Security enhancement v1.6

contracts/LoopringProtocolImpl.sol

@@ -530,7 +530,6 @@ contract LoopringProtocolImpl is LoopringProtocol {
         private
         view
     {
-
         uint ringSize = ctx.ringSize;
         Order[] memory orders = ctx.orders;
 
@@ -645,7 +644,7 @@ contract LoopringProtocolImpl is LoopringProtocol {
                 // If the order is selling LRC, we need to calculate how much LRC
                 // is left that can be used as fee.
                 if (order.tokenS == lrcTokenAddress) {
-                    lrcSpendable -= order.fillAmountS;
+                    lrcSpendable = lrcSpendable.sub(order.fillAmountS);
                 }
 
                 // If the order is buyign LRC, it will has more to pay as fee.
@@ -654,7 +653,7 @@ contract LoopringProtocolImpl is LoopringProtocol {
                     lrcReceiable = nextFillAmountS;
                 }
 
-                uint lrcTotal = lrcSpendable + lrcReceiable;
+                uint lrcTotal = lrcSpendable.add(lrcReceiable);
 
                 // If order doesn't have enough LRC, set margin split to 100%.
                 if (lrcTotal < order.lrcFeeState) {
@@ -673,7 +672,7 @@ contract LoopringProtocolImpl is LoopringProtocol {
                         order.lrcFeeState = 0;
                     } else {
                         order.splitB = lrcReceiable;
-                        order.lrcFeeState -= lrcReceiable;
+                        order.lrcFeeState = order.lrcFeeState.sub(lrcReceiable);
                     }
                 }
             } else {
@@ -719,7 +718,7 @@ contract LoopringProtocolImpl is LoopringProtocol {
                     // be paid LRC reward first, so the orders in the ring does
                     // mater.
                     if (split > 0) {
-                        minerLrcSpendable -= order.lrcFeeState;
+                        minerLrcSpendable = minerLrcSpendable.sub(order.lrcFeeState);
                         order.lrcReward = order.lrcFeeState;
                     }
                 }

contracts/TokenTransferDelegateImpl.sol

@@ -27,6 +27,7 @@ import "./TokenTransferDelegate.sol";
 
 /// @title An Implementation of TokenTransferDelegate.
 /// @author Daniel Wang - <[email protected]>.
+/// @author Kongliang Zhong - <[email protected]>.
 contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
     using MathUint for uint;
 
@@ -40,6 +41,9 @@ contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
         require(_walletSplitPercentage >= 0 && _walletSplitPercentage <= 100);
         walletSplitPercentage = _walletSplitPercentage;
     }
+
+    bool public suspended = false;
+
     struct AddressInfo {
         address previous;
         uint32  index;
@@ -55,6 +59,18 @@ contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
         _;
     }
 
+    modifier notSuspended()
+    {
+        require(!suspended);
+        _;
+    }
+
+    modifier isSuspended()
+    {
+        require(suspended);
+        _;
+    }
+
     /// @dev Disable default function.
     function ()
         payable
@@ -134,6 +150,7 @@ contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
         uint    value
         )
         onlyAuthorized
+        notSuspended
         external
     {
         if (value > 0 && from != to && to != 0x0) {
@@ -151,6 +168,7 @@ contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
         bytes32[] batch
         )
         onlyAuthorized
+        notSuspended
         external
     {
         // require(batch.length % 9 == 0);
@@ -306,6 +324,7 @@ contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
         uint    cancelAmount
         )
         onlyAuthorized
+        notSuspended
         external
     {
         cancelled[orderHash] = cancelled[orderHash].add(cancelAmount);
@@ -316,15 +335,18 @@ contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
         uint    cancelOrFillAmount
         )
         onlyAuthorized
-        external
+        notSuspended
+        public
     {
         cancelledOrFilled[orderHash] = cancelledOrFilled[orderHash].add(cancelOrFillAmount);
     }
 
+
     function setCutoffs(
         uint cutoff
         )
         onlyAuthorized
+        notSuspended
         external
     {
         cutoffs[tx.origin] = cutoff;
@@ -335,6 +357,7 @@ contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
         uint    cutoff
         )
         onlyAuthorized
+        notSuspended
         external
     {
         tradingPairCutoffs[tx.origin][tokenPair] = cutoff;
@@ -358,4 +381,29 @@ contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
         }
     }
 
+    function suspend()
+        onlyOwner
+        notSuspended
+        public
+    {
+        suspended = true;
+    }
+
+    function resume()
+        onlyOwner
+        isSuspended
+        public
+    {
+        suspended = false;
+    }
+
+    /// owner must suspend delegate first before invoke kill method.
+    function kill()
+        onlyOwner
+        isSuspended
+        external
+    {
+        owner = 0x0;
+        emit OwnershipTransferred(owner, 0x0);
+    }
 }