From: Guido van Rossum <guido@python.org>
Date: Fri, 22 May 1998 00:53:47 +0000 (+0000)
Subject: Make sure that no use of a function pointer gotten from a
X-Git-Tag: v1.5.2a1~568
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7df115de652afa918f35b1028534ed621c45160d;p=thirdparty%2FPython%2Fcpython.git

Make sure that no use of a function pointer gotten from a
tp_as_sequence or tp_as_mapping structure is made without checking it
for NULL first.
---

diff --git a/Modules/stropmodule.c b/Modules/stropmodule.c
index 73c2d8568324..2d11851e7c07 100644
--- a/Modules/stropmodule.c
+++ b/Modules/stropmodule.c
@@ -274,13 +274,15 @@ strop_joinfields(self, args)
 		}
 		return res;
 	}
-	else if (!PySequence_Check(seq)) {
+
+	if (seq->ob_type->tp_as_sequence == NULL ||
+		 (getitemfunc = seq->ob_type->tp_as_sequence->sq_item) == NULL)
+	{
 		PyErr_SetString(PyExc_TypeError,
 				"first argument must be a sequence");
 		return NULL;
 	}
-	/* type safe */
-	getitemfunc = seq->ob_type->tp_as_sequence->sq_item;
+	/* This is now type safe */
 	for (i = 0; i < seqlen; i++) {
 		PyObject *item = getitemfunc(seq, i);
 		if (!item || !PyString_Check(item)) {