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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import absolute_import, division, print_function
import abc
import datetime
import os
from enum import Enum
import six
from cryptography import utils
from cryptography.hazmat.backends import _get_backend
from cryptography.hazmat.primitives.asymmetric import (
dsa,
ec,
ed25519,
ed448,
rsa,
)
from cryptography.x509.extensions import Extension, ExtensionType
from cryptography.x509.name import Name
from cryptography.x509.oid import ObjectIdentifier
_EARLIEST_UTC_TIME = datetime.datetime(1950, 1, 1)
class AttributeNotFound(Exception):
def __init__(self, msg, oid):
super(AttributeNotFound, self).__init__(msg)
self.oid = oid
def _reject_duplicate_extension(extension, extensions):
# This is quadratic in the number of extensions
for e in extensions:
if e.oid == extension.oid:
raise ValueError("This extension has already been set.")
def _reject_duplicate_attribute(oid, attributes):
# This is quadratic in the number of attributes
for attr_oid, _ in attributes:
if attr_oid == oid:
raise ValueError("This attribute has already been set.")
def _convert_to_naive_utc_time(time):
"""Normalizes a datetime to a naive datetime in UTC.
time -- datetime to normalize. Assumed to be in UTC if not timezone
aware.
"""
if time.tzinfo is not None:
offset = time.utcoffset()
offset = offset if offset else datetime.timedelta()
return time.replace(tzinfo=None) - offset
else:
return time
class Version(Enum):
v1 = 0
v3 = 2
def load_pem_x509_certificate(data, backend=None):
backend = _get_backend(backend)
return backend.load_pem_x509_certificate(data)
def load_der_x509_certificate(data, backend=None):
backend = _get_backend(backend)
return backend.load_der_x509_certificate(data)
def load_pem_x509_csr(data, backend=None):
backend = _get_backend(backend)
return backend.load_pem_x509_csr(data)
def load_der_x509_csr(data, backend=None):
backend = _get_backend(backend)
return backend.load_der_x509_csr(data)
def load_pem_x509_crl(data, backend=None):
backend = _get_backend(backend)
return backend.load_pem_x509_crl(data)
def load_der_x509_crl(data, backend=None):
backend = _get_backend(backend)
return backend.load_der_x509_crl(data)
class InvalidVersion(Exception):
def __init__(self, msg, parsed_version):
super(InvalidVersion, self).__init__(msg)
self.parsed_version = parsed_version
@six.add_metaclass(abc.ABCMeta)
class Certificate(object):
@abc.abstractmethod
def fingerprint(self, algorithm):
"""
Returns bytes using digest passed.
"""
@abc.abstractproperty
def serial_number(self):
"""
Returns certificate serial number
"""
@abc.abstractproperty
def version(self):
"""
Returns the certificate version
"""
@abc.abstractmethod
def public_key(self):
"""
Returns the public key
"""
@abc.abstractproperty
def not_valid_before(self):
"""
Not before time (represented as UTC datetime)
"""
@abc.abstractproperty
def not_valid_after(self):
"""
Not after time (represented as UTC datetime)
"""
@abc.abstractproperty
def issuer(self):
"""
Returns the issuer name object.
"""
@abc.abstractproperty
def subject(self):
"""
Returns the subject name object.
"""
@abc.abstractproperty
def signature_hash_algorithm(self):
"""
Returns a HashAlgorithm corresponding to the type of the digest signed
in the certificate.
"""
@abc.abstractproperty
def signature_algorithm_oid(self):
"""
Returns the ObjectIdentifier of the signature algorithm.
"""
@abc.abstractproperty
def extensions(self):
"""
Returns an Extensions object.
"""
@abc.abstractproperty
def signature(self):
"""
Returns the signature bytes.
"""
@abc.abstractproperty
def tbs_certificate_bytes(self):
"""
Returns the tbsCertificate payload bytes as defined in RFC 5280.
"""
@abc.abstractmethod
def __eq__(self, other):
"""
Checks equality.
"""
@abc.abstractmethod
def __ne__(self, other):
"""
Checks not equal.
"""
@abc.abstractmethod
def __hash__(self):
"""
Computes a hash.
"""
@abc.abstractmethod
def public_bytes(self, encoding):
"""
Serializes the certificate to PEM or DER format.
"""
@six.add_metaclass(abc.ABCMeta)
class CertificateRevocationList(object):
@abc.abstractmethod
def public_bytes(self, encoding):
"""
Serializes the CRL to PEM or DER format.
"""
@abc.abstractmethod
def fingerprint(self, algorithm):
"""
Returns bytes using digest passed.
"""
@abc.abstractmethod
def get_revoked_certificate_by_serial_number(self, serial_number):
"""
Returns an instance of RevokedCertificate or None if the serial_number
is not in the CRL.
"""
@abc.abstractproperty
def signature_hash_algorithm(self):
"""
Returns a HashAlgorithm corresponding to the type of the digest signed
in the certificate.
"""
@abc.abstractproperty
def signature_algorithm_oid(self):
"""
Returns the ObjectIdentifier of the signature algorithm.
"""
@abc.abstractproperty
def issuer(self):
"""
Returns the X509Name with the issuer of this CRL.
"""
@abc.abstractproperty
def next_update(self):
"""
Returns the date of next update for this CRL.
"""
@abc.abstractproperty
def last_update(self):
"""
Returns the date of last update for this CRL.
"""
@abc.abstractproperty
def extensions(self):
"""
Returns an Extensions object containing a list of CRL extensions.
"""
@abc.abstractproperty
def signature(self):
"""
Returns the signature bytes.
"""
@abc.abstractproperty
def tbs_certlist_bytes(self):
"""
Returns the tbsCertList payload bytes as defined in RFC 5280.
"""
@abc.abstractmethod
def __eq__(self, other):
"""
Checks equality.
"""
@abc.abstractmethod
def __ne__(self, other):
"""
Checks not equal.
"""
@abc.abstractmethod
def __len__(self):
"""
Number of revoked certificates in the CRL.
"""
@abc.abstractmethod
def __getitem__(self, idx):
"""
Returns a revoked certificate (or slice of revoked certificates).
"""
@abc.abstractmethod
def __iter__(self):
"""
Iterator over the revoked certificates
"""
@abc.abstractmethod
def is_signature_valid(self, public_key):
"""
Verifies signature of revocation list against given public key.
"""
@six.add_metaclass(abc.ABCMeta)
class CertificateSigningRequest(object):
@abc.abstractmethod
def __eq__(self, other):
"""
Checks equality.
"""
@abc.abstractmethod
def __ne__(self, other):
"""
Checks not equal.
"""
@abc.abstractmethod
def __hash__(self):
"""
Computes a hash.
"""
@abc.abstractmethod
def public_key(self):
"""
Returns the public key
"""
@abc.abstractproperty
def subject(self):
"""
Returns the subject name object.
"""
@abc.abstractproperty
def signature_hash_algorithm(self):
"""
Returns a HashAlgorithm corresponding to the type of the digest signed
in the certificate.
"""
@abc.abstractproperty
def signature_algorithm_oid(self):
"""
Returns the ObjectIdentifier of the signature algorithm.
"""
@abc.abstractproperty
def extensions(self):
"""
Returns the extensions in the signing request.
"""
@abc.abstractmethod
def public_bytes(self, encoding):
"""
Encodes the request to PEM or DER format.
"""
@abc.abstractproperty
def signature(self):
"""
Returns the signature bytes.
"""
@abc.abstractproperty
def tbs_certrequest_bytes(self):
"""
Returns the PKCS#10 CertificationRequestInfo bytes as defined in RFC
2986.
"""
@abc.abstractproperty
def is_signature_valid(self):
"""
Verifies signature of signing request.
"""
@abc.abstractproperty
def get_attribute_for_oid(self):
"""
Get the attribute value for a given OID.
"""
@six.add_metaclass(abc.ABCMeta)
class RevokedCertificate(object):
@abc.abstractproperty
def serial_number(self):
"""
Returns the serial number of the revoked certificate.
"""
@abc.abstractproperty
def revocation_date(self):
"""
Returns the date of when this certificate was revoked.
"""
@abc.abstractproperty
def extensions(self):
"""
Returns an Extensions object containing a list of Revoked extensions.
"""
class CertificateSigningRequestBuilder(object):
def __init__(self, subject_name=None, extensions=[], attributes=[]):
"""
Creates an empty X.509 certificate request (v1).
"""
self._subject_name = subject_name
self._extensions = extensions
self._attributes = attributes
def subject_name(self, name):
"""
Sets the certificate requestor's distinguished name.
"""
if not isinstance(name, Name):
raise TypeError("Expecting x509.Name object.")
if self._subject_name is not None:
raise ValueError("The subject name may only be set once.")
return CertificateSigningRequestBuilder(
name, self._extensions, self._attributes
)
def add_extension(self, extension, critical):
"""
Adds an X.509 extension to the certificate request.
"""
if not isinstance(extension, ExtensionType):
raise TypeError("extension must be an ExtensionType")
extension = Extension(extension.oid, critical, extension)
_reject_duplicate_extension(extension, self._extensions)
return CertificateSigningRequestBuilder(
self._subject_name,
self._extensions + [extension],
self._attributes,
)
def add_attribute(self, oid, value):
"""
Adds an X.509 attribute with an OID and associated value.
"""
if not isinstance(oid, ObjectIdentifier):
raise TypeError("oid must be an ObjectIdentifier")
if not isinstance(value, bytes):
raise TypeError("value must be bytes")
_reject_duplicate_attribute(oid, self._attributes)
return CertificateSigningRequestBuilder(
self._subject_name,
self._extensions,
self._attributes + [(oid, value)],
)
def sign(self, private_key, algorithm, backend=None):
"""
Signs the request using the requestor's private key.
"""
backend = _get_backend(backend)
if self._subject_name is None:
raise ValueError("A CertificateSigningRequest must have a subject")
return backend.create_x509_csr(self, private_key, algorithm)
class CertificateBuilder(object):
def __init__(
self,
issuer_name=None,
subject_name=None,
public_key=None,
serial_number=None,
not_valid_before=None,
not_valid_after=None,
extensions=[],
):
self._version = Version.v3
self._issuer_name = issuer_name
self._subject_name = subject_name
self._public_key = public_key
self._serial_number = serial_number
self._not_valid_before = not_valid_before
self._not_valid_after = not_valid_after
self._extensions = extensions
def issuer_name(self, name):
"""
Sets the CA's distinguished name.
"""
if not isinstance(name, Name):
raise TypeError("Expecting x509.Name object.")
if self._issuer_name is not None:
raise ValueError("The issuer name may only be set once.")
return CertificateBuilder(
name,
self._subject_name,
self._public_key,
self._serial_number,
self._not_valid_before,
self._not_valid_after,
self._extensions,
)
def subject_name(self, name):
"""
Sets the requestor's distinguished name.
"""
if not isinstance(name, Name):
raise TypeError("Expecting x509.Name object.")
if self._subject_name is not None:
raise ValueError("The subject name may only be set once.")
return CertificateBuilder(
self._issuer_name,
name,
self._public_key,
self._serial_number,
self._not_valid_before,
self._not_valid_after,
self._extensions,
)
def public_key(self, key):
"""
Sets the requestor's public key (as found in the signing request).
"""
if not isinstance(
key,
(
dsa.DSAPublicKey,
rsa.RSAPublicKey,
ec.EllipticCurvePublicKey,
ed25519.Ed25519PublicKey,
ed448.Ed448PublicKey,
),
):
raise TypeError(
"Expecting one of DSAPublicKey, RSAPublicKey,"
" EllipticCurvePublicKey, Ed25519PublicKey or"
" Ed448PublicKey."
)
if self._public_key is not None:
raise ValueError("The public key may only be set once.")
return CertificateBuilder(
self._issuer_name,
self._subject_name,
key,
self._serial_number,
self._not_valid_before,
self._not_valid_after,
self._extensions,
)
def serial_number(self, number):
"""
Sets the certificate serial number.
"""
if not isinstance(number, six.integer_types):
raise TypeError("Serial number must be of integral type.")
if self._serial_number is not None:
raise ValueError("The serial number may only be set once.")
if number <= 0:
raise ValueError("The serial number should be positive.")
# ASN.1 integers are always signed, so most significant bit must be
# zero.
if number.bit_length() >= 160: # As defined in RFC 5280
raise ValueError(
"The serial number should not be more than 159 " "bits."
)
return CertificateBuilder(
self._issuer_name,
self._subject_name,
self._public_key,
number,
self._not_valid_before,
self._not_valid_after,
self._extensions,
)
def not_valid_before(self, time):
"""
Sets the certificate activation time.
"""
if not isinstance(time, datetime.datetime):
raise TypeError("Expecting datetime object.")
if self._not_valid_before is not None:
raise ValueError("The not valid before may only be set once.")
time = _convert_to_naive_utc_time(time)
if time < _EARLIEST_UTC_TIME:
raise ValueError(
"The not valid before date must be on or after"
" 1950 January 1)."
)
if self._not_valid_after is not None and time > self._not_valid_after:
raise ValueError(
"The not valid before date must be before the not valid after "
"date."
)
return CertificateBuilder(
self._issuer_name,
self._subject_name,
self._public_key,
self._serial_number,
time,
self._not_valid_after,
self._extensions,
)
def not_valid_after(self, time):
"""
Sets the certificate expiration time.
"""
if not isinstance(time, datetime.datetime):
raise TypeError("Expecting datetime object.")
if self._not_valid_after is not None:
raise ValueError("The not valid after may only be set once.")
time = _convert_to_naive_utc_time(time)
if time < _EARLIEST_UTC_TIME:
raise ValueError(
"The not valid after date must be on or after"
" 1950 January 1."
)
if (
self._not_valid_before is not None
and time < self._not_valid_before
):
raise ValueError(
"The not valid after date must be after the not valid before "
"date."
)
return CertificateBuilder(
self._issuer_name,
self._subject_name,
self._public_key,
self._serial_number,
self._not_valid_before,
time,
self._extensions,
)
def add_extension(self, extension, critical):
"""
Adds an X.509 extension to the certificate.
"""
if not isinstance(extension, ExtensionType):
raise TypeError("extension must be an ExtensionType")
extension = Extension(extension.oid, critical, extension)
_reject_duplicate_extension(extension, self._extensions)
return CertificateBuilder(
self._issuer_name,
self._subject_name,
self._public_key,
self._serial_number,
self._not_valid_before,
self._not_valid_after,
self._extensions + [extension],
)
def sign(self, private_key, algorithm, backend=None):
"""
Signs the certificate using the CA's private key.
"""
backend = _get_backend(backend)
if self._subject_name is None:
raise ValueError("A certificate must have a subject name")
if self._issuer_name is None:
raise ValueError("A certificate must have an issuer name")
if self._serial_number is None:
raise ValueError("A certificate must have a serial number")
if self._not_valid_before is None:
raise ValueError("A certificate must have a not valid before time")
if self._not_valid_after is None:
raise ValueError("A certificate must have a not valid after time")
if self._public_key is None:
raise ValueError("A certificate must have a public key")
return backend.create_x509_certificate(self, private_key, algorithm)
class CertificateRevocationListBuilder(object):
def __init__(
self,
issuer_name=None,
last_update=None,
next_update=None,
extensions=[],
revoked_certificates=[],
):
self._issuer_name = issuer_name
self._last_update = last_update
self._next_update = next_update
self._extensions = extensions
self._revoked_certificates = revoked_certificates
def issuer_name(self, issuer_name):
if not isinstance(issuer_name, Name):
raise TypeError("Expecting x509.Name object.")
if self._issuer_name is not None:
raise ValueError("The issuer name may only be set once.")
return CertificateRevocationListBuilder(
issuer_name,
self._last_update,
self._next_update,
self._extensions,
self._revoked_certificates,
)
def last_update(self, last_update):
if not isinstance(last_update, datetime.datetime):
raise TypeError("Expecting datetime object.")
if self._last_update is not None:
raise ValueError("Last update may only be set once.")
last_update = _convert_to_naive_utc_time(last_update)
if last_update < _EARLIEST_UTC_TIME:
raise ValueError(
"The last update date must be on or after" " 1950 January 1."
)
if self._next_update is not None and last_update > self._next_update:
raise ValueError(
"The last update date must be before the next update date."
)
return CertificateRevocationListBuilder(
self._issuer_name,
last_update,
self._next_update,
self._extensions,
self._revoked_certificates,
)
def next_update(self, next_update):
if not isinstance(next_update, datetime.datetime):
raise TypeError("Expecting datetime object.")
if self._next_update is not None:
raise ValueError("Last update may only be set once.")
next_update = _convert_to_naive_utc_time(next_update)
if next_update < _EARLIEST_UTC_TIME:
raise ValueError(
"The last update date must be on or after" " 1950 January 1."
)
if self._last_update is not None and next_update < self._last_update:
raise ValueError(
"The next update date must be after the last update date."
)
return CertificateRevocationListBuilder(
self._issuer_name,
self._last_update,
next_update,
self._extensions,
self._revoked_certificates,
)
def add_extension(self, extension, critical):
"""
Adds an X.509 extension to the certificate revocation list.
"""
if not isinstance(extension, ExtensionType):
raise TypeError("extension must be an ExtensionType")
extension = Extension(extension.oid, critical, extension)
_reject_duplicate_extension(extension, self._extensions)
return CertificateRevocationListBuilder(
self._issuer_name,
self._last_update,
self._next_update,
self._extensions + [extension],
self._revoked_certificates,
)
def add_revoked_certificate(self, revoked_certificate):
"""
Adds a revoked certificate to the CRL.
"""
if not isinstance(revoked_certificate, RevokedCertificate):
raise TypeError("Must be an instance of RevokedCertificate")
return CertificateRevocationListBuilder(
self._issuer_name,
self._last_update,
self._next_update,
self._extensions,
self._revoked_certificates + [revoked_certificate],
)
def sign(self, private_key, algorithm, backend=None):
backend = _get_backend(backend)
if self._issuer_name is None:
raise ValueError("A CRL must have an issuer name")
if self._last_update is None:
raise ValueError("A CRL must have a last update time")
if self._next_update is None:
raise ValueError("A CRL must have a next update time")
return backend.create_x509_crl(self, private_key, algorithm)
class RevokedCertificateBuilder(object):
def __init__(
self, serial_number=None, revocation_date=None, extensions=[]
):
self._serial_number = serial_number
self._revocation_date = revocation_date
self._extensions = extensions
def serial_number(self, number):
if not isinstance(number, six.integer_types):
raise TypeError("Serial number must be of integral type.")
if self._serial_number is not None:
raise ValueError("The serial number may only be set once.")
if number <= 0:
raise ValueError("The serial number should be positive")
# ASN.1 integers are always signed, so most significant bit must be
# zero.
if number.bit_length() >= 160: # As defined in RFC 5280
raise ValueError(
"The serial number should not be more than 159 " "bits."
)
return RevokedCertificateBuilder(
number, self._revocation_date, self._extensions
)
def revocation_date(self, time):
if not isinstance(time, datetime.datetime):
raise TypeError("Expecting datetime object.")
if self._revocation_date is not None:
raise ValueError("The revocation date may only be set once.")
time = _convert_to_naive_utc_time(time)
if time < _EARLIEST_UTC_TIME:
raise ValueError(
"The revocation date must be on or after" " 1950 January 1."
)
return RevokedCertificateBuilder(
self._serial_number, time, self._extensions
)
def add_extension(self, extension, critical):
if not isinstance(extension, ExtensionType):
raise TypeError("extension must be an ExtensionType")
extension = Extension(extension.oid, critical, extension)
_reject_duplicate_extension(extension, self._extensions)
return RevokedCertificateBuilder(
self._serial_number,
self._revocation_date,
self._extensions + [extension],
)
def build(self, backend=None):
backend = _get_backend(backend)
if self._serial_number is None:
raise ValueError("A revoked certificate must have a serial number")
if self._revocation_date is None:
raise ValueError(
"A revoked certificate must have a revocation date"
)
return backend.create_x509_revoked_certificate(self)
def random_serial_number():
return utils.int_from_bytes(os.urandom(20), "big") >> 1
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