limits and tiered confirmations in ChainPolicy

[0xpatrickdev]

What is the Problem Being Solved?

As an additional layer of security, the protocol should:

• limit advance requests for a single tx over a configurable amount
• limit advance requests for txs in a configurable range of blocks over a configurable amount

Additionally:

• tier number of confirmations based on tx amount
• tier number of confirmation based on cumulative amount in block range

These values will be specified in the ChainPolicy and the logic will be implemented by oracle operator software.

Description of the Design

For MVP:

• limit advance requests for a single tx over a configurable amount
  • add maxAmountPerTx: bigint to ChainPolicy
• limit advance requests for txs in a configurable range of blocks over a configurable amount
  • add maxAmountPerBlockWindow: bigint and blockWindowSize: number to ChainPolicy

Stretch Goal for MVP:

• tier number of confirmations based on tx amount
  • add txThresholds: {maxAmount: bigint; confirmations: number;}[] to ChainPolicy
• tier number of confirmation based on cumulative amount in block range
  • add blockThresholds: {maxAmount: bigint; confirmations: number;}[] to ChainPolicy

Security Considerations

Scaling Considerations

Test Plan

Upgrade Considerations

[0xpatrickdev]

We are holding off on tiered confirmations for now, but have added the following:

type ChainPolicy = {
  ...
  rateLimits: {
    /** do not advance more than this amount for an individual transaction */
    tx: bigint;
    /** do not advance more than this amount per block window */
    blockWindow: bigint;
    /** the number of blocks to consider for `blockWindow` */
    blockWindowSize: number;
  }
};

#10814 is in the merge queue and will close this ticket