From 4e1a8c29bd904b8dce47a8a7c83cf80d67fc6693 Mon Sep 17 00:00:00 2001
From: The3D <emilio@aave.com>
Date: Fri, 23 Oct 2020 16:52:22 +0200
Subject: [PATCH] Fixed wad functions in WadRayMath

---
 contracts/libraries/math/WadRayMath.sol | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/contracts/libraries/math/WadRayMath.sol b/contracts/libraries/math/WadRayMath.sol
index 696a0e09..a1a8d8f4 100644
--- a/contracts/libraries/math/WadRayMath.sol
+++ b/contracts/libraries/math/WadRayMath.sol
@@ -60,7 +60,7 @@ library WadRayMath {
 
     uint256 result = a * b + halfWAD;
 
-    require((result - halfWAD) / a == b, Errors.MULTIPLICATION_OVERFLOW);
+    require(result >= halfWAD && (result - halfWAD) / a == b, Errors.MULTIPLICATION_OVERFLOW);
 
     return result / WAD;
   }
@@ -76,13 +76,9 @@ library WadRayMath {
 
     uint256 halfB = b / 2;
 
-    uint256 result = a * WAD;
+    uint256 result = a * WAD + halfB;
 
-    require(result / WAD == a, Errors.MULTIPLICATION_OVERFLOW);
-
-    result += halfB;
-
-    require(result >= halfB, Errors.ADDITION_OVERFLOW);
+    require(result >= halfB && (result - halfB) / WAD == a, Errors.MULTIPLICATION_OVERFLOW);
 
     return result / b;
   }