CodeHawks Escrow Contract - Competition Details
Cyfrin
Foundry
40,000 USDC
View results
Previous Next
Submission Details
Severity: gas

Gas Optimizations

Mlome

Gas Optimizations

Issue Instances
[GAS-01] Remove useless check 1
[GAS-02] Function used only once can be inlined 1
[GAS-03] Setting the constructor to payable 1

[GAS-01] Remove useless check

In the Escrow.sol contract's constructor the buyer can not be address(0) because it is passed as msg.sender in EscrowFactory::newEscrow.

File: EscrowFactory.sol
​
40: Escrow escrow = new Escrow{salt: salt}(
price,
tokenContract,
msg.sender,
seller,
arbiter,
arbiterFee
);

Therefore the following check can be removed:

File: Escrow.sol
​
41: if (buyer == address(0)) revert Escrow__BuyerZeroAddress();
​

[GAS-02] Function used only once can be inlined

The function EscrowFactory::computeEscrowAddress is used only once, so it can be inlined to save the gas of a function call. The function computeEscrowAddress() can be removed and newEscrow() modified as such:

File: EscrowFactory.sol
​
20: function newEscrow(
uint256 price,
IERC20 tokenContract,
address seller,
address arbiter,
uint256 arbiterFee,
bytes32 salt
) external returns (IEscrow) {
+ /// @dev See https://docs.soliditylang.org/en/latest/control-structures.html#salted-contract-creations-create2
+ address computedAddress = address(
+ uint160(
+ uint256(
+ keccak256(
+ abi.encodePacked(
+ bytes1(0xff),
+ deployer,
+ salt,
+ keccak256(
+ abi.encodePacked(
+ byteCode, abi.encode(price, tokenContract, buyer, seller, arbiter, arbiterFee)
+ )
+ )
+ )
+ )
+ )
+ )
+ );
tokenContract.safeTransferFrom(msg.sender, computedAddress, price);
Escrow escrow = new Escrow{salt: salt}(
price,
tokenContract,
msg.sender,
seller,
arbiter,
arbiterFee
);
if (address(escrow) != computedAddress) {
revert EscrowFactory__AddressesDiffer();
}
emit EscrowCreated(address(escrow), msg.sender, seller, arbiter);
return escrow;
}
​

[GAS-03] Setting the constructor to payable

Saves ~13 gas per instance

Instance (1):

File: Escrow.sol
32: constructor(
uint256 price,
IERC20 tokenContract,
address buyer,
address seller,
address arbiter,
uint256 arbiterFee
) {
​

Support

FAQs

Can't find an answer? Chat with us on Discord, Twitter or Linkedin.