| # coding: utf-8 |
| |
| """ |
| ASN.1 type classes for certificate revocation lists (CRL). Exports the |
| following items: |
| |
| - CertificateList() |
| |
| Other type classes are defined that help compose the types listed above. |
| """ |
| |
| from __future__ import unicode_literals, division, absolute_import, print_function |
| |
| import hashlib |
| |
| from .algos import SignedDigestAlgorithm |
| from .core import ( |
| Boolean, |
| Enumerated, |
| GeneralizedTime, |
| Integer, |
| ObjectIdentifier, |
| OctetBitString, |
| ParsableOctetString, |
| Sequence, |
| SequenceOf, |
| ) |
| from .x509 import ( |
| AuthorityInfoAccessSyntax, |
| AuthorityKeyIdentifier, |
| CRLDistributionPoints, |
| DistributionPointName, |
| GeneralNames, |
| Name, |
| ReasonFlags, |
| Time, |
| ) |
| |
| |
| # The structures in this file are taken from https://tools.ietf.org/html/rfc5280 |
| |
| |
| class Version(Integer): |
| _map = { |
| 0: 'v1', |
| 1: 'v2', |
| 2: 'v3', |
| } |
| |
| |
| class IssuingDistributionPoint(Sequence): |
| _fields = [ |
| ('distribution_point', DistributionPointName, {'explicit': 0, 'optional': True}), |
| ('only_contains_user_certs', Boolean, {'implicit': 1, 'default': False}), |
| ('only_contains_ca_certs', Boolean, {'implicit': 2, 'default': False}), |
| ('only_some_reasons', ReasonFlags, {'implicit': 3, 'optional': True}), |
| ('indirect_crl', Boolean, {'implicit': 4, 'default': False}), |
| ('only_contains_attribute_certs', Boolean, {'implicit': 5, 'default': False}), |
| ] |
| |
| |
| class TBSCertListExtensionId(ObjectIdentifier): |
| _map = { |
| '2.5.29.18': 'issuer_alt_name', |
| '2.5.29.20': 'crl_number', |
| '2.5.29.27': 'delta_crl_indicator', |
| '2.5.29.28': 'issuing_distribution_point', |
| '2.5.29.35': 'authority_key_identifier', |
| '2.5.29.46': 'freshest_crl', |
| '1.3.6.1.5.5.7.1.1': 'authority_information_access', |
| } |
| |
| |
| class TBSCertListExtension(Sequence): |
| _fields = [ |
| ('extn_id', TBSCertListExtensionId), |
| ('critical', Boolean, {'default': False}), |
| ('extn_value', ParsableOctetString), |
| ] |
| |
| _oid_pair = ('extn_id', 'extn_value') |
| _oid_specs = { |
| 'issuer_alt_name': GeneralNames, |
| 'crl_number': Integer, |
| 'delta_crl_indicator': Integer, |
| 'issuing_distribution_point': IssuingDistributionPoint, |
| 'authority_key_identifier': AuthorityKeyIdentifier, |
| 'freshest_crl': CRLDistributionPoints, |
| 'authority_information_access': AuthorityInfoAccessSyntax, |
| } |
| |
| |
| class TBSCertListExtensions(SequenceOf): |
| _child_spec = TBSCertListExtension |
| |
| |
| class CRLReason(Enumerated): |
| _map = { |
| 0: 'unspecified', |
| 1: 'key_compromise', |
| 2: 'ca_compromise', |
| 3: 'affiliation_changed', |
| 4: 'superseded', |
| 5: 'cessation_of_operation', |
| 6: 'certificate_hold', |
| 8: 'remove_from_crl', |
| 9: 'privilege_withdrawn', |
| 10: 'aa_compromise', |
| } |
| |
| @property |
| def human_friendly(self): |
| """ |
| :return: |
| A unicode string with revocation description that is suitable to |
| show to end-users. Starts with a lower case letter and phrased in |
| such a way that it makes sense after the phrase "because of" or |
| "due to". |
| """ |
| |
| return { |
| 'unspecified': 'an unspecified reason', |
| 'key_compromise': 'a compromised key', |
| 'ca_compromise': 'the CA being compromised', |
| 'affiliation_changed': 'an affiliation change', |
| 'superseded': 'certificate supersession', |
| 'cessation_of_operation': 'a cessation of operation', |
| 'certificate_hold': 'a certificate hold', |
| 'remove_from_crl': 'removal from the CRL', |
| 'privilege_withdrawn': 'privilege withdrawl', |
| 'aa_compromise': 'the AA being compromised', |
| }[self.native] |
| |
| |
| class CRLEntryExtensionId(ObjectIdentifier): |
| _map = { |
| '2.5.29.21': 'crl_reason', |
| '2.5.29.23': 'hold_instruction_code', |
| '2.5.29.24': 'invalidity_date', |
| '2.5.29.29': 'certificate_issuer', |
| } |
| |
| |
| class CRLEntryExtension(Sequence): |
| _fields = [ |
| ('extn_id', CRLEntryExtensionId), |
| ('critical', Boolean, {'default': False}), |
| ('extn_value', ParsableOctetString), |
| ] |
| |
| _oid_pair = ('extn_id', 'extn_value') |
| _oid_specs = { |
| 'crl_reason': CRLReason, |
| 'hold_instruction_code': ObjectIdentifier, |
| 'invalidity_date': GeneralizedTime, |
| 'certificate_issuer': GeneralNames, |
| } |
| |
| |
| class CRLEntryExtensions(SequenceOf): |
| _child_spec = CRLEntryExtension |
| |
| |
| class RevokedCertificate(Sequence): |
| _fields = [ |
| ('user_certificate', Integer), |
| ('revocation_date', Time), |
| ('crl_entry_extensions', CRLEntryExtensions, {'optional': True}), |
| ] |
| |
| _processed_extensions = False |
| _critical_extensions = None |
| _crl_reason_value = None |
| _invalidity_date_value = None |
| _certificate_issuer_value = None |
| _issuer_name = False |
| |
| 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['crl_entry_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_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, |
| and is used in indirect CRLs. CRL entries without this extension are |
| for certificates issued from the last seen issuer. |
| |
| :return: |
| None or an x509.GeneralNames object |
| """ |
| |
| if self._processed_extensions is False: |
| self._set_extensions() |
| return self._certificate_issuer_value |
| |
| @property |
| def issuer_name(self): |
| """ |
| :return: |
| None, or an asn1crypto.x509.Name object for the issuer of the cert |
| """ |
| |
| if self._issuer_name is False: |
| self._issuer_name = None |
| if self.certificate_issuer_value: |
| for general_name in self.certificate_issuer_value: |
| if general_name.name == 'directory_name': |
| self._issuer_name = general_name.chosen |
| break |
| return self._issuer_name |
| |
| |
| class RevokedCertificates(SequenceOf): |
| _child_spec = RevokedCertificate |
| |
| |
| class TbsCertList(Sequence): |
| _fields = [ |
| ('version', Version, {'optional': True}), |
| ('signature', SignedDigestAlgorithm), |
| ('issuer', Name), |
| ('this_update', Time), |
| ('next_update', Time, {'optional': True}), |
| ('revoked_certificates', RevokedCertificates, {'optional': True}), |
| ('crl_extensions', TBSCertListExtensions, {'explicit': 0, 'optional': True}), |
| ] |
| |
| |
| class CertificateList(Sequence): |
| _fields = [ |
| ('tbs_cert_list', TbsCertList), |
| ('signature_algorithm', SignedDigestAlgorithm), |
| ('signature', OctetBitString), |
| ] |
| |
| _processed_extensions = False |
| _critical_extensions = None |
| _issuer_alt_name_value = None |
| _crl_number_value = None |
| _delta_crl_indicator_value = None |
| _issuing_distribution_point_value = None |
| _authority_key_identifier_value = None |
| _freshest_crl_value = None |
| _authority_information_access_value = None |
| _issuer_cert_urls = None |
| _delta_crl_distribution_points = None |
| _sha1 = None |
| _sha256 = 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_cert_list']['crl_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 issuer_alt_name_value(self): |
| """ |
| This extension allows associating one or more alternative names with |
| the issuer of the CRL. |
| |
| :return: |
| None or an x509.GeneralNames object |
| """ |
| |
| if self._processed_extensions is False: |
| self._set_extensions() |
| return self._issuer_alt_name_value |
| |
| @property |
| def crl_number_value(self): |
| """ |
| This extension adds a monotonically increasing number to the CRL and is |
| used to distinguish different versions of the CRL. |
| |
| :return: |
| None or an Integer object |
| """ |
| |
| if self._processed_extensions is False: |
| self._set_extensions() |
| return self._crl_number_value |
| |
| @property |
| def delta_crl_indicator_value(self): |
| """ |
| This extension indicates a CRL is a delta CRL, and contains the CRL |
| number of the base CRL that it is a delta from. |
| |
| :return: |
| None or an Integer object |
| """ |
| |
| if self._processed_extensions is False: |
| self._set_extensions() |
| return self._delta_crl_indicator_value |
| |
| @property |
| def issuing_distribution_point_value(self): |
| """ |
| This extension includes information about what types of revocations |
| and certificates are part of the CRL. |
| |
| :return: |
| None or an IssuingDistributionPoint object |
| """ |
| |
| if self._processed_extensions is False: |
| self._set_extensions() |
| return self._issuing_distribution_point_value |
| |
| @property |
| def authority_key_identifier_value(self): |
| """ |
| This extension helps in identifying the public key with which to |
| validate the authenticity of the CRL. |
| |
| :return: |
| None or an AuthorityKeyIdentifier object |
| """ |
| |
| if self._processed_extensions is False: |
| self._set_extensions() |
| return self._authority_key_identifier_value |
| |
| @property |
| def freshest_crl_value(self): |
| """ |
| This extension is used in complete CRLs to indicate where a delta CRL |
| may be located. |
| |
| :return: |
| None or a CRLDistributionPoints object |
| """ |
| |
| if self._processed_extensions is False: |
| self._set_extensions() |
| return self._freshest_crl_value |
| |
| @property |
| def authority_information_access_value(self): |
| """ |
| This extension is used to provide a URL with which to download the |
| certificate used to sign this CRL. |
| |
| :return: |
| None or an AuthorityInfoAccessSyntax object |
| """ |
| |
| if self._processed_extensions is False: |
| self._set_extensions() |
| return self._authority_information_access_value |
| |
| @property |
| def issuer(self): |
| """ |
| :return: |
| An asn1crypto.x509.Name object for the issuer of the CRL |
| """ |
| |
| return self['tbs_cert_list']['issuer'] |
| |
| @property |
| def authority_key_identifier(self): |
| """ |
| :return: |
| None or a byte string of the key_identifier from the authority key |
| identifier extension |
| """ |
| |
| if not self.authority_key_identifier_value: |
| return None |
| |
| return self.authority_key_identifier_value['key_identifier'].native |
| |
| @property |
| def issuer_cert_urls(self): |
| """ |
| :return: |
| A list of unicode strings that are URLs that should contain either |
| an individual DER-encoded X.509 certificate, or a DER-encoded CMS |
| message containing multiple certificates |
| """ |
| |
| if self._issuer_cert_urls is None: |
| self._issuer_cert_urls = [] |
| if self.authority_information_access_value: |
| for entry in self.authority_information_access_value: |
| if entry['access_method'].native == 'ca_issuers': |
| location = entry['access_location'] |
| if location.name != 'uniform_resource_identifier': |
| continue |
| url = location.native |
| if url.lower()[0:7] == 'http://': |
| self._issuer_cert_urls.append(url) |
| return self._issuer_cert_urls |
| |
| @property |
| def delta_crl_distribution_points(self): |
| """ |
| Returns delta CRL URLs - only applies to complete CRLs |
| |
| :return: |
| A list of zero or more DistributionPoint objects |
| """ |
| |
| if self._delta_crl_distribution_points is None: |
| self._delta_crl_distribution_points = [] |
| |
| if self.freshest_crl_value is not None: |
| for distribution_point in self.freshest_crl_value: |
| distribution_point_name = distribution_point['distribution_point'] |
| # RFC 5280 indicates conforming CA should not use the relative form |
| if distribution_point_name.name == 'name_relative_to_crl_issuer': |
| continue |
| # This library is currently only concerned with HTTP-based CRLs |
| for general_name in distribution_point_name.chosen: |
| if general_name.name == 'uniform_resource_identifier': |
| self._delta_crl_distribution_points.append(distribution_point) |
| |
| return self._delta_crl_distribution_points |
| |
| @property |
| def signature(self): |
| """ |
| :return: |
| A byte string of the signature |
| """ |
| |
| return self['signature'].native |
| |
| @property |
| def sha1(self): |
| """ |
| :return: |
| The SHA1 hash of the DER-encoded bytes of this certificate list |
| """ |
| |
| if self._sha1 is None: |
| self._sha1 = hashlib.sha1(self.dump()).digest() |
| return self._sha1 |
| |
| @property |
| def sha256(self): |
| """ |
| :return: |
| The SHA-256 hash of the DER-encoded bytes of this certificate list |
| """ |
| |
| if self._sha256 is None: |
| self._sha256 = hashlib.sha256(self.dump()).digest() |
| return self._sha256 |
