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🔒 Security: Fix reentrancy in MyToken transfer and transferFrom #55

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🔒 Security: Fix reentrancy in MyToken transfer and transferFrom #55

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222 changes: 112 additions & 110 deletions tutorial-22/contracts/MyToken.sol
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Original file line number Diff line number Diff line change
@@ -1,110 +1,112 @@
pragma solidity ^0.4.0;

import "./Token.sol";
import "./ERC20.sol";
import "./ERC223.sol";
import "./ERC223ReceivingContract.sol";
import "./SafeMath.sol";
import "./Addresses.sol";

contract MyToken is Token("MFT", "My Token", 0, 10000), ERC20, ERC223 {

using SafeMath for uint;
using Addresses for address;

function MyToken()
public {
_balanceOf[msg.sender] = _totalSupply;
}

function totalSupply()
public
view
returns (uint) {
return _totalSupply;
}

function balanceOf(address _addr)
public
view
returns (uint) {
return _balanceOf[_addr];
}

function transfer(address _to, uint _value)
public
returns (bool) {
return transfer(_to, _value, "");
}

function transfer(address _to, uint _value, bytes _data)
public
returns (bool) {
if (_value > 0 &&
_value <= _balanceOf[msg.sender]) {

if (_to.isContract()) {
ERC223ReceivingContract _contract = ERC223ReceivingContract(_to);
_contract.tokenFallback(msg.sender, _value, _data);
}

_balanceOf[msg.sender] = _balanceOf[msg.sender].sub(_value);
_balanceOf[_to] = _balanceOf[_to].add(_value);

return true;
}
return false;
}

function transferFrom(address _from, address _to, uint _value)
public
returns (bool) {
return transferFrom(_from, _to, _value, "");
}

function transferFrom(address _from, address _to, uint _value, bytes _data)
public
returns (bool) {
if (_allowances[_from][msg.sender] > 0 &&
_value > 0 &&
_allowances[_from][msg.sender] >= _value &&
_balanceOf[_from] >= _value) {

_allowances[_from][msg.sender] -= _value;

if (_to.isContract()) {
ERC223ReceivingContract _contract = ERC223ReceivingContract(_to);
_contract.tokenFallback(msg.sender, _value, _data);
}

_balanceOf[_from] = _balanceOf[_from].sub(_value);
_balanceOf[_to] = _balanceOf[_to].add(_value);

Transfer(_from, _to, _value);

return true;
}
return false;
}

function approve(address _spender, uint _value)
public
returns (bool) {
if (_balanceOf[msg.sender] >= _value) {
_allowances[msg.sender][_spender] = _value;
Approval(msg.sender, _spender, _value);
return true;
}
return false;
}

function allowance(address _owner, address _spender)
public
view
returns (uint) {
if (_allowances[_owner][_spender] < _balanceOf[_owner]) {
return _allowances[_owner][_spender];
}
return _balanceOf[_owner];
}
}
pragma solidity ^0.4.0;

import "./Token.sol";
import "./ERC20.sol";
import "./ERC223.sol";
import "./ERC223ReceivingContract.sol";
import "./SafeMath.sol";
import "./Addresses.sol";

contract MyToken is Token("MFT", "My Token", 0, 10000), ERC20, ERC223 {

using SafeMath for uint;
using Addresses for address;

function MyToken()
public {
_balanceOf[msg.sender] = _totalSupply;
}

function totalSupply()
public
view
returns (uint) {
return _totalSupply;
}

function balanceOf(address _addr)
public
view
returns (uint) {
return _balanceOf[_addr];
}

function transfer(address _to, uint _value)
public
returns (bool) {
return transfer(_to, _value, "");
}

function transfer(address _to, uint _value, bytes _data)
public
returns (bool) {
if (_value > 0 &&
_value <= _balanceOf[msg.sender]) {

_balanceOf[msg.sender] = _balanceOf[msg.sender].sub(_value);
_balanceOf[_to] = _balanceOf[_to].add(_value);

if (_to.isContract()) {
ERC223ReceivingContract _contract = ERC223ReceivingContract(_to);
_contract.tokenFallback(msg.sender, _value, _data);
}

Transfer(msg.sender, _to, _value);

return true;
}
return false;
}

function transferFrom(address _from, address _to, uint _value)
public
returns (bool) {
return transferFrom(_from, _to, _value, "");
}

function transferFrom(address _from, address _to, uint _value, bytes _data)
public
returns (bool) {
if (_allowances[_from][msg.sender] > 0 &&
_value > 0 &&
_allowances[_from][msg.sender] >= _value &&
_balanceOf[_from] >= _value) {

_allowances[_from][msg.sender] -= _value;

_balanceOf[_from] = _balanceOf[_from].sub(_value);
_balanceOf[_to] = _balanceOf[_to].add(_value);

if (_to.isContract()) {
ERC223ReceivingContract _contract = ERC223ReceivingContract(_to);
_contract.tokenFallback(msg.sender, _value, _data);
}

Transfer(_from, _to, _value);

return true;
}
return false;
}

function approve(address _spender, uint _value)
public
returns (bool) {
if (_balanceOf[msg.sender] >= _value) {
_allowances[msg.sender][_spender] = _value;
Approval(msg.sender, _spender, _value);
return true;
}
return false;
}

function allowance(address _owner, address _spender)
public
view
returns (uint) {
if (_allowances[_owner][_spender] < _balanceOf[_owner]) {
return _allowances[_owner][_spender];
}
return _balanceOf[_owner];
}
}