Liquid Staking

Summary

In the contract that uses the UUPSUpgradeable pattern, there is no reserved storage gap. This omission creates a risk of storage slot collisions when the contract is upgraded, potentially corrupting the contract’s state. The storage layout can change between versions, and without a gap to account for these changes, future upgrades may overwrite existing storage variables, leading to unpredictable behavior and potentially severe financial or operational impacts.

Vulnerability Detail

When using the UUPS (Universal Upgradeable Proxy Standard) pattern for upgradeable contracts, it's crucial to leave a storage gap in the contract's state variables. This ensures that future upgrades that introduce new state variables do not overwrite existing ones.

In this contracts, there is no uint256[50] private __gap; or similar placeholder to reserve storage slots for potential future upgrades. Without this reserved gap, when new variables are added in future versions, they may conflict with current state variables, causing storage slot collisions. This can result in:

• Incorrect values for critical state variables.

• Loss of important data or functionality.

• Unpredictable behavior or contract failures.

Impact

• Data corruption: Future upgrades may overwrite current state variables, leading to data loss or corruption.

• Functional failures: Contracts functionality may break due to misaligned storage, which could trigger unintended consequences in operations like fund management, user balances, or governance decisions.

• Financial loss: If critical variables such as token balances or staking amounts are corrupted, it could lead to significant financial losses for users or the protocol.

Code Snippet

https://github.com/Cyfrin/2024-09-stakelink/blob/f5824f9ad67058b24a2c08494e51ddd7efdbb90b/contracts/linkStaking/OperatorStakingPool.sol#L16
https://github.com/Cyfrin/2024-09-stakelink/blob/f5824f9ad67058b24a2c08494e51ddd7efdbb90b/contracts/linkStaking/FundFlowController.sol#L16
https://github.com/Cyfrin/2024-09-stakelink/blob/f5824f9ad67058b24a2c08494e51ddd7efdbb90b/contracts/core/priorityPool/PriorityPool.sol#L21

Tool used

Manual Review

Recommendation

To prevent storage collisions during future upgrades, add a storage gap in the contracts. This will reserve storage slots that can be safely used in future versions, preventing overwriting of existing state variables.

Recommended Fix:

By adding a gap, it ensure that the contract remains safe for upgrades, protecting state variables from unintended overwrites.