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code-423n4 / 2022-05-opensea-seaport-findings

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Gas Optimizations #157

Open code423n4 opened 2 years ago

code423n4 commented 2 years ago

Issue: Variables should not be initialized to their default values

Explanation: Initializing uint variables to their default value of zero is unnecessary and costs gas

extraCeiling is initialized to zero in both lines below:

https://github.com/code-423n4/2022-05-opensea-seaport/blob/7c082637d9273deb42e551c74a578151cefd8448/contracts/lib/AmountDeriver.sol#L44

https://github.com/code-423n4/2022-05-opensea-seaport/blob/7c082637d9273deb42e551c74a578151cefd8448/reference/lib/ReferenceAmountDeriver.sol#L46

            uint256 extraCeiling = 0;

Change to uint256 extraCeiling; in both cases

i (or j) is initialized to zero in all 37 lines below:

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/BasicOrderFulfiller.sol#L948

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/BasicOrderFulfiller.sol#L1040

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/conduit/Conduit.sol#L66

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/conduit/Conduit.sol#L130

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/CriteriaResolution.sol#L56

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/CriteriaResolution.sol#L166

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/CriteriaResolution.sol#L184

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/CriteriaResolution.sol#L199

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L181

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L373

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L473

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L498

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L621

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L754

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderFulfiller.sol#L217

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderFulfiller.sol#L306

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderFulfiller.sol#L471

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderValidator.sol#L272

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceCriteriaResolution.sol#L55

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceCriteriaResolution.sol#L157

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceCriteriaResolution.sol#L170

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceCriteriaResolution.sol#L183

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceCriteriaResolution.sol#L221

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceCriteriaResolution.sol#L330

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceExecutor.sol#L382

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceFulfillmentApplier.sol#L170

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceGettersAndDerivers.sol#L111

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L189

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L360

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L467

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L490

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L534

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L582

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L749

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderFulfiller.sol#L345

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderValidator.sol#L265

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderValidator.sol#L329

Example:

        for (uint256 i = 0; i < totalStandardTransfers; ) {

Change uint256 i = 0; to uint256 i;

totalFilteredExecutions is initialized to zero in all four lines below:

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L470

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L751

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L464

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L746

            uint256 totalFilteredExecutions = 0;

Change to uint256 totalFilteredExecutions;

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceBasicOrderFulfiller.sol#L642

                uint256 recipientCount = 0;

Change to 'uint256 recipientCount;'

https://github.com/code-423n4/2022-05-opensea-seaport/blob/7c082637d9273deb42e551c74a578151cefd8448/reference/lib/ReferenceFulfillmentApplier.sol#L167

        uint256 nextComponentIndex = 0;

Change to uint256 nextComponentIndex;

Issue: Use ++i instead of i++ in for loops and do not initialize i to zero

Explanation: Using i++ is more costly than ++i. Initialization of uint variables to their default value of zero is unnecessary and also costs gas

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/conduit/ReferenceConduit.sol#L48

        for (uint256 i = 0; i < totalStandardTransfers; i++) {

Recommendation:

        for (uint256 i; i < totalStandardTransfers; ++i) {

Similarly for the three for loops referenced below:

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/conduit/ReferenceConduit.sol#L69

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/conduit/ReferenceConduit.sol#L91

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/conduit/ReferenceConduit.sol#L102

Issue: Array length should not be looked up in every iteration of a for loop

Explanation: Calculating the array length costs gas

Recommendation: Read the length of the array from memory before executing the loop. In addition, do not initialize i (or j) to zero (its default value)

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L247

                for (uint256 j = 0; j < offer.length; ++j) {

Recommendation:

        uint256 totalOfferLength = offer.length; 
        for (uint256 j; j < totalOfferLength; ++j) {

Similarly for the 14 for loops referenced below:

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L291

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/contracts/lib/OrderCombiner.sol#L598

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceBasicOrderFulfiller.sol#L832

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceBasicOrderFulfiller.sol#L903

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceCriteriaResolution.sol#L378

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceGettersAndDerivers.sol#L104

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L253

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L300

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L603

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderCombiner.sol#L621

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderFulfiller.sol#L188

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderFulfiller.sol#L245

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderFulfiller.sol#L374

https://github.com/code-423n4/2022-05-opensea-seaport/blob/4140473b1f85d0df602548ad260b1739ddd734a5/reference/lib/ReferenceOrderFulfiller.sol#L401