add IERC5267, use token name for EIP712 domain

Author: d10r

packages/ethereum-contracts/CHANGELOG.md

@@ -3,6 +3,11 @@ All notable changes to the ethereum-contracts will be documented in this file.
 
 This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [unreleased]
+
+### Added
+- `SuperToken` now implements [EIP-2612](https://eips.ethereum.org/EIPS/eip-2612) (permit extension for EIP-20 signed approvals)
+
 ## [v1.12.1]
 
 ### Added

packages/ethereum-contracts/contracts/interfaces/superfluid/ISuperToken.sol

@@ -4,6 +4,7 @@ pragma solidity >= 0.8.11;
 import { ISuperfluidToken } from "./ISuperfluidToken.sol";
 import { IERC20, IERC20Metadata } from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
 import { IERC20Permit } from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Permit.sol";
+import { IERC5267 } from "@openzeppelin/contracts/interfaces/IERC5267.sol";
 import { IERC777 } from "@openzeppelin/contracts/token/ERC777/IERC777.sol";
 import { IPoolAdminNFT } from "../agreements/gdav1/IPoolAdminNFT.sol";
 import { IPoolMemberNFT } from "../agreements/gdav1/IPoolMemberNFT.sol";
@@ -12,7 +13,7 @@ import { IPoolMemberNFT } from "../agreements/gdav1/IPoolMemberNFT.sol";
  * @title Super token (Superfluid Token + ERC20 + ERC777) interface
  * @author Superfluid
  */
-interface ISuperToken is ISuperfluidToken, IERC20Metadata, IERC777, IERC20Permit {
+interface ISuperToken is ISuperfluidToken, IERC20Metadata, IERC777, IERC20Permit, IERC5267 {
 
     /**************************************************************************
      * Errors

packages/ethereum-contracts/contracts/superfluid/SuperToken.sol

@@ -52,6 +52,10 @@ contract SuperToken is
     // EIP-712 permit typehash
     bytes32 constant private _PERMIT_TYPEHASH =
         keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
+    bytes32 constant private _EIP712_DOMAIN_TYPEHASH =
+        keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");
+
+    string constant private _EIP712_VERSION = "1";
 
     // solhint-disable-next-line var-name-mixedcase
     IConstantOutflowNFT immutable public CONSTANT_OUTFLOW_NFT;
@@ -188,14 +192,14 @@ contract SuperToken is
         UUPSProxiable._updateCodeAddress(newAddress);
     }
 
-    function changeAdmin(address newAdmin) external override onlyAdmin {
+    function changeAdmin(address newAdmin) external virtual override onlyAdmin {
         address oldAdmin = _getAdmin();
         _setAdmin(newAdmin);
 
         emit AdminChanged(oldAdmin, newAdmin);
     }
 
-    function getAdmin() external view override returns (address) {
+    function getAdmin() external view virtual override returns (address) {
         return _getAdmin();
     }
 
@@ -243,7 +247,7 @@ contract SuperToken is
         uint8 v,
         bytes32 r,
         bytes32 s
-    ) public override {
+    ) public virtual override {
         if (block.timestamp > deadline) revert SUPER_TOKEN_PERMIT_EXPIRED_SIGNATURE(deadline);
 
         bytes32 structHash = keccak256(
@@ -278,25 +282,53 @@ contract SuperToken is
 
     /// @dev EIP-712 Domain Separator
     // solhint-disable func-name-mixedcase
-    function DOMAIN_SEPARATOR() public view virtual returns (bytes32) {
+    function DOMAIN_SEPARATOR() public view virtual override returns (bytes32) {
         // TODO: can be optimized: provide immutable parts from constants
         return keccak256(
             abi.encode(
-                // TYPE_HASH
-                keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"), 
-                keccak256("SuperToken"), // name
-                keccak256("1"), // version
+                _EIP712_DOMAIN_TYPEHASH,
+                keccak256(bytes(_name)),
+                keccak256(bytes(_EIP712_VERSION)),
                 block.chainid,
                 address(this)
             )
         );
     }
 
     /// @dev EIP-2612 Nonces
-    function nonces(address owner) public view virtual returns (uint256) {
+    function nonces(address owner) public view virtual override returns (uint256) {
         return _nonces[owner];
     }
 
+    /// @dev EIP-5267: Retrieval of EIP-712 domain
+    function eip712Domain()
+        public
+        view
+        virtual
+        override
+        returns
+        (
+            bytes1 fields,
+            /* commented out to avoid warning of name clash with name() */
+            string memory /*name*/,
+            string memory version,
+            uint256 chainId,
+            address verifyingContract,
+            bytes32 salt,
+            uint256[] memory extensions
+        )
+    {
+        return (
+            hex"0f", // 01111 - field "salt" not present
+            _name,
+            _EIP712_VERSION,
+            block.chainid,
+            address(this), // verifyingContract
+            bytes32(0), // salt
+            new uint256[](0) // extensions
+        );
+    }
+
     /**************************************************************************
      * (private) Token Logics
      *************************************************************************/