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-rw-r--r--src/merkleblock.cpp30
1 files changed, 18 insertions, 12 deletions
diff --git a/src/merkleblock.cpp b/src/merkleblock.cpp
index 8618e355d7..b51b002b95 100644
--- a/src/merkleblock.cpp
+++ b/src/merkleblock.cpp
@@ -1,5 +1,5 @@
// Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2014 The Bitcoin developers
+// Copyright (c) 2009-2014 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
@@ -76,7 +76,7 @@ uint256 CPartialMerkleTree::TraverseAndExtract(int height, unsigned int pos, uns
if (nBitsUsed >= vBits.size()) {
// overflowed the bits array - failure
fBad = true;
- return 0;
+ return uint256();
}
bool fParentOfMatch = vBits[nBitsUsed++];
if (height==0 || !fParentOfMatch) {
@@ -84,7 +84,7 @@ uint256 CPartialMerkleTree::TraverseAndExtract(int height, unsigned int pos, uns
if (nHashUsed >= vHash.size()) {
// overflowed the hash array - failure
fBad = true;
- return 0;
+ return uint256();
}
const uint256 &hash = vHash[nHashUsed++];
if (height==0 && fParentOfMatch) // in case of height 0, we have a matched txid
@@ -93,10 +93,16 @@ uint256 CPartialMerkleTree::TraverseAndExtract(int height, unsigned int pos, uns
} else {
// otherwise, descend into the subtrees to extract matched txids and hashes
uint256 left = TraverseAndExtract(height-1, pos*2, nBitsUsed, nHashUsed, vMatch), right;
- if (pos*2+1 < CalcTreeWidth(height-1))
+ if (pos*2+1 < CalcTreeWidth(height-1)) {
right = TraverseAndExtract(height-1, pos*2+1, nBitsUsed, nHashUsed, vMatch);
- else
+ if (right == left) {
+ // If the left and right branch should never be identical as the transaction
+ // hashes covered by them must be unique.
+ fBad = true;
+ }
+ } else {
right = left;
+ }
// and combine them before returning
return Hash(BEGIN(left), END(left), BEGIN(right), END(right));
}
@@ -122,16 +128,16 @@ uint256 CPartialMerkleTree::ExtractMatches(std::vector<uint256> &vMatch) {
vMatch.clear();
// An empty set will not work
if (nTransactions == 0)
- return 0;
+ return uint256();
// check for excessively high numbers of transactions
if (nTransactions > MAX_BLOCK_SIZE / 60) // 60 is the lower bound for the size of a serialized CTransaction
- return 0;
+ return uint256();
// there can never be more hashes provided than one for every txid
if (vHash.size() > nTransactions)
- return 0;
+ return uint256();
// there must be at least one bit per node in the partial tree, and at least one node per hash
if (vBits.size() < vHash.size())
- return 0;
+ return uint256();
// calculate height of tree
int nHeight = 0;
while (CalcTreeWidth(nHeight) > 1)
@@ -141,12 +147,12 @@ uint256 CPartialMerkleTree::ExtractMatches(std::vector<uint256> &vMatch) {
uint256 hashMerkleRoot = TraverseAndExtract(nHeight, 0, nBitsUsed, nHashUsed, vMatch);
// verify that no problems occured during the tree traversal
if (fBad)
- return 0;
+ return uint256();
// verify that all bits were consumed (except for the padding caused by serializing it as a byte sequence)
if ((nBitsUsed+7)/8 != (vBits.size()+7)/8)
- return 0;
+ return uint256();
// verify that all hashes were consumed
if (nHashUsed != vHash.size())
- return 0;
+ return uint256();
return hashMerkleRoot;
}