From d60128e168a98c105fa564de50bd04baa0abc838 Mon Sep 17 00:00:00 2001
From: Sean Bowe <ewillbefull@gmail.com>
Date: Thu, 7 Jan 2016 07:50:20 -0700
Subject: [PATCH] Fix padding truncation bug in deserialization

---
 libzerocash/IncrementalMerkleTree.cpp |  4 +++-
 tests/merkleTest.cpp                  | 22 ++++++++++++++++++----
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/libzerocash/IncrementalMerkleTree.cpp b/libzerocash/IncrementalMerkleTree.cpp
index 17084a6..ac898b6 100644
--- a/libzerocash/IncrementalMerkleTree.cpp
+++ b/libzerocash/IncrementalMerkleTree.cpp
@@ -80,7 +80,9 @@ namespace libzerocash {
         currentPos += hashListBytesLength;
         convertBytesVectorToVector(hashListBytes, deserialized.hashList);
         /* Remove the multiple-of-8-bits padding. */
-        deserialized.hashList.resize(deserialized.treeHeight);
+        deserialized.hashList.erase(deserialized.hashList.begin(),
+                                    deserialized.hashList.end() - deserialized.treeHeight
+                                   );
 
         /* hashVec */
         size_t hashVecSize = countOnes(deserialized.hashList);
diff --git a/tests/merkleTest.cpp b/tests/merkleTest.cpp
index 554768f..6df3509 100644
--- a/tests/merkleTest.cpp
+++ b/tests/merkleTest.cpp
@@ -113,11 +113,23 @@ BOOST_AUTO_TEST_CASE( testRootOfTreeOfNonZeroIsNonZero ) {
     BOOST_CHECK( expected_root != actual_root );
 }
 
+BOOST_AUTO_TEST_CASE( testSerializationEdgeCase ) {
+
+}
+
 BOOST_AUTO_TEST_CASE( testCompactRepresentation ) {
     for (uint32_t num_entries = 0; num_entries < 100; num_entries++) {
+        size_t test_depth = 64;
+
+        if (num_entries == 2) {
+            // This is a particular failure I'm testing with weird
+            // padding caused by this depth.
+            test_depth = 20;
+        }
+
         std::vector< std::vector<bool> > values;
         std::vector<bool> root1, root2;
-        IncrementalMerkleTree incTree(64);
+        IncrementalMerkleTree incTree(test_depth);
 
         constructNonzeroTestVector(values, num_entries);
 
@@ -126,7 +138,7 @@ BOOST_AUTO_TEST_CASE( testCompactRepresentation ) {
 
         IncrementalMerkleTreeCompact compact = incTree.getCompactRepresentation();
 
-        BOOST_REQUIRE( compact.getTreeHeight() == 64 );
+        BOOST_REQUIRE( compact.getTreeHeight() == test_depth );
 
         // Calculate what the path to the next-added element should be.
         std::vector<unsigned char> path_bytes(8);
@@ -134,8 +146,10 @@ BOOST_AUTO_TEST_CASE( testCompactRepresentation ) {
         libzerocash::convertIntToBytesVector(num_entries, path_bytes);
         libzerocash::convertBytesVectorToVector(path_bytes, path_bits);
 
-        // Make sure the paths match.
-        BOOST_REQUIRE( compact.getHashList() == path_bits );
+        if (test_depth == 64) {
+            // Make sure the paths match.
+            BOOST_REQUIRE( compact.getHashList() == path_bits );
+        }
 
         // Make sure there's a hash for every '1' bit down the path.
         BOOST_REQUIRE( compact.getHashVec().size() == libzerocash::countOnes(path_bits) );