From 8e61b5f4827485869b124fd9cf8d3ce565c98e75 Mon Sep 17 00:00:00 2001 From: Wilmer Paulino Date: Tue, 30 Jan 2024 14:45:46 -0800 Subject: [PATCH] Allow holder commitment and HTLC signature requests to fail As part of the ongoing async signer work, our holder signatures must also be capable of being obtained asynchronously. We expose a new `ChannelMonitor::signer_unblocked` method to retry pending onchain claims by re-signing and rebroadcasting transactions. Unfortunately, we cannot retry said claims without them being registered first, so if we're not able to obtain the signature synchronously, we must return the transaction as unsigned and ensure it is not broadcast. --- lightning/src/chain/chainmonitor.rs | 21 ++++ lightning/src/chain/channelmonitor.rs | 34 +++++- lightning/src/chain/onchaintx.rs | 90 +++++++++------ lightning/src/chain/package.rs | 28 +++-- lightning/src/chain/transaction.rs | 11 +- lightning/src/ln/async_signer_tests.rs | 128 +++++++++++++++++++++- lightning/src/ln/channel.rs | 3 + lightning/src/ln/functional_test_utils.rs | 36 ++++-- lightning/src/sign/ecdsa.rs | 35 ++++++ lightning/src/util/test_channel_signer.rs | 16 ++- lightning/src/util/test_utils.rs | 12 +- 11 files changed, 349 insertions(+), 65 deletions(-) diff --git a/lightning/src/chain/chainmonitor.rs b/lightning/src/chain/chainmonitor.rs index 0e8a027897d..015b3dacfc3 100644 --- a/lightning/src/chain/chainmonitor.rs +++ b/lightning/src/chain/chainmonitor.rs @@ -635,6 +635,27 @@ where C::Target: chain::Filter, ) } } + + /// Triggers rebroadcasts of pending claims from force-closed channels after a transaction + /// signature generation failure. + /// + /// `monitor_opt` can be used as a filter to only trigger them for a specific channel monitor. + pub fn signer_unblocked(&self, monitor_opt: Option) { + let monitors = self.monitors.read().unwrap(); + if let Some(funding_txo) = monitor_opt { + if let Some(monitor_holder) = monitors.get(&funding_txo) { + monitor_holder.monitor.signer_unblocked( + &*self.broadcaster, &*self.fee_estimator, &self.logger + ) + } + } else { + for (_, monitor_holder) in &*monitors { + monitor_holder.monitor.signer_unblocked( + &*self.broadcaster, &*self.fee_estimator, &self.logger + ) + } + } + } } impl diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs index 1cfcc3a4b87..75271637d3c 100644 --- a/lightning/src/chain/channelmonitor.rs +++ b/lightning/src/chain/channelmonitor.rs @@ -1769,6 +1769,25 @@ impl ChannelMonitor { ); } + /// Triggers rebroadcasts of pending claims from a force-closed channel after a transaction + /// signature generation failure. + pub fn signer_unblocked( + &self, broadcaster: B, fee_estimator: F, logger: &L, + ) + where + B::Target: BroadcasterInterface, + F::Target: FeeEstimator, + L::Target: Logger, + { + let fee_estimator = LowerBoundedFeeEstimator::new(fee_estimator); + let mut inner = self.inner.lock().unwrap(); + let logger = WithChannelMonitor::from_impl(logger, &*inner); + let current_height = inner.best_block.height; + inner.onchain_tx_handler.rebroadcast_pending_claims( + current_height, FeerateStrategy::RetryPrevious, &broadcaster, &fee_estimator, &logger, + ); + } + /// Returns the descriptors for relevant outputs (i.e., those that we can spend) within the /// transaction if they exist and the transaction has at least [`ANTI_REORG_DELAY`] /// confirmations. For [`SpendableOutputDescriptor::DelayedPaymentOutput`] descriptors to be @@ -1811,6 +1830,12 @@ impl ChannelMonitor { pub fn set_counterparty_payment_script(&self, script: ScriptBuf) { self.inner.lock().unwrap().counterparty_payment_script = script; } + + #[cfg(test)] + pub fn do_signer_call ()>(&self, mut f: F) { + let inner = self.inner.lock().unwrap(); + f(&inner.onchain_tx_handler.signer); + } } impl ChannelMonitorImpl { @@ -3526,9 +3551,12 @@ impl ChannelMonitorImpl { continue; } } else { None }; - if let Some(htlc_tx) = self.onchain_tx_handler.get_fully_signed_htlc_tx( - &::bitcoin::OutPoint { txid, vout }, &preimage) { - holder_transactions.push(htlc_tx); + if let Some(htlc_tx) = self.onchain_tx_handler.get_maybe_signed_htlc_tx( + &::bitcoin::OutPoint { txid, vout }, &preimage + ) { + if htlc_tx.is_fully_signed() { + holder_transactions.push(htlc_tx.0); + } } } } diff --git a/lightning/src/chain/onchaintx.rs b/lightning/src/chain/onchaintx.rs index a629ecdefc2..6c29d147f02 100644 --- a/lightning/src/chain/onchaintx.rs +++ b/lightning/src/chain/onchaintx.rs @@ -31,6 +31,7 @@ use crate::chain::ClaimId; use crate::chain::chaininterface::{ConfirmationTarget, FeeEstimator, BroadcasterInterface, LowerBoundedFeeEstimator}; use crate::chain::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER}; use crate::chain::package::{PackageSolvingData, PackageTemplate}; +use crate::chain::transaction::MaybeSignedTransaction; use crate::util::logger::Logger; use crate::util::ser::{Readable, ReadableArgs, MaybeReadable, UpgradableRequired, Writer, Writeable, VecWriter}; @@ -204,14 +205,16 @@ pub(crate) enum ClaimEvent { /// control) onchain. pub(crate) enum OnchainClaim { /// A finalized transaction pending confirmation spending the output to claim. - Tx(Transaction), + Tx(MaybeSignedTransaction), /// An event yielded externally to signal additional inputs must be added to a transaction /// pending confirmation spending the output to claim. Event(ClaimEvent), } -/// Represents the different feerates a pending request can use when generating a claim. +/// Represents the different feerate strategies a pending request can use when generating a claim. pub(crate) enum FeerateStrategy { + /// We must reuse the most recently used feerate, if any. + RetryPrevious, /// We must pick the highest between the most recently used and the current feerate estimate. HighestOfPreviousOrNew, /// We must force a bump of the most recently used feerate, either by using the current feerate @@ -506,9 +509,13 @@ impl OnchainTxHandler } match claim { OnchainClaim::Tx(tx) => { - let log_start = if bumped_feerate { "Broadcasting RBF-bumped" } else { "Rebroadcasting" }; - log_info!(logger, "{} onchain {}", log_start, log_tx!(tx)); - broadcaster.broadcast_transactions(&[&tx]); + if tx.is_fully_signed() { + let log_start = if bumped_feerate { "Broadcasting RBF-bumped" } else { "Rebroadcasting" }; + log_info!(logger, "{} onchain {}", log_start, log_tx!(tx.0)); + broadcaster.broadcast_transactions(&[&tx.0]); + } else { + log_info!(logger, "Waiting for signature of unsigned onchain transaction {}", tx.0.txid()); + } }, OnchainClaim::Event(event) => { let log_start = if bumped_feerate { "Yielding fee-bumped" } else { "Replaying" }; @@ -610,11 +617,10 @@ impl OnchainTxHandler ) { assert!(new_feerate != 0); - let transaction = cached_request.finalize_malleable_package( + let transaction = cached_request.maybe_finalize_malleable_package( cur_height, self, output_value, self.destination_script.clone(), logger ).unwrap(); - log_trace!(logger, "...with timer {} and feerate {}", new_timer, new_feerate); - assert!(predicted_weight >= transaction.weight().to_wu()); + assert!(predicted_weight >= transaction.0.weight().to_wu()); return Some((new_timer, new_feerate, OnchainClaim::Tx(transaction))); } } else { @@ -623,7 +629,7 @@ impl OnchainTxHandler // which require external funding. let mut inputs = cached_request.inputs(); debug_assert_eq!(inputs.len(), 1); - let tx = match cached_request.finalize_untractable_package(self, logger) { + let tx = match cached_request.maybe_finalize_untractable_package(self, logger) { Some(tx) => tx, None => return None, }; @@ -634,19 +640,19 @@ impl OnchainTxHandler // Commitment inputs with anchors support are the only untractable inputs supported // thus far that require external funding. PackageSolvingData::HolderFundingOutput(output) => { - debug_assert_eq!(tx.txid(), self.holder_commitment.trust().txid(), + debug_assert_eq!(tx.0.txid(), self.holder_commitment.trust().txid(), "Holder commitment transaction mismatch"); let conf_target = ConfirmationTarget::OnChainSweep; let package_target_feerate_sat_per_1000_weight = cached_request .compute_package_feerate(fee_estimator, conf_target, feerate_strategy); if let Some(input_amount_sat) = output.funding_amount { - let fee_sat = input_amount_sat - tx.output.iter().map(|output| output.value).sum::(); + let fee_sat = input_amount_sat - tx.0.output.iter().map(|output| output.value).sum::(); let commitment_tx_feerate_sat_per_1000_weight = - compute_feerate_sat_per_1000_weight(fee_sat, tx.weight().to_wu()); + compute_feerate_sat_per_1000_weight(fee_sat, tx.0.weight().to_wu()); if commitment_tx_feerate_sat_per_1000_weight >= package_target_feerate_sat_per_1000_weight { - log_debug!(logger, "Pre-signed {} already has feerate {} sat/kW above required {} sat/kW", - log_tx!(tx), commitment_tx_feerate_sat_per_1000_weight, + log_debug!(logger, "Pre-signed commitment {} already has feerate {} sat/kW above required {} sat/kW", + tx.0.txid(), commitment_tx_feerate_sat_per_1000_weight, package_target_feerate_sat_per_1000_weight); return Some((new_timer, 0, OnchainClaim::Tx(tx.clone()))); } @@ -654,7 +660,7 @@ impl OnchainTxHandler // We'll locate an anchor output we can spend within the commitment transaction. let funding_pubkey = &self.channel_transaction_parameters.holder_pubkeys.funding_pubkey; - match chan_utils::get_anchor_output(&tx, funding_pubkey) { + match chan_utils::get_anchor_output(&tx.0, funding_pubkey) { // An anchor output was found, so we should yield a funding event externally. Some((idx, _)) => { // TODO: Use a lower confirmation target when both our and the @@ -664,7 +670,7 @@ impl OnchainTxHandler package_target_feerate_sat_per_1000_weight as u64, OnchainClaim::Event(ClaimEvent::BumpCommitment { package_target_feerate_sat_per_1000_weight, - commitment_tx: tx.clone(), + commitment_tx: tx.0.clone(), anchor_output_idx: idx, }), )) @@ -785,9 +791,13 @@ impl OnchainTxHandler // `OnchainClaim`. let claim_id = match claim { OnchainClaim::Tx(tx) => { - log_info!(logger, "Broadcasting onchain {}", log_tx!(tx)); - broadcaster.broadcast_transactions(&[&tx]); - ClaimId(tx.txid().to_byte_array()) + if tx.is_fully_signed() { + log_info!(logger, "Broadcasting onchain {}", log_tx!(tx.0)); + broadcaster.broadcast_transactions(&[&tx.0]); + } else { + log_info!(logger, "Waiting for signature of unsigned onchain transaction {}", tx.0.txid()); + } + ClaimId(tx.0.txid().to_byte_array()) }, OnchainClaim::Event(claim_event) => { log_info!(logger, "Yielding onchain event to spend inputs {:?}", req.outpoints()); @@ -980,8 +990,13 @@ impl OnchainTxHandler ) { match bump_claim { OnchainClaim::Tx(bump_tx) => { - log_info!(logger, "Broadcasting RBF-bumped onchain {}", log_tx!(bump_tx)); - broadcaster.broadcast_transactions(&[&bump_tx]); + if bump_tx.is_fully_signed() { + log_info!(logger, "Broadcasting RBF-bumped onchain {}", log_tx!(bump_tx.0)); + broadcaster.broadcast_transactions(&[&bump_tx.0]); + } else { + log_info!(logger, "Waiting for signature of RBF-bumped unsigned onchain transaction {}", + bump_tx.0.txid()); + } }, OnchainClaim::Event(claim_event) => { log_info!(logger, "Yielding RBF-bumped onchain event to spend inputs {:?}", request.outpoints()); @@ -1063,8 +1078,12 @@ impl OnchainTxHandler request.set_feerate(new_feerate); match bump_claim { OnchainClaim::Tx(bump_tx) => { - log_info!(logger, "Broadcasting onchain {}", log_tx!(bump_tx)); - broadcaster.broadcast_transactions(&[&bump_tx]); + if bump_tx.is_fully_signed() { + log_info!(logger, "Broadcasting onchain {}", log_tx!(bump_tx.0)); + broadcaster.broadcast_transactions(&[&bump_tx.0]); + } else { + log_info!(logger, "Waiting for signature of unsigned onchain transaction {}", bump_tx.0.txid()); + } }, OnchainClaim::Event(claim_event) => { log_info!(logger, "Yielding onchain event after reorg to spend inputs {:?}", request.outpoints()); @@ -1117,13 +1136,11 @@ impl OnchainTxHandler &self.holder_commitment.trust().built_transaction().transaction } - //TODO: getting lastest holder transactions should be infallible and result in us "force-closing the channel", but we may - // have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after OutboundV1Channel::get_funding_created, - // before providing a initial commitment transaction. For outbound channel, init ChannelMonitor at Channel::funding_signed, there is nothing - // to monitor before. - pub(crate) fn get_fully_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction { - let sig = self.signer.sign_holder_commitment(&self.holder_commitment, &self.secp_ctx).expect("signing holder commitment"); - self.holder_commitment.add_holder_sig(funding_redeemscript, sig) + pub(crate) fn get_maybe_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> MaybeSignedTransaction { + let tx = self.signer.sign_holder_commitment(&self.holder_commitment, &self.secp_ctx) + .map(|sig| self.holder_commitment.add_holder_sig(funding_redeemscript, sig)) + .unwrap_or_else(|_| self.get_unsigned_holder_commitment_tx().clone()); + MaybeSignedTransaction(tx) } #[cfg(any(test, feature="unsafe_revoked_tx_signing"))] @@ -1132,7 +1149,7 @@ impl OnchainTxHandler self.holder_commitment.add_holder_sig(funding_redeemscript, sig) } - pub(crate) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option) -> Option { + pub(crate) fn get_maybe_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option) -> Option { let get_signed_htlc_tx = |holder_commitment: &HolderCommitmentTransaction| { let trusted_tx = holder_commitment.trust(); if trusted_tx.txid() != outp.txid { @@ -1160,11 +1177,12 @@ impl OnchainTxHandler preimage: preimage.clone(), counterparty_sig: counterparty_htlc_sig.clone(), }; - let htlc_sig = self.signer.sign_holder_htlc_transaction(&htlc_tx, 0, &htlc_descriptor, &self.secp_ctx).unwrap(); - htlc_tx.input[0].witness = trusted_tx.build_htlc_input_witness( - htlc_idx, &counterparty_htlc_sig, &htlc_sig, preimage, - ); - Some(htlc_tx) + if let Ok(htlc_sig) = self.signer.sign_holder_htlc_transaction(&htlc_tx, 0, &htlc_descriptor, &self.secp_ctx) { + htlc_tx.input[0].witness = trusted_tx.build_htlc_input_witness( + htlc_idx, &counterparty_htlc_sig, &htlc_sig, preimage, + ); + } + Some(MaybeSignedTransaction(htlc_tx)) }; // Check if the HTLC spends from the current holder commitment first, or the previous. diff --git a/lightning/src/chain/package.rs b/lightning/src/chain/package.rs index 52cdf9f37fd..e304b16ef3e 100644 --- a/lightning/src/chain/package.rs +++ b/lightning/src/chain/package.rs @@ -28,6 +28,7 @@ use crate::ln::features::ChannelTypeFeatures; use crate::ln::channel_keys::{DelayedPaymentBasepoint, HtlcBasepoint}; use crate::ln::msgs::DecodeError; use crate::chain::chaininterface::{FeeEstimator, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT, compute_feerate_sat_per_1000_weight, FEERATE_FLOOR_SATS_PER_KW}; +use crate::chain::transaction::MaybeSignedTransaction; use crate::sign::ecdsa::WriteableEcdsaChannelSigner; use crate::chain::onchaintx::{FeerateStrategy, ExternalHTLCClaim, OnchainTxHandler}; use crate::util::logger::Logger; @@ -633,14 +634,14 @@ impl PackageSolvingData { } true } - fn get_finalized_tx(&self, outpoint: &BitcoinOutPoint, onchain_handler: &mut OnchainTxHandler) -> Option { + fn get_maybe_finalized_tx(&self, outpoint: &BitcoinOutPoint, onchain_handler: &mut OnchainTxHandler) -> Option { match self { PackageSolvingData::HolderHTLCOutput(ref outp) => { debug_assert!(!outp.channel_type_features.supports_anchors_zero_fee_htlc_tx()); - return onchain_handler.get_fully_signed_htlc_tx(outpoint, &outp.preimage); + onchain_handler.get_maybe_signed_htlc_tx(outpoint, &outp.preimage) } PackageSolvingData::HolderFundingOutput(ref outp) => { - return Some(onchain_handler.get_fully_signed_holder_tx(&outp.funding_redeemscript)); + Some(onchain_handler.get_maybe_signed_holder_tx(&outp.funding_redeemscript)) } _ => { panic!("API Error!"); } } @@ -908,10 +909,10 @@ impl PackageTemplate { } htlcs } - pub(crate) fn finalize_malleable_package( + pub(crate) fn maybe_finalize_malleable_package( &self, current_height: u32, onchain_handler: &mut OnchainTxHandler, value: u64, destination_script: ScriptBuf, logger: &L - ) -> Option { + ) -> Option { debug_assert!(self.is_malleable()); let mut bumped_tx = Transaction { version: 2, @@ -927,19 +928,17 @@ impl PackageTemplate { } for (i, (outpoint, out)) in self.inputs.iter().enumerate() { log_debug!(logger, "Adding claiming input for outpoint {}:{}", outpoint.txid, outpoint.vout); - if !out.finalize_input(&mut bumped_tx, i, onchain_handler) { return None; } + if !out.finalize_input(&mut bumped_tx, i, onchain_handler) { continue; } } - log_debug!(logger, "Finalized transaction {} ready to broadcast", bumped_tx.txid()); - Some(bumped_tx) + Some(MaybeSignedTransaction(bumped_tx)) } - pub(crate) fn finalize_untractable_package( + pub(crate) fn maybe_finalize_untractable_package( &self, onchain_handler: &mut OnchainTxHandler, logger: &L, - ) -> Option { + ) -> Option { debug_assert!(!self.is_malleable()); if let Some((outpoint, outp)) = self.inputs.first() { - if let Some(final_tx) = outp.get_finalized_tx(outpoint, onchain_handler) { + if let Some(final_tx) = outp.get_maybe_finalized_tx(outpoint, onchain_handler) { log_debug!(logger, "Adding claiming input for outpoint {}:{}", outpoint.txid, outpoint.vout); - log_debug!(logger, "Finalized transaction {} ready to broadcast", final_tx.txid()); return Some(final_tx); } return None; @@ -996,6 +995,7 @@ impl PackageTemplate { if self.feerate_previous != 0 { let previous_feerate = self.feerate_previous.try_into().unwrap_or(u32::max_value()); match feerate_strategy { + FeerateStrategy::RetryPrevious => previous_feerate, FeerateStrategy::HighestOfPreviousOrNew => cmp::max(previous_feerate, feerate_estimate), FeerateStrategy::ForceBump => if feerate_estimate > previous_feerate { feerate_estimate @@ -1141,6 +1141,10 @@ where // If old feerate inferior to actual one given back by Fee Estimator, use it to compute new fee... let (new_fee, new_feerate) = if let Some((new_fee, new_feerate)) = compute_fee_from_spent_amounts(input_amounts, predicted_weight, fee_estimator, logger) { match feerate_strategy { + FeerateStrategy::RetryPrevious => { + let previous_fee = previous_feerate * predicted_weight / 1000; + (previous_fee, previous_feerate) + }, FeerateStrategy::HighestOfPreviousOrNew => if new_feerate > previous_feerate { (new_fee, new_feerate) } else { diff --git a/lightning/src/chain/transaction.rs b/lightning/src/chain/transaction.rs index 17815207a8d..7a447dd5d90 100644 --- a/lightning/src/chain/transaction.rs +++ b/lightning/src/chain/transaction.rs @@ -58,7 +58,7 @@ pub struct OutPoint { impl OutPoint { /// Converts this OutPoint into the OutPoint field as used by rust-bitcoin /// - /// This is not exported to bindings users as the same type is used universally in the C bindings + /// This is not exported to bindings users as the same type is used universally in the C bindings /// for all outpoints pub fn into_bitcoin_outpoint(self) -> BitcoinOutPoint { BitcoinOutPoint { @@ -76,6 +76,15 @@ impl core::fmt::Display for OutPoint { impl_writeable!(OutPoint, { txid, index }); +#[derive(Debug, Clone)] +pub(crate) struct MaybeSignedTransaction(pub Transaction); + +impl MaybeSignedTransaction { + pub fn is_fully_signed(&self) -> bool { + !self.0.input.iter().any(|input| input.witness.is_empty()) + } +} + #[cfg(test)] mod tests { use crate::chain::transaction::OutPoint; diff --git a/lightning/src/ln/async_signer_tests.rs b/lightning/src/ln/async_signer_tests.rs index 0f51bea0d36..10f4239a188 100644 --- a/lightning/src/ln/async_signer_tests.rs +++ b/lightning/src/ln/async_signer_tests.rs @@ -10,7 +10,12 @@ //! Tests for asynchronous signing. These tests verify that the channel state machine behaves //! properly with a signer implementation that asynchronously derives signatures. -use crate::events::{Event, MessageSendEvent, MessageSendEventsProvider}; +use bitcoin::{Transaction, TxOut, TxIn, Amount}; +use bitcoin::blockdata::locktime::absolute::LockTime; + +use crate::chain::channelmonitor::LATENCY_GRACE_PERIOD_BLOCKS; +use crate::events::bump_transaction::WalletSource; +use crate::events::{Event, MessageSendEvent, MessageSendEventsProvider, ClosureReason}; use crate::ln::functional_test_utils::*; use crate::ln::msgs::ChannelMessageHandler; use crate::ln::channelmanager::{PaymentId, RecipientOnionFields}; @@ -321,3 +326,124 @@ fn test_async_commitment_signature_for_peer_disconnect() { }; } } + +fn do_test_async_holder_signatures(anchors: bool, remote_commitment: bool) { + // Ensures that we can obtain holder signatures for commitment and HTLC transactions + // asynchronously by allowing their retrieval to fail and retrying via + // `ChannelMonitor::signer_unblocked`. + let mut config = test_default_channel_config(); + if anchors { + config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true; + config.manually_accept_inbound_channels = true; + } + + let chanmon_cfgs = create_chanmon_cfgs(2); + let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); + let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[Some(config), Some(config)]); + let nodes = create_network(2, &node_cfgs, &node_chanmgrs); + + let closing_node = if remote_commitment { &nodes[1] } else { &nodes[0] }; + let coinbase_tx = Transaction { + version: 2, + lock_time: LockTime::ZERO, + input: vec![TxIn { ..Default::default() }], + output: vec![ + TxOut { + value: Amount::ONE_BTC.to_sat(), + script_pubkey: closing_node.wallet_source.get_change_script().unwrap(), + }, + ], + }; + if anchors { + *nodes[0].fee_estimator.sat_per_kw.lock().unwrap() *= 2; + *nodes[1].fee_estimator.sat_per_kw.lock().unwrap() *= 2; + closing_node.wallet_source.add_utxo(bitcoin::OutPoint { txid: coinbase_tx.txid(), vout: 0 }, coinbase_tx.output[0].value); + } + + // Route an HTLC and set the signer as unavailable. + let (_, _, chan_id, funding_tx) = create_announced_chan_between_nodes(&nodes, 0, 1); + route_payment(&nodes[0], &[&nodes[1]], 1_000_000); + + nodes[0].set_channel_signer_available(&nodes[1].node.get_our_node_id(), &chan_id, false); + + if remote_commitment { + // Make the counterparty broadcast its latest commitment. + nodes[1].node.force_close_broadcasting_latest_txn(&chan_id, &nodes[0].node.get_our_node_id()).unwrap(); + check_added_monitors(&nodes[1], 1); + check_closed_broadcast(&nodes[1], 1, true); + check_closed_event(&nodes[1], 1, ClosureReason::HolderForceClosed, false, &[nodes[0].node.get_our_node_id()], 100_000); + } else { + // We'll connect blocks until the sender has to go onchain to time out the HTLC. + connect_blocks(&nodes[0], TEST_FINAL_CLTV + LATENCY_GRACE_PERIOD_BLOCKS + 1); + + // No transaction should be broadcast since the signer is not available yet. + assert!(nodes[0].tx_broadcaster.txn_broadcast().is_empty()); + assert!(nodes[0].chain_monitor.chain_monitor.get_and_clear_pending_events().is_empty()); + + // Mark it as available now, we should see the signed commitment transaction. + nodes[0].set_channel_signer_available(&nodes[1].node.get_our_node_id(), &chan_id, true); + get_monitor!(nodes[0], chan_id).signer_unblocked(nodes[0].tx_broadcaster, nodes[0].fee_estimator, &nodes[0].logger); + } + + let commitment_tx = { + let mut txn = closing_node.tx_broadcaster.txn_broadcast(); + if anchors || remote_commitment { + assert_eq!(txn.len(), 1); + check_spends!(txn[0], funding_tx); + txn.remove(0) + } else { + assert_eq!(txn.len(), 2); + if txn[0].input[0].previous_output.txid == funding_tx.txid() { + check_spends!(txn[0], funding_tx); + check_spends!(txn[1], txn[0]); + txn.remove(0) + } else { + check_spends!(txn[1], funding_tx); + check_spends!(txn[0], txn[1]); + txn.remove(1) + } + } + }; + + // Mark it as unavailable again to now test the HTLC transaction. We'll mine the commitment such + // that the HTLC transaction is retried. + nodes[0].set_channel_signer_available(&nodes[1].node.get_our_node_id(), &chan_id, false); + mine_transaction(&nodes[0], &commitment_tx); + + check_added_monitors(&nodes[0], 1); + check_closed_broadcast(&nodes[0], 1, true); + check_closed_event(&nodes[0], 1, ClosureReason::CommitmentTxConfirmed, false, &[nodes[1].node.get_our_node_id()], 100_000); + + // If the counterparty broadcast its latest commitment, we need to mine enough blocks for the + // HTLC timeout. + if remote_commitment { + connect_blocks(&nodes[0], TEST_FINAL_CLTV); + } + + // No HTLC transaction should be broadcast as the signer is not available yet. + if anchors && !remote_commitment { + handle_bump_htlc_event(&nodes[0], 1); + } + assert!(nodes[0].tx_broadcaster.txn_broadcast().is_empty()); + + // Mark it as available now, we should see the signed HTLC transaction. + nodes[0].set_channel_signer_available(&nodes[1].node.get_our_node_id(), &chan_id, true); + get_monitor!(nodes[0], chan_id).signer_unblocked(nodes[0].tx_broadcaster, nodes[0].fee_estimator, &nodes[0].logger); + + if anchors && !remote_commitment { + handle_bump_htlc_event(&nodes[0], 1); + } + { + let txn = nodes[0].tx_broadcaster.txn_broadcast(); + assert_eq!(txn.len(), 1); + check_spends!(txn[0], commitment_tx, coinbase_tx); + } +} + +#[test] +fn test_async_holder_signatures() { + do_test_async_holder_signatures(false, false); + do_test_async_holder_signatures(false, true); + do_test_async_holder_signatures(true, false); + do_test_async_holder_signatures(true, true); +} diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index 31989a011a9..ac409b2c666 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -1492,7 +1492,10 @@ pub(super) struct ChannelContext where SP::Target: SignerProvider { /// The unique identifier used to re-derive the private key material for the channel through /// [`SignerProvider::derive_channel_signer`]. + #[cfg(not(test))] channel_keys_id: [u8; 32], + #[cfg(test)] + pub channel_keys_id: [u8; 32], /// If we can't release a [`ChannelMonitorUpdate`] until some external action completes, we /// store it here and only release it to the `ChannelManager` once it asks for it. diff --git a/lightning/src/ln/functional_test_utils.rs b/lightning/src/ln/functional_test_utils.rs index ffa79669ea7..31a258d8449 100644 --- a/lightning/src/ln/functional_test_utils.rs +++ b/lightning/src/ln/functional_test_utils.rs @@ -487,16 +487,38 @@ impl<'a, 'b, 'c> Node<'a, 'b, 'c> { /// `release_commitment_secret` are affected by this setting. #[cfg(test)] pub fn set_channel_signer_available(&self, peer_id: &PublicKey, chan_id: &ChannelId, available: bool) { + use crate::sign::ChannelSigner; + log_debug!(self.logger, "Setting channel signer for {} as available={}", chan_id, available); + let per_peer_state = self.node.per_peer_state.read().unwrap(); let chan_lock = per_peer_state.get(peer_id).unwrap().lock().unwrap(); - let signer = (|| { - match chan_lock.channel_by_id.get(chan_id) { - Some(phase) => phase.context().get_signer(), - None => panic!("Couldn't find a channel with id {}", chan_id), + + let mut channel_keys_id = None; + if let Some(chan) = chan_lock.channel_by_id.get(chan_id).map(|phase| phase.context()) { + chan.get_signer().as_ecdsa().unwrap().set_available(available); + channel_keys_id = Some(chan.channel_keys_id); + } + + let mut monitor = None; + for (funding_txo, channel_id) in self.chain_monitor.chain_monitor.list_monitors() { + if *chan_id == channel_id { + monitor = self.chain_monitor.chain_monitor.get_monitor(funding_txo).ok(); } - })(); - log_debug!(self.logger, "Setting channel signer for {} as available={}", chan_id, available); - signer.as_ecdsa().unwrap().set_available(available); + } + if let Some(monitor) = monitor { + monitor.do_signer_call(|signer| { + channel_keys_id = channel_keys_id.or(Some(signer.inner.channel_keys_id())); + signer.set_available(available) + }); + } + + if available { + self.keys_manager.unavailable_signers.lock().unwrap() + .remove(channel_keys_id.as_ref().unwrap()); + } else { + self.keys_manager.unavailable_signers.lock().unwrap() + .insert(channel_keys_id.unwrap()); + } } } diff --git a/lightning/src/sign/ecdsa.rs b/lightning/src/sign/ecdsa.rs index 2e98213c182..073b7acb48a 100644 --- a/lightning/src/sign/ecdsa.rs +++ b/lightning/src/sign/ecdsa.rs @@ -51,6 +51,13 @@ pub trait EcdsaChannelSigner: ChannelSigner { /// This may be called multiple times for the same transaction. /// /// An external signer implementation should check that the commitment has not been revoked. + /// + /// An `Err` can be returned to signal that the signer is unavailable/cannot produce a valid + /// signature and should be retried later. Once the signer is ready to provide a signature after + /// previously returning an `Err`, [`ChannelMonitor::signer_unblocked`] must be called on its + /// monitor. + /// + /// [`ChannelMonitor::signer_unblocked`]: crate::chain::channelmonitor::ChannelMonitor::signer_unblocked // // TODO: Document the things someone using this interface should enforce before signing. fn sign_holder_commitment(&self, commitment_tx: &HolderCommitmentTransaction, @@ -76,6 +83,11 @@ pub trait EcdsaChannelSigner: ChannelSigner { /// revoked the state which they eventually broadcast. It's not a _holder_ secret key and does /// not allow the spending of any funds by itself (you need our holder `revocation_secret` to do /// so). + /// + /// An `Err` can be returned to signal that the signer is unavailable/cannot produce a valid + /// signature and should be retried later. Once the signer is ready to provide a signature after + /// previously returning an `Err`, [`ChannelMonitor::signer_unblocked`] must be called on its + /// monitor. fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1 ) -> Result; @@ -97,6 +109,11 @@ pub trait EcdsaChannelSigner: ChannelSigner { /// /// `htlc` holds HTLC elements (hash, timelock), thus changing the format of the witness script /// (which is committed to in the BIP 143 signatures). + /// + /// An `Err` can be returned to signal that the signer is unavailable/cannot produce a valid + /// signature and should be retried later. Once the signer is ready to provide a signature after + /// previously returning an `Err`, [`ChannelMonitor::signer_unblocked`] must be called on its + /// monitor. fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result; @@ -108,8 +125,14 @@ pub trait EcdsaChannelSigner: ChannelSigner { /// [`ChannelMonitor`] [replica](https://github.com/lightningdevkit/rust-lightning/blob/main/GLOSSARY.md#monitor-replicas) /// broadcasts it before receiving the update for the latest commitment transaction. /// + /// An `Err` can be returned to signal that the signer is unavailable/cannot produce a valid + /// signature and should be retried later. Once the signer is ready to provide a signature after + /// previously returning an `Err`, [`ChannelMonitor::signer_unblocked`] must be called on its + /// monitor. + /// /// [`EcdsaSighashType::All`]: bitcoin::sighash::EcdsaSighashType::All /// [`ChannelMonitor`]: crate::chain::channelmonitor::ChannelMonitor + /// [`ChannelMonitor::signer_unblocked`]: crate::chain::channelmonitor::ChannelMonitor::signer_unblocked fn sign_holder_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor, secp_ctx: &Secp256k1 ) -> Result; @@ -130,6 +153,11 @@ pub trait EcdsaChannelSigner: ChannelSigner { /// detected onchain. It has been generated by our counterparty and is used to derive /// channel state keys, which are then included in the witness script and committed to in the /// BIP 143 signature. + /// + /// An `Err` can be returned to signal that the signer is unavailable/cannot produce a valid + /// signature and should be retried later. Once the signer is ready to provide a signature after + /// previously returning an `Err`, [`ChannelMonitor::signer_unblocked`] must be called on its + /// monitor. fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result; @@ -141,6 +169,13 @@ pub trait EcdsaChannelSigner: ChannelSigner { secp_ctx: &Secp256k1) -> Result; /// Computes the signature for a commitment transaction's anchor output used as an /// input within `anchor_tx`, which spends the commitment transaction, at index `input`. + /// + /// An `Err` can be returned to signal that the signer is unavailable/cannot produce a valid + /// signature and should be retried later. Once the signer is ready to provide a signature after + /// previously returning an `Err`, [`ChannelMonitor::signer_unblocked`] must be called on its + /// monitor. + /// + /// [`ChannelMonitor::signer_unblocked`]: crate::chain::channelmonitor::ChannelMonitor::signer_unblocked fn sign_holder_anchor_input( &self, anchor_tx: &Transaction, input: usize, secp_ctx: &Secp256k1, ) -> Result; diff --git a/lightning/src/util/test_channel_signer.rs b/lightning/src/util/test_channel_signer.rs index a2cbf78b700..bfa3e32c91f 100644 --- a/lightning/src/util/test_channel_signer.rs +++ b/lightning/src/util/test_channel_signer.rs @@ -117,7 +117,6 @@ impl TestChannelSigner { /// When `true`, methods are forwarded to the underlying signer as normal. When `false`, some /// methods will return `Err` indicating that the signer is unavailable. Intended to be used for /// testing asynchronous signing. - #[cfg(test)] pub fn set_available(&self, available: bool) { *self.available.lock().unwrap() = available; } @@ -210,10 +209,16 @@ impl EcdsaChannelSigner for TestChannelSigner { } fn sign_justice_revoked_output(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, secp_ctx: &Secp256k1) -> Result { + if !*self.available.lock().unwrap() { + return Err(()); + } Ok(EcdsaChannelSigner::sign_justice_revoked_output(&self.inner, justice_tx, input, amount, per_commitment_key, secp_ctx).unwrap()) } fn sign_justice_revoked_htlc(&self, justice_tx: &Transaction, input: usize, amount: u64, per_commitment_key: &SecretKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result { + if !*self.available.lock().unwrap() { + return Err(()); + } Ok(EcdsaChannelSigner::sign_justice_revoked_htlc(&self.inner, justice_tx, input, amount, per_commitment_key, htlc, secp_ctx).unwrap()) } @@ -221,6 +226,9 @@ impl EcdsaChannelSigner for TestChannelSigner { &self, htlc_tx: &Transaction, input: usize, htlc_descriptor: &HTLCDescriptor, secp_ctx: &Secp256k1 ) -> Result { + if !*self.available.lock().unwrap() { + return Err(()); + } let state = self.state.lock().unwrap(); if state.last_holder_revoked_commitment - 1 != htlc_descriptor.per_commitment_number && state.last_holder_revoked_commitment - 2 != htlc_descriptor.per_commitment_number @@ -254,6 +262,9 @@ impl EcdsaChannelSigner for TestChannelSigner { } fn sign_counterparty_htlc_transaction(&self, htlc_tx: &Transaction, input: usize, amount: u64, per_commitment_point: &PublicKey, htlc: &HTLCOutputInCommitment, secp_ctx: &Secp256k1) -> Result { + if !*self.available.lock().unwrap() { + return Err(()); + } Ok(EcdsaChannelSigner::sign_counterparty_htlc_transaction(&self.inner, htlc_tx, input, amount, per_commitment_point, htlc, secp_ctx).unwrap()) } @@ -270,6 +281,9 @@ impl EcdsaChannelSigner for TestChannelSigner { // As long as our minimum dust limit is enforced and is greater than our anchor output // value, an anchor output can only have an index within [0, 1]. assert!(anchor_tx.input[input].previous_output.vout == 0 || anchor_tx.input[input].previous_output.vout == 1); + if !*self.available.lock().unwrap() { + return Err(()); + } EcdsaChannelSigner::sign_holder_anchor_input(&self.inner, anchor_tx, input, secp_ctx) } diff --git a/lightning/src/util/test_utils.rs b/lightning/src/util/test_utils.rs index 5346f8ec306..09a8c3a2661 100644 --- a/lightning/src/util/test_utils.rs +++ b/lightning/src/util/test_utils.rs @@ -1164,6 +1164,7 @@ pub struct TestKeysInterface { pub disable_revocation_policy_check: bool, enforcement_states: Mutex>>>, expectations: Mutex>>, + pub unavailable_signers: Mutex>, } impl EntropySource for TestKeysInterface { @@ -1222,7 +1223,11 @@ impl SignerProvider for TestKeysInterface { fn derive_channel_signer(&self, channel_value_satoshis: u64, channel_keys_id: [u8; 32]) -> TestChannelSigner { let keys = self.backing.derive_channel_signer(channel_value_satoshis, channel_keys_id); let state = self.make_enforcement_state_cell(keys.commitment_seed); - TestChannelSigner::new_with_revoked(keys, state, self.disable_revocation_policy_check) + let signer = TestChannelSigner::new_with_revoked(keys, state, self.disable_revocation_policy_check); + if self.unavailable_signers.lock().unwrap().contains(&channel_keys_id) { + signer.set_available(false); + } + signer } fn read_chan_signer(&self, buffer: &[u8]) -> Result { @@ -1260,6 +1265,7 @@ impl TestKeysInterface { disable_revocation_policy_check: false, enforcement_states: Mutex::new(new_hash_map()), expectations: Mutex::new(None), + unavailable_signers: Mutex::new(new_hash_set()), } } @@ -1273,9 +1279,7 @@ impl TestKeysInterface { } pub fn derive_channel_keys(&self, channel_value_satoshis: u64, id: &[u8; 32]) -> TestChannelSigner { - let keys = self.backing.derive_channel_keys(channel_value_satoshis, id); - let state = self.make_enforcement_state_cell(keys.commitment_seed); - TestChannelSigner::new_with_revoked(keys, state, self.disable_revocation_policy_check) + self.derive_channel_signer(channel_value_satoshis, *id) } fn make_enforcement_state_cell(&self, commitment_seed: [u8; 32]) -> Arc> {