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-rwxr-xr-xqa/rpc-tests/p2p-segwit.py111
-rw-r--r--src/main.cpp6
-rw-r--r--src/policy/policy.cpp54
-rw-r--r--src/policy/policy.h12
4 files changed, 181 insertions, 2 deletions
diff --git a/qa/rpc-tests/p2p-segwit.py b/qa/rpc-tests/p2p-segwit.py
index c2ea20bb84..16d1e86802 100755
--- a/qa/rpc-tests/p2p-segwit.py
+++ b/qa/rpc-tests/p2p-segwit.py
@@ -1706,6 +1706,116 @@ class SegWitTest(BitcoinTestFramework):
assert(block_version & (1 << VB_WITNESS_BIT) != 0)
self.nodes[0].setmocktime(0) # undo mocktime
+ def test_non_standard_witness(self):
+ print("\tTesting detection of non-standard P2WSH witness")
+ pad = chr(1).encode('latin-1')
+
+ # Create scripts for tests
+ scripts = []
+ scripts.append(CScript([OP_DROP] * 100))
+ scripts.append(CScript([OP_DROP] * 99))
+ scripts.append(CScript([pad * 59] * 59 + [OP_DROP] * 60))
+ scripts.append(CScript([pad * 59] * 59 + [OP_DROP] * 61))
+
+ p2wsh_scripts = []
+
+ assert(len(self.utxo))
+ tx = CTransaction()
+ tx.vin.append(CTxIn(COutPoint(self.utxo[0].sha256, self.utxo[0].n), b""))
+
+ # For each script, generate a pair of P2WSH and P2SH-P2WSH output.
+ outputvalue = (self.utxo[0].nValue - 1000) // (len(scripts) * 2)
+ for i in scripts:
+ p2wsh = CScript([OP_0, sha256(i)])
+ p2sh = hash160(p2wsh)
+ p2wsh_scripts.append(p2wsh)
+ tx.vout.append(CTxOut(outputvalue, p2wsh))
+ tx.vout.append(CTxOut(outputvalue, CScript([OP_HASH160, p2sh, OP_EQUAL])))
+ tx.rehash()
+ txid = tx.sha256
+ self.test_node.test_transaction_acceptance(tx, with_witness=False, accepted=True)
+
+ self.nodes[0].generate(1)
+ sync_blocks(self.nodes)
+
+ # Creating transactions for tests
+ p2wsh_txs = []
+ p2sh_txs = []
+ for i in range(len(scripts)):
+ p2wsh_tx = CTransaction()
+ p2wsh_tx.vin.append(CTxIn(COutPoint(txid,i*2)))
+ p2wsh_tx.vout.append(CTxOut(outputvalue - 5000, CScript([OP_0, hash160(hex_str_to_bytes(""))])))
+ p2wsh_tx.wit.vtxinwit.append(CTxInWitness())
+ p2wsh_tx.rehash()
+ p2wsh_txs.append(p2wsh_tx)
+ p2sh_tx = CTransaction()
+ p2sh_tx.vin.append(CTxIn(COutPoint(txid,i*2+1), CScript([p2wsh_scripts[i]])))
+ p2sh_tx.vout.append(CTxOut(outputvalue - 5000, CScript([OP_0, hash160(hex_str_to_bytes(""))])))
+ p2sh_tx.wit.vtxinwit.append(CTxInWitness())
+ p2sh_tx.rehash()
+ p2sh_txs.append(p2sh_tx)
+
+ # Testing native P2WSH
+ # Witness stack size, excluding witnessScript, over 100 is non-standard
+ p2wsh_txs[0].wit.vtxinwit[0].scriptWitness.stack = [pad] * 101 + [scripts[0]]
+ self.std_node.test_transaction_acceptance(p2wsh_txs[0], True, False, b'bad-witness-nonstandard')
+ # Non-standard nodes should accept
+ self.test_node.test_transaction_acceptance(p2wsh_txs[0], True, True)
+
+ # Stack element size over 80 bytes is non-standard
+ p2wsh_txs[1].wit.vtxinwit[0].scriptWitness.stack = [pad * 81] * 100 + [scripts[1]]
+ # It can't be used to blind a node to the transaction
+ self.std_node.announce_tx_and_wait_for_getdata(p2wsh_txs[1])
+ self.std_node.test_transaction_acceptance(p2wsh_txs[1], True, False, b'bad-witness-nonstandard')
+ self.std_node.announce_tx_and_wait_for_getdata(p2wsh_txs[1])
+ self.std_node.test_transaction_acceptance(p2wsh_txs[1], True, False, b'bad-witness-nonstandard')
+ # Non-standard nodes should accept
+ self.test_node.test_transaction_acceptance(p2wsh_txs[1], True, True)
+ # Standard nodes should accept if element size is not over 80 bytes
+ p2wsh_txs[1].wit.vtxinwit[0].scriptWitness.stack = [pad * 80] * 100 + [scripts[1]]
+ self.std_node.announce_tx_and_wait_for_getdata(p2wsh_txs[1])
+ self.std_node.test_transaction_acceptance(p2wsh_txs[1], True, True)
+
+ # witnessScript size at 3600 bytes is standard
+ p2wsh_txs[2].wit.vtxinwit[0].scriptWitness.stack = [pad, pad, scripts[2]]
+ self.test_node.test_transaction_acceptance(p2wsh_txs[2], True, True)
+ self.std_node.test_transaction_acceptance(p2wsh_txs[2], True, True)
+
+ # witnessScript size at 3601 bytes is non-standard
+ p2wsh_txs[3].wit.vtxinwit[0].scriptWitness.stack = [pad, pad, pad, scripts[3]]
+ self.std_node.test_transaction_acceptance(p2wsh_txs[3], True, False, b'bad-witness-nonstandard')
+ # Non-standard nodes should accept
+ self.test_node.test_transaction_acceptance(p2wsh_txs[3], True, True)
+
+ # Repeating the same tests with P2SH-P2WSH
+ p2sh_txs[0].wit.vtxinwit[0].scriptWitness.stack = [pad] * 101 + [scripts[0]]
+ self.std_node.test_transaction_acceptance(p2sh_txs[0], True, False, b'bad-witness-nonstandard')
+ self.test_node.test_transaction_acceptance(p2sh_txs[0], True, True)
+ p2sh_txs[1].wit.vtxinwit[0].scriptWitness.stack = [pad * 81] * 100 + [scripts[1]]
+ self.std_node.announce_tx_and_wait_for_getdata(p2sh_txs[1])
+ self.std_node.test_transaction_acceptance(p2sh_txs[1], True, False, b'bad-witness-nonstandard')
+ self.std_node.announce_tx_and_wait_for_getdata(p2sh_txs[1])
+ self.std_node.test_transaction_acceptance(p2sh_txs[1], True, False, b'bad-witness-nonstandard')
+ self.test_node.test_transaction_acceptance(p2sh_txs[1], True, True)
+ p2sh_txs[1].wit.vtxinwit[0].scriptWitness.stack = [pad * 80] * 100 + [scripts[1]]
+ self.std_node.announce_tx_and_wait_for_getdata(p2sh_txs[1])
+ self.std_node.test_transaction_acceptance(p2sh_txs[1], True, True)
+ p2sh_txs[2].wit.vtxinwit[0].scriptWitness.stack = [pad, pad, scripts[2]]
+ self.test_node.test_transaction_acceptance(p2sh_txs[2], True, True)
+ self.std_node.test_transaction_acceptance(p2sh_txs[2], True, True)
+ p2sh_txs[3].wit.vtxinwit[0].scriptWitness.stack = [pad, pad, pad, scripts[3]]
+ self.std_node.test_transaction_acceptance(p2sh_txs[3], True, False, b'bad-witness-nonstandard')
+ self.test_node.test_transaction_acceptance(p2sh_txs[3], True, True)
+
+ self.nodes[0].generate(1) # Mine and clean up the mempool of non-standard node
+ # Valid but non-standard transactions in a block should be accepted by standard node
+ sync_blocks(self.nodes)
+ assert_equal(len(self.nodes[0].getrawmempool()), 0)
+ assert_equal(len(self.nodes[1].getrawmempool()), 0)
+
+ self.utxo.pop(0)
+
+
def run_test(self):
# Setup the p2p connections and start up the network thread.
self.test_node = TestNode() # sets NODE_WITNESS|NODE_NETWORK
@@ -1778,6 +1888,7 @@ class SegWitTest(BitcoinTestFramework):
self.test_segwit_versions()
self.test_premature_coinbase_witness_spend()
self.test_signature_version_1()
+ self.test_non_standard_witness()
sync_blocks(self.nodes)
if self.test_upgrade:
self.test_upgrade_after_activation(self.nodes[2], 2)
diff --git a/src/main.cpp b/src/main.cpp
index c92a38be98..020378b5dc 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,5 +1,5 @@
// Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2015 The Bitcoin Core developers
+// Copyright (c) 2009-2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
@@ -1273,6 +1273,10 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
if (fRequireStandard && !AreInputsStandard(tx, view))
return state.Invalid(false, REJECT_NONSTANDARD, "bad-txns-nonstandard-inputs");
+ // Check for non-standard witness in P2WSH
+ if (!tx.wit.IsNull() && fRequireStandard && !IsWitnessStandard(tx, view))
+ return state.DoS(0, false, REJECT_NONSTANDARD, "bad-witness-nonstandard", true);
+
int64_t nSigOpsCost = GetTransactionSigOpCost(tx, view, STANDARD_SCRIPT_VERIFY_FLAGS);
CAmount nValueOut = tx.GetValueOut();
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;