有道安全题叫Elevator，意思是说要攻击这个合约，修改里面的top变量，使得top的值为true。我们先看原题：// SPDX-License-Identifier: MIT pragma solidity ^0.8.0; interface Building { function isLastFloor(uint256) external returns (bool); } contract Elevator { bool public top; uint256 public floor; function goTo(uint256 _floor) public { Building building = Building(msg.sender); if (!building.isLastFloor(_floor)) { floor = _floor; top = building.isLastFloor(floor); } } } 首先需要building.isLastFloor(_floor) == false，才能进到if内部，top = building.isLas...