fix: major audit issue (sub tree root)

zkopru-network · Oct 10, 2021 · c3a447c · c3a447c
1 parent 52b7cf6
commit c3a447c
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Showing 2 changed files with 5 additions and 4 deletions.
diff --git a/packages/contracts/contracts/zkopru/controllers/UserInteractable.sol b/packages/contracts/contracts/zkopru/controllers/UserInteractable.sol
@@ -152,7 +152,8 @@ contract UserInteractable is Storage {
             "Prepay data is different with the given withdrawal note."
         );
         require(
-            prepayRequest.prepayer == address(0) || prepayRequest.prepayer == msg.sender,
+            prepayRequest.prepayer == address(0) ||
+                prepayRequest.prepayer == msg.sender,
             "This tx should be from the prepayer."
         );
 

diff --git a/packages/contracts/contracts/zkopru/libraries/MerkleTree.sol b/packages/contracts/contracts/zkopru/libraries/MerkleTree.sol
@@ -355,7 +355,7 @@ library SubTreeLib {
         require(leaves.length <= treeSize, "Overflowed");
 
         uint256[] memory nodes = new uint256[](treeSize << 1); // we'll not use nodes[0]
-        uint256 emptyNode = treeSize + leaves.length; // we do not hash if we can use pre hashed zeroes
+        uint256 lastNotEmptyNode = treeSize + leaves.length - 1;
 
         // From the bottom to the top
         for (uint256 level = 0; level <= subTreeDepth; level++) {
@@ -366,7 +366,7 @@ library SubTreeLib {
                 nodeIndex >= leftMostOfTheFloor;
                 nodeIndex--
             ) {
-                if (nodeIndex < emptyNode) {
+                if (nodeIndex <= lastNotEmptyNode) {
                     // This node is not an empty node
                     if (level == 0) {
                         // Leaf node
@@ -385,7 +385,7 @@ library SubTreeLib {
                     nodes[nodeIndex] = self.preHashedZero[level];
                 }
             }
-            emptyNode >>= 1;
+            lastNotEmptyNode >>= 1;
         }
         return nodes[1];
     }