ENS Versus contest details

• Total Prize Pool: $36,500 USDC
  • HM awards: $21,000 USDC
  • QA report awards: $0 USDC
  • Gas report awards: $0 USDC
  • Judge + presort awards: $6,000 USDC
  • Scout awards: $500 USDC
  • Mitigation review contest: $9,000 USDC
• Join C4 Discord to register
• Submit findings using the C4 form
• Read our guidelines for more details
• Starts November 22, 2022 20:00 UTC
• Ends November 28, 2022 20:00 UTC

C4udit / Publicly Known Issues

The C4audit output for the contest can be found here.

Note for C4 wardens: Anything included in the C4udit output is considered a publicly known issue and is ineligible for awards.

About ENS

ENS is a decentralised naming service built on top of Ethereum, and designed to resolve a wide array of resources including blockchain addresses, decentralised content, and user profile information.

Developer documentation can be found here.

Information on existing ENS deployments can be found here.

Developer guide

Setup

git clone https://github.com/code-423n4/2022-11-ens
cd 2022-11-ens
yarn

Running Tests

yarn test

Contracts in scope

Note: Not all contracts in this repository are in-scope for this audit! We have included contracts from the original ens-contracts repo that are dependencies of in-scope contracts here for the convenience of auditors. Only the contracts listed below are in-scope.

This audit is a second audit intended to cover changes made to the Name Wrapper contracts subsequent to the July C4 public audit.

contracts/wrapper

BytesUtils.sol

SLOC: 40

Contains assorted utility functions for manipulating byte strings.

ERC1155Fuse.sol

SLOC: 285

An implementation of ERC1155 that only supports 1 token per token type, with the owner, fuse/flag information, and an expiration time all packed into a single storage slot for gas-efficiency. Should conform to ERC1155, with the addition of ownerOf.

Dependencies:

• @openzeppelin/contracts/utils/introspection/ERC165.sol
• @openzeppelin/contracts/token/ERC1155/IERC1155Receiver.sol
• @openzeppelin/contracts/token/ERC1155/IERC1155.sol
• @openzeppelin/contracts/token/ERC1155/extensions/IERC1155MetadataURI.sol
• @openzeppelin/contracts/utils/Address.sol

NameWrapper.sol

SLOC: 701

A contract that wraps ENS names, providing additional functionality:

• Makes all names at any level valid ERC1155 NFTs.
• Stores name preimages (plaintext names) onchain in an efficient format so they can be processed if needed.
• Allows name owners to permanently or temporarily revoke control over certain aspects of the name, to enable trustless use of ENS names.
• Acts as a controller for the .eth registrar, so that names can be registered and wrapped in a single operation.
• Implements ERC721 receiver functionality, so .eth 2LDs can be wrapped in a single transfer operation.

The primary reason for this wrapper is the 'fuse' functionality for revoking permissions over names; this is intended to support applications such as trustless subdomain issuance, and trustless name resolution.

For detailed documentation of the wrapper and its expected behaviour, see its dedicated README.

Dependencies:

• ERC1155Fuse.sol
• Controllable.sol
• BytesUtil.sol
• ../registry/ENS.sol
• ../ethregistrar/IBaseRegistrar.sol
• @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol
• @openzeppelin/contracts/access/Ownable.sol

INameWrapper.sol

SLOC: 113

Public interface for NameWrapper.sol.

Controllable.sol

SLOC: 17

Mixin for a contract that can have controllers - other accounts that have access to privileged functions.

IMetadataService.sol

SLOC: 4

Interface for a metadata service - a contract that returns token metadata for a wrapped token.

INameWrapperUpgrade.sol

SLOC: 19

Interface for an upgrade target for the name wrapper - a new version of the wrapper.