From 9b92538adebd30353ffc1a427bc20ab0c3fc75f1 Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Fri, 11 May 2018 13:52:49 -0400 Subject: Remove unused fScriptChecks parameter from CheckInputs fScriptChecks = false just short-circuits the entire function, so passing it in is entirely useless. --- src/test/txvalidationcache_tests.cpp | 20 ++--- src/validation.cpp | 166 +++++++++++++++++------------------ 2 files changed, 91 insertions(+), 95 deletions(-) diff --git a/src/test/txvalidationcache_tests.cpp b/src/test/txvalidationcache_tests.cpp index e69ebcc2c3..193858cca9 100644 --- a/src/test/txvalidationcache_tests.cpp +++ b/src/test/txvalidationcache_tests.cpp @@ -13,7 +13,7 @@ #include -bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, std::vector *pvChecks); +bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, std::vector *pvChecks); BOOST_AUTO_TEST_SUITE(tx_validationcache_tests) @@ -125,7 +125,7 @@ static void ValidateCheckInputsForAllFlags(const CTransaction &tx, uint32_t fail // WITNESS requires P2SH test_flags |= SCRIPT_VERIFY_P2SH; } - bool ret = CheckInputs(tx, state, &::ChainstateActive().CoinsTip(), true, test_flags, true, add_to_cache, txdata, nullptr); + bool ret = CheckInputs(tx, state, &::ChainstateActive().CoinsTip(), test_flags, true, add_to_cache, txdata, nullptr); // CheckInputs should succeed iff test_flags doesn't intersect with // failing_flags bool expected_return_value = !(test_flags & failing_flags); @@ -135,13 +135,13 @@ static void ValidateCheckInputsForAllFlags(const CTransaction &tx, uint32_t fail if (ret && add_to_cache) { // Check that we get a cache hit if the tx was valid std::vector scriptchecks; - BOOST_CHECK(CheckInputs(tx, state, &::ChainstateActive().CoinsTip(), true, test_flags, true, add_to_cache, txdata, &scriptchecks)); + BOOST_CHECK(CheckInputs(tx, state, &::ChainstateActive().CoinsTip(), test_flags, true, add_to_cache, txdata, &scriptchecks)); BOOST_CHECK(scriptchecks.empty()); } else { // Check that we get script executions to check, if the transaction // was invalid, or we didn't add to cache. std::vector scriptchecks; - BOOST_CHECK(CheckInputs(tx, state, &::ChainstateActive().CoinsTip(), true, test_flags, true, add_to_cache, txdata, &scriptchecks)); + BOOST_CHECK(CheckInputs(tx, state, &::ChainstateActive().CoinsTip(), test_flags, true, add_to_cache, txdata, &scriptchecks)); BOOST_CHECK_EQUAL(scriptchecks.size(), tx.vin.size()); } } @@ -204,13 +204,13 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup) CValidationState state; PrecomputedTransactionData ptd_spend_tx(spend_tx); - BOOST_CHECK(!CheckInputs(CTransaction(spend_tx), state, &::ChainstateActive().CoinsTip(), true, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_DERSIG, true, true, ptd_spend_tx, nullptr)); + BOOST_CHECK(!CheckInputs(CTransaction(spend_tx), state, &::ChainstateActive().CoinsTip(), SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_DERSIG, true, true, ptd_spend_tx, nullptr)); // If we call again asking for scriptchecks (as happens in // ConnectBlock), we should add a script check object for this -- we're // not caching invalidity (if that changes, delete this test case). std::vector scriptchecks; - BOOST_CHECK(CheckInputs(CTransaction(spend_tx), state, &::ChainstateActive().CoinsTip(), true, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_DERSIG, true, true, ptd_spend_tx, &scriptchecks)); + BOOST_CHECK(CheckInputs(CTransaction(spend_tx), state, &::ChainstateActive().CoinsTip(), SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_DERSIG, true, true, ptd_spend_tx, &scriptchecks)); BOOST_CHECK_EQUAL(scriptchecks.size(), 1U); // Test that CheckInputs returns true iff DERSIG-enforcing flags are @@ -272,7 +272,7 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup) invalid_with_cltv_tx.vin[0].scriptSig = CScript() << vchSig << 100; CValidationState state; PrecomputedTransactionData txdata(invalid_with_cltv_tx); - BOOST_CHECK(CheckInputs(CTransaction(invalid_with_cltv_tx), state, ::ChainstateActive().CoinsTip(), true, SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY, true, true, txdata, nullptr)); + BOOST_CHECK(CheckInputs(CTransaction(invalid_with_cltv_tx), state, ::ChainstateActive().CoinsTip(), SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY, true, true, txdata, nullptr)); } // TEST CHECKSEQUENCEVERIFY @@ -300,7 +300,7 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup) invalid_with_csv_tx.vin[0].scriptSig = CScript() << vchSig << 100; CValidationState state; PrecomputedTransactionData txdata(invalid_with_csv_tx); - BOOST_CHECK(CheckInputs(CTransaction(invalid_with_csv_tx), state, &::ChainstateActive().CoinsTip(), true, SCRIPT_VERIFY_CHECKSEQUENCEVERIFY, true, true, txdata, nullptr)); + BOOST_CHECK(CheckInputs(CTransaction(invalid_with_csv_tx), state, &::ChainstateActive().CoinsTip(), SCRIPT_VERIFY_CHECKSEQUENCEVERIFY, true, true, txdata, nullptr)); } // TODO: add tests for remaining script flags @@ -362,12 +362,12 @@ BOOST_FIXTURE_TEST_CASE(checkinputs_test, TestChain100Setup) CValidationState state; PrecomputedTransactionData txdata(tx); // This transaction is now invalid under segwit, because of the second input. - BOOST_CHECK(!CheckInputs(CTransaction(tx), state, &::ChainstateActive().CoinsTip(), true, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS, true, true, txdata, nullptr)); + BOOST_CHECK(!CheckInputs(CTransaction(tx), state, &::ChainstateActive().CoinsTip(), SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS, true, true, txdata, nullptr)); std::vector scriptchecks; // Make sure this transaction was not cached (ie because the first // input was valid) - BOOST_CHECK(CheckInputs(CTransaction(tx), state, &::ChainstateActive().CoinsTip(), true, SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS, true, true, txdata, &scriptchecks)); + BOOST_CHECK(CheckInputs(CTransaction(tx), state, &::ChainstateActive().CoinsTip(), SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS, true, true, txdata, &scriptchecks)); // Should get 2 script checks back -- caching is on a whole-transaction basis. BOOST_CHECK_EQUAL(scriptchecks.size(), 2U); } diff --git a/src/validation.cpp b/src/validation.cpp index 74f68a3047..c1646743f6 100644 --- a/src/validation.cpp +++ b/src/validation.cpp @@ -184,7 +184,7 @@ std::unique_ptr pblocktree; // See definition for documentation static void FindFilesToPruneManual(std::set& setFilesToPrune, int nManualPruneHeight); static void FindFilesToPrune(std::set& setFilesToPrune, uint64_t nPruneAfterHeight); -bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, std::vector *pvChecks = nullptr); +bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, std::vector *pvChecks = nullptr); static FILE* OpenUndoFile(const FlatFilePos &pos, bool fReadOnly = false); static FlatFileSeq BlockFileSeq(); static FlatFileSeq UndoFileSeq(); @@ -425,7 +425,7 @@ static bool CheckInputsFromMempoolAndCache(const CTransaction& tx, CValidationSt } } - return CheckInputs(tx, state, view, true, flags, cacheSigStore, true, txdata); + return CheckInputs(tx, state, view, flags, cacheSigStore, true, txdata); } /** @@ -773,15 +773,17 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool constexpr unsigned int scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS; // Check against previous transactions - // This is done last to help prevent CPU exhaustion denial-of-service attacks. + // The first loop above does all the inexpensive checks. + // Only if ALL inputs pass do we perform expensive ECDSA signature checks. + // Helps prevent CPU exhaustion denial-of-service attacks. PrecomputedTransactionData txdata(tx); - if (!CheckInputs(tx, state, view, true, scriptVerifyFlags, true, false, txdata)) { + if (!CheckInputs(tx, state, view, 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, false, txdata) && - !CheckInputs(tx, stateDummy, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, false, txdata)) { + if (!tx.HasWitness() && CheckInputs(tx, stateDummy, view, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, false, txdata) && + !CheckInputs(tx, stateDummy, view, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, false, txdata)) { // Only the witness is missing, so the transaction itself may be fine. state.Invalid(ValidationInvalidReason::TX_WITNESS_MUTATED, false, state.GetRejectCode(), state.GetRejectReason(), state.GetDebugMessage()); @@ -1298,90 +1300,79 @@ void InitScriptExecutionCache() { * * Non-static (and re-declared) in src/test/txvalidationcache_tests.cpp */ -bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, std::vector *pvChecks) EXCLUSIVE_LOCKS_REQUIRED(cs_main) +bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, std::vector *pvChecks) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { - if (!tx.IsCoinBase()) - { - if (pvChecks) - pvChecks->reserve(tx.vin.size()); - - // The first loop above does all the inexpensive checks. - // Only if ALL inputs pass do we perform expensive ECDSA signature checks. - // Helps prevent CPU exhaustion attacks. - - // Skip script verification when connecting blocks under the - // assumevalid block. Assuming the assumevalid block is valid this - // is safe because block merkle hashes are still computed and checked, - // 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); - assert(!coin.IsSpent()); - - // We very carefully only pass in things to CScriptCheck which - // are clearly committed to by tx' witness hash. This provides - // a sanity check that our caching is not introducing consensus - // failures through additional data in, eg, the coins being - // spent being checked as a part of CScriptCheck. - - // Verify signature - CScriptCheck check(coin.out, tx, i, flags, cacheSigStore, &txdata); - if (pvChecks) { - pvChecks->push_back(CScriptCheck()); - check.swap(pvChecks->back()); - } else if (!check()) { - if (flags & STANDARD_NOT_MANDATORY_VERIFY_FLAGS) { - // Check whether the failure was caused by a - // non-mandatory script verification check, such as - // non-standard DER encodings or non-null dummy - // arguments; if so, ensure we return NOT_STANDARD - // instead of CONSENSUS to avoid downstream users - // splitting the network between upgraded and - // non-upgraded nodes by banning CONSENSUS-failing - // data providers. - CScriptCheck check2(coin.out, tx, i, - flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheSigStore, &txdata); - if (check2()) - return state.Invalid(ValidationInvalidReason::TX_NOT_STANDARD, false, REJECT_NONSTANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check.GetScriptError()))); - } - // MANDATORY flag failures correspond to - // ValidationInvalidReason::CONSENSUS. Because CONSENSUS - // failures are the most serious case of validation - // failures, we may need to consider using - // RECENT_CONSENSUS_CHANGE for any script failure that - // could be due to non-upgraded nodes which we may want to - // support, to avoid splitting the network (but this - // depends on the details of how net_processing handles - // such errors). - return state.Invalid(ValidationInvalidReason::CONSENSUS, false, REJECT_INVALID, strprintf("mandatory-script-verify-flag-failed (%s)", ScriptErrorString(check.GetScriptError()))); - } - } + if (tx.IsCoinBase()) return true; + + if (pvChecks) { + pvChecks->reserve(tx.vin.size()); + } + + // 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; + } - if (cacheFullScriptStore && !pvChecks) { - // We executed all of the provided scripts, and were told to - // cache the result. Do so now. - scriptExecutionCache.insert(hashCacheEntry); + for (unsigned int i = 0; i < tx.vin.size(); i++) { + const COutPoint &prevout = tx.vin[i].prevout; + const Coin& coin = inputs.AccessCoin(prevout); + assert(!coin.IsSpent()); + + // We very carefully only pass in things to CScriptCheck which + // are clearly committed to by tx' witness hash. This provides + // a sanity check that our caching is not introducing consensus + // failures through additional data in, eg, the coins being + // spent being checked as a part of CScriptCheck. + + // Verify signature + CScriptCheck check(coin.out, tx, i, flags, cacheSigStore, &txdata); + if (pvChecks) { + pvChecks->push_back(CScriptCheck()); + check.swap(pvChecks->back()); + } else if (!check()) { + if (flags & STANDARD_NOT_MANDATORY_VERIFY_FLAGS) { + // Check whether the failure was caused by a + // non-mandatory script verification check, such as + // non-standard DER encodings or non-null dummy + // arguments; if so, ensure we return NOT_STANDARD + // instead of CONSENSUS to avoid downstream users + // splitting the network between upgraded and + // non-upgraded nodes by banning CONSENSUS-failing + // data providers. + CScriptCheck check2(coin.out, tx, i, + flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheSigStore, &txdata); + if (check2()) + return state.Invalid(ValidationInvalidReason::TX_NOT_STANDARD, false, REJECT_NONSTANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check.GetScriptError()))); } + // MANDATORY flag failures correspond to + // ValidationInvalidReason::CONSENSUS. Because CONSENSUS + // failures are the most serious case of validation + // failures, we may need to consider using + // RECENT_CONSENSUS_CHANGE for any script failure that + // could be due to non-upgraded nodes which we may want to + // support, to avoid splitting the network (but this + // depends on the details of how net_processing handles + // such errors). + return state.Invalid(ValidationInvalidReason::CONSENSUS, 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); + } + return true; } @@ -1769,6 +1760,11 @@ bool CChainState::ConnectBlock(const CBlock& block, CValidationState& state, CBl pindexBestHeader->GetAncestor(pindex->nHeight) == pindex && pindexBestHeader->nChainWork >= nMinimumChainWork) { // This block is a member of the assumed verified chain and an ancestor of the best header. + // Script verification is skipped when connecting blocks under the + // assumevalid block. Assuming the assumevalid block is valid this + // is safe because block merkle hashes are still computed and checked, + // Of course, if an assumed valid block is invalid due to false scriptSigs + // this optimization would allow an invalid chain to be accepted. // The equivalent time check discourages hash power from extorting the network via DOS attack // into accepting an invalid block through telling users they must manually set assumevalid. // Requiring a software change or burying the invalid block, regardless of the setting, makes @@ -1952,7 +1948,7 @@ bool CChainState::ConnectBlock(const CBlock& block, CValidationState& state, CBl { std::vector 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, fCacheResults, txdata[i], nScriptCheckThreads ? &vChecks : nullptr)) { + if (fScriptChecks && !CheckInputs(tx, state, view, flags, fCacheResults, fCacheResults, txdata[i], nScriptCheckThreads ? &vChecks : nullptr)) { if (state.GetReason() == ValidationInvalidReason::TX_NOT_STANDARD) { // CheckInputs may return NOT_STANDARD for extra flags we passed, // but we can't return that, as it's not defined for a block, so -- cgit v1.2.3