$OpenBSD: patch-Modules_zlibmodule_c,v 1.1 2008/08/06 03:23:31 djm Exp $
--- Modules/zlibmodule.c.orig	Wed Nov 21 11:44:57 2007
+++ Modules/zlibmodule.c	Tue Aug  5 18:18:52 2008
@@ -774,6 +774,10 @@ PyZlib_unflush(compobject *self, PyObject *args)
 
     if (!PyArg_ParseTuple(args, "|i:flush", &length))
 	return NULL;
+    if (length <= 0) {
+	PyErr_SetString(PyExc_ValueError, "length must be greater than zero");
+	return NULL;
+    }
     if (!(retval = PyString_FromStringAndSize(NULL, length)))
 	return NULL;