Precompute sighashes

Original version by Nicolas Dorier. Precomputing version by Pieter Wuille.
This commit is contained in:
Pieter Wuille
2016-08-16 15:35:45 +02:00
parent 2c2d471e18
commit d2c5d044d0
8 changed files with 78 additions and 38 deletions

View File

@@ -1492,12 +1492,13 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
// Check against previous transactions
// This is done last to help prevent CPU exhaustion denial-of-service attacks.
if (!CheckInputs(tx, state, view, true, scriptVerifyFlags, true)) {
CachedHashes cachedHashes(tx);
if (!CheckInputs(tx, state, view, true, scriptVerifyFlags, true, cachedHashes)) {
// 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.
if (CheckInputs(tx, state, view, true, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true) &&
!CheckInputs(tx, state, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true)) {
if (CheckInputs(tx, state, view, true, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, cachedHashes) &&
!CheckInputs(tx, state, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, cachedHashes)) {
// Only the witness is wrong, so the transaction itself may be fine.
state.SetCorruptionPossible();
}
@@ -1513,7 +1514,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
// 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))
if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true, cachedHashes))
{
return error("%s: BUG! PLEASE REPORT THIS! ConnectInputs failed against MANDATORY but not STANDARD flags %s, %s",
__func__, hash.ToString(), FormatStateMessage(state));
@@ -1910,7 +1911,7 @@ void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, int nHeight)
bool CScriptCheck::operator()() {
const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
const CScriptWitness *witness = (nIn < ptxTo->wit.vtxinwit.size()) ? &ptxTo->wit.vtxinwit[nIn].scriptWitness : NULL;
if (!VerifyScript(scriptSig, scriptPubKey, witness, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, amount, cacheStore), &error)) {
if (!VerifyScript(scriptSig, scriptPubKey, witness, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, amount, cacheStore, *cachedHashes), &error)) {
return false;
}
return true;
@@ -1969,7 +1970,7 @@ bool CheckTxInputs(const CTransaction& tx, CValidationState& state, const CCoins
}
}// namespace Consensus
bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, std::vector<CScriptCheck> *pvChecks)
bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, CachedHashes& cachedHashes, std::vector<CScriptCheck> *pvChecks)
{
if (!tx.IsCoinBase())
{
@@ -1996,7 +1997,7 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsVi
assert(coins);
// Verify signature
CScriptCheck check(*coins, tx, i, flags, cacheStore);
CScriptCheck check(*coins, tx, i, flags, cacheStore, &cachedHashes);
if (pvChecks) {
pvChecks->push_back(CScriptCheck());
check.swap(pvChecks->back());
@@ -2009,7 +2010,7 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsVi
// avoid splitting the network between upgraded and
// non-upgraded nodes.
CScriptCheck check2(*coins, tx, i,
flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheStore);
flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheStore, &cachedHashes);
if (check2())
return state.Invalid(false, REJECT_NONSTANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check.GetScriptError())));
}
@@ -2405,6 +2406,8 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
std::vector<std::pair<uint256, CDiskTxPos> > vPos;
vPos.reserve(block.vtx.size());
blockundo.vtxundo.reserve(block.vtx.size() - 1);
std::vector<CachedHashes> cachedHashes;
cachedHashes.reserve(block.vtx.size()); // Required so that pointers to individual CachedHashes don't get invalidated
for (unsigned int i = 0; i < block.vtx.size(); i++)
{
const CTransaction &tx = block.vtx[i];
@@ -2451,13 +2454,14 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
return state.DoS(100, error("ConnectBlock(): too many sigops"),
REJECT_INVALID, "bad-blk-sigops");
cachedHashes.emplace_back(tx);
if (!tx.IsCoinBase())
{
nFees += view.GetValueIn(tx)-tx.GetValueOut();
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, nScriptCheckThreads ? &vChecks : NULL))
if (!CheckInputs(tx, state, view, fScriptChecks, flags, fCacheResults, cachedHashes[i], nScriptCheckThreads ? &vChecks : NULL))
return error("ConnectBlock(): CheckInputs on %s failed with %s",
tx.GetHash().ToString(), FormatStateMessage(state));
control.Add(vChecks);