Submitted by Ruhum
According to the LayerZero docs, the default behavior is that when a transaction on the destination application fails, the channel between the src and dst app is blocked. Before any new transactions can be executed, the failed transaction has to be retried until it succeeds.
See https://layerzero.gitbook.io/docs/faq/messaging-properties#message-ordering & https://layerzero.gitbook.io/docs/guides/advanced/nonblockinglzapp
So an attacker is able to initiate a transaction they know will fail to block the channel between FTM and Optimism. The RedemptionSender & Receiver wont be usable anymore.
The RedemptionReceiver contract doesnt implement the non-blocking approach as seen here:
https://github.com/code-423n4/2022-05-velodrome/blob/main/contracts/contracts/redeem/RedemptionReceiver.sol#L72-L105
An example implementation of the non-blocking approach by LayerZero:
https://github.com/LayerZero-Labs/solidity-examples/blob/main/contracts/lzApp/NonblockingLzApp.sol
Use the non-blocking approach as described here.
pooltypes (Velodrome) disagreed with severity
Alex the Entreprenerd (judge) commented:
Alex the Entreprenerd (judge) commented:
Alex the Entreprenerd (judge) increased severity to High and commented:
ethzoomer (Velodrome) commented:
Alex the Entreprenerd (judge) commented:
