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681 lines
24 KiB
Python
681 lines
24 KiB
Python
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# Copyright (C) 2003-2007 Robey Pointer <robeypointer@gmail.com>
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# Copyright (C) 2013-2014 science + computing ag
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# Author: Sebastian Deiss <sebastian.deiss@t-online.de>
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#
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#
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# This file is part of paramiko.
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#
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# Paramiko is free software; you can redistribute it and/or modify it under the
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# terms of the GNU Lesser General Public License as published by the Free
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# Software Foundation; either version 2.1 of the License, or (at your option)
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# any later version.
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#
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# Paramiko is distributed in the hope that it will be useful, but WITHOUT ANY
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# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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# A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
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# details.
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#
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# You should have received a copy of the GNU Lesser General Public License
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# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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"""
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This module provides GSS-API / SSPI Key Exchange as defined in :rfc:`4462`.
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.. note:: Credential delegation is not supported in server mode.
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.. note::
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`RFC 4462 Section 2.2
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<https://tools.ietf.org/html/rfc4462.html#section-2.2>`_ says we are not
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required to implement GSS-API error messages. Thus, in many methods within
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this module, if an error occurs an exception will be thrown and the
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connection will be terminated.
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.. seealso:: :doc:`/api/ssh_gss`
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.. versionadded:: 1.15
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"""
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import os
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from hashlib import sha1
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from paramiko.common import DEBUG, max_byte, zero_byte
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from paramiko import util
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from paramiko.message import Message
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from paramiko.py3compat import byte_chr, byte_mask, byte_ord
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from paramiko.ssh_exception import SSHException
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(
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MSG_KEXGSS_INIT,
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MSG_KEXGSS_CONTINUE,
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MSG_KEXGSS_COMPLETE,
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MSG_KEXGSS_HOSTKEY,
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MSG_KEXGSS_ERROR,
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) = range(30, 35)
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(MSG_KEXGSS_GROUPREQ, MSG_KEXGSS_GROUP) = range(40, 42)
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(
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c_MSG_KEXGSS_INIT,
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c_MSG_KEXGSS_CONTINUE,
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c_MSG_KEXGSS_COMPLETE,
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c_MSG_KEXGSS_HOSTKEY,
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c_MSG_KEXGSS_ERROR,
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) = [byte_chr(c) for c in range(30, 35)]
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(c_MSG_KEXGSS_GROUPREQ, c_MSG_KEXGSS_GROUP) = [
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byte_chr(c) for c in range(40, 42)
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]
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class KexGSSGroup1(object):
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"""
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GSS-API / SSPI Authenticated Diffie-Hellman Key Exchange as defined in `RFC
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4462 Section 2 <https://tools.ietf.org/html/rfc4462.html#section-2>`_
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"""
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# draft-ietf-secsh-transport-09.txt, page 17
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P = 0xFFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF # noqa
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G = 2
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b7fffffffffffffff = byte_chr(0x7f) + max_byte * 7 # noqa
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b0000000000000000 = zero_byte * 8 # noqa
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NAME = "gss-group1-sha1-toWM5Slw5Ew8Mqkay+al2g=="
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def __init__(self, transport):
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self.transport = transport
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self.kexgss = self.transport.kexgss_ctxt
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self.gss_host = None
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self.x = 0
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self.e = 0
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self.f = 0
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def start_kex(self):
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"""
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Start the GSS-API / SSPI Authenticated Diffie-Hellman Key Exchange.
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"""
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self._generate_x()
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if self.transport.server_mode:
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# compute f = g^x mod p, but don't send it yet
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self.f = pow(self.G, self.x, self.P)
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self.transport._expect_packet(MSG_KEXGSS_INIT)
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return
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# compute e = g^x mod p (where g=2), and send it
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self.e = pow(self.G, self.x, self.P)
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# Initialize GSS-API Key Exchange
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self.gss_host = self.transport.gss_host
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m = Message()
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m.add_byte(c_MSG_KEXGSS_INIT)
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m.add_string(self.kexgss.ssh_init_sec_context(target=self.gss_host))
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m.add_mpint(self.e)
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self.transport._send_message(m)
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self.transport._expect_packet(
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MSG_KEXGSS_HOSTKEY,
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MSG_KEXGSS_CONTINUE,
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MSG_KEXGSS_COMPLETE,
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MSG_KEXGSS_ERROR,
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)
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def parse_next(self, ptype, m):
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"""
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Parse the next packet.
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:param ptype: The (string) type of the incoming packet
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:param `.Message` m: The paket content
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"""
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if self.transport.server_mode and (ptype == MSG_KEXGSS_INIT):
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return self._parse_kexgss_init(m)
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elif not self.transport.server_mode and (ptype == MSG_KEXGSS_HOSTKEY):
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return self._parse_kexgss_hostkey(m)
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elif self.transport.server_mode and (ptype == MSG_KEXGSS_CONTINUE):
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return self._parse_kexgss_continue(m)
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elif not self.transport.server_mode and (ptype == MSG_KEXGSS_COMPLETE):
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return self._parse_kexgss_complete(m)
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elif ptype == MSG_KEXGSS_ERROR:
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return self._parse_kexgss_error(m)
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msg = "GSS KexGroup1 asked to handle packet type {:d}"
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raise SSHException(msg.format(ptype))
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# ## internals...
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def _generate_x(self):
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"""
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generate an "x" (1 < x < q), where q is (p-1)/2.
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p is a 128-byte (1024-bit) number, where the first 64 bits are 1.
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therefore q can be approximated as a 2^1023. we drop the subset of
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potential x where the first 63 bits are 1, because some of those will
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be larger than q (but this is a tiny tiny subset of potential x).
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"""
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while 1:
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x_bytes = os.urandom(128)
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x_bytes = byte_mask(x_bytes[0], 0x7f) + x_bytes[1:]
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first = x_bytes[:8]
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if first not in (self.b7fffffffffffffff, self.b0000000000000000):
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break
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self.x = util.inflate_long(x_bytes)
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def _parse_kexgss_hostkey(self, m):
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"""
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Parse the SSH2_MSG_KEXGSS_HOSTKEY message (client mode).
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:param `.Message` m: The content of the SSH2_MSG_KEXGSS_HOSTKEY message
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"""
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# client mode
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host_key = m.get_string()
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self.transport.host_key = host_key
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sig = m.get_string()
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self.transport._verify_key(host_key, sig)
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self.transport._expect_packet(MSG_KEXGSS_CONTINUE, MSG_KEXGSS_COMPLETE)
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def _parse_kexgss_continue(self, m):
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"""
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Parse the SSH2_MSG_KEXGSS_CONTINUE message.
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:param `.Message` m: The content of the SSH2_MSG_KEXGSS_CONTINUE
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message
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"""
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if not self.transport.server_mode:
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srv_token = m.get_string()
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m = Message()
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m.add_byte(c_MSG_KEXGSS_CONTINUE)
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m.add_string(
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self.kexgss.ssh_init_sec_context(
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target=self.gss_host, recv_token=srv_token
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)
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)
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self.transport.send_message(m)
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self.transport._expect_packet(
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MSG_KEXGSS_CONTINUE, MSG_KEXGSS_COMPLETE, MSG_KEXGSS_ERROR
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)
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else:
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pass
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def _parse_kexgss_complete(self, m):
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"""
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Parse the SSH2_MSG_KEXGSS_COMPLETE message (client mode).
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:param `.Message` m: The content of the
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SSH2_MSG_KEXGSS_COMPLETE message
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"""
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# client mode
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if self.transport.host_key is None:
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self.transport.host_key = NullHostKey()
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self.f = m.get_mpint()
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if (self.f < 1) or (self.f > self.P - 1):
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raise SSHException('Server kex "f" is out of range')
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mic_token = m.get_string()
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# This must be TRUE, if there is a GSS-API token in this message.
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bool = m.get_boolean()
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srv_token = None
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if bool:
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srv_token = m.get_string()
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K = pow(self.f, self.x, self.P)
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# okay, build up the hash H of
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# (V_C || V_S || I_C || I_S || K_S || e || f || K)
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hm = Message()
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hm.add(
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self.transport.local_version,
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self.transport.remote_version,
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self.transport.local_kex_init,
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self.transport.remote_kex_init,
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)
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hm.add_string(self.transport.host_key.__str__())
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hm.add_mpint(self.e)
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hm.add_mpint(self.f)
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hm.add_mpint(K)
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H = sha1(str(hm)).digest()
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self.transport._set_K_H(K, H)
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if srv_token is not None:
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self.kexgss.ssh_init_sec_context(
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target=self.gss_host, recv_token=srv_token
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)
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self.kexgss.ssh_check_mic(mic_token, H)
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else:
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self.kexgss.ssh_check_mic(mic_token, H)
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self.transport.gss_kex_used = True
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self.transport._activate_outbound()
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def _parse_kexgss_init(self, m):
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"""
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Parse the SSH2_MSG_KEXGSS_INIT message (server mode).
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:param `.Message` m: The content of the SSH2_MSG_KEXGSS_INIT message
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"""
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# server mode
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client_token = m.get_string()
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self.e = m.get_mpint()
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if (self.e < 1) or (self.e > self.P - 1):
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raise SSHException('Client kex "e" is out of range')
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K = pow(self.e, self.x, self.P)
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self.transport.host_key = NullHostKey()
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key = self.transport.host_key.__str__()
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# okay, build up the hash H of
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# (V_C || V_S || I_C || I_S || K_S || e || f || K)
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hm = Message()
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hm.add(
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self.transport.remote_version,
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self.transport.local_version,
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self.transport.remote_kex_init,
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self.transport.local_kex_init,
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)
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hm.add_string(key)
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hm.add_mpint(self.e)
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hm.add_mpint(self.f)
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hm.add_mpint(K)
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H = sha1(hm.asbytes()).digest()
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self.transport._set_K_H(K, H)
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srv_token = self.kexgss.ssh_accept_sec_context(
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self.gss_host, client_token
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)
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m = Message()
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if self.kexgss._gss_srv_ctxt_status:
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mic_token = self.kexgss.ssh_get_mic(
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self.transport.session_id, gss_kex=True
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)
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m.add_byte(c_MSG_KEXGSS_COMPLETE)
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m.add_mpint(self.f)
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m.add_string(mic_token)
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if srv_token is not None:
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m.add_boolean(True)
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m.add_string(srv_token)
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else:
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m.add_boolean(False)
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self.transport._send_message(m)
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self.transport.gss_kex_used = True
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self.transport._activate_outbound()
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else:
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m.add_byte(c_MSG_KEXGSS_CONTINUE)
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m.add_string(srv_token)
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self.transport._send_message(m)
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self.transport._expect_packet(
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MSG_KEXGSS_CONTINUE, MSG_KEXGSS_COMPLETE, MSG_KEXGSS_ERROR
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)
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def _parse_kexgss_error(self, m):
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"""
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Parse the SSH2_MSG_KEXGSS_ERROR message (client mode).
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The server may send a GSS-API error message. if it does, we display
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the error by throwing an exception (client mode).
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:param `.Message` m: The content of the SSH2_MSG_KEXGSS_ERROR message
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:raise SSHException: Contains GSS-API major and minor status as well as
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the error message and the language tag of the
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message
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"""
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maj_status = m.get_int()
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min_status = m.get_int()
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err_msg = m.get_string()
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m.get_string() # we don't care about the language!
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raise SSHException(
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"""GSS-API Error:
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Major Status: {}
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Minor Status: {}
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Error Message: {}
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""".format(
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maj_status, min_status, err_msg
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)
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)
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class KexGSSGroup14(KexGSSGroup1):
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"""
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GSS-API / SSPI Authenticated Diffie-Hellman Group14 Key Exchange as defined
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in `RFC 4462 Section 2
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<https://tools.ietf.org/html/rfc4462.html#section-2>`_
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"""
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P = 0x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noqa
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G = 2
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NAME = "gss-group14-sha1-toWM5Slw5Ew8Mqkay+al2g=="
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class KexGSSGex(object):
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"""
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GSS-API / SSPI Authenticated Diffie-Hellman Group Exchange as defined in
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`RFC 4462 Section 2 <https://tools.ietf.org/html/rfc4462.html#section-2>`_
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"""
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NAME = "gss-gex-sha1-toWM5Slw5Ew8Mqkay+al2g=="
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min_bits = 1024
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max_bits = 8192
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preferred_bits = 2048
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def __init__(self, transport):
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self.transport = transport
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self.kexgss = self.transport.kexgss_ctxt
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self.gss_host = None
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self.p = None
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self.q = None
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self.g = None
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self.x = None
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self.e = None
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self.f = None
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self.old_style = False
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def start_kex(self):
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"""
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Start the GSS-API / SSPI Authenticated Diffie-Hellman Group Exchange
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"""
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if self.transport.server_mode:
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self.transport._expect_packet(MSG_KEXGSS_GROUPREQ)
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return
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# request a bit range: we accept (min_bits) to (max_bits), but prefer
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# (preferred_bits). according to the spec, we shouldn't pull the
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# minimum up above 1024.
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self.gss_host = self.transport.gss_host
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m = Message()
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m.add_byte(c_MSG_KEXGSS_GROUPREQ)
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m.add_int(self.min_bits)
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m.add_int(self.preferred_bits)
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m.add_int(self.max_bits)
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self.transport._send_message(m)
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self.transport._expect_packet(MSG_KEXGSS_GROUP)
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def parse_next(self, ptype, m):
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"""
|
||
|
Parse the next packet.
|
||
|
|
||
|
:param ptype: The (string) type of the incoming packet
|
||
|
:param `.Message` m: The paket content
|
||
|
"""
|
||
|
if ptype == MSG_KEXGSS_GROUPREQ:
|
||
|
return self._parse_kexgss_groupreq(m)
|
||
|
elif ptype == MSG_KEXGSS_GROUP:
|
||
|
return self._parse_kexgss_group(m)
|
||
|
elif ptype == MSG_KEXGSS_INIT:
|
||
|
return self._parse_kexgss_gex_init(m)
|
||
|
elif ptype == MSG_KEXGSS_HOSTKEY:
|
||
|
return self._parse_kexgss_hostkey(m)
|
||
|
elif ptype == MSG_KEXGSS_CONTINUE:
|
||
|
return self._parse_kexgss_continue(m)
|
||
|
elif ptype == MSG_KEXGSS_COMPLETE:
|
||
|
return self._parse_kexgss_complete(m)
|
||
|
elif ptype == MSG_KEXGSS_ERROR:
|
||
|
return self._parse_kexgss_error(m)
|
||
|
msg = "KexGex asked to handle packet type {:d}"
|
||
|
raise SSHException(msg.format(ptype))
|
||
|
|
||
|
# ## internals...
|
||
|
|
||
|
def _generate_x(self):
|
||
|
# generate an "x" (1 < x < (p-1)/2).
|
||
|
q = (self.p - 1) // 2
|
||
|
qnorm = util.deflate_long(q, 0)
|
||
|
qhbyte = byte_ord(qnorm[0])
|
||
|
byte_count = len(qnorm)
|
||
|
qmask = 0xff
|
||
|
while not (qhbyte & 0x80):
|
||
|
qhbyte <<= 1
|
||
|
qmask >>= 1
|
||
|
while True:
|
||
|
x_bytes = os.urandom(byte_count)
|
||
|
x_bytes = byte_mask(x_bytes[0], qmask) + x_bytes[1:]
|
||
|
x = util.inflate_long(x_bytes, 1)
|
||
|
if (x > 1) and (x < q):
|
||
|
break
|
||
|
self.x = x
|
||
|
|
||
|
def _parse_kexgss_groupreq(self, m):
|
||
|
"""
|
||
|
Parse the SSH2_MSG_KEXGSS_GROUPREQ message (server mode).
|
||
|
|
||
|
:param `.Message` m: The content of the
|
||
|
SSH2_MSG_KEXGSS_GROUPREQ message
|
||
|
"""
|
||
|
minbits = m.get_int()
|
||
|
preferredbits = m.get_int()
|
||
|
maxbits = m.get_int()
|
||
|
# smoosh the user's preferred size into our own limits
|
||
|
if preferredbits > self.max_bits:
|
||
|
preferredbits = self.max_bits
|
||
|
if preferredbits < self.min_bits:
|
||
|
preferredbits = self.min_bits
|
||
|
# fix min/max if they're inconsistent. technically, we could just pout
|
||
|
# and hang up, but there's no harm in giving them the benefit of the
|
||
|
# doubt and just picking a bitsize for them.
|
||
|
if minbits > preferredbits:
|
||
|
minbits = preferredbits
|
||
|
if maxbits < preferredbits:
|
||
|
maxbits = preferredbits
|
||
|
# now save a copy
|
||
|
self.min_bits = minbits
|
||
|
self.preferred_bits = preferredbits
|
||
|
self.max_bits = maxbits
|
||
|
# generate prime
|
||
|
pack = self.transport._get_modulus_pack()
|
||
|
if pack is None:
|
||
|
raise SSHException("Can't do server-side gex with no modulus pack")
|
||
|
self.transport._log(
|
||
|
DEBUG, # noqa
|
||
|
"Picking p ({} <= {} <= {} bits)".format(
|
||
|
minbits, preferredbits, maxbits
|
||
|
),
|
||
|
)
|
||
|
self.g, self.p = pack.get_modulus(minbits, preferredbits, maxbits)
|
||
|
m = Message()
|
||
|
m.add_byte(c_MSG_KEXGSS_GROUP)
|
||
|
m.add_mpint(self.p)
|
||
|
m.add_mpint(self.g)
|
||
|
self.transport._send_message(m)
|
||
|
self.transport._expect_packet(MSG_KEXGSS_INIT)
|
||
|
|
||
|
def _parse_kexgss_group(self, m):
|
||
|
"""
|
||
|
Parse the SSH2_MSG_KEXGSS_GROUP message (client mode).
|
||
|
|
||
|
:param `Message` m: The content of the SSH2_MSG_KEXGSS_GROUP message
|
||
|
"""
|
||
|
self.p = m.get_mpint()
|
||
|
self.g = m.get_mpint()
|
||
|
# reject if p's bit length < 1024 or > 8192
|
||
|
bitlen = util.bit_length(self.p)
|
||
|
if (bitlen < 1024) or (bitlen > 8192):
|
||
|
raise SSHException(
|
||
|
"Server-generated gex p (don't ask) is out of range "
|
||
|
"({} bits)".format(bitlen)
|
||
|
)
|
||
|
self.transport._log(
|
||
|
DEBUG, "Got server p ({} bits)".format(bitlen)
|
||
|
) # noqa
|
||
|
self._generate_x()
|
||
|
# now compute e = g^x mod p
|
||
|
self.e = pow(self.g, self.x, self.p)
|
||
|
m = Message()
|
||
|
m.add_byte(c_MSG_KEXGSS_INIT)
|
||
|
m.add_string(self.kexgss.ssh_init_sec_context(target=self.gss_host))
|
||
|
m.add_mpint(self.e)
|
||
|
self.transport._send_message(m)
|
||
|
self.transport._expect_packet(
|
||
|
MSG_KEXGSS_HOSTKEY,
|
||
|
MSG_KEXGSS_CONTINUE,
|
||
|
MSG_KEXGSS_COMPLETE,
|
||
|
MSG_KEXGSS_ERROR,
|
||
|
)
|
||
|
|
||
|
def _parse_kexgss_gex_init(self, m):
|
||
|
"""
|
||
|
Parse the SSH2_MSG_KEXGSS_INIT message (server mode).
|
||
|
|
||
|
:param `Message` m: The content of the SSH2_MSG_KEXGSS_INIT message
|
||
|
"""
|
||
|
client_token = m.get_string()
|
||
|
self.e = m.get_mpint()
|
||
|
if (self.e < 1) or (self.e > self.p - 1):
|
||
|
raise SSHException('Client kex "e" is out of range')
|
||
|
self._generate_x()
|
||
|
self.f = pow(self.g, self.x, self.p)
|
||
|
K = pow(self.e, self.x, self.p)
|
||
|
self.transport.host_key = NullHostKey()
|
||
|
key = self.transport.host_key.__str__()
|
||
|
# okay, build up the hash H of
|
||
|
# (V_C || V_S || I_C || I_S || K_S || min || n || max || p || g || e || f || K) # noqa
|
||
|
hm = Message()
|
||
|
hm.add(
|
||
|
self.transport.remote_version,
|
||
|
self.transport.local_version,
|
||
|
self.transport.remote_kex_init,
|
||
|
self.transport.local_kex_init,
|
||
|
key,
|
||
|
)
|
||
|
hm.add_int(self.min_bits)
|
||
|
hm.add_int(self.preferred_bits)
|
||
|
hm.add_int(self.max_bits)
|
||
|
hm.add_mpint(self.p)
|
||
|
hm.add_mpint(self.g)
|
||
|
hm.add_mpint(self.e)
|
||
|
hm.add_mpint(self.f)
|
||
|
hm.add_mpint(K)
|
||
|
H = sha1(hm.asbytes()).digest()
|
||
|
self.transport._set_K_H(K, H)
|
||
|
srv_token = self.kexgss.ssh_accept_sec_context(
|
||
|
self.gss_host, client_token
|
||
|
)
|
||
|
m = Message()
|
||
|
if self.kexgss._gss_srv_ctxt_status:
|
||
|
mic_token = self.kexgss.ssh_get_mic(
|
||
|
self.transport.session_id, gss_kex=True
|
||
|
)
|
||
|
m.add_byte(c_MSG_KEXGSS_COMPLETE)
|
||
|
m.add_mpint(self.f)
|
||
|
m.add_string(mic_token)
|
||
|
if srv_token is not None:
|
||
|
m.add_boolean(True)
|
||
|
m.add_string(srv_token)
|
||
|
else:
|
||
|
m.add_boolean(False)
|
||
|
self.transport._send_message(m)
|
||
|
self.transport.gss_kex_used = True
|
||
|
self.transport._activate_outbound()
|
||
|
else:
|
||
|
m.add_byte(c_MSG_KEXGSS_CONTINUE)
|
||
|
m.add_string(srv_token)
|
||
|
self.transport._send_message(m)
|
||
|
self.transport._expect_packet(
|
||
|
MSG_KEXGSS_CONTINUE, MSG_KEXGSS_COMPLETE, MSG_KEXGSS_ERROR
|
||
|
)
|
||
|
|
||
|
def _parse_kexgss_hostkey(self, m):
|
||
|
"""
|
||
|
Parse the SSH2_MSG_KEXGSS_HOSTKEY message (client mode).
|
||
|
|
||
|
:param `Message` m: The content of the SSH2_MSG_KEXGSS_HOSTKEY message
|
||
|
"""
|
||
|
# client mode
|
||
|
host_key = m.get_string()
|
||
|
self.transport.host_key = host_key
|
||
|
sig = m.get_string()
|
||
|
self.transport._verify_key(host_key, sig)
|
||
|
self.transport._expect_packet(MSG_KEXGSS_CONTINUE, MSG_KEXGSS_COMPLETE)
|
||
|
|
||
|
def _parse_kexgss_continue(self, m):
|
||
|
"""
|
||
|
Parse the SSH2_MSG_KEXGSS_CONTINUE message.
|
||
|
|
||
|
:param `Message` m: The content of the SSH2_MSG_KEXGSS_CONTINUE message
|
||
|
"""
|
||
|
if not self.transport.server_mode:
|
||
|
srv_token = m.get_string()
|
||
|
m = Message()
|
||
|
m.add_byte(c_MSG_KEXGSS_CONTINUE)
|
||
|
m.add_string(
|
||
|
self.kexgss.ssh_init_sec_context(
|
||
|
target=self.gss_host, recv_token=srv_token
|
||
|
)
|
||
|
)
|
||
|
self.transport.send_message(m)
|
||
|
self.transport._expect_packet(
|
||
|
MSG_KEXGSS_CONTINUE, MSG_KEXGSS_COMPLETE, MSG_KEXGSS_ERROR
|
||
|
)
|
||
|
else:
|
||
|
pass
|
||
|
|
||
|
def _parse_kexgss_complete(self, m):
|
||
|
"""
|
||
|
Parse the SSH2_MSG_KEXGSS_COMPLETE message (client mode).
|
||
|
|
||
|
:param `Message` m: The content of the SSH2_MSG_KEXGSS_COMPLETE message
|
||
|
"""
|
||
|
if self.transport.host_key is None:
|
||
|
self.transport.host_key = NullHostKey()
|
||
|
self.f = m.get_mpint()
|
||
|
mic_token = m.get_string()
|
||
|
# This must be TRUE, if there is a GSS-API token in this message.
|
||
|
bool = m.get_boolean()
|
||
|
srv_token = None
|
||
|
if bool:
|
||
|
srv_token = m.get_string()
|
||
|
if (self.f < 1) or (self.f > self.p - 1):
|
||
|
raise SSHException('Server kex "f" is out of range')
|
||
|
K = pow(self.f, self.x, self.p)
|
||
|
# okay, build up the hash H of
|
||
|
# (V_C || V_S || I_C || I_S || K_S || min || n || max || p || g || e || f || K) # noqa
|
||
|
hm = Message()
|
||
|
hm.add(
|
||
|
self.transport.local_version,
|
||
|
self.transport.remote_version,
|
||
|
self.transport.local_kex_init,
|
||
|
self.transport.remote_kex_init,
|
||
|
self.transport.host_key.__str__(),
|
||
|
)
|
||
|
if not self.old_style:
|
||
|
hm.add_int(self.min_bits)
|
||
|
hm.add_int(self.preferred_bits)
|
||
|
if not self.old_style:
|
||
|
hm.add_int(self.max_bits)
|
||
|
hm.add_mpint(self.p)
|
||
|
hm.add_mpint(self.g)
|
||
|
hm.add_mpint(self.e)
|
||
|
hm.add_mpint(self.f)
|
||
|
hm.add_mpint(K)
|
||
|
H = sha1(hm.asbytes()).digest()
|
||
|
self.transport._set_K_H(K, H)
|
||
|
if srv_token is not None:
|
||
|
self.kexgss.ssh_init_sec_context(
|
||
|
target=self.gss_host, recv_token=srv_token
|
||
|
)
|
||
|
self.kexgss.ssh_check_mic(mic_token, H)
|
||
|
else:
|
||
|
self.kexgss.ssh_check_mic(mic_token, H)
|
||
|
self.transport.gss_kex_used = True
|
||
|
self.transport._activate_outbound()
|
||
|
|
||
|
def _parse_kexgss_error(self, m):
|
||
|
"""
|
||
|
Parse the SSH2_MSG_KEXGSS_ERROR message (client mode).
|
||
|
The server may send a GSS-API error message. if it does, we display
|
||
|
the error by throwing an exception (client mode).
|
||
|
|
||
|
:param `Message` m: The content of the SSH2_MSG_KEXGSS_ERROR message
|
||
|
:raise SSHException: Contains GSS-API major and minor status as well as
|
||
|
the error message and the language tag of the
|
||
|
message
|
||
|
"""
|
||
|
maj_status = m.get_int()
|
||
|
min_status = m.get_int()
|
||
|
err_msg = m.get_string()
|
||
|
m.get_string() # we don't care about the language (lang_tag)!
|
||
|
raise SSHException(
|
||
|
"""GSS-API Error:
|
||
|
Major Status: {}
|
||
|
Minor Status: {}
|
||
|
Error Message: {}
|
||
|
""".format(
|
||
|
maj_status, min_status, err_msg
|
||
|
)
|
||
|
)
|
||
|
|
||
|
|
||
|
class NullHostKey(object):
|
||
|
"""
|
||
|
This class represents the Null Host Key for GSS-API Key Exchange as defined
|
||
|
in `RFC 4462 Section 5
|
||
|
<https://tools.ietf.org/html/rfc4462.html#section-5>`_
|
||
|
"""
|
||
|
|
||
|
def __init__(self):
|
||
|
self.key = ""
|
||
|
|
||
|
def __str__(self):
|
||
|
return self.key
|
||
|
|
||
|
def get_name(self):
|
||
|
return self.key
|