Submission Details
Impact:
Likelihood:
Unnecessary Self-Transfer Causing Gas Waste and Potential Reversion
Author Revealed upon completion
Root + Impact
Description
In the
collectUsdcFromSellingfunction, the contract unnecessarily transfers fees to itself usingusdc.safeTransfer(address(this), fees). Since the USDC is already in the contract from the buy function, this self-transfer wastes gas and could potentially cause unexpected reverts if the USDC token implementation doesn't handle self-transfers properly.
function collectUsdcFromSelling(uint256 _listingId) external onlySeller(_listingId) {
Listing memory listing = s_listings[_listingId];
require(!listing.isActive, "Listing must be inactive to collect USDC");
uint256 fees = _calculateFees(listing.price);
uint256 amountToSeller = listing.price - fees;
uint256 collateralToReturn = collateralForMinting[listing.tokenId];
totalFeesCollected += fees;
amountToSeller += collateralToReturn;
usdc.safeTransfer(address(this), fees); // @ self transfer
usdc.safeTransfer(msg.sender, amountToSeller);
}
Risk
Impact
This causes unnecessary gas consumption and could lead to transaction failures if the USDC implementation reverts on self-transfers.
Proof of Concept
no need
Recommended Mitigation
function collectUsdcFromSelling(uint256 _listingId) external onlySeller(_listingId) {
Listing memory listing = s_listings[_listingId];
require(!listing.isActive, "Listing must be inactive to collect USDC");
uint256 fees = _calculateFees(listing.price);
uint256 amountToSeller = listing.price - fees;
uint256 collateralToReturn = collateralForMinting[listing.tokenId];
totalFeesCollected += fees;
amountToSeller += collateralToReturn;
- usdc.safeTransfer(address(this), fees); // @ self transfer
usdc.safeTransfer(msg.sender, amountToSeller);
}
Rewards breakdown
nSLOC
253This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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