OwlCyberSecurity - MANAGER

Edit File: backend.py

# 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 collections import contextlib import itertools import warnings from contextlib import contextmanager import six from six.moves import range from cryptography import utils, x509 from cryptography.exceptions import UnsupportedAlgorithm, _Reasons from cryptography.hazmat._der import ( INTEGER, NULL, SEQUENCE, encode_der, encode_der_integer, ) from cryptography.hazmat.backends.interfaces import ( CMACBackend, CipherBackend, DERSerializationBackend, DHBackend, DSABackend, EllipticCurveBackend, HMACBackend, HashBackend, PBKDF2HMACBackend, PEMSerializationBackend, RSABackend, ScryptBackend, X509Backend, ) from cryptography.hazmat.backends.openssl import aead from cryptography.hazmat.backends.openssl.ciphers import _CipherContext from cryptography.hazmat.backends.openssl.cmac import _CMACContext from cryptography.hazmat.backends.openssl.decode_asn1 import ( _CRL_ENTRY_REASON_ENUM_TO_CODE, _CRL_EXTENSION_HANDLERS, _EXTENSION_HANDLERS_BASE, _EXTENSION_HANDLERS_SCT, _OCSP_BASICRESP_EXTENSION_HANDLERS, _OCSP_REQ_EXTENSION_HANDLERS, _OCSP_SINGLERESP_EXTENSION_HANDLERS_SCT, _REVOKED_EXTENSION_HANDLERS, _X509ExtensionParser, ) from cryptography.hazmat.backends.openssl.dh import ( _DHParameters, _DHPrivateKey, _DHPublicKey, _dh_params_dup, ) from cryptography.hazmat.backends.openssl.dsa import ( _DSAParameters, _DSAPrivateKey, _DSAPublicKey, ) from cryptography.hazmat.backends.openssl.ec import ( _EllipticCurvePrivateKey, _EllipticCurvePublicKey, ) from cryptography.hazmat.backends.openssl.ed25519 import ( _Ed25519PrivateKey, _Ed25519PublicKey, ) from cryptography.hazmat.backends.openssl.ed448 import ( _ED448_KEY_SIZE, _Ed448PrivateKey, _Ed448PublicKey, ) from cryptography.hazmat.backends.openssl.encode_asn1 import ( _CRL_ENTRY_EXTENSION_ENCODE_HANDLERS, _CRL_EXTENSION_ENCODE_HANDLERS, _EXTENSION_ENCODE_HANDLERS, _OCSP_BASICRESP_EXTENSION_ENCODE_HANDLERS, _OCSP_REQUEST_EXTENSION_ENCODE_HANDLERS, _encode_asn1_int_gc, _encode_asn1_str_gc, _encode_name_gc, _txt2obj_gc, ) from cryptography.hazmat.backends.openssl.hashes import _HashContext from cryptography.hazmat.backends.openssl.hmac import _HMACContext from cryptography.hazmat.backends.openssl.ocsp import ( _OCSPRequest, _OCSPResponse, ) from cryptography.hazmat.backends.openssl.poly1305 import ( _POLY1305_KEY_SIZE, _Poly1305Context, ) from cryptography.hazmat.backends.openssl.rsa import ( _RSAPrivateKey, _RSAPublicKey, ) from cryptography.hazmat.backends.openssl.x25519 import ( _X25519PrivateKey, _X25519PublicKey, ) from cryptography.hazmat.backends.openssl.x448 import ( _X448PrivateKey, _X448PublicKey, ) from cryptography.hazmat.backends.openssl.x509 import ( _Certificate, _CertificateRevocationList, _CertificateSigningRequest, _RevokedCertificate, ) from cryptography.hazmat.bindings.openssl import binding from cryptography.hazmat.primitives import hashes, serialization from cryptography.hazmat.primitives.asymmetric import ( dsa, ec, ed25519, ed448, rsa, ) from cryptography.hazmat.primitives.asymmetric.padding import ( MGF1, OAEP, PKCS1v15, PSS, ) from cryptography.hazmat.primitives.ciphers.algorithms import ( AES, ARC4, Blowfish, CAST5, Camellia, ChaCha20, IDEA, SEED, TripleDES, ) from cryptography.hazmat.primitives.ciphers.modes import ( CBC, CFB, CFB8, CTR, ECB, GCM, OFB, XTS, ) from cryptography.hazmat.primitives.kdf import scrypt from cryptography.hazmat.primitives.serialization import pkcs7, ssh from cryptography.x509 import ocsp _MemoryBIO = collections.namedtuple("_MemoryBIO", ["bio", "char_ptr"]) # Not actually supported, just used as a marker for some serialization tests. class _RC2(object): pass @utils.register_interface(CipherBackend) @utils.register_interface(CMACBackend) @utils.register_interface(DERSerializationBackend) @utils.register_interface(DHBackend) @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) @utils.register_interface_if( binding.Binding().lib.Cryptography_HAS_SCRYPT, ScryptBackend ) class Backend(object): """ OpenSSL API binding interfaces. """ name = "openssl" # FIPS has opinions about acceptable algorithms and key sizes, but the # disallowed algorithms are still present in OpenSSL. They just error if # you try to use them. To avoid that we allowlist the algorithms in # FIPS 140-3. This isn't ideal, but FIPS 140-3 is trash so here we are. _fips_aead = { b"aes-128-ccm", b"aes-192-ccm", b"aes-256-ccm", b"aes-128-gcm", b"aes-192-gcm", b"aes-256-gcm", } _fips_ciphers = (AES, TripleDES) _fips_hashes = ( hashes.SHA1, hashes.SHA224, hashes.SHA256, hashes.SHA384, hashes.SHA512, hashes.SHA512_224, hashes.SHA512_256, hashes.SHA3_224, hashes.SHA3_256, hashes.SHA3_384, hashes.SHA3_512, hashes.SHAKE128, hashes.SHAKE256, ) _fips_rsa_min_key_size = 2048 _fips_rsa_min_public_exponent = 65537 _fips_dsa_min_modulus = 1 << 2048 _fips_dh_min_key_size = 2048 _fips_dh_min_modulus = 1 << _fips_dh_min_key_size def __init__(self): self._binding = binding.Binding() self._ffi = self._binding.ffi self._lib = self._binding.lib self._fips_enabled = self._is_fips_enabled() self._cipher_registry = {} self._register_default_ciphers() self._register_x509_ext_parsers() self._register_x509_encoders() if self._fips_enabled and self._lib.CRYPTOGRAPHY_NEEDS_OSRANDOM_ENGINE: warnings.warn( "OpenSSL FIPS mode is enabled. Can't enable DRBG fork safety.", UserWarning, ) else: self.activate_osrandom_engine() self._dh_types = [self._lib.EVP_PKEY_DH] if self._lib.Cryptography_HAS_EVP_PKEY_DHX: self._dh_types.append(self._lib.EVP_PKEY_DHX) def openssl_assert(self, ok, errors=None): return binding._openssl_assert(self._lib, ok, errors=errors) def _is_fips_enabled(self): fips_mode = getattr(self._lib, "FIPS_mode", lambda: 0) mode = fips_mode() if mode == 0: # OpenSSL without FIPS pushes an error on the error stack self._lib.ERR_clear_error() return bool(mode) def activate_builtin_random(self): if self._lib.CRYPTOGRAPHY_NEEDS_OSRANDOM_ENGINE: # 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 built-in. res = self._lib.RAND_set_rand_method(self._ffi.NULL) self.openssl_assert(res == 1) # decrement the structural reference from get_default_RAND res = self._lib.ENGINE_finish(e) self.openssl_assert(res == 1) @contextlib.contextmanager def _get_osurandom_engine(self): # Fetches an engine by id and returns it. This creates a structural # reference. e = self._lib.ENGINE_by_id(self._lib.Cryptography_osrandom_engine_id) self.openssl_assert(e != self._ffi.NULL) # Initialize the engine for use. This adds a functional reference. res = self._lib.ENGINE_init(e) self.openssl_assert(res == 1) try: yield e finally: # Decrement the structural ref incremented by ENGINE_by_id. res = self._lib.ENGINE_free(e) self.openssl_assert(res == 1) # Decrement the functional ref incremented by ENGINE_init. res = self._lib.ENGINE_finish(e) self.openssl_assert(res == 1) def activate_osrandom_engine(self): if self._lib.CRYPTOGRAPHY_NEEDS_OSRANDOM_ENGINE: # Unregister and free the current engine. self.activate_builtin_random() with self._get_osurandom_engine() as e: # Set the engine as the default RAND provider. res = self._lib.ENGINE_set_default_RAND(e) self.openssl_assert(res == 1) # Reset the RNG to use the engine res = self._lib.RAND_set_rand_method(self._ffi.NULL) self.openssl_assert(res == 1) def osrandom_engine_implementation(self): buf = self._ffi.new("char[]", 64) with self._get_osurandom_engine() as e: res = self._lib.ENGINE_ctrl_cmd( e, b"get_implementation", len(buf), buf, self._ffi.NULL, 0 ) self.openssl_assert(res > 0) return self._ffi.string(buf).decode("ascii") 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 1.1.1d 10 Sep 2019 """ return self._ffi.string( self._lib.OpenSSL_version(self._lib.OPENSSL_VERSION) ).decode("ascii") def openssl_version_number(self): return self._lib.OpenSSL_version_num() def create_hmac_ctx(self, key, algorithm): return _HMACContext(self, key, algorithm) def _evp_md_from_algorithm(self, algorithm): if algorithm.name == "blake2b" or algorithm.name == "blake2s": alg = "{}{}".format( algorithm.name, algorithm.digest_size * 8 ).encode("ascii") else: alg = algorithm.name.encode("ascii") evp_md = self._lib.EVP_get_digestbyname(alg) return evp_md def _evp_md_non_null_from_algorithm(self, algorithm): evp_md = self._evp_md_from_algorithm(algorithm) self.openssl_assert(evp_md != self._ffi.NULL) return evp_md def hash_supported(self, algorithm): if self._fips_enabled and not isinstance(algorithm, self._fips_hashes): return False evp_md = self._evp_md_from_algorithm(algorithm) return evp_md != 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._fips_enabled and not isinstance(cipher, self._fips_ciphers): return False 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: {} {}.".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, GCM]: 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")) # We don't actually support RC2, this is just used by some tests. self.register_cipher_adapter(_RC2, type(None), GetCipherByName("rc2")) self.register_cipher_adapter( ChaCha20, type(None), GetCipherByName("chacha20") ) self.register_cipher_adapter(AES, XTS, _get_xts_cipher) def _register_x509_ext_parsers(self): ext_handlers = _EXTENSION_HANDLERS_BASE.copy() # All revoked extensions are valid single response extensions, see: # https://tools.ietf.org/html/rfc6960#section-4.4.5 singleresp_handlers = _REVOKED_EXTENSION_HANDLERS.copy() if self._lib.Cryptography_HAS_SCT: ext_handlers.update(_EXTENSION_HANDLERS_SCT) singleresp_handlers.update(_OCSP_SINGLERESP_EXTENSION_HANDLERS_SCT) self._certificate_extension_parser = _X509ExtensionParser( self, ext_count=self._lib.X509_get_ext_count, get_ext=self._lib.X509_get_ext, handlers=ext_handlers, ) self._csr_extension_parser = _X509ExtensionParser( self, ext_count=self._lib.sk_X509_EXTENSION_num, get_ext=self._lib.sk_X509_EXTENSION_value, handlers=ext_handlers, ) self._revoked_cert_extension_parser = _X509ExtensionParser( self, ext_count=self._lib.X509_REVOKED_get_ext_count, get_ext=self._lib.X509_REVOKED_get_ext, handlers=_REVOKED_EXTENSION_HANDLERS, ) self._crl_extension_parser = _X509ExtensionParser( self, ext_count=self._lib.X509_CRL_get_ext_count, get_ext=self._lib.X509_CRL_get_ext, handlers=_CRL_EXTENSION_HANDLERS, ) self._ocsp_req_ext_parser = _X509ExtensionParser( self, ext_count=self._lib.OCSP_REQUEST_get_ext_count, get_ext=self._lib.OCSP_REQUEST_get_ext, handlers=_OCSP_REQ_EXTENSION_HANDLERS, ) self._ocsp_basicresp_ext_parser = _X509ExtensionParser( self, ext_count=self._lib.OCSP_BASICRESP_get_ext_count, get_ext=self._lib.OCSP_BASICRESP_get_ext, handlers=_OCSP_BASICRESP_EXTENSION_HANDLERS, ) self._ocsp_singleresp_ext_parser = _X509ExtensionParser( self, ext_count=self._lib.OCSP_SINGLERESP_get_ext_count, get_ext=self._lib.OCSP_SINGLERESP_get_ext, handlers=singleresp_handlers, ) def _register_x509_encoders(self): self._extension_encode_handlers = _EXTENSION_ENCODE_HANDLERS.copy() self._crl_extension_encode_handlers = ( _CRL_EXTENSION_ENCODE_HANDLERS.copy() ) self._crl_entry_extension_encode_handlers = ( _CRL_ENTRY_EXTENSION_ENCODE_HANDLERS.copy() ) self._ocsp_request_extension_encode_handlers = ( _OCSP_REQUEST_EXTENSION_ENCODE_HANDLERS.copy() ) self._ocsp_basicresp_extension_encode_handlers = ( _OCSP_BASICRESP_EXTENSION_ENCODE_HANDLERS.copy() ) def create_symmetric_encryption_ctx(self, cipher, mode): return _CipherContext(self, cipher, mode, _CipherContext._ENCRYPT) def create_symmetric_decryption_ctx(self, cipher, mode): return _CipherContext(self, cipher, mode, _CipherContext._DECRYPT) def pbkdf2_hmac_supported(self, algorithm): return self.hmac_supported(algorithm) def derive_pbkdf2_hmac( self, algorithm, length, salt, iterations, key_material ): buf = self._ffi.new("unsigned char[]", length) evp_md = self._evp_md_non_null_from_algorithm(algorithm) key_material_ptr = self._ffi.from_buffer(key_material) res = self._lib.PKCS5_PBKDF2_HMAC( key_material_ptr, len(key_material), salt, len(salt), iterations, evp_md, length, buf, ) self.openssl_assert(res == 1) return self._ffi.buffer(buf)[:] def _consume_errors(self): return binding._consume_errors(self._lib) def _consume_errors_with_text(self): return binding._consume_errors_with_text(self._lib) def _bn_to_int(self, bn): assert bn != self._ffi.NULL if not six.PY2: # Python 3 has constant time from_bytes, so use that. bn_num_bytes = self._lib.BN_num_bytes(bn) 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 self.openssl_assert(bin_len >= 0) val = int.from_bytes(self._ffi.buffer(bin_ptr)[:bin_len], "big") if self._lib.BN_is_negative(bn): val = -val return val else: # Under Python 2 the best we can do is hex() hex_cdata = self._lib.BN_bn2hex(bn) self.openssl_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 not six.PY2: # 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) self.openssl_assert(bn_ptr != self._ffi.NULL) return bn_ptr else: # Under Python 2 the best we can do is hex(), [2:] removes the 0x # prefix. hex_num = hex(num).rstrip("L")[2:].encode("ascii") bn_ptr = self._ffi.new("BIGNUM **") bn_ptr[0] = bn res = self._lib.BN_hex2bn(bn_ptr, hex_num) self.openssl_assert(res != 0) self.openssl_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() self.openssl_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 ) self.openssl_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() self.openssl_assert(rsa_cdata != self._ffi.NULL) rsa_cdata = self._ffi.gc(rsa_cdata, self._lib.RSA_free) p = self._int_to_bn(numbers.p) q = self._int_to_bn(numbers.q) d = self._int_to_bn(numbers.d) dmp1 = self._int_to_bn(numbers.dmp1) dmq1 = self._int_to_bn(numbers.dmq1) iqmp = self._int_to_bn(numbers.iqmp) e = self._int_to_bn(numbers.public_numbers.e) n = self._int_to_bn(numbers.public_numbers.n) res = self._lib.RSA_set0_factors(rsa_cdata, p, q) self.openssl_assert(res == 1) res = self._lib.RSA_set0_key(rsa_cdata, n, e, d) self.openssl_assert(res == 1) res = self._lib.RSA_set0_crt_params(rsa_cdata, dmp1, dmq1, iqmp) self.openssl_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() self.openssl_assert(rsa_cdata != self._ffi.NULL) rsa_cdata = self._ffi.gc(rsa_cdata, self._lib.RSA_free) e = self._int_to_bn(numbers.e) n = self._int_to_bn(numbers.n) res = self._lib.RSA_set0_key(rsa_cdata, n, e, self._ffi.NULL) self.openssl_assert(res == 1) evp_pkey = self._rsa_cdata_to_evp_pkey(rsa_cdata) return _RSAPublicKey(self, rsa_cdata, evp_pkey) def _create_evp_pkey_gc(self): evp_pkey = self._lib.EVP_PKEY_new() self.openssl_assert(evp_pkey != self._ffi.NULL) evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free) return evp_pkey def _rsa_cdata_to_evp_pkey(self, rsa_cdata): evp_pkey = self._create_evp_pkey_gc() res = self._lib.EVP_PKEY_set1_RSA(evp_pkey, rsa_cdata) self.openssl_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_ptr = self._ffi.from_buffer(data) bio = self._lib.BIO_new_mem_buf(data_ptr, len(data)) self.openssl_assert(bio != self._ffi.NULL) return _MemoryBIO(self._ffi.gc(bio, self._lib.BIO_free), data_ptr) def _create_mem_bio_gc(self): """ Creates an empty memory BIO. """ bio_method = self._lib.BIO_s_mem() self.openssl_assert(bio_method != self._ffi.NULL) bio = self._lib.BIO_new(bio_method) self.openssl_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) self.openssl_assert(buf_len > 0) self.openssl_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 = self._lib.EVP_PKEY_id(evp_pkey) if key_type == self._lib.EVP_PKEY_RSA: rsa_cdata = self._lib.EVP_PKEY_get1_RSA(evp_pkey) self.openssl_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) self.openssl_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 key_type == self._lib.EVP_PKEY_EC: ec_cdata = self._lib.EVP_PKEY_get1_EC_KEY(evp_pkey) self.openssl_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) elif key_type in self._dh_types: dh_cdata = self._lib.EVP_PKEY_get1_DH(evp_pkey) self.openssl_assert(dh_cdata != self._ffi.NULL) dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free) return _DHPrivateKey(self, dh_cdata, evp_pkey) elif key_type == getattr(self._lib, "EVP_PKEY_ED25519", None): # EVP_PKEY_ED25519 is not present in OpenSSL < 1.1.1 return _Ed25519PrivateKey(self, evp_pkey) elif key_type == getattr(self._lib, "EVP_PKEY_X448", None): # EVP_PKEY_X448 is not present in OpenSSL < 1.1.1 return _X448PrivateKey(self, evp_pkey) elif key_type == getattr(self._lib, "EVP_PKEY_X25519", None): # EVP_PKEY_X25519 is not present in OpenSSL < 1.1.0 return _X25519PrivateKey(self, evp_pkey) elif key_type == getattr(self._lib, "EVP_PKEY_ED448", None): # EVP_PKEY_ED448 is not present in OpenSSL < 1.1.1 return _Ed448PrivateKey(self, 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 = self._lib.EVP_PKEY_id(evp_pkey) if key_type == self._lib.EVP_PKEY_RSA: rsa_cdata = self._lib.EVP_PKEY_get1_RSA(evp_pkey) self.openssl_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) self.openssl_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 key_type == self._lib.EVP_PKEY_EC: ec_cdata = self._lib.EVP_PKEY_get1_EC_KEY(evp_pkey) self.openssl_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) elif key_type in self._dh_types: dh_cdata = self._lib.EVP_PKEY_get1_DH(evp_pkey) self.openssl_assert(dh_cdata != self._ffi.NULL) dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free) return _DHPublicKey(self, dh_cdata, evp_pkey) elif key_type == getattr(self._lib, "EVP_PKEY_ED25519", None): # EVP_PKEY_ED25519 is not present in OpenSSL < 1.1.1 return _Ed25519PublicKey(self, evp_pkey) elif key_type == getattr(self._lib, "EVP_PKEY_X448", None): # EVP_PKEY_X448 is not present in OpenSSL < 1.1.1 return _X448PublicKey(self, evp_pkey) elif key_type == getattr(self._lib, "EVP_PKEY_X25519", None): # EVP_PKEY_X25519 is not present in OpenSSL < 1.1.0 return _X25519PublicKey(self, evp_pkey) elif key_type == getattr(self._lib, "EVP_PKEY_ED448", None): # EVP_PKEY_X25519 is not present in OpenSSL < 1.1.1 return _Ed448PublicKey(self, evp_pkey) else: raise UnsupportedAlgorithm("Unsupported key type.") def _oaep_hash_supported(self, algorithm): if self._lib.Cryptography_HAS_RSA_OAEP_MD: return isinstance( algorithm, ( hashes.SHA1, hashes.SHA224, hashes.SHA256, hashes.SHA384, hashes.SHA512, ), ) 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.hash_supported(padding._mgf._algorithm) elif isinstance(padding, OAEP) and isinstance(padding._mgf, MGF1): return ( self._oaep_hash_supported(padding._mgf._algorithm) and self._oaep_hash_supported(padding._algorithm) and ( (padding._label is None or len(padding._label) == 0) or self._lib.Cryptography_HAS_RSA_OAEP_LABEL == 1 ) ) else: return False def generate_dsa_parameters(self, key_size): if key_size not in (1024, 2048, 3072, 4096): raise ValueError( "Key size must be 1024, 2048, 3072, or 4096 bits." ) ctx = self._lib.DSA_new() self.openssl_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, ) self.openssl_assert(res == 1) return _DSAParameters(self, ctx) def generate_dsa_private_key(self, parameters): ctx = self._lib.DSAparams_dup(parameters._dsa_cdata) self.openssl_assert(ctx != self._ffi.NULL) ctx = self._ffi.gc(ctx, self._lib.DSA_free) 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 _dsa_cdata_set_values(self, dsa_cdata, p, q, g, pub_key, priv_key): res = self._lib.DSA_set0_pqg(dsa_cdata, p, q, g) self.openssl_assert(res == 1) res = self._lib.DSA_set0_key(dsa_cdata, pub_key, priv_key) self.openssl_assert(res == 1) 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() self.openssl_assert(dsa_cdata != self._ffi.NULL) dsa_cdata = self._ffi.gc(dsa_cdata, self._lib.DSA_free) p = self._int_to_bn(parameter_numbers.p) q = self._int_to_bn(parameter_numbers.q) g = self._int_to_bn(parameter_numbers.g) pub_key = self._int_to_bn(numbers.public_numbers.y) priv_key = self._int_to_bn(numbers.x) self._dsa_cdata_set_values(dsa_cdata, p, q, g, pub_key, priv_key) 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() self.openssl_assert(dsa_cdata != self._ffi.NULL) dsa_cdata = self._ffi.gc(dsa_cdata, self._lib.DSA_free) p = self._int_to_bn(numbers.parameter_numbers.p) q = self._int_to_bn(numbers.parameter_numbers.q) g = self._int_to_bn(numbers.parameter_numbers.g) pub_key = self._int_to_bn(numbers.y) priv_key = self._ffi.NULL self._dsa_cdata_set_values(dsa_cdata, p, q, g, pub_key, priv_key) 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() self.openssl_assert(dsa_cdata != self._ffi.NULL) dsa_cdata = self._ffi.gc(dsa_cdata, self._lib.DSA_free) p = self._int_to_bn(numbers.p) q = self._int_to_bn(numbers.q) g = self._int_to_bn(numbers.g) res = self._lib.DSA_set0_pqg(dsa_cdata, p, q, g) self.openssl_assert(res == 1) return _DSAParameters(self, dsa_cdata) def _dsa_cdata_to_evp_pkey(self, dsa_cdata): evp_pkey = self._create_evp_pkey_gc() res = self._lib.EVP_PKEY_set1_DSA(evp_pkey, dsa_cdata) self.openssl_assert(res == 1) return evp_pkey def dsa_hash_supported(self, algorithm): return self.hash_supported(algorithm) def dsa_parameters_supported(self, p, q, g): return True def cmac_algorithm_supported(self, algorithm): return self.cipher_supported( algorithm, CBC(b"\x00" * algorithm.block_size) ) def create_cmac_ctx(self, algorithm): return _CMACContext(self, algorithm) def _x509_check_signature_params(self, private_key, algorithm): if isinstance( private_key, (ed25519.Ed25519PrivateKey, ed448.Ed448PrivateKey) ): if algorithm is not None: raise ValueError( "algorithm must be None when signing via ed25519 or ed448" ) elif not isinstance( private_key, (rsa.RSAPrivateKey, dsa.DSAPrivateKey, ec.EllipticCurvePrivateKey), ): raise TypeError( "Key must be an rsa, dsa, ec, ed25519, or ed448 private key." ) elif not isinstance(algorithm, hashes.HashAlgorithm): raise TypeError("Algorithm must be a registered hash algorithm.") elif isinstance(algorithm, hashes.MD5) and not isinstance( private_key, rsa.RSAPrivateKey ): raise ValueError( "MD5 hash algorithm is only supported with RSA keys" ) def create_x509_csr(self, builder, private_key, algorithm): if not isinstance(builder, x509.CertificateSigningRequestBuilder): raise TypeError("Builder type mismatch.") self._x509_check_signature_params(private_key, algorithm) # Resolve the signature algorithm. evp_md = self._evp_md_x509_null_if_eddsa(private_key, algorithm) # Create an empty request. x509_req = self._lib.X509_REQ_new() self.openssl_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) self.openssl_assert(res == 1) # Set subject name. res = self._lib.X509_REQ_set_subject_name( x509_req, _encode_name_gc(self, builder._subject_name) ) self.openssl_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) self.openssl_assert(res == 1) # Add extensions. sk_extension = self._lib.sk_X509_EXTENSION_new_null() self.openssl_assert(sk_extension != self._ffi.NULL) sk_extension = self._ffi.gc( sk_extension, lambda x: self._lib.sk_X509_EXTENSION_pop_free( x, self._ffi.addressof( self._lib._original_lib, "X509_EXTENSION_free" ), ), ) # Don't GC individual extensions because the memory is owned by # sk_extensions and will be freed along with it. self._create_x509_extensions( extensions=builder._extensions, handlers=self._extension_encode_handlers, x509_obj=sk_extension, add_func=self._lib.sk_X509_EXTENSION_insert, gc=False, ) res = self._lib.X509_REQ_add_extensions(x509_req, sk_extension) self.openssl_assert(res == 1) # Add attributes (all bytes encoded as ASN1 UTF8_STRING) for attr_oid, attr_val in builder._attributes: obj = _txt2obj_gc(self, attr_oid.dotted_string) res = self._lib.X509_REQ_add1_attr_by_OBJ( x509_req, obj, x509.name._ASN1Type.UTF8String.value, attr_val, len(attr_val), ) self.openssl_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) if res == 0: errors = self._consume_errors_with_text() raise ValueError("Signing failed", errors) return _CertificateSigningRequest(self, x509_req) def create_x509_certificate(self, builder, private_key, algorithm): if not isinstance(builder, x509.CertificateBuilder): raise TypeError("Builder type mismatch.") self._x509_check_signature_params(private_key, algorithm) # Resolve the signature algorithm. evp_md = self._evp_md_x509_null_if_eddsa(private_key, algorithm) # Create an empty certificate. x509_cert = self._lib.X509_new() x509_cert = self._ffi.gc(x509_cert, self._lib.X509_free) # Set the x509 version. res = self._lib.X509_set_version(x509_cert, builder._version.value) self.openssl_assert(res == 1) # Set the subject's name. res = self._lib.X509_set_subject_name( x509_cert, _encode_name_gc(self, builder._subject_name) ) self.openssl_assert(res == 1) # Set the subject's public key. res = self._lib.X509_set_pubkey( x509_cert, builder._public_key._evp_pkey ) self.openssl_assert(res == 1) # Set the certificate serial number. serial_number = _encode_asn1_int_gc(self, builder._serial_number) res = self._lib.X509_set_serialNumber(x509_cert, serial_number) self.openssl_assert(res == 1) # Set the "not before" time. self._set_asn1_time( self._lib.X509_getm_notBefore(x509_cert), builder._not_valid_before ) # Set the "not after" time. self._set_asn1_time( self._lib.X509_getm_notAfter(x509_cert), builder._not_valid_after ) # Add extensions. self._create_x509_extensions( extensions=builder._extensions, handlers=self._extension_encode_handlers, x509_obj=x509_cert, add_func=self._lib.X509_add_ext, gc=True, ) # Set the issuer name. res = self._lib.X509_set_issuer_name( x509_cert, _encode_name_gc(self, builder._issuer_name) ) self.openssl_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) if res == 0: errors = self._consume_errors_with_text() raise ValueError("Signing failed", errors) return _Certificate(self, x509_cert) def _evp_md_x509_null_if_eddsa(self, private_key, algorithm): if isinstance( private_key, (ed25519.Ed25519PrivateKey, ed448.Ed448PrivateKey) ): # OpenSSL requires us to pass NULL for EVP_MD for ed25519/ed448 return self._ffi.NULL else: return self._evp_md_non_null_from_algorithm(algorithm) def _set_asn1_time(self, asn1_time, time): if time.year >= 2050: asn1_str = time.strftime("%Y%m%d%H%M%SZ").encode("ascii") else: asn1_str = time.strftime("%y%m%d%H%M%SZ").encode("ascii") res = self._lib.ASN1_TIME_set_string(asn1_time, asn1_str) self.openssl_assert(res == 1) def _create_asn1_time(self, time): asn1_time = self._lib.ASN1_TIME_new() self.openssl_assert(asn1_time != self._ffi.NULL) asn1_time = self._ffi.gc(asn1_time, self._lib.ASN1_TIME_free) self._set_asn1_time(asn1_time, time) return asn1_time def create_x509_crl(self, builder, private_key, algorithm): if not isinstance(builder, x509.CertificateRevocationListBuilder): raise TypeError("Builder type mismatch.") self._x509_check_signature_params(private_key, algorithm) evp_md = self._evp_md_x509_null_if_eddsa(private_key, algorithm) # Create an empty CRL. x509_crl = self._lib.X509_CRL_new() x509_crl = self._ffi.gc(x509_crl, self._lib.X509_CRL_free) # Set the x509 CRL version. We only support v2 (integer value 1). res = self._lib.X509_CRL_set_version(x509_crl, 1) self.openssl_assert(res == 1) # Set the issuer name. res = self._lib.X509_CRL_set_issuer_name( x509_crl, _encode_name_gc(self, builder._issuer_name) ) self.openssl_assert(res == 1) # Set the last update time. last_update = self._create_asn1_time(builder._last_update) res = self._lib.X509_CRL_set_lastUpdate(x509_crl, last_update) self.openssl_assert(res == 1) # Set the next update time. next_update = self._create_asn1_time(builder._next_update) res = self._lib.X509_CRL_set_nextUpdate(x509_crl, next_update) self.openssl_assert(res == 1) # Add extensions. self._create_x509_extensions( extensions=builder._extensions, handlers=self._crl_extension_encode_handlers, x509_obj=x509_crl, add_func=self._lib.X509_CRL_add_ext, gc=True, ) # add revoked certificates for revoked_cert in builder._revoked_certificates: # Duplicating because the X509_CRL takes ownership and will free # this memory when X509_CRL_free is called. revoked = self._lib.X509_REVOKED_dup(revoked_cert._x509_revoked) self.openssl_assert(revoked != self._ffi.NULL) res = self._lib.X509_CRL_add0_revoked(x509_crl, revoked) self.openssl_assert(res == 1) res = self._lib.X509_CRL_sign(x509_crl, private_key._evp_pkey, evp_md) if res == 0: errors = self._consume_errors_with_text() raise ValueError("Signing failed", errors) return _CertificateRevocationList(self, x509_crl) def _create_x509_extensions( self, extensions, handlers, x509_obj, add_func, gc ): for i, extension in enumerate(extensions): x509_extension = self._create_x509_extension(handlers, extension) self.openssl_assert(x509_extension != self._ffi.NULL) if gc: x509_extension = self._ffi.gc( x509_extension, self._lib.X509_EXTENSION_free ) res = add_func(x509_obj, x509_extension, i) self.openssl_assert(res >= 1) def _create_raw_x509_extension(self, extension, value): obj = _txt2obj_gc(self, extension.oid.dotted_string) return self._lib.X509_EXTENSION_create_by_OBJ( self._ffi.NULL, obj, 1 if extension.critical else 0, value ) def _create_x509_extension(self, handlers, extension): if isinstance(extension.value, x509.UnrecognizedExtension): value = _encode_asn1_str_gc(self, extension.value.value) return self._create_raw_x509_extension(extension, value) elif isinstance(extension.value, x509.TLSFeature): asn1 = encode_der( SEQUENCE, *[ encode_der(INTEGER, encode_der_integer(x.value)) for x in extension.value ] ) value = _encode_asn1_str_gc(self, asn1) return self._create_raw_x509_extension(extension, value) elif isinstance(extension.value, x509.PrecertPoison): value = _encode_asn1_str_gc(self, encode_der(NULL)) return self._create_raw_x509_extension(extension, value) else: try: encode = handlers[extension.oid] except KeyError: raise NotImplementedError( "Extension not supported: {}".format(extension.oid) ) ext_struct = encode(self, extension.value) nid = self._lib.OBJ_txt2nid( extension.oid.dotted_string.encode("ascii") ) self.openssl_assert(nid != self._lib.NID_undef) return self._lib.X509V3_EXT_i2d( nid, 1 if extension.critical else 0, ext_struct ) def create_x509_revoked_certificate(self, builder): if not isinstance(builder, x509.RevokedCertificateBuilder): raise TypeError("Builder type mismatch.") x509_revoked = self._lib.X509_REVOKED_new() self.openssl_assert(x509_revoked != self._ffi.NULL) x509_revoked = self._ffi.gc(x509_revoked, self._lib.X509_REVOKED_free) serial_number = _encode_asn1_int_gc(self, builder._serial_number) res = self._lib.X509_REVOKED_set_serialNumber( x509_revoked, serial_number ) self.openssl_assert(res == 1) rev_date = self._create_asn1_time(builder._revocation_date) res = self._lib.X509_REVOKED_set_revocationDate(x509_revoked, rev_date) self.openssl_assert(res == 1) # add CRL entry extensions self._create_x509_extensions( extensions=builder._extensions, handlers=self._crl_entry_extension_encode_handlers, x509_obj=x509_revoked, add_func=self._lib.X509_REVOKED_add_ext, gc=True, ) return _RevokedCertificate(self, None, x509_revoked) 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) self.openssl_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_pem_parameters(self, data): mem_bio = self._bytes_to_bio(data) # only DH is supported currently dh_cdata = self._lib.PEM_read_bio_DHparams( mem_bio.bio, self._ffi.NULL, self._ffi.NULL, self._ffi.NULL ) if dh_cdata != self._ffi.NULL: dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free) return _DHParameters(self, dh_cdata) else: self._handle_key_loading_error() def load_der_private_key(self, data, password): # OpenSSL has a function called d2i_AutoPrivateKey that in theory # handles this automatically, however it doesn't handle encrypted # private keys. Instead we try to load the key two 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 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 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) self.openssl_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_der_parameters(self, data): mem_bio = self._bytes_to_bio(data) dh_cdata = self._lib.d2i_DHparams_bio(mem_bio.bio, self._ffi.NULL) if dh_cdata != self._ffi.NULL: dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free) return _DHParameters(self, dh_cdata) elif self._lib.Cryptography_HAS_EVP_PKEY_DHX: # We check to see if the is dhx. self._consume_errors() res = self._lib.BIO_reset(mem_bio.bio) self.openssl_assert(res == 1) dh_cdata = self._lib.Cryptography_d2i_DHxparams_bio( mem_bio.bio, self._ffi.NULL ) if dh_cdata != self._ffi.NULL: dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free) return _DHParameters(self, dh_cdata) 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. See https://cryptography.io/en/la" "test/faq/#why-can-t-i-import-my-pem-file for more details." ) 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_crl(self, data): mem_bio = self._bytes_to_bio(data) x509_crl = self._lib.PEM_read_bio_X509_CRL( mem_bio.bio, self._ffi.NULL, self._ffi.NULL, self._ffi.NULL ) if x509_crl == self._ffi.NULL: self._consume_errors() raise ValueError( "Unable to load CRL. See https://cryptography.io/en/la" "test/faq/#why-can-t-i-import-my-pem-file for more details." ) x509_crl = self._ffi.gc(x509_crl, self._lib.X509_CRL_free) return _CertificateRevocationList(self, x509_crl) def load_der_x509_crl(self, data): mem_bio = self._bytes_to_bio(data) x509_crl = self._lib.d2i_X509_CRL_bio(mem_bio.bio, self._ffi.NULL) if x509_crl == self._ffi.NULL: self._consume_errors() raise ValueError("Unable to load CRL") x509_crl = self._ffi.gc(x509_crl, self._lib.X509_CRL_free) return _CertificateRevocationList(self, x509_crl) 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. See https://cryptography.io/en/la" "test/faq/#why-can-t-i-import-my-pem-file for more details." ) 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) userdata = self._ffi.new("CRYPTOGRAPHY_PASSWORD_DATA *") if password is not None: utils._check_byteslike("password", password) password_ptr = self._ffi.from_buffer(password) userdata.password = password_ptr userdata.length = len(password) evp_pkey = openssl_read_func( mem_bio.bio, self._ffi.NULL, self._ffi.addressof( self._lib._original_lib, "Cryptography_pem_password_cb" ), userdata, ) if evp_pkey == self._ffi.NULL: if userdata.error != 0: errors = self._consume_errors() self.openssl_assert(errors) if userdata.error == -1: raise TypeError( "Password was not given but private key is encrypted" ) else: assert userdata.error == -2 raise ValueError( "Passwords longer than {} bytes are not supported " "by this backend.".format(userdata.maxsize - 1) ) else: self._handle_key_loading_error() evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free) if password is not None and userdata.called == 0: raise TypeError( "Password was given but private key is not encrypted." ) assert ( password is not None and userdata.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 deserialize key data.") elif errors[0]._lib_reason_match( self._lib.ERR_LIB_EVP, self._lib.EVP_R_BAD_DECRYPT ) or errors[0]._lib_reason_match( self._lib.ERR_LIB_PKCS12, self._lib.PKCS12_R_PKCS12_CIPHERFINAL_ERROR, ): raise ValueError("Bad decrypt. Incorrect password?") elif errors[0]._lib_reason_match( self._lib.ERR_LIB_EVP, self._lib.EVP_R_UNKNOWN_PBE_ALGORITHM ) or errors[0]._lib_reason_match( self._lib.ERR_LIB_PEM, self._lib.PEM_R_UNSUPPORTED_ENCRYPTION ): raise UnsupportedAlgorithm( "PEM data is encrypted with an unsupported cipher", _Reasons.UNSUPPORTED_CIPHER, ) elif any( error._lib_reason_match( self._lib.ERR_LIB_EVP, self._lib.EVP_R_UNSUPPORTED_PRIVATE_KEY_ALGORITHM, ) for error in errors ): raise ValueError("Unsupported public key algorithm.") else: assert errors[0].lib in ( self._lib.ERR_LIB_EVP, self._lib.ERR_LIB_PEM, self._lib.ERR_LIB_ASN1, ) raise ValueError("Could not deserialize key data.") def elliptic_curve_supported(self, curve): try: curve_nid = self._elliptic_curve_to_nid(curve) except UnsupportedAlgorithm: curve_nid = self._lib.NID_undef group = self._lib.EC_GROUP_new_by_curve_name(curve_nid) if group == self._ffi.NULL: self._consume_errors() return False else: self.openssl_assert(curve_nid != self._lib.NID_undef) self._lib.EC_GROUP_free(group) return True def elliptic_curve_signature_algorithm_supported( self, signature_algorithm, curve ): # We only support ECDSA right now. if not isinstance(signature_algorithm, ec.ECDSA): 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): ec_cdata = self._ec_key_new_by_curve(curve) res = self._lib.EC_KEY_generate_key(ec_cdata) self.openssl_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 {}.".format(curve.name), _Reasons.UNSUPPORTED_ELLIPTIC_CURVE, ) def load_elliptic_curve_private_numbers(self, numbers): public = numbers.public_numbers ec_cdata = self._ec_key_new_by_curve(public.curve) private_value = self._ffi.gc( self._int_to_bn(numbers.private_value), self._lib.BN_clear_free ) res = self._lib.EC_KEY_set_private_key(ec_cdata, private_value) self.openssl_assert(res == 1) ec_cdata = self._ec_key_set_public_key_affine_coordinates( ec_cdata, public.x, public.y ) 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): ec_cdata = self._ec_key_new_by_curve(numbers.curve) 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 load_elliptic_curve_public_bytes(self, curve, point_bytes): ec_cdata = self._ec_key_new_by_curve(curve) group = self._lib.EC_KEY_get0_group(ec_cdata) self.openssl_assert(group != self._ffi.NULL) point = self._lib.EC_POINT_new(group) self.openssl_assert(point != self._ffi.NULL) point = self._ffi.gc(point, self._lib.EC_POINT_free) with self._tmp_bn_ctx() as bn_ctx: res = self._lib.EC_POINT_oct2point( group, point, point_bytes, len(point_bytes), bn_ctx ) if res != 1: self._consume_errors() raise ValueError("Invalid public bytes for the given curve") res = self._lib.EC_KEY_set_public_key(ec_cdata, point) self.openssl_assert(res == 1) evp_pkey = self._ec_cdata_to_evp_pkey(ec_cdata) return _EllipticCurvePublicKey(self, ec_cdata, evp_pkey) def derive_elliptic_curve_private_key(self, private_value, curve): ec_cdata = self._ec_key_new_by_curve(curve) get_func, group = self._ec_key_determine_group_get_func(ec_cdata) point = self._lib.EC_POINT_new(group) self.openssl_assert(point != self._ffi.NULL) point = self._ffi.gc(point, self._lib.EC_POINT_free) value = self._int_to_bn(private_value) value = self._ffi.gc(value, self._lib.BN_clear_free) with self._tmp_bn_ctx() as bn_ctx: res = self._lib.EC_POINT_mul( group, point, value, self._ffi.NULL, self._ffi.NULL, bn_ctx ) self.openssl_assert(res == 1) bn_x = self._lib.BN_CTX_get(bn_ctx) bn_y = self._lib.BN_CTX_get(bn_ctx) res = get_func(group, point, bn_x, bn_y, bn_ctx) self.openssl_assert(res == 1) res = self._lib.EC_KEY_set_public_key(ec_cdata, point) self.openssl_assert(res == 1) private = self._int_to_bn(private_value) private = self._ffi.gc(private, self._lib.BN_clear_free) res = self._lib.EC_KEY_set_private_key(ec_cdata, private) self.openssl_assert(res == 1) evp_pkey = self._ec_cdata_to_evp_pkey(ec_cdata) return _EllipticCurvePrivateKey(self, ec_cdata, evp_pkey) def _ec_key_new_by_curve(self, curve): curve_nid = self._elliptic_curve_to_nid(curve) return self._ec_key_new_by_curve_nid(curve_nid) def _ec_key_new_by_curve_nid(self, curve_nid): ec_cdata = self._lib.EC_KEY_new_by_curve_name(curve_nid) self.openssl_assert(ec_cdata != self._ffi.NULL) # Setting the ASN.1 flag to OPENSSL_EC_NAMED_CURVE is # only necessary on OpenSSL 1.0.2t/u. Once we drop support for 1.0.2 # we can remove this as it's done automatically when getting an EC_KEY # from new_by_curve_name # CRYPTOGRAPHY_OPENSSL_102U_OR_GREATER self._lib.EC_KEY_set_asn1_flag( ec_cdata, backend._lib.OPENSSL_EC_NAMED_CURVE ) return self._ffi.gc(ec_cdata, self._lib.EC_KEY_free) def load_der_ocsp_request(self, data): mem_bio = self._bytes_to_bio(data) request = self._lib.d2i_OCSP_REQUEST_bio(mem_bio.bio, self._ffi.NULL) if request == self._ffi.NULL: self._consume_errors() raise ValueError("Unable to load OCSP request") request = self._ffi.gc(request, self._lib.OCSP_REQUEST_free) return _OCSPRequest(self, request) def load_der_ocsp_response(self, data): mem_bio = self._bytes_to_bio(data) response = self._lib.d2i_OCSP_RESPONSE_bio(mem_bio.bio, self._ffi.NULL) if response == self._ffi.NULL: self._consume_errors() raise ValueError("Unable to load OCSP response") response = self._ffi.gc(response, self._lib.OCSP_RESPONSE_free) return _OCSPResponse(self, response) def create_ocsp_request(self, builder): ocsp_req = self._lib.OCSP_REQUEST_new() self.openssl_assert(ocsp_req != self._ffi.NULL) ocsp_req = self._ffi.gc(ocsp_req, self._lib.OCSP_REQUEST_free) cert, issuer, algorithm = builder._request evp_md = self._evp_md_non_null_from_algorithm(algorithm) certid = self._lib.OCSP_cert_to_id(evp_md, cert._x509, issuer._x509) self.openssl_assert(certid != self._ffi.NULL) onereq = self._lib.OCSP_request_add0_id(ocsp_req, certid) self.openssl_assert(onereq != self._ffi.NULL) self._create_x509_extensions( extensions=builder._extensions, handlers=self._ocsp_request_extension_encode_handlers, x509_obj=ocsp_req, add_func=self._lib.OCSP_REQUEST_add_ext, gc=True, ) return _OCSPRequest(self, ocsp_req) def _create_ocsp_basic_response(self, builder, private_key, algorithm): self._x509_check_signature_params(private_key, algorithm) basic = self._lib.OCSP_BASICRESP_new() self.openssl_assert(basic != self._ffi.NULL) basic = self._ffi.gc(basic, self._lib.OCSP_BASICRESP_free) evp_md = self._evp_md_non_null_from_algorithm( builder._response._algorithm ) certid = self._lib.OCSP_cert_to_id( evp_md, builder._response._cert._x509, builder._response._issuer._x509, ) self.openssl_assert(certid != self._ffi.NULL) certid = self._ffi.gc(certid, self._lib.OCSP_CERTID_free) if builder._response._revocation_reason is None: reason = -1 else: reason = _CRL_ENTRY_REASON_ENUM_TO_CODE[ builder._response._revocation_reason ] if builder._response._revocation_time is None: rev_time = self._ffi.NULL else: rev_time = self._create_asn1_time( builder._response._revocation_time ) next_update = self._ffi.NULL if builder._response._next_update is not None: next_update = self._create_asn1_time( builder._response._next_update ) this_update = self._create_asn1_time(builder._response._this_update) res = self._lib.OCSP_basic_add1_status( basic, certid, builder._response._cert_status.value, reason, rev_time, this_update, next_update, ) self.openssl_assert(res != self._ffi.NULL) # okay, now sign the basic structure evp_md = self._evp_md_x509_null_if_eddsa(private_key, algorithm) responder_cert, responder_encoding = builder._responder_id flags = self._lib.OCSP_NOCERTS if responder_encoding is ocsp.OCSPResponderEncoding.HASH: flags |= self._lib.OCSP_RESPID_KEY if builder._certs is not None: for cert in builder._certs: res = self._lib.OCSP_basic_add1_cert(basic, cert._x509) self.openssl_assert(res == 1) self._create_x509_extensions( extensions=builder._extensions, handlers=self._ocsp_basicresp_extension_encode_handlers, x509_obj=basic, add_func=self._lib.OCSP_BASICRESP_add_ext, gc=True, ) res = self._lib.OCSP_basic_sign( basic, responder_cert._x509, private_key._evp_pkey, evp_md, self._ffi.NULL, flags, ) if res != 1: errors = self._consume_errors_with_text() raise ValueError( "Error while signing. responder_cert must be signed " "by private_key", errors, ) return basic def create_ocsp_response( self, response_status, builder, private_key, algorithm ): if response_status is ocsp.OCSPResponseStatus.SUCCESSFUL: basic = self._create_ocsp_basic_response( builder, private_key, algorithm ) else: basic = self._ffi.NULL ocsp_resp = self._lib.OCSP_response_create( response_status.value, basic ) self.openssl_assert(ocsp_resp != self._ffi.NULL) ocsp_resp = self._ffi.gc(ocsp_resp, self._lib.OCSP_RESPONSE_free) return _OCSPResponse(self, ocsp_resp) def elliptic_curve_exchange_algorithm_supported(self, algorithm, curve): return self.elliptic_curve_supported(curve) and isinstance( algorithm, ec.ECDH ) def _ec_cdata_to_evp_pkey(self, ec_cdata): evp_pkey = self._create_evp_pkey_gc() res = self._lib.EVP_PKEY_set1_EC_KEY(evp_pkey, ec_cdata) self.openssl_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( "{} 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() self.openssl_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_func(self, ctx): """ Given an EC_KEY determine the group and what function is required to get point coordinates. """ self.openssl_assert(ctx != self._ffi.NULL) nid_two_field = self._lib.OBJ_sn2nid(b"characteristic-two-field") self.openssl_assert(nid_two_field != self._lib.NID_undef) group = self._lib.EC_KEY_get0_group(ctx) self.openssl_assert(group != self._ffi.NULL) method = self._lib.EC_GROUP_method_of(group) self.openssl_assert(method != self._ffi.NULL) nid = self._lib.EC_METHOD_get_field_type(method) self.openssl_assert(nid != self._lib.NID_undef) if nid == nid_two_field and self._lib.Cryptography_HAS_EC2M: get_func = self._lib.EC_POINT_get_affine_coordinates_GF2m else: get_func = self._lib.EC_POINT_get_affine_coordinates_GFp assert get_func return get_func, group def _ec_key_set_public_key_affine_coordinates(self, ctx, x, y): """ 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." ) x = self._ffi.gc(self._int_to_bn(x), self._lib.BN_free) y = self._ffi.gc(self._int_to_bn(y), self._lib.BN_free) res = self._lib.EC_KEY_set_public_key_affine_coordinates(ctx, x, y) if res != 1: self._consume_errors() raise ValueError("Invalid EC key.") return ctx def _private_key_bytes( self, encoding, format, encryption_algorithm, key, evp_pkey, cdata ): # validate argument types if not isinstance(encoding, serialization.Encoding): raise TypeError("encoding must be an item from the Encoding enum") 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" ) # validate password if isinstance(encryption_algorithm, serialization.NoEncryption): password = b"" elif isinstance( encryption_algorithm, serialization.BestAvailableEncryption ): password = encryption_algorithm.password if len(password) > 1023: raise ValueError( "Passwords longer than 1023 bytes are not supported by " "this backend" ) else: raise ValueError("Unsupported encryption type") # PKCS8 + PEM/DER if format is serialization.PrivateFormat.PKCS8: if encoding is serialization.Encoding.PEM: write_bio = self._lib.PEM_write_bio_PKCS8PrivateKey elif encoding is serialization.Encoding.DER: write_bio = self._lib.i2d_PKCS8PrivateKey_bio else: raise ValueError("Unsupported encoding for PKCS8") return self._private_key_bytes_via_bio( write_bio, evp_pkey, password ) # TraditionalOpenSSL + PEM/DER if format is serialization.PrivateFormat.TraditionalOpenSSL: if self._fips_enabled and not isinstance( encryption_algorithm, serialization.NoEncryption ): raise ValueError( "Encrypted traditional OpenSSL format is not " "supported in FIPS mode." ) key_type = self._lib.EVP_PKEY_id(evp_pkey) if encoding is serialization.Encoding.PEM: if key_type == self._lib.EVP_PKEY_RSA: write_bio = self._lib.PEM_write_bio_RSAPrivateKey elif key_type == self._lib.EVP_PKEY_DSA: write_bio = self._lib.PEM_write_bio_DSAPrivateKey elif key_type == self._lib.EVP_PKEY_EC: write_bio = self._lib.PEM_write_bio_ECPrivateKey else: raise ValueError( "Unsupported key type for TraditionalOpenSSL" ) return self._private_key_bytes_via_bio( write_bio, cdata, password ) if encoding is serialization.Encoding.DER: if password: raise ValueError( "Encryption is not supported for DER encoded " "traditional OpenSSL keys" ) if key_type == self._lib.EVP_PKEY_RSA: write_bio = self._lib.i2d_RSAPrivateKey_bio elif 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 else: raise ValueError( "Unsupported key type for TraditionalOpenSSL" ) return self._bio_func_output(write_bio, cdata) raise ValueError("Unsupported encoding for TraditionalOpenSSL") # OpenSSH + PEM if format is serialization.PrivateFormat.OpenSSH: if encoding is serialization.Encoding.PEM: return ssh.serialize_ssh_private_key(key, password) raise ValueError( "OpenSSH private key format can only be used" " with PEM encoding" ) # Anything that key-specific code was supposed to handle earlier, # like Raw. raise ValueError("format is invalid with this key") def _private_key_bytes_via_bio(self, write_bio, evp_pkey, password): if not password: evp_cipher = self._ffi.NULL else: # This is a curated value that we will update over time. evp_cipher = self._lib.EVP_get_cipherbyname(b"aes-256-cbc") return self._bio_func_output( write_bio, evp_pkey, evp_cipher, password, len(password), self._ffi.NULL, self._ffi.NULL, ) def _bio_func_output(self, write_bio, *args): bio = self._create_mem_bio_gc() res = write_bio(bio, *args) self.openssl_assert(res == 1) return self._read_mem_bio(bio) def _public_key_bytes(self, encoding, format, key, evp_pkey, cdata): if not isinstance(encoding, serialization.Encoding): raise TypeError("encoding must be an item from the Encoding enum") if not isinstance(format, serialization.PublicFormat): raise TypeError( "format must be an item from the PublicFormat enum" ) # SubjectPublicKeyInfo + PEM/DER 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 else: raise ValueError( "SubjectPublicKeyInfo works only with PEM or DER encoding" ) return self._bio_func_output(write_bio, evp_pkey) # PKCS1 + PEM/DER if format is serialization.PublicFormat.PKCS1: # Only RSA is supported here. key_type = self._lib.EVP_PKEY_id(evp_pkey) if key_type != self._lib.EVP_PKEY_RSA: raise ValueError("PKCS1 format is supported only for RSA keys") 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 else: raise ValueError("PKCS1 works only with PEM or DER encoding") return self._bio_func_output(write_bio, cdata) # OpenSSH + OpenSSH if format is serialization.PublicFormat.OpenSSH: if encoding is serialization.Encoding.OpenSSH: return ssh.serialize_ssh_public_key(key) raise ValueError( "OpenSSH format must be used with OpenSSH encoding" ) # Anything that key-specific code was supposed to handle earlier, # like Raw, CompressedPoint, UncompressedPoint raise ValueError("format is invalid with this key") def _parameter_bytes(self, encoding, format, cdata): if encoding is serialization.Encoding.OpenSSH: raise TypeError("OpenSSH encoding is not supported") # Only DH is supported here currently. q = self._ffi.new("BIGNUM **") self._lib.DH_get0_pqg(cdata, self._ffi.NULL, q, self._ffi.NULL) if encoding is serialization.Encoding.PEM: if q[0] != self._ffi.NULL: write_bio = self._lib.PEM_write_bio_DHxparams else: write_bio = self._lib.PEM_write_bio_DHparams elif encoding is serialization.Encoding.DER: if q[0] != self._ffi.NULL: write_bio = self._lib.Cryptography_i2d_DHxparams_bio else: write_bio = self._lib.i2d_DHparams_bio else: raise TypeError("encoding must be an item from the Encoding enum") bio = self._create_mem_bio_gc() res = write_bio(bio, cdata) self.openssl_assert(res == 1) return self._read_mem_bio(bio) def generate_dh_parameters(self, generator, key_size): if key_size < 512: raise ValueError("DH key_size must be at least 512 bits") if generator not in (2, 5): raise ValueError("DH generator must be 2 or 5") dh_param_cdata = self._lib.DH_new() self.openssl_assert(dh_param_cdata != self._ffi.NULL) dh_param_cdata = self._ffi.gc(dh_param_cdata, self._lib.DH_free) res = self._lib.DH_generate_parameters_ex( dh_param_cdata, key_size, generator, self._ffi.NULL ) self.openssl_assert(res == 1) return _DHParameters(self, dh_param_cdata) def _dh_cdata_to_evp_pkey(self, dh_cdata): evp_pkey = self._create_evp_pkey_gc() res = self._lib.EVP_PKEY_set1_DH(evp_pkey, dh_cdata) self.openssl_assert(res == 1) return evp_pkey def generate_dh_private_key(self, parameters): dh_key_cdata = _dh_params_dup(parameters._dh_cdata, self) res = self._lib.DH_generate_key(dh_key_cdata) self.openssl_assert(res == 1) evp_pkey = self._dh_cdata_to_evp_pkey(dh_key_cdata) return _DHPrivateKey(self, dh_key_cdata, evp_pkey) def generate_dh_private_key_and_parameters(self, generator, key_size): return self.generate_dh_private_key( self.generate_dh_parameters(generator, key_size) ) def load_dh_private_numbers(self, numbers): parameter_numbers = numbers.public_numbers.parameter_numbers dh_cdata = self._lib.DH_new() self.openssl_assert(dh_cdata != self._ffi.NULL) dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free) p = self._int_to_bn(parameter_numbers.p) g = self._int_to_bn(parameter_numbers.g) if parameter_numbers.q is not None: q = self._int_to_bn(parameter_numbers.q) else: q = self._ffi.NULL pub_key = self._int_to_bn(numbers.public_numbers.y) priv_key = self._int_to_bn(numbers.x) res = self._lib.DH_set0_pqg(dh_cdata, p, q, g) self.openssl_assert(res == 1) res = self._lib.DH_set0_key(dh_cdata, pub_key, priv_key) self.openssl_assert(res == 1) codes = self._ffi.new("int[]", 1) res = self._lib.Cryptography_DH_check(dh_cdata, codes) self.openssl_assert(res == 1) # DH_check will return DH_NOT_SUITABLE_GENERATOR if p % 24 does not # equal 11 when the generator is 2 (a quadratic nonresidue). # We want to ignore that error because p % 24 == 23 is also fine. # Specifically, g is then a quadratic residue. Within the context of # Diffie-Hellman this means it can only generate half the possible # values. That sounds bad, but quadratic nonresidues leak a bit of # the key to the attacker in exchange for having the full key space # available. See: https://crypto.stackexchange.com/questions/12961 if codes[0] != 0 and not ( parameter_numbers.g == 2 and codes[0] ^ self._lib.DH_NOT_SUITABLE_GENERATOR == 0 ): raise ValueError("DH private numbers did not pass safety checks.") evp_pkey = self._dh_cdata_to_evp_pkey(dh_cdata) return _DHPrivateKey(self, dh_cdata, evp_pkey) def load_dh_public_numbers(self, numbers): dh_cdata = self._lib.DH_new() self.openssl_assert(dh_cdata != self._ffi.NULL) dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free) parameter_numbers = numbers.parameter_numbers p = self._int_to_bn(parameter_numbers.p) g = self._int_to_bn(parameter_numbers.g) if parameter_numbers.q is not None: q = self._int_to_bn(parameter_numbers.q) else: q = self._ffi.NULL pub_key = self._int_to_bn(numbers.y) res = self._lib.DH_set0_pqg(dh_cdata, p, q, g) self.openssl_assert(res == 1) res = self._lib.DH_set0_key(dh_cdata, pub_key, self._ffi.NULL) self.openssl_assert(res == 1) evp_pkey = self._dh_cdata_to_evp_pkey(dh_cdata) return _DHPublicKey(self, dh_cdata, evp_pkey) def load_dh_parameter_numbers(self, numbers): dh_cdata = self._lib.DH_new() self.openssl_assert(dh_cdata != self._ffi.NULL) dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free) p = self._int_to_bn(numbers.p) g = self._int_to_bn(numbers.g) if numbers.q is not None: q = self._int_to_bn(numbers.q) else: q = self._ffi.NULL res = self._lib.DH_set0_pqg(dh_cdata, p, q, g) self.openssl_assert(res == 1) return _DHParameters(self, dh_cdata) def dh_parameters_supported(self, p, g, q=None): dh_cdata = self._lib.DH_new() self.openssl_assert(dh_cdata != self._ffi.NULL) dh_cdata = self._ffi.gc(dh_cdata, self._lib.DH_free) p = self._int_to_bn(p) g = self._int_to_bn(g) if q is not None: q = self._int_to_bn(q) else: q = self._ffi.NULL res = self._lib.DH_set0_pqg(dh_cdata, p, q, g) self.openssl_assert(res == 1) codes = self._ffi.new("int[]", 1) res = self._lib.Cryptography_DH_check(dh_cdata, codes) self.openssl_assert(res == 1) return codes[0] == 0 def dh_x942_serialization_supported(self): return self._lib.Cryptography_HAS_EVP_PKEY_DHX == 1 def x509_name_bytes(self, name): x509_name = _encode_name_gc(self, name) pp = self._ffi.new("unsigned char **") res = self._lib.i2d_X509_NAME(x509_name, pp) self.openssl_assert(pp[0] != self._ffi.NULL) pp = self._ffi.gc( pp, lambda pointer: self._lib.OPENSSL_free(pointer[0]) ) self.openssl_assert(res > 0) return self._ffi.buffer(pp[0], res)[:] def x25519_load_public_bytes(self, data): # When we drop support for CRYPTOGRAPHY_OPENSSL_LESS_THAN_111 we can # switch this to EVP_PKEY_new_raw_public_key if len(data) != 32: raise ValueError("An X25519 public key is 32 bytes long") evp_pkey = self._create_evp_pkey_gc() res = self._lib.EVP_PKEY_set_type(evp_pkey, self._lib.NID_X25519) self.openssl_assert(res == 1) res = self._lib.EVP_PKEY_set1_tls_encodedpoint( evp_pkey, data, len(data) ) self.openssl_assert(res == 1) return _X25519PublicKey(self, evp_pkey) def x25519_load_private_bytes(self, data): # When we drop support for CRYPTOGRAPHY_OPENSSL_LESS_THAN_111 we can # switch this to EVP_PKEY_new_raw_private_key and drop the # zeroed_bytearray garbage. # OpenSSL only has facilities for loading PKCS8 formatted private # keys using the algorithm identifiers specified in # https://tools.ietf.org/html/draft-ietf-curdle-pkix-09. # This is the standard PKCS8 prefix for a 32 byte X25519 key. # The form is: # 0:d=0 hl=2 l= 46 cons: SEQUENCE # 2:d=1 hl=2 l= 1 prim: INTEGER :00 # 5:d=1 hl=2 l= 5 cons: SEQUENCE # 7:d=2 hl=2 l= 3 prim: OBJECT :1.3.101.110 # 12:d=1 hl=2 l= 34 prim: OCTET STRING (the key) # Of course there's a bit more complexity. In reality OCTET STRING # contains an OCTET STRING of length 32! So the last two bytes here # are \x04\x20, which is an OCTET STRING of length 32. if len(data) != 32: raise ValueError("An X25519 private key is 32 bytes long") pkcs8_prefix = b'0.\x02\x01\x000\x05\x06\x03+en\x04"\x04 ' with self._zeroed_bytearray(48) as ba: ba[0:16] = pkcs8_prefix ba[16:] = data bio = self._bytes_to_bio(ba) evp_pkey = self._lib.d2i_PrivateKey_bio(bio.bio, self._ffi.NULL) self.openssl_assert(evp_pkey != self._ffi.NULL) evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free) self.openssl_assert( self._lib.EVP_PKEY_id(evp_pkey) == self._lib.EVP_PKEY_X25519 ) return _X25519PrivateKey(self, evp_pkey) def _evp_pkey_keygen_gc(self, nid): evp_pkey_ctx = self._lib.EVP_PKEY_CTX_new_id(nid, self._ffi.NULL) self.openssl_assert(evp_pkey_ctx != self._ffi.NULL) evp_pkey_ctx = self._ffi.gc(evp_pkey_ctx, self._lib.EVP_PKEY_CTX_free) res = self._lib.EVP_PKEY_keygen_init(evp_pkey_ctx) self.openssl_assert(res == 1) evp_ppkey = self._ffi.new("EVP_PKEY **") res = self._lib.EVP_PKEY_keygen(evp_pkey_ctx, evp_ppkey) self.openssl_assert(res == 1) self.openssl_assert(evp_ppkey[0] != self._ffi.NULL) evp_pkey = self._ffi.gc(evp_ppkey[0], self._lib.EVP_PKEY_free) return evp_pkey def x25519_generate_key(self): evp_pkey = self._evp_pkey_keygen_gc(self._lib.NID_X25519) return _X25519PrivateKey(self, evp_pkey) def x25519_supported(self): if self._fips_enabled: return False return self._lib.CRYPTOGRAPHY_OPENSSL_110_OR_GREATER def x448_load_public_bytes(self, data): if len(data) != 56: raise ValueError("An X448 public key is 56 bytes long") evp_pkey = self._lib.EVP_PKEY_new_raw_public_key( self._lib.NID_X448, self._ffi.NULL, data, len(data) ) self.openssl_assert(evp_pkey != self._ffi.NULL) evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free) return _X448PublicKey(self, evp_pkey) def x448_load_private_bytes(self, data): if len(data) != 56: raise ValueError("An X448 private key is 56 bytes long") data_ptr = self._ffi.from_buffer(data) evp_pkey = self._lib.EVP_PKEY_new_raw_private_key( self._lib.NID_X448, self._ffi.NULL, data_ptr, len(data) ) self.openssl_assert(evp_pkey != self._ffi.NULL) evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free) return _X448PrivateKey(self, evp_pkey) def x448_generate_key(self): evp_pkey = self._evp_pkey_keygen_gc(self._lib.NID_X448) return _X448PrivateKey(self, evp_pkey) def x448_supported(self): if self._fips_enabled: return False return not self._lib.CRYPTOGRAPHY_OPENSSL_LESS_THAN_111 def ed25519_supported(self): if self._fips_enabled: return False return not self._lib.CRYPTOGRAPHY_OPENSSL_LESS_THAN_111B def ed25519_load_public_bytes(self, data): utils._check_bytes("data", data) if len(data) != ed25519._ED25519_KEY_SIZE: raise ValueError("An Ed25519 public key is 32 bytes long") evp_pkey = self._lib.EVP_PKEY_new_raw_public_key( self._lib.NID_ED25519, self._ffi.NULL, data, len(data) ) self.openssl_assert(evp_pkey != self._ffi.NULL) evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free) return _Ed25519PublicKey(self, evp_pkey) def ed25519_load_private_bytes(self, data): if len(data) != ed25519._ED25519_KEY_SIZE: raise ValueError("An Ed25519 private key is 32 bytes long") utils._check_byteslike("data", data) data_ptr = self._ffi.from_buffer(data) evp_pkey = self._lib.EVP_PKEY_new_raw_private_key( self._lib.NID_ED25519, self._ffi.NULL, data_ptr, len(data) ) self.openssl_assert(evp_pkey != self._ffi.NULL) evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free) return _Ed25519PrivateKey(self, evp_pkey) def ed25519_generate_key(self): evp_pkey = self._evp_pkey_keygen_gc(self._lib.NID_ED25519) return _Ed25519PrivateKey(self, evp_pkey) def ed448_supported(self): if self._fips_enabled: return False return not self._lib.CRYPTOGRAPHY_OPENSSL_LESS_THAN_111B def ed448_load_public_bytes(self, data): utils._check_bytes("data", data) if len(data) != _ED448_KEY_SIZE: raise ValueError("An Ed448 public key is 57 bytes long") evp_pkey = self._lib.EVP_PKEY_new_raw_public_key( self._lib.NID_ED448, self._ffi.NULL, data, len(data) ) self.openssl_assert(evp_pkey != self._ffi.NULL) evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free) return _Ed448PublicKey(self, evp_pkey) def ed448_load_private_bytes(self, data): utils._check_byteslike("data", data) if len(data) != _ED448_KEY_SIZE: raise ValueError("An Ed448 private key is 57 bytes long") data_ptr = self._ffi.from_buffer(data) evp_pkey = self._lib.EVP_PKEY_new_raw_private_key( self._lib.NID_ED448, self._ffi.NULL, data_ptr, len(data) ) self.openssl_assert(evp_pkey != self._ffi.NULL) evp_pkey = self._ffi.gc(evp_pkey, self._lib.EVP_PKEY_free) return _Ed448PrivateKey(self, evp_pkey) def ed448_generate_key(self): evp_pkey = self._evp_pkey_keygen_gc(self._lib.NID_ED448) return _Ed448PrivateKey(self, evp_pkey) def derive_scrypt(self, key_material, salt, length, n, r, p): buf = self._ffi.new("unsigned char[]", length) key_material_ptr = self._ffi.from_buffer(key_material) res = self._lib.EVP_PBE_scrypt( key_material_ptr, len(key_material), salt, len(salt), n, r, p, scrypt._MEM_LIMIT, buf, length, ) if res != 1: errors = self._consume_errors_with_text() # memory required formula explained here: # https://blog.filippo.io/the-scrypt-parameters/ min_memory = 128 * n * r // (1024 ** 2) raise MemoryError( "Not enough memory to derive key. These parameters require" " {} MB of memory.".format(min_memory), errors, ) return self._ffi.buffer(buf)[:] def aead_cipher_supported(self, cipher): cipher_name = aead._aead_cipher_name(cipher) if self._fips_enabled and cipher_name not in self._fips_aead: return False return self._lib.EVP_get_cipherbyname(cipher_name) != self._ffi.NULL @contextlib.contextmanager def _zeroed_bytearray(self, length): """ This method creates a bytearray, which we copy data into (hopefully also from a mutable buffer that can be dynamically erased!), and then zero when we're done. """ ba = bytearray(length) try: yield ba finally: self._zero_data(ba, length) def _zero_data(self, data, length): # We clear things this way because at the moment we're not # sure of a better way that can guarantee it overwrites the # memory of a bytearray and doesn't just replace the underlying char *. for i in range(length): data[i] = 0 @contextlib.contextmanager def _zeroed_null_terminated_buf(self, data): """ This method takes bytes, which can be a bytestring or a mutable buffer like a bytearray, and yields a null-terminated version of that data. This is required because PKCS12_parse doesn't take a length with its password char * and ffi.from_buffer doesn't provide null termination. So, to support zeroing the data via bytearray we need to build this ridiculous construct that copies the memory, but zeroes it after use. """ if data is None: yield self._ffi.NULL else: data_len = len(data) buf = self._ffi.new("char[]", data_len + 1) self._ffi.memmove(buf, data, data_len) try: yield buf finally: # Cast to a uint8_t * so we can assign by integer self._zero_data(self._ffi.cast("uint8_t *", buf), data_len) def load_key_and_certificates_from_pkcs12(self, data, password): if password is not None: utils._check_byteslike("password", password) bio = self._bytes_to_bio(data) p12 = self._lib.d2i_PKCS12_bio(bio.bio, self._ffi.NULL) if p12 == self._ffi.NULL: self._consume_errors() raise ValueError("Could not deserialize PKCS12 data") p12 = self._ffi.gc(p12, self._lib.PKCS12_free) evp_pkey_ptr = self._ffi.new("EVP_PKEY **") x509_ptr = self._ffi.new("X509 **") sk_x509_ptr = self._ffi.new("Cryptography_STACK_OF_X509 **") with self._zeroed_null_terminated_buf(password) as password_buf: res = self._lib.PKCS12_parse( p12, password_buf, evp_pkey_ptr, x509_ptr, sk_x509_ptr ) if res == 0: self._consume_errors() raise ValueError("Invalid password or PKCS12 data") cert = None key = None additional_certificates = [] if evp_pkey_ptr[0] != self._ffi.NULL: evp_pkey = self._ffi.gc(evp_pkey_ptr[0], self._lib.EVP_PKEY_free) key = self._evp_pkey_to_private_key(evp_pkey) if x509_ptr[0] != self._ffi.NULL: x509 = self._ffi.gc(x509_ptr[0], self._lib.X509_free) cert = _Certificate(self, x509) if sk_x509_ptr[0] != self._ffi.NULL: sk_x509 = self._ffi.gc(sk_x509_ptr[0], self._lib.sk_X509_free) num = self._lib.sk_X509_num(sk_x509_ptr[0]) for i in range(num): x509 = self._lib.sk_X509_value(sk_x509, i) self.openssl_assert(x509 != self._ffi.NULL) x509 = self._ffi.gc(x509, self._lib.X509_free) additional_certificates.append(_Certificate(self, x509)) return (key, cert, additional_certificates) def serialize_key_and_certificates_to_pkcs12( self, name, key, cert, cas, encryption_algorithm ): password = None if name is not None: utils._check_bytes("name", name) if isinstance(encryption_algorithm, serialization.NoEncryption): nid_cert = -1 nid_key = -1 pkcs12_iter = 0 mac_iter = 0 elif isinstance( encryption_algorithm, serialization.BestAvailableEncryption ): # PKCS12 encryption is hopeless trash and can never be fixed. # This is the least terrible option. nid_cert = self._lib.NID_pbe_WithSHA1And3_Key_TripleDES_CBC nid_key = self._lib.NID_pbe_WithSHA1And3_Key_TripleDES_CBC # At least we can set this higher than OpenSSL's default pkcs12_iter = 20000 # mac_iter chosen for compatibility reasons, see: # https://www.openssl.org/docs/man1.1.1/man3/PKCS12_create.html # Did we mention how lousy PKCS12 encryption is? mac_iter = 1 password = encryption_algorithm.password else: raise ValueError("Unsupported key encryption type") if cas is None or len(cas) == 0: sk_x509 = self._ffi.NULL else: sk_x509 = self._lib.sk_X509_new_null() sk_x509 = self._ffi.gc(sk_x509, self._lib.sk_X509_free) # reverse the list when building the stack so that they're encoded # in the order they were originally provided. it is a mystery for ca in reversed(cas): res = self._lib.sk_X509_push(sk_x509, ca._x509) backend.openssl_assert(res >= 1) with self._zeroed_null_terminated_buf(password) as password_buf: with self._zeroed_null_terminated_buf(name) as name_buf: p12 = self._lib.PKCS12_create( password_buf, name_buf, key._evp_pkey if key else self._ffi.NULL, cert._x509 if cert else self._ffi.NULL, sk_x509, nid_key, nid_cert, pkcs12_iter, mac_iter, 0, ) self.openssl_assert(p12 != self._ffi.NULL) p12 = self._ffi.gc(p12, self._lib.PKCS12_free) bio = self._create_mem_bio_gc() res = self._lib.i2d_PKCS12_bio(bio, p12) self.openssl_assert(res > 0) return self._read_mem_bio(bio) def poly1305_supported(self): if self._fips_enabled: return False return self._lib.Cryptography_HAS_POLY1305 == 1 def create_poly1305_ctx(self, key): utils._check_byteslike("key", key) if len(key) != _POLY1305_KEY_SIZE: raise ValueError("A poly1305 key is 32 bytes long") return _Poly1305Context(self, key) def load_pem_pkcs7_certificates(self, data): utils._check_bytes("data", data) bio = self._bytes_to_bio(data) p7 = self._lib.PEM_read_bio_PKCS7( bio.bio, self._ffi.NULL, self._ffi.NULL, self._ffi.NULL ) if p7 == self._ffi.NULL: self._consume_errors() raise ValueError("Unable to parse PKCS7 data") p7 = self._ffi.gc(p7, self._lib.PKCS7_free) return self._load_pkcs7_certificates(p7) def load_der_pkcs7_certificates(self, data): utils._check_bytes("data", data) bio = self._bytes_to_bio(data) p7 = self._lib.d2i_PKCS7_bio(bio.bio, self._ffi.NULL) if p7 == self._ffi.NULL: self._consume_errors() raise ValueError("Unable to parse PKCS7 data") p7 = self._ffi.gc(p7, self._lib.PKCS7_free) return self._load_pkcs7_certificates(p7) def _load_pkcs7_certificates(self, p7): nid = self._lib.OBJ_obj2nid(p7.type) self.openssl_assert(nid != self._lib.NID_undef) if nid != self._lib.NID_pkcs7_signed: raise UnsupportedAlgorithm( "Only basic signed structures are currently supported. NID" " for this data was {}".format(nid), _Reasons.UNSUPPORTED_SERIALIZATION, ) sk_x509 = p7.d.sign.cert num = self._lib.sk_X509_num(sk_x509) certs = [] for i in range(num): x509 = self._lib.sk_X509_value(sk_x509, i) self.openssl_assert(x509 != self._ffi.NULL) res = self._lib.X509_up_ref(x509) # When OpenSSL is less than 1.1.0 up_ref returns the current # refcount. On 1.1.0+ it returns 1 for success. self.openssl_assert(res >= 1) x509 = self._ffi.gc(x509, self._lib.X509_free) certs.append(_Certificate(self, x509)) return certs def pkcs7_sign(self, builder, encoding, options): bio = self._bytes_to_bio(builder._data) init_flags = self._lib.PKCS7_PARTIAL final_flags = 0 if len(builder._additional_certs) == 0: certs = self._ffi.NULL else: certs = self._lib.sk_X509_new_null() certs = self._ffi.gc(certs, self._lib.sk_X509_free) for cert in builder._additional_certs: res = self._lib.sk_X509_push(certs, cert._x509) self.openssl_assert(res >= 1) if pkcs7.PKCS7Options.DetachedSignature in options: # Don't embed the data in the PKCS7 structure init_flags |= self._lib.PKCS7_DETACHED final_flags |= self._lib.PKCS7_DETACHED # This just inits a structure for us. However, there # are flags we need to set, joy. p7 = self._lib.PKCS7_sign( self._ffi.NULL, self._ffi.NULL, certs, self._ffi.NULL, init_flags, ) self.openssl_assert(p7 != self._ffi.NULL) p7 = self._ffi.gc(p7, self._lib.PKCS7_free) signer_flags = 0 # These flags are configurable on a per-signature basis # but we've deliberately chosen to make the API only allow # setting it across all signatures for now. if pkcs7.PKCS7Options.NoCapabilities in options: signer_flags |= self._lib.PKCS7_NOSMIMECAP elif pkcs7.PKCS7Options.NoAttributes in options: signer_flags |= self._lib.PKCS7_NOATTR if pkcs7.PKCS7Options.NoCerts in options: signer_flags |= self._lib.PKCS7_NOCERTS for certificate, private_key, hash_algorithm in builder._signers: md = self._evp_md_non_null_from_algorithm(hash_algorithm) p7signerinfo = self._lib.PKCS7_sign_add_signer( p7, certificate._x509, private_key._evp_pkey, md, signer_flags ) self.openssl_assert(p7signerinfo != self._ffi.NULL) for option in options: # DetachedSignature, NoCapabilities, and NoAttributes are already # handled so we just need to check these last two options. if option is pkcs7.PKCS7Options.Text: final_flags |= self._lib.PKCS7_TEXT elif option is pkcs7.PKCS7Options.Binary: final_flags |= self._lib.PKCS7_BINARY bio_out = self._create_mem_bio_gc() if encoding is serialization.Encoding.SMIME: # This finalizes the structure res = self._lib.SMIME_write_PKCS7( bio_out, p7, bio.bio, final_flags ) elif encoding is serialization.Encoding.PEM: res = self._lib.PKCS7_final(p7, bio.bio, final_flags) self.openssl_assert(res == 1) res = self._lib.PEM_write_bio_PKCS7_stream( bio_out, p7, bio.bio, final_flags ) else: assert encoding is serialization.Encoding.DER # We need to call finalize here becauase i2d_PKCS7_bio does not # finalize. res = self._lib.PKCS7_final(p7, bio.bio, final_flags) self.openssl_assert(res == 1) res = self._lib.i2d_PKCS7_bio(bio_out, p7) self.openssl_assert(res == 1) return self._read_mem_bio(bio_out) 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")) def _get_xts_cipher(backend, cipher, mode): cipher_name = "aes-{}-xts".format(cipher.key_size // 2) return backend._lib.EVP_get_cipherbyname(cipher_name.encode("ascii")) backend = Backend()