Crucial setter functions lack checks for valid inputs

[code423n4]

Lines of code

https://github.com/code-423n4/2022-05-aura/blob/4989a2077546a5394e3650bf3c224669a0f7e690/convex-platform/contracts/contracts/Booster.sol#L128-L153
https://github.com/code-423n4/2022-05-aura/blob/4989a2077546a5394e3650bf3c224669a0f7e690/convex-platform/contracts/contracts/VoterProxy.sol#L83-L87

Vulnerability details

Impact

Several important setter functions lack checks to determine the parameters' validity. The malicious or accidental use of incorrect parameters may lead to unwanted results. The vulnerabilities have been split into two categories depending on their effects.

-Category 1: Incorrect inputs can lead to frozen or stolen funds
-Category 2: Incorrect inputs can lead to DoS of major protocol functionality

Proof of Concept

Category 1:

-Booster.setOwner() has no zero address check. If it is accidentally set to address(0), updating voting delegate will not be possible. Secondly the shutdownSystem() function will be be inaccessible in case of an attack. Lastly, withdrawing (through _withdraw()) will not be possible and funds will be stuck.

Category 2:

-Booster.setFeeManager has no zero address check. If address is accidentally set to zero fees (lockIncentive, stakeIncentive, earmarkIncentive, platformFee) will not be able to be updated.
-Booster.setPoolManager has no zero address check. If address is accidentally set to zero it will not be possible to add or shutdown pools. Could be dangerous in case a pool finds itself under attack.
-Booster.setVoteDelegate has no zero address check. If address is accidentally set to zero it will not be possible to cast votes on VoterProxy.sol
Booster.setTreasury has no zero address check. If it is accidentally set to zero no crv will be sent to it and will accumulate in Booster.sol.
VoterProxy.setOwner has no zero address check. If it is accidentally set to zero it will not be possible to use setRewardDeposit, setSystemConfig, setOperator and other functions. This might lead to having to redeploy the contract.

Tools Used

Manual review.

Recommended Mitigation Steps

Add checks to validate that input addresses for crucial setter functions are not address(0).

[0xMaharishi]

Checking for address(0) is not a big deal but 2 way handshakes here would be optimal

[0xMaharishi]

code-423n4/2022-05-aura#6

[dmvt]

Per #364 (comment) I have decided to downgrade this to QA.

[dmvt]

Grouping this with the warden’s QA report, #246