Raisebox Faucet

Description

Contract Reference: RaiseBoxFaucet.sol

The RaiseBoxFaucet contract contains several code standard and gas optimization issues that do not impact security or functionality but affect code clarity and deployment/runtime gas costs. These issues, identified by Slither, are related to suboptimal use of function visibility and state variable attributes:

1. Public Functions Not Used Internally:

   • Eleven public functions are not called internally within the contract and could be marked external to optimize gas usage and clarify their intended use:

     • mintFaucetTokens(address, uint256) (line 110)

     • burnFaucetTokens(uint256) (line 128)

     • adjustDailyClaimLimit(uint256, bool) (line 143)

     • claimFaucetTokens() (line 162)

     • getBalance(address) (line 276)

     • getClaimer() (line 280)

     • getHasClaimedEth(address) (line 286)

     • getUserLastClaimTime(address) (line 292)

     • getFaucetTotalSupply() (line 297)

     • getContractSepEthBalance() (line 302)

     • getOwner() (line 307)

   • Code Example (for mintFaucetTokens):

     function mintFaucetTokens(address to, uint256 amount) public onlyOwner {

2. State Variable Could Be Constant:

   • The state variable blockTime (line 42) is assigned block.timestamp at deployment but never updated, making it a candidate for the constant keyword to reduce gas costs.

   • Code:

     uint256 public blockTime = block.timestamp;

3. State Variables Could Be Immutable:

   • Three state variables are set only in the constructor and never modified afterward, making them suitable for the immutable keyword to save gas:

     • faucetDrip (line 22)

     • sepEthAmountToDrip (line 34)

     • dailySepEthCap (line 40)

   • Code Example (for faucetDrip):

     uint256 public faucetDrip;

Slither References:

• Public Function Not Used Internally

• State Variable Could Be Constant

• State Variable Could Be Immutable

Severity

Informational
{ Impact — Negligible, Likelihood — N/A }

• Impact: Negligible, as these issues do not affect contract functionality or security. They slightly increase deployment and runtime gas costs and may reduce code clarity.

• Likelihood: N/A, as these are static code quality and optimization issues, not exploitable vulnerabilities.

Risk

• Likelihood of Issue: N/A. These are static code issues present at deployment, not runtime vulnerabilities.

• Potential Consequences:

  • Gas Costs: Public functions not marked external incur minor gas overhead (e.g., ~10–20 gas per external call). Non-constant/non-immutable state variables increase deployment gas costs (~20,000 gas per storage slot) and runtime read costs (negligible).

  • Code Clarity: Public visibility on functions not used internally may mislead developers about their purpose. Non-constant/non-immutable variables suggest mutability, reducing code readability.

  • Operational Impact: No runtime impact in a testnet faucet, but suboptimal code may hinder maintenance or audits.

• Contextual Factors: In a Sepolia testnet faucet, where gas costs and asset value are minimal, these issues are minor and primarily affect code maintainability and developer experience.

Impact

• Gas Costs: Public functions not marked external add slight gas overhead for external calls. Non-constant (blockTime) and non-immutable (faucetDrip, sepEthAmountToDrip, dailySepEthCap) variables increase deployment gas costs (e.g., ~20,000 gas per variable) and minor runtime read costs.

• Code Clarity: Unnecessary public visibility and mutable state variables may confuse developers or auditors, suggesting incorrect usage patterns.

• Testnet Context: In a Sepolia faucet, these issues do not affect user experience or security, as assets have no real value, but they reflect suboptimal code practices.

• Limited Scope: No security or functional impact; purely code standard and optimization concerns.

Tools Used

• Manual Review.

Recommended Mitigation

1. Mark Public Functions as External:

   • Change the visibility of the eleven listed functions from public to external to optimize gas usage and clarify they are not used internally.

   • Example Fix (for mintFaucetTokens):

     // Change from

     function mintFaucetTokens(address to, uint256 amount) public onlyOwner {

     // To

     function mintFaucetTokens(address to, uint256 amount) external onlyOwner {

   • Apply to all listed functions: burnFaucetTokens, adjustDailyClaimLimit, claimFaucetTokens, getBalance, getClaimer, getHasClaimedEth, getUserLastClaimTime, getFaucetTotalSupply, getContractSepEthBalance, getOwner.

2. Make blockTime Constant or Remove:

   • If blockTime is used only for initialization, declare it constant:

     // Change from

     uint256 public blockTime = block.timestamp;

     // To

     uint256 public constant blockTime = 0; // Set to deployment timestamp

   • If blockTime is unused, remove it entirely to save storage:

     // Remove

     uint256 public blockTime = block.timestamp;

3. Make State Variables Immutable:

   • Declare faucetDrip, sepEthAmountToDrip, and dailySepEthCap as immutable since they are set only in the constructor:

     // Change from

     uint256 public faucetDrip;

     uint256 public sepEthAmountToDrip;

     uint256 public dailySepEthCap;

     // To

     uint256 public immutable faucetDrip;

     uint256 public immutable sepEthAmountToDrip;

     uint256 public immutable dailySepEthCap;

   • Ensure these variables are initialized in the constructor:

     constructor() ERC20("RaiseBox", "RBX") Ownable(msg.sender) {

     faucetDrip = 100 * 10**18; // Example value

     sepEthAmountToDrip = 0.01 ether; // Example value

     dailySepEthCap = 1 ether; // Example value

     _mint(address(this), 1000000 * 10**18);

     }

4. Considerations:

   • Verify that the listed functions are not called internally by other contract functions or inherited contracts.

   • Confirm blockTime is unused or only used for initialization; if used dynamically, consider a view function (function getBlockTime() public view returns (uint256) { return block.timestamp; }).

   • Ensure faucetDrip, sepEthAmountToDrip, and dailySepEthCap are only set in the constructor by reviewing the full contract code.

   • Compile and test the contract after applying changes to confirm no unintended side effects.

Proof of Concept

1. Public Functions Not Used Internally:

   • Observation: The functions mintFaucetTokens, burnFaucetTokens, adjustDailyClaimLimit, claimFaucetTokens, getBalance, getClaimer, getHasClaimedEth, getUserLastClaimTime, getFaucetTotalSupply, getContractSepEthBalance, and getOwner are marked public but not called internally, as confirmed by code inspection.

   • Impact: Public visibility adds minor gas overhead (~10–20 gas per external call) compared to external.

   • Fix: Changing to external reduces gas costs and clarifies intent.

2. Non-Constant State Variable:

   • Observation: blockTime (line 42) is set to block.timestamp at deployment and never updated, as verified by code review.

   • Impact: Uses a storage slot (~20,000 gas for deployment) instead of a constant, which would be embedded in bytecode.

   • Fix: Declaring constant or removing (if unused) saves gas.

3. Non-Immutable State Variables:

   • Observation: faucetDrip, sepEthAmountToDrip, and dailySepEthCap (lines 22, 34, 40) are set in the constructor and never modified, as confirmed by inspection.

   • Impact: Each variable uses a storage slot (~20,000 gas per variable for deployment) instead of being embedded in bytecode as immutable.

   • Fix: Declaring immutable reduces gas costs.

These issues can be verified by compiling the contract with and without the fixes, observing gas savings (e.g., using forge build to compare deployment costs).