wbond | e91513e | 2015-06-03 14:52:18 -0400 | [diff] [blame] | 1 | # coding: utf-8 |
wbond | ea25fc2 | 2015-06-19 15:07:04 -0400 | [diff] [blame] | 2 | |
| 3 | """ |
| 4 | ASN.1 type classes for certificate revocation lists (CRL). Exports the |
| 5 | following items: |
| 6 | |
| 7 | - CertificateList() |
| 8 | |
| 9 | Other type classes are defined that help compose the types listed above. |
| 10 | """ |
| 11 | |
wbond | 6b66ab5 | 2015-06-21 10:26:45 -0400 | [diff] [blame] | 12 | from __future__ import unicode_literals, division, absolute_import, print_function |
wbond | e91513e | 2015-06-03 14:52:18 -0400 | [diff] [blame] | 13 | |
| 14 | from .algos import SignedDigestAlgorithm |
| 15 | from .core import ( |
| 16 | Boolean, |
| 17 | Enumerated, |
| 18 | GeneralizedTime, |
| 19 | Integer, |
| 20 | ObjectIdentifier, |
| 21 | OctetBitString, |
| 22 | OctetString, |
| 23 | Sequence, |
| 24 | SequenceOf, |
| 25 | ) |
| 26 | from .x509 import ( |
wbond | a0d4548 | 2015-07-13 22:10:20 -0400 | [diff] [blame] | 27 | AuthorityInfoAccessSyntax, |
wbond | e91513e | 2015-06-03 14:52:18 -0400 | [diff] [blame] | 28 | AuthorityKeyIdentifier, |
| 29 | CRLDistributionPoints, |
| 30 | DistributionPointName, |
wbond | e91513e | 2015-06-03 14:52:18 -0400 | [diff] [blame] | 31 | GeneralNames, |
| 32 | Name, |
| 33 | ReasonFlags, |
| 34 | Time, |
| 35 | ) |
| 36 | |
| 37 | |
| 38 | |
| 39 | # The structures in this file are taken from https://tools.ietf.org/html/rfc5280 |
| 40 | |
| 41 | |
| 42 | class Version(Integer): |
| 43 | _map = { |
| 44 | 0: 'v1', |
| 45 | 1: 'v2', |
| 46 | 2: 'v3', |
| 47 | } |
| 48 | |
| 49 | |
| 50 | class IssuingDistributionPoint(Sequence): |
| 51 | _fields = [ |
| 52 | ('distribution_point', DistributionPointName, {'tag_type': 'explicit', 'tag': 0, 'optional': True}), |
| 53 | ('only_contains_user_certs', Boolean, {'tag_type': 'implicit', 'tag': 1, 'default': False}), |
| 54 | ('only_contains_ca_certs', Boolean, {'tag_type': 'implicit', 'tag': 2, 'default': False}), |
| 55 | ('only_some_reasons', ReasonFlags, {'tag_type': 'implicit', 'tag': 3, 'optional': True}), |
| 56 | ('indirect_crl', Boolean, {'tag_type': 'implicit', 'tag': 4, 'default': False}), |
| 57 | ('only_contains_attribute_certs', Boolean, {'tag_type': 'implicit', 'tag': 5, 'default': False}), |
| 58 | ] |
| 59 | |
| 60 | |
wbond | e91513e | 2015-06-03 14:52:18 -0400 | [diff] [blame] | 61 | class TBSCertListExtensionId(ObjectIdentifier): |
| 62 | _map = { |
| 63 | '2.5.29.18': 'issuer_alt_name', |
| 64 | '2.5.29.20': 'crl_number', |
| 65 | '2.5.29.27': 'delta_crl_indicator', |
| 66 | '2.5.29.28': 'issuing_distribution_point', |
| 67 | '2.5.29.35': 'authority_key_identifier', |
| 68 | '2.5.29.46': 'freshest_crl', |
| 69 | '1.3.6.1.5.5.7.1.1': 'authority_information_access', |
| 70 | } |
| 71 | |
| 72 | |
| 73 | class TBSCertListExtension(Sequence): |
| 74 | _fields = [ |
| 75 | ('extn_id', TBSCertListExtensionId), |
| 76 | ('critical', Boolean, {'default': False}), |
| 77 | ('extn_value', OctetString), |
| 78 | ] |
| 79 | |
| 80 | _oid_pair = ('extn_id', 'extn_value') |
| 81 | _oid_specs = { |
| 82 | 'issuer_alt_name': GeneralNames, |
| 83 | 'crl_number': Integer, |
| 84 | 'delta_crl_indicator': Integer, |
| 85 | 'issuing_distribution_point': IssuingDistributionPoint, |
| 86 | 'authority_key_identifier': AuthorityKeyIdentifier, |
| 87 | 'freshest_crl': CRLDistributionPoints, |
| 88 | 'authority_information_access': AuthorityInfoAccessSyntax, |
| 89 | } |
| 90 | |
| 91 | |
| 92 | class TBSCertListExtensions(SequenceOf): |
| 93 | _child_spec = TBSCertListExtension |
| 94 | |
| 95 | |
| 96 | class CRLReason(Enumerated): |
| 97 | _map = { |
| 98 | 0: 'unspecified', |
| 99 | 1: 'key_compromise', |
| 100 | 2: 'ca_compromise', |
| 101 | 3: 'affiliation_changed', |
| 102 | 4: 'superseded', |
| 103 | 5: 'cessation_of_operation', |
| 104 | 6: 'certificate_hold', |
| 105 | 8: 'remove_from_crl', |
| 106 | 9: 'privilege_withdrawn', |
| 107 | 10: 'aa_compromise', |
| 108 | } |
| 109 | |
wbond | 2f1eb26 | 2015-07-20 08:52:34 -0400 | [diff] [blame] | 110 | @property |
| 111 | def human_friendly(self): |
| 112 | """ |
| 113 | :return: |
| 114 | A unicode string with revocation description that is suitable to |
| 115 | show to end-users. Starts with a lower case letter and phrased in |
| 116 | such a way that it makes sense after the phrase "because of" or |
| 117 | "due to". |
| 118 | """ |
| 119 | |
| 120 | return { |
| 121 | 'unspecified': 'an unspecified reason', |
| 122 | 'key_compromise': 'a compromised key', |
| 123 | 'ca_compromise': 'the CA being compromised', |
| 124 | 'affiliation_changed': 'an affiliation change', |
| 125 | 'superseded': 'certificate supersession', |
| 126 | 'cessation_of_operation': 'a cessation of operation', |
| 127 | 'certificate_hold': 'a certificate hold', |
| 128 | 'remove_from_crl': 'removal from the CRL', |
| 129 | 'privilege_withdrawn': 'privilege withdrawl', |
| 130 | 'aa_compromise': 'the AA being compromised', |
| 131 | }[self.native] |
| 132 | |
wbond | e91513e | 2015-06-03 14:52:18 -0400 | [diff] [blame] | 133 | |
| 134 | class CRLEntryExtensionId(ObjectIdentifier): |
| 135 | _map = { |
| 136 | '2.5.29.21': 'crl_reason', |
wbond | 0b7ffe7 | 2015-07-27 15:57:44 -0400 | [diff] [blame^] | 137 | '2.5.29.23': 'hold_instruction_code', |
wbond | e91513e | 2015-06-03 14:52:18 -0400 | [diff] [blame] | 138 | '2.5.29.24': 'invalidity_date', |
| 139 | '2.5.29.29': 'certificate_issuer', |
| 140 | } |
| 141 | |
| 142 | |
| 143 | class CRLEntryExtension(Sequence): |
| 144 | _fields = [ |
| 145 | ('extn_id', CRLEntryExtensionId), |
| 146 | ('critical', Boolean, {'default': False}), |
| 147 | ('extn_value', OctetString), |
| 148 | ] |
| 149 | |
| 150 | _oid_pair = ('extn_id', 'extn_value') |
| 151 | _oid_specs = { |
| 152 | 'crl_reason': CRLReason, |
wbond | 0b7ffe7 | 2015-07-27 15:57:44 -0400 | [diff] [blame^] | 153 | 'hold_instruction_code': ObjectIdentifier, |
wbond | e91513e | 2015-06-03 14:52:18 -0400 | [diff] [blame] | 154 | 'invalidity_date': GeneralizedTime, |
| 155 | 'certificate_issuer': GeneralNames, |
| 156 | } |
| 157 | |
| 158 | |
| 159 | class CRLEntryExtensions(SequenceOf): |
| 160 | _child_spec = CRLEntryExtension |
| 161 | |
| 162 | |
| 163 | class RevokedCertificate(Sequence): |
| 164 | _fields = [ |
| 165 | ('user_certificate', Integer), |
| 166 | ('revocation_date', Time), |
| 167 | ('crl_entry_extensions', CRLEntryExtensions, {'optional': True}), |
| 168 | ] |
| 169 | |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 170 | _processed_extensions = False |
| 171 | _critical_extensions = None |
| 172 | _crl_reason_value = None |
| 173 | _invalidity_date_value = None |
| 174 | _certificate_issuer_value = None |
wbond | 5fb733f | 2015-07-21 14:57:59 -0400 | [diff] [blame] | 175 | _issuer_name = False |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 176 | |
| 177 | def _set_extensions(self): |
| 178 | """ |
| 179 | Sets common named extensions to private attributes and creates a list |
| 180 | of critical extensions |
| 181 | """ |
| 182 | |
wbond | 2fde645 | 2015-07-23 10:54:13 -0400 | [diff] [blame] | 183 | self._critical_extensions = set() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 184 | |
| 185 | for extension in self['crl_entry_extensions']: |
| 186 | name = extension['extn_id'].native |
| 187 | attribute_name = '_%s_value' % name |
| 188 | if hasattr(self, attribute_name): |
| 189 | setattr(self, attribute_name, extension['extn_value'].parsed) |
| 190 | if extension['critical'].native: |
wbond | 2fde645 | 2015-07-23 10:54:13 -0400 | [diff] [blame] | 191 | self._critical_extensions.add(name) |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 192 | |
| 193 | self._processed_extensions = True |
| 194 | |
| 195 | @property |
| 196 | def critical_extensions(self): |
| 197 | """ |
wbond | 2fde645 | 2015-07-23 10:54:13 -0400 | [diff] [blame] | 198 | Returns a set of the names (or OID if not a known extension) of the |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 199 | extensions marked as critical |
| 200 | |
| 201 | :return: |
wbond | 2fde645 | 2015-07-23 10:54:13 -0400 | [diff] [blame] | 202 | A set of unicode strings |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 203 | """ |
| 204 | |
| 205 | if not self._processed_extensions: |
| 206 | self._set_extensions() |
| 207 | return self._critical_extensions |
| 208 | |
| 209 | @property |
| 210 | def crl_reason_value(self): |
| 211 | """ |
| 212 | This extension indicates the reason that a certificate was revoked. |
| 213 | |
| 214 | :return: |
| 215 | None or a CRLReason object |
| 216 | """ |
| 217 | |
| 218 | if self._processed_extensions is False: |
wbond | ad218f9 | 2015-07-20 10:43:16 -0400 | [diff] [blame] | 219 | self._set_extensions() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 220 | return self._crl_reason_value |
| 221 | |
| 222 | @property |
| 223 | def invalidity_date_value(self): |
| 224 | """ |
| 225 | This extension indicates the suspected date/time the private key was |
| 226 | compromised or the certificate became invalid. This would usually be |
| 227 | before the revocation date, which is when the CA processed the |
| 228 | revocation. |
| 229 | |
| 230 | :return: |
| 231 | None or a GeneralizedTime object |
| 232 | """ |
| 233 | |
| 234 | if self._processed_extensions is False: |
wbond | ad218f9 | 2015-07-20 10:43:16 -0400 | [diff] [blame] | 235 | self._set_extensions() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 236 | return self._invalidity_date_value |
| 237 | |
| 238 | @property |
| 239 | def certificate_issuer_value(self): |
| 240 | """ |
| 241 | This extension indicates the issuer of the certificate in question, |
| 242 | and is used in indirect CRLs. CRL entries without this extension are |
| 243 | for certificates issued from the last seen issuer. |
| 244 | |
| 245 | :return: |
| 246 | None or an x509.GeneralNames object |
| 247 | """ |
| 248 | |
| 249 | if self._processed_extensions is False: |
wbond | ad218f9 | 2015-07-20 10:43:16 -0400 | [diff] [blame] | 250 | self._set_extensions() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 251 | return self._certificate_issuer_value |
| 252 | |
wbond | 5fb733f | 2015-07-21 14:57:59 -0400 | [diff] [blame] | 253 | @property |
| 254 | def issuer_name(self): |
| 255 | """ |
| 256 | :return: |
| 257 | None, or an asn1crypto.x509.Name object for the issuer of the cert |
| 258 | """ |
| 259 | |
| 260 | if self._issuer_name is False: |
| 261 | self._issuer_name = None |
| 262 | if self.certificate_issuer_value: |
| 263 | for general_name in self.certificate_issuer_value: |
| 264 | if general_name.name == 'directory_name': |
| 265 | self._issuer_name = general_name.chosen |
| 266 | break |
| 267 | return self._issuer_name |
| 268 | |
wbond | e91513e | 2015-06-03 14:52:18 -0400 | [diff] [blame] | 269 | |
| 270 | class RevokedCertificates(SequenceOf): |
| 271 | _child_spec = RevokedCertificate |
| 272 | |
| 273 | |
| 274 | class TbsCertList(Sequence): |
| 275 | _fields = [ |
| 276 | ('version', Version, {'optional': True}), |
| 277 | ('signature', SignedDigestAlgorithm), |
| 278 | ('issuer', Name), |
| 279 | ('this_update', Time), |
| 280 | ('next_update', Time), |
| 281 | ('revoked_certificates', RevokedCertificates, {'optional': True}), |
| 282 | ('crl_extensions', TBSCertListExtensions, {'tag_type': 'explicit', 'tag': 0, 'optional': True}), |
| 283 | ] |
| 284 | |
| 285 | |
| 286 | class CertificateList(Sequence): |
| 287 | _fields = [ |
| 288 | ('tbs_cert_list', TbsCertList), |
wbond | 4a2627f | 2015-07-21 14:56:48 -0400 | [diff] [blame] | 289 | ('signature_algorithm', SignedDigestAlgorithm), |
wbond | e91513e | 2015-06-03 14:52:18 -0400 | [diff] [blame] | 290 | ('signature', OctetBitString), |
| 291 | ] |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 292 | |
| 293 | _processed_extensions = False |
| 294 | _critical_extensions = None |
wbond | a613f81 | 2015-07-20 10:13:47 -0400 | [diff] [blame] | 295 | _issuer_alt_name_value = None |
| 296 | _crl_number_value = None |
| 297 | _delta_crl_indicator_value = None |
| 298 | _issuing_distribution_point_value = None |
| 299 | _authority_key_identifier_value = None |
| 300 | _freshest_crl_value = None |
| 301 | _authority_information_access_value = None |
wbond | 5fb733f | 2015-07-21 14:57:59 -0400 | [diff] [blame] | 302 | _issuer_cert_urls = None |
| 303 | _delta_crl_distribution_points = None |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 304 | |
| 305 | def _set_extensions(self): |
| 306 | """ |
| 307 | Sets common named extensions to private attributes and creates a list |
| 308 | of critical extensions |
| 309 | """ |
| 310 | |
wbond | 2fde645 | 2015-07-23 10:54:13 -0400 | [diff] [blame] | 311 | self._critical_extensions = set() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 312 | |
| 313 | for extension in self['tbs_cert_list']['crl_extensions']: |
| 314 | name = extension['extn_id'].native |
| 315 | attribute_name = '_%s_value' % name |
| 316 | if hasattr(self, attribute_name): |
| 317 | setattr(self, attribute_name, extension['extn_value'].parsed) |
| 318 | if extension['critical'].native: |
wbond | 2fde645 | 2015-07-23 10:54:13 -0400 | [diff] [blame] | 319 | self._critical_extensions.add(name) |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 320 | |
| 321 | self._processed_extensions = True |
| 322 | |
| 323 | @property |
| 324 | def critical_extensions(self): |
| 325 | """ |
wbond | 2fde645 | 2015-07-23 10:54:13 -0400 | [diff] [blame] | 326 | Returns a set of the names (or OID if not a known extension) of the |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 327 | extensions marked as critical |
| 328 | |
| 329 | :return: |
wbond | 2fde645 | 2015-07-23 10:54:13 -0400 | [diff] [blame] | 330 | A set of unicode strings |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 331 | """ |
| 332 | |
| 333 | if not self._processed_extensions: |
| 334 | self._set_extensions() |
| 335 | return self._critical_extensions |
| 336 | |
| 337 | @property |
| 338 | def issuer_alt_name_value(self): |
| 339 | """ |
| 340 | This extension allows associating one or more alternative names with |
| 341 | the issuer of the CRL. |
| 342 | |
| 343 | :return: |
| 344 | None or an x509.GeneralNames object |
| 345 | """ |
| 346 | |
| 347 | if self._processed_extensions is False: |
wbond | ad218f9 | 2015-07-20 10:43:16 -0400 | [diff] [blame] | 348 | self._set_extensions() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 349 | return self._issuer_alt_name_value |
| 350 | |
| 351 | @property |
| 352 | def crl_number_value(self): |
| 353 | """ |
| 354 | This extension adds a monotonically increasing number to the CRL and is |
| 355 | used to distinguish different versions of the CRL. |
| 356 | |
| 357 | :return: |
| 358 | None or an Integer object |
| 359 | """ |
| 360 | |
| 361 | if self._processed_extensions is False: |
wbond | ad218f9 | 2015-07-20 10:43:16 -0400 | [diff] [blame] | 362 | self._set_extensions() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 363 | return self._crl_number_value |
| 364 | |
| 365 | @property |
| 366 | def delta_crl_indicator_value(self): |
| 367 | """ |
| 368 | This extension indicates a CRL is a delta CRL, and contains the CRL |
| 369 | number of the base CRL that it is a delta from. |
| 370 | |
| 371 | :return: |
| 372 | None or an Integer object |
| 373 | """ |
| 374 | |
| 375 | if self._processed_extensions is False: |
wbond | ad218f9 | 2015-07-20 10:43:16 -0400 | [diff] [blame] | 376 | self._set_extensions() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 377 | return self._delta_crl_indicator_value |
| 378 | |
| 379 | @property |
| 380 | def issuing_distribution_point_value(self): |
| 381 | """ |
| 382 | This extension includes information about what types of revocations |
| 383 | and certificates are part of the CRL. |
| 384 | |
| 385 | :return: |
| 386 | None or an IssuingDistributionPoint object |
| 387 | """ |
| 388 | |
| 389 | if self._processed_extensions is False: |
wbond | ad218f9 | 2015-07-20 10:43:16 -0400 | [diff] [blame] | 390 | self._set_extensions() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 391 | return self._issuing_distribution_point_value |
| 392 | |
| 393 | @property |
| 394 | def authority_key_identifier_value(self): |
| 395 | """ |
| 396 | This extension helps in identifying the public key with which to |
| 397 | validate the authenticity of the CRL. |
| 398 | |
| 399 | :return: |
| 400 | None or an AuthorityKeyIdentifier object |
| 401 | """ |
| 402 | |
| 403 | if self._processed_extensions is False: |
wbond | ad218f9 | 2015-07-20 10:43:16 -0400 | [diff] [blame] | 404 | self._set_extensions() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 405 | return self._authority_key_identifier_value |
| 406 | |
| 407 | @property |
| 408 | def freshest_crl_value(self): |
| 409 | """ |
| 410 | This extension is used in complete CRLs to indicate where a delta CRL |
| 411 | may be located. |
| 412 | |
| 413 | :return: |
| 414 | None or a CRLDistributionPoints object |
| 415 | """ |
| 416 | |
| 417 | if self._processed_extensions is False: |
wbond | ad218f9 | 2015-07-20 10:43:16 -0400 | [diff] [blame] | 418 | self._set_extensions() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 419 | return self._freshest_crl_value |
| 420 | |
| 421 | @property |
| 422 | def authority_information_access_value(self): |
| 423 | """ |
| 424 | This extension is used to provide a URL with which to download the |
| 425 | certificate used to sign this CRL. |
| 426 | |
| 427 | :return: |
| 428 | None or an AuthorityInfoAccessSyntax object |
| 429 | """ |
| 430 | |
| 431 | if self._processed_extensions is False: |
wbond | ad218f9 | 2015-07-20 10:43:16 -0400 | [diff] [blame] | 432 | self._set_extensions() |
wbond | 598c228 | 2015-07-20 08:54:22 -0400 | [diff] [blame] | 433 | return self._authority_information_access_value |
wbond | 5fb733f | 2015-07-21 14:57:59 -0400 | [diff] [blame] | 434 | |
| 435 | @property |
wbond | 7a5c015 | 2015-07-24 08:37:53 -0400 | [diff] [blame] | 436 | def issuer(self): |
| 437 | """ |
| 438 | :return: |
| 439 | An asn1crypto.x509.Name object for the issuer of the CRL |
| 440 | """ |
| 441 | |
| 442 | return self['tbs_cert_list']['issuer'] |
| 443 | |
| 444 | @property |
wbond | 5fb733f | 2015-07-21 14:57:59 -0400 | [diff] [blame] | 445 | def authority_key_identifier(self): |
| 446 | """ |
| 447 | :return: |
| 448 | None or a byte string of the key_identifier from the authority key |
| 449 | identifier extension |
| 450 | """ |
| 451 | |
| 452 | if not self.authority_key_identifier_value: |
| 453 | return None |
| 454 | |
| 455 | return self.authority_key_identifier_value['key_identifier'].native |
| 456 | |
| 457 | @property |
| 458 | def issuer_cert_urls(self): |
| 459 | """ |
| 460 | :return: |
| 461 | A list of unicode strings that are URLs that should contain either |
| 462 | an individual DER-encoded X509 certificate, or a DER-encoded CMS |
| 463 | message containing multiple certificates |
| 464 | """ |
| 465 | |
| 466 | if self._issuer_cert_urls is None: |
| 467 | self._issuer_cert_urls = [] |
| 468 | if self.authority_information_access_value: |
| 469 | for entry in self.authority_information_access_value: |
| 470 | if entry['access_method'].native == 'ca_issuers': |
| 471 | location = entry['access_location'] |
| 472 | if location.name != 'uniform_resource_identifier': |
| 473 | continue |
| 474 | url = location.native |
| 475 | if url.lower()[0:7] == 'http://': |
| 476 | self._issuer_cert_urls.append(url) |
| 477 | return self._issuer_cert_urls |
| 478 | |
| 479 | @property |
| 480 | def delta_crl_distribution_points(self): |
| 481 | """ |
| 482 | Returns delta CRL URLs - only applies to complete CRLs |
| 483 | |
| 484 | :return: |
| 485 | A list of zero or more DistributionPoint objects |
| 486 | """ |
| 487 | |
| 488 | if self._delta_crl_distribution_points is None: |
| 489 | self._delta_crl_distribution_points = [] |
| 490 | |
| 491 | if self.freshest_crl_value is not None: |
| 492 | for distribution_point in self.freshest_crl_value: |
| 493 | distribution_point_name = distribution_point['distribution_point'] |
| 494 | # RFC5280 indicates conforming CA should not use the relative form |
| 495 | if distribution_point_name.name == 'name_relative_to_crl_issuer': |
| 496 | continue |
| 497 | # This library is currently only concerned with HTTP-based CRLs |
| 498 | for general_name in distribution_point_name.chosen: |
| 499 | if general_name.name == 'uniform_resource_identifier': |
| 500 | self._delta_crl_distribution_points.append(distribution_point) |
| 501 | |
| 502 | return self._delta_crl_distribution_points |