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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
from enum import Enum
import six
from cryptography import x509
from cryptography.hazmat.primitives import hashes
from cryptography.x509.base import (
_EARLIEST_UTC_TIME,
_convert_to_naive_utc_time,
_reject_duplicate_extension,
)
_OIDS_TO_HASH = {
"1.3.14.3.2.26": hashes.SHA1(),
"2.16.840.1.101.3.4.2.4": hashes.SHA224(),
"2.16.840.1.101.3.4.2.1": hashes.SHA256(),
"2.16.840.1.101.3.4.2.2": hashes.SHA384(),
"2.16.840.1.101.3.4.2.3": hashes.SHA512(),
}
class OCSPResponderEncoding(Enum):
HASH = "By Hash"
NAME = "By Name"
class OCSPResponseStatus(Enum):
SUCCESSFUL = 0
MALFORMED_REQUEST = 1
INTERNAL_ERROR = 2
TRY_LATER = 3
SIG_REQUIRED = 5
UNAUTHORIZED = 6
_RESPONSE_STATUS_TO_ENUM = {x.value: x for x in OCSPResponseStatus}
_ALLOWED_HASHES = (
hashes.SHA1,
hashes.SHA224,
hashes.SHA256,
hashes.SHA384,
hashes.SHA512,
)
def _verify_algorithm(algorithm):
if not isinstance(algorithm, _ALLOWED_HASHES):
raise ValueError(
"Algorithm must be SHA1, SHA224, SHA256, SHA384, or SHA512"
)
class OCSPCertStatus(Enum):
GOOD = 0
REVOKED = 1
UNKNOWN = 2
_CERT_STATUS_TO_ENUM = {x.value: x for x in OCSPCertStatus}
def load_der_ocsp_request(data):
from cryptography.hazmat.backends.openssl.backend import backend
return backend.load_der_ocsp_request(data)
def load_der_ocsp_response(data):
from cryptography.hazmat.backends.openssl.backend import backend
return backend.load_der_ocsp_response(data)
class OCSPRequestBuilder(object):
def __init__(self, request=None, extensions=[]):
self._request = request
self._extensions = extensions
def add_certificate(self, cert, issuer, algorithm):
if self._request is not None:
raise ValueError("Only one certificate can be added to a request")
_verify_algorithm(algorithm)
if not isinstance(cert, x509.Certificate) or not isinstance(
issuer, x509.Certificate
):
raise TypeError("cert and issuer must be a Certificate")
return OCSPRequestBuilder((cert, issuer, algorithm), self._extensions)
def add_extension(self, extension, critical):
if not isinstance(extension, x509.ExtensionType):
raise TypeError("extension must be an ExtensionType")
extension = x509.Extension(extension.oid, critical, extension)
_reject_duplicate_extension(extension, self._extensions)
return OCSPRequestBuilder(
self._request, self._extensions + [extension]
)
def build(self):
from cryptography.hazmat.backends.openssl.backend import backend
if self._request is None:
raise ValueError("You must add a certificate before building")
return backend.create_ocsp_request(self)
class _SingleResponse(object):
def __init__(
self,
cert,
issuer,
algorithm,
cert_status,
this_update,
next_update,
revocation_time,
revocation_reason,
):
if not isinstance(cert, x509.Certificate) or not isinstance(
issuer, x509.Certificate
):
raise TypeError("cert and issuer must be a Certificate")
_verify_algorithm(algorithm)
if not isinstance(this_update, datetime.datetime):
raise TypeError("this_update must be a datetime object")
if next_update is not None and not isinstance(
next_update, datetime.datetime
):
raise TypeError("next_update must be a datetime object or None")
self._cert = cert
self._issuer = issuer
self._algorithm = algorithm
self._this_update = this_update
self._next_update = next_update
if not isinstance(cert_status, OCSPCertStatus):
raise TypeError(
"cert_status must be an item from the OCSPCertStatus enum"
)
if cert_status is not OCSPCertStatus.REVOKED:
if revocation_time is not None:
raise ValueError(
"revocation_time can only be provided if the certificate "
"is revoked"
)
if revocation_reason is not None:
raise ValueError(
"revocation_reason can only be provided if the certificate"
" is revoked"
)
else:
if not isinstance(revocation_time, datetime.datetime):
raise TypeError("revocation_time must be a datetime object")
revocation_time = _convert_to_naive_utc_time(revocation_time)
if revocation_time < _EARLIEST_UTC_TIME:
raise ValueError(
"The revocation_time must be on or after"
" 1950 January 1."
)
if revocation_reason is not None and not isinstance(
revocation_reason, x509.ReasonFlags
):
raise TypeError(
"revocation_reason must be an item from the ReasonFlags "
"enum or None"
)
self._cert_status = cert_status
self._revocation_time = revocation_time
self._revocation_reason = revocation_reason
class OCSPResponseBuilder(object):
def __init__(
self, response=None, responder_id=None, certs=None, extensions=[]
):
self._response = response
self._responder_id = responder_id
self._certs = certs
self._extensions = extensions
def add_response(
self,
cert,
issuer,
algorithm,
cert_status,
this_update,
next_update,
revocation_time,
revocation_reason,
):
if self._response is not None:
raise ValueError("Only one response per OCSPResponse.")
singleresp = _SingleResponse(
cert,
issuer,
algorithm,
cert_status,
this_update,
next_update,
revocation_time,
revocation_reason,
)
return OCSPResponseBuilder(
singleresp,
self._responder_id,
self._certs,
self._extensions,
)
def responder_id(self, encoding, responder_cert):
if self._responder_id is not None:
raise ValueError("responder_id can only be set once")
if not isinstance(responder_cert, x509.Certificate):
raise TypeError("responder_cert must be a Certificate")
if not isinstance(encoding, OCSPResponderEncoding):
raise TypeError(
"encoding must be an element from OCSPResponderEncoding"
)
return OCSPResponseBuilder(
self._response,
(responder_cert, encoding),
self._certs,
self._extensions,
)
def certificates(self, certs):
if self._certs is not None:
raise ValueError("certificates may only be set once")
certs = list(certs)
if len(certs) == 0:
raise ValueError("certs must not be an empty list")
if not all(isinstance(x, x509.Certificate) for x in certs):
raise TypeError("certs must be a list of Certificates")
return OCSPResponseBuilder(
self._response,
self._responder_id,
certs,
self._extensions,
)
def add_extension(self, extension, critical):
if not isinstance(extension, x509.ExtensionType):
raise TypeError("extension must be an ExtensionType")
extension = x509.Extension(extension.oid, critical, extension)
_reject_duplicate_extension(extension, self._extensions)
return OCSPResponseBuilder(
self._response,
self._responder_id,
self._certs,
self._extensions + [extension],
)
def sign(self, private_key, algorithm):
from cryptography.hazmat.backends.openssl.backend import backend
if self._response is None:
raise ValueError("You must add a response before signing")
if self._responder_id is None:
raise ValueError("You must add a responder_id before signing")
return backend.create_ocsp_response(
OCSPResponseStatus.SUCCESSFUL, self, private_key, algorithm
)
@classmethod
def build_unsuccessful(cls, response_status):
from cryptography.hazmat.backends.openssl.backend import backend
if not isinstance(response_status, OCSPResponseStatus):
raise TypeError(
"response_status must be an item from OCSPResponseStatus"
)
if response_status is OCSPResponseStatus.SUCCESSFUL:
raise ValueError("response_status cannot be SUCCESSFUL")
return backend.create_ocsp_response(response_status, None, None, None)
@six.add_metaclass(abc.ABCMeta)
class OCSPRequest(object):
@abc.abstractproperty
def issuer_key_hash(self):
"""
The hash of the issuer public key
"""
@abc.abstractproperty
def issuer_name_hash(self):
"""
The hash of the issuer name
"""
@abc.abstractproperty
def hash_algorithm(self):
"""
The hash algorithm used in the issuer name and key hashes
"""
@abc.abstractproperty
def serial_number(self):
"""
The serial number of the cert whose status is being checked
"""
@abc.abstractmethod
def public_bytes(self, encoding):
"""
Serializes the request to DER
"""
@abc.abstractproperty
def extensions(self):
"""
The list of request extensions. Not single request extensions.
"""
@six.add_metaclass(abc.ABCMeta)
class OCSPResponse(object):
@abc.abstractproperty
def response_status(self):
"""
The status of the response. This is a value from the OCSPResponseStatus
enumeration
"""
@abc.abstractproperty
def signature_algorithm_oid(self):
"""
The ObjectIdentifier of the signature algorithm
"""
@abc.abstractproperty
def signature_hash_algorithm(self):
"""
Returns a HashAlgorithm corresponding to the type of the digest signed
"""
@abc.abstractproperty
def signature(self):
"""
The signature bytes
"""
@abc.abstractproperty
def tbs_response_bytes(self):
"""
The tbsResponseData bytes
"""
@abc.abstractproperty
def certificates(self):
"""
A list of certificates used to help build a chain to verify the OCSP
response. This situation occurs when the OCSP responder uses a delegate
certificate.
"""
@abc.abstractproperty
def responder_key_hash(self):
"""
The responder's key hash or None
"""
@abc.abstractproperty
def responder_name(self):
"""
The responder's Name or None
"""
@abc.abstractproperty
def produced_at(self):
"""
The time the response was produced
"""
@abc.abstractproperty
def certificate_status(self):
"""
The status of the certificate (an element from the OCSPCertStatus enum)
"""
@abc.abstractproperty
def revocation_time(self):
"""
The date of when the certificate was revoked or None if not
revoked.
"""
@abc.abstractproperty
def revocation_reason(self):
"""
The reason the certificate was revoked or None if not specified or
not revoked.
"""
@abc.abstractproperty
def this_update(self):
"""
The most recent time at which the status being indicated is known by
the responder to have been correct
"""
@abc.abstractproperty
def next_update(self):
"""
The time when newer information will be available
"""
@abc.abstractproperty
def issuer_key_hash(self):
"""
The hash of the issuer public key
"""
@abc.abstractproperty
def issuer_name_hash(self):
"""
The hash of the issuer name
"""
@abc.abstractproperty
def hash_algorithm(self):
"""
The hash algorithm used in the issuer name and key hashes
"""
@abc.abstractproperty
def serial_number(self):
"""
The serial number of the cert whose status is being checked
"""
@abc.abstractproperty
def extensions(self):
"""
The list of response extensions. Not single response extensions.
"""
@abc.abstractproperty
def single_extensions(self):
"""
The list of single response extensions. Not response extensions.
"""
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