-
-
Notifications
You must be signed in to change notification settings - Fork 141
/
ocsp.py
703 lines (536 loc) · 18.6 KB
/
ocsp.py
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
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
# coding: utf-8
"""
ASN.1 type classes for the online certificate status protocol (OCSP). Exports
the following items:
- OCSPRequest()
- OCSPResponse()
Other type classes are defined that help compose the types listed above.
"""
from __future__ import unicode_literals, division, absolute_import, print_function
from ._errors import unwrap
from .algos import DigestAlgorithm, SignedDigestAlgorithm
from .core import (
Boolean,
Choice,
Enumerated,
GeneralizedTime,
IA5String,
Integer,
Null,
ObjectIdentifier,
OctetBitString,
OctetString,
ParsableOctetString,
Sequence,
SequenceOf,
)
from .crl import AuthorityInfoAccessSyntax, CRLReason
from .keys import PublicKeyAlgorithm
from .x509 import Certificate, GeneralName, GeneralNames, Name
# The structures in this file are taken from https://tools.ietf.org/html/rfc6960
class Version(Integer):
_map = {
0: 'v1'
}
class CertId(Sequence):
_fields = [
('hash_algorithm', DigestAlgorithm),
('issuer_name_hash', OctetString),
('issuer_key_hash', OctetString),
('serial_number', Integer),
]
class ServiceLocator(Sequence):
_fields = [
('issuer', Name),
('locator', AuthorityInfoAccessSyntax),
]
class RequestExtensionId(ObjectIdentifier):
_map = {
'1.3.6.1.5.5.7.48.1.7': 'service_locator',
}
class RequestExtension(Sequence):
_fields = [
('extn_id', RequestExtensionId),
('critical', Boolean, {'default': False}),
('extn_value', ParsableOctetString),
]
_oid_pair = ('extn_id', 'extn_value')
_oid_specs = {
'service_locator': ServiceLocator,
}
class RequestExtensions(SequenceOf):
_child_spec = RequestExtension
class Request(Sequence):
_fields = [
('req_cert', CertId),
('single_request_extensions', RequestExtensions, {'explicit': 0, 'optional': True}),
]
_processed_extensions = False
_critical_extensions = None
_service_locator_value = None
def _set_extensions(self):
"""
Sets common named extensions to private attributes and creates a list
of critical extensions
"""
self._critical_extensions = set()
for extension in self['single_request_extensions']:
name = extension['extn_id'].native
attribute_name = '_%s_value' % name
if hasattr(self, attribute_name):
setattr(self, attribute_name, extension['extn_value'].parsed)
if extension['critical'].native:
self._critical_extensions.add(name)
self._processed_extensions = True
@property
def critical_extensions(self):
"""
Returns a set of the names (or OID if not a known extension) of the
extensions marked as critical
:return:
A set of unicode strings
"""
if not self._processed_extensions:
self._set_extensions()
return self._critical_extensions
@property
def service_locator_value(self):
"""
This extension is used when communicating with an OCSP responder that
acts as a proxy for OCSP requests
:return:
None or a ServiceLocator object
"""
if self._processed_extensions is False:
self._set_extensions()
return self._service_locator_value
class Requests(SequenceOf):
_child_spec = Request
class ResponseType(ObjectIdentifier):
_map = {
'1.3.6.1.5.5.7.48.1.1': 'basic_ocsp_response',
}
class AcceptableResponses(SequenceOf):
_child_spec = ResponseType
class PreferredSignatureAlgorithm(Sequence):
_fields = [
('sig_identifier', SignedDigestAlgorithm),
('cert_identifier', PublicKeyAlgorithm, {'optional': True}),
]
class PreferredSignatureAlgorithms(SequenceOf):
_child_spec = PreferredSignatureAlgorithm
class TBSRequestExtensionId(ObjectIdentifier):
_map = {
'1.3.6.1.5.5.7.48.1.2': 'nonce',
'1.3.6.1.5.5.7.48.1.4': 'acceptable_responses',
'1.3.6.1.5.5.7.48.1.8': 'preferred_signature_algorithms',
}
class TBSRequestExtension(Sequence):
_fields = [
('extn_id', TBSRequestExtensionId),
('critical', Boolean, {'default': False}),
('extn_value', ParsableOctetString),
]
_oid_pair = ('extn_id', 'extn_value')
_oid_specs = {
'nonce': OctetString,
'acceptable_responses': AcceptableResponses,
'preferred_signature_algorithms': PreferredSignatureAlgorithms,
}
class TBSRequestExtensions(SequenceOf):
_child_spec = TBSRequestExtension
class TBSRequest(Sequence):
_fields = [
('version', Version, {'explicit': 0, 'default': 'v1'}),
('requestor_name', GeneralName, {'explicit': 1, 'optional': True}),
('request_list', Requests),
('request_extensions', TBSRequestExtensions, {'explicit': 2, 'optional': True}),
]
class Certificates(SequenceOf):
_child_spec = Certificate
class Signature(Sequence):
_fields = [
('signature_algorithm', SignedDigestAlgorithm),
('signature', OctetBitString),
('certs', Certificates, {'explicit': 0, 'optional': True}),
]
class OCSPRequest(Sequence):
_fields = [
('tbs_request', TBSRequest),
('optional_signature', Signature, {'explicit': 0, 'optional': True}),
]
_processed_extensions = False
_critical_extensions = None
_nonce_value = None
_acceptable_responses_value = None
_preferred_signature_algorithms_value = None
def _set_extensions(self):
"""
Sets common named extensions to private attributes and creates a list
of critical extensions
"""
self._critical_extensions = set()
for extension in self['tbs_request']['request_extensions']:
name = extension['extn_id'].native
attribute_name = '_%s_value' % name
if hasattr(self, attribute_name):
setattr(self, attribute_name, extension['extn_value'].parsed)
if extension['critical'].native:
self._critical_extensions.add(name)
self._processed_extensions = True
@property
def critical_extensions(self):
"""
Returns a set of the names (or OID if not a known extension) of the
extensions marked as critical
:return:
A set of unicode strings
"""
if not self._processed_extensions:
self._set_extensions()
return self._critical_extensions
@property
def nonce_value(self):
"""
This extension is used to prevent replay attacks by including a unique,
random value with each request/response pair
:return:
None or an OctetString object
"""
if self._processed_extensions is False:
self._set_extensions()
return self._nonce_value
@property
def acceptable_responses_value(self):
"""
This extension is used to allow the client and server to communicate
with alternative response formats other than just basic_ocsp_response,
although no other formats are defined in the standard.
:return:
None or an AcceptableResponses object
"""
if self._processed_extensions is False:
self._set_extensions()
return self._acceptable_responses_value
@property
def preferred_signature_algorithms_value(self):
"""
This extension is used by the client to define what signature algorithms
are preferred, including both the hash algorithm and the public key
algorithm, with a level of detail down to even the public key algorithm
parameters, such as curve name.
:return:
None or a PreferredSignatureAlgorithms object
"""
if self._processed_extensions is False:
self._set_extensions()
return self._preferred_signature_algorithms_value
class OCSPResponseStatus(Enumerated):
_map = {
0: 'successful',
1: 'malformed_request',
2: 'internal_error',
3: 'try_later',
5: 'sign_required',
6: 'unauthorized',
}
class ResponderId(Choice):
_alternatives = [
('by_name', Name, {'explicit': 1}),
('by_key', OctetString, {'explicit': 2}),
]
# Custom class to return a meaningful .native attribute from CertStatus()
class StatusGood(Null):
def set(self, value):
"""
Sets the value of the object
:param value:
None or 'good'
"""
if value is not None and value != 'good' and not isinstance(value, Null):
raise ValueError(unwrap(
'''
value must be one of None, "good", not %s
''',
repr(value)
))
self.contents = b''
@property
def native(self):
return 'good'
# Custom class to return a meaningful .native attribute from CertStatus()
class StatusUnknown(Null):
def set(self, value):
"""
Sets the value of the object
:param value:
None or 'unknown'
"""
if value is not None and value != 'unknown' and not isinstance(value, Null):
raise ValueError(unwrap(
'''
value must be one of None, "unknown", not %s
''',
repr(value)
))
self.contents = b''
@property
def native(self):
return 'unknown'
class RevokedInfo(Sequence):
_fields = [
('revocation_time', GeneralizedTime),
('revocation_reason', CRLReason, {'explicit': 0, 'optional': True}),
]
class CertStatus(Choice):
_alternatives = [
('good', StatusGood, {'implicit': 0}),
('revoked', RevokedInfo, {'implicit': 1}),
('unknown', StatusUnknown, {'implicit': 2}),
]
class CrlId(Sequence):
_fields = [
('crl_url', IA5String, {'explicit': 0, 'optional': True}),
('crl_num', Integer, {'explicit': 1, 'optional': True}),
('crl_time', GeneralizedTime, {'explicit': 2, 'optional': True}),
]
class SingleResponseExtensionId(ObjectIdentifier):
_map = {
'1.3.6.1.5.5.7.48.1.3': 'crl',
'1.3.6.1.5.5.7.48.1.6': 'archive_cutoff',
# These are CRLEntryExtension values from
# https://tools.ietf.org/html/rfc5280
'2.5.29.21': 'crl_reason',
'2.5.29.24': 'invalidity_date',
'2.5.29.29': 'certificate_issuer',
# https://tools.ietf.org/html/rfc6962.html#page-13
'1.3.6.1.4.1.11129.2.4.5': 'signed_certificate_timestamp_list',
}
class SingleResponseExtension(Sequence):
_fields = [
('extn_id', SingleResponseExtensionId),
('critical', Boolean, {'default': False}),
('extn_value', ParsableOctetString),
]
_oid_pair = ('extn_id', 'extn_value')
_oid_specs = {
'crl': CrlId,
'archive_cutoff': GeneralizedTime,
'crl_reason': CRLReason,
'invalidity_date': GeneralizedTime,
'certificate_issuer': GeneralNames,
'signed_certificate_timestamp_list': OctetString,
}
class SingleResponseExtensions(SequenceOf):
_child_spec = SingleResponseExtension
class SingleResponse(Sequence):
_fields = [
('cert_id', CertId),
('cert_status', CertStatus),
('this_update', GeneralizedTime),
('next_update', GeneralizedTime, {'explicit': 0, 'optional': True}),
('single_extensions', SingleResponseExtensions, {'explicit': 1, 'optional': True}),
]
_processed_extensions = False
_critical_extensions = None
_crl_value = None
_archive_cutoff_value = None
_crl_reason_value = None
_invalidity_date_value = None
_certificate_issuer_value = None
def _set_extensions(self):
"""
Sets common named extensions to private attributes and creates a list
of critical extensions
"""
self._critical_extensions = set()
for extension in self['single_extensions']:
name = extension['extn_id'].native
attribute_name = '_%s_value' % name
if hasattr(self, attribute_name):
setattr(self, attribute_name, extension['extn_value'].parsed)
if extension['critical'].native:
self._critical_extensions.add(name)
self._processed_extensions = True
@property
def critical_extensions(self):
"""
Returns a set of the names (or OID if not a known extension) of the
extensions marked as critical
:return:
A set of unicode strings
"""
if not self._processed_extensions:
self._set_extensions()
return self._critical_extensions
@property
def crl_value(self):
"""
This extension is used to locate the CRL that a certificate's revocation
is contained within.
:return:
None or a CrlId object
"""
if self._processed_extensions is False:
self._set_extensions()
return self._crl_value
@property
def archive_cutoff_value(self):
"""
This extension is used to indicate the date at which an archived
(historical) certificate status entry will no longer be available.
:return:
None or a GeneralizedTime object
"""
if self._processed_extensions is False:
self._set_extensions()
return self._archive_cutoff_value
@property
def crl_reason_value(self):
"""
This extension indicates the reason that a certificate was revoked.
:return:
None or a CRLReason object
"""
if self._processed_extensions is False:
self._set_extensions()
return self._crl_reason_value
@property
def invalidity_date_value(self):
"""
This extension indicates the suspected date/time the private key was
compromised or the certificate became invalid. This would usually be
before the revocation date, which is when the CA processed the
revocation.
:return:
None or a GeneralizedTime object
"""
if self._processed_extensions is False:
self._set_extensions()
return self._invalidity_date_value
@property
def certificate_issuer_value(self):
"""
This extension indicates the issuer of the certificate in question.
:return:
None or an x509.GeneralNames object
"""
if self._processed_extensions is False:
self._set_extensions()
return self._certificate_issuer_value
class Responses(SequenceOf):
_child_spec = SingleResponse
class ResponseDataExtensionId(ObjectIdentifier):
_map = {
'1.3.6.1.5.5.7.48.1.2': 'nonce',
'1.3.6.1.5.5.7.48.1.9': 'extended_revoke',
}
class ResponseDataExtension(Sequence):
_fields = [
('extn_id', ResponseDataExtensionId),
('critical', Boolean, {'default': False}),
('extn_value', ParsableOctetString),
]
_oid_pair = ('extn_id', 'extn_value')
_oid_specs = {
'nonce': OctetString,
'extended_revoke': Null,
}
class ResponseDataExtensions(SequenceOf):
_child_spec = ResponseDataExtension
class ResponseData(Sequence):
_fields = [
('version', Version, {'explicit': 0, 'default': 'v1'}),
('responder_id', ResponderId),
('produced_at', GeneralizedTime),
('responses', Responses),
('response_extensions', ResponseDataExtensions, {'explicit': 1, 'optional': True}),
]
class BasicOCSPResponse(Sequence):
_fields = [
('tbs_response_data', ResponseData),
('signature_algorithm', SignedDigestAlgorithm),
('signature', OctetBitString),
('certs', Certificates, {'explicit': 0, 'optional': True}),
]
class ResponseBytes(Sequence):
_fields = [
('response_type', ResponseType),
('response', ParsableOctetString),
]
_oid_pair = ('response_type', 'response')
_oid_specs = {
'basic_ocsp_response': BasicOCSPResponse,
}
class OCSPResponse(Sequence):
_fields = [
('response_status', OCSPResponseStatus),
('response_bytes', ResponseBytes, {'explicit': 0, 'optional': True}),
]
_processed_extensions = False
_critical_extensions = None
_nonce_value = None
_extended_revoke_value = None
def _set_extensions(self):
"""
Sets common named extensions to private attributes and creates a list
of critical extensions
"""
self._critical_extensions = set()
for extension in self['response_bytes']['response'].parsed['tbs_response_data']['response_extensions']:
name = extension['extn_id'].native
attribute_name = '_%s_value' % name
if hasattr(self, attribute_name):
setattr(self, attribute_name, extension['extn_value'].parsed)
if extension['critical'].native:
self._critical_extensions.add(name)
self._processed_extensions = True
@property
def critical_extensions(self):
"""
Returns a set of the names (or OID if not a known extension) of the
extensions marked as critical
:return:
A set of unicode strings
"""
if not self._processed_extensions:
self._set_extensions()
return self._critical_extensions
@property
def nonce_value(self):
"""
This extension is used to prevent replay attacks on the request/response
exchange
:return:
None or an OctetString object
"""
if self._processed_extensions is False:
self._set_extensions()
return self._nonce_value
@property
def extended_revoke_value(self):
"""
This extension is used to signal that the responder will return a
"revoked" status for non-issued certificates.
:return:
None or a Null object (if present)
"""
if self._processed_extensions is False:
self._set_extensions()
return self._extended_revoke_value
@property
def basic_ocsp_response(self):
"""
A shortcut into the BasicOCSPResponse sequence
:return:
None or an asn1crypto.ocsp.BasicOCSPResponse object
"""
return self['response_bytes']['response'].parsed
@property
def response_data(self):
"""
A shortcut into the parsed, ResponseData sequence
:return:
None or an asn1crypto.ocsp.ResponseData object
"""
return self['response_bytes']['response'].parsed['tbs_response_data']