合约地址： https://etherscan.io/address/0x27f706edde3aD952EF647Dd67E24e38CD0803DD6#code
问题点.png
function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {
// mitigates the ERC20 short address attack
if(msg.data.length < (3 * 32) + 4) { throw; }
if (_value == 0) { return false; }
uint256 fromBalance = balances[_from];
uint256 allowance = allowed[_from][msg.sender];
//问题所在，判断条件写反了
bool sufficientFunds = fromBalance <= _value; //sufficientFunds = fromBalance >= _value;
bool sufficientAllowance = allowance <= _value; //sufficientAllowance = allowance >= _value;
bool overflowed = balances[_to] + _value > balances[_to];
//正确写法 if (sufficientFunds && sufficientAllowance && overflowed) {
if (sufficientFunds && sufficientAllowance && !overflowed) {
balances[_to] += _value;
balances[_from] -= _value;
allowed[_from][msg.sender] -= _value;
Transfer(_from, _to, _value);
return true;
} else { return false; }
}
`