Merge pull request #84 from PolymathNetwork/offchain_whitelist

Add off-chain signing ability

CHANGELOG.md

@@ -14,15 +14,15 @@ All notable changes to this project will be documented in this file.
 
 * IModule contract takes the polyToken contract address as the constructor argument to wrapping all the factories with the polyToken contract address.      
 * `takeFee()` new function introduced to extract the POLY token from the factory. It only be called by the owner of the factory.      
-
+* Added ability for issuer to provide a signed piece of data to allow investors to whitelist themselves.
 
 ***
 
 [__0.3.1__](https://www.npmjs.com/package/polymath-core?activeTab=readme) __06-04-18__
 
 ## Added
 * Add `emit` keyword to emit the events.    
-* Two new variable is added at the time of registeration of ticker. `swarmHash` represents the off-chain data storage location on IPFS and `owner` It reperesent the ethereum address of the owner.       
+* Two new variable is added at the time of registration of ticker. `swarmHash` represents the off-chain data storage location on IPFS and `owner` It reperesent the ethereum address of the owner.       
 * `LogRegisterTicker` emits two more variable called `_swarmHash` and `_owner`.   
 * Two events are added in `GeneralPermissionManager` contract to facilitate the notifications for the UI end.
           __`LogChangePermission`__ :Emit when permissions to a delegate get changed.    

contracts/Migrations.sol

@@ -4,15 +4,15 @@ pragma solidity ^0.4.23;
 contract Migrations {
 
     address public owner;
-  
+
     uint public lastCompletedMigration;
 
     modifier restricted() {
         require(msg.sender == owner);
         _;
     }
 
-    constructor() public {
+    function Migrations() public {
         owner = msg.sender;
     }
 

contracts/interfaces/IModule.sol

@@ -27,29 +27,29 @@ contract IModule {
     modifier withPerm(bytes32 _perm) {
         bool isOwner = msg.sender == ISecurityToken(securityToken).owner();
         bool isFactory = msg.sender == factory;
-        require(isOwner||isFactory||ISecurityToken(securityToken).checkPermission(msg.sender, address(this), _perm));
+        require(isOwner||isFactory||ISecurityToken(securityToken).checkPermission(msg.sender, address(this), _perm), "Permission check failed");
         _;
     }
 
     modifier onlyOwner {
-        require(msg.sender == ISecurityToken(securityToken).owner());
+        require(msg.sender == ISecurityToken(securityToken).owner(), "Sender is not owner");
         _;
     }
 
     modifier onlyFactory {
-        require(msg.sender == factory);
+        require(msg.sender == factory, "Sender is not factory");
         _;
     }
 
     modifier onlyFactoryOwner {
-        require(msg.sender == IModuleFactory(factory).owner());
+        require(msg.sender == IModuleFactory(factory).owner(), "Sender is not factory owner");
         _;
     }
 
     function getPermissions() public view returns(bytes32[]);
 
     function takeFee(uint256 _amount) public withPerm(FEE_ADMIN) returns(bool) {
-        require(polyToken.transferFrom(address(this), IModuleFactory(factory).owner(), _amount));
+        require(polyToken.transferFrom(address(this), IModuleFactory(factory).owner(), _amount), "Unable to take fee");
         return true;
     }
 }

contracts/modules/PermissionManager/GeneralPermissionManager.sol

@@ -80,7 +80,7 @@ contract GeneralPermissionManager is IPermissionManager {
     withPerm(CHANGE_PERMISSION)
     returns(bool)
     {
-        require(delegateDetails[_delegate] != bytes32(0));
+        require(delegateDetails[_delegate] != bytes32(0), "Delegate details not set");
         perms[_module][_delegate][_perm] = _valid;
         emit LogChangePermission(_delegate, _module, _perm, _valid, now);
         return true;

contracts/modules/TransferManager/GeneralTransferManager.sol

@@ -18,6 +18,9 @@ contract GeneralTransferManager is ITransferManager {
     //Address from which issuances come
     address public issuanceAddress = address(0);
 
+    //Address which can sign whitelist changes
+    address public signingAddress = address(0);
+
     bytes32 public constant WHITELIST = "WHITELIST";
     bytes32 public constant FLAGS = "FLAGS";
 
@@ -42,6 +45,7 @@ contract GeneralTransferManager is ITransferManager {
     event LogAllowAllTransfers(bool _allowAllTransfers);
     event LogAllowAllWhitelistTransfers(bool _allowAllWhitelistTransfers);
     event LogAllowAllWhitelistIssuances(bool _allowAllWhitelistIssuances);
+    event LogChangeSigningAddress(address _signingAddress);
 
     event LogModifyWhitelist(
         address _investor,
@@ -66,6 +70,11 @@ contract GeneralTransferManager is ITransferManager {
         emit LogChangeIssuanceAddress(_issuanceAddress);
     }
 
+    function changeSigningAddress(address _signingAddress) public withPerm(FLAGS) {
+        signingAddress = _signingAddress;
+        emit LogChangeSigningAddress(_signingAddress);
+    }
+
     function changeAllowAllTransfers(bool _allowAllTransfers) public withPerm(FLAGS) {
         allowAllTransfers = _allowAllTransfers;
         emit LogAllowAllTransfers(_allowAllTransfers);
@@ -123,13 +132,41 @@ contract GeneralTransferManager is ITransferManager {
         uint256[] _fromTimes,
         uint256[] _toTimes
     ) public withPerm(WHITELIST) {
-        require(_investors.length == _fromTimes.length);
-        require(_fromTimes.length == _toTimes.length);
+        require(_investors.length == _fromTimes.length, "Mismatched input lengths");
+        require(_fromTimes.length == _toTimes.length, "Mismatched input lengths");
         for (uint256 i = 0; i < _investors.length; i++) {
             modifyWhitelist(_investors[i], _fromTimes[i], _toTimes[i]);
         }
     }
 
+    /**
+    * @dev adds or removes addresses from the whitelist - can be called by anyone with a valid signature
+    * @param _investor is the address to whitelist
+    * @param _fromTime is the moment when the sale lockup period ends and the investor can freely sell his tokens
+    * @param _toTime is the moment when the purchase lockup period ends and the investor can freely purchase tokens from others
+    * @param _validFrom is the time that this signature is valid from
+    * @param _validTo is the time that this signature is valid until
+    * @param _v issuer signature
+    * @param _r issuer signature
+    * @param _s issuer signature
+    */
+    function modifyWhitelistSigned(address _investor, uint256 _fromTime, uint256 _toTime, uint256 _validFrom, uint256 _validTo, uint8 _v, bytes32 _r, bytes32 _s) public {
+        require(_validFrom <= now, "ValidFrom is too early");
+        require(_validTo >= now, "ValidTo is too late");
+        bytes32 hash = keccak256(this, _investor, _fromTime, _toTime, _validFrom, _validTo);
+        checkSig(hash, _v, _r, _s);
+        //Passing a _time == 0 into this function, is equivalent to removing the _investor from the whitelist
+        whitelist[_investor] = TimeRestriction(_fromTime, _toTime);
+        emit LogModifyWhitelist(_investor, now, msg.sender, _fromTime, _toTime);
+    }
+
+    function checkSig(bytes32 _hash, uint8 _v, bytes32 _r, bytes32 _s) internal view {
+        //Check that the signature is valid
+        //sig should be signing - _investor, _fromTime & _toTime and be signed by the issuer address
+        address signer = ecrecover(keccak256("\x19Ethereum Signed Message:\n32", _hash), _v, _r, _s);
+        require(signer == ISecurityToken(securityToken).owner() || signer == signingAddress, "Incorrect signer");
+    }
+
     function getPermissions() public view returns(bytes32[]) {
         bytes32[] memory allPermissions = new bytes32[](2);
         allPermissions[0] = WHITELIST;

contracts/tokens/SecurityToken.sol

@@ -64,9 +64,9 @@ contract SecurityToken is ISecurityToken, StandardToken, DetailedERC20 {
             isModuleType = isModuleType || (modules[_moduleType][i].moduleAddress == msg.sender);
         }
         if (_fallback && !isModuleType) {
-            require(msg.sender == owner);
+            require(msg.sender == owner, "Sender is not owner");
         } else {
-            require(isModuleType);
+            require(isModuleType, "Sender is not correct module type");
         }
         _;
     }
@@ -200,9 +200,9 @@ contract SecurityToken is ISecurityToken, StandardToken, DetailedERC20 {
     * @dev allows owner to approve more POLY to one of the modules
     */
     function changeModuleBudget(uint8 _moduleType, uint8 _moduleIndex, uint256 _budget) public onlyOwner {
-        require(_moduleType != 0);
-        require(_moduleIndex < modules[_moduleType].length);
-        require(polyToken.approve(modules[_moduleType][_moduleIndex].moduleAddress, _budget));
+        require(_moduleType != 0, "Module type cannot be zero");
+        require(_moduleIndex < modules[_moduleType].length, "Incorrrect module index");
+        require(polyToken.approve(modules[_moduleType][_moduleIndex].moduleAddress, _budget), "Insufficient balance to approve");
         emit LogModuleBudgetChanged(_moduleType, modules[_moduleType][_moduleIndex].moduleAddress, _budget);
     }
 

package.json

@@ -51,6 +51,7 @@
     "babel-preset-stage-3": "6.24.1",
     "babel-register": "6.26.0",
     "bignumber.js": "^6.0.0",
+    "ethers": "^3.0.15",
     "readline-sync": "^1.4.9",
     "truffle-contract": "^3.0.4",
     "truffle-hdwallet-provider-privkey": "^0.1.0",
@@ -68,7 +69,7 @@
     "ganache-cli": "^6.1.0",
     "sol-merger": "^0.1.2",
     "solium": "^1.1.6",
-    "truffle": "^4.1.5",
+    "truffle": "^4.1.7",
     "truffle-wallet-provider": "0.0.5"
   }
 }