Audit Plan

[lucasmt]

Supernode Code Review

• Check that the Supernode implementation maintains the invariants on each of the main execution paths (including when starting from the initial, empty state):
  • Cross-validation succeeds.
  • Cross-validation fails.
  • Waiting for L2s to sync.
  • L1 reorg.
• Collect all execution paths that are not covered by the above. Ensure that they are exceptional cases that, under our assumptions about L1/L2 behavior, either shouldn't happen or should be recovered from in time.
• Check that when cross-validation returns with an error, any intermediate state changes are cleaned up.
• Review implementation of ChainContainer (including VirtualNode and EngineController) and check for any potential issues when pulling L2 data.
• Review implementation of L2 rewind procedure and check that it correctly resets the chains to the previous timestamp.
• Review implementation of the DenyList and that it correctly reports invalidated blocks when queried by the VirtualNode.
• Check correctness of Executing Message validity check, including same-timestamp validation (cycle check).
• Check liveness: is there a scenario where the Supernode stops making progress?
• Consider what happens when the L1 or the L2s reorg in the middle of a round of cross-validation. Identify each point where the L1/L2s are queried and might be inconsistent. Make sure there are proper consistency checks to maintain the invariants, or else that there is a mechanism for the protocol to recover from inconsistencies.
• Check for low-level issues:
  • Arithmetic overflow/underflow.
  • Out-of-bounds array access.
  • Race conditions/other concurrency issues.

Interop-Filter Code Review

• Check that the cross-unsafe validation mechanism works correctly and is consistent with the cross-safe validation implemented in the Supernode (but note that unlike the Supernode, the Interop-Filter does not perform same-timestamp cycle detection).
  • The Interop Filter must return FALSE (invalid) for invalid transactions. (High/Medium)
  • The Interop Filter must return TRUE (valid) for valid transactions. (Low)
• Check that failsafe mode operates correctly.
  • When failsafe mode is enabled, the Interop Filter must return FALSE for all requests. (Low)
• Verify LogsDBChainIngester.
  • LogsDBChainIngester correctly pulls information from the L2 chain.
  • LogsDBChainIngester correctly updates and queries the logs database.
• Verify failure recovery behavior.