Change function visibility from public to external

[code423n4]

Handle

0xRajeev

Vulnerability details

Impact

Various functions across contracts are never called from within contracts but yet declared public. Their visibility can be made external to save gas.

As described in https://mudit.blog/solidity-gas-optimization-tips/: “For all the public functions, the input parameters are copied to memory automatically, and it costs gas. If your function is only called externally, then you should explicitly mark it as external. External function’s parameters are not copied into memory but are read from calldata directly. This small optimization in your solidity code can save you a lot of gas when the function input parameters are huge.”

Proof of Concept

__NFTXVault_init: https://github.com/code-423n4/2021-05-nftx/blob/f6d793c136d110774de259d9f3b25d003c4f8098/nftx-protocol-v2/contracts/solidity/NFTXVaultUpgradeable.sol#L100-L106

__NFTXVaultFactory_init: https://github.com/code-423n4/2021-05-nftx/blob/f6d793c136d110774de259d9f3b25d003c4f8098/nftx-protocol-v2/contracts/solidity/NFTXVaultFactoryUpgradeable.sol#L33

createVault: https://github.com/code-423n4/2021-05-nftx/blob/f6d793c136d110774de259d9f3b25d003c4f8098/nftx-protocol-v2/contracts/solidity/NFTXVaultFactoryUpgradeable.sol#L41-L47

setFeeReceiver: https://github.com/code-423n4/2021-05-nftx/blob/f6d793c136d110774de259d9f3b25d003c4f8098/nftx-protocol-v2/contracts/solidity/NFTXVaultFactoryUpgradeable.sol#L62

addModule: https://github.com/code-423n4/2021-05-nftx/blob/f6d793c136d110774de259d9f3b25d003c4f8098/nftx-protocol-v2/contracts/solidity/NFTXEligiblityManager.sol#L20

updateModule: https://github.com/code-423n4/2021-05-nftx/blob/f6d793c136d110774de259d9f3b25d003c4f8098/nftx-protocol-v2/contracts/solidity/NFTXEligiblityManager.sol#L25

FeeDistributor__init: https://github.com/code-423n4/2021-05-nftx/blob/f6d793c136d110774de259d9f3b25d003c4f8098/nftx-protocol-v2/contracts/solidity/NFTXFeeDistributor.sol#L35

setEligibilityPreferences: https://github.com/code-423n4/2021-05-nftx/blob/f6d793c136d110774de259d9f3b25d003c4f8098/nftx-protocol-v2/contracts/solidity/eligibility/NFTXUniqueEligibility.sol#L85-L86

setUniqueEligibilities: https://github.com/code-423n4/2021-05-nftx/blob/f6d793c136d110774de259d9f3b25d003c4f8098/nftx-protocol-v2/contracts/solidity/eligibility/NFTXUniqueEligibility.sol#L93-L94

setUniqueEligibilities: https://github.com/code-423n4/2021-05-nftx/blob/f6d793c136d110774de259d9f3b25d003c4f8098/nftx-protocol-v2/contracts/solidity/eligibility/NFTXMintRequestEligibility.sol#L218-L219

Tools Used

Manual Analysis

Recommended Mitigation Steps

Change function visibility from public to external