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| def _parse_kex_init(self, m):
cookie = m.get_bytes(16)
kex_algo_list = m.get_list()
server_key_algo_list = m.get_list()
client_encrypt_algo_list = m.get_list()
server_encrypt_algo_list = m.get_list()
client_mac_algo_list = m.get_list()
server_mac_algo_list = m.get_list()
client_compress_algo_list = m.get_list()
server_compress_algo_list = m.get_list()
client_lang_list = m.get_list()
server_lang_list = m.get_list()
kex_follows = m.get_boolean()
unused = m.get_int()
self._log(DEBUG, 'kex algos:' + str(kex_algo_list) + ' server key:' + str(server_key_algo_list) + \
' client encrypt:' + str(client_encrypt_algo_list) + \
' server encrypt:' + str(server_encrypt_algo_list) + \
' client mac:' + str(client_mac_algo_list) + \
' server mac:' + str(server_mac_algo_list) + \
' client compress:' + str(client_compress_algo_list) + \
' server compress:' + str(server_compress_algo_list) + \
' client lang:' + str(client_lang_list) + \
' server lang:' + str(server_lang_list) + \
' kex follows?' + str(kex_follows))
# as a server, we pick the first item in the client's list that we support.
# as a client, we pick the first item in our list that the server supports.
if self.server_mode:
agreed_kex = filter(self._preferred_kex.__contains__, kex_algo_list)
else:
agreed_kex = filter(kex_algo_list.__contains__, self._preferred_kex)
if len(agreed_kex) == 0:
raise SSHException('Incompatible ssh peer (no acceptable kex algorithm)')
self.kex_engine = self._kex_info[agreed_kex[0]](self)
if self.server_mode:
available_server_keys = filter(self.server_key_dict.keys().__contains__,
self._preferred_keys)
agreed_keys = filter(available_server_keys.__contains__, server_key_algo_list)
else:
agreed_keys = filter(server_key_algo_list.__contains__, self._preferred_keys)
if len(agreed_keys) == 0:
raise SSHException('Incompatible ssh peer (no acceptable host key)')
self.host_key_type = agreed_keys[0]
if self.server_mode and (self.get_server_key() is None):
raise SSHException('Incompatible ssh peer (can\'t match requested host key type)')
if self.server_mode:
agreed_local_ciphers = filter(self._preferred_ciphers.__contains__,
server_encrypt_algo_list)
agreed_remote_ciphers = filter(self._preferred_ciphers.__contains__,
client_encrypt_algo_list)
else:
agreed_local_ciphers = filter(client_encrypt_algo_list.__contains__,
self._preferred_ciphers)
agreed_remote_ciphers = filter(server_encrypt_algo_list.__contains__,
self._preferred_ciphers)
if (len(agreed_local_ciphers) == 0) or (len(agreed_remote_ciphers) == 0):
raise SSHException('Incompatible ssh server (no acceptable ciphers)')
self.local_cipher = agreed_local_ciphers[0]
self.remote_cipher = agreed_remote_ciphers[0]
self._log(DEBUG, 'Ciphers agreed: local=%s, remote=%s' % (self.local_cipher, self.remote_cipher))
if self.server_mode:
agreed_remote_macs = filter(self._preferred_macs.__contains__, client_mac_algo_list)
agreed_local_macs = filter(self._preferred_macs.__contains__, server_mac_algo_list)
else:
agreed_local_macs = filter(client_mac_algo_list.__contains__, self._preferred_macs)
agreed_remote_macs = filter(server_mac_algo_list.__contains__, self._preferred_macs)
if (len(agreed_local_macs) == 0) or (len(agreed_remote_macs) == 0):
raise SSHException('Incompatible ssh server (no acceptable macs)')
self.local_mac = agreed_local_macs[0]
self.remote_mac = agreed_remote_macs[0]
if self.server_mode:
agreed_remote_compression = filter(self._preferred_compression.__contains__, client_compress_algo_list)
agreed_local_compression = filter(self._preferred_compression.__contains__, server_compress_algo_list)
else:
agreed_local_compression = filter(client_compress_algo_list.__contains__, self._preferred_compression)
agreed_remote_compression = filter(server_compress_algo_list.__contains__, self._preferred_compression)
if (len(agreed_local_compression) == 0) or (len(agreed_remote_compression) == 0):
raise SSHException('Incompatible ssh server (no acceptable compression) %r %r %r' % (agreed_local_compression, agreed_remote_compression, self._preferred_compression))
self.local_compression = agreed_local_compression[0]
self.remote_compression = agreed_remote_compression[0]
self._log(DEBUG, 'using kex %s; server key type %s; cipher: local %s, remote %s; mac: local %s, remote %s; compression: local %s, remote %s' %
(agreed_kex[0], self.host_key_type, self.local_cipher, self.remote_cipher, self.local_mac,
self.remote_mac, self.local_compression, self.remote_compression))
# save for computing hash later...
# now wait! openssh has a bug (and others might too) where there are
# actually some extra bytes (one NUL byte in openssh's case) added to
# the end of the packet but not parsed. turns out we need to throw
# away those bytes because they aren't part of the hash.
self.remote_kex_init = chr(MSG_KEXINIT) + m.get_so_far() |
