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Do not store Merkle branches in the wallet.

Assume that when a wallet transaction has a valid block hash and transaction position
in it, the transaction is actually there. We're already trusting wallet data in a
much more fundamental way anyway.

To prevent backward compatibility issues, a new record is used for storing the
block locator in the wallet. Old wallets will see a wallet file synchronized up
to the genesis block, and rescan automatically.
tags/v0.15.1
Pieter Wuille 6 years ago
parent
commit
391dff16fe

+ 9
- 0
doc/release-notes.md View File

@@ -105,6 +105,15 @@ In this version, it is only enforced for peers that send protocol versions
removed. It is recommended to update SPV clients to check for the `NODE_BLOOM`
service bit for nodes that report versions newer than 70011.

Merkle branches removed from wallet
-----------------------------------

Previously, every wallet transaction stored a Merkle branch to prove its
presence in blocks. This wasn't being used for more than an expensive
sanity check. Since 0.12, these are no longer stored. When loading a
0.12 wallet into an older version, it will automatically rescan to avoid
failed checks.

0.12.0 Change log
=================


+ 1
- 1
src/chainparams.cpp View File

@@ -31,7 +31,7 @@ static CBlock CreateGenesisBlock(const char* pszTimestamp, const CScript& genesi
genesis.nVersion = nVersion;
genesis.vtx.push_back(txNew);
genesis.hashPrevBlock.SetNull();
genesis.hashMerkleRoot = genesis.BuildMerkleTree();
genesis.hashMerkleRoot = genesis.ComputeMerkleRoot();
return genesis;
}


+ 1
- 1
src/core_memusage.h View File

@@ -48,7 +48,7 @@ static inline size_t RecursiveDynamicUsage(const CMutableTransaction& tx) {
}

static inline size_t RecursiveDynamicUsage(const CBlock& block) {
size_t mem = memusage::DynamicUsage(block.vtx) + memusage::DynamicUsage(block.vMerkleTree);
size_t mem = memusage::DynamicUsage(block.vtx);
for (std::vector<CTransaction>::const_iterator it = block.vtx.begin(); it != block.vtx.end(); it++) {
mem += RecursiveDynamicUsage(*it);
}

+ 1
- 1
src/main.cpp View File

@@ -2595,7 +2595,7 @@ bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW, bo
// Check the merkle root.
if (fCheckMerkleRoot) {
bool mutated;
uint256 hashMerkleRoot2 = block.BuildMerkleTree(&mutated);
uint256 hashMerkleRoot2 = block.ComputeMerkleRoot(&mutated);
if (block.hashMerkleRoot != hashMerkleRoot2)
return state.DoS(100, error("CheckBlock(): hashMerkleRoot mismatch"),
REJECT_INVALID, "bad-txnmrklroot", true);

+ 1
- 1
src/miner.cpp View File

@@ -368,7 +368,7 @@ void IncrementExtraNonce(CBlock* pblock, const CBlockIndex* pindexPrev, unsigned
assert(txCoinbase.vin[0].scriptSig.size() <= 100);

pblock->vtx[0] = txCoinbase;
pblock->hashMerkleRoot = pblock->BuildMerkleTree();
pblock->hashMerkleRoot = pblock->ComputeMerkleRoot();
}

//////////////////////////////////////////////////////////////////////////////

+ 2
- 37
src/primitives/block.cpp View File

@@ -15,7 +15,7 @@ uint256 CBlockHeader::GetHash() const
return SerializeHash(*this);
}

uint256 CBlock::BuildMerkleTree(bool* fMutated) const
uint256 CBlock::ComputeMerkleRoot(bool* fMutated) const
{
/* WARNING! If you're reading this because you're learning about crypto
and/or designing a new system that will use merkle trees, keep in mind
@@ -52,7 +52,7 @@ uint256 CBlock::BuildMerkleTree(bool* fMutated) const
known ways of changing the transactions without affecting the merkle
root.
*/
vMerkleTree.clear();
std::vector<uint256> vMerkleTree;
vMerkleTree.reserve(vtx.size() * 2 + 16); // Safe upper bound for the number of total nodes.
for (std::vector<CTransaction>::const_iterator it(vtx.begin()); it != vtx.end(); ++it)
vMerkleTree.push_back(it->GetHash());
@@ -78,37 +78,6 @@ uint256 CBlock::BuildMerkleTree(bool* fMutated) const
return (vMerkleTree.empty() ? uint256() : vMerkleTree.back());
}

std::vector<uint256> CBlock::GetMerkleBranch(int nIndex) const
{
if (vMerkleTree.empty())
BuildMerkleTree();
std::vector<uint256> vMerkleBranch;
int j = 0;
for (int nSize = vtx.size(); nSize > 1; nSize = (nSize + 1) / 2)
{
int i = std::min(nIndex^1, nSize-1);
vMerkleBranch.push_back(vMerkleTree[j+i]);
nIndex >>= 1;
j += nSize;
}
return vMerkleBranch;
}

uint256 CBlock::CheckMerkleBranch(uint256 hash, const std::vector<uint256>& vMerkleBranch, int nIndex)
{
if (nIndex == -1)
return uint256();
for (std::vector<uint256>::const_iterator it(vMerkleBranch.begin()); it != vMerkleBranch.end(); ++it)
{
if (nIndex & 1)
hash = Hash(BEGIN(*it), END(*it), BEGIN(hash), END(hash));
else
hash = Hash(BEGIN(hash), END(hash), BEGIN(*it), END(*it));
nIndex >>= 1;
}
return hash;
}

std::string CBlock::ToString() const
{
std::stringstream s;
@@ -123,9 +92,5 @@ std::string CBlock::ToString() const
{
s << " " << vtx[i].ToString() << "\n";
}
s << " vMerkleTree: ";
for (unsigned int i = 0; i < vMerkleTree.size(); i++)
s << " " << vMerkleTree[i].ToString();
s << "\n";
return s.str();
}

+ 2
- 8
src/primitives/block.h View File

@@ -77,9 +77,6 @@ public:
// network and disk
std::vector<CTransaction> vtx;

// memory only
mutable std::vector<uint256> vMerkleTree;

CBlock()
{
SetNull();
@@ -103,7 +100,6 @@ public:
{
CBlockHeader::SetNull();
vtx.clear();
vMerkleTree.clear();
}

CBlockHeader GetBlockHeader() const
@@ -118,14 +114,12 @@ public:
return block;
}

// Build the in-memory merkle tree for this block and return the merkle root.
// Build the merkle tree for this block and return the merkle root.
// If non-NULL, *mutated is set to whether mutation was detected in the merkle
// tree (a duplication of transactions in the block leading to an identical
// merkle root).
uint256 BuildMerkleTree(bool* mutated = NULL) const;
uint256 ComputeMerkleRoot(bool* mutated = NULL) const;

std::vector<uint256> GetMerkleBranch(int nIndex) const;
static uint256 CheckMerkleBranch(uint256 hash, const std::vector<uint256>& vMerkleBranch, int nIndex);
std::string ToString() const;
};


+ 1
- 1
src/test/miner_tests.cpp View File

@@ -87,7 +87,7 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
pblock->vtx[0] = CTransaction(txCoinbase);
if (txFirst.size() < 2)
txFirst.push_back(new CTransaction(pblock->vtx[0]));
pblock->hashMerkleRoot = pblock->BuildMerkleTree();
pblock->hashMerkleRoot = pblock->ComputeMerkleRoot();
pblock->nNonce = blockinfo[i].nonce;
CValidationState state;
BOOST_CHECK(ProcessNewBlock(state, NULL, pblock, true, NULL));

+ 1
- 1
src/test/pmt_tests.cpp View File

@@ -48,7 +48,7 @@ BOOST_AUTO_TEST_CASE(pmt_test1)
}

// calculate actual merkle root and height
uint256 merkleRoot1 = block.BuildMerkleTree();
uint256 merkleRoot1 = block.ComputeMerkleRoot();
std::vector<uint256> vTxid(nTx, uint256());
for (unsigned int j=0; j<nTx; j++)
vTxid[j] = block.vtx[j].GetHash();

+ 1
- 14
src/wallet/wallet.cpp View File

@@ -702,9 +702,8 @@ bool CWallet::AddToWallet(const CWalletTx& wtxIn, bool fFromLoadWallet, CWalletD
wtx.hashBlock = wtxIn.hashBlock;
fUpdated = true;
}
if (wtxIn.nIndex != -1 && (wtxIn.vMerkleBranch != wtx.vMerkleBranch || wtxIn.nIndex != wtx.nIndex))
if (wtxIn.nIndex != -1 && (wtxIn.nIndex != wtx.nIndex))
{
wtx.vMerkleBranch = wtxIn.vMerkleBranch;
wtx.nIndex = wtxIn.nIndex;
fUpdated = true;
}
@@ -2812,15 +2811,11 @@ int CMerkleTx::SetMerkleBranch(const CBlock& block)
break;
if (nIndex == (int)block.vtx.size())
{
vMerkleBranch.clear();
nIndex = -1;
LogPrintf("ERROR: SetMerkleBranch(): couldn't find tx in block\n");
return 0;
}

// Fill in merkle branch
vMerkleBranch = block.GetMerkleBranch(nIndex);

// Is the tx in a block that's in the main chain
BlockMap::iterator mi = mapBlockIndex.find(hashBlock);
if (mi == mapBlockIndex.end())
@@ -2846,14 +2841,6 @@ int CMerkleTx::GetDepthInMainChainINTERNAL(const CBlockIndex* &pindexRet) const
if (!pindex || !chainActive.Contains(pindex))
return 0;

// Make sure the merkle branch connects to this block
if (!fMerkleVerified)
{
if (CBlock::CheckMerkleBranch(GetHash(), vMerkleBranch, nIndex) != pindex->hashMerkleRoot)
return 0;
fMerkleVerified = true;
}

pindexRet = pindex;
return chainActive.Height() - pindex->nHeight + 1;
}

+ 1
- 6
src/wallet/wallet.h View File

@@ -151,13 +151,8 @@ private:

public:
uint256 hashBlock;
std::vector<uint256> vMerkleBranch;
int nIndex;

// memory only
mutable bool fMerkleVerified;


CMerkleTx()
{
Init();
@@ -172,13 +167,13 @@ public:
{
hashBlock = uint256();
nIndex = -1;
fMerkleVerified = false;
}

ADD_SERIALIZE_METHODS;

template <typename Stream, typename Operation>
inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
std::vector<uint256> vMerkleBranch; // For compatibility with older versions.
READWRITE(*(CTransaction*)this);
nVersion = this->nVersion;
READWRITE(hashBlock);

+ 4
- 2
src/wallet/walletdb.cpp View File

@@ -131,12 +131,14 @@ bool CWalletDB::EraseWatchOnly(const CScript &dest)
bool CWalletDB::WriteBestBlock(const CBlockLocator& locator)
{
nWalletDBUpdated++;
return Write(std::string("bestblock"), locator);
Write(std::string("bestblock"), CBlockLocator()); // Write empty block locator so versions that require a merkle branch automatically rescan
return Write(std::string("bestblock_nomerkle"), locator);
}

bool CWalletDB::ReadBestBlock(CBlockLocator& locator)
{
return Read(std::string("bestblock"), locator);
if (Read(std::string("bestblock"), locator) && !locator.vHave.empty()) return true;
return Read(std::string("bestblock_nomerkle"), locator);
}

bool CWalletDB::WriteOrderPosNext(int64_t nOrderPosNext)

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