[project @ moraes-20021023115220-7b961936f27ecd5b]

[project @ 2002-10-23 04:52:20 by moraes]
Added Crypto.Util.winrandom.winrandom C extension code
to get randomness from Windows CryptGenRandom.

1 files changed, 86 insertions, 0 deletions

diff --git a/src/winrand.c b/src/winrand.c
new file mode 100644
index 0000000..00b6f4b
--- /dev/null
+++ b/src/winrand.c
@@ -0,0 +1,86 @@
+/* -*- C -*- */
+/*
+ * Uses Windows CryptoAPI CryptGenRandom to get random bytes
+ *
+ * Distribute and use freely; there are no restrictions on further 
+ * dissemination and usage except those imposed by the laws of your 
+ * country of residence.  This software is provided "as is" without
+ * warranty of fitness for use or suitability for any purpose, express
+ * or implied. Use at your own risk or not at all. 
+ *
+ */
+
+/* Author: Mark Moraes */
+
+#include "Python.h"
+
+#ifdef MS_WIN32
+
+#define _WIN32_WINNT 0x400
+#define WINSOCK
+
+#include <windows.h>
+#include <wincrypt.h>
+
+static char winrandom__doc__[] =
+"winrandom(nbytes): Returns nbytes of random data from Windows CryptGenRandom,"
+"a cryptographically strong pseudo-random generator using system entropy";
+
+static PyObject *
+winrandom(PyObject *self, PyObject *args)
+{
+	HCRYPTPROV hcp = 0;
+	int n, nbytes;
+	PyObject *res;
+	char *buf;
+	
+	if (!PyArg_ParseTuple(args, "i", &n)) {
+		return NULL;
+	}
+	/* Just in case char != BYTE */
+	nbytes = (n * sizeof(char)) / sizeof(BYTE);
+	if (nbytes <= 0) {
+		PyErr_SetString(PyExc_ValueError, "nbytes must be positive number");
+		return NULL;
+	}
+	if ((buf = (char *) PyMem_Malloc(nbytes)) == NULL)
+	    return PyErr_NoMemory();
+
+	if (! CryptAcquireContext(&hcp, NULL, NULL, PROV_RSA_FULL, 0)) {
+		PyErr_Format(PyExc_SystemError,
+			     "CryptAcquireContext failed, error %i",
+			     GetLastError());
+		PyMem_Free(buf);
+		return NULL;
+	} else if (! CryptGenRandom(hcp, (DWORD) nbytes, (BYTE *) buf)) {
+		PyErr_Format(PyExc_SystemError,
+			     "CryptGenRandom failed, error %i",
+			     GetLastError());
+		PyMem_Free(buf);
+		(void) CryptReleaseContext(hcp, 0);
+		return NULL;
+	}
+	if (! CryptReleaseContext(hcp, 0)) {
+		PyErr_Format(PyExc_SystemError,
+			     "CryptReleaseContext failed, error %i",
+			     GetLastError());
+		return NULL;
+	}
+	res = PyString_FromStringAndSize(buf, n);
+	PyMem_Free(buf);
+	return res;
+}
+
+static PyMethodDef WRMethods[] = {
+        {"winrandom", (PyCFunction) winrandom, METH_VARARGS, winrandom__doc__},
+	{NULL,      NULL}        /* Sentinel */
+};
+
+
+void
+initwinrandom()
+{
+	(void) Py_InitModule("winrandom", WRMethods);
+}
+
+#endif /* MS_WIN32 */