aboutsummaryrefslogtreecommitdiff
path: root/src/policy
diff options
context:
space:
mode:
Diffstat (limited to 'src/policy')
-rw-r--r--src/policy/policy.cpp54
-rw-r--r--src/policy/policy.h12
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;