| # 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 math |
| |
| 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( |
| "{0} 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_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( |
| "{0} 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( |
| "{0} 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 = int(math.ceil(self.key_size / 8.0)) |
| 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 |
| ) |