Use new PSBT signing API in example
We have a PSBT example that includes a custom signing module, we can remove that now and use the new PSBT signing API.
This commit is contained in:
Tobin C. Harding
parent
d2367fb187
commit
dd8730e14f
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@ -28,27 +28,24 @@
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//! `bt listunspent`
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//! `bt listunspent`
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//!
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//!
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use std::boxed::Box;
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use std::collections::BTreeMap;
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use std::collections::BTreeMap;
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use std::fmt;
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use std::fmt;
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use std::str::FromStr;
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use std::str::FromStr;
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use bitcoin::consensus::encode;
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use bitcoin::consensus::encode;
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use bitcoin::hashes::hex::{self, FromHex};
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use bitcoin::hashes::hex::FromHex;
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use bitcoin::locktime::absolute;
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use bitcoin::locktime::absolute;
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use bitcoin::secp256k1::{Secp256k1, Signing, Verification};
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use bitcoin::secp256k1::{Secp256k1, Signing, Verification};
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use bitcoin::util::amount::ParseAmountError;
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use bitcoin::util::bip32::{
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use bitcoin::util::bip32::{
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self, ChildNumber, DerivationPath, ExtendedPrivKey, ExtendedPubKey, Fingerprint,
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ChildNumber, DerivationPath, ExtendedPrivKey, ExtendedPubKey, Fingerprint, IntoDerivationPath,
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IntoDerivationPath,
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};
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};
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use bitcoin::util::psbt::{self, Input, Psbt, PsbtSighashType};
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use bitcoin::util::psbt::{self, Input, Psbt, PsbtSighashType};
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use bitcoin::{
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use bitcoin::{
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address, Address, Amount, Network, OutPoint, PrivateKey, PublicKey, Script, Sequence,
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Address, Amount, Network, OutPoint, PublicKey, Script, Sequence, Transaction, TxIn, TxOut,
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Transaction, TxIn, TxOut, Txid, Witness,
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Txid, Witness,
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};
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};
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use self::psbt_sign::*;
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type Result<T> = std::result::Result<T, Error>;
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type Result<T> = std::result::Result<T, Error>;
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// Get this from the output of `bt dumpwallet <file>`.
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// Get this from the output of `bt dumpwallet <file>`.
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@ -141,34 +138,15 @@ impl ColdStorage {
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/// Signs `psbt` with this signer.
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/// Signs `psbt` with this signer.
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fn sign_psbt<C: Signing>(&self, secp: &Secp256k1<C>, mut psbt: Psbt) -> Result<Psbt> {
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fn sign_psbt<C: Signing>(&self, secp: &Secp256k1<C>, mut psbt: Psbt) -> Result<Psbt> {
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let sk = self.private_key_to_sign(secp, &psbt.inputs[0])?;
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match psbt.sign(&self.master_xpriv, secp) {
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psbt_sign::sign(&mut psbt, &sk, 0, secp)?;
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Ok(keys) => assert_eq!(keys.len(), 1),
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Err((_, e)) => {
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let e = e.get(&0).expect("at least one error");
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return Err(e.clone().into());
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}
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};
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Ok(psbt)
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Ok(psbt)
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}
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}
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/// Returns the private key required to sign `input` if we have it.
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fn private_key_to_sign<C: Signing>(
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&self,
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secp: &Secp256k1<C>,
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input: &Input,
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) -> Result<PrivateKey> {
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match input.bip32_derivation.iter().next() {
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Some((pk, (fingerprint, path))) => {
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if *fingerprint != self.master_fingerprint() {
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return Err(Error::WrongFingerprint);
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}
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let sk = self.master_xpriv.derive_priv(secp, &path)?.to_priv();
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if *pk != sk.public_key(secp).inner {
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return Err(Error::WrongPubkey);
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}
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Ok(sk)
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}
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None => Err(Error::MissingBip32Derivation),
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}
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}
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}
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}
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/// An example of an watch-only online wallet.
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/// An example of an watch-only online wallet.
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@ -247,7 +225,7 @@ impl WatchOnly {
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map.insert(pk.inner, (fingerprint, path));
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map.insert(pk.inner, (fingerprint, path));
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input.bip32_derivation = map;
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input.bip32_derivation = map;
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let ty = PsbtSighashType::from_str("SIGHASH_ALL").map_err(|_| Error::SighashTypeParse)?;
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let ty = PsbtSighashType::from_str("SIGHASH_ALL")?;
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input.sighash_type = Some(ty);
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input.sighash_type = Some(ty);
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psbt.inputs = vec![input];
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psbt.inputs = vec![input];
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@ -260,11 +238,10 @@ impl WatchOnly {
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use bitcoin::util::psbt::serialize::Serialize;
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use bitcoin::util::psbt::serialize::Serialize;
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if psbt.inputs.is_empty() {
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if psbt.inputs.is_empty() {
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return Err(Error::InputsEmpty);
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return Err(psbt::SignError::MissingInputUtxo.into());
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}
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}
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let sigs: Vec<_> = psbt.inputs[0].partial_sigs.values().collect();
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let sigs: Vec<_> = psbt.inputs[0].partial_sigs.values().collect();
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let mut script_witness: Witness = Witness::new();
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let mut script_witness: Witness = Witness::new();
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script_witness.push(&sigs[0].serialize());
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script_witness.push(&sigs[0].serialize());
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script_witness.push(self.input_xpub.to_pub().serialize());
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script_witness.push(self.input_xpub.to_pub().serialize());
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@ -313,301 +290,12 @@ fn previous_output() -> TxOut {
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TxOut { value: amount.to_sat(), script_pubkey }
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TxOut { value: amount.to_sat(), script_pubkey }
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}
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}
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#[derive(Clone, Debug, PartialEq, Eq)]
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struct Error(Box<dyn std::error::Error>);
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enum Error {
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/// Bip32 error.
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impl<T: std::error::Error + 'static> From<T> for Error {
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Bip32(bip32::Error),
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fn from(e: T) -> Self { Error(Box::new(e)) }
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/// PSBT error.
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Psbt(psbt::Error),
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/// PSBT sighash error.
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PsbtSighash(SighashError),
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/// Bitcoin_hashes hex error.
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Hex(hex::Error),
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/// Address error.
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Address(address::Error),
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/// Parse amount error.
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ParseAmount(ParseAmountError),
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/// Parsing sighash type string failed.
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SighashTypeParse,
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/// PSBT inputs field is empty.
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InputsEmpty,
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/// BIP32 data missing.
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MissingBip32Derivation,
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/// Fingerprint does not match that in input.
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WrongFingerprint,
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/// Pubkey for derivation path does not match that in input.
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WrongPubkey,
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}
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}
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impl std::error::Error for Error {
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impl fmt::Debug for Error {
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fn source(&self) -> Option<&(dyn std::error::Error + 'static)> { None }
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { fmt::Debug::fmt(&self.0, f) }
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}
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impl fmt::Display for Error {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { write!(f, "{:?}", self) }
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}
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impl From<bip32::Error> for Error {
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fn from(e: bip32::Error) -> Error { Error::Bip32(e) }
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}
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impl From<psbt::Error> for Error {
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fn from(e: psbt::Error) -> Error { Error::Psbt(e) }
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}
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impl From<SighashError> for Error {
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fn from(e: SighashError) -> Error { Error::PsbtSighash(e) }
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}
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impl From<hex::Error> for Error {
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fn from(e: hex::Error) -> Error { Error::Hex(e) }
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}
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impl From<address::Error> for Error {
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fn from(e: address::Error) -> Error { Error::Address(e) }
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}
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impl From<ParseAmountError> for Error {
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fn from(e: ParseAmountError) -> Error { Error::ParseAmount(e) }
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}
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/// This module implements signing a PSBT. It is based on code in `rust-miniscript` with a bit of a
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/// look at `bdk` as well. Since this example only uses ECDSA signatures the signing code is
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/// sufficient however before we can merge this into the main `rust-bitcoin` crate we need to handle
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/// taproot as well. See PR: https://github.com/rust-bitcoin/rust-bitcoin/pull/957
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///
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/// All functions that take a `psbt` argument should be implemented on `Psbt` and use `self` instead.
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mod psbt_sign {
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use std::fmt;
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use std::ops::Deref;
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use bitcoin::psbt::{Input, Prevouts, Psbt, PsbtSighashType};
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use bitcoin::sighash::{self, EcdsaSighashType, SchnorrSighashType, SighashCache};
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use bitcoin::util::taproot::TapLeafHash;
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use bitcoin::{EcdsaSig, EcdsaSigError, PrivateKey, Script, Transaction, TxOut};
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use secp256k1::{Message, Secp256k1, Signing};
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/// Signs the input at `input_index` with private key `sk`.
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pub fn sign<C: Signing>(
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psbt: &mut Psbt,
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sk: &PrivateKey,
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input_index: usize,
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secp: &Secp256k1<C>,
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) -> Result<(), SighashError> {
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check_index_is_within_bounds(psbt, input_index)?;
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let mut cache = SighashCache::new(&psbt.unsigned_tx);
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let (msg, sighash_ty) = sighash(psbt, input_index, &mut cache, None)?;
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let sig = secp.sign_ecdsa(&msg, &sk.inner);
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let mut final_signature = Vec::with_capacity(75);
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final_signature.extend_from_slice(&sig.serialize_der());
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final_signature.push(sighash_ty.to_u32() as u8);
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let pk = sk.public_key(secp);
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psbt.inputs[input_index].partial_sigs.insert(pk, EcdsaSig::from_slice(&final_signature)?);
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Ok(())
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}
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/// Returns the sighash message to sign along with the sighash type.
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fn sighash<T: Deref<Target = Transaction>>(
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psbt: &Psbt,
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input_index: usize,
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cache: &mut SighashCache<T>,
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tapleaf_hash: Option<TapLeafHash>,
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) -> Result<(Message, PsbtSighashType), SighashError> {
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check_index_is_within_bounds(psbt, input_index)?;
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let input = &psbt.inputs[input_index];
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let prevouts = prevouts(psbt)?;
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let utxo = spend_utxo(psbt, input_index)?;
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let script = utxo.script_pubkey.clone(); // scriptPubkey for input spend utxo.
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if script.is_v1_p2tr() {
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return taproot_sighash(input, prevouts, input_index, cache, tapleaf_hash);
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}
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let hash_ty = input
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.sighash_type
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.map(|ty| ty.ecdsa_hash_ty())
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.unwrap_or(Ok(EcdsaSighashType::All))
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.map_err(|_| SighashError::InvalidSighashType)?; // Only support standard sighash types.
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let is_wpkh = script.is_v0_p2wpkh();
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let is_wsh = script.is_v0_p2wsh();
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let is_nested_wpkh = script.is_p2sh()
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&& input.redeem_script.as_ref().map(|s| s.is_v0_p2wpkh()).unwrap_or(false);
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let is_nested_wsh = script.is_p2sh()
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&& input.redeem_script.as_ref().map(|x| x.is_v0_p2wsh()).unwrap_or(false);
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let is_segwit = is_wpkh || is_wsh || is_nested_wpkh || is_nested_wsh;
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let sighash = if is_segwit {
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if is_wpkh || is_nested_wpkh {
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let script_code = if is_wpkh {
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Script::p2wpkh_script_code(&script).ok_or(SighashError::NotWpkh)?
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} else {
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Script::p2wpkh_script_code(input.redeem_script.as_ref().expect("checked above"))
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.ok_or(SighashError::NotWpkh)?
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};
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cache.segwit_signature_hash(input_index, &script_code, utxo.value, hash_ty)?
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} else {
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let script_code =
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input.witness_script.as_ref().ok_or(SighashError::MissingWitnessScript)?;
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cache.segwit_signature_hash(input_index, script_code, utxo.value, hash_ty)?
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}
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} else {
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let script_code = if script.is_p2sh() {
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input.redeem_script.as_ref().ok_or(SighashError::MissingRedeemScript)?
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} else {
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&script
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};
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cache.legacy_signature_hash(input_index, script_code, hash_ty.to_u32())?
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};
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Ok((Message::from_slice(&sighash).expect("sighashes are 32 bytes"), hash_ty.into()))
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}
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/// Returns the prevouts for this PSBT.
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fn prevouts(psbt: &Psbt) -> Result<Vec<&TxOut>, SighashError> {
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let len = psbt.inputs.len();
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let mut utxos = Vec::with_capacity(len);
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for i in 0..len {
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utxos.push(spend_utxo(psbt, i)?);
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}
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Ok(utxos)
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}
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/// Returns the spending utxo for this PSBT's input at `input_index`.
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fn spend_utxo(psbt: &Psbt, input_index: usize) -> Result<&TxOut, SighashError> {
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check_index_is_within_bounds(psbt, input_index)?;
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let input = &psbt.inputs[input_index];
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let utxo = if let Some(witness_utxo) = &input.witness_utxo {
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witness_utxo
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} else if let Some(non_witness_utxo) = &input.non_witness_utxo {
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let vout = psbt.unsigned_tx.input[input_index].previous_output.vout;
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&non_witness_utxo.output[vout as usize]
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} else {
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return Err(SighashError::MissingSpendUtxo);
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};
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Ok(utxo)
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}
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/// Checks `input_index` is within bounds for the PSBT `inputs` array and
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/// for the PSBT `unsigned_tx` `input` array.
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fn check_index_is_within_bounds(psbt: &Psbt, input_index: usize) -> Result<(), SighashError> {
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if input_index >= psbt.inputs.len() {
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return Err(SighashError::IndexOutOfBounds(input_index, psbt.inputs.len()));
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}
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if input_index >= psbt.unsigned_tx.input.len() {
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return Err(SighashError::IndexOutOfBounds(input_index, psbt.unsigned_tx.input.len()));
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}
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Ok(())
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}
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/// Returns the sighash message and sighash type for this `input`.
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fn taproot_sighash<T: Deref<Target = Transaction>>(
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input: &Input,
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prevouts: Vec<&TxOut>,
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input_index: usize,
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cache: &mut SighashCache<T>,
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tapleaf_hash: Option<TapLeafHash>,
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) -> Result<(Message, PsbtSighashType), SighashError> {
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// Note that as per PSBT spec we should have access to spent utxos for the transaction. Even
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// if the transaction does not require SIGHASH_ALL, we create `Prevouts::All` for simplicity.
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let prevouts = Prevouts::All(&prevouts);
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let hash_ty = input
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.sighash_type
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.map(|ty| ty.schnorr_hash_ty())
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.unwrap_or(Ok(SchnorrSighashType::Default))
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.map_err(|_e| SighashError::InvalidSighashType)?;
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let sighash = match tapleaf_hash {
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Some(leaf_hash) => cache.taproot_script_spend_signature_hash(
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input_index,
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&prevouts,
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leaf_hash,
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hash_ty,
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)?,
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None => cache.taproot_key_spend_signature_hash(input_index, &prevouts, hash_ty)?,
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};
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let msg = Message::from_slice(&sighash).expect("sighashes are 32 bytes");
|
|
||||||
Ok((msg, hash_ty.into()))
|
|
||||||
}
|
|
||||||
|
|
||||||
/// Errors encountered while calculating the sighash message.
|
|
||||||
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone)]
|
|
||||||
pub enum SighashError {
|
|
||||||
/// Input index out of bounds (actual index, maximum index allowed).
|
|
||||||
IndexOutOfBounds(usize, usize),
|
|
||||||
/// Missing spending utxo.
|
|
||||||
MissingSpendUtxo,
|
|
||||||
/// Missing witness script.
|
|
||||||
MissingWitnessScript,
|
|
||||||
/// Missing Redeem script.
|
|
||||||
MissingRedeemScript,
|
|
||||||
/// Invalid Sighash type.
|
|
||||||
InvalidSighashType,
|
|
||||||
/// The `scriptPubkey` is not a P2WPKH script.
|
|
||||||
NotWpkh,
|
|
||||||
/// Sighash computation error.
|
|
||||||
SighashComputation(sighash::Error),
|
|
||||||
/// An ECDSA key-related error occurred.
|
|
||||||
EcdsaSig(EcdsaSigError),
|
|
||||||
}
|
|
||||||
|
|
||||||
impl fmt::Display for SighashError {
|
|
||||||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
||||||
match self {
|
|
||||||
SighashError::IndexOutOfBounds(ind, len) => {
|
|
||||||
write!(f, "index {}, psbt input len: {}", ind, len)
|
|
||||||
}
|
|
||||||
SighashError::MissingSpendUtxo => write!(f, "missing spend utxon in PSBT"),
|
|
||||||
SighashError::MissingWitnessScript => write!(f, "missing witness script"),
|
|
||||||
SighashError::MissingRedeemScript => write!(f, "missing redeem script"),
|
|
||||||
SighashError::InvalidSighashType => write!(f, "invalid sighash type"),
|
|
||||||
SighashError::NotWpkh => write!(f, "the scriptPubkey is not a P2WPKH script"),
|
|
||||||
// If merged into rust-bitcoin these two should use `write_err!`.
|
|
||||||
SighashError::SighashComputation(e) => write!(f, "sighash: {}", e),
|
|
||||||
SighashError::EcdsaSig(e) => write!(f, "ecdsa: {}", e),
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
impl From<sighash::Error> for SighashError {
|
|
||||||
fn from(e: sighash::Error) -> Self { SighashError::SighashComputation(e) }
|
|
||||||
}
|
|
||||||
|
|
||||||
impl From<EcdsaSigError> for SighashError {
|
|
||||||
fn from(e: EcdsaSigError) -> Self { SighashError::EcdsaSig(e) }
|
|
||||||
}
|
|
||||||
|
|
||||||
#[cfg(feature = "std")]
|
|
||||||
impl std::error::Error for SighashError {
|
|
||||||
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
|
|
||||||
use self::SighashError::*;
|
|
||||||
|
|
||||||
match self {
|
|
||||||
IndexOutOfBounds(_, _)
|
|
||||||
| MissingSpendUtxo
|
|
||||||
| MissingWitnessScript
|
|
||||||
| MissingRedeemScript
|
|
||||||
| InvalidSighashType
|
|
||||||
| NotWpkh => None,
|
|
||||||
SighashComputation(e) => Some(e),
|
|
||||||
EcdsaSig(e) => Some(e),
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
}
|
||||||
|
|
|
||||||
Loading…
Reference in New Issue