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Merge #584: descriptors: fix analysis of missing signatures post #575

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10acc482e15c0f5832da576baddd10ce44dc85df descriptors: fix the signatures count analysis (Antoine Poinsot)
7a33040b83796b0517a4955ac69f8766577b8442 descriptors: make signed_pubkeys a mapping from fingerprint (Antoine Poinsot)

Pull request description:

  Needs more testing but that should do the trick: we need to take into account the derivation path appended to the xpub in addition to the one from the origin!

ACKs for top commit:
  darosior:
    ACK 10acc482e15c0f5832da576baddd10ce44dc85df -- Edouard ACK'd the child PR at https://github.com/wizardsardine/liana/pull/599#pullrequestreview-1571990532

Tree-SHA512: 912f482c5e10ece4127ffc86620f8ec581d0a209f8e1d407fd9885a7b6d1dfb13e7d5898c75da782282b9d40f69a80ad835e5a7648ceddcfc809445cdf246efb
This commit is contained in:
Antoine Poinsot 2023-08-11 10:24:09 +02:00
commit aab328dd50
No known key found for this signature in database
GPG Key ID: E13FC145CD3F4304
2 changed files with 73 additions and 61 deletions
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106
src/descriptors/analysis.rs
View File

@ -130,13 +130,27 @@ fn csv_check(csv_value: u32) -> Result<u16, LianaPolicyError> {
}
}
// Get the origin of a key in a multipath descriptors.
// Returns None if the given key isn't a multixpub.
fn key_origin(
// Get the fingerprint and the full derivation paths (path from the master fingerprint in the
// origin, with the xpub derivation path appended) for a multipath xpub.
fn key_origins(
key: &descriptor::DescriptorPublicKey,
) -> Option<&(bip32::Fingerprint, bip32::DerivationPath)> {
) -> Option<(bip32::Fingerprint, HashSet<bip32::DerivationPath>)> {
match key {
descriptor::DescriptorPublicKey::MultiXPub(ref xpub) => xpub.origin.as_ref(),
descriptor::DescriptorPublicKey::MultiXPub(ref xpub) => {
xpub.origin.as_ref().map(|(fg, orig_path)| {
let mut der_paths = HashSet::with_capacity(xpub.derivation_paths.paths().len());
for der_path in xpub.derivation_paths.paths() {
der_paths.insert(
orig_path
.into_iter()
.chain(der_path.into_iter())
.copied()
.collect(),
);
}
(*fg, der_paths)
})
}
_ => None,
}
}
@ -241,28 +255,36 @@ impl PathInfo {
}
/// Get the required number of keys for spending through this path, and the set of keys
/// that can be used to provide a signature for this path.
pub fn thresh_origins(&self) -> (usize, HashSet<(bip32::Fingerprint, bip32::DerivationPath)>) {
/// that can be used to provide a signature for this path. The set of keys is represented as a
/// mapping from a master extended key fingerprint, to a set of derivation paths. This is
/// because we are using multipath descriptors. The derivation paths included the xpub's
/// derivation path appended to the origin's derivation path (without the wildcard step).
pub fn thresh_origins(
&self,
) -> (
usize,
HashMap<bip32::Fingerprint, HashSet<bip32::DerivationPath>>,
) {
match self {
PathInfo::Single(key) => {
let mut origins = HashSet::with_capacity(1);
origins.insert(
key_origin(key)
.expect("Must be a multixpub with an origin.")
.clone(),
);
(1, origins)
let mut all_origins = HashMap::with_capacity(1);
let (fg, der_path) = key_origins(key).expect("Must be a multixpub with an origin.");
all_origins.insert(fg, der_path);
(1, all_origins)
}
PathInfo::Multi(k, keys) => {
let mut all_origins: HashMap<_, HashSet<_>> = HashMap::with_capacity(keys.len());
for key in keys {
let (fg, der_paths) =
key_origins(key).expect("Must be a multixpub with an origin.");
if let Some(existing_der_paths) = all_origins.get_mut(&fg) {
existing_der_paths.extend(der_paths)
} else {
all_origins.insert(fg, der_paths);
}
}
(*k, all_origins)
}
PathInfo::Multi(k, keys) => (
*k,
keys.iter()
.map(|key| {
key_origin(key)
.expect("Must be a multixpub with an origin.")
.clone()
})
.collect(),
),
}
}
@ -278,24 +300,28 @@ impl PathInfo {
// For all existing signatures, pick those that are from one of our pubkeys.
for (fg, der_path) in all_pubkeys_signed {
// For all xpubs in the descriptor, we derive at /0/* or /1/*, so the xpub's origin's
// derivation path is the key's one without the last two derivation indexes.
if der_path.len() < 2 {
// All xpubs in the descriptor must be wildcard, and therefore have a derivation with
// at least one step. (In practice there is at least two, for `/<0;1>/*`.)
if der_path.is_empty() {
continue;
}
let parent_der_path: bip32::DerivationPath = der_path[..der_path.len() - 2].into();
let parent_origin = (*fg, parent_der_path);
// Now if the origin of this key without the two final derivation indexes is part of
// the set of our keys, count it as a signature for it. Note it won't mixup keys
// between spending paths, since we can't have duplicate xpubs in the descriptor and
// the (fingerprint, der_path) tuple is a UID for an xpub.
if origins.contains(&parent_origin) {
sigs_count += 1;
if let Some(count) = signed_pubkeys.get_mut(&parent_origin) {
*count += 1;
} else {
signed_pubkeys.insert(parent_origin, 1);
// Now check if this signature is for a public key derived from the fingerprint of one
// of our known master xpubs.
if let Some(parent_der_paths) = origins.get(fg) {
// If it is, make sure it's for one of the xpubs included in the descriptor. Remove
// the wilcard step and check if it's in the set of the derivation paths.
let der_path_wo_wc: bip32::DerivationPath = der_path[..der_path.len() - 1].into();
if parent_der_paths.contains(&der_path_wo_wc) {
// If the origin of the key without the wilcard step is part of our keys, count
// it as a signature. Also record how many times this master extended key
// signed.
sigs_count += 1;
if let Some(count) = signed_pubkeys.get_mut(fg) {
*count += 1;
} else {
signed_pubkeys.insert(*fg, 1);
}
}
}
}
@ -516,7 +542,7 @@ pub struct PathSpendInfo {
pub sigs_count: usize,
/// The keys for which a signature was provided and the number (always >=1) of
/// signatures provided for this key.
pub signed_pubkeys: HashMap<(bip32::Fingerprint, bip32::DerivationPath), usize>,
pub signed_pubkeys: HashMap<bip32::Fingerprint, usize>,
}
/// Information about a partial spend of Liana coins

28
src/descriptors/mod.rs
View File

@ -762,10 +762,7 @@ mod tests {
// A simple descriptor with 1 keys as primary path and 1 recovery key.
let desc = LianaDescriptor::from_str("wsh(or_d(pk([f5acc2fd]tpubD6NzVbkrYhZ4YgUx2ZLNt2rLYAMTdYysCRzKoLu2BeSHKvzqPaBDvf17GeBPnExUVPkuBpx4kniP964e2MxyzzazcXLptxLXModSVCVEV1T/<0;1>/*),and_v(v:pkh([8a64f2a9]tpubD6NzVbkrYhZ4WmzFjvQrp7sDa4ECUxTi9oby8K4FZkd3XCBtEdKwUiQyYJaxiJo5y42gyDWEczrFpozEjeLxMPxjf2WtkfcbpUdfvNnozWF/<0;1>/*),older(10))))#d72le4dr").unwrap();
let desc_info = desc.policy();
let prim_key_origin = (
bip32::Fingerprint::from_str("f5acc2fd").unwrap(),
Vec::new().into(),
);
let prim_key_fg = bip32::Fingerprint::from_str("f5acc2fd").unwrap();
let recov_key_origin: (_, bip32::DerivationPath) = (
bip32::Fingerprint::from_str("8a64f2a9").unwrap(),
Vec::new().into(),
@ -806,12 +803,10 @@ mod tests {
assert_eq!(signed_single_psbt.inputs[0].partial_sigs.len(), 1);
assert_eq!(info.primary_path.threshold, 1);
assert_eq!(info.primary_path.sigs_count, 1);
dbg!(&info.primary_path.signed_pubkeys);
assert!(
info.primary_path.signed_pubkeys.len() == 1
&& info
.primary_path
.signed_pubkeys
.contains_key(&prim_key_origin)
&& info.primary_path.signed_pubkeys.contains_key(&prim_key_fg)
);
assert!(info.recovery_paths.is_empty());
@ -852,7 +847,7 @@ mod tests {
assert_eq!(recov_info.sigs_count, 1);
assert!(
recov_info.signed_pubkeys.len() == 1
&& recov_info.signed_pubkeys.contains_key(&recov_key_origin)
&& recov_info.signed_pubkeys.contains_key(&recov_key_origin.0)
);
// A PSBT with multiple inputs, all signed for the primary path.
@ -866,10 +861,7 @@ mod tests {
assert_eq!(info.primary_path.sigs_count, 1);
assert!(
info.primary_path.signed_pubkeys.len() == 1
&& info
.primary_path
.signed_pubkeys
.contains_key(&prim_key_origin)
&& info.primary_path.signed_pubkeys.contains_key(&prim_key_fg)
);
assert!(info.recovery_paths.is_empty());
@ -887,10 +879,7 @@ mod tests {
assert_eq!(info.primary_path.sigs_count, 1);
assert!(
info.primary_path.signed_pubkeys.len() == 1
&& info
.primary_path
.signed_pubkeys
.contains_key(&prim_key_origin)
&& info.primary_path.signed_pubkeys.contains_key(&prim_key_fg)
);
let recov_info = info.recovery_paths.get(&timelock).unwrap();
assert_eq!(recov_info.threshold, 1);
@ -927,10 +916,7 @@ mod tests {
assert_eq!(info.primary_path.sigs_count, 1);
assert!(
info.primary_path.signed_pubkeys.len() == 1
&& info
.primary_path
.signed_pubkeys
.contains_key(&prim_key_origin)
&& info.primary_path.signed_pubkeys.contains_key(&prim_key_fg)
);
assert!(info.recovery_paths.is_empty());