diff options
Diffstat (limited to 'src/policy/policy.cpp')
| -rw-r--r-- | src/policy/policy.cpp | 56 |
1 files changed, 46 insertions, 10 deletions
diff --git a/src/policy/policy.cpp b/src/policy/policy.cpp index 0e9820da1e..4e33fd6cb5 100644 --- a/src/policy/policy.cpp +++ b/src/policy/policy.cpp @@ -9,7 +9,7 @@ #include <consensus/validation.h> #include <coins.h> - +#include <span.h> CAmount GetDustThreshold(const CTxOut& txout, const CFeeRate& dustRelayFeeIn) { @@ -92,14 +92,15 @@ bool IsStandardTx(const CTransaction& tx, bool permit_bare_multisig, const CFeeR for (const CTxIn& txin : tx.vin) { - // Biggest 'standard' txin is a 15-of-15 P2SH multisig with compressed - // keys (remember the 520 byte limit on redeemScript size). That works - // out to a (15*(33+1))+3=513 byte redeemScript, 513+1+15*(73+1)+3=1627 - // bytes of scriptSig, which we round off to 1650 bytes for 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() > 1650) { + // Biggest 'standard' txin involving only keys is a 15-of-15 P2SH + // multisig with compressed keys (remember the 520 byte limit on + // redeemScript size). That works out to a (15*(33+1))+3=513 byte + // redeemScript, 513+1+15*(73+1)+3=1627 bytes of scriptSig, which + // we round off to 1650(MAX_STANDARD_SCRIPTSIG_SIZE) bytes for + // 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; } @@ -155,7 +156,7 @@ bool IsStandardTx(const CTransaction& tx, bool permit_bare_multisig, const CFeeR * * Note that only the non-witness portion of the transaction is checked here. */ -bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) +bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs, bool taproot_active) { if (tx.IsCoinBase()) return true; // Coinbases don't use vin normally @@ -183,6 +184,9 @@ bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) if (subscript.GetSigOpCount(true) > MAX_P2SH_SIGOPS) { return false; } + } else if (whichType == TxoutType::WITNESS_V1_TAPROOT) { + // Don't allow Taproot spends unless Taproot is active. + if (!taproot_active) return false; } } @@ -206,6 +210,7 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) // get the scriptPubKey corresponding to this input: CScript prevScript = prev.scriptPubKey; + bool p2sh = false; 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 @@ -216,6 +221,7 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) if (stack.empty()) return false; prevScript = CScript(stack.back().begin(), stack.back().end()); + p2sh = true; } int witnessversion = 0; @@ -237,6 +243,36 @@ bool IsWitnessStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs) return false; } } + + // Check policy limits for Taproot spends: + // - MAX_STANDARD_TAPSCRIPT_STACK_ITEM_SIZE limit for stack item size + // - No annexes + if (witnessversion == 1 && witnessprogram.size() == WITNESS_V1_TAPROOT_SIZE && !p2sh) { + // Taproot spend (non-P2SH-wrapped, version 1, witness program size 32; see BIP 341) + auto stack = MakeSpan(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) { + // Key path spend (1 stack element after removing optional annex) + // (no policy rules apply) + } else { + // 0 stack elements; this is already invalid by consensus rules + return false; + } + } } return true; } |