diff options
Diffstat (limited to 'src/pycryptopp/cipher/xsalsa20module.cpp')
| -rw-r--r-- | src/pycryptopp/cipher/xsalsa20module.cpp | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/src/pycryptopp/cipher/xsalsa20module.cpp b/src/pycryptopp/cipher/xsalsa20module.cpp new file mode 100644 index 0000000..ab29787 --- /dev/null +++ b/src/pycryptopp/cipher/xsalsa20module.cpp @@ -0,0 +1,176 @@ +/** + * 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__)); +} |