remote.py

import socket
import socks

from pwnlib.log import getLogger
from pwnlib.timeout import Timeout
from pwnlib.tubes.sock import sock

log = getLogger(__name__)

class remote(sock):
    r"""Creates a TCP or UDP-connection to a remote host. It supports
    both IPv4 and IPv6.

    The returned object supports all the methods from
    :class:`pwnlib.tubes.sock` and :class:`pwnlib.tubes.tube`.

    Arguments:
        host(str): The host to connect to.
        port(int): The port to connect to.
        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`.
        timeout: A positive number, None or the string "default".
        sock(:class:`socket.socket`): Socket to inherit, rather than connecting
        ssl(bool): Wrap the socket with SSL
        ssl_context(ssl.SSLContext): Specify SSLContext used to wrap the socket.
        ssl_args(dict): Pass :func:`ssl.wrap_socket` named arguments in a dictionary.
        sni(str,bool): Set 'server_hostname' in ssl_args. Set to True to set it based on the host argument. Set to False to not provide any value. Default is True.

    Examples:

        >>> r = remote('google.com', 443, ssl=True)
        >>> r.send(b'GET /\r\n\r\n')
        >>> r.recvn(4)
        b'HTTP'

        If a connection cannot be made, an exception is raised.

        >>> r = remote('127.0.0.1', 1)
        Traceback (most recent call last):
        ...
        PwnlibException: Could not connect to 127.0.0.1 on port 1

        You can also use :meth:`.remote.fromsocket` to wrap an existing socket.

        >>> import socket
        >>> s = socket.socket()
        >>> s.connect(('google.com', 80))
        >>> s.send(b'GET /' + b'\r\n'*2)
        9
        >>> r = remote.fromsocket(s)
        >>> r.recvn(4)
        b'HTTP'
        >>> s = socket.socket(socket.AF_INET6, socket.SOCK_STREAM) #doctest: +SKIP
        >>> s.connect(('2606:4700:4700::1111', 80)) #doctest: +SKIP
        >>> s.send(b'GET ' + b'\r\n'*2) #doctest: +SKIP
        8
        >>> r = remote.fromsocket(s) #doctest: +SKIP
        >>> r.recvn(4) #doctest: +SKIP
        b'HTTP'
    """

    def __init__(self, host, port,
                 fam = "any", typ = "tcp",
                 sock=None, ssl=False, ssl_context=None, ssl_args=None, sni=True,
                 *args, **kwargs):
        super(remote, self).__init__(*args, **kwargs)

        # convert port to string for sagemath support
        self.rport  = str(port)
        self.rhost  = host

        if sock:
            self.family = sock.family
            self.type   = sock.type
            self.proto  = sock.proto
            self.sock   = sock

        else:
            typ = self._get_type(typ)
            fam = self._get_family(fam)
            try:
                self.sock   = self._connect(fam, typ)
            except socket.gaierror as e:
                if e.errno != socket.EAI_NONAME:
                    raise
                self.exception('Could not resolve hostname: %r', host)
        if self.sock:
            self.settimeout(self.timeout)
            self.lhost, self.lport = self.sock.getsockname()[:2]

            if ssl:
                # Deferred import to save startup time
                import ssl as _ssl

                ssl_args = ssl_args or {}
                if "server_hostname" in ssl_args and sni:
                    log.error("sni and server_hostname cannot be set at the same time")
                ssl_context = ssl_context or _ssl.SSLContext(_ssl.PROTOCOL_TLS_CLIENT)
                if isinstance(sni, str):
                    ssl_args["server_hostname"] = sni
                elif sni:
                    ssl_args["server_hostname"] = host
                self.sock = ssl_context.wrap_socket(self.sock,**ssl_args)

    def _connect(self, fam, typ):
        sock    = None
        timeout = self.timeout

        with self.waitfor('Opening connection to %s on port %s' % (self.rhost, self.rport)) as h:
            for res in socket.getaddrinfo(self.rhost, self.rport, fam, typ, 0, socket.AI_PASSIVE):
                self.family, self.type, self.proto, _canonname, sockaddr = res

                if self.type not in [socket.SOCK_STREAM, socket.SOCK_DGRAM]:
                    continue

                h.status("Trying %s", sockaddr[0])

                sock = socket.socket(self.family, self.type, self.proto)

                if timeout is not None and timeout <= 0:
                    sock.setblocking(0)
                else:
                    sock.setblocking(1)
                    sock.settimeout(timeout)

                try:
                    sock.connect(sockaddr)
                    return sock
                except socks.ProxyError:
                    raise
                except socket.error:
                    pass
            self.error("Could not connect to %s on port %s", self.rhost, self.rport)

    @classmethod
    def fromsocket(cls, socket):
        """
        Helper method to wrap a standard python socket.socket with the
        tube APIs.

        Arguments:
            socket: Instance of socket.socket

        Returns:
            Instance of pwnlib.tubes.remote.remote.
        """
        s = socket
        host, port = s.getpeername()[:2]
        return remote(host, port, fam=s.family, typ=s.type, sock=s)

class tcp(remote):
    __doc__ = remote.__doc__
    def __init__(self, host, port, *a, **kw):
        return super(tcp, self).__init__(host, port, typ="tcp", *a, **kw)

class udp(remote):
    __doc__ = remote.__doc__
    def __init__(self, host, port, *a, **kw):
        return super(udp, self).__init__(host, port, typ="udp", *a, **kw)

class connect(remote):
    __doc__ = remote.__doc__