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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Diff rows 401–550 of 550. Line numbers refer to the original before/after files.

+ Added− RemovedUnmarked lines are context.

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src/policy/policy.cpp CHANGED Viewed

@@ -277,9 +477,15 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) (continued)
                 return false;
             prevScript = CScript(stack.back().begin(), stack.back().end());
             p2sh = true;
         }
@@ -289,18 +495,25 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
         // 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() == WITNESS_V0_SCRIPTHASH_SIZE) {
             if (tx.vin[i].scriptWitness.stack.back().size() > MAX_STANDARD_P2WSH_SCRIPT_SIZE)
-                return false;
             size_t sizeWitnessStack = tx.vin[i].scriptWitness.stack.size() - 1;
             if (sizeWitnessStack > MAX_STANDARD_P2WSH_STACK_ITEMS)
-                return false;
             for (unsigned int j = 0; j < sizeWitnessStack; j++) {
                 if (tx.vin[i].scriptWitness.stack[j].size() > MAX_STANDARD_P2WSH_STACK_ITEM_SIZE)
-                    return false;
             }
         }
@@ -312,17 +525,28 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
             std::span stack{tx.vin[i].scriptWitness.stack};
             if (stack.size() >= 2 && !stack.back().empty() && stack.back()[0] == ANNEX_TAG) {
                 // Annexes are nonstandard as long as no semantics are defined for them.
-                return false;
             }
             if (stack.size() >= 2) {
                 // Script path spend (2 or more stack elements after removing optional annex)
                 const auto& control_block = SpanPopBack(stack);
                 SpanPopBack(stack); // Ignore script
-                if (control_block.empty()) return false; // Empty control block is invalid
                 if ((control_block[0] & TAPROOT_LEAF_MASK) == TAPROOT_LEAF_TAPSCRIPT) {
                     // Leaf version 0xc0 (aka Tapscript, see BIP 342)
                     for (const auto& item : stack) {
-                        if (item.size() > MAX_STANDARD_TAPSCRIPT_STACK_ITEM_SIZE) return false;
                     }
                 }
             } else if (stack.size() == 1) {
@@ -330,6 +554,7 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs)
                 // (no policy rules apply)
             } else {
                 // 0 stack elements; this is already invalid by consensus rules
                 return false;
             }
         }
@@ -392,3 +617,78 @@ int64_t GetVirtualTransactionInputSize(const CTxIn& txin, int64_t nSigOpCost, un
 {
     return GetVirtualTransactionSize(GetTransactionInputWeight(txin), nSigOpCost, bytes_per_sigop);
 }

+                out_reason = reason_prefix + "scriptcheck-missing";
                 return false;
+            }
             prevScript = CScript(stack.back().begin(), stack.back().end());
             p2sh = true;
         }
         // Non-witness program must not be associated with any witness
         if (!prevScript.IsWitnessProgram(witnessversion, witnessprogram))
+        {
+            out_reason = reason_prefix + "nonwitness-input";
             return false;
+        }
+        if (GetSerializeSize(tx.vin[i].scriptWitness.stack) > g_script_size_policy_limit) {
+            MaybeReject("witness-size");
+        }
         // Check P2WSH standard limits
         if (witnessversion == 0 && witnessprogram.size() == WITNESS_V0_SCRIPTHASH_SIZE) {
             if (tx.vin[i].scriptWitness.stack.back().size() > MAX_STANDARD_P2WSH_SCRIPT_SIZE)
+                MaybeReject("script-size");
             size_t sizeWitnessStack = tx.vin[i].scriptWitness.stack.size() - 1;
             if (sizeWitnessStack > MAX_STANDARD_P2WSH_STACK_ITEMS)
+                MaybeReject("stackitem-count");
             for (unsigned int j = 0; j < sizeWitnessStack; j++) {
                 if (tx.vin[i].scriptWitness.stack[j].size() > MAX_STANDARD_P2WSH_STACK_ITEM_SIZE)
+                    MaybeReject("stackitem-size");
             }
         }
             std::span stack{tx.vin[i].scriptWitness.stack};
             if (stack.size() >= 2 && !stack.back().empty() && stack.back()[0] == ANNEX_TAG) {
                 // Annexes are nonstandard as long as no semantics are defined for them.
+                MaybeReject("taproot-annex");
+                // If reject reason is ignored, continue as if the annex wasn't there.
+                SpanPopBack(stack);
             }
             if (stack.size() >= 2) {
                 // Script path spend (2 or more stack elements after removing optional annex)
                 const auto& control_block = SpanPopBack(stack);
                 SpanPopBack(stack); // Ignore script
+                if (control_block.empty()) {
+                    // Empty control block is invalid
+                    out_reason = reason_prefix + "taproot-control-missing";
+                    return false;
+                }
                 if ((control_block[0] & TAPROOT_LEAF_MASK) == TAPROOT_LEAF_TAPSCRIPT) {
                     // Leaf version 0xc0 (aka Tapscript, see BIP 342)
+                    if (!ignore_rejects.count(reason_prefix + "taproot-stackitem-size")) {
                     for (const auto& item : stack) {
+                            if (item.size() > MAX_STANDARD_TAPSCRIPT_STACK_ITEM_SIZE) {
+                                out_reason = reason_prefix + "taproot-stackitem-size";
+                                return false;
+                            }
+                        }
                     }
                 }
             } else if (stack.size() == 1) {
                 // (no policy rules apply)
             } else {
                 // 0 stack elements; this is already invalid by consensus rules
+                out_reason = reason_prefix + "taproot-witness-missing";
                 return false;
             }
         }
 {
     return GetVirtualTransactionSize(GetTransactionInputWeight(txin), nSigOpCost, bytes_per_sigop);
 }
+std::pair<CScript, unsigned int> GetScriptForTransactionInput(CScript prevScript, const CTxIn& txin)
+{
+    bool p2sh = false;
+    if (prevScript.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);
+        }
+        prevScript = CScript(stack.back().begin(), stack.back().end());
+        p2sh = true;
+    }
+    int witnessversion = 0;
+    std::vector<unsigned char> witnessprogram;
+    if (!prevScript.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 ? prevScript : txin.scriptSig, WITNESS_SCALE_FACTOR);
+    }
+    std::span stack{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();
+        prevScript = CScript(script_data.begin(), script_data.end());
+        return std::make_pair(prevScript, 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
+            prevScript = CScript(stack.back().begin(), stack.back().end());
+            return std::make_pair(prevScript, 1);
+        }
+    }
+    return std::make_pair(CScript(), 0);
+}
+std::pair<size_t, size_t> DatacarrierBytes(const CTransaction& tx, const CCoinsViewCache& view)
+{
+    std::pair<size_t, size_t> ret{0, 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);
+        const auto dcb = ScriptDatacarrierBytes(script, 0, &txin.scriptWitness);
+        ret.first += dcb.first;
+        ret.second += dcb.second;
+    }
+    for (size_t i{tx.vout.size()}; i; ) {
+        const CTxOut& txout = tx.vout[--i];
+        const auto dcb = ScriptDatacarrierBytes(txout.scriptPubKey, tx.vout.size() - i);
+        ret.first += dcb.first;
+        ret.second += dcb.second;
+    }
+    return ret;
+}
+bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& inputs)
+{
+    std::string reason;
+    return IsWitnessStandard(tx, inputs, "", reason);
+}