From 3a1f5a7c367e45d8f0784ff60c5d92a97b88e9c0 Mon Sep 17 00:00:00 2001
From: wangdong <wangdong@zhongan.io>
Date: Mon, 23 Apr 2018 09:48:33 -0400
Subject: [PATCH] more security fix

---
 contracts/TokenTransferDelegate.sol     | 6 +++---
 contracts/TokenTransferDelegateImpl.sol | 2 +-
 contracts/lib/MathUint.sol              | 4 ++--
 contracts/lib/MultihashUtil.sol         | 4 ++--
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/contracts/TokenTransferDelegate.sol b/contracts/TokenTransferDelegate.sol
index 5c4c0b50..df9b262b 100644
--- a/contracts/TokenTransferDelegate.sol
+++ b/contracts/TokenTransferDelegate.sol
@@ -82,8 +82,8 @@ contract TokenTransferDelegate {
         external;
 
     function batchUpdateHistoryAndTransferTokens(
-        address lrcTokenAddress,
-        address minerFeeRecipient,
+        address   lrcTokenAddress,
+        address   minerFeeRecipient,
         bytes32[] historyBatch,
         bytes32[] transferBatch
         )
@@ -122,7 +122,7 @@ contract TokenTransferDelegate {
     function checkCutoffsBatch(
         address[] owners,
         bytes20[] tradingPairs,
-        uint[] validSince
+        uint[]    validSince
         )
         external
         view;
diff --git a/contracts/TokenTransferDelegateImpl.sol b/contracts/TokenTransferDelegateImpl.sol
index 30f407ff..583c5360 100644
--- a/contracts/TokenTransferDelegateImpl.sol
+++ b/contracts/TokenTransferDelegateImpl.sol
@@ -282,7 +282,7 @@ contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
         }
 
         uint walletFee = (wallet == 0x0) ? 0 : fee.mul(walletSplitPercentage) / 100;
-        uint minerFee = fee - walletFee;
+        uint minerFee = fee.sub(walletFee);
 
         if (walletFee > 0 && wallet != owner) {
             require(
diff --git a/contracts/lib/MathUint.sol b/contracts/lib/MathUint.sol
index 826de10e..437d806d 100644
--- a/contracts/lib/MathUint.sol
+++ b/contracts/lib/MathUint.sol
@@ -86,7 +86,7 @@ library MathUint {
 
         uint avg = 0;
         for (uint i = 0; i < len; i++) {
-            avg += arr[i];
+            avg = add(avg, arr[i]);
         }
 
         avg = avg / len;
@@ -101,7 +101,7 @@ library MathUint {
         for (uint i = 0; i < len; i++) {
             item = arr[i];
             s = item > avg ? item - avg : avg - item;
-            cvs += mul(s, s);
+            cvs = add(cvs, mul(s, s));
         }
 
         return ((mul(mul(cvs, scale), scale) / avg) / avg) / (len - 1);
diff --git a/contracts/lib/MultihashUtil.sol b/contracts/lib/MultihashUtil.sol
index 029096af..6e504223 100644
--- a/contracts/lib/MultihashUtil.sol
+++ b/contracts/lib/MultihashUtil.sol
@@ -49,8 +49,8 @@ library MultihashUtil {
             require(
                 signer == ecrecover(
                     keccak256(
-                      SIG_PREFIX,
-                      plaintext
+                        SIG_PREFIX,
+                        plaintext
                     ),
                     uint8(multihash[2]),
                     BytesUtil.bytesToBytes32(multihash, 3),