--- /dev/null
+// Bitcoin Dev Kit
+// Written in 2021 by Alekos Filini <alekos.filini@gmail.com>
+//
+// Copyright (c) 2020-2021 Bitcoin Dev Kit Developers
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use std::fmt;
+
+use bitcoin::consensus::serialize;
+use bitcoin::{OutPoint, Transaction, Txid};
+
+use crate::blockchain::Blockchain;
+use crate::database::Database;
+use crate::error::Error;
+
+/// Verify a transaction against the consensus rules
+///
+/// This function uses [`bitcoinconsensus`] to verify transactions by fetching the required data
+/// either from the [`Database`] or using the [`Blockchain`].
+///
+/// Depending on the [capabilities](crate::blockchain::Blockchain::get_capabilities) of the
+/// [`Blockchain`] backend, the method could fail when called with old "historical" transactions or
+/// with unconfirmed transactions that have been evicted from the backend's memory.
+pub fn verify_tx<D: Database, B: Blockchain>(
+ tx: &Transaction,
+ database: &D,
+ blockchain: &B,
+) -> Result<(), VerifyError> {
+ log::debug!("Verifying {}", tx.txid());
+
+ let serialized_tx = serialize(tx);
+
+ for (index, input) in tx.input.iter().enumerate() {
+ let prev_tx = if let Some(prev_tx) = database.get_raw_tx(&input.previous_output.txid)? {
+ prev_tx
+ } else if let Some(prev_tx) = blockchain.get_tx(&input.previous_output.txid)? {
+ prev_tx
+ } else {
+ return Err(VerifyError::MissingInputTx(input.previous_output.txid));
+ };
+
+ let spent_output = prev_tx
+ .output
+ .get(input.previous_output.vout as usize)
+ .ok_or(VerifyError::InvalidInput(input.previous_output))?;
+
+ bitcoinconsensus::verify(
+ &spent_output.script_pubkey.to_bytes(),
+ spent_output.value,
+ &serialized_tx,
+ index,
+ )?;
+ }
+
+ Ok(())
+}
+
+#[derive(Debug)]
+pub enum VerifyError {
+ MissingInputTx(Txid),
+ InvalidInput(OutPoint),
+
+ Consensus(bitcoinconsensus::Error),
+
+ Global(Box<Error>),
+}
+
+impl fmt::Display for VerifyError {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ write!(f, "{:?}", self)
+ }
+}
+
+impl std::error::Error for VerifyError {}
+
+impl From<Error> for VerifyError {
+ fn from(other: Error) -> Self {
+ VerifyError::Global(Box::new(other))
+ }
+}
+impl From<bitcoinconsensus::Error> for VerifyError {
+ fn from(other: bitcoinconsensus::Error) -> Self {
+ VerifyError::Consensus(other)
+ }
+}
+
+#[cfg(test)]
+mod test {
+ use std::collections::HashSet;
+
+ use bitcoin::consensus::encode::deserialize;
+ use bitcoin::hashes::hex::FromHex;
+ use bitcoin::{Transaction, Txid};
+
+ use crate::blockchain::{Blockchain, Capability, Progress};
+ use crate::database::{BatchDatabase, BatchOperations, MemoryDatabase};
+ use crate::FeeRate;
+
+ use super::*;
+
+ struct DummyBlockchain;
+
+ impl Blockchain for DummyBlockchain {
+ fn get_capabilities(&self) -> HashSet<Capability> {
+ Default::default()
+ }
+ fn setup<D: BatchDatabase, P: 'static + Progress>(
+ &self,
+ _stop_gap: Option<usize>,
+ _database: &mut D,
+ _progress_update: P,
+ ) -> Result<(), Error> {
+ Ok(())
+ }
+ fn get_tx(&self, _txid: &Txid) -> Result<Option<Transaction>, Error> {
+ Ok(None)
+ }
+ fn broadcast(&self, _tx: &Transaction) -> Result<(), Error> {
+ Ok(())
+ }
+ fn get_height(&self) -> Result<u32, Error> {
+ Ok(42)
+ }
+ fn estimate_fee(&self, _target: usize) -> Result<FeeRate, Error> {
+ Ok(FeeRate::default_min_relay_fee())
+ }
+ }
+
+ #[test]
+ fn test_verify_fail_unsigned_tx() {
+ let prev_tx: Transaction = deserialize(&Vec::<u8>::from_hex("020000000101192dea5e66d444380e106f8e53acb171703f00d43fb6b3ae88ca5644bdb7e1000000006b48304502210098328d026ce138411f957966c1cf7f7597ccbb170f5d5655ee3e9f47b18f6999022017c3526fc9147830e1340e04934476a3d1521af5b4de4e98baf49ec4c072079e01210276f847f77ec8dd66d78affd3c318a0ed26d89dab33fa143333c207402fcec352feffffff023d0ac203000000001976a9144bfbaf6afb76cc5771bc6404810d1cc041a6933988aca4b956050000000017a91494d5543c74a3ee98e0cf8e8caef5dc813a0f34b48768cb0700").unwrap()).unwrap();
+ let signed_tx: Transaction = deserialize(&Vec::<u8>::from_hex("02000000013f7cebd65c27431a90bba7f796914fe8cc2ddfc3f2cbd6f7e5f2fc854534da95000000006b483045022100de1ac3bcdfb0332207c4a91f3832bd2c2915840165f876ab47c5f8996b971c3602201c6c053d750fadde599e6f5c4e1963df0f01fc0d97815e8157e3d59fe09ca30d012103699b464d1d8bc9e47d4fb1cdaa89a1c5783d68363c4dbc4b524ed3d857148617feffffff02836d3c01000000001976a914fc25d6d5c94003bf5b0c7b640a248e2c637fcfb088ac7ada8202000000001976a914fbed3d9b11183209a57999d54d59f67c019e756c88ac6acb0700").unwrap()).unwrap();
+
+ let mut database = MemoryDatabase::new();
+ let blockchain = DummyBlockchain;
+
+ let mut unsigned_tx = signed_tx.clone();
+ for input in &mut unsigned_tx.input {
+ input.script_sig = Default::default();
+ input.witness = Default::default();
+ }
+
+ let result = verify_tx(&signed_tx, &database, &blockchain);
+ assert!(result.is_err(), "Should fail with missing input tx");
+ assert!(
+ matches!(result, Err(VerifyError::MissingInputTx(txid)) if txid == prev_tx.txid()),
+ "Error should be a `MissingInputTx` error"
+ );
+
+ // insert the prev_tx
+ database.set_raw_tx(&prev_tx).unwrap();
+
+ let result = verify_tx(&unsigned_tx, &database, &blockchain);
+ assert!(result.is_err(), "Should fail since the TX is unsigned");
+ assert!(
+ matches!(result, Err(VerifyError::Consensus(_))),
+ "Error should be a `Consensus` error"
+ );
+
+ let result = verify_tx(&signed_tx, &database, &blockchain);
+ assert!(
+ result.is_ok(),
+ "Should work since the TX is correctly signed"
+ );
+ }
+}
projects / bdk / commitdiff