From 9238ecb41752e097443d0bc117df35ebd4ac932e Mon Sep 17 00:00:00 2001 From: Luke Dashjr Date: Sat, 11 Oct 2014 22:41:05 +0000 Subject: [PATCH] Policy: MOVEONLY: 3 functions to policy.o: - [script/standard.o] IsStandard - [main.o] IsStandardTx - [main.o] AreInputsStandard Also, don't use namespace std in policy.cpp --- src/Makefile.am | 1 + src/main.cpp | 138 ------------------------- src/main.h | 24 ----- src/policy/policy.cpp | 178 +++++++++++++++++++++++++++++++++ src/policy/policy.h | 17 ++++ src/script/standard.cpp | 20 ---- src/script/standard.h | 1 - src/test/multisig_tests.cpp | 2 +- src/test/transaction_tests.cpp | 1 + 9 files changed, 198 insertions(+), 184 deletions(-) create mode 100644 src/policy/policy.cpp diff --git a/src/Makefile.am b/src/Makefile.am index 5515b2f18..b82c6dc37 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -177,6 +177,7 @@ libbitcoin_server_a_SOURCES = \ net.cpp \ noui.cpp \ policy/fees.cpp \ + policy/policy.cpp \ pow.cpp \ rest.cpp \ rpcblockchain.cpp \ diff --git a/src/main.cpp b/src/main.cpp index 05130f308..f966f6869 100644 --- a/src/main.cpp +++ b/src/main.cpp @@ -606,76 +606,6 @@ unsigned int LimitOrphanTxSize(unsigned int nMaxOrphans) return nEvicted; } - - - - - - -bool IsStandardTx(const CTransaction& tx, string& reason) -{ - if (tx.nVersion > CTransaction::CURRENT_VERSION || tx.nVersion < 1) { - reason = "version"; - return false; - } - - // Extremely large transactions with lots of inputs can cost the network - // almost as much to process as they cost the sender in fees, because - // computing signature hashes is O(ninputs*txsize). Limiting transactions - // to MAX_STANDARD_TX_SIZE mitigates CPU exhaustion attacks. - unsigned int sz = tx.GetSerializeSize(SER_NETWORK, CTransaction::CURRENT_VERSION); - if (sz >= MAX_STANDARD_TX_SIZE) { - reason = "tx-size"; - return false; - } - - BOOST_FOREACH(const CTxIn& txin, tx.vin) - { - // Biggest 'standard' txin is a 15-of-15 P2SH multisig with compressed - // keys. (remember the 520 byte limit on redeemScript size) That works - // out to a (15*(33+1))+3=513 byte redeemScript, 513+1+15*(73+1)+3=1627 - // bytes of scriptSig, which we round off to 1650 bytes for some minor - // future-proofing. That's also enough to spend a 20-of-20 - // CHECKMULTISIG scriptPubKey, though such a scriptPubKey is not - // considered standard) - if (txin.scriptSig.size() > 1650) { - reason = "scriptsig-size"; - return false; - } - if (!txin.scriptSig.IsPushOnly()) { - reason = "scriptsig-not-pushonly"; - return false; - } - } - - unsigned int nDataOut = 0; - txnouttype whichType; - BOOST_FOREACH(const CTxOut& txout, tx.vout) { - if (!::IsStandard(txout.scriptPubKey, whichType)) { - reason = "scriptpubkey"; - return false; - } - - if (whichType == TX_NULL_DATA) - nDataOut++; - else if ((whichType == TX_MULTISIG) && (!fIsBareMultisigStd)) { - reason = "bare-multisig"; - return false; - } else if (txout.IsDust(::minRelayTxFee)) { - reason = "dust"; - return false; - } - } - - // only one OP_RETURN txout is permitted - if (nDataOut > 1) { - reason = "multi-op-return"; - return false; - } - - return true; -} - bool IsFinalTx(const CTransaction &tx, int nBlockHeight, int64_t nBlockTime) { if (tx.nLockTime == 0) @@ -694,74 +624,6 @@ bool CheckFinalTx(const CTransaction &tx) return IsFinalTx(tx, chainActive.Height() + 1, GetAdjustedTime()); } -/** - * Check transaction inputs to mitigate two - * potential denial-of-service attacks: - * - * 1. scriptSigs with extra data stuffed into them, - * not consumed by scriptPubKey (or P2SH script) - * 2. P2SH scripts with a crazy number of expensive - * CHECKSIG/CHECKMULTISIG operations - */ -bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) -{ - if (tx.IsCoinBase()) - return true; // Coinbases don't use vin normally - - for (unsigned int i = 0; i < tx.vin.size(); i++) - { - const CTxOut& prev = mapInputs.GetOutputFor(tx.vin[i]); - - vector > vSolutions; - txnouttype whichType; - // get the scriptPubKey corresponding to this input: - const CScript& prevScript = prev.scriptPubKey; - if (!Solver(prevScript, whichType, vSolutions)) - return false; - int nArgsExpected = ScriptSigArgsExpected(whichType, vSolutions); - if (nArgsExpected < 0) - return false; - - // Transactions with extra stuff in their scriptSigs are - // non-standard. Note that this EvalScript() call will - // be quick, because if there are any operations - // beside "push data" in the scriptSig - // IsStandardTx() will have already returned false - // and this method isn't called. - vector > stack; - if (!EvalScript(stack, tx.vin[i].scriptSig, SCRIPT_VERIFY_NONE, BaseSignatureChecker())) - return false; - - if (whichType == TX_SCRIPTHASH) - { - if (stack.empty()) - return false; - CScript subscript(stack.back().begin(), stack.back().end()); - vector > vSolutions2; - txnouttype whichType2; - if (Solver(subscript, whichType2, vSolutions2)) - { - int tmpExpected = ScriptSigArgsExpected(whichType2, vSolutions2); - if (tmpExpected < 0) - return false; - nArgsExpected += tmpExpected; - } - else - { - // Any other Script with less than 15 sigops OK: - unsigned int sigops = subscript.GetSigOpCount(true); - // ... extra data left on the stack after execution is OK, too: - return (sigops <= MAX_P2SH_SIGOPS); - } - } - - if (stack.size() != (unsigned int)nArgsExpected) - return false; - } - - return true; -} - unsigned int GetLegacySigOpCount(const CTransaction& tx) { unsigned int nSigOps = 0; diff --git a/src/main.h b/src/main.h index 85a144642..8f72a955a 100644 --- a/src/main.h +++ b/src/main.h @@ -261,25 +261,6 @@ struct CDiskTxPos : public CDiskBlockPos CAmount GetMinRelayFee(const CTransaction& tx, unsigned int nBytes, bool fAllowFree); -/** - * Check transaction inputs, and make sure any - * pay-to-script-hash transactions are evaluating IsStandard scripts - * - * Why bother? To avoid denial-of-service attacks; an attacker - * can submit a standard HASH... OP_EQUAL transaction, - * which will get accepted into blocks. The redemption - * script can be anything; an attacker could use a very - * expensive-to-check-upon-redemption script like: - * DUP CHECKSIG DROP ... repeated 100 times... OP_1 - */ - -/** - * Check for standard transaction types - * @param[in] mapInputs Map of previous transactions that have outputs we're spending - * @return True if all inputs (scriptSigs) use only standard transaction forms - */ -bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs); - /** * Count ECDSA signature operations the old-fashioned (pre-0.6) way * @return number of sigops this transaction's outputs will produce when spent @@ -311,11 +292,6 @@ void UpdateCoins(const CTransaction& tx, CValidationState &state, CCoinsViewCach /** Context-independent validity checks */ bool CheckTransaction(const CTransaction& tx, CValidationState& state); -/** Check for standard transaction types - * @return True if all outputs (scriptPubKeys) use only standard transaction forms - */ -bool IsStandardTx(const CTransaction& tx, std::string& reason); - /** * Check if transaction is final and can be included in a block with the * specified height and time. Consensus critical. diff --git a/src/policy/policy.cpp b/src/policy/policy.cpp new file mode 100644 index 000000000..169fef4af --- /dev/null +++ b/src/policy/policy.cpp @@ -0,0 +1,178 @@ +// Copyright (c) 2009-2010 Satoshi Nakamoto +// Copyright (c) 2009-2014 The Bitcoin developers +// Distributed under the MIT software license, see the accompanying +// file COPYING or http://www.opensource.org/licenses/mit-license.php. + +// NOTE: This file is intended to be customised by the end user, and includes only local node policy logic + +#include "policy/policy.h" + +#include "main.h" +#include "tinyformat.h" +#include "util.h" +#include "utilstrencodings.h" + +#include + + /** + * Check transaction inputs to mitigate two + * potential denial-of-service attacks: + * + * 1. scriptSigs with extra data stuffed into them, + * not consumed by scriptPubKey (or P2SH script) + * 2. P2SH scripts with a crazy number of expensive + * CHECKSIG/CHECKMULTISIG operations + * + * Check transaction inputs, and make sure any + * pay-to-script-hash transactions are evaluating IsStandard scripts + * + * Why bother? To avoid denial-of-service attacks; an attacker + * can submit a standard HASH... OP_EQUAL transaction, + * which will get accepted into blocks. The redemption + * script can be anything; an attacker could use a very + * expensive-to-check-upon-redemption script like: + * DUP CHECKSIG DROP ... repeated 100 times... OP_1 + */ + +bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType) +{ + std::vector > vSolutions; + if (!Solver(scriptPubKey, whichType, vSolutions)) + return false; + + if (whichType == TX_MULTISIG) + { + unsigned char m = vSolutions.front()[0]; + unsigned char n = vSolutions.back()[0]; + // Support up to x-of-3 multisig txns as standard + if (n < 1 || n > 3) + return false; + if (m < 1 || m > n) + return false; + } + + return whichType != TX_NONSTANDARD; +} + +bool IsStandardTx(const CTransaction& tx, std::string& reason) +{ + if (tx.nVersion > CTransaction::CURRENT_VERSION || tx.nVersion < 1) { + reason = "version"; + return false; + } + + // Extremely large transactions with lots of inputs can cost the network + // almost as much to process as they cost the sender in fees, because + // computing signature hashes is O(ninputs*txsize). Limiting transactions + // to MAX_STANDARD_TX_SIZE mitigates CPU exhaustion attacks. + unsigned int sz = tx.GetSerializeSize(SER_NETWORK, CTransaction::CURRENT_VERSION); + if (sz >= MAX_STANDARD_TX_SIZE) { + reason = "tx-size"; + return false; + } + + BOOST_FOREACH(const CTxIn& txin, tx.vin) + { + // Biggest 'standard' txin is a 15-of-15 P2SH multisig with compressed + // keys. (remember the 520 byte limit on redeemScript size) That works + // out to a (15*(33+1))+3=513 byte redeemScript, 513+1+15*(73+1)+3=1627 + // bytes of scriptSig, which we round off to 1650 bytes for some minor + // future-proofing. That's also enough to spend a 20-of-20 + // CHECKMULTISIG scriptPubKey, though such a scriptPubKey is not + // considered standard) + if (txin.scriptSig.size() > 1650) { + reason = "scriptsig-size"; + return false; + } + if (!txin.scriptSig.IsPushOnly()) { + reason = "scriptsig-not-pushonly"; + return false; + } + } + + unsigned int nDataOut = 0; + txnouttype whichType; + BOOST_FOREACH(const CTxOut& txout, tx.vout) { + if (!::IsStandard(txout.scriptPubKey, whichType)) { + reason = "scriptpubkey"; + return false; + } + + if (whichType == TX_NULL_DATA) + nDataOut++; + else if ((whichType == TX_MULTISIG) && (!fIsBareMultisigStd)) { + reason = "bare-multisig"; + return false; + } else if (txout.IsDust(::minRelayTxFee)) { + reason = "dust"; + return false; + } + } + + // only one OP_RETURN txout is permitted + if (nDataOut > 1) { + reason = "multi-op-return"; + return false; + } + + return true; +} + +bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) +{ + if (tx.IsCoinBase()) + return true; // Coinbases don't use vin normally + + for (unsigned int i = 0; i < tx.vin.size(); i++) + { + const CTxOut& prev = mapInputs.GetOutputFor(tx.vin[i]); + + std::vector > vSolutions; + txnouttype whichType; + // get the scriptPubKey corresponding to this input: + const CScript& prevScript = prev.scriptPubKey; + if (!Solver(prevScript, whichType, vSolutions)) + return false; + int nArgsExpected = ScriptSigArgsExpected(whichType, vSolutions); + if (nArgsExpected < 0) + return false; + + // Transactions with extra stuff in their scriptSigs are + // non-standard. Note that this EvalScript() call will + // be quick, because if there are any operations + // beside "push data" in the scriptSig + // IsStandardTx() will have already returned false + // and this method isn't called. + std::vector > stack; + if (!EvalScript(stack, tx.vin[i].scriptSig, SCRIPT_VERIFY_NONE, BaseSignatureChecker())) + return false; + + if (whichType == TX_SCRIPTHASH) + { + if (stack.empty()) + return false; + CScript subscript(stack.back().begin(), stack.back().end()); + std::vector > vSolutions2; + txnouttype whichType2; + if (Solver(subscript, whichType2, vSolutions2)) + { + int tmpExpected = ScriptSigArgsExpected(whichType2, vSolutions2); + if (tmpExpected < 0) + return false; + nArgsExpected += tmpExpected; + } + else + { + // Any other Script with less than 15 sigops OK: + unsigned int sigops = subscript.GetSigOpCount(true); + // ... extra data left on the stack after execution is OK, too: + return (sigops <= MAX_P2SH_SIGOPS); + } + } + + if (stack.size() != (unsigned int)nArgsExpected) + return false; + } + + return true; +} diff --git a/src/policy/policy.h b/src/policy/policy.h index 48e192d55..1551aecde 100644 --- a/src/policy/policy.h +++ b/src/policy/policy.h @@ -10,6 +10,10 @@ #include "script/interpreter.h" #include "script/standard.h" +#include + +class CCoinsViewCache; + /** Default for -blockmaxsize and -blockminsize, which control the range of sizes the mining code will create **/ static const unsigned int DEFAULT_BLOCK_MAX_SIZE = 750000; static const unsigned int DEFAULT_BLOCK_MIN_SIZE = 0; @@ -38,4 +42,17 @@ static const unsigned int STANDARD_SCRIPT_VERIFY_FLAGS = MANDATORY_SCRIPT_VERIFY /** For convenience, standard but not mandatory verify flags. */ static const unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS = STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS; +bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType); + /** + * Check for standard transaction types + * @return True if all outputs (scriptPubKeys) use only standard transaction forms + */ +bool IsStandardTx(const CTransaction& tx, std::string& reason); + /** + * Check for standard transaction types + * @param[in] mapInputs Map of previous transactions that have outputs we're spending + * @return True if all inputs (scriptSigs) use only standard transaction forms + */ +bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs); + #endif // BITCOIN_POLICY_H diff --git a/src/script/standard.cpp b/src/script/standard.cpp index ce50e3aad..66657127a 100644 --- a/src/script/standard.cpp +++ b/src/script/standard.cpp @@ -180,26 +180,6 @@ int ScriptSigArgsExpected(txnouttype t, const std::vector vSolutions; - if (!Solver(scriptPubKey, whichType, vSolutions)) - return false; - - if (whichType == TX_MULTISIG) - { - unsigned char m = vSolutions.front()[0]; - unsigned char n = vSolutions.back()[0]; - // Support up to x-of-3 multisig txns as standard - if (n < 1 || n > 3) - return false; - if (m < 1 || m > n) - return false; - } - - return whichType != TX_NONSTANDARD; -} - bool ExtractDestination(const CScript& scriptPubKey, CTxDestination& addressRet) { vector vSolutions; diff --git a/src/script/standard.h b/src/script/standard.h index c4ad17dd8..46ae5f9f1 100644 --- a/src/script/standard.h +++ b/src/script/standard.h @@ -69,7 +69,6 @@ const char* GetTxnOutputType(txnouttype t); bool Solver(const CScript& scriptPubKey, txnouttype& typeRet, std::vector >& vSolutionsRet); int ScriptSigArgsExpected(txnouttype t, const std::vector >& vSolutions); -bool IsStandard(const CScript& scriptPubKey, txnouttype& whichType); bool ExtractDestination(const CScript& scriptPubKey, CTxDestination& addressRet); bool ExtractDestinations(const CScript& scriptPubKey, txnouttype& typeRet, std::vector& addressRet, int& nRequiredRet); diff --git a/src/test/multisig_tests.cpp b/src/test/multisig_tests.cpp index 6b189a6b5..b65c299ad 100644 --- a/src/test/multisig_tests.cpp +++ b/src/test/multisig_tests.cpp @@ -4,7 +4,7 @@ #include "key.h" #include "keystore.h" -#include "main.h" +#include "policy/policy.h" #include "script/script.h" #include "script/script_error.h" #include "script/interpreter.h" diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp index 9ce7aae96..260524f7c 100644 --- a/src/test/transaction_tests.cpp +++ b/src/test/transaction_tests.cpp @@ -12,6 +12,7 @@ #include "key.h" #include "keystore.h" #include "main.h" +#include "policy/policy.h" #include "script/script.h" #include "script/script_error.h"