Zkswap Finance - Audit

In the contract `ZFFactory` the role `feeToSetter` has authority over the functions shown in the diagram below. Any compromise to the `feeToSetter` account may allow the hacker to take advantage of this authority. - set the address of `feeTo` - set `swapFee` - set protocol fee factor - set the address of `pendingFeeToSetter`, who can accept the `feeToSetter` role - set swap fee point override for a pair  In the contract `ZFFactory` the role `pendingFeeToSetter` has authority over the functions shown in the diagram below. Any compromise to the `pendingFeeToSetter` account may allow the hacker to take advantage of this authority. - accept the `feeToSetter` role  In the contract `ZFPair` the role `factory` has authority over the functions shown in the diagram below. Any compromise to the `factory` account may allow the hacker to take advantage of this authority. - set the `swapFeeOverride` 

We note that the variable `indexedPairs` is used to keep track of users who add liquidity, but does not remove the user from the variable `indexedPairs` after the user removes liquidity completely.

The `setProtocolFeeFactor()` function allows the `feeToSetter` to set the minimum `protocolFeeFactor` as 2, which means half of the fee will be charged and sent to the `_feeTo`. The popular DEXs Uniswap V2 charges 1/6 and Pancake charges 1/4. ```solidity function _getFeeLiquidity(uint _totalSupply, uint _rootK2, uint _rootK1, uint8 _feeFactor) private pure returns (uint) { uint numerator = _totalSupply * (_rootK2 - _rootK1); uint denominator = (_feeFactor - 1) * _rootK2 + _rootK1; return numerator / denominator; } ```

Addresses are not validated before assignment or external calls, potentially allowing the use of zero addresses and leading to unexpected behavior or vulnerabilities. For example, transferring tokens to a zero address can result in a permanent loss of those tokens. ```solidity=34 feeToSetter = _feeToSetter; ``` - `_feeToSetter` is not zero-checked before being used. --- ```solidity=69 feeTo = _feeTo; ``` - `_feeTo` is not zero-checked before being used. --- ```solidity=86 pendingFeeToSetter = _feeToSetter; ``` - `_feeToSetter` is not zero-checked before being used. --- ```solidity=53 token0 = _token0; ``` - `_token0` is not zero-checked before being used. --- ```solidity=54 token1 = _token1; ``` - `_token1` is not zero-checked before being used. --- ```solidity=19 factory = _factory; ``` - `_factory` is not zero-checked before being used. --- ```solidity=20 WETH = _WETH; ``` - `_WETH` is not zero-checked before being used.

Type casting refers to changing an variable of one data type into another. The code contains an unsafe cast between integer types, which may result in unexpected truncation or sign flipping of the value. ```solidity=109 principal0: uint112(liquidity * _reserve0 / _totalSupply), ``` Casted expression `liquidity * _reserve0 / _totalSupply` has estimated range [0, 115792089237316195423570985008687907853269984665640564039457584007913129639935] but target type `uint112` has range [0, 5192296858534827628530496329220095]. --- ```solidity=110 principal1: uint112(liquidity * _reserve1 / _totalSupply), ``` Casted expression `liquidity * _reserve1 / _totalSupply` has estimated range [0, 115792089237316195423570985008687907853269984665640564039457584007913129639935] but target type `uint112` has range [0, 5192296858534827628530496329220095]. --- ```solidity=118 principal0: uint112(liquidity * _reserve0 / _totalSupply), ``` Casted expression `liquidity_scope_0 * _reserve0 / _totalSupply` has estimated range [0, 115792089237316195423570985008687907853269984665640564039457584007913129639935] but target type `uint112` has range [0, 5192296858534827628530496329220095]. --- ```solidity=119 principal1: uint112(liquidity * _reserve1 / _totalSupply), ``` Casted expression `liquidity_scope_0 * _reserve1 / _totalSupply` has estimated range [0, 115792089237316195423570985008687907853269984665640564039457584007913129639935] but target type `uint112` has range [0, 5192296858534827628530496329220095].