Added NEWS entry, plus:

Merged revisions 59925 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk/Modules/_ctypes

........
  r59925 | thomas.heller | 2008-01-11 20:34:06 +0100 (Fr, 11 Jan 2008) | 5 lines

  Raise an error instead of crashing with a segfault when a NULL
  function pointer is called.

  Will backport to release25-maint.
........

Lib/ctypes/test/test_funcptr.py

@@ -123,5 +123,11 @@ class CFuncPtrTestCase(unittest.TestCase):
         self.failUnlessEqual(strtok(None, "\n"), "c")
         self.failUnlessEqual(strtok(None, "\n"), None)
 
+    def test_NULL_funcptr(self):
+        tp = CFUNCTYPE(c_int)
+        func = tp() # NULL function pointer
+        # raise a ValueError when we try to call it
+        self.assertRaises(ValueError, func)
+
 if __name__ == '__main__':
     unittest.main()

Misc/NEWS

@@ -12,6 +12,8 @@ What's New in Python 2.5.2c1?
 Core and builtins
 -----------------
 
+- Prevent a segfault when a ctypes NULL function pointer is called.
+
 - Bug #1517: Possible segfault in lookup().
 
 - Issue #1638: %zd configure test fails on Linux.

Modules/_ctypes/_ctypes.c

@@ -3305,6 +3305,11 @@ CFuncPtr_call(CFuncPtrObject *self, PyObject *inargs, PyObject *kwds)
 
 
 	pProc = *(void **)self->b_ptr;
+	if (pProc == NULL) {
+		PyErr_SetString(PyExc_ValueError,
+				"attempt to call NULL function pointer");
+		return NULL;
+	}
 #ifdef MS_WIN32
 	if (self->index) {
 		/* It's a COM method */