ElasticSwap contest - Jujic's results

Handle

Jujic

Vulnerability details

Impact

For the arithmetic operations that will never over/underflow, using the unchecked directive (Solidity v0.8 has default overflow/underflow checks) can save some gas from the unnecessary internal over/underflow checks.

Proof of Concept

https://github.com/code-423n4/2022-01-elasticswap/blob/d107a198c0d10fbe254d69ffe5be3e40894ff078/elasticswap/src/contracts/Exchange.sol#L228

if (quoteTokenQtyToReturn > internalBalances.quoteTokenReserveQty) {
            internalBalances.quoteTokenReserveQty = 0;
        } else {
            internalBalances.quoteTokenReserveQty -= quoteTokenQtyToReturn;
        }

Tools Used

Remix

Recommended Mitigation Steps

Consider using 'unchecked' where it is safe to do so.

Handle

Jujic

Vulnerability details

Impact

Shortening revert strings to fit in 32 bytes will decrease deployment time gas and will decrease runtime gas when the revert condition has been met.

There are several other places throughout the codebase where the same optimization can be used.

Proof of Concept

https://github.com/code-423n4/2022-01-elasticswap/blob/d107a198c0d10fbe254d69ffe5be3e40894ff078/elasticswap/src/contracts/Exchange.sol#L179

 require(
            _baseTokenQtyMin > 0 && _quoteTokenQtyMin > 0,
            "Exchange: MINS_MUST_BE_GREATER_THAN_ZERO"
        );

Tools Used

https://planetcalc.com/9029/

Recommended Mitigation Steps

Shorten the revert strings to fit in 32 bytes.

Handle

Jujic

Vulnerability details

Impact

I think this check should be inclusive:

Proof of Concept

https://github.com/code-423n4/2022-01-elasticswap/blob/d107a198c0d10fbe254d69ffe5be3e40894ff078/elasticswap/src/libraries/MathLib.sol#L676

require(
            quoteTokenQty > _quoteTokenQtyMin,
            "MathLib: INSUFFICIENT_QUOTE_TOKEN_QTY"
        );

Tools Used

Remix

Recommended Mitigation Steps

require(
            quoteTokenQty >= _quoteTokenQtyMin,
            "MathLib: INSUFFICIENT_QUOTE_TOKEN_QTY"
        );