304 lines
12 KiB
Python
304 lines
12 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 InvalidSignature
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from cryptography.hazmat.backends.openssl.utils import _truncate_digest
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from cryptography.hazmat.primitives import hashes, serialization
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from cryptography.hazmat.primitives.asymmetric import (
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AsymmetricSignatureContext, AsymmetricVerificationContext, dsa
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)
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def _truncate_digest_for_dsa(dsa_cdata, digest, backend):
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"""
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This function truncates digests that are longer than a given DS
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key's length so they can be signed. OpenSSL does this for us in
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1.0.0c+ and it isn't needed in 0.9.8, but that leaves us with three
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releases (1.0.0, 1.0.0a, and 1.0.0b) where this is a problem. This
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truncation is not required in 0.9.8 because DSA is limited to SHA-1.
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"""
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q = backend._ffi.new("BIGNUM **")
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backend._lib.DSA_get0_pqg(
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dsa_cdata, backend._ffi.NULL, q, backend._ffi.NULL
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)
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backend.openssl_assert(q[0] != backend._ffi.NULL)
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order_bits = backend._lib.BN_num_bits(q[0])
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return _truncate_digest(digest, order_bits)
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@utils.register_interface(AsymmetricVerificationContext)
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class _DSAVerificationContext(object):
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def __init__(self, backend, public_key, signature, 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._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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data_to_verify = self._hash_ctx.finalize()
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data_to_verify = _truncate_digest_for_dsa(
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self._public_key._dsa_cdata, data_to_verify, self._backend
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)
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# The first parameter passed to DSA_verify is unused by OpenSSL but
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# must be an integer.
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res = self._backend._lib.DSA_verify(
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0, data_to_verify, len(data_to_verify), self._signature,
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len(self._signature), self._public_key._dsa_cdata)
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if res != 1:
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self._backend._consume_errors()
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raise InvalidSignature
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@utils.register_interface(AsymmetricSignatureContext)
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class _DSASignatureContext(object):
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def __init__(self, backend, private_key, algorithm):
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self._backend = backend
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self._private_key = private_key
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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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data_to_sign = self._hash_ctx.finalize()
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data_to_sign = _truncate_digest_for_dsa(
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self._private_key._dsa_cdata, data_to_sign, self._backend
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)
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sig_buf_len = self._backend._lib.DSA_size(self._private_key._dsa_cdata)
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sig_buf = self._backend._ffi.new("unsigned char[]", sig_buf_len)
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buflen = self._backend._ffi.new("unsigned int *")
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# The first parameter passed to DSA_sign is unused by OpenSSL but
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# must be an integer.
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res = self._backend._lib.DSA_sign(
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0, data_to_sign, len(data_to_sign), sig_buf,
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buflen, self._private_key._dsa_cdata)
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self._backend.openssl_assert(res == 1)
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self._backend.openssl_assert(buflen[0])
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return self._backend._ffi.buffer(sig_buf)[:buflen[0]]
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@utils.register_interface(dsa.DSAParametersWithNumbers)
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class _DSAParameters(object):
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def __init__(self, backend, dsa_cdata):
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self._backend = backend
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self._dsa_cdata = dsa_cdata
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def parameter_numbers(self):
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p = self._backend._ffi.new("BIGNUM **")
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q = self._backend._ffi.new("BIGNUM **")
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g = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.DSA_get0_pqg(self._dsa_cdata, p, q, g)
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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.openssl_assert(g[0] != self._backend._ffi.NULL)
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return dsa.DSAParameterNumbers(
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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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g=self._backend._bn_to_int(g[0])
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)
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def generate_private_key(self):
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return self._backend.generate_dsa_private_key(self)
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@utils.register_interface(dsa.DSAPrivateKeyWithSerialization)
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class _DSAPrivateKey(object):
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def __init__(self, backend, dsa_cdata, evp_pkey):
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self._backend = backend
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self._dsa_cdata = dsa_cdata
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self._evp_pkey = evp_pkey
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p = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.DSA_get0_pqg(
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dsa_cdata, p, self._backend._ffi.NULL, self._backend._ffi.NULL
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)
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self._backend.openssl_assert(p[0] != backend._ffi.NULL)
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self._key_size = self._backend._lib.BN_num_bits(p[0])
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key_size = utils.read_only_property("_key_size")
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def signer(self, signature_algorithm):
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return _DSASignatureContext(self._backend, self, signature_algorithm)
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def private_numbers(self):
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p = self._backend._ffi.new("BIGNUM **")
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q = self._backend._ffi.new("BIGNUM **")
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g = self._backend._ffi.new("BIGNUM **")
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pub_key = self._backend._ffi.new("BIGNUM **")
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priv_key = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.DSA_get0_pqg(self._dsa_cdata, p, q, g)
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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.openssl_assert(g[0] != self._backend._ffi.NULL)
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self._backend._lib.DSA_get0_key(self._dsa_cdata, pub_key, priv_key)
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self._backend.openssl_assert(pub_key[0] != self._backend._ffi.NULL)
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self._backend.openssl_assert(priv_key[0] != self._backend._ffi.NULL)
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return dsa.DSAPrivateNumbers(
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public_numbers=dsa.DSAPublicNumbers(
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parameter_numbers=dsa.DSAParameterNumbers(
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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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g=self._backend._bn_to_int(g[0])
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),
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y=self._backend._bn_to_int(pub_key[0])
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),
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x=self._backend._bn_to_int(priv_key[0])
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)
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def public_key(self):
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dsa_cdata = self._backend._lib.DSA_new()
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self._backend.openssl_assert(dsa_cdata != self._backend._ffi.NULL)
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dsa_cdata = self._backend._ffi.gc(
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dsa_cdata, self._backend._lib.DSA_free
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)
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p = self._backend._ffi.new("BIGNUM **")
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q = self._backend._ffi.new("BIGNUM **")
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g = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.DSA_get0_pqg(self._dsa_cdata, p, q, g)
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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.openssl_assert(g[0] != self._backend._ffi.NULL)
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p_dup = self._backend._lib.BN_dup(p[0])
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q_dup = self._backend._lib.BN_dup(q[0])
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g_dup = self._backend._lib.BN_dup(g[0])
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res = self._backend._lib.DSA_set0_pqg(dsa_cdata, p_dup, q_dup, g_dup)
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self._backend.openssl_assert(res == 1)
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pub_key = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.DSA_get0_key(
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self._dsa_cdata, pub_key, self._backend._ffi.NULL
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)
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self._backend.openssl_assert(pub_key[0] != self._backend._ffi.NULL)
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pub_key_dup = self._backend._lib.BN_dup(pub_key[0])
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res = self._backend._lib.DSA_set0_key(
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dsa_cdata, pub_key_dup, self._backend._ffi.NULL
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)
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self._backend.openssl_assert(res == 1)
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evp_pkey = self._backend._dsa_cdata_to_evp_pkey(dsa_cdata)
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return _DSAPublicKey(self._backend, dsa_cdata, evp_pkey)
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def parameters(self):
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dsa_cdata = self._backend._lib.DSA_new()
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self._backend.openssl_assert(dsa_cdata != self._backend._ffi.NULL)
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dsa_cdata = self._backend._ffi.gc(
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dsa_cdata, self._backend._lib.DSA_free
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)
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p = self._backend._ffi.new("BIGNUM **")
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q = self._backend._ffi.new("BIGNUM **")
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g = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.DSA_get0_pqg(self._dsa_cdata, p, q, g)
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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.openssl_assert(g[0] != self._backend._ffi.NULL)
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p_dup = self._backend._lib.BN_dup(p[0])
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q_dup = self._backend._lib.BN_dup(q[0])
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g_dup = self._backend._lib.BN_dup(g[0])
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res = self._backend._lib.DSA_set0_pqg(dsa_cdata, p_dup, q_dup, g_dup)
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self._backend.openssl_assert(res == 1)
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return _DSAParameters(self._backend, dsa_cdata)
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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._evp_pkey,
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self._dsa_cdata
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)
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@utils.register_interface(dsa.DSAPublicKeyWithSerialization)
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class _DSAPublicKey(object):
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def __init__(self, backend, dsa_cdata, evp_pkey):
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self._backend = backend
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self._dsa_cdata = dsa_cdata
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self._evp_pkey = evp_pkey
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p = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.DSA_get0_pqg(
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dsa_cdata, p, self._backend._ffi.NULL, self._backend._ffi.NULL
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)
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self._backend.openssl_assert(p[0] != backend._ffi.NULL)
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self._key_size = self._backend._lib.BN_num_bits(p[0])
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key_size = utils.read_only_property("_key_size")
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def verifier(self, signature, signature_algorithm):
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if not isinstance(signature, bytes):
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raise TypeError("signature must be bytes.")
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return _DSAVerificationContext(
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self._backend, self, signature, signature_algorithm
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)
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def public_numbers(self):
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p = self._backend._ffi.new("BIGNUM **")
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q = self._backend._ffi.new("BIGNUM **")
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g = self._backend._ffi.new("BIGNUM **")
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pub_key = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.DSA_get0_pqg(self._dsa_cdata, p, q, g)
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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.openssl_assert(g[0] != self._backend._ffi.NULL)
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self._backend._lib.DSA_get0_key(
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self._dsa_cdata, pub_key, self._backend._ffi.NULL
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)
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self._backend.openssl_assert(pub_key[0] != self._backend._ffi.NULL)
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return dsa.DSAPublicNumbers(
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parameter_numbers=dsa.DSAParameterNumbers(
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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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g=self._backend._bn_to_int(g[0])
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),
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y=self._backend._bn_to_int(pub_key[0])
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)
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def parameters(self):
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dsa_cdata = self._backend._lib.DSA_new()
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self._backend.openssl_assert(dsa_cdata != self._backend._ffi.NULL)
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dsa_cdata = self._backend._ffi.gc(
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dsa_cdata, self._backend._lib.DSA_free
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)
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p = self._backend._ffi.new("BIGNUM **")
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q = self._backend._ffi.new("BIGNUM **")
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g = self._backend._ffi.new("BIGNUM **")
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self._backend._lib.DSA_get0_pqg(self._dsa_cdata, p, q, g)
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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.openssl_assert(g[0] != self._backend._ffi.NULL)
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p_dup = self._backend._lib.BN_dup(p[0])
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q_dup = self._backend._lib.BN_dup(q[0])
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g_dup = self._backend._lib.BN_dup(g[0])
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res = self._backend._lib.DSA_set0_pqg(dsa_cdata, p_dup, q_dup, g_dup)
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self._backend.openssl_assert(res == 1)
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return _DSAParameters(self._backend, dsa_cdata)
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def public_bytes(self, encoding, format):
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if format is serialization.PublicFormat.PKCS1:
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raise ValueError(
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"DSA public keys do not support PKCS1 serialization"
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)
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return self._backend._public_key_bytes(
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encoding,
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format,
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self,
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self._evp_pkey,
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None
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)
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