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Merge #10192: Cache full script execution results in addition to signatures

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e3f9c05 Add CheckInputs() unit tests (Suhas Daftuar)
a3543af Better document CheckInputs parameter meanings (Matt Corallo)
309ee1a Update -maxsigcachesize doc clarify init logprints for it (Matt Corallo)
b014668 Add CheckInputs wrapper CCoinsViewMemPool -> non-consensus-critical (Matt Corallo)
eada04e Do not print soft-fork-script warning with -promiscuousmempool (Matt Corallo)
b5fea8d Cache full script execution results in addition to signatures (Matt Corallo)
6d22b2b Pull script verify flags calculation out of ConnectBlock (Matt Corallo)

Tree-SHA512: 0c6c3c79c64fcb21e17ab60290c5c96d4fac11624c49f841a4201eec21cb480314c52a07d1e3abd4f9c764785cc57bfd178511f495aa0469addb204e96214fe4
This commit is contained in:
Wladimir J. van der Laan
2017-06-29 20:04:07 +02:00
parent 0c3542e5de e3f9c05b96
commit 2935b469ae
6 changed files with 449 additions and 43 deletions
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195
src/validation.cpp
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@@ -14,6 +14,7 @@
#include "consensus/merkle.h"
#include "consensus/tx_verify.h"
#include "consensus/validation.h"
#include "cuckoocache.h"
#include "fs.h"
#include "hash.h"
#include "init.h"
@@ -189,7 +190,7 @@ enum FlushStateMode {
static bool FlushStateToDisk(const CChainParams& chainParams, CValidationState &state, FlushStateMode mode, int nManualPruneHeight=0);
static void FindFilesToPruneManual(std::set<int>& setFilesToPrune, int nManualPruneHeight);
static void FindFilesToPrune(std::set<int>& setFilesToPrune, uint64_t nPruneAfterHeight);
static bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, PrecomputedTransactionData& txdata, std::vector<CScriptCheck> *pvChecks = NULL);
bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, std::vector<CScriptCheck> *pvChecks = nullptr);
static FILE* OpenUndoFile(const CDiskBlockPos &pos, bool fReadOnly = false);
bool CheckFinalTx(const CTransaction &tx, int flags)
@@ -312,6 +313,9 @@ bool CheckSequenceLocks(const CTransaction &tx, int flags, LockPoints* lp, bool
return EvaluateSequenceLocks(index, lockPair);
}
// Returns the script flags which should be checked for a given block
static unsigned int GetBlockScriptFlags(const CBlockIndex* pindex, const Consensus::Params& chainparams);
static void LimitMempoolSize(CTxMemPool& pool, size_t limit, unsigned long age) {
int expired = pool.Expire(GetTime() - age);
if (expired != 0) {
@@ -395,6 +399,42 @@ void UpdateMempoolForReorg(DisconnectedBlockTransactions &disconnectpool, bool f
LimitMempoolSize(mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
}
// Used to avoid mempool polluting consensus critical paths if CCoinsViewMempool
// were somehow broken and returning the wrong scriptPubKeys
static bool CheckInputsFromMempoolAndCache(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &view, CTxMemPool& pool,
unsigned int flags, bool cacheSigStore, PrecomputedTransactionData& txdata) {
AssertLockHeld(cs_main);
// pool.cs should be locked already, but go ahead and re-take the lock here
// to enforce that mempool doesn't change between when we check the view
// and when we actually call through to CheckInputs
LOCK(pool.cs);
assert(!tx.IsCoinBase());
for (const CTxIn& txin : tx.vin) {
const Coin& coin = view.AccessCoin(txin.prevout);
// At this point we haven't actually checked if the coins are all
// available (or shouldn't assume we have, since CheckInputs does).
// So we just return failure if the inputs are not available here,
// and then only have to check equivalence for available inputs.
if (coin.IsSpent()) return false;
const CTransactionRef& txFrom = pool.get(txin.prevout.hash);
if (txFrom) {
assert(txFrom->GetHash() == txin.prevout.hash);
assert(txFrom->vout.size() > txin.prevout.n);
assert(txFrom->vout[txin.prevout.n] == coin.out);
} else {
const Coin& coinFromDisk = pcoinsTip->AccessCoin(txin.prevout);
assert(!coinFromDisk.IsSpent());
assert(coinFromDisk.out == coin.out);
}
}
return CheckInputs(tx, state, view, true, flags, cacheSigStore, true, txdata);
}
static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool& pool, CValidationState& state, const CTransactionRef& ptx, bool fLimitFree,
bool* pfMissingInputs, int64_t nAcceptTime, std::list<CTransactionRef>* plTxnReplaced,
bool fOverrideMempoolLimit, const CAmount& nAbsurdFee, std::vector<COutPoint>& coins_to_uncache)
@@ -751,32 +791,51 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
// Check against previous transactions
// This is done last to help prevent CPU exhaustion denial-of-service attacks.
PrecomputedTransactionData txdata(tx);
if (!CheckInputs(tx, state, view, true, scriptVerifyFlags, true, txdata)) {
if (!CheckInputs(tx, state, view, true, scriptVerifyFlags, true, false, txdata)) {
// SCRIPT_VERIFY_CLEANSTACK requires SCRIPT_VERIFY_WITNESS, so we
// need to turn both off, and compare against just turning off CLEANSTACK
// to see if the failure is specifically due to witness validation.
CValidationState stateDummy; // Want reported failures to be from first CheckInputs
if (!tx.HasWitness() && CheckInputs(tx, stateDummy, view, true, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, txdata) &&
!CheckInputs(tx, stateDummy, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, txdata)) {
if (!tx.HasWitness() && CheckInputs(tx, stateDummy, view, true, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, false, txdata) &&
!CheckInputs(tx, stateDummy, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, false, txdata)) {
// Only the witness is missing, so the transaction itself may be fine.
state.SetCorruptionPossible();
}
return false; // state filled in by CheckInputs
}
// Check again against just the consensus-critical mandatory script
// verification flags, in case of bugs in the standard flags that cause
// Check again against the current block tip's script verification
// flags to cache our script execution flags. This is, of course,
// useless if the next block has different script flags from the
// previous one, but because the cache tracks script flags for us it
// will auto-invalidate and we'll just have a few blocks of extra
// misses on soft-fork activation.
//
// This is also useful in case of bugs in the standard flags that cause
// transactions to pass as valid when they're actually invalid. For
// instance the STRICTENC flag was incorrectly allowing certain
// CHECKSIG NOT scripts to pass, even though they were invalid.
//
// There is a similar check in CreateNewBlock() to prevent creating
// invalid blocks, however allowing such transactions into the mempool
// can be exploited as a DoS attack.
if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true, txdata))
// invalid blocks (using TestBlockValidity), however allowing such
// transactions into the mempool can be exploited as a DoS attack.
unsigned int currentBlockScriptVerifyFlags = GetBlockScriptFlags(chainActive.Tip(), Params().GetConsensus());
if (!CheckInputsFromMempoolAndCache(tx, state, view, pool, currentBlockScriptVerifyFlags, true, txdata))
{
return error("%s: BUG! PLEASE REPORT THIS! ConnectInputs failed against MANDATORY but not STANDARD flags %s, %s",
__func__, hash.ToString(), FormatStateMessage(state));
// If we're using promiscuousmempoolflags, we may hit this normally
// Check if current block has some flags that scriptVerifyFlags
// does not before printing an ominous warning
if (!(~scriptVerifyFlags & currentBlockScriptVerifyFlags)) {
return error("%s: BUG! PLEASE REPORT THIS! ConnectInputs failed against latest-block but not STANDARD flags %s, %s",
__func__, hash.ToString(), FormatStateMessage(state));
} else {
if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true, false, txdata)) {
return error("%s: ConnectInputs failed against MANDATORY but not STANDARD flags due to promiscuous mempool %s, %s",
__func__, hash.ToString(), FormatStateMessage(state));
} else {
LogPrintf("Warning: -promiscuousmempool flags set to not include currently enforced soft forks, this may break mining or otherwise cause instability!\n");
}
}
}
// Remove conflicting transactions from the mempool
@@ -1152,12 +1211,34 @@ int GetSpendHeight(const CCoinsViewCache& inputs)
return pindexPrev->nHeight + 1;
}
static CuckooCache::cache<uint256, SignatureCacheHasher> scriptExecutionCache;
static uint256 scriptExecutionCacheNonce(GetRandHash());
void InitScriptExecutionCache() {
// nMaxCacheSize is unsigned. If -maxsigcachesize is set to zero,
// setup_bytes creates the minimum possible cache (2 elements).
size_t nMaxCacheSize = std::min(std::max((int64_t)0, GetArg("-maxsigcachesize", DEFAULT_MAX_SIG_CACHE_SIZE) / 2), MAX_MAX_SIG_CACHE_SIZE) * ((size_t) 1 << 20);
size_t nElems = scriptExecutionCache.setup_bytes(nMaxCacheSize);
LogPrintf("Using %zu MiB out of %zu/2 requested for script execution cache, able to store %zu elements\n",
(nElems*sizeof(uint256)) >>20, (nMaxCacheSize*2)>>20, nElems);
}
/**
* Check whether all inputs of this transaction are valid (no double spends, scripts & sigs, amounts)
* This does not modify the UTXO set. If pvChecks is not NULL, script checks are pushed onto it
* instead of being performed inline.
* This does not modify the UTXO set.
*
* If pvChecks is not NULL, script checks are pushed onto it instead of being performed inline. Any
* script checks which are not necessary (eg due to script execution cache hits) are, obviously,
* not pushed onto pvChecks/run.
*
* Setting cacheSigStore/cacheFullScriptStore to false will remove elements from the corresponding cache
* which are matched. This is useful for checking blocks where we will likely never need the cache
* entry again.
*
* Non-static (and re-declared) in src/test/txvalidationcache_tests.cpp
*/
static bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, PrecomputedTransactionData& txdata, std::vector<CScriptCheck> *pvChecks)
bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, std::vector<CScriptCheck> *pvChecks)
{
if (!tx.IsCoinBase())
{
@@ -1177,6 +1258,21 @@ static bool CheckInputs(const CTransaction& tx, CValidationState &state, const C
// Of course, if an assumed valid block is invalid due to false scriptSigs
// this optimization would allow an invalid chain to be accepted.
if (fScriptChecks) {
// First check if script executions have been cached with the same
// flags. Note that this assumes that the inputs provided are
// correct (ie that the transaction hash which is in tx's prevouts
// properly commits to the scriptPubKey in the inputs view of that
// transaction).
uint256 hashCacheEntry;
// We only use the first 19 bytes of nonce to avoid a second SHA
// round - giving us 19 + 32 + 4 = 55 bytes (+ 8 + 1 = 64)
static_assert(55 - sizeof(flags) - 32 >= 128/8, "Want at least 128 bits of nonce for script execution cache");
CSHA256().Write(scriptExecutionCacheNonce.begin(), 55 - sizeof(flags) - 32).Write(tx.GetWitnessHash().begin(), 32).Write((unsigned char*)&flags, sizeof(flags)).Finalize(hashCacheEntry.begin());
AssertLockHeld(cs_main); //TODO: Remove this requirement by making CuckooCache not require external locks
if (scriptExecutionCache.contains(hashCacheEntry, !cacheFullScriptStore)) {
return true;
}
for (unsigned int i = 0; i < tx.vin.size(); i++) {
const COutPoint &prevout = tx.vin[i].prevout;
const Coin& coin = inputs.AccessCoin(prevout);
@@ -1191,7 +1287,7 @@ static bool CheckInputs(const CTransaction& tx, CValidationState &state, const C
const CAmount amount = coin.out.nValue;
// Verify signature
CScriptCheck check(scriptPubKey, amount, tx, i, flags, cacheStore, &txdata);
CScriptCheck check(scriptPubKey, amount, tx, i, flags, cacheSigStore, &txdata);
if (pvChecks) {
pvChecks->push_back(CScriptCheck());
check.swap(pvChecks->back());
@@ -1204,7 +1300,7 @@ static bool CheckInputs(const CTransaction& tx, CValidationState &state, const C
// avoid splitting the network between upgraded and
// non-upgraded nodes.
CScriptCheck check2(scriptPubKey, amount, tx, i,
flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheStore, &txdata);
flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheSigStore, &txdata);
if (check2())
return state.Invalid(false, REJECT_NONSTANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check.GetScriptError())));
}
@@ -1218,6 +1314,12 @@ static bool CheckInputs(const CTransaction& tx, CValidationState &state, const C
return state.DoS(100,false, REJECT_INVALID, strprintf("mandatory-script-verify-flag-failed (%s)", ScriptErrorString(check.GetScriptError())));
}
}
if (cacheFullScriptStore && !pvChecks) {
// We executed all of the provided scripts, and were told to
// cache the result. Do so now.
scriptExecutionCache.insert(hashCacheEntry);
}
}
}
@@ -1481,6 +1583,41 @@ public:
// Protected by cs_main
static ThresholdConditionCache warningcache[VERSIONBITS_NUM_BITS];
static unsigned int GetBlockScriptFlags(const CBlockIndex* pindex, const Consensus::Params& consensusparams) {
AssertLockHeld(cs_main);
// BIP16 didn't become active until Apr 1 2012
int64_t nBIP16SwitchTime = 1333238400;
bool fStrictPayToScriptHash = (pindex->GetBlockTime() >= nBIP16SwitchTime);
unsigned int flags = fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE;
// Start enforcing the DERSIG (BIP66) rule
if (pindex->nHeight >= consensusparams.BIP66Height) {
flags |= SCRIPT_VERIFY_DERSIG;
}
// Start enforcing CHECKLOCKTIMEVERIFY (BIP65) rule
if (pindex->nHeight >= consensusparams.BIP65Height) {
flags |= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
}
// Start enforcing BIP68 (sequence locks) and BIP112 (CHECKSEQUENCEVERIFY) using versionbits logic.
if (VersionBitsState(pindex->pprev, consensusparams, Consensus::DEPLOYMENT_CSV, versionbitscache) == THRESHOLD_ACTIVE) {
flags |= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY;
}
// Start enforcing WITNESS rules using versionbits logic.
if (IsWitnessEnabled(pindex->pprev, consensusparams)) {
flags |= SCRIPT_VERIFY_WITNESS;
flags |= SCRIPT_VERIFY_NULLDUMMY;
}
return flags;
}
static int64_t nTimeCheck = 0;
static int64_t nTimeForks = 0;
static int64_t nTimeVerify = 0;
@@ -1584,34 +1721,14 @@ static bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockInd
}
}
// BIP16 didn't become active until Apr 1 2012
int64_t nBIP16SwitchTime = 1333238400;
bool fStrictPayToScriptHash = (pindex->GetBlockTime() >= nBIP16SwitchTime);
unsigned int flags = fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE;
// Start enforcing the DERSIG (BIP66) rule
if (pindex->nHeight >= chainparams.GetConsensus().BIP66Height) {
flags |= SCRIPT_VERIFY_DERSIG;
}
// Start enforcing CHECKLOCKTIMEVERIFY (BIP65) rule
if (pindex->nHeight >= chainparams.GetConsensus().BIP65Height) {
flags |= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
}
// Start enforcing BIP68 (sequence locks) and BIP112 (CHECKSEQUENCEVERIFY) using versionbits logic.
int nLockTimeFlags = 0;
if (VersionBitsState(pindex->pprev, chainparams.GetConsensus(), Consensus::DEPLOYMENT_CSV, versionbitscache) == THRESHOLD_ACTIVE) {
flags |= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY;
nLockTimeFlags |= LOCKTIME_VERIFY_SEQUENCE;
}
// Start enforcing WITNESS rules using versionbits logic.
if (IsWitnessEnabled(pindex->pprev, chainparams.GetConsensus())) {
flags |= SCRIPT_VERIFY_WITNESS;
flags |= SCRIPT_VERIFY_NULLDUMMY;
}
// Get the script flags for this block
unsigned int flags = GetBlockScriptFlags(pindex, chainparams.GetConsensus());
int64_t nTime2 = GetTimeMicros(); nTimeForks += nTime2 - nTime1;
LogPrint(BCLog::BENCH, " - Fork checks: %.2fms [%.2fs]\n", 0.001 * (nTime2 - nTime1), nTimeForks * 0.000001);
@@ -1672,7 +1789,7 @@ static bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockInd
std::vector<CScriptCheck> vChecks;
bool fCacheResults = fJustCheck; /* Don't cache results if we're actually connecting blocks (still consult the cache, though) */
if (!CheckInputs(tx, state, view, fScriptChecks, flags, fCacheResults, txdata[i], nScriptCheckThreads ? &vChecks : NULL))
if (!CheckInputs(tx, state, view, fScriptChecks, flags, fCacheResults, fCacheResults, txdata[i], nScriptCheckThreads ? &vChecks : NULL))
return error("ConnectBlock(): CheckInputs on %s failed with %s",
tx.GetHash().ToString(), FormatStateMessage(state));
control.Add(vChecks);