def __init__(self, msg=None, data=None, filename=None, password=None, vals=None, file_obj=None):
self.p = None
self.q = None
self.g = None
self.y = None
self.x = None
if file_obj is not None:
self._from_private_key(file_obj, password)
return
if filename is not None:
self._from_private_key_file(filename, password)
return
if (msg is None) and (data is not None):
msg = Message(data)
if vals is not None:
self.p, self.q, self.g, self.y = vals
else:
if msg is None:
raise SSHException('Key object may not be empty')
if msg.get_string() != 'ssh-dss':
raise SSHException('Invalid key')
self.p = msg.get_mpint()
self.q = msg.get_mpint()
self.g = msg.get_mpint()
self.y = msg.get_mpint()
self.size = util.bit_length(self.p)
def _disconnect_no_more_auth(self):
m = Message()
m.add_byte(chr(MSG_DISCONNECT))
m.add_int(DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE)
m.add_string('No more auth methods available')
m.add_string('en')
self.transport._send_message(m)
self.transport.close()
def _disconnect_service_not_available(self):
m = Message()
m.add_byte(chr(MSG_DISCONNECT))
m.add_int(DISCONNECT_SERVICE_NOT_AVAILABLE)
m.add_string('Service not available')
m.add_string('en')
self.transport._send_message(m)
self.transport.close()
def sign_ssh_data(self, randpool, data):
msg = Message()
msg.add_byte(chr(SSH2_AGENTC_SIGN_REQUEST))
msg.add_string(self.blob)
msg.add_string(data)
msg.add_int(0)
ptype, result = self.agent._send_message(msg)
if ptype != SSH2_AGENT_SIGN_RESPONSE:
raise SSHException('key cannot be used for signing')
return result.get_string()
def __str__(self):
m = Message()
m.add_string('ssh-dss')
m.add_mpint(self.p)
m.add_mpint(self.q)
m.add_mpint(self.g)
m.add_mpint(self.y)
return str(m)
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_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(chr(_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)
def sign_ssh_data(self, rpool, data):
digest = SHA.new(data).digest()
rsa = RSA.construct((long(self.n), long(self.e), long(self.d)))
sig = util.deflate_long(rsa.sign(self._pkcs1imify(digest), '')[0], 0)
m = Message()
m.add_string('ssh-rsa')
m.add_string(sig)
return m
def _parse_service_request(self, m):
service = m.get_string()
if self.transport.server_mode and (service == 'ssh-userauth'):
# accepted
m = Message()
m.add_byte(chr(MSG_SERVICE_ACCEPT))
m.add_string(service)
self.transport._send_message(m)
return
# dunno this one
self._disconnect_service_not_available()
def _parse_userauth_info_request(self, m):
if self.auth_method != 'keyboard-interactive':
raise SSHException('Illegal info request from server')
title = m.get_string()
instructions = m.get_string()
m.get_string() # lang
prompts = m.get_int()
prompt_list = []
for i in range(prompts):
prompt_list.append((m.get_string(), m.get_boolean()))
response_list = self.interactive_handler(title, instructions,
prompt_list)
m = Message()
m.add_byte(chr(MSG_USERAUTH_INFO_RESPONSE))
m.add_int(len(response_list))
for r in response_list:
m.add_string(r)
self.transport._send_message(m)
def _send_server_version(self):
# winscp will freak out if the server sends version info before the
# client finishes sending INIT.
t, data = self._read_packet()
if t != CMD_INIT:
raise SFTPError('Incompatible sftp protocol')
version = struct.unpack('>I', data[:4])[0]
# advertise that we support "check-file"
extension_pairs = [ 'check-file', 'md5,sha1' ]
msg = Message()
msg.add_int(_VERSION)
msg.add(*extension_pairs)
self._send_packet(CMD_VERSION, str(msg))
return version
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_kexdh_gex_group(self, m):
self.p = m.get_mpint()
self.g = m.get_mpint()
# reject if p's bit length < 1024 or > 8192
bitlen = util.bit_length(self.p)
if (bitlen < 1024) or (bitlen > 8192):
raise SSHException(
'Server-generated gex p (don\'t ask) is out of range (%d bits)'
% bitlen)
self.transport._log(DEBUG, 'Got server p (%d bits)' % bitlen)
self._generate_x()
# now compute e = g^x mod p
self.e = pow(self.g, self.x, self.p)
m = Message()
m.add_byte(chr(_MSG_KEXDH_GEX_INIT))
m.add_mpint(self.e)
self.transport._send_message(m)
self.transport._expect_packet(_MSG_KEXDH_GEX_REPLY)
def sign_ssh_data(self, rpool, data):
digest = SHA.new(data).digest()
dss = DSA.construct((long(self.y), long(self.g), long(self.p), long(self.q), long(self.x)))
# generate a suitable k
qsize = len(util.deflate_long(self.q, 0))
while True:
k = util.inflate_long(rpool.get_bytes(qsize), 1)
if (k > 2) and (k < self.q):
break
r, s = dss.sign(util.inflate_long(digest, 1), k)
m = Message()
m.add_string('ssh-dss')
# apparently, in rare cases, r or s may be shorter than 20 bytes!
rstr = util.deflate_long(r, 0)
sstr = util.deflate_long(s, 0)
if len(rstr) < 20:
rstr = '\x00' * (20 - len(rstr)) + rstr
if len(sstr) < 20:
sstr = '\x00' * (20 - len(sstr)) + sstr
m.add_string(rstr + sstr)
return m
def _parse_kexdh_gex_request_old(self, m):
# same as above, but without min_bits or max_bits (used by older clients like putty)
self.preferred_bits = m.get_int()
# smoosh the user's preferred size into our own limits
if self.preferred_bits > self.max_bits:
self.preferred_bits = self.max_bits
if self.preferred_bits < self.min_bits:
self.preferred_bits = self.min_bits
# 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 bits)' % (self.preferred_bits, ))
self.g, self.p = pack.get_modulus(self.min_bits, self.preferred_bits,
self.max_bits)
m = Message()
m.add_byte(chr(_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)
self.old_style = True
def read_message(self):
"""
Only one thread should ever be in this function (no other locking is
done).
@raise SSHException: if the packet is mangled
@raise NeedRekeyException: if the transport should rekey
"""
header = self.read_all(self.__block_size_in, check_rekey=True)
if self.__block_engine_in != None:
header = self.__block_engine_in.decrypt(header)
if self.__dump_packets:
self._log(DEBUG, util.format_binary(header, 'IN: '))
packet_size = struct.unpack('>I', header[:4])[0]
# leftover contains decrypted bytes from the first block (after the length field)
leftover = header[4:]
if (packet_size - len(leftover)) % self.__block_size_in != 0:
raise SSHException('Invalid packet blocking')
buf = self.read_all(packet_size + self.__mac_size_in - len(leftover))
packet = buf[:packet_size - len(leftover)]
post_packet = buf[packet_size - len(leftover):]
if self.__block_engine_in != None:
packet = self.__block_engine_in.decrypt(packet)
if self.__dump_packets:
self._log(DEBUG, util.format_binary(packet, 'IN: '))
packet = leftover + packet
if self.__mac_size_in > 0:
mac = post_packet[:self.__mac_size_in]
mac_payload = struct.pack('>II', self.__sequence_number_in,
packet_size) + packet
my_mac = compute_hmac(self.__mac_key_in, mac_payload,
self.__mac_engine_in)[:self.__mac_size_in]
if my_mac != mac:
raise SSHException('Mismatched MAC')
padding = ord(packet[0])
payload = packet[1:packet_size - padding]
randpool.add_event()
if self.__dump_packets:
self._log(
DEBUG,
'Got payload (%d bytes, %d padding)' % (packet_size, padding))
if self.__compress_engine_in is not None:
payload = self.__compress_engine_in(payload)
msg = Message(payload[1:])
msg.seqno = self.__sequence_number_in
self.__sequence_number_in = (self.__sequence_number_in +
1) & 0xffffffffL
# check for rekey
self.__received_bytes += packet_size + self.__mac_size_in + 4
self.__received_packets += 1
if self.__need_rekey:
# we've asked to rekey -- give them 20 packets to comply before
# dropping the connection
self.__received_packets_overflow += 1
if self.__received_packets_overflow >= 20:
raise SSHException(
'Remote transport is ignoring rekey requests')
elif (self.__received_packets >= self.REKEY_PACKETS) or \
(self.__received_bytes >= self.REKEY_BYTES):
# only ask once for rekeying
self._log(
DEBUG, 'Rekeying (hit %d packets, %d bytes received)' %
(self.__received_packets, self.__received_bytes))
self.__received_packets_overflow = 0
self._trigger_rekey()
cmd = ord(payload[0])
if cmd in MSG_NAMES:
cmd_name = MSG_NAMES[cmd]
else:
cmd_name = '$%x' % cmd
if self.__dump_packets:
self._log(DEBUG,
'Read packet <%s>, length %d' % (cmd_name, len(payload)))
return cmd, msg
def __init__(self, agent, blob):
self.agent = agent
self.blob = blob
self.name = Message(blob).get_string()
def _parse_userauth_request(self, m):
if not self.transport.server_mode:
# er, uh... what?
m = Message()
m.add_byte(chr(MSG_USERAUTH_FAILURE))
m.add_string('none')
m.add_boolean(0)
self.transport._send_message(m)
return
if self.authenticated:
# ignore
return
username = m.get_string()
service = m.get_string()
method = m.get_string()
self.transport._log(
DEBUG, 'Auth request (type=%s) service=%s, username=%s' %
(method, service, username))
if service != 'ssh-connection':
self._disconnect_service_not_available()
return
if (self.auth_username
is not None) and (self.auth_username != username):
self.transport._log(
WARNING,
'Auth rejected because the client attempted to change username in mid-flight'
)
self._disconnect_no_more_auth()
return
self.auth_username = username
if method == 'none':
result = self.transport.server_object.check_auth_none(username)
elif method == 'password':
changereq = m.get_boolean()
password = m.get_string()
try:
password = password.decode('UTF-8')
except UnicodeError:
# some clients/servers expect non-utf-8 passwords!
# in this case, just return the raw byte string.
pass
if changereq:
# always treated as failure, since we don't support changing passwords, but collect
# the list of valid auth types from the callback anyway
self.transport._log(
DEBUG, 'Auth request to change passwords (rejected)')
newpassword = m.get_string()
try:
newpassword = newpassword.decode('UTF-8', 'replace')
except UnicodeError:
pass
result = AUTH_FAILED
else:
result = self.transport.server_object.check_auth_password(
username, password)
elif method == 'publickey':
sig_attached = m.get_boolean()
keytype = m.get_string()
keyblob = m.get_string()
try:
key = self.transport._key_info[keytype](Message(keyblob))
except SSHException, e:
self.transport._log(INFO,
'Auth rejected: public key: %s' % str(e))
key = None
except:
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()
def _send_auth_result(self, username, method, result):
# okay, send result
m = Message()
if result == AUTH_SUCCESSFUL:
self.transport._log(INFO, 'Auth granted (%s).' % method)
m.add_byte(chr(MSG_USERAUTH_SUCCESS))
self.authenticated = True
else:
self.transport._log(INFO, 'Auth rejected (%s).' % method)
m.add_byte(chr(MSG_USERAUTH_FAILURE))
m.add_string(
self.transport.server_object.get_allowed_auths(username))
if result == AUTH_PARTIALLY_SUCCESSFUL:
m.add_boolean(1)
else:
m.add_boolean(0)
self.auth_fail_count += 1
self.transport._send_message(m)
if self.auth_fail_count >= 10:
self._disconnect_no_more_auth()
if result == AUTH_SUCCESSFUL:
self.transport._auth_trigger()
def _interactive_query(self, q):
# make interactive query instead of response
m = Message()
m.add_byte(chr(MSG_USERAUTH_INFO_REQUEST))
m.add_string(q.name)
m.add_string(q.instructions)
m.add_string('')
m.add_int(len(q.prompts))
for p in q.prompts:
m.add_string(p[0])
m.add_boolean(p[1])
self.transport._send_message(m)
def _parse_service_accept(self, m):
service = m.get_string()
if service == 'ssh-userauth':
self.transport._log(DEBUG, 'userauth is OK')
m = Message()
m.add_byte(chr(MSG_USERAUTH_REQUEST))
m.add_string(self.username)
m.add_string('ssh-connection')
m.add_string(self.auth_method)
if self.auth_method == 'password':
m.add_boolean(False)
password = self.password
if isinstance(password, unicode):
password = password.encode('UTF-8')
m.add_string(password)
elif self.auth_method == 'publickey':
m.add_boolean(True)
m.add_string(self.private_key.get_name())
m.add_string(str(self.private_key))
blob = self._get_session_blob(self.private_key,
'ssh-connection', self.username)
sig = self.private_key.sign_ssh_data(self.transport.randpool,
blob)
m.add_string(str(sig))
elif self.auth_method == 'keyboard-interactive':
m.add_string('')
m.add_string(self.submethods)
elif self.auth_method == 'none':
pass
else:
raise SSHException('Unknown auth method "%s"' %
self.auth_method)
self.transport._send_message(m)
else:
self.transport._log(DEBUG,
'Service request "%s" accepted (?)' % service)
def __str__(self):
m = Message()
m.add_string('ssh-rsa')
m.add_mpint(self.e)
m.add_mpint(self.n)
return str(m)
def start_kex(self, _test_old_style=False):
if self.transport.server_mode:
self.transport._expect_packet(_MSG_KEXDH_GEX_REQUEST,
_MSG_KEXDH_GEX_REQUEST_OLD)
return
# request a bit range: we accept (min_bits) to (max_bits), but prefer
# (preferred_bits). according to the spec, we shouldn't pull the
# minimum up above 1024.
m = Message()
if _test_old_style:
# only used for unit tests: we shouldn't ever send this
m.add_byte(chr(_MSG_KEXDH_GEX_REQUEST_OLD))
m.add_int(self.preferred_bits)
self.old_style = True
else:
m.add_byte(chr(_MSG_KEXDH_GEX_REQUEST))
m.add_int(self.min_bits)
m.add_int(self.preferred_bits)
m.add_int(self.max_bits)
self.transport._send_message(m)
self.transport._expect_packet(_MSG_KEXDH_GEX_GROUP)
except:
self.transport._log(
INFO, 'Auth rejected: unsupported or mangled public key')
key = None
if key is None:
self._disconnect_no_more_auth()
return
# first check if this key is okay... if not, we can skip the verify
result = self.transport.server_object.check_auth_publickey(
username, key)
if result != AUTH_FAILED:
# key is okay, verify it
if not sig_attached:
# client wants to know if this key is acceptable, before it
# signs anything... send special "ok" message
m = Message()
m.add_byte(chr(MSG_USERAUTH_PK_OK))
m.add_string(keytype)
m.add_string(keyblob)
self.transport._send_message(m)
return
sig = Message(m.get_string())
blob = self._get_session_blob(key, service, username)
if not key.verify_ssh_sig(blob, sig):
self.transport._log(INFO,
'Auth rejected: invalid signature')
result = AUTH_FAILED
elif method == 'keyboard-interactive':
lang = m.get_string()
submethods = m.get_string()
result = self.transport.server_object.check_auth_interactive(
def _request_auth(self):
m = Message()
m.add_byte(chr(MSG_SERVICE_REQUEST))
m.add_string('ssh-userauth')
self.transport._send_message(m)
def _send_message(self, msg):
msg = str(msg)
self.conn.send(struct.pack('>I', len(msg)) + msg)
l = self._read_all(4)
msg = Message(self._read_all(struct.unpack('>I', l)[0]))
return ord(msg.get_byte()), msg
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 = str(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(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_GEX_REPLY))
m.add_string(key)
m.add_mpint(self.f)
m.add_string(str(sig))
self.transport._send_message(m)
self.transport._activate_outbound()
def _get_session_blob(self, key, service, username):
m = Message()
m.add_string(self.transport.session_id)
m.add_byte(chr(MSG_USERAUTH_REQUEST))
m.add_string(username)
m.add_string(service)
m.add_string('publickey')
m.add_boolean(1)
m.add_string(key.get_name())
m.add_string(str(key))
return str(m)
def _parse_kexdh_gex_reply(self, m):
host_key = m.get_string()
self.f = m.get_mpint()
sig = m.get_string()
if (self.f < 1) or (self.f > self.p - 1):
raise SSHException('Server kex "f" is out of range')
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 || min || n || max || p || g || 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,
host_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)
self.transport._set_K_H(K, SHA.new(str(hm)).digest())
self.transport._verify_key(host_key, sig)
self.transport._activate_outbound()
