diff options
| -rw-r--r-- | docs/x509/reference.rst | 30 | ||||
| -rw-r--r-- | src/cryptography/x509.py | 49 | ||||
| -rw-r--r-- | tests/test_x509_ext.py | 19 |
3 files changed, 80 insertions, 18 deletions
diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst index dfa91fac..a05be164 100644 --- a/docs/x509/reference.rst +++ b/docs/x509/reference.rst @@ -1160,6 +1160,28 @@ X.509 Extensions The serial number of the issuer's issuer. + .. classmethod:: from_issuer_public_key(public_key) + + .. versionadded:: 1.0 + + Creates a new AuthorityKeyIdentifier instance using the public key + provided to generate the appropriate digest. This should be the + **issuer public key**. The resulting object will contain a + :attr:`~cryptography.x509.AuthorityKeyIdentifier.key_identifier`. + The generated digest is the SHA1 hash of the ``subjectPublicKey`` A + SN.1 bit string. This is the first recommendation in :rfc:`5280` + section 4.2.1.2. + + :param certificate: The issuing :class:`~cryptography.x509.Certificate`. + + .. doctest:: + + >>> from cryptography import x509 + >>> from cryptography.hazmat.backends import default_backend + >>> cert = x509.load_pem_x509_certificate(pem_data, default_backend()) + >>> x509.AuthorityKeyIdentifier.from_issuer_public_key(cert.public_key()) + <AuthorityKeyIdentifier(key_identifier='X\x01\x84$\x1b\xbc+R\x94J=\xa5\x10r\x14Q\xf5\xaf:\xc9', authority_cert_issuer=None, authority_cert_serial_number=None)> + .. class:: SubjectKeyIdentifier .. versionadded:: 0.9 @@ -1198,6 +1220,14 @@ X.509 Extensions , or :class:`~cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePublicKey`. + .. doctest:: + + >>> from cryptography import x509 + >>> from cryptography.hazmat.backends import default_backend + >>> cert = x509.load_pem_x509_certificate(pem_data, default_backend()) + >>> x509.SubjectKeyIdentifier.from_public_key(cert.public_key()) + <SubjectKeyIdentifier(digest='X\x01\x84$\x1b\xbc+R\x94J=\xa5\x10r\x14Q\xf5\xaf:\xc9')> + .. class:: SubjectAlternativeName .. versionadded:: 0.9 diff --git a/src/cryptography/x509.py b/src/cryptography/x509.py index 5ed3c094..3f306e3a 100644 --- a/src/cryptography/x509.py +++ b/src/cryptography/x509.py @@ -32,6 +32,27 @@ class _SubjectPublicKeyInfo(univ.Sequence): ) +def _key_identifier_from_public_key(public_key): + # This is a very slow way to do this. + serialized = public_key.public_bytes( + serialization.Encoding.DER, + serialization.PublicFormat.SubjectPublicKeyInfo + ) + spki, remaining = decoder.decode( + serialized, asn1Spec=_SubjectPublicKeyInfo() + ) + # the univ.BitString object is a tuple of bits. We need bytes and + # pyasn1 really doesn't want to give them to us. To get it we'll + # build an integer and convert that to bytes. + assert not remaining + bits = 0 + for bit in spki.getComponentByName("subjectPublicKey"): + bits = bits << 1 | bit + + data = utils.int_to_bytes(bits) + return hashlib.sha1(data).digest() + + _OID_NAMES = { "2.5.4.3": "commonName", "2.5.4.6": "countryName", @@ -710,24 +731,7 @@ class SubjectKeyIdentifier(object): @classmethod def from_public_key(cls, public_key): - # This is a very slow way to do this. - serialized = public_key.public_bytes( - serialization.Encoding.DER, - serialization.PublicFormat.SubjectPublicKeyInfo - ) - spki, remaining = decoder.decode( - serialized, asn1Spec=_SubjectPublicKeyInfo() - ) - assert not remaining - # the univ.BitString object is a tuple of bits. We need bytes and - # pyasn1 really doesn't want to give them to us. To get it we'll - # build an integer and convert that to bytes. - bits = 0 - for bit in spki.getComponentByName("subjectPublicKey"): - bits = bits << 1 | bit - - data = utils.int_to_bytes(bits) - return cls(hashlib.sha1(data).digest()) + return cls(_key_identifier_from_public_key(public_key)) digest = utils.read_only_property("_digest") @@ -1318,6 +1322,15 @@ class AuthorityKeyIdentifier(object): self._authority_cert_issuer = authority_cert_issuer self._authority_cert_serial_number = authority_cert_serial_number + @classmethod + def from_issuer_public_key(cls, public_key): + digest = _key_identifier_from_public_key(public_key) + return cls( + key_identifier=digest, + authority_cert_issuer=None, + authority_cert_serial_number=None + ) + def __repr__(self): return ( "<AuthorityKeyIdentifier(key_identifier={0.key_identifier!r}, " diff --git a/tests/test_x509_ext.py b/tests/test_x509_ext.py index 73cdfc5f..40231b93 100644 --- a/tests/test_x509_ext.py +++ b/tests/test_x509_ext.py @@ -2112,6 +2112,25 @@ class TestAuthorityKeyIdentifierExtension(object): ] assert ext.value.authority_cert_serial_number == 3 + def test_from_certificate(self, backend): + issuer_cert = _load_cert( + os.path.join("x509", "rapidssl_sha256_ca_g3.pem"), + x509.load_pem_x509_certificate, + backend + ) + cert = _load_cert( + os.path.join("x509", "cryptography.io.pem"), + x509.load_pem_x509_certificate, + backend + ) + ext = cert.extensions.get_extension_for_oid( + x509.OID_AUTHORITY_KEY_IDENTIFIER + ) + aki = x509.AuthorityKeyIdentifier.from_issuer_public_key( + issuer_cert.public_key() + ) + assert ext.value == aki + class TestNameConstraints(object): def test_ipaddress_wrong_type(self): |