Weather Witness
First Flight #40
Beginner FriendlyFoundrySolidityNFT
100 EXP
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Submission Details
Impact: low
Likelihood: medium
Invalid

## WeatherNft.sol ## [ _registerKeeper check ]

hawks

Root + Impact

Description

The requestMintWeatherNFT function does not check whether a keeper is already registered before attempting to register them again. If a user calls the function with _registerKeeper = true, and the address has already been registered as a keeper previously, it could result in:

  • duplicate registrations

  • LINK token transfer waste

  • potential overwrites of keeper-related logic or data

This missing check undermines the assumption that each keeper is unique and registered only once.

​
@> if (_registerKeeper) {
IERC20(s_link).safeTransferFrom(
msg.sender,
address(this),
_initLinkDeposit
);
}

Risk

Likelihood:

  • A user may repeatedly call requestMintWeatherNFT with _registerKeeper = true, either by accident or maliciously.

  • The contract currently has no internal check preventing this, so it allows LINK transfers and stores duplicate keeper intents.

Impact:

  • Keeper registry corruption: if additional logic is built around registeredKeepers, unexpected overwrites may occur.

  • Wasted LINK: repeated safeTransferFrom calls drain the user's LINK balance.

  • Inconsistent behavior: contract functions relying on single-registration assumptions may malfunction.

Proof of Concept

​

Recommended Mitigation

Add a mapping(address => bool) to track registered keepers and a helper function isKeeperRegistered(address) to check the registration status. Then, update the requestMintWeatherNFT function to revert if the caller is already registered before proceeding with the keeper registration logic.

if (_registerKeeper) {
- IERC20(s_link).safeTransferFrom(
- msg.sender,
- address(this),
- _initLinkDeposit
- );
- }
​
​
+ mapping(address => bool) public registeredKeepers;
​
+ function isKeeperRegistered(address keeper) public view returns (bool) {
+ return registeredKeepers[keeper];
+ }
​
+ if (_registerKeeper) {
+ require(!isKeeperRegistered(msg.sender), "Keeper already registered");
+ IERC20(s_link).safeTransferFrom(
+ msg.sender,
+ address(this),
+ _initLinkDeposit
+ );
+ registeredKeepers[msg.sender] = true;
+ }
Updates

Appeal created

bube Lead Judge 5 months ago
Submission Judgement Published
Invalidated
Reason: Incorrect statement

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