win32all140 - WNDCLASS heap corruption in module win32gui

[Alan Klietz]

While testing win32all140 with Python 2.2, I ran into a heap corruption
problem.  After much searching I tracked it down to an assignment to a
WNDCLASS object's lpfnWndProc attribute.  The problem is due to the wrong
member being DECREF'ed.   It was freeing lpszClassName when it should have
been freeing lpfnWndProc.

*************** int PyWNDCLASS::setattr(PyObject *self,
*** 520,526 ****
    return SetTCHAR(v, &pW->m_obClassName, &pW->m_WNDCLASS.lpszClassName);
   }
   if (strcmp("lpfnWndProc", name)==0) {
!   Py_XDECREF(pW->m_obClassName);
    if (!PyCallable_Check(v) && !PyDict_Check(v)) {
     PyErr_SetString(PyExc_TypeError, "lpfnWndProc must be callable, or a
dictionary");
     return -1;
--- 526,536 ----
    return SetTCHAR(v, &pW->m_obClassName, &pW->m_WNDCLASS.lpszClassName);
   }
   if (strcmp("lpfnWndProc", name)==0) {
!   //
!   // BUG: Decrementing the wrong object!! - AEK
!   //
!   //Py_XDECREF(pW->m_obClassName);
!   Py_XDECREF(pW->m_obWndProc);  // AEK
    if (!PyCallable_Check(v) && !PyDict_Check(v)) {
     PyErr_SetString(PyExc_TypeError, "lpfnWndProc must be callable, or a
dictionary");
     return -1;


Regards,
Alan Klietz
alank at algintech.NOSPAM.com  (remove .NOSPAM)