Imported Upstream version 1.5.2upstream/1.5.2

1 files changed, 136 insertions, 0 deletions

diff --git a/paramiko/kex_group1.py b/paramiko/kex_group1.py
new file mode 100644
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+++ b/paramiko/kex_group1.py
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+# Copyright (C) 2003-2005 Robey Pointer <robey@lag.net>
+#
+# 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 distrubuted 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.
+"""
+
+from Crypto.Hash import SHA
+
+from paramiko.common import *
+from paramiko import util
+from paramiko.message import Message
+from paramiko.ssh_exception import SSHException
+
+
+_MSG_KEXDH_INIT, _MSG_KEXDH_REPLY = range(30, 32)
+
+# draft-ietf-secsh-transport-09.txt, page 17
+P = 0xFFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFFL
+G = 2
+
+
+class KexGroup1(object):
+
+    name = 'diffie-hellman-group1-sha1'
+
+    def __init__(self, transport):
+        self.transport = transport
+        self.x = 0L
+        self.e = 0L
+        self.f = 0L
+
+    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(G, self.x, P)
+            self.transport._expect_packet(_MSG_KEXDH_INIT)
+            return
+        # compute e = g^x mod p (where g=2), and send it
+        self.e = pow(G, self.x, P)
+        m = Message()
+        m.add_byte(chr(_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:
+            self.transport.randpool.stir()
+            x_bytes = self.transport.randpool.get_bytes(128)
+            x_bytes = chr(ord(x_bytes[0]) & 0x7f) + x_bytes[1:]
+            if (x_bytes[:8] != '\x7F\xFF\xFF\xFF\xFF\xFF\xFF\xFF') and \
+                   (x_bytes[:8] != '\x00\x00\x00\x00\x00\x00\x00\x00'):
+                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 > P - 1):
+            raise SSHException('Server kex "f" is out of range')
+        sig = m.get_string()
+        K = pow(self.f, self.x, 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, SHA.new(str(hm)).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 > P - 1):
+            raise SSHException('Client kex "e" is out of range')
+        K = pow(self.e, self.x, P)
+        key = str(self.transport.get_server_key())
+        # 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 = SHA.new(str(hm)).digest()
+        self.transport._set_K_H(K, H)
+        # sign it
+        sig = self.transport.get_server_key().sign_ssh_data(self.transport.randpool, H)
+        # send reply
+        m = Message()
+        m.add_byte(chr(_MSG_KEXDH_REPLY))
+        m.add_string(key)
+        m.add_mpint(self.f)
+        m.add_string(str(sig))
+        self.transport._send_message(m)
+        self.transport._activate_outbound()