172 lines
5.2 KiB
Python
172 lines
5.2 KiB
Python
# ===================================================================
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#
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# Copyright (c) 2014, Legrandin <helderijs@gmail.com>
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in
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# the documentation and/or other materials provided with the
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# distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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# ===================================================================
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import imp
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from Crypto.Util.py3compat import byte_string
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from Crypto.Util._file_system import pycryptodome_filename
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try:
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from cffi import FFI
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ffi = FFI()
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null_pointer = ffi.NULL
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def load_lib(name, cdecl):
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"""Load a shared library and return a handle to it.
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@name, either an absolute path or the name of a library
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in the system search path.
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@cdecl, the C function declarations.
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"""
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lib = ffi.dlopen(name)
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ffi.cdef(cdecl)
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return lib
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def c_ulong(x):
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"""Convert a Python integer to unsigned long"""
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return x
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c_ulonglong = c_ulong
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def c_size_t(x):
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"""Convert a Python integer to size_t"""
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return x
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def create_string_buffer(size):
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"""Allocate the given amount of bytes (initially set to 0)"""
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return ffi.new("uint8_t[]", size)
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def get_c_string(c_string):
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"""Convert a C string into a Python byte sequence"""
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return ffi.string(c_string)
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def get_raw_buffer(buf):
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"""Convert a C buffer into a Python byte sequence"""
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return ffi.buffer(buf)[:]
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class VoidPointer(object):
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"""Model a newly allocated pointer to void"""
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def __init__(self):
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self._pp = ffi.new("void *[1]")
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def get(self):
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return self._pp[0]
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def address_of(self):
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return self._pp
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Array = ffi.new("uint8_t[1]").__class__.__bases__
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backend = "cffi"
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except ImportError:
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from ctypes import (CDLL, c_void_p, byref, c_ulong, c_ulonglong, c_size_t,
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create_string_buffer)
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from ctypes.util import find_library
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from _ctypes import Array
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null_pointer = None
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def load_lib(name, cdecl):
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import platform
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bits, linkage = platform.architecture()
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if "." not in name and not linkage.startswith("Win"):
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full_name = find_library(name)
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if full_name is None:
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raise OSError("Cannot load library '%s'" % name)
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name = full_name
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return CDLL(name)
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def get_c_string(c_string):
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return c_string.value
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def get_raw_buffer(buf):
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return buf.raw
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class VoidPointer(object):
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"""Model a newly allocated pointer to void"""
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def __init__(self):
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self._p = c_void_p()
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def get(self):
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return self._p
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def address_of(self):
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return byref(self._p)
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backend = "ctypes"
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class SmartPointer(object):
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"""Class to hold a non-managed piece of memory"""
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def __init__(self, raw_pointer, destructor):
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self._raw_pointer = raw_pointer
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self._destructor = destructor
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def get(self):
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return self._raw_pointer
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def release(self):
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rp, self._raw_pointer = self._raw_pointer, None
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return rp
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def __del__(self):
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if hasattr(self, "_raw_pointer") and self._raw_pointer is not None:
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self._destructor(self._raw_pointer)
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self._raw_pointer = None
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def load_pycryptodome_raw_lib(name, cdecl):
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"""Load a shared library and return a handle to it.
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@name, the name of the library expressed as a PyCryptodome module,
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for instance Crypto.Cipher._raw_cbc.
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@cdecl, the C function declarations.
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"""
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split = name.split(".")
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dir_comps, basename = split[:-1], split[-1]
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for ext, mod, typ in imp.get_suffixes():
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if typ == imp.C_EXTENSION:
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try:
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return load_lib(pycryptodome_filename(dir_comps, basename + ext), cdecl)
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except OSError:
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pass
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raise OSError("Cannot load native module '%s'" % name)
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def expect_byte_string(data):
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if not byte_string(data) and not isinstance(data, Array):
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raise TypeError("Only byte strings can be passed to C code")
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