self.sock.setblocking(1)
p = super(listen, self).spawn_process(*args, **kwargs)
p.wait()
self.close()
t = context.Thread(target = accepter)
t.daemon = True
t.start()
def wait_for_connection(self):
"""Blocks until a connection has been established."""
self.sock
return self
@property
def sock(self):
try:
return self.__dict__['sock']
except KeyError:
pass
self._accepter.join(timeout=self.timeout)
return self.__dict__.get('sock')
@sock.setter
def sock(self, s):
self.__dict__['sock'] = s
def close(self):
# since `close` is scheduled to run on exit we must check that we got
# a connection or the program will hang in the `join` call above
if self._accepter and self._accepter.is_alive():
return
super(listen, self).close()
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