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Check signatures before respend relay

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Check that all inputs are completely valid before actually
relaying a double-spend.
This commit is contained in:
Tom Harding 2014-07-01 14:26:57 -07:00
parent f04f123407
commit 88dd3598d2
1 changed files with 22 additions and 15 deletions
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37
src/main.cpp
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@ -127,7 +127,7 @@ namespace {
// Forward reference functions defined here: // Forward reference functions defined here:
static const unsigned int MAX_DOUBLESPEND_BLOOM = 1000; static const unsigned int MAX_DOUBLESPEND_BLOOM = 1000;
static void RelayDoubleSpend(const COutPoint& outPoint, const CTransaction& doubleSpend, bool fInBlock, CBloomFilter& filter); static bool RelayableRespend(const COutPoint& outPoint, const CTransaction& doubleSpend, bool fInBlock, CBloomFilter& filter);
////////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////
// //
@ -156,7 +156,7 @@ struct CMainSignals {
// transaction was first seen in a block. // transaction was first seen in a block.
// Note: only notifies if the previous transaction is in the memory pool; if previous transction was in a block, // Note: only notifies if the previous transaction is in the memory pool; if previous transction was in a block,
// then the double-spend simply fails when we try to lookup the inputs in the current UTXO set. // then the double-spend simply fails when we try to lookup the inputs in the current UTXO set.
boost::signals2::signal<void (const COutPoint&, const CTransaction&, bool)> DetectedDoubleSpend; boost::signals2::signal<bool (const COutPoint&, const CTransaction&, bool)> DetectedDoubleSpend;
} g_signals; } g_signals;
} // anon namespace } // anon namespace
@ -166,7 +166,7 @@ void RegisterInternalSignals() {
seed_insecure_rand(); seed_insecure_rand();
doubleSpendFilter = CBloomFilter(MAX_DOUBLESPEND_BLOOM, 0.01, insecure_rand(), BLOOM_UPDATE_NONE); doubleSpendFilter = CBloomFilter(MAX_DOUBLESPEND_BLOOM, 0.01, insecure_rand(), BLOOM_UPDATE_NONE);
g_signals.DetectedDoubleSpend.connect(boost::bind(RelayDoubleSpend, _1, _2, _3, doubleSpendFilter)); g_signals.DetectedDoubleSpend.connect(boost::bind(RelayableRespend, _1, _2, _3, doubleSpendFilter));
} }
@ -936,6 +936,7 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
return false; return false;
// Check for conflicts with in-memory transactions // Check for conflicts with in-memory transactions
bool relayableRespend = false;
{ {
LOCK(pool.cs); // protect pool.mapNextTx LOCK(pool.cs); // protect pool.mapNextTx
for (unsigned int i = 0; i < tx.vin.size(); i++) for (unsigned int i = 0; i < tx.vin.size(); i++)
@ -944,8 +945,9 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
// Does tx conflict with a member of the pool, and is it not equivalent to that member? // Does tx conflict with a member of the pool, and is it not equivalent to that member?
if (pool.mapNextTx.count(outpoint) && !tx.IsEquivalentTo(*pool.mapNextTx[outpoint].ptx)) if (pool.mapNextTx.count(outpoint) && !tx.IsEquivalentTo(*pool.mapNextTx[outpoint].ptx))
{ {
g_signals.DetectedDoubleSpend(outpoint, tx, false); relayableRespend = g_signals.DetectedDoubleSpend(outpoint, tx, false);
return false; if (!relayableRespend)
return false;
} }
} }
} }
@ -1038,16 +1040,24 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
{ {
return error("AcceptToMemoryPool: : ConnectInputs failed %s", hash.ToString()); return error("AcceptToMemoryPool: : ConnectInputs failed %s", hash.ToString());
} }
// Store transaction in memory
pool.addUnchecked(hash, entry); if (relayableRespend)
{
RelayTransaction(tx);
}
else
{
// Store transaction in memory
pool.addUnchecked(hash, entry);
}
} }
g_signals.SyncTransaction(tx, NULL); g_signals.SyncTransaction(tx, NULL);
return true; return !relayableRespend;
} }
static void RelayDoubleSpend(const COutPoint& outPoint, const CTransaction& doubleSpend, bool fInBlock, CBloomFilter& filter) static bool RelayableRespend(const COutPoint& outPoint, const CTransaction& doubleSpend, bool fInBlock, CBloomFilter& filter)
{ {
// Relaying double-spend attempts to our peers lets them detect when // Relaying double-spend attempts to our peers lets them detect when
// somebody might be trying to cheat them. However, blindly relaying // somebody might be trying to cheat them. However, blindly relaying
@ -1060,7 +1070,7 @@ static void RelayDoubleSpend(const COutPoint& outPoint, const CTransaction& doub
// from us they are very likely to hear about it from another peer, since // from us they are very likely to hear about it from another peer, since
// each peer uses a different, randomized bloom filter. // each peer uses a different, randomized bloom filter.
if (fInBlock || filter.contains(outPoint)) return; if (fInBlock || filter.contains(outPoint)) return false;
// Apply an independent rate limit to double-spend relays // Apply an independent rate limit to double-spend relays
static double dRespendCount; static double dRespendCount;
@ -1071,7 +1081,7 @@ static void RelayDoubleSpend(const COutPoint& outPoint, const CTransaction& doub
if (RateLimitExceeded(dRespendCount, nLastRespendTime, nRespendLimit, nSize)) if (RateLimitExceeded(dRespendCount, nLastRespendTime, nRespendLimit, nSize))
{ {
LogPrint("mempool", "Double-spend relay rejected by rate limiter\n"); LogPrint("mempool", "Double-spend relay rejected by rate limiter\n");
return; return false;
} }
LogPrint("mempool", "Rate limit dRespendCount: %g => %g\n", dRespendCount, dRespendCount+nSize); LogPrint("mempool", "Rate limit dRespendCount: %g => %g\n", dRespendCount, dRespendCount+nSize);
@ -1083,10 +1093,7 @@ static void RelayDoubleSpend(const COutPoint& outPoint, const CTransaction& doub
filter.insert(outPoint); filter.insert(outPoint);
RelayTransaction(doubleSpend); return true;
// Share conflict with wallet
g_signals.SyncTransaction(doubleSpend, NULL);
} }