KingNFT - The keeper will suffer continuing losses due to miss compensation for L1 rollup fees

[sherlock-admin4]

KingNFT

Medium

The keeper will suffer continuing losses due to miss compensation for L1 rollup fees

Summary

While keepers submits transactions to L2 EVM chains, they need to pay both L2 execution fee and L1 rollup fee. The current implementation only compensates the keeper based on L2 gas consumption, the keeper will suffer continuing losses due to miss compensation for L1 rollup fees.

Vulnerability Detail

As shown of the Arbitrum and Base(op-stack) docs: https://docs.arbitrum.io/arbos/l1-pricing https://docs.base.org/docs/fees/ https://docs.optimism.io/stack/transactions/fees#l1-data-fee Each L2 transaction costs both L2 execution fee and L1 rollup/data fee (for submitting L2 transaction to L1)

But current implementation only compensates the keeper the L2 gas consumption (L19).

File: contracts\process\GasProcess.sol
17:     function processExecutionFee(PayExecutionFeeParams memory cache) external {
18:         uint256 usedGas = cache.startGas - gasleft();
19:         uint256 executionFee = usedGas * tx.gasprice;
20:         uint256 refundFee;
21:         uint256 lossFee;
22:         if (executionFee > cache.userExecutionFee) {
23:             executionFee = cache.userExecutionFee;
24:             lossFee = executionFee - cache.userExecutionFee;
25:         } else {
26:             refundFee = cache.userExecutionFee - executionFee;
27:         }
28:         VaultProcess.transferOut(
29:             cache.from,
30:             AppConfig.getChainConfig().wrapperToken,
31:             address(this),
32:             cache.userExecutionFee
33:         );
34:         VaultProcess.withdrawEther(cache.keeper, executionFee);
35:         if (refundFee > 0) {
36:             VaultProcess.withdrawEther(cache.account, refundFee);
37:         }
38:         if (lossFee > 0) {
39:             CommonData.addLossExecutionFee(lossFee);
40:         }
41:     }

Impact

The keeper will suffer continuing losses on each transaction

Code Snippet

https://github.com/sherlock-audit/2024-05-elfi-protocol/blob/8a1a01804a7de7f73a04d794bf6b8104528681ad/elfi-perp-contracts/contracts/process/GasProcess.sol#L19

Tool used

Manual Review

Recommendation

Compensating L1 rollup fee as references of the above Arbitrum and Optimism docs:

[sherlock-admin2]

The protocol team fixed this issue in the following PRs/commits: https://github.com/0xCedar/elfi-perp-contracts/pull/48

[sherlock-admin2]

The Lead Senior Watson signed off on the fix.