# Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or # implied. # See the License for the specific language governing permissions and # limitations under the License. from __future__ import absolute_import, division, print_function import collections import itertools import warnings from contextlib import contextmanager import six from cryptography import utils from cryptography.exceptions import ( InternalError, UnsupportedAlgorithm, _Reasons ) from cryptography.hazmat.backends.interfaces import ( CMACBackend, CipherBackend, DSABackend, EllipticCurveBackend, HMACBackend, HashBackend, PBKDF2HMACBackend, PEMSerializationBackend, PKCS8SerializationBackend, RSABackend, TraditionalOpenSSLSerializationBackend ) 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, _DSASignatureContext, _DSAVerificationContext ) 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, _RSASignatureContext, _RSAVerificationContext ) from cryptography.hazmat.bindings.openssl.binding import Binding from cryptography.hazmat.primitives import hashes 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"]) @utils.register_interface(CipherBackend) @utils.register_interface(CMACBackend) @utils.register_interface(DSABackend) @utils.register_interface(EllipticCurveBackend) @utils.register_interface(HashBackend) @utils.register_interface(HMACBackend) @utils.register_interface(PBKDF2HMACBackend) @utils.register_interface(PKCS8SerializationBackend) @utils.register_interface(RSABackend) @utils.register_interface(TraditionalOpenSSLSerializationBackend) @utils.register_interface(PEMSerializationBackend) 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._lib.Cryptography_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): 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) 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. """ 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 return _RSAPrivateKey(self, rsa_cdata) 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 return _RSAPrivateKey(self, rsa_cdata) 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 return _RSAPublicKey(self, rsa_cdata) 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 _evp_pkey_to_private_key(self, evp_pkey): """ Return the appropriate type of PrivateKey given an evp_pkey cdata pointer. """ type = evp_pkey.type if 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) elif 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) elif (self._lib.Cryptography_HAS_EC == 1 and 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) 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. """ type = evp_pkey.type if 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) elif 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) elif (self._lib.Cryptography_HAS_EC == 1 and 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) 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 _rsa_cdata_from_private_key(self, private_key): ctx = self._lib.RSA_new() assert ctx != self._ffi.NULL ctx = self._ffi.gc(ctx, self._lib.RSA_free) ctx.p = self._int_to_bn(private_key.p) ctx.q = self._int_to_bn(private_key.q) ctx.d = self._int_to_bn(private_key.d) ctx.e = self._int_to_bn(private_key.e) ctx.n = self._int_to_bn(private_key.n) ctx.dmp1 = self._int_to_bn(private_key.dmp1) ctx.dmq1 = self._int_to_bn(private_key.dmq1) ctx.iqmp = self._int_to_bn(private_key.iqmp) res = self._lib.RSA_blinding_on(ctx, self._ffi.NULL) assert res == 1 return ctx def _rsa_cdata_from_public_key(self, public_key): ctx = self._lib.RSA_new() assert ctx != self._ffi.NULL ctx = self._ffi.gc(ctx, self._lib.RSA_free) ctx.e = self._int_to_bn(public_key.e) ctx.n = self._int_to_bn(public_key.n) res = self._lib.RSA_blinding_on(ctx, self._ffi.NULL) assert res == 1 return ctx def create_rsa_signature_ctx(self, private_key, padding, algorithm): warnings.warn( "create_rsa_signature_ctx is deprecated and will be removed in a " "future version.", utils.DeprecatedIn05, stacklevel=2 ) rsa_cdata = self._rsa_cdata_from_private_key(private_key) key = _RSAPrivateKey(self, rsa_cdata) return _RSASignatureContext(self, key, padding, algorithm) def create_rsa_verification_ctx(self, public_key, signature, padding, algorithm): warnings.warn( "create_rsa_verification_ctx is deprecated and will be removed in " "a future version.", utils.DeprecatedIn05, stacklevel=2 ) rsa_cdata = self._rsa_cdata_from_public_key(public_key) key = _RSAPublicKey(self, rsa_cdata) return _RSAVerificationContext(self, key, signature, padding, algorithm) def mgf1_hash_supported(self, algorithm): warnings.warn( "mgf1_hash_supported is deprecated and will be removed in " "a future version.", utils.DeprecatedIn05, stacklevel=2 ) return self._mgf1_hash_supported(algorithm) 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) if isinstance(parameters, dsa.DSAParameters): ctx.p = self._int_to_bn(parameters.p) ctx.q = self._int_to_bn(parameters.q) ctx.g = self._int_to_bn(parameters.g) else: 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) return _DSAPrivateKey(self, ctx) 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 create_dsa_signature_ctx(self, private_key, algorithm): warnings.warn( "create_dsa_signature_ctx is deprecated and will be removed in " "a future version.", utils.DeprecatedIn05, stacklevel=2 ) dsa_cdata = self._dsa_cdata_from_private_key(private_key) key = _DSAPrivateKey(self, dsa_cdata) return _DSASignatureContext(self, key, algorithm) def create_dsa_verification_ctx(self, public_key, signature, algorithm): warnings.warn( "create_dsa_verification_ctx is deprecated and will be removed in " "a future version.", utils.DeprecatedIn05, stacklevel=2 ) dsa_cdata = self._dsa_cdata_from_public_key(public_key) key = _DSAPublicKey(self, dsa_cdata) return _DSAVerificationContext(self, key, signature, algorithm) 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) return _DSAPrivateKey(self, dsa_cdata) 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) return _DSAPublicKey(self, dsa_cdata) 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_from_public_key(self, public_key): ctx = self._lib.DSA_new() assert ctx != self._ffi.NULL ctx = self._ffi.gc(ctx, self._lib.DSA_free) parameters = public_key.parameters() ctx.p = self._int_to_bn(parameters.p) ctx.q = self._int_to_bn(parameters.q) ctx.g = self._int_to_bn(parameters.g) ctx.pub_key = self._int_to_bn(public_key.y) return ctx def _dsa_cdata_from_private_key(self, private_key): ctx = self._lib.DSA_new() assert ctx != self._ffi.NULL ctx = self._ffi.gc(ctx, self._lib.DSA_free) parameters = private_key.parameters() ctx.p = self._int_to_bn(parameters.p) ctx.q = self._int_to_bn(parameters.q) ctx.g = self._int_to_bn(parameters.g) ctx.priv_key = self._int_to_bn(private_key.x) ctx.pub_key = self._int_to_bn(private_key.y) return ctx 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 decrypt_rsa(self, private_key, ciphertext, padding): warnings.warn( "decrypt_rsa is deprecated and will be removed in a future " "version.", utils.DeprecatedIn05, stacklevel=2 ) rsa_cdata = self._rsa_cdata_from_private_key(private_key) key = _RSAPrivateKey(self, rsa_cdata) return key.decrypt(ciphertext, padding) def encrypt_rsa(self, public_key, plaintext, padding): warnings.warn( "encrypt_rsa is deprecated and will be removed in a future " "version.", utils.DeprecatedIn05, stacklevel=2 ) rsa_cdata = self._rsa_cdata_from_public_key(public_key) key = _RSAPublicKey(self, rsa_cdata) return key.encrypt(plaintext, padding) 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 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): return self._load_key( self._lib.PEM_read_bio_PUBKEY, self._evp_pkey_to_public_key, data, None, ) def load_traditional_openssl_pem_private_key(self, data, password): warnings.warn( "load_traditional_openssl_pem_private_key is deprecated and will " "be removed in a future version, use load_pem_private_key " "instead.", utils.DeprecatedIn06, stacklevel=2 ) return self.load_pem_private_key(data, password) def load_pkcs8_pem_private_key(self, data, password): warnings.warn( "load_pkcs8_pem_private_key is deprecated and will be removed in a" " future version, use load_pem_private_key instead.", utils.DeprecatedIn06, stacklevel=2 ) return self.load_pem_private_key(data, password) 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 return _EllipticCurvePrivateKey(self, ec_cdata) else: raise UnsupportedAlgorithm( "Backend object does not support {0}.".format(curve.name), _Reasons.UNSUPPORTED_ELLIPTIC_CURVE ) def elliptic_curve_private_key_from_numbers(self, numbers): warnings.warn( "elliptic_curve_private_key_from_numbers is deprecated and will " "be removed in a future version.", utils.DeprecatedIn06, stacklevel=2 ) return self.load_elliptic_curve_private_numbers(numbers) 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 return _EllipticCurvePrivateKey(self, ec_cdata) def elliptic_curve_public_key_from_numbers(self, numbers): warnings.warn( "elliptic_curve_public_key_from_numbers is deprecated and will be " "removed in a future version.", utils.DeprecatedIn06, stacklevel=2 ) return self.load_elliptic_curve_public_numbers(numbers) 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) return _EllipticCurvePublicKey(self, ec_cdata) 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. """ bn_x = self._int_to_bn(x) bn_y = self._int_to_bn(y) 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) 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 assert ( self._lib.BN_cmp(bn_x, check_x) == 0 and self._lib.BN_cmp(bn_y, check_y) == 0 ) res = self._lib.EC_KEY_set_public_key(ctx, point) assert res == 1 res = self._lib.EC_KEY_check_key(ctx) assert res == 1 return ctx 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()