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/**
* xsalsa20module.cpp -- Python wrappers around Crypto++'s salsa
*/
#define PY_SSIZE_T_CLEAN
#include <Python.h>
#if (PY_VERSION_HEX < 0x02050000)
typedef int Py_ssize_t;
#endif
#include "xsalsa20module.hpp"
#ifdef DISABLE_EMBEDDED_CRYPTOPP
#include <cryptopp/salsa.h>
#else
#include <src-cryptopp/salsa.h>
#endif
static const char* const xsalsa20__doc__ = "_xsalsa20 cipher";
static PyObject *xsalsa20_error;
typedef struct {
PyObject_HEAD
/* internal */
// CryptoPP::CTR_Mode<CryptoPP::XSalsa20>::Encryption *e;
CryptoPP::XSalsa20::Encryption *e;
} XSalsa20;
PyDoc_STRVAR(XSalsa20__doc__,
"An XSalsa20 cipher object.\n\
\n\
This object encrypts/decrypts in CTR mode, using a counter that is initialized\n\
to zero when you instantiate the object. Successive calls to .process() will \n\
use the current counter and increment it.\n\
\n\
");
static PyObject *XSalsa20_process(XSalsa20* self, PyObject* msgobj) {
if(!PyString_CheckExact(msgobj)) {
PyStringObject* typerepr = reinterpret_cast<PyStringObject*>(PyObject_Repr(reinterpret_cast<PyObject*>(msgobj->ob_type)));
if (typerepr) {
PyErr_Format(xsalsa20_error, "Precondition violation: you are required to pass a Python string object (not a unicode, a subclass of string, or anything else), but you passed %s.", PyString_AS_STRING(reinterpret_cast<PyObject*>(typerepr)));
Py_DECREF(typerepr);
} else
PyErr_Format(xsalsa20_error, "Precondition violation: you are required to pass a Python string object (not a unicode, a subclass of string, or anything else).");
return NULL;
}
const char* msg;
Py_ssize_t msgsize;
if (PyString_AsStringAndSize(msgobj, const_cast<char**>(&msg), &msgsize))
return NULL;
assert (msgsize >= 0);
PyStringObject* result = reinterpret_cast<PyStringObject*>(PyString_FromStringAndSize(NULL, msgsize));
if (!result)
return NULL;
self->e->ProcessString(reinterpret_cast<byte*>(PyString_AS_STRING(result)), reinterpret_cast<const byte*>(msg), msgsize);
return reinterpret_cast<PyObject*>(result);
}
PyDoc_STRVAR(XSalsa20_process__doc__,
"Encrypt or decrypt the next bytes, returning the result.");
static PyMethodDef XSalsa20_methods[] = {
{"process", reinterpret_cast<PyCFunction>(XSalsa20_process), METH_O, XSalsa20_process__doc__},
{NULL},
};
static PyObject* XSalsa20_new(PyTypeObject* type, PyObject *args, PyObject *kwdict) {
XSalsa20* self = reinterpret_cast<XSalsa20*>(type->tp_alloc(type, 0));
if (!self)
return NULL;
self->e = NULL;
return reinterpret_cast<PyObject*>(self);
}
static void XSalsa20_dealloc(PyObject* self) {
if (reinterpret_cast<XSalsa20*>(self)->e)
delete reinterpret_cast<XSalsa20*>(self)->e;
self->ob_type->tp_free(self);
}
static int XSalsa20_init(PyObject* self, PyObject *args, PyObject *kwdict) {
static const char *kwlist[] = { "key", "iv", NULL};
const char *key = NULL;
Py_ssize_t keysize = 0;
const char *iv = NULL;
const char defaultiv[24] = {0};
Py_ssize_t ivsize = 0;
if (!PyArg_ParseTupleAndKeywords(args, kwdict, "t#|t#:XSalsa20.__init__", const_cast<char**>(kwlist), &key, &keysize, &iv, &ivsize))
return -1;
assert (keysize >= 0);
assert (ivsize >= 0);
if (!iv)
iv = defaultiv;
else if (ivsize != 24) {
PyErr_Format(xsalsa20_error, "Precondition violation: if an IV is passed, it must be exactly 24 bytes, not %d", ivsize);
return -1;
}
try {
reinterpret_cast<XSalsa20*>(self)->e = new CryptoPP::XSalsa20::Encryption(reinterpret_cast<const byte*>(key), keysize, reinterpret_cast<const byte*>(iv));
}
catch (CryptoPP::InvalidKeyLength le)
{
PyErr_Format(xsalsa20_error, "Precondition violation: you are required to pass a valid key size. Crypto++ gave this exception: %s", le.what());
return -1;
}
if (!reinterpret_cast<XSalsa20*>(self)->e)
{
PyErr_NoMemory();
return -1;
}
return 0;
}
static PyTypeObject XSalsa20_type = {
PyObject_HEAD_INIT(NULL)
0, /*ob_size*/
"_xsalsa.XSalsa20", /*tp_name*/
sizeof(XSalsa20), /*tp_basicsize*/
0, /*tp_itemsize*/
XSalsa20_dealloc, /*tp_dealloc*/
0, /*tp_print*/
0, /*tp_getattr*/
0, /*tp_setattr*/
0, /*tp_compare*/
0, /*tp_repr*/
0, /*tp_as_number*/
0, /*tp_as_sequence*/
0, /*tp_as_mapping*/
0, /*tp_hash*/
0, /*tp_call*/
0, /*tp_str*/
0, /*tp_getattro*/
0, /*tp_setattro*/
0, /*tp_as_buffer*/
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/
XSalsa20__doc__, /*tp_doc*/
0, /*tp_traverse*/
0, /*tp_clear*/
0, /*tp_richcompare*/
0, /*tp_weaklistoffset*/
0, /*tp_iter*/
0, /*tp_iternext*/
XSalsa20_methods, /*tp_methods*/
0, /*tp_members*/
0, /*tp_getset*/
0, /*tp_base*/
0, /*tp_dict*/
0, /*tp_descr_get*/
0, /*tp_descr_set*/
0, /*tp_dictoffset*/
XSalsa20_init, /*tp_init*/
0, /*tp_alloc*/
XSalsa20_new, /*tp_new*/
};
void init_xsalsa20(PyObject*const module)
{
if (PyType_Ready(&XSalsa20_type) < 0)
return;
Py_INCREF(&XSalsa20_type);
PyModule_AddObject(module, "xsalsa20_XSalsa20", (PyObject *)&XSalsa20_type);
xsalsa20_error = PyErr_NewException(const_cast<char*>("_xsalsa20.Error"), NULL, NULL);
PyModule_AddObject(module, "xsalsa20_Error", xsalsa20_error);
PyModule_AddStringConstant(module, "xsalsa20__doc__", const_cast<char*>(xsalsa20__doc__));
}
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