v8/test/mjsunit/regress/regress-crbug-702058-3.js
bmeurer 9224d5d1bc [csa] Bailout to the runtime for ToInteger conversion in Array.p.indexOf.
The fast-path for Array.prototype.indexOf first checks whether the
receiver is a fast-mode JSArray (and there are no elements in the
prototype chain in case of holey arrays), then loads the known
JSArray::length, and afterwards calls ToInteger on the fromIndex.

But this ToInteger(fromIndex) call can cause arbitrary side effects if
the fromIndex is a JSReceiver, in particular it can invalidate the
assumptions about the fast-mode of the receiver and the length. In the
worst case this leads to OOB memory access.

Quick-fix is to bailout to the runtime if the fromIndex is neither a Smi
nor undefined, which represents the common cases.

R=jarin@chromium.org
BUG=chromium:702058

Review-Url: https://codereview.chromium.org/2756663002
Cr-Commit-Position: refs/heads/master@{#43843}
2017-03-16 06:53:09 +00:00

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JavaScript

// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --allow-natives-syntax
var arr = [];
for (var i = 0; i < 100000; i++) arr[i] = [];
var fromIndex = {valueOf: function() { arr.length = 0; }};
arr.indexOf({}, fromIndex);