From b77b0cc507bdc716e5236b1d9880e648147e0af9 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter@wuille.net>
Date: Mon, 1 Mar 2021 16:49:59 -0800
Subject: Add MissingDataBehavior and make TransactionSignatureChecker handle
 it

This allows specifying how *TransactionSignatureChecker will behave when
presented with missing transaction data such as amounts spent, BIP341 data,
or spent outputs.

As all call sites still (implicitly) use MissingDataBehavior::ASSERT_FAIL,
this commit introduces no change in behavior.
---
 src/script/interpreter.h | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

(limited to 'src/script/interpreter.h')

diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index b4c163c841..490b337108 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -247,11 +247,21 @@ 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 <class T>
 class GenericTransactionSignatureChecker : public BaseSignatureChecker
 {
 private:
     const T* txTo;
+    const MissingDataBehavior m_mdb;
     unsigned int nIn;
     const CAmount amount;
     const PrecomputedTransactionData* txdata;
@@ -261,8 +271,8 @@ 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 = MissingDataBehavior::ASSERT_FAIL) : 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 = MissingDataBehavior::ASSERT_FAIL) : 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 CheckLockTime(const CScriptNum& nLockTime) const override;
-- 
cgit v1.2.3


From 3820090bd619ac85ab35eff376c03136fe4a9f04 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter@wuille.net>
Date: Mon, 1 Mar 2021 18:07:14 -0800
Subject: Make all SignatureChecker explicit about missing data

Remove the implicit MissingDataBehavior::ASSERT_FAIL in the
*TransationSignatureChecker constructors, and instead specify
it explicit in all call sites:
* Test code uses ASSERT_FAIL
* Validation uses ASSERT_FAIL (through CachingTransactionSignatureChecker)
  (including signet)
* libconsensus uses FAIL, matching the existing behavior of the
  non-amount API (and the extended required data for taproot validation
  is not available yet)
* Signing code uses FAIL
---
 src/script/interpreter.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'src/script/interpreter.h')

diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index 490b337108..970543ce38 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -271,8 +271,8 @@ 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, MissingDataBehavior mdb = MissingDataBehavior::ASSERT_FAIL) : 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 = MissingDataBehavior::ASSERT_FAIL) : txTo(txToIn), m_mdb(mdb), 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 CheckLockTime(const CScriptNum& nLockTime) const override;
-- 
cgit v1.2.3