godsflaw / mkr-mcd-spec

KMCD - MKR Multi-Collateral Dai (MCD) KSpecification

UNDER CONSTRUCTION

Useful Links

• Initial RFP for security audits: https://www.notion.so/MCD-Security-Audit-ac578a595ac74958877106c77f1b85b0
• K-DSS bytecode verification: https://dapp.ci/k-dss/
• DSS solidity sources: https://github.com/makerdao/dss
• Useful invariants: https://hackmd.io/lWCjLs9NSiORaEzaWRJdsQ (maybe work take is out of date)
• MCD Documentation: https://www.notion.so/MCD-Documentation-WIP-2ec33e10c4704243b1c473ec44f42576
• MCD Wiki: https://github.com/makerdao/dss/wiki/Actions

Structure

The semantics is broken into several sub-modules.

• kmcd-driver - common functionality in all modules.

• kmcd - union all sub-modules.

• cdp-core - core accounting system for MCD.

• collateral - collateral linking.

• dai - ERC20 fungible collateral version of Dai.

• rates - rate adjustments and price feeds

• stabilize - forcible stabilization of risky CDPs.

Potential Properties

• After executing method X of contract C, the suffix of the log will contain these events ...
• Every time a ward changes, a log event should be emmitted which says so (and the log event should have the correct data). Will only apply to methods which have note modifier, but perhaps should be always.
• Fundamental equation of Dai (invariant over CDPs + dai).
• What happens if the "maintenance" functions like drip are not called for too long of a timeframe? Drip is called by jug.sol and pot.sol, and if not called frequently enough, system could act funny.

One of the architecture decisions made was to make *Like interfaces for actually accessing functions/data of the underlying implementations. For example, Cat has Urn defined just to have access to the getters/setters from other contracts.

For inverting storage of vat so that we have some implicit account (msg.sender), we should inspect frob as a test-case, because it access wish on three different passed in addresses.

Order to Model

• vat.sol
• lib.sol

Second layer:

• jug.sol
• pot.sol
• spot.sol

Collateral:

• dai.sol
• join.sol

Auctions:

• vow.sol
• cat.sol
• flop.sol
• flip.sol
• flap.sol

Global:

• end.sol