Lack of sanity check in ProtocolDAO.upgradeExistingContract may cause the guardian to delete a contract instead of upgrading it

[code423n4]

Lines of code

https://github.com/code-423n4/2022-12-gogopool/blob/aec9928d8bdce8a5a4efe45f54c39d4fc7313731/contracts/contract/ProtocolDAO.sol#L209-L217
https://github.com/code-423n4/2022-12-gogopool/blob/aec9928d8bdce8a5a4efe45f54c39d4fc7313731/contracts/contract/ProtocolDAO.sol#L198-L203
https://github.com/code-423n4/2022-12-gogopool/blob/aec9928d8bdce8a5a4efe45f54c39d4fc7313731/contracts/contract/ProtocolDAO.sol#L190-L194

Vulnerability details

Impact

Guardian may accidentally delete a contract. Might waste gas and also cause confusion to the users and the guardian himself.

Proof of Concept

When the protocol decides to upgrade its contract, it calls upgradeExistingContract in ProtocolDAO.sol. The upgradeExistingContract calls registerContract and registers a new address and name, then unregisterContract to delete the old contract address and name.

function upgradeExistingContract(
	address newAddr,
	string memory newName,
	address existingAddr
) external onlyGuardian {
	registerContract(newAddr, newName);
	unregisterContract(existingAddr);
}

If the guardian accidentally uses the same new address for both new and existing addresses, then there will be nothing to upgrade.

https://github.com/code-423n4/2022-12-gogopool/blob/aec9928d8bdce8a5a4efe45f54c39d4fc7313731/contracts/contract/ProtocolDAO.sol#L209-L217
https://github.com/code-423n4/2022-12-gogopool/blob/aec9928d8bdce8a5a4efe45f54c39d4fc7313731/contracts/contract/ProtocolDAO.sol#L198-L203
https://github.com/code-423n4/2022-12-gogopool/blob/aec9928d8bdce8a5a4efe45f54c39d4fc7313731/contracts/contract/ProtocolDAO.sol#L190-L194

Recommended Mitigation Steps

Make sure newAddr is not equal to existing Addr and newAddr is not the same as current Addr.

[c4-judge]

GalloDaSballo marked the issue as duplicate of #742

[c4-judge]

GalloDaSballo marked the issue as satisfactory