yixxas - Sequence uptime should be checked

[sherlock-admin]

yixxas

medium

Sequence uptime should be checked

Summary

Chainlink recommends that all Optimistic L2 oracles consult the Sequencer Uptime Feed to ensure that the sequencer is live before trusting the data returned by the oracle. This check is missing in getMarkPrice().

Vulnerability Detail

If the Arbitrum Sequencer goes down, oracle data will not be kept up to date, and thus could become stale. However, users are able to continue to interact with the protocol directly through the L1 optimistic rollup contract.

This causes many issues as the price quoted by getMarkPrice() may not neccessarily be correct.

Impact

If the Arbitrum sequencer goes down, the protocol will continue to operate at the previous (stale) price.

Code Snippet

https://github.com/sherlock-audit/2023-04-jojo/blob/main/smart-contract-EVM/contracts/adaptor/chainlinkAdaptor.sol#L43-L56

Tool used

Manual Review

Recommendation

Consider adding the recommended check by chainlink in their docs here.

Duplicate of #101