FMA: SuperchainWETH

[tynes]

The following FMA exists for SuperchainWETH: https://github.com/ethereum-optimism/design-docs/blob/f3aa2db64b1676b5e58ae602acf2ebdba34b617c/security/fma-superchainweth.md

This ticket is complete when the FMA is considered finalized.

[tynes]

It is currently in implementing actions phase. Given the recent work towards renaming SuperchainWETH to SuperchainETHBridge here, we will want to reevaluate this FMA. At first glance, it appears as if the existing failure modes will be the same and do not need to be modified. cc @tremarkley

Regarding the monitoring action item, we need to decide if a generic "double check all executing messages are valid" sort of monitoring is enough, or if we need to have something specific to check eth balances. I lean towards thinking that just having monitoring around all valid executing messages should be good enough, this assumes that there is no way to unlock the eth from the ETHLockbox without an executing message being created. cc @mds1 @smartcontracts

[agusduha]

Review:

• FMA1 and FMA2 still relevant for the SuperchainETHBridge changes
• Monitoring over the Msg Passing FMA seems enough to cover these cases

[tremarkley]

Did a review and the existing failure modes should still hold. Created this PR to update the FMA to reference SuperchainETHBridge instead of SuperchainWETH cc @agusduha @tynes

[agusduha]

Finalizing PR: #250

[mds1]

Reassigned this one to @smartcontracts since he reviewed the original FMA

[op-aaron]

Approved and merged so closing issue.