mirror of
https://github.com/hakril/PythonForWindows
synced 2026-06-08 14:31:45 +00:00
hakril
120 lines
4.6 KiB
Python
120 lines
4.6 KiB
Python
from os import urandom
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from windows import winproxy
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from windows.crypto import DEFAULT_ENCODING
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from windows.generated_def import *
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__all__ = ["encrypt", "decrypt"]
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def encode_init_vector(data):
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blob = CRYPT_DATA_BLOB.from_string(data)
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size = DWORD()
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buf = None
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winproxy.CryptEncodeObjectEx(DEFAULT_ENCODING, X509_OCTET_STRING, ctypes.byref(blob), 0, None, buf, size)
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buf = (BYTE * size.value)()
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winproxy.CryptEncodeObjectEx(DEFAULT_ENCODING, X509_OCTET_STRING, ctypes.byref(blob), 0, None, buf, size)
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return buf[:]
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class GenerateInitVector(object):
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def __repr__(self):
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return "GenerateInitVector()"
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def generate_init_vector(self, algo):
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if algo in [szOID_OIWSEC_desCBC, szOID_RSA_DES_EDE3_CBC]:
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return urandom(8)
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if algo in [szOID_NIST_AES128_CBC, szOID_NIST_AES192_CBC, szOID_NIST_AES256_CBC]:
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return urandom(16)
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return None
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geninitvector = GenerateInitVector()
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def encrypt(cert_or_certlist, msg, algo=szOID_NIST_AES256_CBC, initvector=geninitvector):
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"""Encrypt ``msg`` one or many :class:`Certificate` using ``algo`` with the initial
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vector ``initvector``.
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If ``geninitvector`` is left as it is, it will generate a random one.
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Algorithms supported by ``GenerateInitVector`` are:
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* ``szOID_OIWSEC_desCBC``
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* ``szOID_RSA_DES_EDE3_CBC``
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* ``szOID_NIST_AES128_CBC``
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* ``szOID_NIST_AES192_CBC``
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* ``szOID_NIST_AES256_CBC``
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:param cert_or_certlist: One or many :class:`Certificate` used to encrypt the msg
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:type cert_or_certlist: :class:`Certificate` | [:class:`Certificate`]
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:return: :class:`bytearray`: The encrypted message
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"""
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alg_ident = CRYPT_ALGORITHM_IDENTIFIER()
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alg_ident.pszObjId = algo.encode("ascii")
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# We want to have automatique translation of Certificate -> PCERT_CONTEXT
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# In order to simple create the 'PCERT_CONTEXT[] certs'
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# For that we need a tuple of X * 1-item-tuple
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# as a (cert,) will be automaticly translatable to a PCERT_CONTEXT
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if isinstance(cert_or_certlist, CERT_CONTEXT):
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certlist = ((cert_or_certlist,),)
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else:
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certlist = tuple((c,) for c in cert_or_certlist)
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# Set (compute if needed) the IV
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if initvector is None:
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alg_ident.Parameters.cbData = 0
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elif initvector is geninitvector:
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initvector = initvector.generate_init_vector(algo)
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if initvector is None:
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raise ValueError("I don't know how to generate an <initvector> for <{0}> please provide one (or None)".format(algo))
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initvector_encoded = encode_init_vector(initvector)
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alg_ident.Parameters = CRYPT_DATA_BLOB.from_string(initvector_encoded)
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else:
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initvector_encoded = encode_init_vector(initvector)
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alg_ident.Parameters = CRYPT_DATA_BLOB.from_string(initvector_encoded)
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# Setup encryption parameters
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param = CRYPT_ENCRYPT_MESSAGE_PARA()
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param.cbSize = ctypes.sizeof(param)
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param.dwMsgEncodingType = DEFAULT_ENCODING
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param.hCryptProv = None
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param.ContentEncryptionAlgorithm = alg_ident
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param.pvEncryptionAuxInfo = None
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param.dwFlags = 0
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param.dwInnerContentType = 0
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certs = (PCERT_CONTEXT * len(certlist))(*certlist)
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#Ask the output buffer size
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size = DWORD()
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winproxy.CryptEncryptMessage(param, len(certs), certs, msg, len(msg), None, size)
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#Encrypt the msg
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buf = (BYTE * size.value)()
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winproxy.CryptEncryptMessage(param, len(certs), certs, msg, len(msg), buf, size)
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return bytearray(buf[:size.value])
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def decrypt(cert_store, encrypted):
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"""Try to decrypt the ``encrypted`` msg with any certificate in ``cert_store``.
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If there is no certificate able to decrypt the message ``WinproxyError(winerror=0x8009200c)`` is raised.
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:param cert_store:
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:type cert_store: :class:`CertificateStore`
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:return: :class:`str`: The decrypted message
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"""
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# Setup decryption parameters
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dparam = CRYPT_DECRYPT_MESSAGE_PARA()
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dparam.cbSize = ctypes.sizeof(dparam)
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dparam.dwMsgAndCertEncodingType = DEFAULT_ENCODING
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dparam.cCertStore = 1
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dparam.rghCertStore = (cert_store,)
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dparam.dwFlags = 0
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#Ask the output buffer size
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buf = (BYTE * len(encrypted)).from_buffer_copy(encrypted)
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dcryptsize = DWORD()
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winproxy.CryptDecryptMessage(dparam, buf, ctypes.sizeof(buf), None, dcryptsize, None)
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#Decrypt the msg
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dcryptbuff = (BYTE * (dcryptsize.value + 0x1000))()
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winproxy.CryptDecryptMessage(dparam, buf, ctypes.sizeof(buf), dcryptbuff, dcryptsize, None)
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return bytes(bytearray(dcryptbuff[:dcryptsize.value]))
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