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Remove IsFromMe() check in CTxMemPool::accept()

Fixes issue #2178 : attacker could penny-flood with invalid-signature
transactions to deduce which addresses belonged to your node.

I'm committing this early for code review; I still need to write up
a test plan.

Executive summary of fix: check all transactions received from the network
for penny-flood rate-limiting before adding to the memory pool. But do NOT
ratelimit transactions added to the memory pool:
  - because of blockchain reorgs
  - stored in the wallet and added at startup
  - sent from the GUI or one of the send* RPC commands (CWallet::CommitTransaction)

The limit-free-transactions code really should be a method on CNode, with
counters per-peer. But that is a bigger change for another day.
tags/v0.15.1
Gavin Andresen 8 years ago
parent
commit
ce99358f4a
4 changed files with 31 additions and 32 deletions
  1. 26
    27
      src/main.cpp
  2. 3
    3
      src/main.h
  3. 1
    1
      src/rpcrawtransaction.cpp
  4. 1
    1
      src/wallet.cpp

+ 26
- 27
src/main.cpp View File

@@ -627,7 +627,7 @@ void CTxMemPool::pruneSpent(const uint256 &hashTx, CCoins &coins)
}
}

bool CTxMemPool::accept(CTransaction &tx, bool fCheckInputs,
bool CTxMemPool::accept(CTransaction &tx, bool fCheckInputs, bool fLimitFree,
bool* pfMissingInputs)
{
if (pfMissingInputs)
@@ -733,7 +733,7 @@ bool CTxMemPool::accept(CTransaction &tx, bool fCheckInputs,

// Don't accept it if it can't get into a block
int64 txMinFee = tx.GetMinFee(1000, true, GMF_RELAY);
if (nFees < txMinFee)
if (fLimitFree && nFees < txMinFee)
return error("CTxMemPool::accept() : not enough fees %s, %"PRI64d" < %"PRI64d,
hash.ToString().c_str(),
nFees, txMinFee);
@@ -741,25 +741,24 @@ bool CTxMemPool::accept(CTransaction &tx, bool fCheckInputs,
// Continuously rate-limit free transactions
// This mitigates 'penny-flooding' -- sending thousands of free transactions just to
// be annoying or make others' transactions take longer to confirm.
if (nFees < MIN_RELAY_TX_FEE)
if (fLimitFree && nFees < MIN_RELAY_TX_FEE)
{
static CCriticalSection cs;
static double dFreeCount;
static int64 nLastTime;
int64 nNow = GetTime();

{
// Use an exponentially decaying ~10-minute window:
dFreeCount *= pow(1.0 - 1.0/600.0, (double)(nNow - nLastTime));
nLastTime = nNow;
// -limitfreerelay unit is thousand-bytes-per-minute
// At default rate it would take over a month to fill 1GB
if (dFreeCount > GetArg("-limitfreerelay", 15)*10*1000 && !IsFromMe(tx))
return error("CTxMemPool::accept() : free transaction rejected by rate limiter");
if (fDebug)
printf("Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount+nSize);
dFreeCount += nSize;
}
LOCK(cs);
// Use an exponentially decaying ~10-minute window:
dFreeCount *= pow(1.0 - 1.0/600.0, (double)(nNow - nLastTime));
nLastTime = nNow;
// -limitfreerelay unit is thousand-bytes-per-minute
// At default rate it would take over a month to fill 1GB
if (dFreeCount > GetArg("-limitfreerelay", 15)*10*1000)
return error("CTxMemPool::accept() : free transaction rejected by rate limiter");
if (fDebug)
printf("Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount+nSize);
dFreeCount += nSize;
}

// Check against previous transactions
@@ -792,9 +791,9 @@ bool CTxMemPool::accept(CTransaction &tx, bool fCheckInputs,
return true;
}

bool CTransaction::AcceptToMemoryPool(bool fCheckInputs, bool* pfMissingInputs)
bool CTransaction::AcceptToMemoryPool(bool fCheckInputs, bool fLimitFree, bool* pfMissingInputs)
{
return mempool.accept(*this, fCheckInputs, pfMissingInputs);
return mempool.accept(*this, fCheckInputs, fLimitFree, pfMissingInputs);
}

bool CTxMemPool::addUnchecked(const uint256& hash, CTransaction &tx)
@@ -905,9 +904,9 @@ int CMerkleTx::GetBlocksToMaturity() const
}


bool CMerkleTx::AcceptToMemoryPool(bool fCheckInputs)
bool CMerkleTx::AcceptToMemoryPool(bool fCheckInputs, bool fLimitFree)
{
return CTransaction::AcceptToMemoryPool(fCheckInputs);
return CTransaction::AcceptToMemoryPool(fCheckInputs, fLimitFree);
}


@@ -923,10 +922,10 @@ bool CWalletTx::AcceptWalletTransaction(bool fCheckInputs)
{
uint256 hash = tx.GetHash();
if (!mempool.exists(hash) && pcoinsTip->HaveCoins(hash))
tx.AcceptToMemoryPool(fCheckInputs);
tx.AcceptToMemoryPool(fCheckInputs, false);
}
}
return AcceptToMemoryPool(fCheckInputs);
return AcceptToMemoryPool(fCheckInputs, false);
}
return false;
}
@@ -1797,7 +1796,7 @@ bool SetBestChain(CBlockIndex* pindexNew)

// Resurrect memory transactions that were in the disconnected branch
BOOST_FOREACH(CTransaction& tx, vResurrect)
tx.AcceptToMemoryPool();
tx.AcceptToMemoryPool(true, false);

// Delete redundant memory transactions that are in the connected branch
BOOST_FOREACH(CTransaction& tx, vDelete) {
@@ -3181,7 +3180,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
pfrom->AddInventoryKnown(inv);

bool fMissingInputs = false;
if (tx.AcceptToMemoryPool(true, &fMissingInputs))
if (tx.AcceptToMemoryPool(true, true, &fMissingInputs))
{
SyncWithWallets(inv.hash, tx, NULL, true);
RelayMessage(inv, vMsg);
@@ -3203,7 +3202,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
CInv inv(MSG_TX, tx.GetHash());
bool fMissingInputs2 = false;

if (tx.AcceptToMemoryPool(true, &fMissingInputs2))
if (tx.AcceptToMemoryPool(true, true, &fMissingInputs2))
{
printf(" accepted orphan tx %s\n", inv.hash.ToString().substr(0,10).c_str());
SyncWithWallets(inv.hash, tx, NULL, true);
@@ -3214,9 +3213,9 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
}
else if (!fMissingInputs2)
{
// invalid orphan
// invalid or too-little-fee orphan
vEraseQueue.push_back(inv.hash);
printf(" removed invalid orphan tx %s\n", inv.hash.ToString().substr(0,10).c_str());
printf(" removed orphan tx %s\n", inv.hash.ToString().substr(0,10).c_str());
}
}
}

+ 3
- 3
src/main.h View File

@@ -649,7 +649,7 @@ public:
bool CheckTransaction() const;

// Try to accept this transaction into the memory pool
bool AcceptToMemoryPool(bool fCheckInputs=true, bool* pfMissingInputs=NULL);
bool AcceptToMemoryPool(bool fCheckInputs=true, bool fLimitFree = true, bool* pfMissingInputs=NULL);

protected:
static const CTxOut &GetOutputFor(const CTxIn& input, CCoinsViewCache& mapInputs);
@@ -1103,7 +1103,7 @@ public:
int GetDepthInMainChain() const { CBlockIndex *pindexRet; return GetDepthInMainChain(pindexRet); }
bool IsInMainChain() const { return GetDepthInMainChain() > 0; }
int GetBlocksToMaturity() const;
bool AcceptToMemoryPool(bool fCheckInputs=true);
bool AcceptToMemoryPool(bool fCheckInputs=true, bool fLimitFree=true);
};


@@ -1882,7 +1882,7 @@ public:
std::map<uint256, CTransaction> mapTx;
std::map<COutPoint, CInPoint> mapNextTx;

bool accept(CTransaction &tx, bool fCheckInputs, bool* pfMissingInputs);
bool accept(CTransaction &tx, bool fCheckInputs, bool fLimitFree, bool* pfMissingInputs);
bool addUnchecked(const uint256& hash, CTransaction &tx);
bool remove(const CTransaction &tx, bool fRecursive = false);
bool removeConflicts(const CTransaction &tx);

+ 1
- 1
src/rpcrawtransaction.cpp View File

@@ -546,7 +546,7 @@ Value sendrawtransaction(const Array& params, bool fHelp)
fHave = view.GetCoins(hashTx, existingCoins);
if (!fHave) {
// push to local node
if (!tx.AcceptToMemoryPool())
if (!tx.AcceptToMemoryPool(true, false))
throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX rejected");
}
}

+ 1
- 1
src/wallet.cpp View File

@@ -1279,7 +1279,7 @@ bool CWallet::CommitTransaction(CWalletTx& wtxNew, CReserveKey& reservekey)
mapRequestCount[wtxNew.GetHash()] = 0;

// Broadcast
if (!wtxNew.AcceptToMemoryPool())
if (!wtxNew.AcceptToMemoryPool(true, false))
{
// This must not fail. The transaction has already been signed and recorded.
printf("CommitTransaction() : Error: Transaction not valid");

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