Treat amount<0 also as missing data for P2WPKH/P2WSH

Historically lack of amount data has been treated as amount==-1. Change
this and treat it as missing data, as introduced in the previous commits.

To be minimally invasive, do this at SignatureHash() call sites rather
than inside SignatureHash() (which currently has no means or returning
a failure code).

2 files changed, 6 insertions, 0 deletions

diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 2b10f5b0df..abc0625bb1 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -1681,6 +1681,9 @@ bool GenericTransactionSignatureChecker<T>::CheckECDSASignature(const std::vecto
     int nHashType = vchSig.back();
     vchSig.pop_back();
 
+    // Witness sighashes need the amount.
+    if (sigversion == SigVersion::WITNESS_V0 && amount < 0) return HandleMissingData(m_mdb);
+
     uint256 sighash = SignatureHash(scriptCode, *txTo, nIn, nHashType, amount, sigversion, this->txdata);
 
     if (!VerifyECDSASignature(vchSig, pubkey, sighash))
diff --git a/src/script/sign.cpp b/src/script/sign.cpp
index fb3466f320..6426c8de59 100644
--- a/src/script/sign.cpp
+++ b/src/script/sign.cpp
@@ -26,6 +26,9 @@ bool MutableTransactionSignatureCreator::CreateSig(const SigningProvider& provid
     if (sigversion == SigVersion::WITNESS_V0 && !key.IsCompressed())
         return false;
 
+    // Signing for witness scripts needs the amount.
+    if (sigversion == SigVersion::WITNESS_V0 && amount < 0) return false;
+
     uint256 hash = SignatureHash(scriptCode, *txTo, nIn, nHashType, amount, sigversion);
     if (!key.Sign(hash, vchSig))
         return false;