mirror of
https://github.com/PiBrewing/craftbeerpi4.git
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516 lines
19 KiB
Python
516 lines
19 KiB
Python
# This file is dual licensed under the terms of the Apache License, Version
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# 2.0, and the BSD License. See the LICENSE file in the root of this repository
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# for complete details.
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from __future__ import absolute_import, division, print_function
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from cryptography import utils
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from cryptography.exceptions import (
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InvalidSignature,
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UnsupportedAlgorithm,
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_Reasons,
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)
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from cryptography.hazmat.backends.openssl.utils import (
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_calculate_digest_and_algorithm,
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_check_not_prehashed,
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_warn_sign_verify_deprecated,
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)
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from cryptography.hazmat.primitives import hashes
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from cryptography.hazmat.primitives.asymmetric import (
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AsymmetricSignatureContext,
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AsymmetricVerificationContext,
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rsa,
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)
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from cryptography.hazmat.primitives.asymmetric.padding import (
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AsymmetricPadding,
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MGF1,
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OAEP,
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PKCS1v15,
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PSS,
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calculate_max_pss_salt_length,
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)
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from cryptography.hazmat.primitives.asymmetric.rsa import (
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RSAPrivateKeyWithSerialization,
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RSAPublicKeyWithSerialization,
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)
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def _get_rsa_pss_salt_length(pss, key, hash_algorithm):
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salt = pss._salt_length
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if salt is MGF1.MAX_LENGTH or salt is PSS.MAX_LENGTH:
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return calculate_max_pss_salt_length(key, hash_algorithm)
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else:
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return salt
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def _enc_dec_rsa(backend, key, data, padding):
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if not isinstance(padding, AsymmetricPadding):
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raise TypeError("Padding must be an instance of AsymmetricPadding.")
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if isinstance(padding, PKCS1v15):
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padding_enum = backend._lib.RSA_PKCS1_PADDING
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elif isinstance(padding, OAEP):
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padding_enum = backend._lib.RSA_PKCS1_OAEP_PADDING
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if not isinstance(padding._mgf, MGF1):
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raise UnsupportedAlgorithm(
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"Only MGF1 is supported by this backend.",
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_Reasons.UNSUPPORTED_MGF,
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)
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if not backend.rsa_padding_supported(padding):
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raise UnsupportedAlgorithm(
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"This combination of padding and hash algorithm is not "
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"supported by this backend.",
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_Reasons.UNSUPPORTED_PADDING,
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)
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else:
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raise UnsupportedAlgorithm(
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"{} is not supported by this backend.".format(padding.name),
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_Reasons.UNSUPPORTED_PADDING,
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)
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return _enc_dec_rsa_pkey_ctx(backend, key, data, padding_enum, padding)
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def _enc_dec_rsa_pkey_ctx(backend, key, data, padding_enum, padding):
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if isinstance(key, _RSAPublicKey):
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init = backend._lib.EVP_PKEY_encrypt_init
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crypt = backend._lib.EVP_PKEY_encrypt
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else:
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init = backend._lib.EVP_PKEY_decrypt_init
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crypt = backend._lib.EVP_PKEY_decrypt
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pkey_ctx = backend._lib.EVP_PKEY_CTX_new(key._evp_pkey, backend._ffi.NULL)
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backend.openssl_assert(pkey_ctx != backend._ffi.NULL)
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pkey_ctx = backend._ffi.gc(pkey_ctx, backend._lib.EVP_PKEY_CTX_free)
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res = init(pkey_ctx)
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backend.openssl_assert(res == 1)
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res = backend._lib.EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, padding_enum)
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backend.openssl_assert(res > 0)
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buf_size = backend._lib.EVP_PKEY_size(key._evp_pkey)
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backend.openssl_assert(buf_size > 0)
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if isinstance(padding, OAEP) and backend._lib.Cryptography_HAS_RSA_OAEP_MD:
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mgf1_md = backend._evp_md_non_null_from_algorithm(
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padding._mgf._algorithm
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)
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res = backend._lib.EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, mgf1_md)
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backend.openssl_assert(res > 0)
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oaep_md = backend._evp_md_non_null_from_algorithm(padding._algorithm)
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res = backend._lib.EVP_PKEY_CTX_set_rsa_oaep_md(pkey_ctx, oaep_md)
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backend.openssl_assert(res > 0)
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if (
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isinstance(padding, OAEP)
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and padding._label is not None
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and len(padding._label) > 0
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):
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# set0_rsa_oaep_label takes ownership of the char * so we need to
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# copy it into some new memory
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labelptr = backend._lib.OPENSSL_malloc(len(padding._label))
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backend.openssl_assert(labelptr != backend._ffi.NULL)
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backend._ffi.memmove(labelptr, padding._label, len(padding._label))
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res = backend._lib.EVP_PKEY_CTX_set0_rsa_oaep_label(
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pkey_ctx, labelptr, len(padding._label)
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)
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backend.openssl_assert(res == 1)
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outlen = backend._ffi.new("size_t *", buf_size)
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buf = backend._ffi.new("unsigned char[]", buf_size)
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# Everything from this line onwards is written with the goal of being as
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# constant-time as is practical given the constraints of Python and our
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# API. See Bleichenbacher's '98 attack on RSA, and its many many variants.
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# As such, you should not attempt to change this (particularly to "clean it
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# up") without understanding why it was written this way (see
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# Chesterton's Fence), and without measuring to verify you have not
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# introduced observable time differences.
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res = crypt(pkey_ctx, buf, outlen, data, len(data))
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resbuf = backend._ffi.buffer(buf)[: outlen[0]]
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backend._lib.ERR_clear_error()
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if res <= 0:
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raise ValueError("Encryption/decryption failed.")
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return resbuf
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def _rsa_sig_determine_padding(backend, key, padding, algorithm):
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if not isinstance(padding, AsymmetricPadding):
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raise TypeError("Expected provider of AsymmetricPadding.")
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pkey_size = backend._lib.EVP_PKEY_size(key._evp_pkey)
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backend.openssl_assert(pkey_size > 0)
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if isinstance(padding, PKCS1v15):
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# Hash algorithm is ignored for PKCS1v15-padding, may be None.
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padding_enum = backend._lib.RSA_PKCS1_PADDING
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elif isinstance(padding, PSS):
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if not isinstance(padding._mgf, MGF1):
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raise UnsupportedAlgorithm(
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"Only MGF1 is supported by this backend.",
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_Reasons.UNSUPPORTED_MGF,
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)
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# PSS padding requires a hash algorithm
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if not isinstance(algorithm, hashes.HashAlgorithm):
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raise TypeError("Expected instance of hashes.HashAlgorithm.")
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# Size of key in bytes - 2 is the maximum
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# PSS signature length (salt length is checked later)
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if pkey_size - algorithm.digest_size - 2 < 0:
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raise ValueError(
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"Digest too large for key size. Use a larger "
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"key or different digest."
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)
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padding_enum = backend._lib.RSA_PKCS1_PSS_PADDING
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else:
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raise UnsupportedAlgorithm(
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"{} is not supported by this backend.".format(padding.name),
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_Reasons.UNSUPPORTED_PADDING,
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)
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return padding_enum
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# Hash algorithm can be absent (None) to initialize the context without setting
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# any message digest algorithm. This is currently only valid for the PKCS1v15
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# padding type, where it means that the signature data is encoded/decoded
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# as provided, without being wrapped in a DigestInfo structure.
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def _rsa_sig_setup(backend, padding, algorithm, key, init_func):
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padding_enum = _rsa_sig_determine_padding(backend, key, padding, algorithm)
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pkey_ctx = backend._lib.EVP_PKEY_CTX_new(key._evp_pkey, backend._ffi.NULL)
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backend.openssl_assert(pkey_ctx != backend._ffi.NULL)
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pkey_ctx = backend._ffi.gc(pkey_ctx, backend._lib.EVP_PKEY_CTX_free)
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res = init_func(pkey_ctx)
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backend.openssl_assert(res == 1)
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if algorithm is not None:
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evp_md = backend._evp_md_non_null_from_algorithm(algorithm)
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res = backend._lib.EVP_PKEY_CTX_set_signature_md(pkey_ctx, evp_md)
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if res == 0:
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backend._consume_errors()
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raise UnsupportedAlgorithm(
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"{} is not supported by this backend for RSA signing.".format(
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algorithm.name
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),
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_Reasons.UNSUPPORTED_HASH,
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)
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res = backend._lib.EVP_PKEY_CTX_set_rsa_padding(pkey_ctx, padding_enum)
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if res <= 0:
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backend._consume_errors()
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raise UnsupportedAlgorithm(
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"{} is not supported for the RSA signature operation.".format(
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padding.name
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),
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_Reasons.UNSUPPORTED_PADDING,
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)
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if isinstance(padding, PSS):
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res = backend._lib.EVP_PKEY_CTX_set_rsa_pss_saltlen(
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pkey_ctx, _get_rsa_pss_salt_length(padding, key, algorithm)
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)
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backend.openssl_assert(res > 0)
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mgf1_md = backend._evp_md_non_null_from_algorithm(
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padding._mgf._algorithm
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)
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res = backend._lib.EVP_PKEY_CTX_set_rsa_mgf1_md(pkey_ctx, mgf1_md)
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backend.openssl_assert(res > 0)
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return pkey_ctx
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def _rsa_sig_sign(backend, padding, algorithm, private_key, data):
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pkey_ctx = _rsa_sig_setup(
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backend,
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padding,
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algorithm,
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private_key,
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backend._lib.EVP_PKEY_sign_init,
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)
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buflen = backend._ffi.new("size_t *")
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res = backend._lib.EVP_PKEY_sign(
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pkey_ctx, backend._ffi.NULL, buflen, data, len(data)
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)
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backend.openssl_assert(res == 1)
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buf = backend._ffi.new("unsigned char[]", buflen[0])
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res = backend._lib.EVP_PKEY_sign(pkey_ctx, buf, buflen, data, len(data))
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if res != 1:
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errors = backend._consume_errors_with_text()
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raise ValueError(
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"Digest or salt length too long for key size. Use a larger key "
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"or shorter salt length if you are specifying a PSS salt",
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errors,
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)
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return backend._ffi.buffer(buf)[:]
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def _rsa_sig_verify(backend, padding, algorithm, public_key, signature, data):
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pkey_ctx = _rsa_sig_setup(
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backend,
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padding,
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algorithm,
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public_key,
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backend._lib.EVP_PKEY_verify_init,
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)
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res = backend._lib.EVP_PKEY_verify(
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pkey_ctx, signature, len(signature), data, len(data)
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)
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# The previous call can return negative numbers in the event of an
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# error. This is not a signature failure but we need to fail if it
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# occurs.
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backend.openssl_assert(res >= 0)
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if res == 0:
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backend._consume_errors()
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raise InvalidSignature
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def _rsa_sig_recover(backend, padding, algorithm, public_key, signature):
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pkey_ctx = _rsa_sig_setup(
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backend,
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padding,
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algorithm,
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public_key,
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backend._lib.EVP_PKEY_verify_recover_init,
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)
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# Attempt to keep the rest of the code in this function as constant/time
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# as possible. See the comment in _enc_dec_rsa_pkey_ctx. Note that the
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# outlen parameter is used even though its value may be undefined in the
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# error case. Due to the tolerant nature of Python slicing this does not
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# trigger any exceptions.
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maxlen = backend._lib.EVP_PKEY_size(public_key._evp_pkey)
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backend.openssl_assert(maxlen > 0)
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buf = backend._ffi.new("unsigned char[]", maxlen)
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buflen = backend._ffi.new("size_t *", maxlen)
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res = backend._lib.EVP_PKEY_verify_recover(
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pkey_ctx, buf, buflen, signature, len(signature)
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)
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resbuf = backend._ffi.buffer(buf)[: buflen[0]]
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backend._lib.ERR_clear_error()
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# Assume that all parameter errors are handled during the setup phase and
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# any error here is due to invalid signature.
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if res != 1:
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raise InvalidSignature
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return resbuf
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@utils.register_interface(AsymmetricSignatureContext)
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class _RSASignatureContext(object):
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def __init__(self, backend, private_key, padding, algorithm):
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self._backend = backend
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self._private_key = private_key
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# We now call _rsa_sig_determine_padding in _rsa_sig_setup. However
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# we need to make a pointless call to it here so we maintain the
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# API of erroring on init with this context if the values are invalid.
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_rsa_sig_determine_padding(backend, private_key, padding, algorithm)
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self._padding = padding
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self._algorithm = algorithm
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self._hash_ctx = hashes.Hash(self._algorithm, self._backend)
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def update(self, data):
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self._hash_ctx.update(data)
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def finalize(self):
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return _rsa_sig_sign(
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self._backend,
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self._padding,
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self._algorithm,
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self._private_key,
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self._hash_ctx.finalize(),
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)
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@utils.register_interface(AsymmetricVerificationContext)
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class _RSAVerificationContext(object):
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def __init__(self, backend, public_key, signature, padding, algorithm):
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self._backend = backend
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self._public_key = public_key
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self._signature = signature
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self._padding = padding
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# We now call _rsa_sig_determine_padding in _rsa_sig_setup. However
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# we need to make a pointless call to it here so we maintain the
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# API of erroring on init with this context if the values are invalid.
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_rsa_sig_determine_padding(backend, public_key, padding, algorithm)
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padding = padding
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self._algorithm = algorithm
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self._hash_ctx = hashes.Hash(self._algorithm, self._backend)
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def update(self, data):
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self._hash_ctx.update(data)
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def verify(self):
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return _rsa_sig_verify(
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self._backend,
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self._padding,
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self._algorithm,
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self._public_key,
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self._signature,
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self._hash_ctx.finalize(),
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)
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@utils.register_interface(RSAPrivateKeyWithSerialization)
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class _RSAPrivateKey(object):
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def __init__(self, backend, rsa_cdata, evp_pkey):
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res = backend._lib.RSA_check_key(rsa_cdata)
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if res != 1:
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errors = backend._consume_errors_with_text()
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raise ValueError("Invalid private key", errors)
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# Blinding is on by default in many versions of OpenSSL, but let's
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# just be conservative here.
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res = backend._lib.RSA_blinding_on(rsa_cdata, backend._ffi.NULL)
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backend.openssl_assert(res == 1)
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self._backend = backend
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self._rsa_cdata = rsa_cdata
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self._evp_pkey = evp_pkey
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n = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.RSA_get0_key(
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self._rsa_cdata,
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n,
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self._backend._ffi.NULL,
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self._backend._ffi.NULL,
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)
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self._backend.openssl_assert(n[0] != self._backend._ffi.NULL)
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self._key_size = self._backend._lib.BN_num_bits(n[0])
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key_size = utils.read_only_property("_key_size")
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def signer(self, padding, algorithm):
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_warn_sign_verify_deprecated()
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_check_not_prehashed(algorithm)
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return _RSASignatureContext(self._backend, self, padding, algorithm)
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def decrypt(self, ciphertext, padding):
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key_size_bytes = (self.key_size + 7) // 8
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if key_size_bytes != len(ciphertext):
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raise ValueError("Ciphertext length must be equal to key size.")
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return _enc_dec_rsa(self._backend, self, ciphertext, padding)
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def public_key(self):
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ctx = self._backend._lib.RSAPublicKey_dup(self._rsa_cdata)
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self._backend.openssl_assert(ctx != self._backend._ffi.NULL)
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ctx = self._backend._ffi.gc(ctx, self._backend._lib.RSA_free)
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evp_pkey = self._backend._rsa_cdata_to_evp_pkey(ctx)
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return _RSAPublicKey(self._backend, ctx, evp_pkey)
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def private_numbers(self):
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n = self._backend._ffi.new("BIGNUM **")
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e = self._backend._ffi.new("BIGNUM **")
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d = self._backend._ffi.new("BIGNUM **")
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p = self._backend._ffi.new("BIGNUM **")
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q = self._backend._ffi.new("BIGNUM **")
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dmp1 = self._backend._ffi.new("BIGNUM **")
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dmq1 = self._backend._ffi.new("BIGNUM **")
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iqmp = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.RSA_get0_key(self._rsa_cdata, n, e, d)
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self._backend.openssl_assert(n[0] != self._backend._ffi.NULL)
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self._backend.openssl_assert(e[0] != self._backend._ffi.NULL)
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self._backend.openssl_assert(d[0] != self._backend._ffi.NULL)
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self._backend._lib.RSA_get0_factors(self._rsa_cdata, p, q)
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self._backend.openssl_assert(p[0] != self._backend._ffi.NULL)
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self._backend.openssl_assert(q[0] != self._backend._ffi.NULL)
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self._backend._lib.RSA_get0_crt_params(
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self._rsa_cdata, dmp1, dmq1, iqmp
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)
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self._backend.openssl_assert(dmp1[0] != self._backend._ffi.NULL)
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self._backend.openssl_assert(dmq1[0] != self._backend._ffi.NULL)
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self._backend.openssl_assert(iqmp[0] != self._backend._ffi.NULL)
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return rsa.RSAPrivateNumbers(
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p=self._backend._bn_to_int(p[0]),
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q=self._backend._bn_to_int(q[0]),
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d=self._backend._bn_to_int(d[0]),
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dmp1=self._backend._bn_to_int(dmp1[0]),
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dmq1=self._backend._bn_to_int(dmq1[0]),
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iqmp=self._backend._bn_to_int(iqmp[0]),
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public_numbers=rsa.RSAPublicNumbers(
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e=self._backend._bn_to_int(e[0]),
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n=self._backend._bn_to_int(n[0]),
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),
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)
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def private_bytes(self, encoding, format, encryption_algorithm):
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return self._backend._private_key_bytes(
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encoding,
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format,
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encryption_algorithm,
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self,
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self._evp_pkey,
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self._rsa_cdata,
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)
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def sign(self, data, padding, algorithm):
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data, algorithm = _calculate_digest_and_algorithm(
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self._backend, data, algorithm
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)
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return _rsa_sig_sign(self._backend, padding, algorithm, self, data)
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@utils.register_interface(RSAPublicKeyWithSerialization)
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class _RSAPublicKey(object):
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def __init__(self, backend, rsa_cdata, evp_pkey):
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self._backend = backend
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self._rsa_cdata = rsa_cdata
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self._evp_pkey = evp_pkey
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n = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.RSA_get0_key(
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self._rsa_cdata,
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n,
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self._backend._ffi.NULL,
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self._backend._ffi.NULL,
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)
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self._backend.openssl_assert(n[0] != self._backend._ffi.NULL)
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self._key_size = self._backend._lib.BN_num_bits(n[0])
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key_size = utils.read_only_property("_key_size")
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def verifier(self, signature, padding, algorithm):
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_warn_sign_verify_deprecated()
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utils._check_bytes("signature", signature)
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_check_not_prehashed(algorithm)
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return _RSAVerificationContext(
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self._backend, self, signature, padding, algorithm
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)
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def encrypt(self, plaintext, padding):
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return _enc_dec_rsa(self._backend, self, plaintext, padding)
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def public_numbers(self):
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n = self._backend._ffi.new("BIGNUM **")
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e = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.RSA_get0_key(
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self._rsa_cdata, n, e, self._backend._ffi.NULL
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)
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self._backend.openssl_assert(n[0] != self._backend._ffi.NULL)
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self._backend.openssl_assert(e[0] != self._backend._ffi.NULL)
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return rsa.RSAPublicNumbers(
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e=self._backend._bn_to_int(e[0]),
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n=self._backend._bn_to_int(n[0]),
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)
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def public_bytes(self, encoding, format):
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return self._backend._public_key_bytes(
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encoding, format, self, self._evp_pkey, self._rsa_cdata
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)
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def verify(self, signature, data, padding, algorithm):
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data, algorithm = _calculate_digest_and_algorithm(
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self._backend, data, algorithm
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)
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return _rsa_sig_verify(
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self._backend, padding, algorithm, self, signature, data
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)
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def recover_data_from_signature(self, signature, padding, algorithm):
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_check_not_prehashed(algorithm)
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return _rsa_sig_recover(
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self._backend, padding, algorithm, self, signature
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)
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