Met - Unnecessary inaccuracy and wasted gas in FeeBuyback::submit

[sherlock-admin]

Met

low

Unnecessary inaccuracy and wasted gas in FeeBuyback::submit

Summary

Using total telcoin balance for referral payout instead of amount.

Vulnerability Detail

We already have the "amount" available right there, so there is no reason to use the total token balance as the transfer amount.

Impact

• If the token balance increased in one way or another, the given referral will get more than they are supposed to - and there is no reason for that
• Reading the token balance costs gas and it is done 2x in consecution, costing 2x the gas.
• Similar situation is a few lines lower, 79/80. But I understand that here you don't have the amount so it keeps the code simple

  Code Snippet

  https://github.com/sherlock-audit/2022-11-telcoin/blob/main/contracts/fee-buyback/FeeBuyback.sol#L62-L64

  Tool used

Manual Review

Recommendation

• Simply use amount in the approve and increaseClaimableBy instead of balanceOf().
• If you want to keep it this way, at least store the balance in a var to read it just once and save gas. Also applies to the two lines a bit lower - 79-80,