Tigris Trade contest - ali_shehab's results

Lines of code

https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Lock.sol#L84-L92

Vulnerability details

Impact

amount of tokens increased in the contract is updated when calling the lock function, and is decreased when calling the release function. However, since a user can add an amount when calling the extendLock function (see this function https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Lock.sol#L79-L92 ) ( see the comment mention that user can increase time and amount ), but the totalLocked[_asset] is not increased which can lead to totalLocked[_asset] to being in negative.

Proof of Concept

1. Bob locked 100 tokens for 10 days. totalLocked[_asset] will be 100.
2. Bob decided to extendLock and add more tokens so he added 50 tokens, so now Bob has 150 tokens, but the totalLocked[_asset] is still 100.
3. Now when he calls release either the totalLocked[_asset] will revert.

Tools Used

Vscode

Recommended Mitigation Steps

increase totalLocked[_asset] when calling the extendLock.