Anirruth - Gas could get stuck in the contract

[sherlock-admin2]

Anirruth

Medium

Gas could get stuck in the contract

Summary

User could lose the extra gas fee they sent due to incorrect return value in _payNative function.

Root Cause

https://github.com/sherlock-audit/2024-09-orderly-network-solana-contract/blob/main/sol-cc/contracts/layerzerolabs/lz-evm-oapp-v2/contracts/oapp/OAppSenderUpgradeable.sol#L110-L114
The _payNative function has the following check :

function _payNative(uint256 _nativeFee) internal virtual returns (uint256 nativeFee) {
    // enable the OApp to pay the native fee
    if (msg.value < _nativeFee && address(this).balance < _nativeFee) revert NotEnoughNative(msg.value);
    return _nativeFee; //@audit should return msg.value so that the extra gas gets refunded to the user
}

As the function has && not || the user will provide the required gas fee, so the extra fee (_nativeFee - msg.value) paid by the user will get stuck in the contract.

Internal pre-conditions

None

External pre-conditions

None

Impact

User loses the entitled refund of gas fee.

Mitigation

Refund the extra fee (_nativeFee - msg.value) paid by the user.