From: Brett Cannon <bcannon@gmail.com>
Date: Mon, 10 Sep 2007 21:38:27 +0000 (+0000)
Subject: Fix a possible segfault from recursing too deep to get the repr of a list.
X-Git-Tag: v2.6a1~1316
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a0c05512ec071b98e8170c8cfe845bee6fc934da;p=python

Fix a possible segfault from recursing too deep to get the repr of a list.

Closes issue #1096.
---

diff --git a/Lib/test/list_tests.py b/Lib/test/list_tests.py
index 1c799d760e..a0011a46fb 100644
--- a/Lib/test/list_tests.py
+++ b/Lib/test/list_tests.py
@@ -46,6 +46,11 @@ class CommonTest(seq_tests.CommonTest):
         self.assertEqual(str(a2), "[0, 1, 2, [...], 3]")
         self.assertEqual(repr(a2), "[0, 1, 2, [...], 3]")
 
+        l0 = []
+        for i in xrange(sys.getrecursionlimit() + 100):
+            l0 = [l0]
+        self.assertRaises(RuntimeError, repr, l0)
+
     def test_print(self):
         d = self.type2test(xrange(200))
         d.append(d)
diff --git a/Misc/NEWS b/Misc/NEWS
index 99e4f07131..10f2c71e7c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@ What's New in Python 2.6 alpha 1?
 Core and builtins
 -----------------
 
+- Issue #1096: Prevent a segfault from getting the repr of a very deeply nested
+  list by using the recursion counter.
+
 - Issue #1202533: Fix infinite recursion calls triggered by calls to
   PyObject_Call() never calling back out to Python code to trigger recursion
   depth updates/checks.  Required the creation of a static RuntimeError
diff --git a/Objects/listobject.c b/Objects/listobject.c
index c0621dce91..92bad8c7c8 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -324,7 +324,10 @@ list_repr(PyListObject *v)
 	   so must refetch the list size on each iteration. */
 	for (i = 0; i < Py_Size(v); ++i) {
 		int status;
+		if (Py_EnterRecursiveCall(" while getting the repr of a list"))
+			goto Done;
 		s = PyObject_Repr(v->ob_item[i]);
+		Py_LeaveRecursiveCall();
 		if (s == NULL)
 			goto Done;
 		status = PyList_Append(pieces, s);