Submission Details
Severity:
Using long strings in require statements, will result in more gas
Summary
from solidity 0.8.4, we can use custom errors instead of long strings in require statements as custom errors takes less gas than the long strings in require statements.
Vulnerability Details
Proof of code to show the difference in gas cost is as follows:
Place below code in ChoosingRam.sol
code
error ChoosingRam__RamIsSelected();
error ChoosingRam__NotOrganiser();
modifier RamIsNotSelectedCustom() {
if (!isRamSelected) {
revert ChoosingRam__RamIsSelected();
}
_;
}
modifier OnlyOrganiserCustom() {
if (ramNFT.organiser() == msg.sender) {
revert ChoosingRam__NotOrganiser();
}
_;
}
function selectRamIfNotSelectedCustom() public RamIsNotSelectedCustom OnlyOrganiserCustom {
if (block.timestamp < 1728691200) {
revert ChoosingRam__TimeToBeLikeRamIsNotFinish();
}
if (block.timestamp > 1728777600) {
revert ChoosingRam__EventIsFinished();
}
uint256 random = uint256(keccak256(abi.encodePacked(block.timestamp, block.prevrandao))) % ramNFT.tokenCounter();
selectedRam = ramNFT.getCharacteristics(random).ram;
isRamSelected = true;
}
Place below code in Dussehra.t.sol and run the command - forge test --mt test__GasCostIsLowForCustomErrors -vvv
code
function test__GasCostIsLowForCustomErrors() public {
vm.txGasPrice(1);
uint256 gasStart = gasleft();
vm.expectRevert();
choosingRam.selectRamIfNotSelected();
uint256 gasEnd = gasleft();
uint256 gasUsedFirst = (gasStart - gasEnd) * tx.gasprice;
console.log("Gas cost of the long string errors", gasUsedFirst);
uint256 gasStartCustom = gasleft();
vm.expectRevert();
choosingRam.selectRamIfNotSelectedCustom();
uint256 gasEndCustom = gasleft();
uint256 gasUsedCustom = (gasStartCustom - gasEndCustom) * tx.gasprice;
console.log("Gas cost of custom errors", gasUsedCustom);
assert(gasUsedFirst > gasUsedCustom);
}
Impact
Increase in Gas cost
Tools Used
Foundry
Recommendations
Make below code changes in ChoosingRam.sol
code
+ error ChoosingRam__RamIsSelected();
+ error ChoosingRam__NotOrganiser();
modifier RamIsNotSelected() {
- require(!isRamSelected, "Ram is selected!");
+ if(!isRamSelected){
+ revert ChoosingRam__RamIsSelected();
+ }
_;
}
modifier OnlyOrganiser() {
- require(ramNFT.organiser() == msg.sender, "Only organiser can call this function!");
+ if(ramNFT.organiser() == msg.sender){
+ revert ChoosingRam__NotOrganiser();
+ }
_;
}
Updates
Lead Judging Commences
bube about 1 year ago
Submission Judgement Published Reason: Non-acceptable severity
Assigned finding tags:
Info/Gas/Invalid according to docs
Rewards breakdown
nSLOC
218This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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