1 files changed, 173 insertions, 0 deletions
diff --git a/src/lib/tlslite/utils/entropy.c b/src/lib/tlslite/utils/entropy.c
new file mode 100755
index 000000000..c627794d2
--- /dev/null
+++ b/src/lib/tlslite/utils/entropy.c
@@ -0,0 +1,173 @@
+
+#include "Python.h"
+
+
+#ifdef MS_WINDOWS
+
+/* The following #define is not needed on VC6 with the Platform SDK, and it
+may not be needed on VC7, I'm not sure.  I don't think it hurts anything.*/
+#define _WIN32_WINNT 0x0400
+
+#include <windows.h>
+
+
+typedef BOOL (WINAPI *CRYPTACQUIRECONTEXTA)(HCRYPTPROV *phProv,\
+              LPCSTR pszContainer, LPCSTR pszProvider, DWORD dwProvType,\
+              DWORD dwFlags );
+typedef BOOL (WINAPI *CRYPTGENRANDOM)(HCRYPTPROV hProv, DWORD dwLen,\
+              BYTE *pbBuffer );
+typedef BOOL (WINAPI *CRYPTRELEASECONTEXT)(HCRYPTPROV hProv,\
+              DWORD dwFlags);
+
+
+static PyObject* entropy(PyObject *self, PyObject *args)
+{
+    int howMany = 0;
+    HINSTANCE hAdvAPI32 = NULL;
+    CRYPTACQUIRECONTEXTA pCryptAcquireContextA = NULL;
+    CRYPTGENRANDOM pCryptGenRandom = NULL;
+    CRYPTRELEASECONTEXT pCryptReleaseContext = NULL;
+    HCRYPTPROV hCryptProv = 0;
+    unsigned char* bytes = NULL;
+    PyObject* returnVal = NULL;
+
+
+    /* Read arguments */
+    if (!PyArg_ParseTuple(args, "i", &howMany))
+        return(NULL);
+
+	/* Obtain handle to the DLL containing CryptoAPI
+	   This should not fail	*/
+	if( (hAdvAPI32 = GetModuleHandle("advapi32.dll")) == NULL) {
+        PyErr_Format(PyExc_SystemError,
+            "Advapi32.dll not found");
+        return NULL;
+	}
+
+	/* Obtain pointers to the CryptoAPI functions
+	   This will fail on some early version of Win95 */
+	pCryptAcquireContextA = (CRYPTACQUIRECONTEXTA)GetProcAddress(hAdvAPI32,\
+	                        "CryptAcquireContextA");
+	pCryptGenRandom = (CRYPTGENRANDOM)GetProcAddress(hAdvAPI32,\
+	                  "CryptGenRandom");
+	pCryptReleaseContext = (CRYPTRELEASECONTEXT) GetProcAddress(hAdvAPI32,\
+	                       "CryptReleaseContext");
+	if (pCryptAcquireContextA == NULL || pCryptGenRandom == NULL ||
+	                                     pCryptReleaseContext == NULL) {
+        PyErr_Format(PyExc_NotImplementedError,
+            "CryptoAPI not available on this version of Windows");
+        return NULL;
+	}
+
+    /* Allocate bytes */
+    if ((bytes = (unsigned char*)PyMem_Malloc(howMany)) == NULL)
+        return PyErr_NoMemory();
+
+
+    /* Acquire context */
+    if(!pCryptAcquireContextA(&hCryptProv, NULL, NULL, PROV_RSA_FULL,
+                            CRYPT_VERIFYCONTEXT)) {
+        PyErr_Format(PyExc_SystemError,
+                     "CryptAcquireContext failed, error %d", GetLastError());
+        PyMem_Free(bytes);
+        return NULL;
+    }
+
+    /* Get random data */
+    if(!pCryptGenRandom(hCryptProv, howMany, bytes)) {
+        PyErr_Format(PyExc_SystemError,
+                     "CryptGenRandom failed, error %d", GetLastError());
+        PyMem_Free(bytes);
+        CryptReleaseContext(hCryptProv, 0);
+        return NULL;
+    }
+
+    /* Build return value */
+    returnVal = Py_BuildValue("s#", bytes, howMany);
+    PyMem_Free(bytes);
+
+    /* Release context */
+    if (!pCryptReleaseContext(hCryptProv, 0)) {
+        PyErr_Format(PyExc_SystemError,
+                     "CryptReleaseContext failed, error %d", GetLastError());
+        return NULL;
+    }
+
+    return returnVal;
+}
+
+#elif defined(HAVE_UNISTD_H) && defined(HAVE_FCNTL_H)
+
+#include <unistd.h>
+#include <fcntl.h>
+
+static PyObject* entropy(PyObject *self, PyObject *args)
+{
+    int howMany;
+    int fd;
+    unsigned char* bytes = NULL;
+    PyObject* returnVal = NULL;
+
+
+    /* Read arguments */
+    if (!PyArg_ParseTuple(args, "i", &howMany))
+        return(NULL);
+
+    /* Allocate bytes */
+    if ((bytes = (unsigned char*)PyMem_Malloc(howMany)) == NULL)
+        return PyErr_NoMemory();
+
+    /* Open device */
+    if ((fd = open("/dev/urandom", O_RDONLY, 0)) == -1) {
+        PyErr_Format(PyExc_NotImplementedError,
+            "No entropy source found");
+        PyMem_Free(bytes);
+        return NULL;
+    }
+
+    /* Get random data */
+    if (read(fd, bytes, howMany) < howMany) {
+        PyErr_Format(PyExc_SystemError,
+            "Reading from /dev/urandom failed");
+        PyMem_Free(bytes);
+        close(fd);
+        return NULL;
+    }
+
+    /* Build return value */
+    returnVal = Py_BuildValue("s#", bytes, howMany);
+    PyMem_Free(bytes);
+
+    /* Close device */
+    close(fd);
+
+    return returnVal;
+}
+
+#else
+
+static PyObject* entropy(PyObject *self, PyObject *args)
+{
+    PyErr_Format(PyExc_NotImplementedError,
+            "Function not supported");
+    return NULL;
+}
+
+#endif
+
+
+
+/* List of functions exported by this module */
+
+static struct PyMethodDef entropy_functions[] = {
+    {"entropy", (PyCFunction)entropy, METH_VARARGS, "Return a string of random bytes produced by a platform-specific\nentropy source."},
+    {NULL,  NULL}        /* Sentinel */
+};
+
+
+/* Initialize this module. */
+
+PyMODINIT_FUNC initentropy(void)
+{
+    Py_InitModule("entropy", entropy_functions);
+}
+\ No newline at end of file