lbrycrd/src/psbt.cpp
Glenn Willen 102faad81e Factor out combine / finalize / extract PSBT helpers
Refactor the new CombinePSBT, FinalizePSBT, and FinalizeAndExtractPSBT
general-purpose functions out of the combinepsbt and finalizepsbt RPCs,
for use in the GUI code.
2019-02-11 14:08:04 -08:00

283 lines
9.5 KiB
C++

// Copyright (c) 2009-2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <psbt.h>
#include <util/strencodings.h>
PartiallySignedTransaction::PartiallySignedTransaction(const CMutableTransaction& tx) : tx(tx)
{
inputs.resize(tx.vin.size());
outputs.resize(tx.vout.size());
}
bool PartiallySignedTransaction::IsNull() const
{
return !tx && inputs.empty() && outputs.empty() && unknown.empty();
}
bool PartiallySignedTransaction::Merge(const PartiallySignedTransaction& psbt)
{
// Prohibited to merge two PSBTs over different transactions
if (tx->GetHash() != psbt.tx->GetHash()) {
return false;
}
for (unsigned int i = 0; i < inputs.size(); ++i) {
inputs[i].Merge(psbt.inputs[i]);
}
for (unsigned int i = 0; i < outputs.size(); ++i) {
outputs[i].Merge(psbt.outputs[i]);
}
unknown.insert(psbt.unknown.begin(), psbt.unknown.end());
return true;
}
bool PartiallySignedTransaction::IsSane() const
{
for (PSBTInput input : inputs) {
if (!input.IsSane()) return false;
}
return true;
}
bool PSBTInput::IsNull() const
{
return !non_witness_utxo && witness_utxo.IsNull() && partial_sigs.empty() && unknown.empty() && hd_keypaths.empty() && redeem_script.empty() && witness_script.empty();
}
void PSBTInput::FillSignatureData(SignatureData& sigdata) const
{
if (!final_script_sig.empty()) {
sigdata.scriptSig = final_script_sig;
sigdata.complete = true;
}
if (!final_script_witness.IsNull()) {
sigdata.scriptWitness = final_script_witness;
sigdata.complete = true;
}
if (sigdata.complete) {
return;
}
sigdata.signatures.insert(partial_sigs.begin(), partial_sigs.end());
if (!redeem_script.empty()) {
sigdata.redeem_script = redeem_script;
}
if (!witness_script.empty()) {
sigdata.witness_script = witness_script;
}
for (const auto& key_pair : hd_keypaths) {
sigdata.misc_pubkeys.emplace(key_pair.first.GetID(), key_pair);
}
}
void PSBTInput::FromSignatureData(const SignatureData& sigdata)
{
if (sigdata.complete) {
partial_sigs.clear();
hd_keypaths.clear();
redeem_script.clear();
witness_script.clear();
if (!sigdata.scriptSig.empty()) {
final_script_sig = sigdata.scriptSig;
}
if (!sigdata.scriptWitness.IsNull()) {
final_script_witness = sigdata.scriptWitness;
}
return;
}
partial_sigs.insert(sigdata.signatures.begin(), sigdata.signatures.end());
if (redeem_script.empty() && !sigdata.redeem_script.empty()) {
redeem_script = sigdata.redeem_script;
}
if (witness_script.empty() && !sigdata.witness_script.empty()) {
witness_script = sigdata.witness_script;
}
for (const auto& entry : sigdata.misc_pubkeys) {
hd_keypaths.emplace(entry.second);
}
}
void PSBTInput::Merge(const PSBTInput& input)
{
if (!non_witness_utxo && input.non_witness_utxo) non_witness_utxo = input.non_witness_utxo;
if (witness_utxo.IsNull() && !input.witness_utxo.IsNull()) {
witness_utxo = input.witness_utxo;
non_witness_utxo = nullptr; // Clear out any non-witness utxo when we set a witness one.
}
partial_sigs.insert(input.partial_sigs.begin(), input.partial_sigs.end());
hd_keypaths.insert(input.hd_keypaths.begin(), input.hd_keypaths.end());
unknown.insert(input.unknown.begin(), input.unknown.end());
if (redeem_script.empty() && !input.redeem_script.empty()) redeem_script = input.redeem_script;
if (witness_script.empty() && !input.witness_script.empty()) witness_script = input.witness_script;
if (final_script_sig.empty() && !input.final_script_sig.empty()) final_script_sig = input.final_script_sig;
if (final_script_witness.IsNull() && !input.final_script_witness.IsNull()) final_script_witness = input.final_script_witness;
}
bool PSBTInput::IsSane() const
{
// Cannot have both witness and non-witness utxos
if (!witness_utxo.IsNull() && non_witness_utxo) return false;
// If we have a witness_script or a scriptWitness, we must also have a witness utxo
if (!witness_script.empty() && witness_utxo.IsNull()) return false;
if (!final_script_witness.IsNull() && witness_utxo.IsNull()) return false;
return true;
}
void PSBTOutput::FillSignatureData(SignatureData& sigdata) const
{
if (!redeem_script.empty()) {
sigdata.redeem_script = redeem_script;
}
if (!witness_script.empty()) {
sigdata.witness_script = witness_script;
}
for (const auto& key_pair : hd_keypaths) {
sigdata.misc_pubkeys.emplace(key_pair.first.GetID(), key_pair);
}
}
void PSBTOutput::FromSignatureData(const SignatureData& sigdata)
{
if (redeem_script.empty() && !sigdata.redeem_script.empty()) {
redeem_script = sigdata.redeem_script;
}
if (witness_script.empty() && !sigdata.witness_script.empty()) {
witness_script = sigdata.witness_script;
}
for (const auto& entry : sigdata.misc_pubkeys) {
hd_keypaths.emplace(entry.second);
}
}
bool PSBTOutput::IsNull() const
{
return redeem_script.empty() && witness_script.empty() && hd_keypaths.empty() && unknown.empty();
}
void PSBTOutput::Merge(const PSBTOutput& output)
{
hd_keypaths.insert(output.hd_keypaths.begin(), output.hd_keypaths.end());
unknown.insert(output.unknown.begin(), output.unknown.end());
if (redeem_script.empty() && !output.redeem_script.empty()) redeem_script = output.redeem_script;
if (witness_script.empty() && !output.witness_script.empty()) witness_script = output.witness_script;
}
bool PSBTInputSigned(PSBTInput& input)
{
return !input.final_script_sig.empty() || !input.final_script_witness.IsNull();
}
bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index, int sighash)
{
PSBTInput& input = psbt.inputs.at(index);
const CMutableTransaction& tx = *psbt.tx;
if (PSBTInputSigned(input)) {
return true;
}
// Fill SignatureData with input info
SignatureData sigdata;
input.FillSignatureData(sigdata);
// Get UTXO
bool require_witness_sig = false;
CTxOut utxo;
// Verify input sanity, which checks that at most one of witness or non-witness utxos is provided.
if (!input.IsSane()) {
return false;
}
if (input.non_witness_utxo) {
// If we're taking our information from a non-witness UTXO, verify that it matches the prevout.
COutPoint prevout = tx.vin[index].prevout;
if (input.non_witness_utxo->GetHash() != prevout.hash) {
return false;
}
utxo = input.non_witness_utxo->vout[prevout.n];
} else if (!input.witness_utxo.IsNull()) {
utxo = input.witness_utxo;
// When we're taking our information from a witness UTXO, we can't verify it is actually data from
// the output being spent. This is safe in case a witness signature is produced (which includes this
// information directly in the hash), but not for non-witness signatures. Remember that we require
// a witness signature in this situation.
require_witness_sig = true;
} else {
return false;
}
MutableTransactionSignatureCreator creator(&tx, index, utxo.nValue, sighash);
sigdata.witness = false;
bool sig_complete = ProduceSignature(provider, creator, utxo.scriptPubKey, sigdata);
// Verify that a witness signature was produced in case one was required.
if (require_witness_sig && !sigdata.witness) return false;
input.FromSignatureData(sigdata);
// If we have a witness signature, use the smaller witness UTXO.
if (sigdata.witness) {
input.witness_utxo = utxo;
input.non_witness_utxo = nullptr;
}
return sig_complete;
}
bool FinalizePSBT(PartiallySignedTransaction& psbtx)
{
// Finalize input signatures -- in case we have partial signatures that add up to a complete
// signature, but have not combined them yet (e.g. because the combiner that created this
// PartiallySignedTransaction did not understand them), this will combine them into a final
// script.
bool complete = true;
for (unsigned int i = 0; i < psbtx.tx->vin.size(); ++i) {
complete &= SignPSBTInput(DUMMY_SIGNING_PROVIDER, psbtx, i, SIGHASH_ALL);
}
return complete;
}
bool FinalizeAndExtractPSBT(PartiallySignedTransaction& psbtx, CMutableTransaction& result)
{
// It's not safe to extract a PSBT that isn't finalized, and there's no easy way to check
// whether a PSBT is finalized without finalizing it, so we just do this.
if (!FinalizePSBT(psbtx)) {
return false;
}
result = *psbtx.tx;
for (unsigned int i = 0; i < result.vin.size(); ++i) {
result.vin[i].scriptSig = psbtx.inputs[i].final_script_sig;
result.vin[i].scriptWitness = psbtx.inputs[i].final_script_witness;
}
return true;
}
bool CombinePSBTs(PartiallySignedTransaction& out, TransactionError& error, const std::vector<PartiallySignedTransaction>& psbtxs)
{
out = psbtxs[0]; // Copy the first one
// Merge
for (auto it = std::next(psbtxs.begin()); it != psbtxs.end(); ++it) {
if (!out.Merge(*it)) {
error = TransactionError::PSBT_MISMATCH;
return false;
}
}
if (!out.IsSane()) {
error = TransactionError::INVALID_PSBT;
return false;
}
return true;
}