/usr/lib/python3/dist-packages/paramiko/kex_group1.py is in python3-paramiko 2.0.0-1ubuntu1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 | # Copyright (C) 2003-2007 Robey Pointer <robeypointer@gmail.com>
#
# This file is part of paramiko.
#
# Paramiko is free software; you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option)
# any later version.
#
# Paramiko is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
"""
Standard SSH key exchange ("kex" if you wanna sound cool). Diffie-Hellman of
1024 bit key halves, using a known "p" prime and "g" generator.
"""
import os
from hashlib import sha1
from paramiko import util
from paramiko.common import max_byte, zero_byte
from paramiko.message import Message
from paramiko.py3compat import byte_chr, long, byte_mask
from paramiko.ssh_exception import SSHException
_MSG_KEXDH_INIT, _MSG_KEXDH_REPLY = range(30, 32)
c_MSG_KEXDH_INIT, c_MSG_KEXDH_REPLY = [byte_chr(c) for c in range(30, 32)]
b7fffffffffffffff = byte_chr(0x7f) + max_byte * 7
b0000000000000000 = zero_byte * 8
class KexGroup1(object):
# draft-ietf-secsh-transport-09.txt, page 17
P = 0xFFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF
G = 2
name = 'diffie-hellman-group1-sha1'
hash_algo = sha1
def __init__(self, transport):
self.transport = transport
self.x = long(0)
self.e = long(0)
self.f = long(0)
def start_kex(self):
self._generate_x()
if self.transport.server_mode:
# compute f = g^x mod p, but don't send it yet
self.f = pow(self.G, self.x, self.P)
self.transport._expect_packet(_MSG_KEXDH_INIT)
return
# compute e = g^x mod p (where g=2), and send it
self.e = pow(self.G, self.x, self.P)
m = Message()
m.add_byte(c_MSG_KEXDH_INIT)
m.add_mpint(self.e)
self.transport._send_message(m)
self.transport._expect_packet(_MSG_KEXDH_REPLY)
def parse_next(self, ptype, m):
if self.transport.server_mode and (ptype == _MSG_KEXDH_INIT):
return self._parse_kexdh_init(m)
elif not self.transport.server_mode and (ptype == _MSG_KEXDH_REPLY):
return self._parse_kexdh_reply(m)
raise SSHException('KexGroup1 asked to handle packet type %d' % ptype)
### internals...
def _generate_x(self):
# generate an "x" (1 < x < q), where q is (p-1)/2.
# p is a 128-byte (1024-bit) number, where the first 64 bits are 1.
# therefore q can be approximated as a 2^1023. we drop the subset of
# potential x where the first 63 bits are 1, because some of those will be
# larger than q (but this is a tiny tiny subset of potential x).
while 1:
x_bytes = os.urandom(128)
x_bytes = byte_mask(x_bytes[0], 0x7f) + x_bytes[1:]
if (x_bytes[:8] != b7fffffffffffffff and
x_bytes[:8] != b0000000000000000):
break
self.x = util.inflate_long(x_bytes)
def _parse_kexdh_reply(self, m):
# client mode
host_key = m.get_string()
self.f = m.get_mpint()
if (self.f < 1) or (self.f > self.P - 1):
raise SSHException('Server kex "f" is out of range')
sig = m.get_binary()
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 || e || f || K)
hm = Message()
hm.add(self.transport.local_version, self.transport.remote_version,
self.transport.local_kex_init, self.transport.remote_kex_init)
hm.add_string(host_key)
hm.add_mpint(self.e)
hm.add_mpint(self.f)
hm.add_mpint(K)
self.transport._set_K_H(K, sha1(hm.asbytes()).digest())
self.transport._verify_key(host_key, sig)
self.transport._activate_outbound()
def _parse_kexdh_init(self, m):
# server mode
self.e = m.get_mpint()
if (self.e < 1) or (self.e > self.P - 1):
raise SSHException('Client kex "e" is out of range')
K = pow(self.e, self.x, self.P)
key = self.transport.get_server_key().asbytes()
# okay, build up the hash H of (V_C || V_S || I_C || I_S || K_S || e || f || K)
hm = Message()
hm.add(self.transport.remote_version, self.transport.local_version,
self.transport.remote_kex_init, self.transport.local_kex_init)
hm.add_string(key)
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)
# sign it
sig = self.transport.get_server_key().sign_ssh_data(H)
# send reply
m = Message()
m.add_byte(c_MSG_KEXDH_REPLY)
m.add_string(key)
m.add_mpint(self.f)
m.add_string(sig)
self.transport._send_message(m)
self.transport._activate_outbound()
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