v31.1-roots.1 · Commit 2: [PATCH 02/17] feat(policy): preserve Roots parsing and local transaction checks

src/policy/policy.cpp

Before: src/policy/policy.cpp · After: src/policy/policy.cpp

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index 46ec238c3b18fd1c0a5ce35f25d1b619317dafda..d0455dd98cedea3adbc884b10ed5a1e58c570eb1 100644

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src/policy/policy.cpp CHANGED Viewed

@@ -12,6 +12,7 @@
 #include <consensus/consensus.h>
 #include <consensus/validation.h>
 #include <policy/feerate.h>
+#include <policy/settings.h>
 #include <primitives/transaction.h>
 #include <script/interpreter.h>
 #include <script/script.h>
@@ -21,6 +22,8 @@
 #include <algorithm>
 #include <cstddef>
+#include <limits>
+#include <utility>
 #include <vector>
 CAmount GetDustThreshold(const CTxOut& txout, const CFeeRate& dustRelayFeeIn)
@@ -42,7 +45,7 @@ CAmount GetDustThreshold(const CTxOut& txout, const CFeeRate& dustRelayFeeIn)
     if (txout.scriptPubKey.IsUnspendable())
         return 0;
-    uint64_t nSize{GetSerializeSize(txout)};
+    size_t nSize = GetSerializeSize(txout);
     int witnessversion = 0;
     std::vector<unsigned char> witnessprogram;
@@ -76,6 +79,10 @@ std::vector<uint32_t> GetDust(const CTransaction& tx, CFeeRate dust_relay_rate)
     return dust_outputs;
 }
+/**
+ * Note this must assign whichType even if returning false, in case
+ * IsStandardTx ignores the "scriptpubkey" rejection.
+ */
 bool IsStandard(const CScript& scriptPubKey, TxoutType& whichType)
 {
     std::vector<std::vector<unsigned char> > vSolutions;
@@ -96,11 +103,111 @@ bool IsStandard(const CScript& scriptPubKey, TxoutType& whichType)
     return true;
 }
-bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_datacarrier_bytes, bool permit_bare_multisig, const CFeeRate& dust_relay_fee, std::string& reason)
+static inline bool MaybeReject_(std::string& out_reason, const std::string& reason, const std::string& reason_prefix, const ignore_rejects_type& ignore_rejects) {
+    if (ignore_rejects.count(reason_prefix + reason)) {
+        return false;
+    }
+    out_reason = reason_prefix + reason;
+    return true;
+}
+#define MaybeReject(reason)  do {  \
+    if (MaybeReject_(out_reason, reason, reason_prefix, ignore_rejects)) {  \
+        return false;  \
+    }  \
+} while(0)
+namespace {
+size_t OlgaBytes(const CScript& script, size_t remaining_outputs)
+{
+    if (!script.IsPayToWitnessScriptHash()) return 0;
+    const size_t payload_size{(size_t{script[2]} << 8) | script[3]};
+    const size_t outputs{(payload_size + 1) / WITNESS_V0_SCRIPTHASH_SIZE + 1};
+    if (remaining_outputs < outputs) return 0;
+    if ((script[4] | 0x20) != 's' || (script[5] | 0x20) != 't' ||
+        (script[6] | 0x20) != 'a' || (script[7] | 0x20) != 'm' ||
+        (script[8] | 0x20) != 'p' || script[9] != ':') {
+        return 0;
+    }
+    return outputs * (WITNESS_V0_SCRIPTHASH_SIZE + 1 + 8);
+}
+size_t OpNetWitnessBytes(const CScriptWitness& witness)
+{
+    const auto& stack{witness.stack};
+    if (stack.size() != 5 || stack[4].size() != 65) return 0;
+    const CScript tapscript{stack[3].begin(), stack[3].end()};
+    bool found_opnet{false};
+    size_t deduct{0};
+    CScript::const_iterator pc{tapscript.begin()};
+    opcodetype opcode{OP_INVALIDOPCODE};
+    opcodetype last_opcode{OP_INVALIDOPCODE};
+    std::vector<unsigned char> data;
+    while (pc < tapscript.end()) {
+        last_opcode = opcode;
+        if (!tapscript.GetOp(pc, opcode, data)) break;
+        if (data.size() == 2 && data[0] == 0x6f && data[1] == 0x70) found_opnet = true;
+        if (opcode == OP_CHECKSIGVERIFY && last_opcode == 0x20) deduct += 34;
+    }
+    return found_opnet ? stack[0].size() + stack[3].size() - deduct : 0;
+}
+std::pair<size_t, size_t> ScriptDatacarrierBytes(const CScript& script, size_t remaining_outputs, const CScriptWitness* witness = nullptr)
 {
+    if (const size_t olga_bytes{OlgaBytes(script, remaining_outputs)}; olga_bytes) return {0, olga_bytes};
+    if (witness) {
+        if (const size_t opnet_bytes{OpNetWitnessBytes(*witness)}; opnet_bytes) return {0, opnet_bytes};
+    }
+    size_t counted{0};
+    opcodetype opcode{OP_INVALIDOPCODE};
+    opcodetype last_opcode{OP_INVALIDOPCODE};
+    std::vector<unsigned char> push_data;
+    unsigned int inside_noop{0};
+    unsigned int inside_conditional{0};
+    CScript::const_iterator opcode_it{script.begin()};
+    CScript::const_iterator data_began{script.begin()};
+    for (CScript::const_iterator it{script.begin()}; it < script.end(); last_opcode = opcode) {
+        opcode_it = it;
+        if (!script.GetOp(it, opcode, push_data)) return {0, script.size()};
+        if (opcode == OP_IF || opcode == OP_NOTIF) {
+            ++inside_conditional;
+        } else if (opcode == OP_ENDIF) {
+            if (!inside_conditional) return {0, script.size()};
+            --inside_conditional;
+        } else if (opcode == OP_RETURN && !inside_conditional) {
+            return {script.size(), 0};
+        }
+        if (inside_noop) {
+            if (opcode == OP_IF || opcode == OP_NOTIF) {
+                ++inside_noop;
+            } else if (opcode == OP_ENDIF && --inside_noop == 0) {
+                counted += it - data_began + 1;
+            }
+        } else if (opcode == OP_IF && last_opcode == OP_FALSE) {
+            inside_noop = 1;
+            data_began = opcode_it;
+        } else if (opcode <= OP_PUSHDATA4) {
+            data_began = opcode_it;
+        } else if (opcode == OP_DROP && last_opcode <= OP_PUSHDATA4) {
+            counted += it - data_began;
+        }
+    }
+    return {0, counted};
+}
+} // namespace
+bool IsStandardTx(const CTransaction& tx, const StandardnessOptions& opts, std::string& out_reason, const ignore_rejects_type& ignore_rejects)
+{
+    const std::string reason_prefix;
     if (tx.version > TX_MAX_STANDARD_VERSION || tx.version < TX_MIN_STANDARD_VERSION) {
-        reason = "version";
-        return false;
+        MaybeReject("version");
     }
     // Extremely large transactions with lots of inputs can cost the network
@@ -109,8 +216,11 @@ bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_dat
     // to MAX_STANDARD_TX_WEIGHT mitigates CPU exhaustion attacks.
     unsigned int sz = GetTransactionWeight(tx);
     if (sz > MAX_STANDARD_TX_WEIGHT) {
-        reason = "tx-size";
-        return false;
+        MaybeReject("tx-size");
+    }
+    if (tx.nLockTime == PARASITE_CAT21_LOCKTIME && opts.reject_parasites) {
+        MaybeReject("parasite-cat21");
     }
     for (const CTxIn& txin : tx.vin)
@@ -123,50 +233,110 @@ bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_dat
         // 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() > MAX_STANDARD_SCRIPTSIG_SIZE) {
-            reason = "scriptsig-size";
-            return false;
+        if (txin.scriptSig.size() > std::min(MAX_STANDARD_SCRIPTSIG_SIZE, g_script_size_policy_limit)) {
+            MaybeReject("scriptsig-size");
         }
         if (!txin.scriptSig.IsPushOnly()) {
-            reason = "scriptsig-not-pushonly";
-            return false;
+            MaybeReject("scriptsig-not-pushonly");
         }
     }
-    unsigned int datacarrier_bytes_left = max_datacarrier_bytes.value_or(0);
+    unsigned int datacarrier_bytes_left = opts.max_datacarrier_bytes.value_or(0);
+    unsigned int nDataOut = 0;
+    unsigned int n_dust{0};
+    unsigned int n_monetary{0};
     TxoutType whichType;
-    for (const CTxOut& txout : tx.vout) {
+    for (size_t i{tx.vout.size()}; i; ) {
+        const CTxOut& txout = tx.vout[--i];
+        if (txout.scriptPubKey.size() > g_script_size_policy_limit) {
+            MaybeReject("scriptpubkey-size");
+        }
         if (!::IsStandard(txout.scriptPubKey, whichType)) {
-            reason = "scriptpubkey";
-            return false;
+            MaybeReject("scriptpubkey");
+        }
+        if (whichType == TxoutType::WITNESS_UNKNOWN && !opts.acceptunknownwitness) {
+            MaybeReject("scriptpubkey-unknown-witnessversion");
+        }
+        if (whichType == TxoutType::ANCHOR && !opts.permitephemeral_anchor) {
+            MaybeReject("anchor");
+        }
+        if (IsDust(txout, opts.dust_relay_feerate)) {
+            if (whichType != TxoutType::ANCHOR && !opts.permitephemeral_send) {
+                MaybeReject("dust-nonanchor");
+            }
+            if (txout.nValue && !opts.permitephemeral_dust) {
+                MaybeReject("dust-nonzero");
+            }
+            ++n_dust;
+        } else if (whichType != TxoutType::NULL_DATA) {
+            ++n_monetary;
         }
         if (whichType == TxoutType::NULL_DATA) {
-            unsigned int size = txout.scriptPubKey.size();
+            const auto size = txout.scriptPubKey.size();
             if (size > datacarrier_bytes_left) {
-                reason = "datacarrier";
-                return false;
+                MaybeReject("datacarrier");
+                datacarrier_bytes_left = 0;
+            } else {
+                datacarrier_bytes_left -= size;
             }
-            datacarrier_bytes_left -= size;
-        } else if ((whichType == TxoutType::MULTISIG) && (!permit_bare_multisig)) {
-            reason = "bare-multisig";
-            return false;
+            if (txout.scriptPubKey.size() > 2 && txout.scriptPubKey[1] == OP_13 && opts.reject_tokens) {
+                MaybeReject("tokens-runes");
+            }
+            nDataOut++;
+            continue;
+        }
+        else if ((whichType == TxoutType::PUBKEY) && (!opts.permit_bare_pubkey)) {
+            MaybeReject("bare-pubkey");
+        }
+        else if ((whichType == TxoutType::MULTISIG) && (!opts.permit_bare_multisig)) {
+            MaybeReject("bare-multisig");
+        }
+        else if (whichType == TxoutType::WITNESS_V0_SCRIPTHASH && opts.reject_tokens && OlgaBytes(txout.scriptPubKey, tx.vout.size() - i))  {
+            MaybeReject("tokens-olga");
         }
     }
     // Only MAX_DUST_OUTPUTS_PER_TX dust is permitted(on otherwise valid ephemeral dust)
-    if (GetDust(tx, dust_relay_fee).size() > MAX_DUST_OUTPUTS_PER_TX) {
-        reason = "dust";
-        return false;
+    if (n_dust > MAX_DUST_OUTPUTS_PER_TX) {
+        MaybeReject("dust");
+    }
+    // only one OP_RETURN txout is permitted
+    if (nDataOut > 1) {
+        MaybeReject("multi-op-return");
+    }
+    if (!n_monetary) {
+        if (nDataOut && !opts.permitbaredatacarrier) {
+            MaybeReject("bare-datacarrier");
+        }
+        if ((!nDataOut) && !opts.permitbareanchor) {
+            MaybeReject("bare-anchor");
+        }
     }
     return true;
 }
+bool IsStandardTx(const CTransaction& tx, const std::optional<unsigned>& max_datacarrier_bytes, bool permit_bare_multisig, const CFeeRate& dust_relay_feerate, std::string& out_reason)
+{
+    StandardnessOptions opts;
+    opts.max_datacarrier_bytes = max_datacarrier_bytes;
+    opts.permit_bare_multisig = permit_bare_multisig;
+    opts.dust_relay_feerate = dust_relay_feerate;
+    return IsStandardTx(tx, opts, out_reason);
+}
 /**
- * Check the total number of non-witness sigops across the whole transaction, as per BIP54.
+ * Check the local transaction limit for potentially executed legacy sigops.
  */
-static bool CheckSigopsBIP54(const CTransaction& tx, const CCoinsViewCache& inputs)
+static bool CheckLegacyPolicySigops(const CTransaction& tx, const CCoinsViewCache& inputs, const StandardnessOptions& opts)
 {
     Assert(!tx.IsCoinBase());
@@ -184,7 +354,7 @@ static bool CheckSigopsBIP54(const CTransaction& tx, const CCoinsViewCache& inpu
         sigops += txin.scriptSig.GetSigOpCount(/*fAccurate=*/true);
         sigops += prev_txo.scriptPubKey.GetSigOpCount(txin.scriptSig);
-        if (sigops > MAX_TX_LEGACY_SIGOPS) {
+        if (sigops > opts.maxtxlegacysigops) {
             return false;
         }
     }
@@ -208,39 +378,62 @@ static bool CheckSigopsBIP54(const CTransaction& tx, const CCoinsViewCache& inpu
  *
  * Note that only the non-witness portion of the transaction is checked here.
  *
- * We also check the total number of non-witness sigops across the whole transaction, as per BIP54.
+ * We also check the local transaction limit for potentially executed legacy sigops.
  */
-bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
+bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs, const StandardnessOptions& opts, const std::string& reason_prefix, std::string& out_reason, const ignore_rejects_type& ignore_rejects)
 {
     if (tx.IsCoinBase()) {
         return true; // Coinbases don't use vin normally
     }
-    if (!CheckSigopsBIP54(tx, mapInputs)) {
-        return false;
+    if (!CheckLegacyPolicySigops(tx, mapInputs, opts)) {
+        MaybeReject("sigops-toomany-overall");
     }
     for (unsigned int i = 0; i < tx.vin.size(); i++) {
         const CTxOut& prev = mapInputs.AccessCoin(tx.vin[i].prevout).out;
+        if (prev.scriptPubKey.size() > g_script_size_policy_limit) {
+            MaybeReject("script-size");
+        }
         std::vector<std::vector<unsigned char> > vSolutions;
         TxoutType whichType = Solver(prev.scriptPubKey, vSolutions);
-        if (whichType == TxoutType::NONSTANDARD || whichType == TxoutType::WITNESS_UNKNOWN) {
+        if (whichType == TxoutType::NONSTANDARD) {
+            MaybeReject("script-unknown");
+        } else if (whichType == TxoutType::WITNESS_UNKNOWN) {
             // WITNESS_UNKNOWN failures are typically also caught with a policy
             // flag in the script interpreter, but it can be helpful to catch
             // this type of NONSTANDARD transaction earlier in transaction
             // validation.
-            return false;
+            MaybeReject("witness-unknown");
         } else if (whichType == TxoutType::SCRIPTHASH) {
+            if (!tx.vin[i].scriptSig.IsPushOnly()) {
+                // The only way we got this far, is if the user ignored scriptsig-not-pushonly.
+                // However, this case is invalid, and will be caught later on.
+                // But for now, we don't want to run the [possibly expensive] script here.
+                continue;
+            }
             std::vector<std::vector<unsigned char> > stack;
             // convert the scriptSig into a stack, so we can inspect the redeemScript
             if (!EvalScript(stack, tx.vin[i].scriptSig, SCRIPT_VERIFY_NONE, BaseSignatureChecker(), SigVersion::BASE))
+            {
+                // This case is also invalid or a bug
+                out_reason = reason_prefix + "scriptsig-failure";
                 return false;
+            }
             if (stack.empty())
+            {
+                // Also invalid
+                out_reason = reason_prefix + "scriptcheck-missing";
                 return false;
+            }
             CScript subscript(stack.back().begin(), stack.back().end());
+            if (subscript.size() > g_script_size_policy_limit) {
+                MaybeReject("scriptcheck-size");
+            }
             if (subscript.GetSigOpCount(true) > MAX_P2SH_SIGOPS) {
-                return false;
+                MaybeReject("scriptcheck-sigops");
             }
         }
     }
@@ -248,7 +441,14 @@ bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
     return true;
 }
-bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
+bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& map_inputs)
+{
+    StandardnessOptions opts;
+    std::string reason;
+    return AreInputsStandard(tx, map_inputs, opts, "", reason);
+}
+bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs, const std::string& reason_prefix, std::string& out_reason, const ignore_rejects_type& ignore_rejects)
 {
     if (tx.IsCoinBase())
         return true; // Coinbases are skipped
@@ -267,7 +467,7 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
         // witness stuffing detected
         if (prevScript.IsPayToAnchor()) {
-            return false;
+            MaybeReject("anchor-not-empty");
         }
         bool p2sh = false;
@@ -277,9 +477,15 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
             // 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))
+            {
+                out_reason = reason_prefix + "scriptsig-failure";
                 return false;
+            }
             if (stack.empty())
+            {