1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
|
# Copyright (C) 2007-2008 AG Projects. See LICENSE for details.
#
"""GNUTLS connection support"""
__all__ = ['X509Credentials', 'ClientSession', 'ServerSession', 'ServerSessionFactory']
from time import time
from socket import SHUT_RDWR as SOCKET_SHUT_RDWR
from _ctypes import PyObj_FromPtr
from ctypes import *
from gnutls.validators import *
from gnutls.constants import *
from gnutls.crypto import *
from gnutls.errors import *
from gnutls.library.constants import GNUTLS_SERVER, GNUTLS_CLIENT, GNUTLS_CRT_X509
from gnutls.library.constants import GNUTLS_CERT_INVALID, GNUTLS_CERT_REVOKED, GNUTLS_CERT_INSECURE_ALGORITHM
from gnutls.library.constants import GNUTLS_CERT_SIGNER_NOT_FOUND, GNUTLS_CERT_SIGNER_NOT_CA
from gnutls.library.constants import GNUTLS_AL_FATAL, GNUTLS_A_BAD_CERTIFICATE
from gnutls.library.constants import GNUTLS_A_UNKNOWN_CA, GNUTLS_A_INSUFFICIENT_SECURITY
from gnutls.library.constants import GNUTLS_A_CERTIFICATE_EXPIRED, GNUTLS_A_CERTIFICATE_REVOKED
from gnutls.library.constants import GNUTLS_NAME_DNS
from gnutls.library.types import gnutls_certificate_credentials_t, gnutls_session_t, gnutls_x509_crt_t
from gnutls.library.types import gnutls_certificate_server_retrieve_function
from gnutls.library.functions import *
@gnutls_certificate_server_retrieve_function
def _retrieve_server_certificate(c_session, retr_st):
session = PyObj_FromPtr(gnutls_session_get_ptr(c_session))
identity = session.credentials.select_server_identity(session)
retr_st.contents.type = GNUTLS_CRT_X509
retr_st.contents.deinit_all = 0
if identity is None:
retr_st.contents.ncerts = 0
else:
retr_st.contents.ncerts = 1
retr_st.contents.cert.x509.contents = identity.cert._c_object
retr_st.contents.key.x509 = identity.key._c_object
return 0
class _ServerNameIdentities(dict):
"""Used internally by X509Credentials to map server names to X509 identities for the server name extension"""
def __init__(self, identities):
dict.__init__(self)
for identity in identities:
self.add(identity)
def add(self, identity):
for name in identity.cert.alternative_names.dns:
self[name.lower()] = identity
for ip in identity.cert.alternative_names.ip:
self[ip] = identity
subject = identity.cert.subject
if subject.CN is not None:
self[subject.CN.lower()] = identity
def get(self, server_name, default=None):
server_name = server_name.lower()
if server_name in self:
return self[server_name]
for name in (n for n in self if n.startswith('*.')):
suffix = name[1:]
if server_name.endswith(suffix) and '.' not in server_name[:-len(suffix)]:
return self[name]
return default
class X509Credentials(object):
DH_BITS = 1024
RSA_BITS = 1024
dh_params = None
rsa_params = None
def __new__(cls, *args, **kwargs):
c_object = gnutls_certificate_credentials_t()
gnutls_certificate_allocate_credentials(byref(c_object))
instance = object.__new__(cls)
instance.__deinit = gnutls_certificate_free_credentials
instance._c_object = c_object
return instance
@method_args((X509Certificate, none), (X509PrivateKey, none), list_of(X509Certificate), list_of(X509CRL), list_of(X509Identity))
def __init__(self, cert=None, key=None, trusted=[], crl_list=[], identities=[]):
"""Credentials contain a X509 certificate, a private key, a list of trusted CAs and a list of CRLs (all optional).
An optional list of additional X509 identities can be specified for applications that need more that one identity"""
if cert and key:
gnutls_certificate_set_x509_key(self._c_object, byref(cert._c_object), 1, key._c_object)
elif (cert, key) != (None, None):
raise ValueError("Specify neither or both the certificate and private key")
gnutls_certificate_server_set_retrieve_function(self._c_object, _retrieve_server_certificate)
self._max_depth = 5
self._max_bits = 8200
self._type = CRED_CERTIFICATE
self._cert = cert
self._key = key
self._identities = tuple(identities)
self._trusted = ()
self.add_trusted(trusted)
self.crl_list = crl_list
self.server_name_identities = _ServerNameIdentities(identities)
if cert and key:
self.server_name_identities.add(X509Identity(cert, key))
self.session_params = SessionParams(self._type)
def __del__(self):
self.__deinit(self._c_object)
# Methods to alter the credentials at runtime
@method_args(list_of(X509Certificate))
def add_trusted(self, trusted):
size = len(trusted)
if size > 0:
ca_list = (gnutls_x509_crt_t * size)(*[cert._c_object for cert in trusted])
gnutls_certificate_set_x509_trust(self._c_object, cast(byref(ca_list), POINTER(gnutls_x509_crt_t)), size)
self._trusted = self._trusted + tuple(trusted)
def generate_dh_params(self, bits=DH_BITS):
reference = self.dh_params ## keep a reference to preserve it until replaced
X509Credentials.dh_params = DHParams(bits)
del reference
def generate_rsa_params(self, bits=RSA_BITS):
reference = self.rsa_params ## keep a reference to preserve it until replaced
X509Credentials.rsa_params = RSAParams(bits)
del reference
# Properties
@property
def cert(self):
return self._cert
@property
def key(self):
return self._key
@property
def identities(self):
return self._identities
@property
def trusted(self):
return self._trusted
def _get_crl_list(self):
return self._crl_list
@method_args(list_of(X509CRL))
def _set_crl_list(self, crl_list):
self._crl_list = tuple(crl_list)
crl_list = property(_get_crl_list, _set_crl_list)
del _get_crl_list, _set_crl_list
def _get_max_verify_length(self):
return self._max_depth
@method_args(int)
def _set_max_verify_length(self, max_depth):
gnutls_certificate_set_verify_limits(self._c_object, self._max_bits, max_depth)
self._max_depth = max_depth
max_verify_length = property(_get_max_verify_length, _set_max_verify_length)
del _get_max_verify_length, _set_max_verify_length
def _get_max_verify_bits(self):
return self._max_bits
@method_args(int)
def _set_max_verify_bits(self, max_bits):
gnutls_certificate_set_verify_limits(self._c_object, max_bits, self._max_depth)
self._max_bits = max_bits
max_verify_bits = property(_get_max_verify_bits, _set_max_verify_bits)
del _get_max_verify_bits, _set_max_verify_bits
# Methods to select and validate certificates
def check_certificate(self, cert, cert_name='certificate'):
"""Verify activation, expiration and revocation for the given certificate"""
now = time()
if cert.activation_time > now:
raise CertificateExpiredError("%s is not yet activated" % cert_name)
if cert.expiration_time < now:
raise CertificateExpiredError("%s has expired" % cert_name)
for crl in self.crl_list:
crl.check_revocation(cert, cert_name=cert_name)
def select_server_identity(self, session):
"""Select which identity the server will use for a given session. The default selection algorithm uses
the server name extension. A subclass can overwrite it if a different selection algorithm is desired."""
server_name = session.server_name
if server_name is not None:
return self.server_name_identities.get(server_name)
elif self.cert and self.key:
return self ## since we have the cert and key attributes we can behave like a X509Identity
else:
return None
class SessionParams(object):
_default_kx_algorithms = {
CRED_CERTIFICATE: (KX_RSA, KX_DHE_DSS, KX_DHE_RSA),
CRED_ANON: (KX_ANON_DH,)}
_all_kx_algorithms = {
CRED_CERTIFICATE: set((KX_RSA, KX_DHE_DSS, KX_DHE_RSA, KX_RSA_EXPORT)),
CRED_ANON: set((KX_ANON_DH,))}
def __new__(cls, credentials_type):
if credentials_type not in cls._default_kx_algorithms:
raise TypeError("Unknown credentials type: %r" % credentials_type)
return object.__new__(cls)
def __init__(self, credentials_type):
self._credentials_type = credentials_type
self._protocols = (PROTO_TLS1_1, PROTO_TLS1_0, PROTO_SSL3)
self._kx_algorithms = self._default_kx_algorithms[credentials_type]
self._ciphers = (CIPHER_AES_128_CBC, CIPHER_3DES_CBC, CIPHER_ARCFOUR_128)
self._mac_algorithms = (MAC_SHA1, MAC_MD5, MAC_RMD160)
self._compressions = (COMP_NULL,)
def _get_protocols(self):
return self._protocols
def _set_protocols(self, protocols):
self._protocols = ProtocolListValidator(protocols)
protocols = property(_get_protocols, _set_protocols)
del _get_protocols, _set_protocols
def _get_kx_algorithms(self):
return self._kx_algorithms
def _set_kx_algorithms(self, algorithms):
cred_type = self._credentials_type
algorithms = KeyExchangeListValidator(algorithms)
invalid = set(algorithms) - self._all_kx_algorithms[cred_type]
if invalid:
raise ValueError("Cannot specify %r with %r credentials" % (list(invalid), cred_type))
self._kx_algorithms = algorithms
kx_algorithms = property(_get_kx_algorithms, _set_kx_algorithms)
del _get_kx_algorithms, _set_kx_algorithms
def _get_ciphers(self):
return self._ciphers
def _set_ciphers(self, ciphers):
self._ciphers = CipherListValidator(ciphers)
ciphers = property(_get_ciphers, _set_ciphers)
del _get_ciphers, _set_ciphers
def _get_mac_algorithms(self):
return self._mac_algorithms
def _set_mac_algorithms(self, algorithms):
self._mac_algorithms = MACListValidator(algorithms)
mac_algorithms = property(_get_mac_algorithms, _set_mac_algorithms)
del _get_mac_algorithms, _set_mac_algorithms
def _get_compressions(self):
return self._compressions
def _set_compressions(self, compressions):
self._compressions = CompressionListValidator(compressions)
compressions = property(_get_compressions, _set_compressions)
del _get_compressions, _set_compressions
class Session(object):
"""Abstract class representing a TLS session created from a TCP socket
and a Credentials object."""
session_type = None ## placeholder for GNUTLS_SERVER or GNUTLS_CLIENT as defined by subclass
def __new__(cls, *args, **kwargs):
if cls is Session:
raise RuntimeError("Session cannot be instantiated directly")
instance = object.__new__(cls)
instance.__deinit = gnutls_deinit
instance._c_object = gnutls_session_t()
return instance
def __init__(self, socket, credentials):
gnutls_init(byref(self._c_object), self.session_type)
## Store a pointer to self on the C session
gnutls_session_set_ptr(self._c_object, id(self))
# gnutls_dh_set_prime_bits(session, DH_BITS)?
gnutls_transport_set_ptr(self._c_object, socket.fileno())
gnutls_handshake_set_private_extensions(self._c_object, 1)
self.socket = socket
self.credentials = credentials
self._update_params()
def __del__(self):
self.__deinit(self._c_object)
def __getattr__(self, name):
## Generic wrapper for the underlying socket methods and attributes.
return getattr(self.socket, name)
# Session properties
def _get_credentials(self):
return self._credentials
@method_args(X509Credentials)
def _set_credentials(self, credentials):
## Release all credentials, otherwise gnutls will only release an existing credential of
## the same type as the one being set and we can end up with multiple credentials in C.
gnutls_credentials_clear(self._c_object)
gnutls_credentials_set(self._c_object, credentials._type, cast(credentials._c_object, c_void_p))
self._credentials = credentials
credentials = property(_get_credentials, _set_credentials)
del _get_credentials, _set_credentials
@property
def protocol(self):
return gnutls_protocol_get_name(gnutls_protocol_get_version(self._c_object))
@property
def kx_algorithm(self):
return gnutls_kx_get_name(gnutls_kx_get(self._c_object))
@property
def cipher(self):
return gnutls_cipher_get_name(gnutls_cipher_get(self._c_object))
@property
def mac_algorithm(self):
return gnutls_mac_get_name(gnutls_mac_get(self._c_object))
@property
def compression(self):
return gnutls_compression_get_name(gnutls_compression_get(self._c_object))
@property
def peer_certificate(self):
if gnutls_certificate_type_get(self._c_object) != GNUTLS_CRT_X509:
return None
list_size = c_uint()
cert_list = gnutls_certificate_get_peers(self._c_object, byref(list_size))
if list_size.value == 0:
return None
cert = cert_list[0]
return X509Certificate(string_at(cert.data, cert.size), X509_FMT_DER)
# Status checking after an operation was interrupted (these properties are
# only useful to check after an operation was interrupted, otherwise their
# value is meaningless).
@property
def interrupted_while_writing(self):
"""True if an operation was interrupted while writing"""
return gnutls_record_get_direction(self._c_object)==1
@property
def interrupted_while_reading(self):
"""True if an operation was interrupted while reading"""
return gnutls_record_get_direction(self._c_object)==0
# Session methods
def _update_params(self):
"""Update the priorities of the session params using the credentials."""
def c_priority_list(priorities):
size = len(priorities) + 1
return (c_int * size)(*priorities)
session_params = self.credentials.session_params
# protocol order in the priority list is irrelevant (it always uses newer protocols first)
# the protocol list only specifies what protocols are to be enabled.
gnutls_protocol_set_priority(self._c_object, c_priority_list(session_params.protocols))
gnutls_kx_set_priority(self._c_object, c_priority_list(session_params.kx_algorithms))
gnutls_cipher_set_priority(self._c_object, c_priority_list(session_params.ciphers))
gnutls_mac_set_priority(self._c_object, c_priority_list(session_params.mac_algorithms))
gnutls_compression_set_priority(self._c_object, c_priority_list(session_params.compressions))
def handshake(self):
gnutls_handshake(self._c_object)
#@method_args((basestring, buffer))
def send(self, data):
data = str(data)
return gnutls_record_send(self._c_object, data, len(data))
def sendall(self, data):
size = len(data)
while size > 0:
sent = self.send(data[-size:])
size -= sent
def recv(self, limit):
data = create_string_buffer(limit)
size = gnutls_record_recv(self._c_object, data, limit)
return data[:size]
def send_alert(self, exception):
alertdict = {
CertificateError: GNUTLS_A_BAD_CERTIFICATE,
CertificateAuthorityError: GNUTLS_A_UNKNOWN_CA,
CertificateSecurityError: GNUTLS_A_INSUFFICIENT_SECURITY,
CertificateExpiredError: GNUTLS_A_CERTIFICATE_EXPIRED,
CertificateRevokedError: GNUTLS_A_CERTIFICATE_REVOKED}
alert = alertdict.get(exception.__class__)
if alert:
gnutls_alert_send(self._c_object, GNUTLS_AL_FATAL, alert)
@method_args(one_of(SHUT_RDWR, SHUT_WR))
def bye(self, how=SHUT_RDWR):
gnutls_bye(self._c_object, how)
def shutdown(self, how=SOCKET_SHUT_RDWR):
self.socket.shutdown(how)
def close(self):
self.socket.close()
def verify_peer(self):
status = c_uint()
gnutls_certificate_verify_peers2(self._c_object, byref(status))
status = status.value
if status & GNUTLS_CERT_INVALID:
raise CertificateError("peer certificate is invalid")
elif status & GNUTLS_CERT_SIGNER_NOT_FOUND:
raise CertificateAuthorityError("peer certificate signer not found")
elif status & GNUTLS_CERT_SIGNER_NOT_CA:
raise CertificateAuthorityError("peer certificate signer is not a CA")
elif status & GNUTLS_CERT_INSECURE_ALGORITHM:
raise CertificateSecurityError("peer certificate uses an insecure algorithm")
elif status & GNUTLS_CERT_REVOKED:
raise CertificateRevokedError("peer certificate was revoked")
class ClientSession(Session):
session_type = GNUTLS_CLIENT
def __init__(self, socket, credentials, server_name=None):
Session.__init__(self, socket, credentials)
self._server_name = None
if server_name is not None:
self.server_name = server_name
def _get_server_name(self):
return self._server_name
@method_args(str)
def _set_server_name(self, server_name):
gnutls_server_name_set(self._c_object, GNUTLS_NAME_DNS, c_char_p(server_name), len(server_name))
self._server_name = server_name
server_name = property(_get_server_name, _set_server_name)
del _get_server_name, _set_server_name
class ServerSession(Session):
session_type = GNUTLS_SERVER
def __init__(self, socket, credentials):
Session.__init__(self, socket, credentials)
gnutls_certificate_server_set_request(self._c_object, CERT_REQUEST)
@property
def server_name(self):
data_length = c_size_t(256)
data = create_string_buffer(data_length.value)
hostname_type = c_uint()
for i in xrange(2**16):
try:
gnutls_server_name_get(self._c_object, data, byref(data_length), byref(hostname_type), i)
except RequestedDataNotAvailable:
break
except MemoryError:
data_length.value += 1 ## one extra byte for the terminating 0
data = create_string_buffer(data_length.value)
gnutls_server_name_get(self._c_object, data, byref(data_length), byref(hostname_type), i)
if hostname_type.value != GNUTLS_NAME_DNS:
continue
return data.value
return None
class ServerSessionFactory(object):
def __init__(self, socket, credentials, session_class=ServerSession):
if not issubclass(session_class, ServerSession):
raise TypeError, "session_class must be a subclass of ServerSession"
self.socket = socket
self.credentials = credentials
self.session_class = session_class
def __getattr__(self, name):
## Generic wrapper for the underlying socket methods and attributes
return getattr(self.socket, name)
def bind(self, address):
self.socket.bind(address)
def listen(self, backlog):
self.socket.listen(backlog)
def accept(self):
new_sock, address = self.socket.accept()
session = self.session_class(new_sock, self.credentials)
return (session, address)
def shutdown(self, how=SOCKET_SHUT_RDWR):
self.socket.shutdown(how)
def close(self):
self.socket.close()
|