示例#1
0
 def _parse_kexdh_gex_init(self, m):
     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)
     key = bytes(self.transport.get_server_key())
     # 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)
     hm = Message()
     hm.add(self.transport.remote_version, self.transport.local_version,
            self.transport.remote_kex_init, self.transport.local_kex_init,
            key)
     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 = SHA.new(bytes(hm)).digest()
     self.transport._set_K_H(K, H)
     # sign it
     sig = self.transport.get_server_key().sign_ssh_data(self.transport.rng, H)
     # send reply
     m = Message()
     m.add_byte(pack_byte(_MSG_KEXDH_GEX_REPLY))
     m.add_string(key)
     m.add_mpint(self.f)
     m.add_string(bytes(sig))
     self.transport._send_message(m)
     self.transport._activate_outbound()
示例#2
0
 def _parse_kexdh_gex_request(self, m):
     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, 'Picking p (%d <= %d <= %d bits)' % (minbits, preferredbits, maxbits))
     self.g, self.p = pack.get_modulus(minbits, preferredbits, maxbits)
     m = Message()
     m.add_byte(pack_byte(_MSG_KEXDH_GEX_GROUP))
     m.add_mpint(self.p)
     m.add_mpint(self.g)
     self.transport._send_message(m)
     self.transport._expect_packet(_MSG_KEXDH_GEX_INIT)