nzbToMedia/libs/win/jaraco/windows/dpapi.py
2022-11-29 00:44:47 -05:00

144 lines
4.1 KiB
Python

"""
Python routines to interface with the Microsoft
Data Protection API (DPAPI).
>>> orig_data = b'Ipsum Lorem...'
>>> ciphertext = CryptProtectData(orig_data)
>>> descr, data = CryptUnprotectData(ciphertext)
>>> data == orig_data
True
"""
import ctypes
from ctypes import wintypes
from jaraco.windows.error import handle_nonzero_success
# for type declarations
__import__('jaraco.windows.api.memory')
class DATA_BLOB(ctypes.Structure):
r"""
A data blob structure for use with MS DPAPI functions.
Initialize with string of characters
>>> input = b'abc123\x00456'
>>> blob = DATA_BLOB(input)
>>> len(blob)
10
>>> blob.get_data() == input
True
"""
_fields_ = [('data_size', wintypes.DWORD), ('data', ctypes.c_void_p)]
def __init__(self, data=None):
super(DATA_BLOB, self).__init__()
self.set_data(data)
def set_data(self, data):
"Use this method to set the data for this blob"
if data is None:
self.data_size = 0
self.data = None
return
self.data_size = len(data)
# create a string buffer so that null bytes aren't interpreted
# as the end of the string
self.data = ctypes.cast(ctypes.create_string_buffer(data), ctypes.c_void_p)
def get_data(self):
"Get the data for this blob"
array = ctypes.POINTER(ctypes.c_char * len(self))
return ctypes.cast(self.data, array).contents.raw
def __len__(self):
return self.data_size
def __str__(self):
return self.get_data()
def free(self):
"""
"data out" blobs have locally-allocated memory.
Call this method to free the memory allocated by CryptProtectData
and CryptUnprotectData.
"""
ctypes.windll.kernel32.LocalFree(self.data)
p_DATA_BLOB = ctypes.POINTER(DATA_BLOB)
_CryptProtectData = ctypes.windll.crypt32.CryptProtectData
_CryptProtectData.argtypes = [
p_DATA_BLOB, # data in
wintypes.LPCWSTR, # data description
p_DATA_BLOB, # optional entropy
ctypes.c_void_p, # reserved
ctypes.c_void_p, # POINTER(CRYPTPROTECT_PROMPTSTRUCT), # prompt struct
wintypes.DWORD, # flags
p_DATA_BLOB, # data out
]
_CryptProtectData.restype = wintypes.BOOL
_CryptUnprotectData = ctypes.windll.crypt32.CryptUnprotectData
_CryptUnprotectData.argtypes = [
p_DATA_BLOB, # data in
ctypes.POINTER(wintypes.LPWSTR), # data description
p_DATA_BLOB, # optional entropy
ctypes.c_void_p, # reserved
ctypes.c_void_p, # POINTER(CRYPTPROTECT_PROMPTSTRUCT), # prompt struct
wintypes.DWORD, # flags
p_DATA_BLOB, # data out
]
_CryptUnprotectData.restype = wintypes.BOOL
CRYPTPROTECT_UI_FORBIDDEN = 0x01
def CryptProtectData(
data, description=None, optional_entropy=None, prompt_struct=None, flags=0
):
"""
Encrypt data
"""
data_in = DATA_BLOB(data)
entropy = DATA_BLOB(optional_entropy) if optional_entropy else None
data_out = DATA_BLOB()
res = _CryptProtectData(
data_in, description, entropy, None, prompt_struct, flags, data_out # reserved
)
handle_nonzero_success(res)
res = data_out.get_data()
data_out.free()
return res
def CryptUnprotectData(data, optional_entropy=None, prompt_struct=None, flags=0):
"""
Returns a tuple of (description, data) where description is the
the description that was passed to the CryptProtectData call and
data is the decrypted result.
"""
data_in = DATA_BLOB(data)
entropy = DATA_BLOB(optional_entropy) if optional_entropy else None
data_out = DATA_BLOB()
ptr_description = wintypes.LPWSTR()
res = _CryptUnprotectData(
data_in,
ctypes.byref(ptr_description),
entropy,
None, # reserved
prompt_struct,
flags | CRYPTPROTECT_UI_FORBIDDEN,
data_out,
)
handle_nonzero_success(res)
description = ptr_description.value
if ptr_description.value is not None:
ctypes.windll.kernel32.LocalFree(ptr_description)
res = data_out.get_data()
data_out.free()
return description, res