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- Issue #13703: oCERT-2011-003: add -R command-line option and PYTHONHASHSEED

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environment variable, to provide an opt-in way to protect against denial of
  service attacks due to hash collisions within the dict and set types.  Patch
  by David Malcolm, based on work by Victor Stinner.
This commit is contained in:
Barry Warsaw 2012-02-20 20:42:21 -05:00
parent f5a5beb339
commit 1e13eb084f
27 changed files with 706 additions and 152 deletions
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125
Modules/posixmodule.c
View file

@ -8371,117 +8371,35 @@ posix_getloadavg(PyObject *self, PyObject *noargs)
}
#endif
#ifdef MS_WINDOWS
PyDoc_STRVAR(win32_urandom__doc__,
PyDoc_STRVAR(posix_urandom__doc__,
"urandom(n) -> str\n\n\
Return a string of n random bytes suitable for cryptographic use.");
Return n random bytes suitable for cryptographic use.");
typedef BOOL (WINAPI *CRYPTACQUIRECONTEXTA)(HCRYPTPROV *phProv,\
LPCSTR pszContainer, LPCSTR pszProvider, DWORD dwProvType,\
DWORD dwFlags );
typedef BOOL (WINAPI *CRYPTGENRANDOM)(HCRYPTPROV hProv, DWORD dwLen,\
BYTE *pbBuffer );
static CRYPTGENRANDOM pCryptGenRandom = NULL;
/* This handle is never explicitly released. Instead, the operating
system will release it when the process terminates. */
static HCRYPTPROV hCryptProv = 0;
static PyObject*
win32_urandom(PyObject *self, PyObject *args)
static PyObject *
posix_urandom(PyObject *self, PyObject *args)
{
int howMany;
PyObject* result;
Py_ssize_t size;
PyObject *result;
int ret;
/* Read arguments */
if (! PyArg_ParseTuple(args, "i:urandom", &howMany))
/* Read arguments */
if (!PyArg_ParseTuple(args, "n:urandom", &size))
return NULL;
if (howMany < 0)
if (size < 0)
return PyErr_Format(PyExc_ValueError,
"negative argument not allowed");
result = PyBytes_FromStringAndSize(NULL, size);
if (result == NULL)
return NULL;
if (hCryptProv == 0) {
HINSTANCE hAdvAPI32 = NULL;
CRYPTACQUIRECONTEXTA pCryptAcquireContext = NULL;
/* Obtain handle to the DLL containing CryptoAPI
This should not fail */
hAdvAPI32 = GetModuleHandle("advapi32.dll");
if(hAdvAPI32 == NULL)
return win32_error("GetModuleHandle", NULL);
/* Obtain pointers to the CryptoAPI functions
This will fail on some early versions of Win95 */
pCryptAcquireContext = (CRYPTACQUIRECONTEXTA)GetProcAddress(
hAdvAPI32,
"CryptAcquireContextA");
if (pCryptAcquireContext == NULL)
return PyErr_Format(PyExc_NotImplementedError,
"CryptAcquireContextA not found");
pCryptGenRandom = (CRYPTGENRANDOM)GetProcAddress(
hAdvAPI32, "CryptGenRandom");
if (pCryptGenRandom == NULL)
return PyErr_Format(PyExc_NotImplementedError,
"CryptGenRandom not found");
/* Acquire context */
if (! pCryptAcquireContext(&hCryptProv, NULL, NULL,
PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
return win32_error("CryptAcquireContext", NULL);
}
/* Allocate bytes */
result = PyString_FromStringAndSize(NULL, howMany);
if (result != NULL) {
/* Get random data */
memset(PyString_AS_STRING(result), 0, howMany); /* zero seed */
if (! pCryptGenRandom(hCryptProv, howMany, (unsigned char*)
PyString_AS_STRING(result))) {
Py_DECREF(result);
return win32_error("CryptGenRandom", NULL);
}
ret = _PyOS_URandom(PyBytes_AS_STRING(result),
PyBytes_GET_SIZE(result));
if (ret == -1) {
Py_DECREF(result);
return NULL;
}
return result;
}
#endif
#ifdef __VMS
/* Use openssl random routine */
#include <openssl/rand.h>
PyDoc_STRVAR(vms_urandom__doc__,
"urandom(n) -> str\n\n\
Return a string of n random bytes suitable for cryptographic use.");
static PyObject*
vms_urandom(PyObject *self, PyObject *args)
{
int howMany;
PyObject* result;
/* Read arguments */
if (! PyArg_ParseTuple(args, "i:urandom", &howMany))
return NULL;
if (howMany < 0)
return PyErr_Format(PyExc_ValueError,
"negative argument not allowed");
/* Allocate bytes */
result = PyString_FromStringAndSize(NULL, howMany);
if (result != NULL) {
/* Get random data */
if (RAND_pseudo_bytes((unsigned char*)
PyString_AS_STRING(result),
howMany) < 0) {
Py_DECREF(result);
return PyErr_Format(PyExc_ValueError,
"RAND_pseudo_bytes");
}
}
return result;
}
#endif
static PyMethodDef posix_methods[] = {
{"access", posix_access, METH_VARARGS, posix_access__doc__},
@ -8787,12 +8705,7 @@ static PyMethodDef posix_methods[] = {
#ifdef HAVE_GETLOADAVG
{"getloadavg", posix_getloadavg, METH_NOARGS, posix_getloadavg__doc__},
#endif
#ifdef MS_WINDOWS
{"urandom", win32_urandom, METH_VARARGS, win32_urandom__doc__},
#endif
#ifdef __VMS
{"urandom", vms_urandom, METH_VARARGS, vms_urandom__doc__},
#endif
{"urandom", posix_urandom, METH_VARARGS, posix_urandom__doc__},
{NULL, NULL} /* Sentinel */
};