diff options
Diffstat (limited to 'src/policy')
| -rw-r--r-- | src/policy/policy.cpp | 54 | ||||
| -rw-r--r-- | src/policy/policy.h | 12 |
2 files changed, 65 insertions, 1 deletions
diff --git a/src/policy/policy.cpp b/src/policy/policy.cpp index 48080abc77..ae42b2bd74 100644 --- a/src/policy/policy.cpp +++ b/src/policy/policy.cpp @@ -1,5 +1,5 @@ // Copyright (c) 2009-2010 Satoshi Nakamoto -// Copyright (c) 2009-2015 The Bitcoin developers +// Copyright (c) 2009-2016 The Bitcoin developers // Distributed under the MIT software license, see the accompanying // file COPYING or http://www.opensource.org/licenses/mit-license.php. @@ -154,6 +154,58 @@ bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) return true; } +bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) +{ + if (tx.IsCoinBase()) + return true; // Coinbases are skipped + + for (unsigned int i = 0; i < tx.vin.size(); i++) + { + // We don't care if witness for this input is empty, since it must not be bloated. + // If the script is invalid without witness, it would be caught sooner or later during validation. + if (tx.wit.vtxinwit[i].IsNull()) + continue; + + const CTxOut &prev = mapInputs.GetOutputFor(tx.vin[i]); + + // get the scriptPubKey corresponding to this input: + CScript prevScript = prev.scriptPubKey; + + if (prevScript.IsPayToScriptHash()) { + std::vector <std::vector<unsigned char> > stack; + // If the scriptPubKey is P2SH, we try to extract the redeemScript casually by converting the scriptSig + // into a stack. We do not check IsPushOnly nor compare the hash as these will be done later anyway. + // If the check fails at this stage, we know that this txid must be a bad one. + if (!EvalScript(stack, tx.vin[i].scriptSig, SCRIPT_VERIFY_NONE, BaseSignatureChecker(), SIGVERSION_BASE)) + return false; + if (stack.empty()) + return false; + prevScript = CScript(stack.back().begin(), stack.back().end()); + } + + int witnessversion = 0; + std::vector<unsigned char> witnessprogram; + + // Non-witness program must not be associated with any witness + if (!prevScript.IsWitnessProgram(witnessversion, witnessprogram)) + return false; + + // Check P2WSH standard limits + if (witnessversion == 0 && witnessprogram.size() == 32) { + if (tx.wit.vtxinwit[i].scriptWitness.stack.back().size() > MAX_STANDARD_P2WSH_SCRIPT_SIZE) + return false; + size_t sizeWitnessStack = tx.wit.vtxinwit[i].scriptWitness.stack.size() - 1; + if (sizeWitnessStack > MAX_STANDARD_P2WSH_STACK_ITEMS) + return false; + for (unsigned int j = 0; j < sizeWitnessStack; j++) { + if (tx.wit.vtxinwit[i].scriptWitness.stack[j].size() > MAX_STANDARD_P2WSH_STACK_ITEM_SIZE) + return false; + } + } + } + return true; +} + unsigned int nBytesPerSigOp = DEFAULT_BYTES_PER_SIGOP; int64_t GetVirtualTransactionSize(int64_t nWeight, int64_t nSigOpCost) diff --git a/src/policy/policy.h b/src/policy/policy.h index 9d6ff1233b..fb528d7486 100644 --- a/src/policy/policy.h +++ b/src/policy/policy.h @@ -30,6 +30,12 @@ static const unsigned int MAX_STANDARD_TX_SIGOPS_COST = MAX_BLOCK_SIGOPS_COST/5; static const unsigned int DEFAULT_MAX_MEMPOOL_SIZE = 300; /** Default for -bytespersigop */ static const unsigned int DEFAULT_BYTES_PER_SIGOP = 20; +/** The maximum number of witness stack items in a standard P2WSH script */ +static const unsigned int MAX_STANDARD_P2WSH_STACK_ITEMS = 100; +/** The maximum size of each witness stack item in a standard P2WSH script */ +static const unsigned int MAX_STANDARD_P2WSH_STACK_ITEM_SIZE = 80; +/** The maximum size of a standard witnessScript */ +static const unsigned int MAX_STANDARD_P2WSH_SCRIPT_SIZE = 3600; /** * Standard script verification flags that standard transactions will comply * with. However scripts violating these flags may still be present in valid @@ -69,6 +75,12 @@ bool IsStandardTx(const CTransaction& tx, std::string& reason, const bool witnes * @return True if all inputs (scriptSigs) use only standard transaction forms */ bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs); + /** + * Check if the transaction is over standard P2WSH resources limit: + * 3600bytes witnessScript size, 80bytes per witness stack element, 100 witness stack elements + * These limits are adequate for multi-signature up to n-of-100 using OP_CHECKSIG, OP_ADD, and OP_EQUAL, + */ +bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs); extern unsigned int nBytesPerSigOp; |