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Windows 10 Prefetch (native) Decompress
#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# Copyright 2015, Francesco "dfirfpi" Picasso <francesco.picasso@gmail.com>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
"""Python Windows-only utility to decompress MAM compressed files."""
import binascii
import ctypes
import struct
import sys
def tohex(val, nbits):
"""Utility to convert (signed) integer to hex."""
return hex((val + (1 << nbits)) % (1 << nbits))
def main():
"""Utility core."""
if len(sys.argv) != 3:
sys.exit('Missing params [win10compressed.pf] [win10decompressed.pf]')
NULL = ctypes.POINTER(ctypes.c_uint)()
SIZE_T = ctypes.c_uint
DWORD = ctypes.c_uint32
USHORT = ctypes.c_uint16
UCHAR = ctypes.c_ubyte
ULONG = ctypes.c_uint32
# You must have at least Windows 8, or it should fail.
try:
RtlDecompressBufferEx = ctypes.windll.ntdll.RtlDecompressBufferEx
except AttributeError:
sys.exit('You must have Windows with version >=8.')
RtlGetCompressionWorkSpaceSize = \
ctypes.windll.ntdll.RtlGetCompressionWorkSpaceSize
with open(sys.argv[1], 'rb') as fin:
header = fin.read(8)
compressed = fin.read()
signature, decompressed_size = struct.unpack('<LL', header)
calgo = (signature & 0x0F000000) >> 24
crcck = (signature & 0xF0000000) >> 28
magic = signature & 0x00FFFFFF
if magic != 0x004d414d :
sys.exit('Wrong signature... wrong file?')
if crcck:
# I could have used RtlComputeCrc32.
file_crc = struct.unpack('<L', compressed[:4])[0]
crc = binascii.crc32(header)
crc = binascii.crc32(struct.pack('<L',0), crc)
compressed = compressed[4:]
crc = binascii.crc32(compressed, crc)
if crc != file_crc:
sys.exit('Wrong file CRC {0:x} - {1:x}!'.format(crc, file_crc))
compressed_size = len(compressed)
ntCompressBufferWorkSpaceSize = ULONG()
ntCompressFragmentWorkSpaceSize = ULONG()
ntstatus = RtlGetCompressionWorkSpaceSize(USHORT(calgo),
ctypes.byref(ntCompressBufferWorkSpaceSize),
ctypes.byref(ntCompressFragmentWorkSpaceSize))
if ntstatus:
sys.exit('Cannot get workspace size, err: {}'.format(
tohex(ntstatus, 32)))
ntCompressed = (UCHAR * compressed_size).from_buffer_copy(compressed)
ntDecompressed = (UCHAR * decompressed_size)()
ntFinalUncompressedSize = ULONG()
ntWorkspace = (UCHAR * ntCompressFragmentWorkSpaceSize.value)()
ntstatus = RtlDecompressBufferEx(
USHORT(calgo),
ctypes.byref(ntDecompressed),
ULONG(decompressed_size),
ctypes.byref(ntCompressed),
ULONG(compressed_size),
ctypes.byref(ntFinalUncompressedSize),
ctypes.byref(ntWorkspace))
if ntstatus:
sys.exit('Decompression failed, err: {}'.format(
tohex(ntstatus, 32)))
if ntFinalUncompressedSize.value != decompressed_size:
print 'Decompressed with a different size than original!'
with open(sys.argv[2], 'wb') as fout:
fout.write(bytearray(ntDecompressed))
print 'Lucky man, you have your prefetch file ready to be parsed!'
if __name__ == "__main__":
main()
@dfirfpi
Owner
dfirfpi commented Jun 21, 2015

Added checksum code. Now it's able to decompress files that uses MAM format, as Windows 10 Prefetch and SuperFetch files, together with Windows 8.1 SuperFetch files.

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