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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 calendar
import collections
import itertools
from contextlib import contextmanager
import idna
import six
from cryptography import utils, x509
from cryptography.exceptions import (
InternalError, UnsupportedAlgorithm, _Reasons
)
from cryptography.hazmat.backends.interfaces import (
CMACBackend, CipherBackend, DERSerializationBackend, DSABackend,
EllipticCurveBackend, HMACBackend, HashBackend, PBKDF2HMACBackend,
PEMSerializationBackend, RSABackend, X509Backend
)
from cryptography.hazmat.backends.openssl.ciphers import (
_AESCTRCipherContext, _CipherContext
)
from cryptography.hazmat.backends.openssl.cmac import _CMACContext
from cryptography.hazmat.backends.openssl.dsa import (
_DSAParameters, _DSAPrivateKey, _DSAPublicKey
)
from cryptography.hazmat.backends.openssl.ec import (
_EllipticCurvePrivateKey, _EllipticCurvePublicKey
)
from cryptography.hazmat.backends.openssl.hashes import _HashContext
from cryptography.hazmat.backends.openssl.hmac import _HMACContext
from cryptography.hazmat.backends.openssl.rsa import (
_RSAPrivateKey, _RSAPublicKey
)
from cryptography.hazmat.backends.openssl.x509 import (
_Certificate, _CertificateSigningRequest
)
from cryptography.hazmat.bindings.openssl.binding import Binding
from cryptography.hazmat.primitives import hashes, serialization
from cryptography.hazmat.primitives.asymmetric import dsa, ec, rsa
from cryptography.hazmat.primitives.asymmetric.padding import (
MGF1, OAEP, PKCS1v15, PSS
)
from cryptography.hazmat.primitives.ciphers.algorithms import (
AES, ARC4, Blowfish, CAST5, Camellia, IDEA, SEED, TripleDES
)
from cryptography.hazmat.primitives.ciphers.modes import (
CBC, CFB, CFB8, CTR, ECB, GCM, OFB
)
_MemoryBIO = collections.namedtuple("_MemoryBIO", ["bio", "char_ptr"])
_OpenSSLError = collections.namedtuple("_OpenSSLError",
["code", "lib", "func", "reason"])
def _encode_asn1_int(backend, x):
"""
Converts a python integer to a ASN1_INTEGER. The returned ASN1_INTEGER will
not be garbage collected (to support adding them to structs that take
ownership of the object). Be sure to register it for GC if it will be
discarded after use.
"""
# Convert Python integer to OpenSSL "bignum" in case value exceeds
# machine's native integer limits (note: `int_to_bn` doesn't automatically
# GC).
i = backend._int_to_bn(x)
i = backend._ffi.gc(i, backend._lib.BN_free)
# Wrap in a ASN.1 integer. Don't GC -- as documented.
i = backend._lib.BN_to_ASN1_INTEGER(i, backend._ffi.NULL)
assert i != backend._ffi.NULL
return i
def _encode_asn1_str(backend, data, length):
"""
Create an ASN1_OCTET_STRING from a Python byte string.
"""
s = backend._lib.ASN1_OCTET_STRING_new()
res = backend._lib.ASN1_OCTET_STRING_set(s, data, length)
assert res == 1
return s
def _encode_asn1_str_gc(backend, data, length):
s = _encode_asn1_str(backend, data, length)
s = backend._ffi.gc(s, backend._lib.ASN1_OCTET_STRING_free)
return s
def _make_asn1_int(backend, x):
i = backend._lib.ASN1_INTEGER_new()
# i = backend._ffi.gc(i, backend._lib.ASN1_INTEGER_free)
backend._lib.ASN1_INTEGER_set(i, x)
return i
def _make_asn1_str(backend, x, n=None):
if n is None:
n = len(x)
s = backend._lib.ASN1_OCTET_STRING_new()
# s = backend._ffi.gc(s, backend._lib.ASN1_OCTET_STRING_free)
backend._lib.ASN1_OCTET_STRING_set(s, x, n)
return s
def _encode_name(backend, attributes):
"""
The X509_NAME created will not be gc'd. Use _encode_name_gc if needed.
"""
subject = backend._lib.X509_NAME_new()
for attribute in attributes:
value = attribute.value.encode('utf8')
obj = _txt2obj(backend, attribute.oid.dotted_string)
res = backend._lib.X509_NAME_add_entry_by_OBJ(
subject,
obj,
backend._lib.MBSTRING_UTF8,
value,
-1, -1, 0,
)
assert res == 1
return subject
def _encode_name_gc(backend, attributes):
subject = _encode_name(backend, attributes)
subject = backend._ffi.gc(subject, backend._lib.X509_NAME_free)
return subject
def _txt2obj(backend, name):
"""
Converts a Python string with an ASN.1 object ID in dotted form to a
ASN1_OBJECT.
"""
name = name.encode('ascii')
obj = backend._lib.OBJ_txt2obj(name, 1)
assert obj != backend._ffi.NULL
obj = backend._ffi.gc(obj, backend._lib.ASN1_OBJECT_free)
return obj
def _encode_basic_constraints(backend, basic_constraints):
constraints = backend._lib.BASIC_CONSTRAINTS_new()
constraints = backend._ffi.gc(
constraints, backend._lib.BASIC_CONSTRAINTS_free
)
constraints.ca = 255 if basic_constraints.ca else 0
if basic_constraints.ca:
constraints.pathlen = _encode_asn1_int(
backend, basic_constraints.path_length
)
# Fetch the encoded payload.
pp = backend._ffi.new('unsigned char **')
r = backend._lib.i2d_BASIC_CONSTRAINTS(constraints, pp)
assert r > 0
pp = backend._ffi.gc(
pp, lambda pointer: backend._lib.OPENSSL_free(pointer[0])
)
return pp, r
def _encode_subject_alt_name(backend, san):
general_names = backend._lib.GENERAL_NAMES_new()
assert general_names != backend._ffi.NULL
general_names = backend._ffi.gc(
general_names, backend._lib.GENERAL_NAMES_free
)
for alt_name in san:
if isinstance(alt_name, x509.DNSName):
gn = backend._lib.GENERAL_NAME_new()
assert gn != backend._ffi.NULL
gn.type = backend._lib.GEN_DNS
ia5 = backend._lib.ASN1_IA5STRING_new()
assert ia5 != backend._ffi.NULL
if alt_name.value.startswith(u"*."):
value = b"*." + idna.encode(alt_name.value[2:])
else:
value = idna.encode(alt_name.value)
res = backend._lib.ASN1_STRING_set(ia5, value, len(value))
assert res == 1
gn.d.dNSName = ia5
elif isinstance(alt_name, x509.RegisteredID):
gn = backend._lib.GENERAL_NAME_new()
assert gn != backend._ffi.NULL
gn.type = backend._lib.GEN_RID
obj = backend._lib.OBJ_txt2obj(
alt_name.value.dotted_string.encode('ascii'), 1
)
assert obj != backend._ffi.NULL
gn.d.registeredID = obj
elif isinstance(alt_name, x509.DirectoryName):
gn = backend._lib.GENERAL_NAME_new()
assert gn != backend._ffi.NULL
name = _encode_name(backend, alt_name.value)
gn.type = backend._lib.GEN_DIRNAME
gn.d.directoryName = name
elif isinstance(alt_name, x509.IPAddress):
gn = backend._lib.GENERAL_NAME_new()
assert gn != backend._ffi.NULL
ipaddr = _encode_asn1_str(
backend, alt_name.value.packed, len(alt_name.value.packed)
)
gn.type = backend._lib.GEN_IPADD
gn.d.iPAddress = ipaddr
elif isinstance(alt_name, x509.OtherName):
gn = backend._lib.GENERAL_NAME_new()
assert gn != backend._ffi.NULL
other_name = backend._lib.OTHERNAME_new()
assert other_name != backend._ffi.NULL
type_id = backend._lib.OBJ_txt2obj(
alt_name.type_id.dotted_string.encode('ascii'), 1
)
assert type_id != backend._ffi.NULL
data = backend._ffi.new("unsigned char[]", alt_name.value)
data_ptr_ptr = backend._ffi.new("unsigned char **")
data_ptr_ptr[0] = data
value = backend._lib.d2i_ASN1_TYPE(
backend._ffi.NULL, data_ptr_ptr, len(alt_name.value)
)
if value == backend._ffi.NULL:
backend._consume_errors()
raise ValueError("Invalid ASN.1 data")
other_name.type_id = type_id
other_name.value = value
gn.type = backend._lib.GEN_OTHERNAME
gn.d.otherName = other_name
elif isinstance(alt_name, x509.RFC822Name):
gn = backend._lib.GENERAL_NAME_new()
assert gn != backend._ffi.NULL
asn1_str = _encode_asn1_str(
backend, alt_name._encoded, len(alt_name._encoded)
)
gn.type = backend._lib.GEN_EMAIL
gn.d.rfc822Name = asn1_str
elif isinstance(alt_name, x509.UniformResourceIdentifier):
gn = backend._lib.GENERAL_NAME_new()
assert gn != backend._ffi.NULL
asn1_str = _encode_asn1_str(
backend, alt_name._encoded, len(alt_name._encoded)
)
gn.type = backend._lib.GEN_URI
gn.d.uniformResourceIdentifier = asn1_str
else:
raise ValueError(
"{0} is an unknown GeneralName type".format(alt_name)
)
res = backend._lib.sk_GENERAL_NAME_push(general_names, gn)
assert res != 0
pp = backend._ffi.new("unsigned char **")
r = backend._lib.i2d_GENERAL_NAMES(general_names, pp)
assert r > 0
pp = backend._ffi.gc(
pp, lambda pointer: backend._lib.OPENSSL_free(pointer[0])
)
return pp, r
@utils.register_interface(CipherBackend)
@utils.register_interface(CMACBackend)
@utils.register_interface(DERSerializationBackend)
@utils.register_interface(DSABackend)
@utils.register_interface(EllipticCurveBackend)
@utils.register_interface(HashBackend)
@utils.register_interface(HMACBackend)
@utils.register_interface(PBKDF2HMACBackend)
@utils.register_interface(RSABackend)
@utils.register_interface(PEMSerializationBackend)
@utils.register_interface(X509Backend)
class Backend(object):
"""
OpenSSL API binding interfaces.
"""
name = "openssl"
def __init__(self):
self._binding = Binding()
self._ffi = self._binding.ffi
self._lib = self._binding.lib
self._binding.init_static_locks()
# adds all ciphers/digests for EVP
self._lib.OpenSSL_add_all_algorithms()
# registers available SSL/TLS ciphers and digests
self._lib.SSL_library_init()
# loads error strings for libcrypto and libssl functions
self._lib.SSL_load_error_strings()
self._cipher_registry = {}
self._register_default_ciphers()
self.activate_osrandom_engine()
def activate_builtin_random(self):
# Obtain a new structural reference.
e = self._lib.ENGINE_get_default_RAND()
if e != self._ffi.NULL:
self._lib.ENGINE_unregister_RAND(e)
# Reset the RNG to use the new engine.
self._lib.RAND_cleanup()
# decrement the structural reference from get_default_RAND
res = self._lib.ENGINE_finish(e)
assert res == 1
def activate_osrandom_engine(self):
# Unregister and free the current engine.
self.activate_builtin_random()
# Fetches an engine by id and returns it. This creates a structural
# reference.
e = self._lib.ENGINE_by_id(self._binding._osrandom_engine_id)
assert e != self._ffi.NULL
# Initialize the engine for use. This adds a functional reference.
res = self._lib.ENGINE_init(e)
assert res == 1
# Set the engine as the default RAND provider.
res = self._lib.ENGINE_set_default_RAND(e)
assert res == 1
# Decrement the structural ref incremented by ENGINE_by_id.
res = self._lib.ENGINE_free(e)
assert res == 1
# Decrement the functional ref incremented by ENGINE_init.
res = self._lib.ENGINE_finish(e)
assert res == 1
# Reset the RNG to use the new engine.
self._lib.RAND_cleanup()
def openssl_version_text(self):
"""
Friendly string name of the loaded OpenSSL library. This is not
necessarily the same version as it was compiled against.
Example: OpenSSL 1.0.1e 11 Feb 2013
"""
return self._ffi.string(
self._lib.SSLeay_version(self._lib.SSLEAY_VERSION)
).decode("ascii")
def create_hmac_ctx(self, key, algorithm):
return _HMACContext(self, key, algorithm)
def hash_supported(self, algorithm):
digest = self._lib.EVP_get_digestbyname(algorithm.name.encode("ascii"))
return digest != self._ffi.NULL
def hmac_supported(self, algorithm):
return self.hash_supported(algorithm)
def create_hash_ctx(self, algorithm):
return _HashContext(self, algorithm)
def cipher_supported(self, cipher, mode):
if self._evp_cipher_supported(cipher, mode):
return True
elif isinstance(mode, CTR) and isinstance(cipher, AES):
return True
else:
return False
def _evp_cipher_supported(self, cipher, mode):
try:
adapter = self._cipher_registry[type(cipher), type(mode)]
except KeyError:
return False
evp_cipher = adapter(self, cipher, mode)
return self._ffi.NULL != evp_cipher
def register_cipher_adapter(self, cipher_cls, mode_cls, adapter):
if (cipher_cls, mode_cls) in self._cipher_registry:
raise ValueError("Duplicate registration for: {0} {1}.".format(
cipher_cls, mode_cls)
)
self._cipher_registry[cipher_cls, mode_cls] = adapter
def _register_default_ciphers(self):
for mode_cls in [CBC, CTR, ECB, OFB, CFB, CFB8]:
self.register_cipher_adapter(
AES,
mode_cls,
GetCipherByName("{cipher.name}-{cipher.key_size}-{mode.name}")
)
for mode_cls in [CBC, CTR, ECB, OFB, CFB]:
self.register_cipher_adapter(
Camellia,
mode_cls,
GetCipherByName("{cipher.name}-{cipher.key_size}-{mode.name}")
)
for mode_cls in [CBC, CFB, CFB8, OFB]:
self.register_cipher_adapter(
TripleDES,
mode_cls,
GetCipherByName("des-ede3-{mode.name}")
)
self.register_cipher_adapter(
TripleDES,
ECB,
GetCipherByName("des-ede3")
)
for mode_cls in [CBC, CFB, OFB, ECB]:
self.register_cipher_adapter(
Blowfish,
mode_cls,
GetCipherByName("bf-{mode.name}")
)
for mode_cls in [CBC, CFB, OFB, ECB]:
self.register_cipher_adapter(
SEED,
mode_cls,
GetCipherByName("seed-{mode.name}")
)
for cipher_cls, mode_cls in itertools.product(
[CAST5, IDEA],
[CBC, OFB, CFB, ECB],
):
self.register_cipher_adapter(
cipher_cls,
mode_cls,
GetCipherByName("{cipher.name}-{mode.name}")
)
self.register_cipher_adapter(
ARC4,
type(None),
GetCipherByName("rc4")
)
self.register_cipher_adapter(
AES,
GCM,
GetCipherByName("{cipher.name}-{cipher.key_size}-{mode.name}")
)
def create_symmetric_encryption_ctx(self, cipher, mode):
if (isinstance(mode, CTR) and isinstance(cipher, AES) and
not self._evp_cipher_supported(cipher, mode)):
# This is needed to provide support for AES CTR mode in OpenSSL
# 0.9.8. It can be removed when we drop 0.9.8 support (RHEL 5
# extended life ends 2020).
return _AESCTRCipherContext(self, cipher, mode)
else:
return _CipherContext(self, cipher, mode, _CipherContext._ENCRYPT)
def create_symmetric_decryption_ctx(self, cipher, mode):
if (isinstance(mode, CTR) and isinstance(cipher, AES) and
not self._evp_cipher_supported(cipher, mode)):
# This is needed to provide support for AES CTR mode in OpenSSL
# 0.9.8. It can be removed when we drop 0.9.8 support (RHEL 5
# extended life ends 2020).
return _AESCTRCipherContext(self, cipher, mode)
else:
return _CipherContext(self, cipher, mode, _CipherContext._DECRYPT)
def pbkdf2_hmac_supported(self, algorithm):
if self._lib.Cryptography_HAS_PBKDF2_HMAC:
return self.hmac_supported(algorithm)
else:
# OpenSSL < 1.0.0 has an explicit PBKDF2-HMAC-SHA1 function,
# so if the PBKDF2_HMAC function is missing we only support
# SHA1 via PBKDF2_HMAC_SHA1.
return isinstance(algorithm, hashes.SHA1)
def derive_pbkdf2_hmac(self, algorithm, length, salt, iterations,
key_material):
buf = self._ffi.new("char[]", length)
if self._lib.Cryptography_HAS_PBKDF2_HMAC:
evp_md = self._lib.EVP_get_digestbyname(
algorithm.name.encode("ascii"))
assert evp_md != self._ffi.NULL
res = self._lib.PKCS5_PBKDF2_HMAC(
key_material,
len(key_material),
salt,
len(salt),
iterations,
evp_md,
length,
buf
)
assert res == 1
else:
if not isinstance(algorithm, hashes.SHA1):
raise UnsupportedAlgorithm(
"This version of OpenSSL only supports PBKDF2HMAC with "
"SHA1.",
_Reasons.UNSUPPORTED_HASH
)
res = self._lib.PKCS5_PBKDF2_HMAC_SHA1(
key_material,
len(key_material),
salt,
len(salt),
iterations,
length,
buf
)
assert res == 1
return self._ffi.buffer(buf)[:]
def _err_string(self, code):
err_buf = self._ffi.new("char[]", 256)
self._lib.ERR_error_string_n(code, err_buf, 256)
return self._ffi.string(err_buf, 256)[:]
def _consume_errors(self):
errors = []
while True:
code = self._lib.ERR_get_error()
if code == 0:
break
lib = self._lib.ERR_GET_LIB(code)
func = self._lib.ERR_GET_FUNC(code)
reason = self._lib.ERR_GET_REASON(code)
errors.append(_OpenSSLError(code, lib, func, reason))
return errors
def _unknown_error(self, error):
return InternalError(
"Unknown error code {0} from OpenSSL, "
"you should probably file a bug. {1}.".format(
error.code, self._err_string(error.code)
)
)
def _bn_to_int(self, bn):
assert bn != self._ffi.NULL
if six.PY3:
# Python 3 has constant time from_bytes, so use that.
bn_num_bytes = (self._lib.BN_num_bits(bn) + 7) // 8
bin_ptr = self._ffi.new("unsigned char[]", bn_num_bytes)
bin_len = self._lib.BN_bn2bin(bn, bin_ptr)
# A zero length means the BN has value 0
assert bin_len >= 0
assert bin_ptr != self._ffi.NULL
return int.from_bytes(self._ffi.buffer(bin_ptr)[:bin_len], "big")
else:
# Under Python 2 the best we can do is hex()
hex_cdata = self._lib.BN_bn2hex(bn)
assert hex_cdata != self._ffi.NULL
hex_str = self._ffi.string(hex_cdata)
self._lib.OPENSSL_free(hex_cdata)
return int(hex_str, 16)
def _int_to_bn(self, num, bn=None):
"""
Converts a python integer to a BIGNUM. The returned BIGNUM will not
be garbage collected (to support adding them to structs that take
ownership of the object). Be sure to register it for GC if it will
be discarded after use.
"""
assert bn is None or bn != self._ffi.NULL
if bn is None:
bn = self._ffi.NULL
if six.PY3:
# Python 3 has constant time to_bytes, so use that.
binary = num.to_bytes(int(num.bit_length() / 8.0 + 1), "big")
bn_ptr = self._lib.BN_bin2bn(binary, len(binary), bn)
assert bn_ptr != self._ffi.NULL
return bn_ptr
else:
# Under Python 2 the best we can do is hex()
hex_num = hex(num).rstrip("L").lstrip("0x").encode("ascii") or b"0"
bn_ptr = self._ffi.new("BIGNUM **")
bn_ptr[0] = bn
res = self._lib.BN_hex2bn(bn_ptr, hex_num)
assert res != 0
assert bn_ptr[0] != self._ffi.NULL
return bn_ptr[0]
def generate_rsa_private_key(self, public_exponent, key_size):
rsa._verify_rsa_parameters(public_exponent, key_size)
rsa_cdata = self._lib.RSA_new()
assert rsa_cdata != self._ffi.NULL
rsa_cdata = self._ffi.gc(rsa_cdata, self._lib.RSA_free)
bn = self._int_to_bn(public_exponent)
bn = self._ffi.gc(bn, self._lib.BN_free)
res = self._lib.RSA_generate_key_ex(
rsa_cdata, key_size, bn, self._ffi.NULL
)
assert res == 1
evp_pkey = self._rsa_cdata_to_evp_pkey(rsa_cdata)
return _RSAPrivateKey(self, rsa_cdata, evp_pkey)
def generate_rsa_parameters_supported(self, public_exponent, key_size):
return (public_exponent >= 3 and public_exponent & 1 != 0 and
key_size >= 512)
def load_rsa_private_numbers(self, numbers):
rsa._check_private_key_components(
numbers.p,
numbers.q,
numbers.d,
numbers.dmp1,
numbers.dmq1,
numbers.iqmp,
numbers.public_numbers.e,
numbers.public_numbers.n
)
rsa_cdata = self._lib.RSA_new()
assert rsa_cdata != self._ffi.NULL
rsa_cdata = self._ffi.gc(rsa_cdata, self._lib.RSA_free)
rsa_cdata.p = self._int_to_bn(numbers.p)
rsa_cdata.q = self._int_to_bn(numbers.q)
rsa_cdata.d = self._int_to_bn(numbers.d)
rsa_cdata.dmp1 = self._int_to_bn(numbers.dmp1)
rsa_cdata.dmq1 = self._int_to_bn(numbers.dmq1)
rsa_cdata.iqmp = self._int_to_bn(numbers.iqmp)
rsa_cdata.e = self._int_to_bn(numbers.public_numbers.e)
rsa_cdata.n = self._int_to_bn(numbers.public_numbers.n)
res = self._lib.RSA_blinding_on(rsa_cdata, self._ffi.NULL)
assert res == 1
evp_pkey = self._rsa_cdata_to_evp_pkey(rsa_cdata)
return _RSAPrivateKey(self, rsa_cdata, evp_pkey)
def load_rsa_public_numbers(self, numbers):
rsa._check_public_key_components(numbers.e, numbers.n)
rsa_cdata = self._lib.RSA_new()
assert rsa_cdata != self._ffi.NULL
rsa_cdata = self._ffi.gc(rsa_cdata, self._lib.RSA_free)
rsa_cdata.e = self._int_to_bn(numbers.e)
rsa_cdata.n = self._int_to_bn(numbers.n)
res = self._lib.RSA_blinding_on(rsa_cdata, self._ffi.NULL)
assert res == 1
evp_pkey = self._rsa_cdata_to_evp_pkey(rsa_cdata)
return _RSAPublicKey(self, rsa_cdata, evp_pkey)
def _rsa_cdata_to_evp_pkey(self, rsa_cdata):
evp_pkey = self._lib.EVP_PKEY_new()
assert evp_pkey != self._ffi.NULL
evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free)
res = self._lib.EVP_PKEY_set1_RSA(evp_pkey, rsa_cdata)
assert res == 1
return evp_pkey
def _bytes_to_bio(self, data):
"""
Return a _MemoryBIO namedtuple of (BIO, char*).
The char* is the storage for the BIO and it must stay alive until the
BIO is finished with.
"""
data_char_p = self._ffi.new("char[]", data)
bio = self._lib.BIO_new_mem_buf(
data_char_p, len(data)
)
assert bio != self._ffi.NULL
return _MemoryBIO(self._ffi.gc(bio, self._lib.BIO_free), data_char_p)
def _create_mem_bio(self):
"""
Creates an empty memory BIO.
"""
bio_method = self._lib.BIO_s_mem()
assert bio_method != self._ffi.NULL
bio = self._lib.BIO_new(bio_method)
assert bio != self._ffi.NULL
bio = self._ffi.gc(bio, self._lib.BIO_free)
return bio
def _read_mem_bio(self, bio):
"""
Reads a memory BIO. This only works on memory BIOs.
"""
buf = self._ffi.new("char **")
buf_len = self._lib.BIO_get_mem_data(bio, buf)
assert buf_len > 0
assert buf[0] != self._ffi.NULL
bio_data = self._ffi.buffer(buf[0], buf_len)[:]
return bio_data
def _evp_pkey_to_private_key(self, evp_pkey):
"""
Return the appropriate type of PrivateKey given an evp_pkey cdata
pointer.
"""
key_type = evp_pkey.type
if key_type == self._lib.EVP_PKEY_RSA:
rsa_cdata = self._lib.EVP_PKEY_get1_RSA(evp_pkey)
assert rsa_cdata != self._ffi.NULL
rsa_cdata = self._ffi.gc(rsa_cdata, self._lib.RSA_free)
return _RSAPrivateKey(self, rsa_cdata, evp_pkey)
elif key_type == self._lib.EVP_PKEY_DSA:
dsa_cdata = self._lib.EVP_PKEY_get1_DSA(evp_pkey)
assert dsa_cdata != self._ffi.NULL
dsa_cdata = self._ffi.gc(dsa_cdata, self._lib.DSA_free)
return _DSAPrivateKey(self, dsa_cdata, evp_pkey)
elif (self._lib.Cryptography_HAS_EC == 1 and
key_type == self._lib.EVP_PKEY_EC):
ec_cdata = self._lib.EVP_PKEY_get1_EC_KEY(evp_pkey)
assert ec_cdata != self._ffi.NULL
ec_cdata = self._ffi.gc(ec_cdata, self._lib.EC_KEY_free)
return _EllipticCurvePrivateKey(self, ec_cdata, evp_pkey)
else:
raise UnsupportedAlgorithm("Unsupported key type.")
def _evp_pkey_to_public_key(self, evp_pkey):
"""
Return the appropriate type of PublicKey given an evp_pkey cdata
pointer.
"""
key_type = evp_pkey.type
if key_type == self._lib.EVP_PKEY_RSA:
rsa_cdata = self._lib.EVP_PKEY_get1_RSA(evp_pkey)
assert rsa_cdata != self._ffi.NULL
rsa_cdata = self._ffi.gc(rsa_cdata, self._lib.RSA_free)
return _RSAPublicKey(self, rsa_cdata, evp_pkey)
elif key_type == self._lib.EVP_PKEY_DSA:
dsa_cdata = self._lib.EVP_PKEY_get1_DSA(evp_pkey)
assert dsa_cdata != self._ffi.NULL
dsa_cdata = self._ffi.gc(dsa_cdata, self._lib.DSA_free)
return _DSAPublicKey(self, dsa_cdata, evp_pkey)
elif (self._lib.Cryptography_HAS_EC == 1 and
key_type == self._lib.EVP_PKEY_EC):
ec_cdata = self._lib.EVP_PKEY_get1_EC_KEY(evp_pkey)
assert ec_cdata != self._ffi.NULL
ec_cdata = self._ffi.gc(ec_cdata, self._lib.EC_KEY_free)
return _EllipticCurvePublicKey(self, ec_cdata, evp_pkey)
else:
raise UnsupportedAlgorithm("Unsupported key type.")
def _pem_password_cb(self, password):
"""
Generate a pem_password_cb function pointer that copied the password to
OpenSSL as required and returns the number of bytes copied.
typedef int pem_password_cb(char *buf, int size,
int rwflag, void *userdata);
Useful for decrypting PKCS8 files and so on.
Returns a tuple of (cdata function pointer, callback function).
"""
def pem_password_cb(buf, size, writing, userdata):
pem_password_cb.called += 1
if not password:
pem_password_cb.exception = TypeError(
"Password was not given but private key is encrypted."
)
return 0
elif len(password) < size:
pw_buf = self._ffi.buffer(buf, size)
pw_buf[:len(password)] = password
return len(password)
else:
pem_password_cb.exception = ValueError(
"Passwords longer than {0} bytes are not supported "
"by this backend.".format(size - 1)
)
return 0
pem_password_cb.called = 0
pem_password_cb.exception = None
return (
self._ffi.callback("int (char *, int, int, void *)",
pem_password_cb),
pem_password_cb
)
def _mgf1_hash_supported(self, algorithm):
if self._lib.Cryptography_HAS_MGF1_MD:
return self.hash_supported(algorithm)
else:
return isinstance(algorithm, hashes.SHA1)
def rsa_padding_supported(self, padding):
if isinstance(padding, PKCS1v15):
return True
elif isinstance(padding, PSS) and isinstance(padding._mgf, MGF1):
return self._mgf1_hash_supported(padding._mgf._algorithm)
elif isinstance(padding, OAEP) and isinstance(padding._mgf, MGF1):
return isinstance(padding._mgf._algorithm, hashes.SHA1)
else:
return False
def generate_dsa_parameters(self, key_size):
if key_size not in (1024, 2048, 3072):
raise ValueError("Key size must be 1024 or 2048 or 3072 bits.")
if (self._lib.OPENSSL_VERSION_NUMBER < 0x1000000f and
key_size > 1024):
raise ValueError(
"Key size must be 1024 because OpenSSL < 1.0.0 doesn't "
"support larger key sizes.")
ctx = self._lib.DSA_new()
assert ctx != self._ffi.NULL
ctx = self._ffi.gc(ctx, self._lib.DSA_free)
res = self._lib.DSA_generate_parameters_ex(
ctx, key_size, self._ffi.NULL, 0,
self._ffi.NULL, self._ffi.NULL, self._ffi.NULL
)
assert res == 1
return _DSAParameters(self, ctx)
def generate_dsa_private_key(self, parameters):
ctx = self._lib.DSA_new()
assert ctx != self._ffi.NULL
ctx = self._ffi.gc(ctx, self._lib.DSA_free)
ctx.p = self._lib.BN_dup(parameters._dsa_cdata.p)
ctx.q = self._lib.BN_dup(parameters._dsa_cdata.q)
ctx.g = self._lib.BN_dup(parameters._dsa_cdata.g)
self._lib.DSA_generate_key(ctx)
evp_pkey = self._dsa_cdata_to_evp_pkey(ctx)
return _DSAPrivateKey(self, ctx, evp_pkey)
def generate_dsa_private_key_and_parameters(self, key_size):
parameters = self.generate_dsa_parameters(key_size)
return self.generate_dsa_private_key(parameters)
def load_dsa_private_numbers(self, numbers):
dsa._check_dsa_private_numbers(numbers)
parameter_numbers = numbers.public_numbers.parameter_numbers
dsa_cdata = self._lib.DSA_new()
assert dsa_cdata != self._ffi.NULL
dsa_cdata = self._ffi.gc(dsa_cdata, self._lib.DSA_free)
dsa_cdata.p = self._int_to_bn(parameter_numbers.p)
dsa_cdata.q = self._int_to_bn(parameter_numbers.q)
dsa_cdata.g = self._int_to_bn(parameter_numbers.g)
dsa_cdata.pub_key = self._int_to_bn(numbers.public_numbers.y)
dsa_cdata.priv_key = self._int_to_bn(numbers.x)
evp_pkey = self._dsa_cdata_to_evp_pkey(dsa_cdata)
return _DSAPrivateKey(self, dsa_cdata, evp_pkey)
def load_dsa_public_numbers(self, numbers):
dsa._check_dsa_parameters(numbers.parameter_numbers)
dsa_cdata = self._lib.DSA_new()
assert dsa_cdata != self._ffi.NULL
dsa_cdata = self._ffi.gc(dsa_cdata, self._lib.DSA_free)
dsa_cdata.p = self._int_to_bn(numbers.parameter_numbers.p)
dsa_cdata.q = self._int_to_bn(numbers.parameter_numbers.q)
dsa_cdata.g = self._int_to_bn(numbers.parameter_numbers.g)
dsa_cdata.pub_key = self._int_to_bn(numbers.y)
evp_pkey = self._dsa_cdata_to_evp_pkey(dsa_cdata)
return _DSAPublicKey(self, dsa_cdata, evp_pkey)
def load_dsa_parameter_numbers(self, numbers):
dsa._check_dsa_parameters(numbers)
dsa_cdata = self._lib.DSA_new()
assert dsa_cdata != self._ffi.NULL
dsa_cdata = self._ffi.gc(dsa_cdata, self._lib.DSA_free)
dsa_cdata.p = self._int_to_bn(numbers.p)
dsa_cdata.q = self._int_to_bn(numbers.q)
dsa_cdata.g = self._int_to_bn(numbers.g)
return _DSAParameters(self, dsa_cdata)
def _dsa_cdata_to_evp_pkey(self, dsa_cdata):
evp_pkey = self._lib.EVP_PKEY_new()
assert evp_pkey != self._ffi.NULL
evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free)
res = self._lib.EVP_PKEY_set1_DSA(evp_pkey, dsa_cdata)
assert res == 1
return evp_pkey
def dsa_hash_supported(self, algorithm):
if self._lib.OPENSSL_VERSION_NUMBER < 0x1000000f:
return isinstance(algorithm, hashes.SHA1)
else:
return self.hash_supported(algorithm)
def dsa_parameters_supported(self, p, q, g):
if self._lib.OPENSSL_VERSION_NUMBER < 0x1000000f:
return utils.bit_length(p) <= 1024 and utils.bit_length(q) <= 160
else:
return True
def cmac_algorithm_supported(self, algorithm):
return (
self._lib.Cryptography_HAS_CMAC == 1 and
self.cipher_supported(
algorithm, CBC(b"\x00" * algorithm.block_size)
)
)
def create_cmac_ctx(self, algorithm):
return _CMACContext(self, algorithm)
def create_x509_csr(self, builder, private_key, algorithm):
if not isinstance(algorithm, hashes.HashAlgorithm):
raise TypeError('Algorithm must be a registered hash algorithm.')
if self._lib.OPENSSL_VERSION_NUMBER <= 0x10001000:
if isinstance(private_key, _DSAPrivateKey):
raise NotImplementedError(
"Certificate signing requests aren't implemented for DSA"
" keys on OpenSSL versions less than 1.0.1."
)
if isinstance(private_key, _EllipticCurvePrivateKey):
raise NotImplementedError(
"Certificate signing requests aren't implemented for EC"
" keys on OpenSSL versions less than 1.0.1."
)
# Resolve the signature algorithm.
evp_md = self._lib.EVP_get_digestbyname(
algorithm.name.encode('ascii')
)
assert evp_md != self._ffi.NULL
# Create an empty request.
x509_req = self._lib.X509_REQ_new()
assert x509_req != self._ffi.NULL
x509_req = self._ffi.gc(x509_req, self._lib.X509_REQ_free)
# Set x509 version.
res = self._lib.X509_REQ_set_version(x509_req, x509.Version.v1.value)
assert res == 1
# Set subject name.
res = self._lib.X509_REQ_set_subject_name(
x509_req, _encode_name_gc(self, builder._subject_name)
)
assert res == 1
# Set subject public key.
public_key = private_key.public_key()
res = self._lib.X509_REQ_set_pubkey(
x509_req, public_key._evp_pkey
)
assert res == 1
# Add extensions.
extensions = self._lib.sk_X509_EXTENSION_new_null()
assert extensions != self._ffi.NULL
extensions = self._ffi.gc(
extensions,
self._lib.sk_X509_EXTENSION_free,
)
for extension in builder._extensions:
if isinstance(extension.value, x509.BasicConstraints):
pp, r = _encode_basic_constraints(self, extension.value)
elif isinstance(extension.value, x509.SubjectAlternativeName):
pp, r = _encode_subject_alt_name(self, extension.value)
else:
raise NotImplementedError('Extension not yet supported.')
obj = _txt2obj(self, extension.oid.dotted_string)
extension = self._lib.X509_EXTENSION_create_by_OBJ(
self._ffi.NULL,
obj,
1 if extension.critical else 0,
_encode_asn1_str_gc(self, pp[0], r),
)
assert extension != self._ffi.NULL
res = self._lib.sk_X509_EXTENSION_push(extensions, extension)
assert res == 1
res = self._lib.X509_REQ_add_extensions(x509_req, extensions)
assert res == 1
# Sign the request using the requester's private key.
res = self._lib.X509_REQ_sign(
x509_req, private_key._evp_pkey, evp_md
)
assert res > 0
return _CertificateSigningRequest(self, x509_req)
def sign_x509_certificate(self, builder, private_key, algorithm):
# TODO: check type of private key parameter.
if not isinstance(builder, x509.CertificateBuilder):
raise TypeError('Builder type mismatch.')
if not isinstance(algorithm, hashes.HashAlgorithm):
raise TypeError('Algorithm must be a registered hash algorithm.')
# Resolve the signature algorithm.
evp_md = self._lib.EVP_get_digestbyname(
algorithm.name.encode('ascii')
)
assert evp_md != self._ffi.NULL
# Create an empty certificate.
x509_cert = self._lib.X509_new()
x509_cert = self._ffi.gc(x509_cert, backend._lib.X509_free)
# Set the x509 version.
res = self._lib.X509_set_version(x509_cert, builder._version.value)
assert res == 1
# Set the subject's name.
res = self._lib.X509_set_subject_name(
x509_cert, _encode_name(self, list(builder._subject_name))
)
assert res == 1
# Set the subject's public key.
res = self._lib.X509_set_pubkey(
x509_cert, builder._public_key._evp_pkey
)
assert res == 1
# Set the certificate serial number.
serial_number = _make_asn1_int(self, builder._serial_number)
self._lib.X509_set_serialNumber(x509_cert, serial_number)
# Set the "not before" time.
res = self._lib.ASN1_TIME_set(
self._lib.X509_get_notBefore(x509_cert),
calendar.timegm(builder._not_valid_before.timetuple())
)
assert res != self._ffi.NULL
# Set the "not after" time.
res = self._lib.ASN1_TIME_set(
self._lib.X509_get_notAfter(x509_cert),
calendar.timegm(builder._not_valid_after.timetuple())
)
assert res != self._ffi.NULL
# Add extensions.
for i, extension in enumerate(builder._extensions):
if isinstance(extension.value, x509.BasicConstraints):
extension = _encode_basic_constraints(
self,
extension.value.ca,
extension.value.path_length,
extension.critical
)
else:
raise ValueError('Extension not yet supported.')
res = self._lib.X509_add_ext(x509_cert, extension, i)
assert res == 1
# Set the issuer name.
res = self._lib.X509_set_issuer_name(
x509_cert, _encode_name(self, list(builder._issuer_name))
)
assert res == 1
# Sign the certificate with the issuer's private key.
res = self._lib.X509_sign(
x509_cert, private_key._evp_pkey, evp_md
)
assert res > 0
return _Certificate(self, x509_cert)
def load_pem_private_key(self, data, password):
return self._load_key(
self._lib.PEM_read_bio_PrivateKey,
self._evp_pkey_to_private_key,
data,
password,
)
def load_pem_public_key(self, data):
mem_bio = self._bytes_to_bio(data)
evp_pkey = self._lib.PEM_read_bio_PUBKEY(
mem_bio.bio, self._ffi.NULL, self._ffi.NULL, self._ffi.NULL
)
if evp_pkey != self._ffi.NULL:
evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free)
return self._evp_pkey_to_public_key(evp_pkey)
else:
# It's not a (RSA/DSA/ECDSA) subjectPublicKeyInfo, but we still
# need to check to see if it is a pure PKCS1 RSA public key (not
# embedded in a subjectPublicKeyInfo)
self._consume_errors()
res = self._lib.BIO_reset(mem_bio.bio)
assert res == 1
rsa_cdata = self._lib.PEM_read_bio_RSAPublicKey(
mem_bio.bio, self._ffi.NULL, self._ffi.NULL, self._ffi.NULL
)
if rsa_cdata != self._ffi.NULL:
rsa_cdata = self._ffi.gc(rsa_cdata, self._lib.RSA_free)
evp_pkey = self._rsa_cdata_to_evp_pkey(rsa_cdata)
return _RSAPublicKey(self, rsa_cdata, evp_pkey)
else:
self._handle_key_loading_error()
def load_der_private_key(self, data, password):
# OpenSSL has a function called d2i_AutoPrivateKey that can simplify
# this. Unfortunately it doesn't properly support PKCS8 on OpenSSL
# 0.9.8 so we can't use it. Instead we sequentially try to load it 3
# different ways. First we'll try to load it as a traditional key
bio_data = self._bytes_to_bio(data)
key = self._evp_pkey_from_der_traditional_key(bio_data, password)
if not key:
# Okay so it's not a traditional key. Let's try
# PKCS8 unencrypted. OpenSSL 0.9.8 can't load unencrypted
# PKCS8 keys using d2i_PKCS8PrivateKey_bio so we do this instead.
# Reset the memory BIO so we can read the data again.
res = self._lib.BIO_reset(bio_data.bio)
assert res == 1
key = self._evp_pkey_from_der_unencrypted_pkcs8(bio_data, password)
if key:
return self._evp_pkey_to_private_key(key)
else:
# Finally we try to load it with the method that handles encrypted
# PKCS8 properly.
return self._load_key(
self._lib.d2i_PKCS8PrivateKey_bio,
self._evp_pkey_to_private_key,
data,
password,
)
def _evp_pkey_from_der_traditional_key(self, bio_data, password):
key = self._lib.d2i_PrivateKey_bio(bio_data.bio, self._ffi.NULL)
if key != self._ffi.NULL:
key = self._ffi.gc(key, self._lib.EVP_PKEY_free)
if password is not None:
raise TypeError(
"Password was given but private key is not encrypted."
)
return key
else:
self._consume_errors()
return None
def _evp_pkey_from_der_unencrypted_pkcs8(self, bio_data, password):
info = self._lib.d2i_PKCS8_PRIV_KEY_INFO_bio(
bio_data.bio, self._ffi.NULL
)
info = self._ffi.gc(info, self._lib.PKCS8_PRIV_KEY_INFO_free)
if info != self._ffi.NULL:
key = self._lib.EVP_PKCS82PKEY(info)
assert key != self._ffi.NULL
key = self._ffi.gc(key, self._lib.EVP_PKEY_free)
if password is not None:
raise TypeError(
"Password was given but private key is not encrypted."
)
return key
else:
self._consume_errors()
return None
def load_der_public_key(self, data):
mem_bio = self._bytes_to_bio(data)
evp_pkey = self._lib.d2i_PUBKEY_bio(mem_bio.bio, self._ffi.NULL)
if evp_pkey != self._ffi.NULL:
evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free)
return self._evp_pkey_to_public_key(evp_pkey)
else:
# It's not a (RSA/DSA/ECDSA) subjectPublicKeyInfo, but we still
# need to check to see if it is a pure PKCS1 RSA public key (not
# embedded in a subjectPublicKeyInfo)
self._consume_errors()
res = self._lib.BIO_reset(mem_bio.bio)
assert res == 1
rsa_cdata = self._lib.d2i_RSAPublicKey_bio(
mem_bio.bio, self._ffi.NULL
)
if rsa_cdata != self._ffi.NULL:
rsa_cdata = self._ffi.gc(rsa_cdata, self._lib.RSA_free)
evp_pkey = self._rsa_cdata_to_evp_pkey(rsa_cdata)
return _RSAPublicKey(self, rsa_cdata, evp_pkey)
else:
self._handle_key_loading_error()
def load_pem_x509_certificate(self, data):
mem_bio = self._bytes_to_bio(data)
x509 = self._lib.PEM_read_bio_X509(
mem_bio.bio, self._ffi.NULL, self._ffi.NULL, self._ffi.NULL
)
if x509 == self._ffi.NULL:
self._consume_errors()
raise ValueError("Unable to load certificate")
x509 = self._ffi.gc(x509, self._lib.X509_free)
return _Certificate(self, x509)
def load_der_x509_certificate(self, data):
mem_bio = self._bytes_to_bio(data)
x509 = self._lib.d2i_X509_bio(mem_bio.bio, self._ffi.NULL)
if x509 == self._ffi.NULL:
self._consume_errors()
raise ValueError("Unable to load certificate")
x509 = self._ffi.gc(x509, self._lib.X509_free)
return _Certificate(self, x509)
def load_pem_x509_csr(self, data):
mem_bio = self._bytes_to_bio(data)
x509_req = self._lib.PEM_read_bio_X509_REQ(
mem_bio.bio, self._ffi.NULL, self._ffi.NULL, self._ffi.NULL
)
if x509_req == self._ffi.NULL:
self._consume_errors()
raise ValueError("Unable to load request")
x509_req = self._ffi.gc(x509_req, self._lib.X509_REQ_free)
return _CertificateSigningRequest(self, x509_req)
def load_der_x509_csr(self, data):
mem_bio = self._bytes_to_bio(data)
x509_req = self._lib.d2i_X509_REQ_bio(mem_bio.bio, self._ffi.NULL)
if x509_req == self._ffi.NULL:
self._consume_errors()
raise ValueError("Unable to load request")
x509_req = self._ffi.gc(x509_req, self._lib.X509_REQ_free)
return _CertificateSigningRequest(self, x509_req)
def _load_key(self, openssl_read_func, convert_func, data, password):
mem_bio = self._bytes_to_bio(data)
password_callback, password_func = self._pem_password_cb(password)
evp_pkey = openssl_read_func(
mem_bio.bio,
self._ffi.NULL,
password_callback,
self._ffi.NULL
)
if evp_pkey == self._ffi.NULL:
if password_func.exception is not None:
errors = self._consume_errors()
assert errors
raise password_func.exception
else:
self._handle_key_loading_error()
evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free)
if password is not None and password_func.called == 0:
raise TypeError(
"Password was given but private key is not encrypted.")
assert (
(password is not None and password_func.called == 1) or
password is None
)
return convert_func(evp_pkey)
def _handle_key_loading_error(self):
errors = self._consume_errors()
if not errors:
raise ValueError("Could not unserialize key data.")
elif errors[0][1:] in (
(
self._lib.ERR_LIB_EVP,
self._lib.EVP_F_EVP_DECRYPTFINAL_EX,
self._lib.EVP_R_BAD_DECRYPT
),
(
self._lib.ERR_LIB_PKCS12,
self._lib.PKCS12_F_PKCS12_PBE_CRYPT,
self._lib.PKCS12_R_PKCS12_CIPHERFINAL_ERROR,
)
):
raise ValueError("Bad decrypt. Incorrect password?")
elif errors[0][1:] in (
(
self._lib.ERR_LIB_PEM,
self._lib.PEM_F_PEM_GET_EVP_CIPHER_INFO,
self._lib.PEM_R_UNSUPPORTED_ENCRYPTION
),
(
self._lib.ERR_LIB_EVP,
self._lib.EVP_F_EVP_PBE_CIPHERINIT,
self._lib.EVP_R_UNKNOWN_PBE_ALGORITHM
)
):
raise UnsupportedAlgorithm(
"PEM data is encrypted with an unsupported cipher",
_Reasons.UNSUPPORTED_CIPHER
)
elif any(
error[1:] == (
self._lib.ERR_LIB_EVP,
self._lib.EVP_F_EVP_PKCS82PKEY,
self._lib.EVP_R_UNSUPPORTED_PRIVATE_KEY_ALGORITHM
)
for error in errors
):
raise UnsupportedAlgorithm(
"Unsupported public key algorithm.",
_Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM
)
else:
assert errors[0][1] in (
self._lib.ERR_LIB_EVP,
self._lib.ERR_LIB_PEM,
self._lib.ERR_LIB_ASN1,
)
raise ValueError("Could not unserialize key data.")
def elliptic_curve_supported(self, curve):
if self._lib.Cryptography_HAS_EC != 1:
return False
try:
curve_nid = self._elliptic_curve_to_nid(curve)
except UnsupportedAlgorithm:
curve_nid = self._lib.NID_undef
ctx = self._lib.EC_GROUP_new_by_curve_name(curve_nid)
if ctx == self._ffi.NULL:
errors = self._consume_errors()
assert (
curve_nid == self._lib.NID_undef or
errors[0][1:] == (
self._lib.ERR_LIB_EC,
self._lib.EC_F_EC_GROUP_NEW_BY_CURVE_NAME,
self._lib.EC_R_UNKNOWN_GROUP
)
)
return False
else:
assert curve_nid != self._lib.NID_undef
self._lib.EC_GROUP_free(ctx)
return True
def elliptic_curve_signature_algorithm_supported(
self, signature_algorithm, curve
):
if self._lib.Cryptography_HAS_EC != 1:
return False
# We only support ECDSA right now.
if not isinstance(signature_algorithm, ec.ECDSA):
return False
# Before 0.9.8m OpenSSL can't cope with digests longer than the curve.
if (
self._lib.OPENSSL_VERSION_NUMBER < 0x009080df and
curve.key_size < signature_algorithm.algorithm.digest_size * 8
):
return False
return self.elliptic_curve_supported(curve)
def generate_elliptic_curve_private_key(self, curve):
"""
Generate a new private key on the named curve.
"""
if self.elliptic_curve_supported(curve):
curve_nid = self._elliptic_curve_to_nid(curve)
ec_cdata = self._lib.EC_KEY_new_by_curve_name(curve_nid)
assert ec_cdata != self._ffi.NULL
ec_cdata = self._ffi.gc(ec_cdata, self._lib.EC_KEY_free)
res = self._lib.EC_KEY_generate_key(ec_cdata)
assert res == 1
res = self._lib.EC_KEY_check_key(ec_cdata)
assert res == 1
evp_pkey = self._ec_cdata_to_evp_pkey(ec_cdata)
return _EllipticCurvePrivateKey(self, ec_cdata, evp_pkey)
else:
raise UnsupportedAlgorithm(
"Backend object does not support {0}.".format(curve.name),
_Reasons.UNSUPPORTED_ELLIPTIC_CURVE
)
def load_elliptic_curve_private_numbers(self, numbers):
public = numbers.public_numbers
curve_nid = self._elliptic_curve_to_nid(public.curve)
ec_cdata = self._lib.EC_KEY_new_by_curve_name(curve_nid)
assert ec_cdata != self._ffi.NULL
ec_cdata = self._ffi.gc(ec_cdata, self._lib.EC_KEY_free)
ec_cdata = self._ec_key_set_public_key_affine_coordinates(
ec_cdata, public.x, public.y)
res = self._lib.EC_KEY_set_private_key(
ec_cdata, self._int_to_bn(numbers.private_value))
assert res == 1
evp_pkey = self._ec_cdata_to_evp_pkey(ec_cdata)
return _EllipticCurvePrivateKey(self, ec_cdata, evp_pkey)
def load_elliptic_curve_public_numbers(self, numbers):
curve_nid = self._elliptic_curve_to_nid(numbers.curve)
ec_cdata = self._lib.EC_KEY_new_by_curve_name(curve_nid)
assert ec_cdata != self._ffi.NULL
ec_cdata = self._ffi.gc(ec_cdata, self._lib.EC_KEY_free)
ec_cdata = self._ec_key_set_public_key_affine_coordinates(
ec_cdata, numbers.x, numbers.y)
evp_pkey = self._ec_cdata_to_evp_pkey(ec_cdata)
return _EllipticCurvePublicKey(self, ec_cdata, evp_pkey)
def _ec_cdata_to_evp_pkey(self, ec_cdata):
evp_pkey = self._lib.EVP_PKEY_new()
assert evp_pkey != self._ffi.NULL
evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free)
res = self._lib.EVP_PKEY_set1_EC_KEY(evp_pkey, ec_cdata)
assert res == 1
return evp_pkey
def _elliptic_curve_to_nid(self, curve):
"""
Get the NID for a curve name.
"""
curve_aliases = {
"secp192r1": "prime192v1",
"secp256r1": "prime256v1"
}
curve_name = curve_aliases.get(curve.name, curve.name)
curve_nid = self._lib.OBJ_sn2nid(curve_name.encode())
if curve_nid == self._lib.NID_undef:
raise UnsupportedAlgorithm(
"{0} is not a supported elliptic curve".format(curve.name),
_Reasons.UNSUPPORTED_ELLIPTIC_CURVE
)
return curve_nid
@contextmanager
def _tmp_bn_ctx(self):
bn_ctx = self._lib.BN_CTX_new()
assert bn_ctx != self._ffi.NULL
bn_ctx = self._ffi.gc(bn_ctx, self._lib.BN_CTX_free)
self._lib.BN_CTX_start(bn_ctx)
try:
yield bn_ctx
finally:
self._lib.BN_CTX_end(bn_ctx)
def _ec_key_determine_group_get_set_funcs(self, ctx):
"""
Given an EC_KEY determine the group and what methods are required to
get/set point coordinates.
"""
assert ctx != self._ffi.NULL
nid_two_field = self._lib.OBJ_sn2nid(b"characteristic-two-field")
assert nid_two_field != self._lib.NID_undef
group = self._lib.EC_KEY_get0_group(ctx)
assert group != self._ffi.NULL
method = self._lib.EC_GROUP_method_of(group)
assert method != self._ffi.NULL
nid = self._lib.EC_METHOD_get_field_type(method)
assert nid != self._lib.NID_undef
if nid == nid_two_field and self._lib.Cryptography_HAS_EC2M:
set_func = self._lib.EC_POINT_set_affine_coordinates_GF2m
get_func = self._lib.EC_POINT_get_affine_coordinates_GF2m
else:
set_func = self._lib.EC_POINT_set_affine_coordinates_GFp
get_func = self._lib.EC_POINT_get_affine_coordinates_GFp
assert set_func and get_func
return set_func, get_func, group
def _ec_key_set_public_key_affine_coordinates(self, ctx, x, y):
"""
This is a port of EC_KEY_set_public_key_affine_coordinates that was
added in 1.0.1.
Sets the public key point in the EC_KEY context to the affine x and y
values.
"""
if x < 0 or y < 0:
raise ValueError(
"Invalid EC key. Both x and y must be non-negative."
)
set_func, get_func, group = (
self._ec_key_determine_group_get_set_funcs(ctx)
)
point = self._lib.EC_POINT_new(group)
assert point != self._ffi.NULL
point = self._ffi.gc(point, self._lib.EC_POINT_free)
bn_x = self._int_to_bn(x)
bn_y = self._int_to_bn(y)
with self._tmp_bn_ctx() as bn_ctx:
check_x = self._lib.BN_CTX_get(bn_ctx)
check_y = self._lib.BN_CTX_get(bn_ctx)
res = set_func(group, point, bn_x, bn_y, bn_ctx)
assert res == 1
res = get_func(group, point, check_x, check_y, bn_ctx)
assert res == 1
res = self._lib.BN_cmp(bn_x, check_x)
assert res == 0
res = self._lib.BN_cmp(bn_y, check_y)
assert res == 0
res = self._lib.EC_KEY_set_public_key(ctx, point)
assert res == 1
res = self._lib.EC_KEY_check_key(ctx)
if res != 1:
self._consume_errors()
raise ValueError("Invalid EC key.")
return ctx
def _private_key_bytes(self, encoding, format, encryption_algorithm,
evp_pkey, cdata):
if not isinstance(format, serialization.PrivateFormat):
raise TypeError(
"format must be an item from the PrivateFormat enum"
)
if not isinstance(encryption_algorithm,
serialization.KeySerializationEncryption):
raise TypeError(
"Encryption algorithm must be a KeySerializationEncryption "
"instance"
)
if isinstance(encryption_algorithm, serialization.NoEncryption):
password = b""
passlen = 0
evp_cipher = self._ffi.NULL
elif isinstance(encryption_algorithm,
serialization.BestAvailableEncryption):
# This is a curated value that we will update over time.
evp_cipher = self._lib.EVP_get_cipherbyname(
b"aes-256-cbc"
)
password = encryption_algorithm.password
passlen = len(password)
if passlen > 1023:
raise ValueError(
"Passwords longer than 1023 bytes are not supported by "
"this backend"
)
else:
raise ValueError("Unsupported encryption type")
if encoding is serialization.Encoding.PEM:
if format is serialization.PrivateFormat.PKCS8:
write_bio = self._lib.PEM_write_bio_PKCS8PrivateKey
key = evp_pkey
elif format is serialization.PrivateFormat.TraditionalOpenSSL:
if evp_pkey.type == self._lib.EVP_PKEY_RSA:
write_bio = self._lib.PEM_write_bio_RSAPrivateKey
elif evp_pkey.type == self._lib.EVP_PKEY_DSA:
write_bio = self._lib.PEM_write_bio_DSAPrivateKey
elif (self._lib.Cryptography_HAS_EC == 1 and
evp_pkey.type == self._lib.EVP_PKEY_EC):
write_bio = self._lib.PEM_write_bio_ECPrivateKey
key = cdata
elif encoding is serialization.Encoding.DER:
if format is serialization.PrivateFormat.TraditionalOpenSSL:
if not isinstance(
encryption_algorithm, serialization.NoEncryption
):
raise ValueError(
"Encryption is not supported for DER encoded "
"traditional OpenSSL keys"
)
return self._private_key_bytes_traditional_der(
evp_pkey.type, cdata
)
elif format is serialization.PrivateFormat.PKCS8:
write_bio = self._lib.i2d_PKCS8PrivateKey_bio
key = evp_pkey
else:
raise TypeError("encoding must be an item from the Encoding enum")
bio = self._create_mem_bio()
res = write_bio(
bio,
key,
evp_cipher,
password,
passlen,
self._ffi.NULL,
self._ffi.NULL
)
assert res == 1
return self._read_mem_bio(bio)
def _private_key_bytes_traditional_der(self, key_type, cdata):
if key_type == self._lib.EVP_PKEY_RSA:
write_bio = self._lib.i2d_RSAPrivateKey_bio
elif (self._lib.Cryptography_HAS_EC == 1 and
key_type == self._lib.EVP_PKEY_EC):
write_bio = self._lib.i2d_ECPrivateKey_bio
elif key_type == self._lib.EVP_PKEY_DSA:
write_bio = self._lib.i2d_DSAPrivateKey_bio
bio = self._create_mem_bio()
res = write_bio(bio, cdata)
assert res == 1
return self._read_mem_bio(bio)
def _public_key_bytes(self, encoding, format, evp_pkey, cdata):
if not isinstance(encoding, serialization.Encoding):
raise TypeError("encoding must be an item from the Encoding enum")
if format is serialization.PublicFormat.SubjectPublicKeyInfo:
if encoding is serialization.Encoding.PEM:
write_bio = self._lib.PEM_write_bio_PUBKEY
elif encoding is serialization.Encoding.DER:
write_bio = self._lib.i2d_PUBKEY_bio
key = evp_pkey
elif format is serialization.PublicFormat.PKCS1:
# Only RSA is supported here.
assert evp_pkey.type == self._lib.EVP_PKEY_RSA
if encoding is serialization.Encoding.PEM:
write_bio = self._lib.PEM_write_bio_RSAPublicKey
elif encoding is serialization.Encoding.DER:
write_bio = self._lib.i2d_RSAPublicKey_bio
key = cdata
else:
raise TypeError(
"format must be an item from the PublicFormat enum"
)
bio = self._create_mem_bio()
res = write_bio(bio, key)
assert res == 1
return self._read_mem_bio(bio)
class GetCipherByName(object):
def __init__(self, fmt):
self._fmt = fmt
def __call__(self, backend, cipher, mode):
cipher_name = self._fmt.format(cipher=cipher, mode=mode).lower()
return backend._lib.EVP_get_cipherbyname(cipher_name.encode("ascii"))
backend = Backend()
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