diff --git a/Cargo-minimal.lock b/Cargo-minimal.lock index 598fe6061..24cb2fbc6 100644 --- a/Cargo-minimal.lock +++ b/Cargo-minimal.lock @@ -53,9 +53,9 @@ checksum = "d965446196e3b7decd44aa7ee49e31d630118f90ef12f97900f262eb915c951d" [[package]] name = "bitcoin" -version = "0.32.0" +version = "0.32.6" source = "registry+https://github.com/rust-lang/crates.io-index" -checksum = "7170e7750a20974246f17ece04311b4205a6155f1db564c5b224af817663c3ea" +checksum = "ad8929a18b8e33ea6b3c09297b687baaa71fb1b97353243a3f1029fad5c59c5b" dependencies = [ "base58ck", "base64 0.21.7", diff --git a/Cargo-recent.lock b/Cargo-recent.lock index 116fe1150..08eff6314 100644 --- a/Cargo-recent.lock +++ b/Cargo-recent.lock @@ -53,9 +53,9 @@ checksum = "d965446196e3b7decd44aa7ee49e31d630118f90ef12f97900f262eb915c951d" [[package]] name = "bitcoin" -version = "0.32.0" +version = "0.32.6" source = "registry+https://github.com/rust-lang/crates.io-index" -checksum = "7170e7750a20974246f17ece04311b4205a6155f1db564c5b224af817663c3ea" +checksum = "ad8929a18b8e33ea6b3c09297b687baaa71fb1b97353243a3f1029fad5c59c5b" dependencies = [ "base58ck", "base64 0.21.7", diff --git a/Cargo.toml b/Cargo.toml index 8ea9d993b..e7c96bcb5 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -23,7 +23,7 @@ base64 = ["bitcoin/base64"] [dependencies] bech32 = { version = "0.11.0", default-features = false } -bitcoin = { version = "0.32.0", default-features = false } +bitcoin = { version = "0.32.6", default-features = false } # Do NOT use this as a feature! Use the `serde` feature instead. actual-serde = { package = "serde", version = "1.0.103", optional = true } diff --git a/src/descriptor/key_map.rs b/src/descriptor/key_map.rs new file mode 100644 index 000000000..00c797ee1 --- /dev/null +++ b/src/descriptor/key_map.rs @@ -0,0 +1,361 @@ +use bitcoin::psbt::{GetKey, GetKeyError, KeyRequest}; +use bitcoin::secp256k1::{Secp256k1, Signing}; +use bitcoin::PrivateKey; + +use crate::descriptor::{DescriptorSecretKey, KeyMap}; +use crate::BTreeMap; + +/// A wrapper around KeyMap that implements GetKey for PSBT signing. +#[derive(Debug, Clone, Eq, PartialEq)] +pub struct KeyMapWrapper { + map: KeyMap, +} + +impl From for KeyMapWrapper { + fn from(map: KeyMap) -> Self { KeyMapWrapper { map } } +} + +impl GetKey for KeyMapWrapper { + type Error = GetKeyError; + + fn get_key( + &self, + key_request: KeyRequest, + secp: &Secp256k1, + ) -> Result, Self::Error> { + Ok(self + .map + .iter() + .find_map(|(_desc_pk, desc_sk)| -> Option { + match desc_sk.get_key(key_request.clone(), secp) { + Ok(Some(pk)) => Some(pk), + // When looking up keys in a map, we eat errors on individual keys, on + // the assumption that some other key in the map might not error. + Ok(None) | Err(_) => None, + } + })) + } +} + +impl GetKey for DescriptorSecretKey { + type Error = GetKeyError; + + fn get_key( + &self, + key_request: KeyRequest, + secp: &Secp256k1, + ) -> Result, Self::Error> { + match (self, key_request) { + (DescriptorSecretKey::Single(single_priv), key_request) => { + let sk = single_priv.key; + let pk = sk.public_key(secp); + let pubkey_map = BTreeMap::from([(pk, sk)]); + pubkey_map.get_key(key_request, secp) + } + (DescriptorSecretKey::XPrv(descriptor_xkey), KeyRequest::Pubkey(public_key)) => { + let xpriv = descriptor_xkey + .xkey + .derive_priv(secp, &descriptor_xkey.derivation_path) + .map_err(GetKeyError::Bip32)?; + let pk = xpriv.private_key.public_key(secp); + + if public_key.inner.eq(&pk) { + Ok(Some(xpriv.to_priv())) + } else { + Ok(None) + } + } + ( + DescriptorSecretKey::XPrv(descriptor_xkey), + ref key_request @ KeyRequest::Bip32(ref key_source), + ) => { + if let Some(key) = descriptor_xkey.xkey.get_key(key_request.clone(), secp)? { + return Ok(Some(key)); + } + + if descriptor_xkey.matches(key_source, secp).is_some() { + let (_, derivation_path) = key_source; + return Ok(Some( + descriptor_xkey + .xkey + .derive_priv(secp, &derivation_path) + .map_err(GetKeyError::Bip32)? + .to_priv(), + )); + } + + Ok(None) + } + (DescriptorSecretKey::XPrv(_), KeyRequest::XOnlyPubkey(_)) => { + Err(GetKeyError::NotSupported) + } + ( + desc_multi_sk @ DescriptorSecretKey::MultiXPrv(_descriptor_multi_xkey), + key_request, + ) => { + for desc_sk in &desc_multi_sk.clone().into_single_keys() { + // If any key is an error, then all of them will, so here we propagate errors with ?. + if let Some(pk) = desc_sk.get_key(key_request.clone(), secp)? { + return Ok(Some(pk)); + } + } + Ok(None) + } + _ => Ok(None), + } + } +} + +#[cfg(test)] +mod tests { + use core::str::FromStr; + + use bitcoin::bip32::{ChildNumber, DerivationPath, IntoDerivationPath, Xpriv}; + + use super::*; + use crate::Descriptor; + + #[test] + fn get_key_single_key() { + let secp = Secp256k1::new(); + + let descriptor_sk_s = + "[90b6a706/44'/0'/0'/0/0]cMk8gWmj1KpjdYnAWwsEDekodMYhbyYBhG8gMtCCxucJ98JzcNij"; + + let single = match descriptor_sk_s.parse::().unwrap() { + DescriptorSecretKey::Single(single) => single, + _ => panic!("unexpected DescriptorSecretKey variant"), + }; + + let want_sk = single.key; + let descriptor_s = format!("wpkh({})", descriptor_sk_s); + let (_, keymap) = Descriptor::parse_descriptor(&secp, &descriptor_s).unwrap(); + let keymap_wrapper = KeyMapWrapper::from(keymap); + + let pk = want_sk.public_key(&secp); + let request = KeyRequest::Pubkey(pk); + let got_sk = keymap_wrapper + .get_key(request, &secp) + .expect("get_key call errored") + .expect("failed to find the key"); + assert_eq!(got_sk, want_sk) + } + + #[test] + fn get_key_xpriv_single_key_xpriv() { + let secp = Secp256k1::new(); + + let s = "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi"; + + let xpriv = s.parse::().unwrap(); + let xpriv_fingerprint = xpriv.fingerprint(&secp); + + // Sanity check. + { + let descriptor_sk_s = format!("[{}]{}", xpriv_fingerprint, xpriv); + let descriptor_sk = descriptor_sk_s.parse::().unwrap(); + let got = match descriptor_sk { + DescriptorSecretKey::XPrv(x) => x.xkey, + _ => panic!("unexpected DescriptorSecretKey variant"), + }; + assert_eq!(got, xpriv); + } + + let want_sk = xpriv.to_priv(); + let descriptor_s = format!("wpkh([{}]{})", xpriv_fingerprint, xpriv); + let (_, keymap) = Descriptor::parse_descriptor(&secp, &descriptor_s).unwrap(); + let keymap_wrapper = KeyMapWrapper::from(keymap); + + let pk = want_sk.public_key(&secp); + let request = KeyRequest::Pubkey(pk); + let got_sk = keymap_wrapper + .get_key(request, &secp) + .expect("get_key call errored") + .expect("failed to find the key"); + assert_eq!(got_sk, want_sk) + } + + #[test] + fn get_key_xpriv_child_depth_one() { + let secp = Secp256k1::new(); + + let s = "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi"; + let master = s.parse::().unwrap(); + let master_fingerprint = master.fingerprint(&secp); + + let child_number = ChildNumber::from_hardened_idx(44).unwrap(); + let child = master.derive_priv(&secp, &[child_number]).unwrap(); + + // Sanity check. + { + let descriptor_sk_s = format!("[{}/44']{}", master_fingerprint, child); + let descriptor_sk = descriptor_sk_s.parse::().unwrap(); + let got = match descriptor_sk { + DescriptorSecretKey::XPrv(ref x) => x.xkey, + _ => panic!("unexpected DescriptorSecretKey variant"), + }; + assert_eq!(got, child); + } + + let want_sk = child.to_priv(); + let descriptor_s = format!("wpkh({}/44')", s); + let (_, keymap) = Descriptor::parse_descriptor(&secp, &descriptor_s).unwrap(); + let keymap_wrapper = KeyMapWrapper::from(keymap); + + let pk = want_sk.public_key(&secp); + let request = KeyRequest::Pubkey(pk); + let got_sk = keymap_wrapper + .get_key(request, &secp) + .expect("get_key call errored") + .expect("failed to find the key"); + assert_eq!(got_sk, want_sk) + } + + #[test] + fn get_key_xpriv_with_path() { + let secp = Secp256k1::new(); + + let s = "xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi"; + let master = s.parse::().unwrap(); + let master_fingerprint = master.fingerprint(&secp); + + let first_external_child = "44'/0'/0'/0/0"; + let derivation_path = first_external_child.into_derivation_path().unwrap(); + + let child = master.derive_priv(&secp, &derivation_path).unwrap(); + + // Sanity check. + { + let descriptor_sk_s = + format!("[{}/{}]{}", master_fingerprint, first_external_child, child); + let descriptor_sk = descriptor_sk_s.parse::().unwrap(); + let got = match descriptor_sk { + DescriptorSecretKey::XPrv(ref x) => x.xkey, + _ => panic!("unexpected DescriptorSecretKey variant"), + }; + assert_eq!(got, child); + } + + let want_sk = child.to_priv(); + let descriptor_s = format!("wpkh({}/44'/0'/0'/0/*)", s); + let (_, keymap) = Descriptor::parse_descriptor(&secp, &descriptor_s).unwrap(); + let keymap_wrapper = KeyMapWrapper::from(keymap); + + let key_source = (master_fingerprint, derivation_path); + let request = KeyRequest::Bip32(key_source); + let got_sk = keymap_wrapper + .get_key(request, &secp) + .expect("get_key call errored") + .expect("failed to find the key"); + + assert_eq!(got_sk, want_sk) + } + + #[test] + fn get_key_xpriv_with_key_origin() { + let secp = Secp256k1::new(); + + let descriptor_str = "wpkh([d34db33f/84h/1h/0h]tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)"; + let (_descriptor_pk, keymap) = Descriptor::parse_descriptor(&secp, descriptor_str).unwrap(); + let keymap_wrapper = KeyMapWrapper::from(keymap); + + let descriptor_sk = DescriptorSecretKey::from_str("[d34db33f/84h/1h/0h]tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*").unwrap(); + let xpriv = match descriptor_sk { + DescriptorSecretKey::XPrv(descriptor_xkey) => descriptor_xkey, + _ => unreachable!(), + }; + + let path = DerivationPath::from_str("84'/1'/0'/0").unwrap(); + let expected_pk = xpriv.xkey.derive_priv(&secp, &path).unwrap().to_priv(); + + let (fp, _) = xpriv.origin.unwrap(); + let key_request = KeyRequest::Bip32((fp, path)); + + let pk = keymap_wrapper + .get_key(key_request, &secp) + .expect("get_key should not fail") + .expect("get_key should return a `PrivateKey`"); + + assert_eq!(pk, expected_pk); + } + + #[test] + fn get_key_keymap_no_match() { + let secp = Secp256k1::new(); + + // Create a keymap with one key + let descriptor_s = "wpkh(cMk8gWmj1KpjdYnAWwsEDekodMYhbyYBhG8gMtCCxucJ98JzcNij)"; + let (_, keymap) = Descriptor::parse_descriptor(&secp, descriptor_s).unwrap(); + let keymap_wrapper = KeyMapWrapper::from(keymap); + + // Request a different public key that doesn't exist in the keymap + let different_sk = + PrivateKey::from_str("cNJFgo1driFnPcBdBX8BrJrpxchBWXwXCvNH5SoSkdcF6JXXwHMm").unwrap(); + let different_pk = different_sk.public_key(&secp); + let request = KeyRequest::Pubkey(different_pk); + + let result = keymap_wrapper.get_key(request, &secp).unwrap(); + assert!(result.is_none(), "Should return None when no matching key is found"); + } + + #[test] + fn get_key_descriptor_secret_key_xonly_not_supported() { + let secp = Secp256k1::new(); + + let descriptor_sk = DescriptorSecretKey::from_str("xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi").unwrap(); + + // Create an x-only public key request + let sk = + PrivateKey::from_str("cMk8gWmj1KpjdYnAWwsEDekodMYhbyYBhG8gMtCCxucJ98JzcNij").unwrap(); + let xonly_pk = sk.public_key(&secp).inner.x_only_public_key().0; + let request = KeyRequest::XOnlyPubkey(xonly_pk); + + let result = descriptor_sk.get_key(request.clone(), &secp); + assert!(matches!(result, Err(GetKeyError::NotSupported))); + + // Also test with KeyMap + let descriptor_s = "wpkh(xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi)"; + let (_, keymap) = Descriptor::parse_descriptor(&secp, descriptor_s).unwrap(); + let keymap_wrapper = KeyMapWrapper::from(keymap); + + // While requesting an x-only key from an individual xpriv, that's an error. + // But from a keymap, which might have both x-only keys and regular xprivs, + // we treat errors as "key not found". + let result = keymap_wrapper.get_key(request, &secp); + assert!(matches!(result, Ok(None))); + } + + #[test] + fn get_key_descriptor_secret_key_xonly_multipath() { + let secp = Secp256k1::new(); + + let descriptor_sk = DescriptorSecretKey::from_str("[d34db33f/84h/0h/0h]tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/<0;1>").unwrap(); + + // Request with a different fingerprint + let different_fingerprint = bitcoin::bip32::Fingerprint::from([0x12, 0x34, 0x56, 0x78]); + let path = DerivationPath::from_str("84'/1'/0'/0").unwrap(); + let request = KeyRequest::Bip32((different_fingerprint, path)); + + let result = descriptor_sk.get_key(request.clone(), &secp).unwrap(); + assert!(result.is_none(), "Should return None when fingerprint doesn't match"); + + // Create an x-only public key request -- now we get "not supported". + let sk = + PrivateKey::from_str("cMk8gWmj1KpjdYnAWwsEDekodMYhbyYBhG8gMtCCxucJ98JzcNij").unwrap(); + let xonly_pk = sk.public_key(&secp).inner.x_only_public_key().0; + let request_x = KeyRequest::XOnlyPubkey(xonly_pk); + + let result = descriptor_sk.get_key(request_x.clone(), &secp); + assert!(matches!(result, Err(GetKeyError::NotSupported))); + + // Also test with KeyMap; as in the previous test, the error turns to None. + let descriptor_s = "wpkh([d34db33f/84h/1h/0h]tprv8ZgxMBicQKsPd3EupYiPRhaMooHKUHJxNsTfYuScep13go8QFfHdtkG9nRkFGb7busX4isf6X9dURGCoKgitaApQ6MupRhZMcELAxTBRJgS/*)"; + let (_, keymap) = Descriptor::parse_descriptor(&secp, descriptor_s).unwrap(); + let keymap_wrapper = KeyMapWrapper::from(keymap); + + let result = keymap_wrapper.get_key(request, &secp).unwrap(); + assert!(result.is_none(), "Should return None when fingerprint doesn't match"); + let result = keymap_wrapper.get_key(request_x, &secp).unwrap(); + assert!(result.is_none(), "Should return None even on error"); + } +} diff --git a/src/descriptor/mod.rs b/src/descriptor/mod.rs index 468fd80f2..9feb36ea8 100644 --- a/src/descriptor/mod.rs +++ b/src/descriptor/mod.rs @@ -46,12 +46,14 @@ pub use self::tr::{TapTree, Tr}; pub mod checksum; mod key; +mod key_map; pub use self::key::{ ConversionError, DefiniteDescriptorKey, DerivPaths, DescriptorKeyParseError, DescriptorMultiXKey, DescriptorPublicKey, DescriptorSecretKey, DescriptorXKey, InnerXKey, SinglePriv, SinglePub, SinglePubKey, Wildcard, }; +pub use self::key_map::KeyMapWrapper; /// Alias type for a map of public key to secret key ///