Fei Protocol contest - TomFrenchBlockchain's results

Handle

TomFrench

Vulnerability details

Impact

gas savings

Proof of Concept

Here we perform a check against zero every time we requery the oracle even though it's very unlikely to be zero again after initialisation.

https://github.com/code-423n4/2021-11-fei/blob/add34324513b863f58e4ef7b3cd0c12d776dbb7f/contracts/TRIBERagequit.sol#L117-L129

Recommended Mitigation Steps

Swap if statements to avoid redundant checking

Handle

TomFrench

Vulnerability details

Impact

Deployment gas

Proof of Concept

Both contracts have storage variables which are explicitly set to zero on construction.

https://github.com/code-423n4/2021-11-fei/blob/add34324513b863f58e4ef7b3cd0c12d776dbb7f/contracts/TRIBERagequit.sol#L20-L31

These can be just declared like

    bool public party0Accepted; // rgt timelock accepted
    bool public party1Accepted; // tribe timelock accepted

And will default to being false, etc.

It's well known that an explicit assignment to zero/false results in higher deployment costs than the above so doing so just spends gas for no reason.

Recommended Mitigation Steps

Make use of storage variables defaulting to zero/false.