be16f80abc
Any projects which want to use Hush code from now on will need to be licensed as GPLv3 or we will send the lawyers: https://www.softwarefreedom.org/ Notably, Komodo (KMD) is licensed as GPLv2 and is no longer compatible to receive code changes, without causing legal issues. MIT projects, such as Zcash, also cannot pull in changes from the Hush Full Node without permission from The Hush Developers, which may in some circumstances grant an MIT license on a case-by-case basis.
177 lines
6.8 KiB
C++
177 lines
6.8 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2014 The Bitcoin Core developers
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// Distributed under the GPLv3 software license, see the accompanying
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// file COPYING or https://www.gnu.org/licenses/gpl-3.0.en.html
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/******************************************************************************
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* Copyright © 2014-2019 The SuperNET Developers. *
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* *
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* See the AUTHORS, DEVELOPER-AGREEMENT and LICENSE files at *
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* the top-level directory of this distribution for the individual copyright *
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* holder information and the developer policies on copyright and licensing. *
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* *
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* Unless otherwise agreed in a custom licensing agreement, no part of the *
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* SuperNET software, including this file may be copied, modified, propagated *
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* or distributed except according to the terms contained in the LICENSE file *
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* *
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* Removal or modification of this copyright notice is prohibited. *
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* *
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******************************************************************************/
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#include "primitives/block.h"
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#include "hash.h"
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#include "tinyformat.h"
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#include "utilstrencodings.h"
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#include "crypto/common.h"
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#include "komodo_defs.h"
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// default hash algorithm for block
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uint256 (CBlockHeader::*CBlockHeader::hashFunction)() const = &CBlockHeader::GetSHA256DHash;
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uint256 CBlockHeader::GetSHA256DHash() const
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{
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return SerializeHash(*this);
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}
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void CBlockHeader::SetSHA256DHash()
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{
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CBlockHeader::hashFunction = &CBlockHeader::GetSHA256DHash;
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}
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uint256 BuildMerkleTree(bool* fMutated, const std::vector<uint256> leaves,
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std::vector<uint256> &vMerkleTree)
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{
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/* WARNING! If you're reading this because you're learning about crypto
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and/or designing a new system that will use merkle trees, keep in mind
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that the following merkle tree algorithm has a serious flaw related to
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duplicate txids, resulting in a vulnerability (CVE-2012-2459).
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The reason is that if the number of hashes in the list at a given time
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is odd, the last one is duplicated before computing the next level (which
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is unusual in Merkle trees). This results in certain sequences of
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transactions leading to the same merkle root. For example, these two
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trees:
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A A
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/ \ / \
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B C B C
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/ \ \ / \ / \
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D E F D E F F
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/ \ / \ / \ / \ / \ / \ / \
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1 2 3 4 5 6 1 2 3 4 5 6 5 6
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for transaction lists [1,2,3,4,5,6] and [1,2,3,4,5,6,5,6] (where 5 and
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6 are repeated) result in the same root hash A (because the hash of both
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of (F) and (F,F) is C).
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The vulnerability results from being able to send a block with such a
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transaction list, with the same merkle root, and the same block hash as
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the original without duplication, resulting in failed validation. If the
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receiving node proceeds to mark that block as permanently invalid
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however, it will fail to accept further unmodified (and thus potentially
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valid) versions of the same block. We defend against this by detecting
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the case where we would hash two identical hashes at the end of the list
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together, and treating that identically to the block having an invalid
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merkle root. Assuming no double-SHA256 collisions, this will detect all
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known ways of changing the transactions without affecting the merkle
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root.
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*/
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vMerkleTree.clear();
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vMerkleTree.reserve(leaves.size() * 2 + 16); // Safe upper bound for the number of total nodes.
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for (std::vector<uint256>::const_iterator it(leaves.begin()); it != leaves.end(); ++it)
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vMerkleTree.push_back(*it);
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int j = 0;
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bool mutated = false;
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for (int nSize = leaves.size(); nSize > 1; nSize = (nSize + 1) / 2)
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{
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for (int i = 0; i < nSize; i += 2)
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{
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int i2 = std::min(i+1, nSize-1);
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if (i2 == i + 1 && i2 + 1 == nSize && vMerkleTree[j+i] == vMerkleTree[j+i2]) {
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// Two identical hashes at the end of the list at a particular level.
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mutated = true;
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}
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vMerkleTree.push_back(Hash(BEGIN(vMerkleTree[j+i]), END(vMerkleTree[j+i]),
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BEGIN(vMerkleTree[j+i2]), END(vMerkleTree[j+i2])));
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}
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j += nSize;
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}
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if (fMutated) {
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*fMutated = mutated;
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}
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return (vMerkleTree.empty() ? uint256() : vMerkleTree.back());
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}
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uint256 CBlock::BuildMerkleTree(bool* fMutated) const
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{
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std::vector<uint256> leaves;
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for (int i=0; i<vtx.size(); i++) leaves.push_back(vtx[i].GetHash());
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return ::BuildMerkleTree(fMutated, leaves, vMerkleTree);
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}
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std::vector<uint256> GetMerkleBranch(int nIndex, int nLeaves, const std::vector<uint256> &vMerkleTree)
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{
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std::vector<uint256> vMerkleBranch;
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int j = 0;
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for (int nSize = nLeaves; nSize > 1; nSize = (nSize + 1) / 2)
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{
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int i = std::min(nIndex^1, nSize-1);
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vMerkleBranch.push_back(vMerkleTree[j+i]);
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nIndex >>= 1;
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j += nSize;
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}
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return vMerkleBranch;
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}
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std::vector<uint256> CBlock::GetMerkleBranch(int nIndex) const
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{
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if (vMerkleTree.empty())
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BuildMerkleTree();
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return ::GetMerkleBranch(nIndex, vtx.size(), vMerkleTree);
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}
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uint256 CBlock::CheckMerkleBranch(uint256 hash, const std::vector<uint256>& vMerkleBranch, int nIndex)
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{
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if (nIndex == -1)
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return uint256();
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for (std::vector<uint256>::const_iterator it(vMerkleBranch.begin()); it != vMerkleBranch.end(); ++it)
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{
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if (nIndex & 1)
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hash = Hash(BEGIN(*it), END(*it), BEGIN(hash), END(hash));
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else
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hash = Hash(BEGIN(hash), END(hash), BEGIN(*it), END(*it));
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nIndex >>= 1;
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}
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return hash;
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}
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std::string CBlock::ToString() const
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{
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std::stringstream s;
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s << strprintf("CBlock(hash=%s, ver=%d, hashPrevBlock=%s, hashMerkleRoot=%s, hashFinalSaplingRoot=%s, nTime=%u, nBits=%08x, nNonce=%s, vtx=%u)\n",
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GetHash().ToString(),
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nVersion,
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hashPrevBlock.ToString(),
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hashMerkleRoot.ToString(),
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hashFinalSaplingRoot.ToString(),
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nTime, nBits, nNonce.ToString(),
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vtx.size());
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for (unsigned int i = 0; i < vtx.size(); i++)
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{
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s << " " << vtx[i].ToString() << "\n";
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}
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s << " vMerkleTree: ";
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for (unsigned int i = 0; i < vMerkleTree.size(); i++)
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s << " " << vMerkleTree[i].ToString();
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s << "\n";
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return s.str();
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}
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