From df6b544ff6f342e8a64056e627867a70413bfdb0 Mon Sep 17 00:00:00 2001
From: Brett Cannon <brett@python.org>
Date: Thu, 3 Sep 2015 10:15:03 -0700
Subject: [PATCH] Issue #24913: Fix overrun error in deque.index().

Reported by John Leitch and Bryce Darling, patch by Raymond Hettinger.
---
 Lib/test/test_deque.py       | 5 +++++
 Misc/NEWS                    | 3 +++
 Modules/_collectionsmodule.c | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index b8585096841..87187161ab3 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -289,6 +289,11 @@ class TestBasic(unittest.TestCase):
                     else:
                         self.assertEqual(d.index(element, start, stop), target)
 
+    def test_insert_bug_24913(self):
+        d = deque('A' * 3)
+        with self.assertRaises(ValueError):
+            i = d.index("Hello world", 0, 4)
+
     def test_insert(self):
         # Test to make sure insert behaves like lists
         elements = 'ABCDEFGHI'
diff --git a/Misc/NEWS b/Misc/NEWS
index 8f34c5479e6..b1beeec473d 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -15,6 +15,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #24913: Fix overrun error in deque.index().
+  Found by John Leitch and Bryce Darling.
+
 
 What's New in Python 3.5.0 release candidate 2?
 ===============================================
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 830c5b83ebc..3856d83fb4e 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -924,6 +924,8 @@ deque_index(dequeobject *deque, PyObject *args)
         if (stop < 0)
             stop = 0;
     }
+    if (stop > Py_SIZE(deque))
+        stop = Py_SIZE(deque);
 
     for (i=0 ; i<stop ; i++) {
         if (i >= start) {