# ===================================================================
#
# Copyright (c) 2014, Legrandin <helderijs@gmail.com>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in
# the documentation and/or other materials provided with the
# distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
# ===================================================================
import abc
import sys
from Cryptodome.Util.py3compat import byte_string
from Cryptodome.Util._file_system import pycryptodome_filename
#
# List of file suffixes for Python extensions
#
if sys.version_info[0] < 3:
import imp
extension_suffixes = []
for ext, mod, typ in imp.get_suffixes():
if typ == imp.C_EXTENSION:
extension_suffixes.append(ext)
else:
from importlib import machinery
extension_suffixes = machinery.EXTENSION_SUFFIXES
# Which types with buffer interface we support (apart from byte strings)
if sys.version_info[0] == 2 and sys.version_info[1] < 7:
_buffer_type = (bytearray)
else:
_buffer_type = (bytearray, memoryview)
class _VoidPointer(object):
@abc.abstractmethod
def get(self):
"""Return the memory location we point to"""
return
@abc.abstractmethod
def address_of(self):
"""Return a raw pointer to this pointer"""
return
try:
if sys.version_info[0] == 2 and sys.version_info[1] < 7:
raise ImportError("CFFI is only supported with Python 2.7+")
# Starting from v2.18, pycparser (used by cffi for in-line ABI mode)
# stops working correctly when PYOPTIMIZE==2 or the parameter -OO is
# passed. In that case, we fall back to ctypes.
# Note that PyPy ships with an old version of pycparser so we can keep
# using cffi there.
# See https://github.com/Legrandin/pycryptodome/issues/228
if '__pypy__' not in sys.builtin_module_names and sys.flags.optimize == 2:
raise ImportError("CFFI with optimize=2 fails due to pycparser bug.")
from cffi import FFI
ffi = FFI()
null_pointer = ffi.NULL
uint8_t_type = ffi.typeof(ffi.new("const uint8_t*"))
_Array = ffi.new("uint8_t[1]").__class__.__bases__
def load_lib(name, cdecl):
"""Load a shared library and return a handle to it.
@name, either an absolute path or the name of a library
in the system search path.
@cdecl, the C function declarations.
"""
lib = ffi.dlopen(name)
ffi.cdef(cdecl)
return lib
def c_ulong(x):
"""Convert a Python integer to unsigned long"""
return x
c_ulonglong = c_ulong
c_uint = c_ulong
def c_size_t(x):
"""Convert a Python integer to size_t"""
return x
def create_string_buffer(init_or_size, size=None):
"""Allocate the given amount of bytes (initially set to 0)"""
if isinstance(init_or_size, bytes):
size = max(len(init_or_size) + 1, size)
result = ffi.new("uint8_t[]", size)
result[:] = init_or_size
else:
if size:
raise ValueError("Size must be specified once only")
result = ffi.new("uint8_t[]", init_or_size)
return result
def get_c_string(c_string):
"""Convert a C string into a Python byte sequence"""
return ffi.string(c_string)
def get_raw_buffer(buf):
"""Convert a C buffer into a Python byte sequence"""
return ffi.buffer(buf)[:]
def c_uint8_ptr(data):
if isinstance(data, _buffer_type):
# This only works for cffi >= 1.7
return ffi.cast(uint8_t_type, ffi.from_buffer(data))
elif byte_string(data) or isinstance(data, _Array):
return data
else:
raise TypeError("Object type %s cannot be passed to C code" % type(data))
class VoidPointer_cffi(_VoidPointer):
"""Model a newly allocated pointer to void"""
def __init__(self):
self._pp = ffi.new("void *[1]")
def get(self):
return self._pp[0]
def address_of(self):
return self._pp
def VoidPointer():
return VoidPointer_cffi()
backend = "cffi"
except ImportError:
import ctypes
from ctypes import (CDLL, c_void_p, byref, c_ulong, c_ulonglong, c_size_t,
create_string_buffer, c_ubyte, c_uint)
from ctypes.util import find_library
from ctypes import Array as _Array
null_pointer = None
cached_architecture = []
def load_lib(name, cdecl):
if not cached_architecture:
# platform.architecture() creates a subprocess, so caching the
# result makes successive imports faster.
import platform
cached_architecture[:] = platform.architecture()
bits, linkage = cached_architecture
if "." not in name and not linkage.startswith("Win"):
full_name = find_library(name)
if full_name is None:
raise OSError("Cannot load library '%s'" % name)
name = full_name
return CDLL(name)
def get_c_string(c_string):
return c_string.value
def get_raw_buffer(buf):
return buf.raw
# ---- Get raw pointer ---
if sys.version_info[0] == 2 and sys.version_info[1] == 6:
# ctypes in 2.6 does not define c_ssize_t. Replacing it
# with c_size_t keeps the structure correctely laid out
_c_ssize_t = c_size_t
else:
_c_ssize_t = ctypes.c_ssize_t
_PyBUF_SIMPLE = 0
_PyObject_GetBuffer = ctypes.pythonapi.PyObject_GetBuffer
_PyBuffer_Release = ctypes.pythonapi.PyBuffer_Release
_py_object = ctypes.py_object
_c_ssize_p = ctypes.POINTER(_c_ssize_t)
# See Include/object.h for CPython
# and https://github.com/pallets/click/blob/master/click/_winconsole.py
class _Py_buffer(ctypes.Structure):
_fields_ = [
('buf', c_void_p),
('obj', ctypes.py_object),
('len', _c_ssize_t),
('itemsize', _c_ssize_t),
('readonly', ctypes.c_int),
('ndim', ctypes.c_int),
('format', ctypes.c_char_p),
('shape', _c_ssize_p),
('strides', _c_ssize_p),
('suboffsets', _c_ssize_p),
('internal', c_void_p)
]
# Extra field for CPython 2.6/2.7
if sys.version_info[0] == 2:
_fields_.insert(-1, ('smalltable', _c_ssize_t * 2))
def c_uint8_ptr(data):
if byte_string(data) or isinstance(data, _Array):
return data
elif isinstance(data, _buffer_type):
obj = _py_object(data)
buf = _Py_buffer()
_PyObject_GetBuffer(obj, byref(buf), _PyBUF_SIMPLE)
try:
buffer_type = c_ubyte * buf.len
return buffer_type.from_address(buf.buf)
finally:
_PyBuffer_Release(byref(buf))
else:
raise TypeError("Object type %s cannot be passed to C code" % type(data))
# ---
class VoidPointer_ctypes(_VoidPointer):
"""Model a newly allocated pointer to void"""
def __init__(self):
self._p = c_void_p()
def get(self):
return self._p
def address_of(self):
return byref(self._p)
def VoidPointer():
return VoidPointer_ctypes()
backend = "ctypes"
del ctypes
class SmartPointer(object):
"""Class to hold a non-managed piece of memory"""
def __init__(self, raw_pointer, destructor):
self._raw_pointer = raw_pointer
self._destructor = destructor
def get(self):
return self._raw_pointer
def release(self):
rp, self._raw_pointer = self._raw_pointer, None
return rp
def __del__(self):
try:
if self._raw_pointer is not None:
self._destructor(self._raw_pointer)
self._raw_pointer = None
except AttributeError:
pass
def load_pycryptodome_raw_lib(name, cdecl):
"""Load a shared library and return a handle to it.
@name, the name of the library expressed as a PyCryptodome module,
for instance Cryptodome.Cipher._raw_cbc.
@cdecl, the C function declarations.
"""
split = name.split(".")
dir_comps, basename = split[:-1], split[-1]
attempts = []
for ext in extension_suffixes:
try:
filename = basename + ext
return load_lib(pycryptodome_filename(dir_comps, filename),
cdecl)
except OSError as exp:
attempts.append("Trying '%s': %s" % (filename, str(exp)))
raise OSError("Cannot load native module '%s': %s" % (name, ", ".join(attempts)))
if sys.version_info[:2] != (2, 6):
def is_buffer(x):
"""Return True if object x supports the buffer interface"""
return isinstance(x, (bytes, bytearray, memoryview))
def is_writeable_buffer(x):
return (isinstance(x, bytearray) or
(isinstance(x, memoryview) and not x.readonly))
else:
def is_buffer(x):
return isinstance(x, (bytes, bytearray))
def is_writeable_buffer(x):
return isinstance(x, bytearray)