/
pkcs7.py
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/
pkcs7.py
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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.
import typing
from cryptography import utils
from cryptography import x509
from cryptography.hazmat.primitives import hashes, serialization
from cryptography.hazmat.primitives.asymmetric import ec, rsa
from cryptography.utils import _check_byteslike
def load_pem_pkcs7_certificates(data: bytes) -> typing.List[x509.Certificate]:
from cryptography.hazmat.backends.openssl.backend import backend
return backend.load_pem_pkcs7_certificates(data)
def load_der_pkcs7_certificates(data: bytes) -> typing.List[x509.Certificate]:
from cryptography.hazmat.backends.openssl.backend import backend
return backend.load_der_pkcs7_certificates(data)
def serialize_certificates(
certs: typing.List[x509.Certificate],
encoding: serialization.Encoding,
) -> bytes:
from cryptography.hazmat.backends.openssl.backend import backend
return backend.pkcs7_serialize_certificates(certs, encoding)
_ALLOWED_PKCS7_HASH_TYPES = typing.Union[
hashes.SHA1,
hashes.SHA224,
hashes.SHA256,
hashes.SHA384,
hashes.SHA512,
]
_ALLOWED_PRIVATE_KEY_TYPES = typing.Union[
rsa.RSAPrivateKey, ec.EllipticCurvePrivateKey
]
class PKCS7Options(utils.Enum):
Text = "Add text/plain MIME type"
Binary = "Don't translate input data into canonical MIME format"
DetachedSignature = "Don't embed data in the PKCS7 structure"
NoCapabilities = "Don't embed SMIME capabilities"
NoAttributes = "Don't embed authenticatedAttributes"
NoCerts = "Don't embed signer certificate"
class PKCS7SignatureBuilder:
def __init__(
self,
data: typing.Optional[bytes] = None,
signers: typing.List[
typing.Tuple[
x509.Certificate,
_ALLOWED_PRIVATE_KEY_TYPES,
_ALLOWED_PKCS7_HASH_TYPES,
]
] = [],
additional_certs: typing.List[x509.Certificate] = [],
):
self._data = data
self._signers = signers
self._additional_certs = additional_certs
def set_data(self, data: bytes) -> "PKCS7SignatureBuilder":
_check_byteslike("data", data)
if self._data is not None:
raise ValueError("data may only be set once")
return PKCS7SignatureBuilder(data, self._signers)
def add_signer(
self,
certificate: x509.Certificate,
private_key: _ALLOWED_PRIVATE_KEY_TYPES,
hash_algorithm: _ALLOWED_PKCS7_HASH_TYPES,
) -> "PKCS7SignatureBuilder":
if not isinstance(
hash_algorithm,
(
hashes.SHA1,
hashes.SHA224,
hashes.SHA256,
hashes.SHA384,
hashes.SHA512,
),
):
raise TypeError(
"hash_algorithm must be one of hashes.SHA1, SHA224, "
"SHA256, SHA384, or SHA512"
)
if not isinstance(certificate, x509.Certificate):
raise TypeError("certificate must be a x509.Certificate")
if not isinstance(
private_key, (rsa.RSAPrivateKey, ec.EllipticCurvePrivateKey)
):
raise TypeError("Only RSA & EC keys are supported at this time.")
return PKCS7SignatureBuilder(
self._data,
self._signers + [(certificate, private_key, hash_algorithm)],
)
def add_certificate(
self, certificate: x509.Certificate
) -> "PKCS7SignatureBuilder":
if not isinstance(certificate, x509.Certificate):
raise TypeError("certificate must be a x509.Certificate")
return PKCS7SignatureBuilder(
self._data, self._signers, self._additional_certs + [certificate]
)
def sign(
self,
encoding: serialization.Encoding,
options: typing.Iterable[PKCS7Options],
backend: typing.Any = None,
) -> bytes:
if len(self._signers) == 0:
raise ValueError("Must have at least one signer")
if self._data is None:
raise ValueError("You must add data to sign")
options = list(options)
if not all(isinstance(x, PKCS7Options) for x in options):
raise ValueError("options must be from the PKCS7Options enum")
if encoding not in (
serialization.Encoding.PEM,
serialization.Encoding.DER,
serialization.Encoding.SMIME,
):
raise ValueError(
"Must be PEM, DER, or SMIME from the Encoding enum"
)
# Text is a meaningless option unless it is accompanied by
# DetachedSignature
if (
PKCS7Options.Text in options
and PKCS7Options.DetachedSignature not in options
):
raise ValueError(
"When passing the Text option you must also pass "
"DetachedSignature"
)
if PKCS7Options.Text in options and encoding in (
serialization.Encoding.DER,
serialization.Encoding.PEM,
):
raise ValueError(
"The Text option is only available for SMIME serialization"
)
# No attributes implies no capabilities so we'll error if you try to
# pass both.
if (
PKCS7Options.NoAttributes in options
and PKCS7Options.NoCapabilities in options
):
raise ValueError(
"NoAttributes is a superset of NoCapabilities. Do not pass "
"both values."
)
from cryptography.hazmat.backends.openssl.backend import (
backend as ossl,
)
return ossl.pkcs7_sign(self, encoding, options)