1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 use crate::ln::channel::{ANCHOR_OUTPUT_VALUE_SATOSHI, MIN_CHAN_DUST_LIMIT_SATOSHIS};
11 use crate::ln::chan_utils::{HTLCOutputInCommitment, ChannelPublicKeys, HolderCommitmentTransaction, CommitmentTransaction, ChannelTransactionParameters, TrustedCommitmentTransaction, ClosingTransaction};
12 use crate::ln::channel_keys::{HtlcKey};
14 use crate::ln::types::PaymentPreimage;
15 use crate::sign::{InMemorySigner, ChannelSigner};
16 use crate::sign::ecdsa::EcdsaChannelSigner;
18 #[allow(unused_imports)]
19 use crate::prelude::*;
22 use crate::sync::{Mutex, Arc};
23 #[cfg(test)] use crate::sync::MutexGuard;
25 use bitcoin::blockdata::transaction::Transaction;
26 use bitcoin::hashes::Hash;
28 use bitcoin::sighash::EcdsaSighashType;
30 use bitcoin::secp256k1;
32 use bitcoin::secp256k1::All;
33 use bitcoin::secp256k1::{SecretKey, PublicKey};
34 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature};
36 use musig2::types::{PartialSignature, PublicNonce, SecretNonce};
37 use crate::sign::HTLCDescriptor;
38 use crate::util::ser::{Writeable, Writer};
40 use crate::ln::features::ChannelTypeFeatures;
42 use crate::ln::msgs::PartialSignatureWithNonce;
44 use crate::sign::taproot::TaprootChannelSigner;
46 /// Initial value for revoked commitment downward counter
47 pub const INITIAL_REVOKED_COMMITMENT_NUMBER: u64 = 1 << 48;
49 /// An implementation of Sign that enforces some policy checks. The current checks
50 /// are an incomplete set. They include:
52 /// - When signing, the holder transaction has not been revoked
53 /// - When revoking, the holder transaction has not been signed
54 /// - The holder commitment number is monotonic and without gaps
55 /// - The revoked holder commitment number is monotonic and without gaps
56 /// - There is at least one unrevoked holder transaction at all times
57 /// - The counterparty commitment number is monotonic and without gaps
58 /// - The pre-derived keys and pre-built transaction in CommitmentTransaction were correctly built
60 /// Eventually we will probably want to expose a variant of this which would essentially
61 /// be what you'd want to run on a hardware wallet.
63 /// Note that counterparty signatures on the holder transaction are not checked, but it should
64 /// be in a complete implementation.
66 /// Note that before we do so we should ensure its serialization format has backwards- and
67 /// forwards-compatibility prefix/suffixes!
69 pub struct TestChannelSigner {
70 pub inner: InMemorySigner,
71 /// Channel state used for policy enforcement
72 pub state: Arc<Mutex<EnforcementState>>,
73 pub disable_revocation_policy_check: bool,
74 /// When `true` (the default), the signer will respond immediately with signatures. When `false`,
75 /// the signer will return an error indicating that it is unavailable.
76 pub available: Arc<Mutex<bool>>,
77 /// Set of signer operations that are disabled. If an operation is disabled,
78 /// the signer will return `Err` when the corresponding method is called.
79 pub disabled_signer_ops: Arc<Mutex<HashSet<SignerOp>>>,
82 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
84 GetPerCommitmentPoint,
85 ReleaseCommitmentSecret,
86 ValidateHolderCommitment,
87 SignCounterpartyCommitment,
88 ValidateCounterpartyRevocation,
90 SignJusticeRevokedOutput,
91 SignJusticeRevokedHtlc,
92 SignHolderHtlcTransaction,
93 SignCounterpartyHtlcTransaction,
94 SignClosingTransaction,
95 SignHolderAnchorInput,
96 SignChannelAnnouncementWithFundingKey,
99 impl fmt::Display for SignerOp {
100 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
102 SignerOp::GetPerCommitmentPoint => write!(f, "get_per_commitment_point"),
103 SignerOp::ReleaseCommitmentSecret => write!(f, "release_commitment_secret"),
104 SignerOp::ValidateHolderCommitment => write!(f, "validate_holder_commitment"),
105 SignerOp::SignCounterpartyCommitment => write!(f, "sign_counterparty_commitment"),
106 SignerOp::ValidateCounterpartyRevocation => write!(f, "validate_counterparty_revocation"),
107 SignerOp::SignHolderCommitment => write!(f, "sign_holder_commitment"),
108 SignerOp::SignJusticeRevokedOutput => write!(f, "sign_justice_revoked_output"),
109 SignerOp::SignJusticeRevokedHtlc => write!(f, "sign_justice_revoked_htlc"),
110 SignerOp::SignHolderHtlcTransaction => write!(f, "sign_holder_htlc_transaction"),
111 SignerOp::SignCounterpartyHtlcTransaction => write!(f, "sign_counterparty_htlc_transaction"),
112 SignerOp::SignClosingTransaction => write!(f, "sign_closing_transaction"),
113 SignerOp::SignHolderAnchorInput => write!(f, "sign_holder_anchor_input"),
114 SignerOp::SignChannelAnnouncementWithFundingKey => write!(f, "sign_channel_announcement_with_funding_key"),
119 impl PartialEq for TestChannelSigner {
120 fn eq(&self, o: &Self) -> bool {
121 Arc::ptr_eq(&self.state, &o.state)
125 impl TestChannelSigner {
126 /// Construct an TestChannelSigner
127 pub fn new(inner: InMemorySigner) -> Self {
128 let state = Arc::new(Mutex::new(EnforcementState::new()));
132 disable_revocation_policy_check: false,
133 available: Arc::new(Mutex::new(true)),
134 disabled_signer_ops: Arc::new(Mutex::new(new_hash_set())),
138 /// Construct an TestChannelSigner with externally managed storage
140 /// Since there are multiple copies of this struct for each channel, some coordination is needed
141 /// so that all copies are aware of enforcement state. A pointer to this state is provided
142 /// here, usually by an implementation of KeysInterface.
143 pub fn new_with_revoked(inner: InMemorySigner, state: Arc<Mutex<EnforcementState>>, disable_revocation_policy_check: bool) -> Self {
147 disable_revocation_policy_check,
148 available: Arc::new(Mutex::new(true)),
149 disabled_signer_ops: Arc::new(Mutex::new(new_hash_set())),
153 pub fn channel_type_features(&self) -> &ChannelTypeFeatures { self.inner.channel_type_features().unwrap() }
156 pub fn get_enforcement_state(&self) -> MutexGuard<EnforcementState> {
157 self.state.lock().unwrap()
160 /// Marks the signer's availability.
162 /// When `true`, methods are forwarded to the underlying signer as normal. When `false`, some
163 /// methods will return `Err` indicating that the signer is unavailable. Intended to be used for
164 /// testing asynchronous signing.
165 pub fn set_available(&self, available: bool) {
166 *self.available.lock().unwrap() = available;
169 pub fn enable_op(&mut self, signer_op: SignerOp) {
170 self.disabled_signer_ops.lock().unwrap().remove(&signer_op);
173 pub fn disable_op(&mut self, signer_op: SignerOp) {
174 self.disabled_signer_ops.lock().unwrap().insert(signer_op);
177 fn is_signer_available(&self, signer_op: SignerOp) -> bool {
178 !self.disabled_signer_ops.lock().unwrap().contains(&signer_op)
182 impl ChannelSigner for TestChannelSigner {
183 fn get_per_commitment_point(&self, idx: u64, secp_ctx: &Secp256k1<secp256k1::All>) -> PublicKey {
184 self.inner.get_per_commitment_point(idx, secp_ctx)
187 fn release_commitment_secret(&self, idx: u64) -> [u8; 32] {
189 let mut state = self.state.lock().unwrap();
190 assert!(idx == state.last_holder_revoked_commitment || idx == state.last_holder_revoked_commitment - 1, "can only revoke the current or next unrevoked commitment - trying {}, last revoked {}", idx, state.last_holder_revoked_commitment);
191 assert!(idx > state.last_holder_commitment, "cannot revoke the last holder commitment - attempted to revoke {} last commitment {}", idx, state.last_holder_commitment);
192 state.last_holder_revoked_commitment = idx;
194 self.inner.release_commitment_secret(idx)
197 fn validate_holder_commitment(&self, holder_tx: &HolderCommitmentTransaction, _outbound_htlc_preimages: Vec<PaymentPreimage>) -> Result<(), ()> {
198 let mut state = self.state.lock().unwrap();
199 let idx = holder_tx.commitment_number();
200 assert!(idx == state.last_holder_commitment || idx == state.last_holder_commitment - 1, "expecting to validate the current or next holder commitment - trying {}, current {}", idx, state.last_holder_commitment);
201 state.last_holder_commitment = idx;
205 fn validate_counterparty_revocation(&self, idx: u64, _secret: &SecretKey) -> Result<(), ()> {
206 if !*self.available.lock().unwrap() {
209 let mut state = self.state.lock().unwrap();
210 assert!(idx == state.last_counterparty_revoked_commitment || idx == state.last_counterparty_revoked_commitment - 1, "expecting to validate the current or next counterparty revocation - trying {}, current {}", idx, state.last_counterparty_revoked_commitment);
211 state.last_counterparty_revoked_commitment = idx;
215 fn pubkeys(&self) -> &ChannelPublicKeys { self.inner.pubkeys() }
217 fn channel_keys_id(&self) -> [u8; 32] { self.inner.channel_keys_id() }
219 fn provide_channel_parameters(&mut self, channel_parameters: &ChannelTransactionParameters) {
220 self.inner.provide_channel_parameters(channel_parameters)
224 impl EcdsaChannelSigner for TestChannelSigner {
225 fn sign_counterparty_commitment(&self, commitment_tx: &CommitmentTransaction, inbound_htlc_preimages: Vec<PaymentPreimage>, outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<(Signature, Vec<Signature>), ()> {
226 self.verify_counterparty_commitment_tx(commitment_tx, secp_ctx);
229 if !*self.available.lock().unwrap() {
232 let mut state = self.state.lock().unwrap();
233 let actual_commitment_number = commitment_tx.commitment_number();
234 let last_commitment_number = state.last_counterparty_commitment;
235 // These commitment numbers are backwards counting. We expect either the same as the previously encountered,
237 assert!(last_commitment_number == actual_commitment_number || last_commitment_number - 1 == actual_commitment_number, "{} doesn't come after {}", actual_commitment_number, last_commitment_number);
238 // Ensure that the counterparty doesn't get more than two broadcastable commitments -
239 // the last and the one we are trying to sign
240 assert!(actual_commitment_number >= state.last_counterparty_revoked_commitment - 2, "cannot sign a commitment if second to last wasn't revoked - signing {} revoked {}", actual_commitment_number, state.last_counterparty_revoked_commitment);
241 state.last_counterparty_commitment = cmp::min(last_commitment_number, actual_commitment_number)
244 Ok(self.inner.sign_counterparty_commitment(commitment_tx, inbound_htlc_preimages, outbound_htlc_preimages, secp_ctx).unwrap())
247 fn sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
248 if !*self.available.lock().unwrap() {
251 let trusted_tx = self.verify_holder_commitment_tx(commitment_tx, secp_ctx);
252 let state = self.state.lock().unwrap();
253 let commitment_number = trusted_tx.commitment_number();
254 if state.last_holder_revoked_commitment - 1 != commitment_number && state.last_holder_revoked_commitment - 2 != commitment_number {
255 if !self.disable_revocation_policy_check {
256 panic!("can only sign the next two unrevoked commitment numbers, revoked={} vs requested={} for {}",
257 state.last_holder_revoked_commitment, commitment_number, self.inner.commitment_seed[0])
260 Ok(self.inner.sign_holder_commitment(commitment_tx, secp_ctx).unwrap())
263 #[cfg(any(test,feature = "unsafe_revoked_tx_signing"))]
264 fn unsafe_sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
265 Ok(self.inner.unsafe_sign_holder_commitment(commitment_tx, secp_ctx).unwrap())
268 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
269 if !*self.available.lock().unwrap() {
272 Ok(EcdsaChannelSigner::sign_justice_revoked_output(&self.inner, justice_tx, input, amount, per_commitment_key, secp_ctx).unwrap())
275 fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
276 if !*self.available.lock().unwrap() {
279 Ok(EcdsaChannelSigner::sign_justice_revoked_htlc(&self.inner, justice_tx, input, amount, per_commitment_key, htlc, secp_ctx).unwrap())
282 fn sign_holder_htlc_transaction(
283 &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor,
284 secp_ctx: &Secp256k1<secp256k1::All>
285 ) -> Result<Signature, ()> {
286 if !*self.available.lock().unwrap() {
289 let state = self.state.lock().unwrap();
290 if state.last_holder_revoked_commitment - 1 != htlc_descriptor.per_commitment_number &&
291 state.last_holder_revoked_commitment - 2 != htlc_descriptor.per_commitment_number
293 if !self.disable_revocation_policy_check {
294 panic!("can only sign the next two unrevoked commitment numbers, revoked={} vs requested={} for {}",
295 state.last_holder_revoked_commitment, htlc_descriptor.per_commitment_number, self.inner.commitment_seed[0])
298 assert_eq!(htlc_tx.input[input], htlc_descriptor.unsigned_tx_input());
299 assert_eq!(htlc_tx.output[input], htlc_descriptor.tx_output(secp_ctx));
301 let witness_script = htlc_descriptor.witness_script(secp_ctx);
302 let sighash_type = if self.channel_type_features().supports_anchors_zero_fee_htlc_tx() {
303 EcdsaSighashType::SinglePlusAnyoneCanPay
305 EcdsaSighashType::All
307 let sighash = &sighash::SighashCache::new(&*htlc_tx).p2wsh_signature_hash(
308 input, &witness_script, htlc_descriptor.htlc.to_bitcoin_amount(), sighash_type
310 let countersignatory_htlc_key = HtlcKey::from_basepoint(
311 &secp_ctx, &self.inner.counterparty_pubkeys().unwrap().htlc_basepoint, &htlc_descriptor.per_commitment_point,
314 secp_ctx.verify_ecdsa(
315 &hash_to_message!(sighash.as_byte_array()), &htlc_descriptor.counterparty_sig, &countersignatory_htlc_key.to_public_key()
318 Ok(EcdsaChannelSigner::sign_holder_htlc_transaction(&self.inner, htlc_tx, input, htlc_descriptor, secp_ctx).unwrap())
321 fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
322 if !*self.available.lock().unwrap() {
325 Ok(EcdsaChannelSigner::sign_counterparty_htlc_transaction(&self.inner, htlc_tx, input, amount, per_commitment_point, htlc, secp_ctx).unwrap())
328 fn sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<secp256k1::All>) -> Result<Signature, ()> {
329 closing_tx.verify(self.inner.funding_outpoint().unwrap().into_bitcoin_outpoint())
330 .expect("derived different closing transaction");
331 Ok(self.inner.sign_closing_transaction(closing_tx, secp_ctx).unwrap())
334 fn sign_holder_anchor_input(
335 &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<secp256k1::All>,
336 ) -> Result<Signature, ()> {
337 debug_assert!(MIN_CHAN_DUST_LIMIT_SATOSHIS > ANCHOR_OUTPUT_VALUE_SATOSHI);
338 // As long as our minimum dust limit is enforced and is greater than our anchor output
339 // value, an anchor output can only have an index within [0, 1].
340 assert!(anchor_tx.input[input].previous_output.vout == 0 || anchor_tx.input[input].previous_output.vout == 1);
341 if !*self.available.lock().unwrap() {
344 EcdsaChannelSigner::sign_holder_anchor_input(&self.inner, anchor_tx, input, secp_ctx)
347 fn sign_channel_announcement_with_funding_key(
348 &self, msg: &msgs::UnsignedChannelAnnouncement, secp_ctx: &Secp256k1<secp256k1::All>
349 ) -> Result<Signature, ()> {
350 self.inner.sign_channel_announcement_with_funding_key(msg, secp_ctx)
355 impl TaprootChannelSigner for TestChannelSigner {
356 fn generate_local_nonce_pair(&self, commitment_number: u64, secp_ctx: &Secp256k1<All>) -> PublicNonce {
360 fn partially_sign_counterparty_commitment(&self, counterparty_nonce: PublicNonce, commitment_tx: &CommitmentTransaction, inbound_htlc_preimages: Vec<PaymentPreimage>, outbound_htlc_preimages: Vec<PaymentPreimage>, secp_ctx: &Secp256k1<All>) -> Result<(PartialSignatureWithNonce, Vec<secp256k1::schnorr::Signature>), ()> {
364 fn finalize_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, counterparty_partial_signature: PartialSignatureWithNonce, secp_ctx: &Secp256k1<All>) -> Result<PartialSignature, ()> {
368 fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1<All>) -> Result<secp256k1::schnorr::Signature, ()> {
372 fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>) -> Result<secp256k1::schnorr::Signature, ()> {
376 fn sign_holder_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor, secp_ctx: &Secp256k1<All>) -> Result<secp256k1::schnorr::Signature, ()> {
380 fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1<All>) -> Result<secp256k1::schnorr::Signature, ()> {
384 fn partially_sign_closing_transaction(&self, closing_tx: &ClosingTransaction, secp_ctx: &Secp256k1<All>) -> Result<PartialSignature, ()> {
388 fn sign_holder_anchor_input(&self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1<All>) -> Result<secp256k1::schnorr::Signature, ()> {
393 impl Writeable for TestChannelSigner {
394 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error> {
395 // TestChannelSigner has two fields - `inner` ([`InMemorySigner`]) and `state`
396 // ([`EnforcementState`]). `inner` is serialized here and deserialized by
397 // [`SignerProvider::read_chan_signer`]. `state` is managed by [`SignerProvider`]
398 // and will be serialized as needed by the implementation of that trait.
399 self.inner.write(writer)?;
404 impl TestChannelSigner {
405 fn verify_counterparty_commitment_tx<'a, T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &'a CommitmentTransaction, secp_ctx: &Secp256k1<T>) -> TrustedCommitmentTransaction<'a> {
406 commitment_tx.verify(
407 &self.inner.get_channel_parameters().unwrap().as_counterparty_broadcastable(),
408 self.inner.counterparty_pubkeys().unwrap(), self.inner.pubkeys(), secp_ctx
409 ).expect("derived different per-tx keys or built transaction")
412 fn verify_holder_commitment_tx<'a, T: secp256k1::Signing + secp256k1::Verification>(&self, commitment_tx: &'a CommitmentTransaction, secp_ctx: &Secp256k1<T>) -> TrustedCommitmentTransaction<'a> {
413 commitment_tx.verify(
414 &self.inner.get_channel_parameters().unwrap().as_holder_broadcastable(),
415 self.inner.pubkeys(), self.inner.counterparty_pubkeys().unwrap(), secp_ctx
416 ).expect("derived different per-tx keys or built transaction")
420 /// The state used by [`TestChannelSigner`] in order to enforce policy checks
422 /// This structure is maintained by KeysInterface since we may have multiple copies of
423 /// the signer and they must coordinate their state.
425 pub struct EnforcementState {
426 /// The last counterparty commitment number we signed, backwards counting
427 pub last_counterparty_commitment: u64,
428 /// The last counterparty commitment they revoked, backwards counting
429 pub last_counterparty_revoked_commitment: u64,
430 /// The last holder commitment number we revoked, backwards counting
431 pub last_holder_revoked_commitment: u64,
432 /// The last validated holder commitment number, backwards counting
433 pub last_holder_commitment: u64,
436 impl EnforcementState {
437 /// Enforcement state for a new channel
438 pub fn new() -> Self {
440 last_counterparty_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
441 last_counterparty_revoked_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
442 last_holder_revoked_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,
443 last_holder_commitment: INITIAL_REVOKED_COMMITMENT_NUMBER,