# 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 from cryptography import utils from cryptography.exceptions import ( InvalidSignature, UnsupportedAlgorithm, _Reasons ) from cryptography.hazmat.backends.openssl.utils import ( _calculate_digest_and_algorithm, _check_not_prehashed, _warn_sign_verify_deprecated ) from cryptography.hazmat.primitives import hashes from cryptography.hazmat.primitives.asymmetric import ( AsymmetricSignatureContext, AsymmetricVerificationContext, rsa ) from cryptography.hazmat.primitives.asymmetric.padding import ( AsymmetricPadding, MGF1, OAEP, PKCS1v15, PSS, calculate_max_pss_salt_length ) from cryptography.hazmat.primitives.asymmetric.rsa import ( RSAPrivateKeyWithSerialization, RSAPublicKeyWithSerialization ) def _get_rsa_pss_salt_length(pss, key, hash_algorithm): salt = pss._salt_length if salt is MGF1.MAX_LENGTH or salt is PSS.MAX_LENGTH: return calculate_max_pss_salt_length(key, hash_algorithm) else: return salt def _enc_dec_rsa(backend, key, data, padding): if not isinstance(padding, AsymmetricPadding): raise TypeError("Padding must be an instance of AsymmetricPadding.") if isinstance(padding, PKCS1v15): padding_enum = backend._lib.RSA_PKCS1_PADDING elif isinstance(padding, OAEP): padding_enum = backend._lib.RSA_PKCS1_OAEP_PADDING if not isinstance(padding._mgf, MGF1): raise UnsupportedAlgorithm( "Only MGF1 is supported by this backend.", _Reasons.UNSUPPORTED_MGF ) if not backend.rsa_padding_supported(padding): raise UnsupportedAlgorithm( "This combination of padding and hash algorithm is not " "supported by this backend.", _Reasons.UNSUPPORTED_PADDING ) else: raise UnsupportedAlgorithm( "{} is not supported by this backend.".format( padding.name ), _Reasons.UNSUPPORTED_PADDING ) return _enc_dec_rsa_pkey_ctx(backend, key, data, padding_enum, padding) def _enc_dec_rsa_pkey_ctx(backend, key, data, padding_enum, padding): if isinstance(key, _RSAPublicKey): init = backend._lib.EVP_PKEY_encrypt_init crypt = backend._lib.EVP_PKEY_encrypt else: init = backend._lib.EVP_PKEY_decrypt_init crypt = backend._lib.EVP_PKEY_decrypt pkey_ctx = backend._lib.EVP_PKEY_CTX_new( key._evp_pkey, backend._ffi.NULL ) backend.openssl_assert(pkey_ctx != backend._ffi.NULL) pkey_ctx = backend._ffi.gc(pkey_ctx, backend._lib.EVP_PKEY_CTX_free) res = init(pkey_ctx) backend.openssl_assert(res == 1) res = backend._lib.EVP_PKEY_CTX_set_rsa_padding( pkey_ctx, padding_enum) backend.openssl_assert(res > 0) buf_size = backend._lib.EVP_PKEY_size(key._evp_pkey) backend.openssl_assert(buf_size > 0) if ( isinstance(padding, OAEP) and backend._lib.Cryptography_HAS_RSA_OAEP_MD ): mgf1_md = backend._evp_md_non_null_from_algorithm( padding._mgf._algorithm) res = backend._lib.EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, mgf1_md) backend.openssl_assert(res > 0) oaep_md = backend._evp_md_non_null_from_algorithm(padding._algorithm) res = backend._lib.EVP_PKEY_CTX_set_rsa_oaep_md(pkey_ctx, oaep_md) backend.openssl_assert(res > 0) if ( isinstance(padding, OAEP) and padding._label is not None and len(padding._label) > 0 ): # set0_rsa_oaep_label takes ownership of the char * so we need to # copy it into some new memory labelptr = backend._lib.OPENSSL_malloc(len(padding._label)) backend.openssl_assert(labelptr != backend._ffi.NULL) backend._ffi.memmove(labelptr, padding._label, len(padding._label)) res = backend._lib.EVP_PKEY_CTX_set0_rsa_oaep_label( pkey_ctx, labelptr, len(padding._label) ) backend.openssl_assert(res == 1) outlen = backend._ffi.new("size_t *", buf_size) buf = backend._ffi.new("unsigned char[]", buf_size) res = crypt(pkey_ctx, buf, outlen, data, len(data)) if res <= 0: _handle_rsa_enc_dec_error(backend, key) return backend._ffi.buffer(buf)[:outlen[0]] def _handle_rsa_enc_dec_error(backend, key): errors = backend._consume_errors() backend.openssl_assert(errors) backend.openssl_assert(errors[0].lib == backend._lib.ERR_LIB_RSA) if isinstance(key, _RSAPublicKey): backend.openssl_assert( errors[0].reason == backend._lib.RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE ) raise ValueError( "Data too long for key size. Encrypt less data or use a " "larger key size." ) else: decoding_errors = [ backend._lib.RSA_R_BAD_PAD_BYTE_COUNT, backend._lib.RSA_R_BLOCK_TYPE_IS_NOT_01, backend._lib.RSA_R_BLOCK_TYPE_IS_NOT_02, backend._lib.RSA_R_OAEP_DECODING_ERROR, # Though this error looks similar to the # RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE, this occurs on decrypts, # rather than on encrypts backend._lib.RSA_R_DATA_TOO_LARGE_FOR_MODULUS, ] if backend._lib.Cryptography_HAS_RSA_R_PKCS_DECODING_ERROR: decoding_errors.append(backend._lib.RSA_R_PKCS_DECODING_ERROR) backend.openssl_assert(errors[0].reason in decoding_errors) raise ValueError("Decryption failed.") def _rsa_sig_determine_padding(backend, key, padding, algorithm): if not isinstance(padding, AsymmetricPadding): raise TypeError("Expected provider of AsymmetricPadding.") pkey_size = backend._lib.EVP_PKEY_size(key._evp_pkey) backend.openssl_assert(pkey_size > 0) if isinstance(padding, PKCS1v15): padding_enum = backend._lib.RSA_PKCS1_PADDING elif isinstance(padding, PSS): if not isinstance(padding._mgf, MGF1): raise UnsupportedAlgorithm( "Only MGF1 is supported by this backend.", _Reasons.UNSUPPORTED_MGF ) # Size of key in bytes - 2 is the maximum # PSS signature length (salt length is checked later) if pkey_size - algorithm.digest_size - 2 < 0: raise ValueError("Digest too large for key size. Use a larger " "key or different digest.") padding_enum = backend._lib.RSA_PKCS1_PSS_PADDING else: raise UnsupportedAlgorithm( "{} is not supported by this backend.".format(padding.name), _Reasons.UNSUPPORTED_PADDING ) return padding_enum def _rsa_sig_setup(backend, padding, algorithm, key, data, init_func): padding_enum = _rsa_sig_determine_padding(backend, key, padding, algorithm) evp_md = backend._evp_md_non_null_from_algorithm(algorithm) pkey_ctx = backend._lib.EVP_PKEY_CTX_new(key._evp_pkey, backend._ffi.NULL) backend.openssl_assert(pkey_ctx != backend._ffi.NULL) pkey_ctx = backend._ffi.gc(pkey_ctx, backend._lib.EVP_PKEY_CTX_free) res = init_func(pkey_ctx) backend.openssl_assert(res == 1) res = backend._lib.EVP_PKEY_CTX_set_signature_md(pkey_ctx, evp_md) if res == 0: backend._consume_errors() raise UnsupportedAlgorithm( "{} is not supported by this backend for RSA signing.".format( algorithm.name ), _Reasons.UNSUPPORTED_HASH ) res = backend._lib.EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, padding_enum) backend.openssl_assert(res > 0) if isinstance(padding, PSS): res = backend._lib.EVP_PKEY_CTX_set_rsa_pss_saltlen( pkey_ctx, _get_rsa_pss_salt_length(padding, key, algorithm) ) backend.openssl_assert(res > 0) mgf1_md = backend._evp_md_non_null_from_algorithm( padding._mgf._algorithm) res = backend._lib.EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, mgf1_md) backend.openssl_assert(res > 0) return pkey_ctx def _rsa_sig_sign(backend, padding, algorithm, private_key, data): pkey_ctx = _rsa_sig_setup( backend, padding, algorithm, private_key, data, backend._lib.EVP_PKEY_sign_init ) buflen = backend._ffi.new("size_t *") res = backend._lib.EVP_PKEY_sign( pkey_ctx, backend._ffi.NULL, buflen, data, len(data) ) backend.openssl_assert(res == 1) buf = backend._ffi.new("unsigned char[]", buflen[0]) res = backend._lib.EVP_PKEY_sign( pkey_ctx, buf, buflen, data, len(data)) if res != 1: errors = backend._consume_errors() backend.openssl_assert(errors[0].lib == backend._lib.ERR_LIB_RSA) if ( errors[0].reason == backend._lib.RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE ): reason = ("Salt length too long for key size. Try using " "MAX_LENGTH instead.") else: backend.openssl_assert( errors[0].reason == backend._lib.RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY ) reason = "Digest too large for key size. Use a larger key." raise ValueError(reason) return backend._ffi.buffer(buf)[:] def _rsa_sig_verify(backend, padding, algorithm, public_key, signature, data): pkey_ctx = _rsa_sig_setup( backend, padding, algorithm, public_key, data, backend._lib.EVP_PKEY_verify_init ) res = backend._lib.EVP_PKEY_verify( pkey_ctx, signature, len(signature), data, len(data) ) # The previous call can return negative numbers in the event of an # error. This is not a signature failure but we need to fail if it # occurs. backend.openssl_assert(res >= 0) if res == 0: backend._consume_errors() raise InvalidSignature @utils.register_interface(AsymmetricSignatureContext) class _RSASignatureContext(object): def __init__(self, backend, private_key, padding, algorithm): self._backend = backend self._private_key = private_key # We now call _rsa_sig_determine_padding in _rsa_sig_setup. However # we need to make a pointless call to it here so we maintain the # API of erroring on init with this context if the values are invalid. _rsa_sig_determine_padding(backend, private_key, padding, algorithm) self._padding = padding self._algorithm = algorithm self._hash_ctx = hashes.Hash(self._algorithm, self._backend) def update(self, data): self._hash_ctx.update(data) def finalize(self): return _rsa_sig_sign( self._backend, self._padding, self._algorithm, self._private_key, self._hash_ctx.finalize() ) @utils.register_interface(AsymmetricVerificationContext) class _RSAVerificationContext(object): def __init__(self, backend, public_key, signature, padding, algorithm): self._backend = backend self._public_key = public_key self._signature = signature self._padding = padding # We now call _rsa_sig_determine_padding in _rsa_sig_setup. However # we need to make a pointless call to it here so we maintain the # API of erroring on init with this context if the values are invalid. _rsa_sig_determine_padding(backend, public_key, padding, algorithm) padding = padding self._algorithm = algorithm self._hash_ctx = hashes.Hash(self._algorithm, self._backend) def update(self, data): self._hash_ctx.update(data) def verify(self): return _rsa_sig_verify( self._backend, self._padding, self._algorithm, self._public_key, self._signature, self._hash_ctx.finalize() ) @utils.register_interface(RSAPrivateKeyWithSerialization) class _RSAPrivateKey(object): def __init__(self, backend, rsa_cdata, evp_pkey): self._backend = backend self._rsa_cdata = rsa_cdata self._evp_pkey = evp_pkey n = self._backend._ffi.new("BIGNUM **") self._backend._lib.RSA_get0_key( self._rsa_cdata, n, self._backend._ffi.NULL, self._backend._ffi.NULL ) self._backend.openssl_assert(n[0] != self._backend._ffi.NULL) self._key_size = self._backend._lib.BN_num_bits(n[0]) key_size = utils.read_only_property("_key_size") def signer(self, padding, algorithm): _warn_sign_verify_deprecated() _check_not_prehashed(algorithm) return _RSASignatureContext(self._backend, self, padding, algorithm) def decrypt(self, ciphertext, padding): key_size_bytes = (self.key_size + 7) // 8 if key_size_bytes != len(ciphertext): raise ValueError("Ciphertext length must be equal to key size.") return _enc_dec_rsa(self._backend, self, ciphertext, padding) def public_key(self): ctx = self._backend._lib.RSAPublicKey_dup(self._rsa_cdata) self._backend.openssl_assert(ctx != self._backend._ffi.NULL) ctx = self._backend._ffi.gc(ctx, self._backend._lib.RSA_free) res = self._backend._lib.RSA_blinding_on(ctx, self._backend._ffi.NULL) self._backend.openssl_assert(res == 1) evp_pkey = self._backend._rsa_cdata_to_evp_pkey(ctx) return _RSAPublicKey(self._backend, ctx, evp_pkey) def private_numbers(self): n = self._backend._ffi.new("BIGNUM **") e = self._backend._ffi.new("BIGNUM **") d = self._backend._ffi.new("BIGNUM **") p = self._backend._ffi.new("BIGNUM **") q = self._backend._ffi.new("BIGNUM **") dmp1 = self._backend._ffi.new("BIGNUM **") dmq1 = self._backend._ffi.new("BIGNUM **") iqmp = self._backend._ffi.new("BIGNUM **") self._backend._lib.RSA_get0_key(self._rsa_cdata, n, e, d) self._backend.openssl_assert(n[0] != self._backend._ffi.NULL) self._backend.openssl_assert(e[0] != self._backend._ffi.NULL) self._backend.openssl_assert(d[0] != self._backend._ffi.NULL) self._backend._lib.RSA_get0_factors(self._rsa_cdata, p, q) self._backend.openssl_assert(p[0] != self._backend._ffi.NULL) self._backend.openssl_assert(q[0] != self._backend._ffi.NULL) self._backend._lib.RSA_get0_crt_params( self._rsa_cdata, dmp1, dmq1, iqmp ) self._backend.openssl_assert(dmp1[0] != self._backend._ffi.NULL) self._backend.openssl_assert(dmq1[0] != self._backend._ffi.NULL) self._backend.openssl_assert(iqmp[0] != self._backend._ffi.NULL) return rsa.RSAPrivateNumbers( p=self._backend._bn_to_int(p[0]), q=self._backend._bn_to_int(q[0]), d=self._backend._bn_to_int(d[0]), dmp1=self._backend._bn_to_int(dmp1[0]), dmq1=self._backend._bn_to_int(dmq1[0]), iqmp=self._backend._bn_to_int(iqmp[0]), public_numbers=rsa.RSAPublicNumbers( e=self._backend._bn_to_int(e[0]), n=self._backend._bn_to_int(n[0]), ) ) def private_bytes(self, encoding, format, encryption_algorithm): return self._backend._private_key_bytes( encoding, format, encryption_algorithm, self._evp_pkey, self._rsa_cdata ) def sign(self, data, padding, algorithm): data, algorithm = _calculate_digest_and_algorithm( self._backend, data, algorithm ) return _rsa_sig_sign(self._backend, padding, algorithm, self, data) @utils.register_interface(RSAPublicKeyWithSerialization) class _RSAPublicKey(object): def __init__(self, backend, rsa_cdata, evp_pkey): self._backend = backend self._rsa_cdata = rsa_cdata self._evp_pkey = evp_pkey n = self._backend._ffi.new("BIGNUM **") self._backend._lib.RSA_get0_key( self._rsa_cdata, n, self._backend._ffi.NULL, self._backend._ffi.NULL ) self._backend.openssl_assert(n[0] != self._backend._ffi.NULL) self._key_size = self._backend._lib.BN_num_bits(n[0]) key_size = utils.read_only_property("_key_size") def verifier(self, signature, padding, algorithm): _warn_sign_verify_deprecated() utils._check_bytes("signature", signature) _check_not_prehashed(algorithm) return _RSAVerificationContext( self._backend, self, signature, padding, algorithm ) def encrypt(self, plaintext, padding): return _enc_dec_rsa(self._backend, self, plaintext, padding) def public_numbers(self): n = self._backend._ffi.new("BIGNUM **") e = self._backend._ffi.new("BIGNUM **") self._backend._lib.RSA_get0_key( self._rsa_cdata, n, e, self._backend._ffi.NULL ) self._backend.openssl_assert(n[0] != self._backend._ffi.NULL) self._backend.openssl_assert(e[0] != self._backend._ffi.NULL) return rsa.RSAPublicNumbers( e=self._backend._bn_to_int(e[0]), n=self._backend._bn_to_int(n[0]), ) def public_bytes(self, encoding, format): return self._backend._public_key_bytes( encoding, format, self, self._evp_pkey, self._rsa_cdata ) def verify(self, signature, data, padding, algorithm): data, algorithm = _calculate_digest_and_algorithm( self._backend, data, algorithm ) return _rsa_sig_verify( self._backend, padding, algorithm, self, signature, data )