miniscript/psbt/

finalizer.rs

// Written in 2020 by Sanket Kanjalkar <sanket1729@gmail.com>
// SPDX-License-Identifier: CC0-1.0

//! Partially-Signed Bitcoin Transactions
//!
//! This module implements the Finalizer and Extractor roles defined in
//! BIP 174, PSBT, described at
//! `https://github.com/bitcoin/bips/blob/master/bip-0174.mediawiki`
//!

use core::convert::TryFrom;
use core::mem;

use bitcoin::hashes::hash160;
use bitcoin::key::XOnlyPublicKey;
#[cfg(not(test))] // https://github.com/rust-lang/rust/issues/121684
use bitcoin::secp256k1;
use bitcoin::secp256k1::Secp256k1;
use bitcoin::sighash::Prevouts;
use bitcoin::taproot::LeafVersion;
use bitcoin::{PublicKey, Script, ScriptBuf, TxOut, Witness};

use super::{sanity_check, Error, InputError, Psbt, PsbtInputSatisfier};
use crate::prelude::*;
use crate::util::witness_size;
use crate::{
    interpreter, BareCtx, Descriptor, Legacy, Miniscript, Satisfier, Segwitv0, SigType, Tap,
    ToPublicKey,
};

// Satisfy the taproot descriptor. It is not possible to infer the complete
// descriptor from psbt because the information about all the scripts might not
// be present. Also, currently the spec does not support hidden branches, so
// inferring a descriptor is not possible
fn construct_tap_witness(
    spk: &Script,
    sat: &PsbtInputSatisfier,
    allow_mall: bool,
) -> Result<Vec<Vec<u8>>, InputError> {
    // When miniscript tries to finalize the PSBT, it doesn't have the full descriptor (which contained a pkh() fragment)
    // and instead resorts to parsing the raw script sig, which is translated into a "expr_raw_pkh" internally.
    let mut map: BTreeMap<hash160::Hash, bitcoin::key::XOnlyPublicKey> = BTreeMap::new();
    let psbt_inputs = &sat.psbt.inputs;
    for psbt_input in psbt_inputs {
        // We need to satisfy or dissatisfy any given key. `tap_key_origin` is the only field of PSBT Input which consist of
        // all the keys added on a descriptor and thus we get keys from it.
        let public_keys = psbt_input.tap_key_origins.keys();
        for key in public_keys {
            let bitcoin_key = *key;
            let hash = bitcoin_key.to_pubkeyhash(SigType::Schnorr);
            map.insert(hash, bitcoin_key);
        }
    }
    assert!(spk.is_p2tr());

    // try the key spend path firsti
    if let Some(ref key) = sat.psbt_input().tap_internal_key {
        if let Some(sig) =
            <PsbtInputSatisfier as Satisfier<XOnlyPublicKey>>::lookup_tap_key_spend_sig(sat, key)
        {
            return Ok(vec![sig.to_vec()]);
        }
    }
    // Next script spends
    let (mut min_wit, mut min_wit_len) = (None, None);
    if let Some(block_map) =
        <PsbtInputSatisfier as Satisfier<XOnlyPublicKey>>::lookup_tap_control_block_map(sat)
    {
        for (control_block, (script, ver)) in block_map {
            if *ver != LeafVersion::TapScript {
                // We don't know how to satisfy non default version scripts yet
                continue;
            }
            let ms = match Miniscript::<XOnlyPublicKey, Tap>::decode_consensus(script) {
                Ok(ms) => ms.substitute_raw_pkh(&map),
                Err(..) => continue, // try another script
            };
            let mut wit = if allow_mall {
                match ms.satisfy_malleable(sat) {
                    Ok(ms) => ms,
                    Err(..) => continue,
                }
            } else {
                match ms.satisfy(sat) {
                    Ok(ms) => ms,
                    Err(..) => continue,
                }
            };
            wit.push(ms.encode().into_bytes());
            wit.push(control_block.serialize());
            let wit_len = Some(witness_size(&wit));
            if min_wit_len.is_some() && wit_len > min_wit_len {
                continue;
            } else {
                // store the minimum
                min_wit = Some(wit);
                min_wit_len = wit_len;
            }
        }
        min_wit.ok_or(InputError::CouldNotSatisfyTr)
    } else {
        // No control blocks found
        Err(InputError::CouldNotSatisfyTr)
    }
}

// Get the scriptpubkey for the psbt input
pub(super) fn get_scriptpubkey(psbt: &Psbt, index: usize) -> Result<ScriptBuf, InputError> {
    get_utxo(psbt, index).map(|utxo| utxo.script_pubkey.clone())
}

// Get the spending utxo for this psbt input
pub(super) fn get_utxo(psbt: &Psbt, index: usize) -> Result<&bitcoin::TxOut, InputError> {
    let inp = &psbt.inputs[index];
    let utxo = if let Some(ref witness_utxo) = inp.witness_utxo {
        witness_utxo
    } else if let Some(ref non_witness_utxo) = inp.non_witness_utxo {
        let vout = psbt.unsigned_tx.input[index].previous_output.vout;
        &non_witness_utxo.output[vout as usize]
    } else {
        return Err(InputError::MissingUtxo);
    };
    Ok(utxo)
}

/// Get the Prevouts for the psbt
pub(super) fn prevouts(psbt: &Psbt) -> Result<Vec<&bitcoin::TxOut>, super::Error> {
    let mut utxos = vec![];
    for i in 0..psbt.inputs.len() {
        let utxo_ref = get_utxo(psbt, i).map_err(|e| Error::InputError(e, i))?;
        utxos.push(utxo_ref);
    }
    Ok(utxos)
}

// Create a descriptor from unfinalized PSBT input.
// Panics on out of bound input index for psbt
// Also sanity checks that the witness script and
// redeem script are consistent with the script pubkey.
// Does *not* check signatures
// We parse the insane version while satisfying because
// we want to move the script is probably already created
// and we want to satisfy it in any way possible.
fn get_descriptor(psbt: &Psbt, index: usize) -> Result<Descriptor<PublicKey>, InputError> {
    let mut map: BTreeMap<hash160::Hash, PublicKey> = BTreeMap::new();
    let psbt_inputs = &psbt.inputs;
    for psbt_input in psbt_inputs {
        // Use BIP32 Derviation to get set of all possible keys.
        let public_keys = psbt_input.bip32_derivation.keys();
        for key in public_keys {
            let bitcoin_key = bitcoin::PublicKey::new(*key);
            let hash = bitcoin_key.pubkey_hash().to_raw_hash();
            map.insert(hash, bitcoin_key);
        }
    }

    // Figure out Scriptpubkey
    let script_pubkey = get_scriptpubkey(psbt, index)?;
    let inp = &psbt.inputs[index];
    // 1. `PK`: creates a `Pk` descriptor(does not check if partial sig is given)
    if script_pubkey.is_p2pk() {
        let script_pubkey_len = script_pubkey.len();
        let pk_bytes = &script_pubkey.to_bytes();
        match bitcoin::PublicKey::from_slice(&pk_bytes[1..script_pubkey_len - 1]) {
            Ok(pk) => Ok(Descriptor::new_pk(pk)),
            Err(e) => Err(InputError::from(e)),
        }
    } else if script_pubkey.is_p2pkh() {
        // 2. `Pkh`: creates a `PkH` descriptor if partial_sigs has the corresponding pk
        let partial_sig_contains_pk = inp.partial_sigs.iter().find(|&(&pk, _sig)| {
            // Indirect way to check the equivalence of pubkey-hashes.
            // Create a pubkey hash and check if they are the same.
            // THIS IS A BUG AND *WILL* PRODUCE WRONG SATISFACTIONS FOR UNCOMPRESSED KEYS
            // Partial sigs loses the compressed flag that is necessary
            // TODO: See https://github.com/rust-bitcoin/rust-bitcoin/pull/836
            // The type checker will fail again after we update to 0.28 and this can be removed
            let addr = bitcoin::Address::p2pkh(pk, bitcoin::Network::Bitcoin);
            *script_pubkey == addr.script_pubkey()
        });
        match partial_sig_contains_pk {
            Some((pk, _sig)) => Descriptor::new_pkh(*pk).map_err(InputError::from),
            None => Err(InputError::MissingPubkey),
        }
    } else if script_pubkey.is_p2wpkh() {
        // 3. `Wpkh`: creates a `wpkh` descriptor if the partial sig has corresponding pk.
        let partial_sig_contains_pk = inp.partial_sigs.iter().find(|&(&pk, _sig)| {
            match bitcoin::key::CompressedPublicKey::try_from(pk) {
                Ok(compressed) => {
                    // Indirect way to check the equivalence of pubkey-hashes.
                    // Create a pubkey hash and check if they are the same.
                    let addr = bitcoin::Address::p2wpkh(&compressed, bitcoin::Network::Bitcoin);
                    *script_pubkey == addr.script_pubkey()
                }
                Err(_) => false,
            }
        });
        match partial_sig_contains_pk {
            Some((pk, _sig)) => Ok(Descriptor::new_wpkh(*pk)?),
            None => Err(InputError::MissingPubkey),
        }
    } else if script_pubkey.is_p2wsh() {
        // 4. `Wsh`: creates a `Wsh` descriptor
        if inp.redeem_script.is_some() {
            return Err(InputError::NonEmptyRedeemScript);
        }
        if let Some(ref witness_script) = inp.witness_script {
            if witness_script.to_p2wsh() != *script_pubkey {
                return Err(InputError::InvalidWitnessScript {
                    witness_script: witness_script.clone(),
                    p2wsh_expected: script_pubkey.clone(),
                });
            }
            let ms = Miniscript::<bitcoin::PublicKey, Segwitv0>::decode_consensus(witness_script)?;
            Ok(Descriptor::new_wsh(ms.substitute_raw_pkh(&map))?)
        } else {
            Err(InputError::MissingWitnessScript)
        }
    } else if script_pubkey.is_p2sh() {
        match inp.redeem_script {
            None => Err(InputError::MissingRedeemScript),
            Some(ref redeem_script) => {
                if redeem_script.to_p2sh() != *script_pubkey {
                    return Err(InputError::InvalidRedeemScript {
                        redeem: redeem_script.clone(),
                        p2sh_expected: script_pubkey.clone(),
                    });
                }
                if redeem_script.is_p2wsh() {
                    // 5. `ShWsh` case
                    if let Some(ref witness_script) = inp.witness_script {
                        if witness_script.to_p2wsh() != *redeem_script {
                            return Err(InputError::InvalidWitnessScript {
                                witness_script: witness_script.clone(),
                                p2wsh_expected: redeem_script.clone(),
                            });
                        }
                        let ms = Miniscript::<bitcoin::PublicKey, Segwitv0>::decode_consensus(
                            witness_script,
                        )?;
                        Ok(Descriptor::new_sh_wsh(ms.substitute_raw_pkh(&map))?)
                    } else {
                        Err(InputError::MissingWitnessScript)
                    }
                } else if redeem_script.is_p2wpkh() {
                    // 6. `ShWpkh` case
                    let partial_sig_contains_pk = inp.partial_sigs.iter().find(|&(&pk, _sig)| {
                        match bitcoin::key::CompressedPublicKey::try_from(pk) {
                            Ok(compressed) => {
                                let addr = bitcoin::Address::p2wpkh(
                                    &compressed,
                                    bitcoin::Network::Bitcoin,
                                );
                                *redeem_script == addr.script_pubkey()
                            }
                            Err(_) => false,
                        }
                    });
                    match partial_sig_contains_pk {
                        Some((pk, _sig)) => Ok(Descriptor::new_sh_wpkh(*pk)?),
                        None => Err(InputError::MissingPubkey),
                    }
                } else {
                    //7. regular p2sh
                    if inp.witness_script.is_some() {
                        return Err(InputError::NonEmptyWitnessScript);
                    }
                    if let Some(ref redeem_script) = inp.redeem_script {
                        let ms = Miniscript::<bitcoin::PublicKey, Legacy>::decode_consensus(
                            redeem_script,
                        )?;
                        Ok(Descriptor::new_sh(ms)?)
                    } else {
                        Err(InputError::MissingWitnessScript)
                    }
                }
            }
        }
    } else {
        // 8. Bare case
        if inp.witness_script.is_some() {
            return Err(InputError::NonEmptyWitnessScript);
        }
        if inp.redeem_script.is_some() {
            return Err(InputError::NonEmptyRedeemScript);
        }
        let ms = Miniscript::<bitcoin::PublicKey, BareCtx>::decode_consensus(&script_pubkey)?;
        Ok(Descriptor::new_bare(ms.substitute_raw_pkh(&map))?)
    }
}

/// Interprets all psbt inputs and checks whether the
/// script is correctly interpreted according to the context.
///
/// The psbt must have included final script sig and final witness.
/// In other words, this checks whether the finalized psbt interprets
/// correctly
pub fn interpreter_check<C: secp256k1::Verification>(
    psbt: &Psbt,
    secp: &Secp256k1<C>,
) -> Result<(), Error> {
    let utxos = prevouts(psbt)?;
    let utxos = &Prevouts::All(&utxos);
    for (index, input) in psbt.inputs.iter().enumerate() {
        let empty_script_sig = ScriptBuf::new();
        let empty_witness = Witness::default();
        let script_sig = input.final_script_sig.as_ref().unwrap_or(&empty_script_sig);
        let witness = input
            .final_script_witness
            .as_ref()
            .map(|wit_slice| Witness::from_slice(&wit_slice.to_vec())) // TODO: Update rust-bitcoin psbt API to use witness
            .unwrap_or(empty_witness);

        interpreter_inp_check(psbt, secp, index, utxos, &witness, script_sig)?;
    }
    Ok(())
}

// Run the miniscript interpreter on a single psbt input
fn interpreter_inp_check<C: secp256k1::Verification, T: Borrow<TxOut>>(
    psbt: &Psbt,
    secp: &Secp256k1<C>,
    index: usize,
    utxos: &Prevouts<T>,
    witness: &Witness,
    script_sig: &Script,
) -> Result<(), Error> {
    let spk = get_scriptpubkey(psbt, index).map_err(|e| Error::InputError(e, index))?;

    // Now look at all the satisfied constraints. If everything is filled in
    // corrected, there should be no errors
    // Interpreter check
    {
        let cltv = psbt.unsigned_tx.lock_time;
        let csv = psbt.unsigned_tx.input[index].sequence;
        let interpreter =
            interpreter::Interpreter::from_txdata(&spk, script_sig, witness, csv, cltv)
                .map_err(|e| Error::InputError(InputError::Interpreter(e), index))?;
        let iter = interpreter.iter(secp, &psbt.unsigned_tx, index, utxos);
        if let Some(error) = iter.filter_map(Result::err).next() {
            return Err(Error::InputError(InputError::Interpreter(error), index));
        };
    }
    Ok(())
}

/// Finalize the psbt.
///
/// This function takes in a mutable reference to psbt
/// and populates the final_witness and final_scriptsig
/// of the psbt assuming all of the inputs are miniscript as per BIP174.
/// If any of the inputs is not miniscript, this returns a parsing error
/// For satisfaction of individual inputs, use the satisfy API.
/// This function also performs a sanity interpreter check on the
/// finalized psbt which involves checking the signatures/ preimages/timelocks.
/// The functions fails it is not possible to satisfy any of the inputs non-malleably
/// See [finalize_mall] if you want to allow malleable satisfactions
#[deprecated(since = "7.0.0", note = "Please use PsbtExt::finalize instead")]
pub fn finalize<C: secp256k1::Verification>(
    psbt: &mut Psbt,
    secp: &Secp256k1<C>,
) -> Result<(), super::Error> {
    finalize_helper(psbt, secp, false)
}

/// Same as [finalize], but allows for malleable satisfactions
pub fn finalize_mall<C: secp256k1::Verification>(
    psbt: &mut Psbt,
    secp: &Secp256k1<C>,
) -> Result<(), super::Error> {
    finalize_helper(psbt, secp, true)
}

pub fn finalize_helper<C: secp256k1::Verification>(
    psbt: &mut Psbt,
    secp: &Secp256k1<C>,
    allow_mall: bool,
) -> Result<(), super::Error> {
    sanity_check(psbt)?;

    // Actually construct the witnesses
    for index in 0..psbt.inputs.len() {
        finalize_input(psbt, index, secp, allow_mall)?;
    }
    // Interpreter is already run inside finalize_input for each input
    Ok(())
}

// Helper function to obtain psbt final_witness/final_script_sig.
// Does not add fields to the psbt, only returns the values.
fn finalize_input_helper<C: secp256k1::Verification>(
    psbt: &Psbt,
    index: usize,
    secp: &Secp256k1<C>,
    allow_mall: bool,
) -> Result<(Witness, ScriptBuf), super::Error> {
    let (witness, script_sig) = {
        let spk = get_scriptpubkey(psbt, index).map_err(|e| Error::InputError(e, index))?;
        let sat = PsbtInputSatisfier::new(psbt, index);

        if spk.is_p2tr() {
            // Deal with tr case separately, unfortunately we cannot infer the full descriptor for Tr
            let wit = construct_tap_witness(&spk, &sat, allow_mall)
                .map_err(|e| Error::InputError(e, index))?;
            (wit, ScriptBuf::new())
        } else {
            // Get a descriptor for this input.
            let desc = get_descriptor(psbt, index).map_err(|e| Error::InputError(e, index))?;

            //generate the satisfaction witness and scriptsig
            let sat = PsbtInputSatisfier::new(psbt, index);
            if !allow_mall {
                desc.get_satisfaction(sat)
            } else {
                desc.get_satisfaction_mall(sat)
            }
            .map_err(|e| Error::InputError(InputError::MiniscriptError(e), index))?
        }
    };

    let witness = bitcoin::Witness::from_slice(&witness);
    let utxos = prevouts(psbt)?;
    let utxos = &Prevouts::All(&utxos);
    interpreter_inp_check(psbt, secp, index, utxos, &witness, &script_sig)?;

    Ok((witness, script_sig))
}

pub(super) fn finalize_input<C: secp256k1::Verification>(
    psbt: &mut Psbt,
    index: usize,
    secp: &Secp256k1<C>,
    allow_mall: bool,
) -> Result<(), super::Error> {
    // Preserve previously finalized inputs
    if psbt.inputs[index].final_script_sig.is_some()
        || psbt.inputs[index].final_script_witness.is_some()
    {
        return Ok(());
    }

    let (witness, script_sig) = finalize_input_helper(psbt, index, secp, allow_mall)?;

    // Now mutate the psbt input. Note that we cannot error after this point.
    // If the input is mutated, it means that the finalization succeeded.
    {
        let original = mem::take(&mut psbt.inputs[index]);
        let input = &mut psbt.inputs[index];
        input.non_witness_utxo = original.non_witness_utxo;
        input.witness_utxo = original.witness_utxo;
        input.final_script_sig = if script_sig.is_empty() {
            None
        } else {
            Some(script_sig)
        };
        input.final_script_witness = if witness.is_empty() {
            None
        } else {
            Some(witness)
        };
    }

    Ok(())
}

#[cfg(test)]
mod tests {
    use bitcoin::{absolute, transaction, Transaction, TxIn};
    use hex;

    use super::*;
    use crate::psbt::PsbtExt;

    #[test]
    fn tests_from_bip174() {
        let mut psbt = Psbt::deserialize(&hex::decode_to_vec("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").unwrap()).unwrap();

        let secp = Secp256k1::verification_only();
        psbt.finalize_mut(&secp).unwrap();

        let expected = Psbt::deserialize(&hex::decode_to_vec("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").unwrap()).unwrap();
        assert_eq!(psbt, expected);
    }

    #[test]
    fn finalize_skips_already_finalized_input() {
        let tx = Transaction {
            version: transaction::Version::ONE,
            lock_time: absolute::LockTime::ZERO,
            input: vec![TxIn::default()],
            output: vec![],
        };
        let mut psbt = Psbt::from_unsigned_tx(tx).unwrap();
        psbt.inputs[0].final_script_witness = Some(Witness::from_slice(&[vec![1]]));

        let expected_input = psbt.inputs[0].clone();
        let secp = Secp256k1::verification_only();

        psbt.finalize_mut(&secp).unwrap();

        assert_eq!(psbt.inputs[0], expected_input);
    }
}