Merge 7c35312964 into 51d76634fb

src/init.cpp

@@ -641,6 +641,7 @@ void SetupServerArgs(ArgsManager& argsman, bool can_listen_ipc)
                              "is of this size or less (default: %u)",
                              MAX_OP_RETURN_RELAY),
                    ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
+    argsman.AddArg("-limitdummyscriptdatasize", strprintf("Maximum size of dummy script data we relay and mine (default: %u)", MAX_DUMMY_SCRIPT_RELAY), ArgsManager::ALLOW_ANY, OptionsCategory::NODE_RELAY);
     argsman.AddArg("-permitbaremultisig", strprintf("Relay transactions creating non-P2SH multisig outputs (default: %u)", DEFAULT_PERMIT_BAREMULTISIG), ArgsManager::ALLOW_ANY,
                    OptionsCategory::NODE_RELAY);
     argsman.AddArg("-minrelaytxfee=<amt>", strprintf("Fees (in %s/kvB) smaller than this are considered zero fee for relaying, mining and transaction creation (default: %s)",

src/kernel/mempool_options.h

@@ -51,6 +51,7 @@ struct MemPoolOptions {
      * If nullopt, any size is nonstandard.
      */
     std::optional<unsigned> max_datacarrier_bytes{DEFAULT_ACCEPT_DATACARRIER ? std::optional{MAX_OP_RETURN_RELAY} : std::nullopt};
+    unsigned int max_dummy_script_bytes{MAX_DUMMY_SCRIPT_RELAY};
     bool permit_bare_multisig{DEFAULT_PERMIT_BAREMULTISIG};
     bool require_standard{true};
     bool persist_v1_dat{DEFAULT_PERSIST_V1_DAT};

src/node/mempool_args.cpp

@@ -87,6 +87,8 @@ util::Result<void> ApplyArgsManOptions(const ArgsManager& argsman, const CChainP
         mempool_opts.max_datacarrier_bytes = std::nullopt;
     }
 
+    mempool_opts.max_dummy_script_bytes = argsman.GetIntArg("-limitdummyscriptdatasize", MAX_DUMMY_SCRIPT_RELAY);
+
     mempool_opts.require_standard = !argsman.GetBoolArg("-acceptnonstdtxn", DEFAULT_ACCEPT_NON_STD_TXN);
     if (!chainparams.IsTestChain() && !mempool_opts.require_standard) {
         return util::Error{Untranslated(strprintf("acceptnonstdtxn is not currently supported for %s chain", chainparams.GetChainTypeString()))};

src/policy/policy.cpp

@@ -321,3 +321,66 @@ int64_t GetVirtualTransactionInputSize(const CTxIn& txin, int64_t nSigOpCost, un
 {
     return GetVirtualTransactionSize(GetTransactionInputWeight(txin), nSigOpCost, bytes_per_sigop);
 }
+
+std::pair<CScript, unsigned int> GetScriptForTransactionInput(CScript prev_script, const CTxIn& txin)
+{
+    bool p2sh = false;
+    if (prev_script.IsPayToScriptHash()) {
+        std::vector <std::vector<unsigned char> > stack;
+        if (!EvalScript(stack, txin.scriptSig, SCRIPT_VERIFY_NONE, BaseSignatureChecker(), SigVersion::BASE)) {
+            return std::make_pair(CScript(), 0);
+        }
+        if (stack.empty()) {
+            return std::make_pair(CScript(), 0);
+        }
+        prev_script = CScript(stack.back().begin(), stack.back().end());
+        p2sh = true;
+    }
+
+    int witnessversion = 0;
+    std::vector<unsigned char> witnessprogram;
+
+    if (!prev_script.IsWitnessProgram(witnessversion, witnessprogram)) {
+        // For P2SH, scriptSig is always push-only, so the actual script is only the last stack item
+        // For non-P2SH, prevScript is likely the real script, but not part of this transaction, and scriptSig could very well be executable, so return the latter instead
+        return std::make_pair(p2sh ? prev_script : txin.scriptSig, WITNESS_SCALE_FACTOR);
+    }
+
+    auto stack = std::span{txin.scriptWitness.stack};
+
+    if (witnessversion == 0 && witnessprogram.size() == WITNESS_V0_SCRIPTHASH_SIZE) {
+        if (stack.empty()) return std::make_pair(CScript(), 0);  // invalid
+        auto& script_data = stack.back();
+        prev_script = CScript(script_data.begin(), script_data.end());
+        return std::make_pair(prev_script, 1);
+    }
+
+    if (witnessversion == 1 && witnessprogram.size() == WITNESS_V1_TAPROOT_SIZE && !p2sh) {
+        if (stack.size() >= 2 && !stack.back().empty() && stack.back()[0] == ANNEX_TAG) {
+            SpanPopBack(stack);
+        }
+        if (stack.size() >= 2) {
+            SpanPopBack(stack);  // Ignore control block
+            prev_script = CScript(stack.back().begin(), stack.back().end());
+            return std::make_pair(prev_script, 1);
+        }
+    }
+
+    return std::make_pair(CScript(), 0);
+}
+
+size_t DummyScriptBytes(const CTransaction& tx, const CCoinsViewCache& view)
+{
+    size_t ret{0};
+
+    for (const CTxIn& txin : tx.vin) {
+        const CTxOut &utxo = view.AccessCoin(txin.prevout).out;
+        auto[script, consensus_weight_per_byte] = GetScriptForTransactionInput(utxo.scriptPubKey, txin);
+        ret += script.DummyScriptBytes();
+    }
+    for (const CTxOut& txout : tx.vout) {
+        ret += txout.scriptPubKey.DummyScriptBytes();
+    }
+
+    return ret;
+}

src/policy/policy.h

@@ -14,6 +14,7 @@
 
 #include <cstdint>
 #include <string>
+#include <utility>
 
 class CCoinsViewCache;
 class CFeeRate;
@@ -72,6 +73,8 @@ static constexpr unsigned int DEFAULT_DESCENDANT_LIMIT{25};
 static constexpr unsigned int DEFAULT_DESCENDANT_SIZE_LIMIT_KVB{101};
 /** Default for -datacarrier */
 static const bool DEFAULT_ACCEPT_DATACARRIER = true;
+/** Default setting for -limitdummyscriptdatasize */
+static const unsigned int MAX_DUMMY_SCRIPT_RELAY{0};
 /**
  * Default setting for -datacarriersize. 80 bytes of data, +1 for OP_RETURN,
  * +2 for the pushdata opcodes.
@@ -181,4 +184,8 @@ static inline int64_t GetVirtualTransactionInputSize(const CTxIn& tx)
     return GetVirtualTransactionInputSize(tx, 0, 0);
 }
 
+std::pair<CScript, unsigned int> GetScriptForTransactionInput(CScript prev_script, const CTxIn&);
+
+size_t DummyScriptBytes(const CTransaction& tx, const CCoinsViewCache& view);
+
 #endif // BITCOIN_POLICY_POLICY_H

src/script/script.cpp

@@ -303,6 +303,53 @@ bool CScript::HasValidOps() const
     return true;
 }
 
+size_t CScript::DummyScriptBytes() const
+{
+    size_t counted{0};
+    opcodetype opcode, last_opcode{OP_INVALIDOPCODE};
+    std::vector<unsigned char> push_data;
+    unsigned int inside_noop{0}, inside_conditional{0};
+    CScript::const_iterator opcode_it = begin(), data_began = begin();
+    for (CScript::const_iterator it = begin(); it < end(); last_opcode = opcode) {
+        opcode_it = it;
+        if (!GetOp(it, opcode, push_data)) {
+            // Invalid scripts are necessarily all data
+            return size();
+        }
+
+        if (opcode == OP_IF || opcode == OP_NOTIF) {
+            ++inside_conditional;
+        } else if (opcode == OP_ENDIF) {
+            if (!inside_conditional) return size();  // invalid
+            --inside_conditional;
+        }
+
+        // Match OP_FALSE OP_IF
+        if (inside_noop) {
+            switch (opcode) {
+            case OP_IF: case OP_NOTIF:
+                ++inside_noop;
+                break;
+            case OP_ENDIF:
+                if (0 == --inside_noop) {
+                    counted += it - data_began + 1;
+                }
+                break;
+            default: /* do nothing */;
+            }
+        } else if (opcode == OP_IF && last_opcode == OP_FALSE) {
+            inside_noop = 1;
+            data_began = opcode_it;
+        // Match <data> OP_DROP
+        } else if (opcode <= OP_PUSHDATA4) {
+            data_began = opcode_it;
+        } else if (opcode == OP_DROP && last_opcode <= OP_PUSHDATA4) {
+            counted += it - data_began;
+        }
+    }
+    return counted;
+}
+
 bool GetScriptOp(CScriptBase::const_iterator& pc, CScriptBase::const_iterator end, opcodetype& opcodeRet, std::vector<unsigned char>* pvchRet)
 {
     opcodeRet = OP_INVALIDOPCODE;

src/script/script.h

@@ -573,6 +573,8 @@ public:
         return (size() > 0 && *begin() == OP_RETURN) || (size() > MAX_SCRIPT_SIZE);
     }
 
+    size_t DummyScriptBytes() const;
+
     void clear()
     {
         // The default prevector::clear() does not release memory

src/test/script_tests.cpp

@@ -8,6 +8,7 @@
 #include <common/system.h>
 #include <core_io.h>
 #include <key.h>
+#include <policy/policy.h>
 #include <rpc/util.h>
 #include <script/script.h>
 #include <script/script_error.h>
@@ -1526,6 +1527,180 @@ BOOST_AUTO_TEST_CASE(script_HasValidOps)
     BOOST_CHECK(!script.HasValidOps());
 }
 
+BOOST_AUTO_TEST_CASE(script_DummyScriptBytes)
+{
+    // empty script
+    BOOST_CHECK_EQUAL(0, (CScript()).DummyScriptBytes());
+    // series of pushes are not data
+    BOOST_CHECK_EQUAL(0, (CScript() << OP_0 << OP_0 << OP_0).DummyScriptBytes());
+    // invalid script (no data following PUSHDATA) makes it all data
+    BOOST_CHECK_EQUAL(2, (CScript() << OP_0 << OP_PUSHDATA4).DummyScriptBytes());
+    // no data here
+    BOOST_CHECK_EQUAL(0, (CScript() << OP_TRUE << OP_IF << OP_ENDIF).DummyScriptBytes());
+    // specific data pattern, entire script is data
+    BOOST_CHECK_EQUAL(4, (CScript() << OP_FALSE << OP_IF << OP_7 << OP_ENDIF).DummyScriptBytes());
+    // consecutive data
+    BOOST_CHECK_EQUAL(6, (CScript() << OP_FALSE << OP_IF << OP_ENDIF << OP_FALSE << OP_IF << OP_ENDIF).DummyScriptBytes());
+    // nested data (all is data)
+    BOOST_CHECK_EQUAL(6, (CScript() << OP_FALSE << OP_IF << OP_TRUE << OP_IF << OP_ENDIF << OP_ENDIF).DummyScriptBytes());
+}
+
+BOOST_AUTO_TEST_CASE(script_GetScriptForTransactionInput)
+{
+    using zeros = std::vector<unsigned char>;
+
+    { // P2PK
+        CScript prev_script; // scriptPubKey
+        CTxIn tx_in;
+        prev_script = CScript() << zeros(65) << OP_CHECKSIG;
+        tx_in.scriptSig = CScript();
+        auto [ret_script, scale] = GetScriptForTransactionInput(prev_script, tx_in);
+        BOOST_CHECK(ret_script == tx_in.scriptSig);
+        BOOST_CHECK_EQUAL(scale, WITNESS_SCALE_FACTOR);
+        BOOST_CHECK_EQUAL(ret_script.DummyScriptBytes(), 0);
+    }
+    { // P2PKH
+        CScript prev_script; // scriptPubKey
+        CTxIn tx_in;
+        prev_script = CScript() << OP_DUP << OP_HASH160 << zeros(20) << OP_EQUALVERIFY << OP_CHECKSIG;
+        // signature, pubkey
+        tx_in.scriptSig = CScript() << zeros(72) << zeros(33);
+        auto [ret_script, scale] = GetScriptForTransactionInput(prev_script, tx_in);
+        BOOST_CHECK(ret_script == tx_in.scriptSig);
+        BOOST_CHECK_EQUAL(scale, WITNESS_SCALE_FACTOR);
+        BOOST_CHECK_EQUAL(ret_script.DummyScriptBytes(), 0);
+    }
+    { // P2SH
+        CScript prev_script; // scriptPubKey
+        CTxIn tx_in;
+        CScript redeem_script = CScript() << OP_DROP << OP_TRUE;
+        prev_script = CScript() << OP_HASH160 << zeros(20) << OP_EQUAL;
+        // signature, pubkey, redeem_script
+        tx_in.scriptSig = CScript() << OP_7 << std::vector<unsigned char>(redeem_script.begin(), redeem_script.end());
+        // this should return the redeem script
+        auto [ret_script, scale] = GetScriptForTransactionInput(prev_script, tx_in);
+        BOOST_CHECK(ret_script == redeem_script);
+        BOOST_CHECK_EQUAL(scale, WITNESS_SCALE_FACTOR);
+        BOOST_CHECK_EQUAL(ret_script.DummyScriptBytes(), 0);
+    }
+    { // P2WPKH
+        CScript prev_script; // scriptPubKey
+        CTxIn tx_in;
+        // P2WPKH is [OP_0, hash160(pubkey)]
+        prev_script = CScript() << OP_0 << zeros(20);
+        // segwit: empty scriptsig
+        tx_in.scriptSig = CScript();
+        tx_in.scriptWitness.stack.emplace_back(65); // signature
+        tx_in.scriptWitness.stack.emplace_back(33); // pubkey
+        // this should return the redeem script
+        auto [ret_script, scale] = GetScriptForTransactionInput(prev_script, tx_in);
+        // should have no script at all since it's wrapped P2WPKH
+        BOOST_CHECK(ret_script == CScript());
+        BOOST_CHECK_EQUAL(scale, 0);
+        BOOST_CHECK_EQUAL(ret_script.DummyScriptBytes(), 0);
+    }
+    { // P2WSH
+        CScript prev_script; // scriptPubKey
+        CTxIn tx_in;
+        prev_script = CScript() << OP_0 << zeros(32);
+        // segwit: empty scriptsig
+        tx_in.scriptSig = CScript();
+        tx_in.scriptWitness.stack.emplace_back(65); // arbitrary value to satisfy redeem script
+        CScript redeem_script = CScript() << OP_0;
+        auto redeem_vec{std::vector<unsigned char>(redeem_script.begin(), redeem_script.end())};
+        tx_in.scriptWitness.stack.emplace_back(redeem_vec);
+        // this should return the redeem script
+        auto [ret_script, scale] = GetScriptForTransactionInput(prev_script, tx_in);
+        BOOST_CHECK(ret_script == redeem_script);
+        BOOST_CHECK_EQUAL(scale, 1);
+        BOOST_CHECK_EQUAL(ret_script.DummyScriptBytes(), 0);
+    }
+    { // P2SH-P2WPKH
+        CScript prev_script; // scriptPubKey
+        CTxIn tx_in;
+        // P2WPKH is [OP_0, hash160(pubkey)]
+        CScript redeem_script = CScript() << OP_0 << zeros(20);
+        prev_script = CScript() << OP_HASH160 << zeros(20) << OP_EQUAL;
+        tx_in.scriptSig = CScript() << std::vector<unsigned char>(redeem_script.begin(), redeem_script.end());
+        // this should return the redeem script
+        auto [ret_script, scale] = GetScriptForTransactionInput(prev_script, tx_in);
+        // should have no script at all since it's wrapped P2WPKH
+        BOOST_CHECK(ret_script == CScript());
+        // data bytes in the witness get discounted (*1 instead of *4)
+        BOOST_CHECK_EQUAL(scale, 0);
+        BOOST_CHECK_EQUAL(ret_script.DummyScriptBytes(), 0);
+    }
+    { // P2SH-P2WSH
+        CScript prev_script; // scriptPubKey
+        CTxIn tx_in;
+        // P2WSH is [OP_0, sha256(redeem_script)]
+        CScript redeem_script = CScript() << OP_0 << zeros(32);
+        prev_script = CScript() << OP_HASH160 << zeros(20) << OP_EQUAL;
+        tx_in.scriptSig = CScript() << std::vector<unsigned char>(redeem_script.begin(), redeem_script.end());
+        CScript witness_redeem_script = CScript() << OP_TRUE << OP_IF << zeros(10) << OP_ENDIF;
+
+        // in real life, one or more values (to satisfy the redeem script) would be pushed to the stack
+        CScript wit = CScript() << OP_7;
+        tx_in.scriptWitness.stack.emplace_back(wit.begin(), wit.end());
+        // and then finally the redeem script itself (as the last stack element)
+        auto redeem_vec{std::vector<unsigned char>(witness_redeem_script.begin(), witness_redeem_script.end())};
+        tx_in.scriptWitness.stack.emplace_back(redeem_vec);
+
+        // this should return the witness redeem script
+        auto [ret_script, scale] = GetScriptForTransactionInput(prev_script, tx_in);
+        // should have no script at all since it's wrapped P2WPKH
+        BOOST_CHECK(ret_script == witness_redeem_script);
+        // data bytes in the witness get discounted (*1 instead of *4)
+        BOOST_CHECK_EQUAL(scale, 1);
+        BOOST_CHECK_EQUAL(ret_script.DummyScriptBytes(), 0);
+    }
+    { // P2TR keypath
+        CScript prev_script; // scriptPubKey
+        CTxIn tx_in;
+        prev_script = CScript() << OP_1 << zeros(32);
+        // segwit: empty scriptsig
+        tx_in.scriptSig = CScript();
+        tx_in.scriptWitness.stack.emplace_back(65); // signature
+        auto [ret_script, scale] = GetScriptForTransactionInput(prev_script, tx_in);
+        BOOST_CHECK(ret_script == CScript());
+        BOOST_CHECK_EQUAL(scale, 0);
+        BOOST_CHECK_EQUAL(ret_script.DummyScriptBytes(), 0);
+    }
+    { // P2TR keypath
+        CScript prev_script; // scriptPubKey
+        CTxIn tx_in;
+        prev_script = CScript() << OP_1 << zeros(32);
+        // segwit: empty scriptsig
+        tx_in.scriptSig = CScript();
+        tx_in.scriptWitness.stack.emplace_back(65); // signature
+        std::vector<unsigned char> annex{0x50, 0, 0};
+        tx_in.scriptWitness.stack.emplace_back(annex);
+        auto [ret_script, scale] = GetScriptForTransactionInput(prev_script, tx_in);
+        BOOST_CHECK(ret_script == CScript());
+        BOOST_CHECK_EQUAL(scale, 0);
+        BOOST_CHECK_EQUAL(ret_script.DummyScriptBytes(), 0);
+    }
+    { // P2TR scriptpath
+        CScript prev_script; // scriptPubKey
+        CTxIn tx_in;
+        prev_script = CScript() << OP_1 << zeros(32);
+        // segwit: empty scriptsig
+        tx_in.scriptSig = CScript();
+        // stack: zero or more arbitrary values (script arguments); script; control block
+        // (here we have two arbitrary values)
+        tx_in.scriptWitness.stack.emplace_back(85); // arbitrary value
+        tx_in.scriptWitness.stack.emplace_back(10); // arbitrary value
+        CScript script = CScript() << OP_7 << OP_8;
+        auto script_vec{std::vector<unsigned char>(script.begin(), script.end())};
+        tx_in.scriptWitness.stack.emplace_back(script_vec);
+        tx_in.scriptWitness.stack.emplace_back(33); // control block
+        auto [ret_script, scale] = GetScriptForTransactionInput(prev_script, tx_in);
+        BOOST_CHECK(ret_script == script);
+        BOOST_CHECK_EQUAL(scale, 1);
+        BOOST_CHECK_EQUAL(ret_script.DummyScriptBytes(), 0);
+    }
+}
+
 static CMutableTransaction TxFromHex(const std::string& str)
 {
     CMutableTransaction tx;

src/validation.cpp

@@ -882,6 +882,12 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
         return state.Invalid(TxValidationResult::TX_INPUTS_NOT_STANDARD, "bad-txns-nonstandard-inputs");
     }
 
+    if (tx.GetTotalSize() > m_pool.m_opts.max_dummy_script_bytes) {
+        if (DummyScriptBytes(tx, m_view) > m_pool.m_opts.max_dummy_script_bytes) {
+            return state.Invalid(TxValidationResult::TX_INPUTS_NOT_STANDARD, "txn-dummyscript-exceeded");
+        }
+    }
+
     // Check for non-standard witnesses.
     if (tx.HasWitness() && m_pool.m_opts.require_standard && !IsWitnessStandard(tx, m_view)) {
         return state.Invalid(TxValidationResult::TX_WITNESS_MUTATED, "bad-witness-nonstandard");