1 files changed, 76 insertions, 8 deletions
diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index b4c163c841..cf1953ad22 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -1,15 +1,17 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2020 The Bitcoin Core developers
+// Copyright (c) 2009-2021 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_SCRIPT_INTERPRETER_H
 #define BITCOIN_SCRIPT_INTERPRETER_H
 
+#include <hash.h>
 #include <script/script_error.h>
 #include <span.h>
 #include <primitives/transaction.h>
 
+#include <optional>
 #include <vector>
 #include <stdint.h>
 
@@ -38,8 +40,7 @@ enum
  *  All flags are intended to be soft forks: the set of acceptable scripts under
  *  flags (A | B) is a subset of the acceptable scripts under flag (A).
  */
-enum
-{
+enum : uint32_t {
     SCRIPT_VERIFY_NONE      = 0,
 
     // Evaluate P2SH subscripts (BIP16).
@@ -139,6 +140,10 @@ enum
 
     // Making unknown public key versions (in BIP 342 scripts) non-standard
     SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE = (1U << 20),
+
+    // Constants to point to the highest flag in use. Add new flags above this line.
+    //
+    SCRIPT_VERIFY_END_MARKER
 };
 
 bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror);
@@ -166,8 +171,15 @@ struct PrecomputedTransactionData
 
     PrecomputedTransactionData() = default;
 
+    /** Initialize this PrecomputedTransactionData with transaction data.
+     *
+     * @param[in]   tx             The transaction for which data is being precomputed.
+     * @param[in]   spent_outputs  The CTxOuts being spent, one for each tx.vin, in order.
+     * @param[in]   force          Whether to precompute data for all optional features,
+     *                             regardless of what is in the inputs (used at signing
+     *                             time, when the inputs aren't filled in yet). */
     template <class T>
-    void Init(const T& tx, std::vector<CTxOut>&& spent_outputs);
+    void Init(const T& tx, std::vector<CTxOut>&& spent_outputs, bool force = false);
 
     template <class T>
     explicit PrecomputedTransactionData(const T& tx);
@@ -204,6 +216,9 @@ struct ScriptExecutionData
     bool m_validation_weight_left_init = false;
     //! How much validation weight is left (decremented for every successful non-empty signature check).
     int64_t m_validation_weight_left;
+
+    //! The hash of the corresponding output
+    std::optional<uint256> m_output_hash;
 };
 
 /** Signature hash sizes */
@@ -218,6 +233,10 @@ static constexpr size_t TAPROOT_CONTROL_NODE_SIZE = 32;
 static constexpr size_t TAPROOT_CONTROL_MAX_NODE_COUNT = 128;
 static constexpr size_t TAPROOT_CONTROL_MAX_SIZE = TAPROOT_CONTROL_BASE_SIZE + TAPROOT_CONTROL_NODE_SIZE * TAPROOT_CONTROL_MAX_NODE_COUNT;
 
+extern const CHashWriter HASHER_TAPSIGHASH; //!< Hasher with tag "TapSighash" pre-fed to it.
+extern const CHashWriter HASHER_TAPLEAF;    //!< Hasher with tag "TapLeaf" pre-fed to it.
+extern const CHashWriter HASHER_TAPBRANCH;  //!< Hasher with tag "TapBranch" pre-fed to it.
+
 template <class T>
 uint256 SignatureHash(const CScript& scriptCode, const T& txTo, unsigned int nIn, int nHashType, const CAmount& amount, SigVersion sigversion, const PrecomputedTransactionData* cache = nullptr);
 
@@ -229,7 +248,7 @@ public:
         return false;
     }
 
-    virtual bool CheckSchnorrSignature(Span<const unsigned char> sig, Span<const unsigned char> pubkey, SigVersion sigversion, const ScriptExecutionData& execdata, ScriptError* serror = nullptr) const
+    virtual bool CheckSchnorrSignature(Span<const unsigned char> sig, Span<const unsigned char> pubkey, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* serror = nullptr) const
     {
         return false;
     }
@@ -247,11 +266,24 @@ public:
     virtual ~BaseSignatureChecker() {}
 };
 
+/** Enum to specify what *TransactionSignatureChecker's behavior should be
+ *  when dealing with missing transaction data.
+ */
+enum class MissingDataBehavior
+{
+    ASSERT_FAIL,  //!< Abort execution through assertion failure (for consensus code)
+    FAIL,         //!< Just act as if the signature was invalid
+};
+
+template<typename T>
+bool SignatureHashSchnorr(uint256& hash_out, ScriptExecutionData& execdata, const T& tx_to, uint32_t in_pos, uint8_t hash_type, SigVersion sigversion, const PrecomputedTransactionData& cache, MissingDataBehavior mdb);
+
 template <class T>
 class GenericTransactionSignatureChecker : public BaseSignatureChecker
 {
 private:
     const T* txTo;
+    const MissingDataBehavior m_mdb;
     unsigned int nIn;
     const CAmount amount;
     const PrecomputedTransactionData* txdata;
@@ -261,10 +293,10 @@ protected:
     virtual bool VerifySchnorrSignature(Span<const unsigned char> sig, const XOnlyPubKey& pubkey, const uint256& sighash) const;
 
 public:
-    GenericTransactionSignatureChecker(const T* txToIn, unsigned int nInIn, const CAmount& amountIn) : txTo(txToIn), nIn(nInIn), amount(amountIn), txdata(nullptr) {}
-    GenericTransactionSignatureChecker(const T* txToIn, unsigned int nInIn, const CAmount& amountIn, const PrecomputedTransactionData& txdataIn) : txTo(txToIn), nIn(nInIn), amount(amountIn), txdata(&txdataIn) {}
+    GenericTransactionSignatureChecker(const T* txToIn, unsigned int nInIn, const CAmount& amountIn, MissingDataBehavior mdb) : txTo(txToIn), m_mdb(mdb), nIn(nInIn), amount(amountIn), txdata(nullptr) {}
+    GenericTransactionSignatureChecker(const T* txToIn, unsigned int nInIn, const CAmount& amountIn, const PrecomputedTransactionData& txdataIn, MissingDataBehavior mdb) : txTo(txToIn), m_mdb(mdb), nIn(nInIn), amount(amountIn), txdata(&txdataIn) {}
     bool CheckECDSASignature(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const override;
-    bool CheckSchnorrSignature(Span<const unsigned char> sig, Span<const unsigned char> pubkey, SigVersion sigversion, const ScriptExecutionData& execdata, ScriptError* serror = nullptr) const override;
+    bool CheckSchnorrSignature(Span<const unsigned char> sig, Span<const unsigned char> pubkey, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* serror = nullptr) const override;
     bool CheckLockTime(const CScriptNum& nLockTime) const override;
     bool CheckSequence(const CScriptNum& nSequence) const override;
 };
@@ -272,12 +304,48 @@ public:
 using TransactionSignatureChecker = GenericTransactionSignatureChecker<CTransaction>;
 using MutableTransactionSignatureChecker = GenericTransactionSignatureChecker<CMutableTransaction>;
 
+class DeferringSignatureChecker : public BaseSignatureChecker
+{
+protected:
+    BaseSignatureChecker& m_checker;
+
+public:
+    DeferringSignatureChecker(BaseSignatureChecker& checker) : m_checker(checker) {}
+
+    bool CheckECDSASignature(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const override
+    {
+        return m_checker.CheckECDSASignature(scriptSig, vchPubKey, scriptCode, sigversion);
+    }
+
+    bool CheckSchnorrSignature(Span<const unsigned char> sig, Span<const unsigned char> pubkey, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* serror = nullptr) const override
+    {
+        return m_checker.CheckSchnorrSignature(sig, pubkey, sigversion, execdata, serror);
+    }
+
+    bool CheckLockTime(const CScriptNum& nLockTime) const override
+    {
+        return m_checker.CheckLockTime(nLockTime);
+    }
+    bool CheckSequence(const CScriptNum& nSequence) const override
+    {
+        return m_checker.CheckSequence(nSequence);
+    }
+};
+
+/** Compute the BIP341 tapleaf hash from leaf version & script. */
+uint256 ComputeTapleafHash(uint8_t leaf_version, const CScript& script);
+/** Compute the BIP341 taproot script tree Merkle root from control block and leaf hash.
+ *  Requires control block to have valid length (33 + k*32, with k in {0,1,..,128}). */
+uint256 ComputeTaprootMerkleRoot(Span<const unsigned char> control, const uint256& tapleaf_hash);
+
 bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* error = nullptr);
 bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* error = nullptr);
 bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror = nullptr);
 
 size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags);
 
+bool CheckMinimalPush(const std::vector<unsigned char>& data, opcodetype opcode);
+
 int FindAndDelete(CScript& script, const CScript& b);
 
 #endif // BITCOIN_SCRIPT_INTERPRETER_H