/usr/lib/python3/dist-packages/asyncssh/dh.py is in python3-asyncssh 1.11.1-1.
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# All rights reserved.
#
# This program and the accompanying materials are made available under
# the terms of the Eclipse Public License v1.0 which accompanies this
# distribution and is available at:
#
# http://www.eclipse.org/legal/epl-v10.html
#
# Contributors:
# Ron Frederick - initial implementation, API, and documentation
"""SSH Diffie-Hellman key exchange handlers"""
from hashlib import sha1, sha256, sha512
from .constants import DEFAULT_LANG
from .constants import DISC_KEY_EXCHANGE_FAILED, DISC_PROTOCOL_ERROR
from .gss import GSSError
from .kex import Kex, register_kex_alg, register_gss_kex_alg
from .logging import logger
from .misc import DisconnectError, randrange
from .packet import Boolean, Byte, MPInt, String, UInt32
# pylint: disable=bad-whitespace,line-too-long
# SSH KEX DH message values
MSG_KEXDH_INIT = 30
MSG_KEXDH_REPLY = 31
# SSH KEX DH group exchange message values
MSG_KEX_DH_GEX_REQUEST_OLD = 30
MSG_KEX_DH_GEX_GROUP = 31
MSG_KEX_DH_GEX_INIT = 32
MSG_KEX_DH_GEX_REPLY = 33
MSG_KEX_DH_GEX_REQUEST = 34
# SSH KEXGSS message value
MSG_KEXGSS_INIT = 30
MSG_KEXGSS_CONTINUE = 31
MSG_KEXGSS_COMPLETE = 32
MSG_KEXGSS_HOSTKEY = 33
MSG_KEXGSS_ERROR = 34
MSG_KEXGSS_GROUPREQ = 40
MSG_KEXGSS_GROUP = 41
# SSH KEX group exchange key sizes
KEX_DH_GEX_MIN_SIZE = 1024
KEX_DH_GEX_PREFERRED_SIZE = 2048
KEX_DH_GEX_MAX_SIZE = 8192
# SSH Diffie-Hellman group 1 parameters
_group1_g = 2
_group1_p = 0xffffffffffffffffc90fdaa22168c234c4c6628b80dc1cd129024e088a67cc74020bbea63b139b22514a08798e3404ddef9519b3cd3a431b302b0a6df25f14374fe1356d6d51c245e485b576625e7ec6f44c42e9a637ed6b0bff5cb6f406b7edee386bfb5a899fa5ae9f24117c4b1fe649286651ece65381ffffffffffffffff
# SSH Diffie-Hellman group 14 parameters
_group14_g = 2
_group14_p = 0xffffffffffffffffc90fdaa22168c234c4c6628b80dc1cd129024e088a67cc74020bbea63b139b22514a08798e3404ddef9519b3cd3a431b302b0a6df25f14374fe1356d6d51c245e485b576625e7ec6f44c42e9a637ed6b0bff5cb6f406b7edee386bfb5a899fa5ae9f24117c4b1fe649286651ece45b3dc2007cb8a163bf0598da48361c55d39a69163fa8fd24cf5f83655d23dca3ad961c62f356208552bb9ed529077096966d670c354e4abc9804f1746c08ca18217c32905e462e36ce3be39e772c180e86039b2783a2ec07a28fb5c55df06f4c52c9de2bcbf6955817183995497cea956ae515d2261898fa051015728e5a8aacaa68ffffffffffffffff
# SSH Diffie-Hellman group 15 parameters
_group15_g = 2
_group15_p = 0xffffffffffffffffc90fdaa22168c234c4c6628b80dc1cd129024e088a67cc74020bbea63b139b22514a08798e3404ddef9519b3cd3a431b302b0a6df25f14374fe1356d6d51c245e485b576625e7ec6f44c42e9a637ed6b0bff5cb6f406b7edee386bfb5a899fa5ae9f24117c4b1fe649286651ece45b3dc2007cb8a163bf0598da48361c55d39a69163fa8fd24cf5f83655d23dca3ad961c62f356208552bb9ed529077096966d670c354e4abc9804f1746c08ca18217c32905e462e36ce3be39e772c180e86039b2783a2ec07a28fb5c55df06f4c52c9de2bcbf6955817183995497cea956ae515d2261898fa051015728e5a8aaac42dad33170d04507a33a85521abdf1cba64ecfb850458dbef0a8aea71575d060c7db3970f85a6e1e4c7abf5ae8cdb0933d71e8c94e04a25619dcee3d2261ad2ee6bf12ffa06d98a0864d87602733ec86a64521f2b18177b200cbbe117577a615d6c770988c0bad946e208e24fa074e5ab3143db5bfce0fd108e4b82d120a93ad2caffffffffffffffff
# SSH Diffie-Hellman group 16 parameters
_group16_g = 2
_group16_p = 0xffffffffffffffffc90fdaa22168c234c4c6628b80dc1cd129024e088a67cc74020bbea63b139b22514a08798e3404ddef9519b3cd3a431b302b0a6df25f14374fe1356d6d51c245e485b576625e7ec6f44c42e9a637ed6b0bff5cb6f406b7edee386bfb5a899fa5ae9f24117c4b1fe649286651ece45b3dc2007cb8a163bf0598da48361c55d39a69163fa8fd24cf5f83655d23dca3ad961c62f356208552bb9ed529077096966d670c354e4abc9804f1746c08ca18217c32905e462e36ce3be39e772c180e86039b2783a2ec07a28fb5c55df06f4c52c9de2bcbf6955817183995497cea956ae515d2261898fa051015728e5a8aaac42dad33170d04507a33a85521abdf1cba64ecfb850458dbef0a8aea71575d060c7db3970f85a6e1e4c7abf5ae8cdb0933d71e8c94e04a25619dcee3d2261ad2ee6bf12ffa06d98a0864d87602733ec86a64521f2b18177b200cbbe117577a615d6c770988c0bad946e208e24fa074e5ab3143db5bfce0fd108e4b82d120a92108011a723c12a787e6d788719a10bdba5b2699c327186af4e23c1a946834b6150bda2583e9ca2ad44ce8dbbbc2db04de8ef92e8efc141fbecaa6287c59474e6bc05d99b2964fa090c3a2233ba186515be7ed1f612970cee2d7afb81bdd762170481cd0069127d5b05aa993b4ea988d8fddc186ffb7dc90a6c08f4df435c934063199ffffffffffffffff
# SSH Diffie-Hellman group 17 parameters
_group17_g = 2
_group17_p = 0xffffffffffffffffc90fdaa22168c234c4c6628b80dc1cd129024e088a67cc74020bbea63b139b22514a08798e3404ddef9519b3cd3a431b302b0a6df25f14374fe1356d6d51c245e485b576625e7ec6f44c42e9a637ed6b0bff5cb6f406b7edee386bfb5a899fa5ae9f24117c4b1fe649286651ece45b3dc2007cb8a163bf0598da48361c55d39a69163fa8fd24cf5f83655d23dca3ad961c62f356208552bb9ed529077096966d670c354e4abc9804f1746c08ca18217c32905e462e36ce3be39e772c180e86039b2783a2ec07a28fb5c55df06f4c52c9de2bcbf6955817183995497cea956ae515d2261898fa051015728e5a8aaac42dad33170d04507a33a85521abdf1cba64ecfb850458dbef0a8aea71575d060c7db3970f85a6e1e4c7abf5ae8cdb0933d71e8c94e04a25619dcee3d2261ad2ee6bf12ffa06d98a0864d87602733ec86a64521f2b18177b200cbbe117577a615d6c770988c0bad946e208e24fa074e5ab3143db5bfce0fd108e4b82d120a92108011a723c12a787e6d788719a10bdba5b2699c327186af4e23c1a946834b6150bda2583e9ca2ad44ce8dbbbc2db04de8ef92e8efc141fbecaa6287c59474e6bc05d99b2964fa090c3a2233ba186515be7ed1f612970cee2d7afb81bdd762170481cd0069127d5b05aa993b4ea988d8fddc186ffb7dc90a6c08f4df435c93402849236c3fab4d27c7026c1d4dcb2602646dec9751e763dba37bdf8ff9406ad9e530ee5db382f413001aeb06a53ed9027d831179727b0865a8918da3edbebcf9b14ed44ce6cbaced4bb1bdb7f1447e6cc254b332051512bd7af426fb8f401378cd2bf5983ca01c64b92ecf032ea15d1721d03f482d7ce6e74fef6d55e702f46980c82b5a84031900b1c9e59e7c97fbec7e8f323a97a7e36cc88be0f1d45b7ff585ac54bd407b22b4154aacc8f6d7ebf48e1d814cc5ed20f8037e0a79715eef29be32806a1d58bb7c5da76f550aa3d8a1fbff0eb19ccb1a313d55cda56c9ec2ef29632387fe8d76e3c0468043e8f663f4860ee12bf2d5b0b7474d6e694f91e6dcc4024ffffffffffffffff
# SSH Diffie-Hellman group 18 parameters
_group18_g = 2
_group18_p = 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
_dh_gex_groups = ((1024, _group1_g, _group1_p),
(2048, _group14_g, _group14_p),
(3072, _group15_g, _group15_p),
(4096, _group16_g, _group16_p),
(6144, _group17_g, _group17_p),
(8192, _group18_g, _group18_p))
# pylint: enable=bad-whitespace,line-too-long
# Short variable names are used here, matching names in the spec
# pylint: disable=invalid-name
class _KexDHBase(Kex):
"""Abstract base class for Diffie-Hellman key exchange"""
_init_type = None
_reply_type = None
def __init__(self, alg, conn, hash_alg):
super().__init__(alg, conn, hash_alg)
self._g = None
self._p = None
self._q = None
self._x = None
self._e = None
self._f = None
self._gex_data = b''
def _init_group(self, g, p):
"""Initialize DH group parameters"""
self._g = g
self._p = p
self._q = (p - 1) // 2
def _compute_hash(self, host_key_data, k):
"""Compute a hash of key information associated with the connection"""
hash_obj = self._hash_alg()
hash_obj.update(self._conn.get_hash_prefix())
hash_obj.update(String(host_key_data))
hash_obj.update(self._gex_data)
hash_obj.update(MPInt(self._e))
hash_obj.update(MPInt(self._f))
hash_obj.update(MPInt(k))
return hash_obj.digest()
def _send_init(self):
"""Send a DH init message"""
self._conn.send_packet(Byte(self._init_type), MPInt(self._e))
def _send_reply(self, key_data, sig):
"""Send a DH reply message"""
self._conn.send_packet(Byte(self._reply_type), String(key_data),
MPInt(self._f), String(sig))
def _perform_init(self):
"""Compute e and send init message"""
self._x = randrange(2, self._q)
self._e = pow(self._g, self._x, self._p)
self._send_init()
def _perform_reply(self, key, key_data):
"""Compute f and send reply message"""
if not 1 <= self._e < self._p:
raise DisconnectError(DISC_PROTOCOL_ERROR, 'Kex DH e out of range')
y = randrange(2, self._q)
self._f = pow(self._g, y, self._p)
k = pow(self._e, y, self._p)
if k < 1: # pragma: no cover, shouldn't be possible with valid p
raise DisconnectError(DISC_PROTOCOL_ERROR, 'Kex DH k out of range')
h = self._compute_hash(key_data, k)
self._send_reply(key_data, key.sign(h))
self._conn.send_newkeys(k, h)
def _verify_reply(self, key, key_data, sig):
"""Verify a DH reply message"""
if not 1 <= self._f < self._p:
raise DisconnectError(DISC_PROTOCOL_ERROR, 'Kex DH f out of range')
k = pow(self._f, self._x, self._p)
if k < 1: # pragma: no cover, shouldn't be possible with valid p
raise DisconnectError(DISC_PROTOCOL_ERROR, 'Kex DH k out of range')
h = self._compute_hash(key_data, k)
if not key.verify(h, sig):
raise DisconnectError(DISC_KEY_EXCHANGE_FAILED,
'Key exchange hash mismatch')
self._conn.send_newkeys(k, h)
def _process_init(self, pkttype, packet):
"""Process a DH init message"""
# pylint: disable=unused-argument
if self._conn.is_client() or not self._p:
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Unexpected kex init msg')
self._e = packet.get_mpint()
packet.check_end()
host_key = self._conn.get_server_host_key()
self._perform_reply(host_key, host_key.public_data)
def _process_reply(self, pkttype, packet):
"""Process a DH reply message"""
# pylint: disable=unused-argument
if self._conn.is_server() or not self._p:
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Unexpected kex reply msg')
host_key_data = packet.get_string()
self._f = packet.get_mpint()
sig = packet.get_string()
packet.check_end()
host_key = self._conn.validate_server_host_key(host_key_data)
self._verify_reply(host_key, host_key_data, sig)
def start(self):
"""Start DH key exchange"""
self._perform_init()
class _KexDH(_KexDHBase):
"""Handler for Diffie-Hellman key exchange"""
_init_type = MSG_KEXDH_INIT
_reply_type = MSG_KEXDH_REPLY
def __init__(self, alg, conn, hash_alg, g, p):
super().__init__(alg, conn, hash_alg)
self._init_group(g, p)
packet_handlers = {
MSG_KEXDH_INIT: _KexDHBase._process_init,
MSG_KEXDH_REPLY: _KexDHBase._process_reply
}
class _KexDHGex(_KexDHBase):
"""Handler for Diffie-Hellman group exchange"""
_init_type = MSG_KEX_DH_GEX_INIT
_reply_type = MSG_KEX_DH_GEX_REPLY
_request_type = MSG_KEX_DH_GEX_REQUEST
_group_type = MSG_KEX_DH_GEX_GROUP
def __init__(self, alg, conn, hash_alg, preferred_size=None, max_size=None):
super().__init__(alg, conn, hash_alg)
self._pref_size = preferred_size
self._max_size = max_size
def _send_request(self):
"""Send a DH gex request message"""
if self._pref_size and not self._max_size:
# Send old request message for unit test
request = (Byte(MSG_KEX_DH_GEX_REQUEST_OLD) +
UInt32(self._pref_size))
else:
request = (Byte(self._request_type) + UInt32(KEX_DH_GEX_MIN_SIZE) +
UInt32(self._pref_size or KEX_DH_GEX_PREFERRED_SIZE) +
UInt32(self._max_size or KEX_DH_GEX_MAX_SIZE))
self._gex_data = request[1:]
self._conn.send_packet(request)
def _process_request(self, pkttype, packet):
"""Process a DH gex request message"""
if self._conn.is_client():
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Unexpected kex request msg')
self._gex_data = packet.get_remaining_payload()
if pkttype == MSG_KEX_DH_GEX_REQUEST_OLD:
preferred_size = packet.get_uint32()
max_size = KEX_DH_GEX_MAX_SIZE
else:
_ = packet.get_uint32()
preferred_size = packet.get_uint32()
max_size = packet.get_uint32()
packet.check_end()
g, p = _group1_g, _group1_p
for gex_size, gex_g, gex_p in _dh_gex_groups:
if gex_size > max_size:
break
else:
g, p = gex_g, gex_p
if gex_size >= preferred_size:
break
self._init_group(g, p)
self._gex_data += MPInt(p) + MPInt(g)
self._conn.send_packet(Byte(self._group_type), MPInt(p), MPInt(g))
def _process_group(self, pkttype, packet):
"""Process a DH gex group message"""
# pylint: disable=unused-argument
if self._conn.is_server():
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Unexpected kex group msg')
p = packet.get_mpint()
g = packet.get_mpint()
packet.check_end()
self._init_group(g, p)
self._gex_data += MPInt(p) + MPInt(g)
self._perform_init()
def start(self):
"""Start DH group exchange"""
self._send_request()
packet_handlers = {
MSG_KEX_DH_GEX_REQUEST_OLD: _process_request,
MSG_KEX_DH_GEX_GROUP: _process_group,
MSG_KEX_DH_GEX_INIT: _KexDHBase._process_init,
MSG_KEX_DH_GEX_REPLY: _KexDHBase._process_reply,
MSG_KEX_DH_GEX_REQUEST: _process_request
}
class _KexGSSBase(_KexDHBase):
"""Handler for GSS key exchange"""
def __init__(self, alg, conn, hash_alg, *args):
super().__init__(alg, conn, hash_alg, *args)
self._gss = conn.get_gss_context()
self._token = None
self._host_key_data = b''
self._got_error = False
def _check_secure(self):
"""Check that GSS context is secure enough for key exchange"""
if (not self._gss.provides_mutual_auth or
not self._gss.provides_integrity):
raise DisconnectError(DISC_PROTOCOL_ERROR,
'GSS context not secure')
def _send_init(self):
"""Send a GSS init message"""
if not self._token:
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Empty GSS token in init')
self._conn.send_packet(Byte(MSG_KEXGSS_INIT), String(self._token),
MPInt(self._e))
def _send_reply(self, key_data, sig):
"""Send a GSS reply message"""
if self._token:
token_data = Boolean(True) + String(self._token)
else:
token_data = Boolean(False)
self._conn.send_packet(Byte(MSG_KEXGSS_COMPLETE), MPInt(self._f),
String(sig), token_data)
def _send_continue(self):
"""Send a GSS continue message"""
if not self._token:
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Empty GSS token in continue')
self._conn.send_packet(Byte(MSG_KEXGSS_CONTINUE), String(self._token))
def _process_token(self, token=None):
"""Process a GSS token"""
try:
self._token = self._gss.step(token)
except GSSError as exc:
if self._conn.is_server():
self._conn.send_packet(Byte(MSG_KEXGSS_ERROR),
UInt32(exc.maj_code),
UInt32(exc.min_code),
String(str(exc)),
String(DEFAULT_LANG))
if exc.token:
self._conn.send_packet(Byte(MSG_KEXGSS_CONTINUE),
String(exc.token))
raise DisconnectError(DISC_KEY_EXCHANGE_FAILED, str(exc))
def _process_init(self, pkttype, packet):
"""Process a GSS init message"""
# pylint: disable=unused-argument
if self._conn.is_client() or not self._p:
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Unexpected kexgss init msg')
token = packet.get_string()
self._e = packet.get_mpint()
packet.check_end()
host_key = self._conn.get_server_host_key()
if host_key:
self._host_key_data = host_key.public_data
self._conn.send_packet(Byte(MSG_KEXGSS_HOSTKEY),
String(self._host_key_data))
else:
self._host_key_data = b''
self._process_token(token)
if self._gss.complete:
self._check_secure()
self._perform_reply(self._gss, self._host_key_data)
self._conn.enable_gss_kex_auth()
else:
self._send_continue()
def _process_continue(self, pkttype, packet):
"""Process a GSS continue message"""
# pylint: disable=unused-argument
token = packet.get_string()
packet.check_end()
if self._conn.is_client() and self._gss.complete:
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Unexpected kexgss continue msg')
self._process_token(token)
if self._conn.is_server() and self._gss.complete:
self._check_secure()
self._perform_reply(self._gss, self._host_key_data)
else:
self._send_continue()
def _process_complete(self, pkttype, packet):
"""Process a GSS complete message"""
# pylint: disable=unused-argument
if self._conn.is_server():
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Unexpected kexgss complete msg')
self._f = packet.get_mpint()
mic = packet.get_string()
token_present = packet.get_boolean()
token = packet.get_string() if token_present else None
packet.check_end()
if token:
if self._gss.complete:
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Non-empty token after complete')
self._process_token(token)
if self._token:
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Non-empty token after complete')
if not self._gss.complete:
raise DisconnectError(DISC_PROTOCOL_ERROR,
'GSS exchange failed to complete')
self._check_secure()
self._verify_reply(self._gss, self._host_key_data, mic)
self._conn.enable_gss_kex_auth()
def _process_hostkey(self, pkttype, packet):
"""Process a GSS hostkey message"""
# pylint: disable=unused-argument
self._host_key_data = packet.get_string()
packet.check_end()
def _process_error(self, pkttype, packet):
"""Process a GSS error message"""
# pylint: disable=unused-argument
if self._conn.is_server():
raise DisconnectError(DISC_PROTOCOL_ERROR,
'Unexpected kexgss error msg')
_ = packet.get_uint32() # major_status
_ = packet.get_uint32() # minor_status
msg = packet.get_string()
_ = packet.get_string() # lang
packet.check_end()
logger.warning('GSS error: %s', msg.decode('utf-8', errors='ignore'))
self._got_error = True
def start(self):
"""Start GSS key or group exchange"""
self._process_token()
super().start()
class _KexGSS(_KexGSSBase, _KexDH):
"""Handler for GSS key exchange"""
packet_handlers = {
MSG_KEXGSS_INIT: _KexGSSBase._process_init,
MSG_KEXGSS_CONTINUE: _KexGSSBase._process_continue,
MSG_KEXGSS_COMPLETE: _KexGSSBase._process_complete,
MSG_KEXGSS_HOSTKEY: _KexGSSBase._process_hostkey,
MSG_KEXGSS_ERROR: _KexGSSBase._process_error
}
class _KexGSSGex(_KexGSSBase, _KexDHGex):
"""Handler for GSS group exchange"""
_request_type = MSG_KEXGSS_GROUPREQ
_group_type = MSG_KEXGSS_GROUP
packet_handlers = {
MSG_KEXGSS_INIT: _KexGSSBase._process_init,
MSG_KEXGSS_CONTINUE: _KexGSSBase._process_continue,
MSG_KEXGSS_COMPLETE: _KexGSSBase._process_complete,
MSG_KEXGSS_HOSTKEY: _KexGSSBase._process_hostkey,
MSG_KEXGSS_ERROR: _KexGSSBase._process_error,
MSG_KEXGSS_GROUPREQ: _KexDHGex._process_request,
MSG_KEXGSS_GROUP: _KexDHGex._process_group
}
# pylint: disable=bad-whitespace
for _name, _hash_alg in ((b'sha256', sha256), (b'sha1', sha1)):
register_kex_alg(b'diffie-hellman-group-exchange-' + _name,
_KexDHGex, _hash_alg)
register_gss_kex_alg(b'gss-gex-' + _name, _KexGSSGex, _hash_alg)
for _name, _hash_alg, _g, _p in (
(b'group1-sha1', sha1, _group1_g, _group1_p),
(b'group14-sha1', sha1, _group14_g, _group14_p),
(b'group14-sha256', sha256, _group14_g, _group14_p),
(b'group15-sha512', sha512, _group15_g, _group15_p),
(b'group16-sha512', sha512, _group16_g, _group16_p),
(b'group17-sha512', sha512, _group17_g, _group17_p),
(b'group18-sha512', sha512, _group18_g, _group18_p)):
register_kex_alg(b'diffie-hellman-' + _name, _KexDH, _hash_alg, _g, _p)
register_gss_kex_alg(b'gss-' + _name, _KexGSS, _hash_alg, _g, _p)
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