X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fonchaintx.rs;h=83dc968c6ca549cdb8a4f49978445f583664490b;hb=a89996564cdc9e8708b147b2a5e7b11b59adfc8e;hp=146a4d57c8b27d68bef808a45e3ec6789c464a9b;hpb=9c9c88147e6a8fa637dc048f764ab8ecfea200d4;p=rust-lightning

diff --git a/lightning/src/ln/onchaintx.rs b/lightning/src/ln/onchaintx.rs
index 146a4d57..83dc968c 100644
--- a/lightning/src/ln/onchaintx.rs
+++ b/lightning/src/ln/onchaintx.rs
@@ -27,20 +27,40 @@ use ln::chan_utils;
 use ln::chan_utils::{TxCreationKeys, ChannelTransactionParameters, HolderCommitmentTransaction};
 use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
 use chain::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
-use chain::keysinterface::ChannelKeys;
+use chain::keysinterface::{Sign, KeysInterface};
 use util::logger::Logger;
-use util::ser::{Readable, Writer, Writeable};
+use util::ser::{Readable, ReadableArgs, Writer, Writeable, VecWriter};
 use util::byte_utils;
 
-use std::collections::{HashMap, hash_map};
+use std::collections::HashMap;
 use std::cmp;
 use std::ops::Deref;
+use std::mem::replace;
 
 const MAX_ALLOC_SIZE: usize = 64*1024;
 
+/// An entry for an [`OnchainEvent`], stating the block height when the event was observed.
+///
+/// Used to determine when the on-chain event can be considered safe from a chain reorganization.
+#[derive(PartialEq)]
+struct OnchainEventEntry {
+	height: u32,
+	event: OnchainEvent,
+}
+
+impl OnchainEventEntry {
+	fn confirmation_threshold(&self) -> u32 {
+		self.height + ANTI_REORG_DELAY - 1
+	}
+
+	fn has_reached_confirmation_threshold(&self, height: u32) -> bool {
+		self.confirmation_threshold() == height
+	}
+}
+
 /// Upon discovering of some classes of onchain tx by ChannelMonitor, we may have to take actions on it
 /// once they mature to enough confirmations (ANTI_REORG_DELAY)
-#[derive(Clone, PartialEq)]
+#[derive(PartialEq)]
 enum OnchainEvent {
 	/// Outpoint under claim process by our own tx, once this one get enough confirmations, we remove it from
 	/// bump-txn candidate buffer.
@@ -239,9 +259,9 @@ impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
 
 /// OnchainTxHandler receives claiming requests, aggregates them if it's sound, broadcast and
 /// do RBF bumping if possible.
-pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
+pub struct OnchainTxHandler<ChannelSigner: Sign> {
 	destination_script: Script,
-	holder_commitment: Option<HolderCommitmentTransaction>,
+	holder_commitment: HolderCommitmentTransaction,
 	// holder_htlc_sigs and prev_holder_htlc_sigs are in the order as they appear in the commitment
 	// transaction outputs (hence the Option<>s inside the Vec). The first usize is the index in
 	// the set of HTLCs in the HolderCommitmentTransaction.
@@ -249,7 +269,7 @@ pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
 	prev_holder_commitment: Option<HolderCommitmentTransaction>,
 	prev_holder_htlc_sigs: Option<Vec<Option<(usize, Signature)>>>,
 
-	key_storage: ChanSigner,
+	signer: ChannelSigner,
 	pub(crate) channel_transaction_parameters: ChannelTransactionParameters,
 
 	// Used to track claiming requests. If claim tx doesn't confirm before height timer expiration we need to bump
@@ -279,14 +299,14 @@ pub struct OnchainTxHandler<ChanSigner: ChannelKeys> {
 	#[cfg(not(test))]
 	claimable_outpoints: HashMap<BitcoinOutPoint, (Txid, u32)>,
 
-	onchain_events_waiting_threshold_conf: HashMap<u32, Vec<OnchainEvent>>,
+	onchain_events_waiting_threshold_conf: Vec<OnchainEventEntry>,
 
 	latest_height: u32,
 
 	secp_ctx: Secp256k1<secp256k1::All>,
 }
 
-impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
+impl<ChannelSigner: Sign> OnchainTxHandler<ChannelSigner> {
 	pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
 		self.destination_script.write(writer)?;
 		self.holder_commitment.write(writer)?;
@@ -294,9 +314,15 @@ impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 		self.prev_holder_commitment.write(writer)?;
 		self.prev_holder_htlc_sigs.write(writer)?;
 
-		self.key_storage.write(writer)?;
 		self.channel_transaction_parameters.write(writer)?;
 
+		let mut key_data = VecWriter(Vec::new());
+		self.signer.write(&mut key_data)?;
+		assert!(key_data.0.len() < std::usize::MAX);
+		assert!(key_data.0.len() < std::u32::MAX as usize);
+		(key_data.0.len() as u32).write(writer)?;
+		writer.write_all(&key_data.0[..])?;
+
 		writer.write_all(&byte_utils::be64_to_array(self.pending_claim_requests.len() as u64))?;
 		for (ref ancestor_claim_txid, claim_tx_data) in self.pending_claim_requests.iter() {
 			ancestor_claim_txid.write(writer)?;
@@ -311,20 +337,17 @@ impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 		}
 
 		writer.write_all(&byte_utils::be64_to_array(self.onchain_events_waiting_threshold_conf.len() as u64))?;
-		for (ref target, ref events) in self.onchain_events_waiting_threshold_conf.iter() {
-			writer.write_all(&byte_utils::be32_to_array(**target))?;
-			writer.write_all(&byte_utils::be64_to_array(events.len() as u64))?;
-			for ev in events.iter() {
-				match *ev {
-					OnchainEvent::Claim { ref claim_request } => {
-						writer.write_all(&[0; 1])?;
-						claim_request.write(writer)?;
-					},
-					OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
-						writer.write_all(&[1; 1])?;
-						outpoint.write(writer)?;
-						input_material.write(writer)?;
-					}
+		for ref entry in self.onchain_events_waiting_threshold_conf.iter() {
+			writer.write_all(&byte_utils::be32_to_array(entry.height))?;
+			match entry.event {
+				OnchainEvent::Claim { ref claim_request } => {
+					writer.write_all(&[0; 1])?;
+					claim_request.write(writer)?;
+				},
+				OnchainEvent::ContentiousOutpoint { ref outpoint, ref input_material } => {
+					writer.write_all(&[1; 1])?;
+					outpoint.write(writer)?;
+					input_material.write(writer)?;
 				}
 			}
 		}
@@ -333,8 +356,8 @@ impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 	}
 }
 
-impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigner> {
-	fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+impl<'a, K: KeysInterface> ReadableArgs<&'a K> for OnchainTxHandler<K::Signer> {
+	fn read<R: ::std::io::Read>(reader: &mut R, keys_manager: &'a K) -> Result<Self, DecodeError> {
 		let destination_script = Readable::read(reader)?;
 
 		let holder_commitment = Readable::read(reader)?;
@@ -342,9 +365,19 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigne
 		let prev_holder_commitment = Readable::read(reader)?;
 		let prev_holder_htlc_sigs = Readable::read(reader)?;
 
-		let key_storage = Readable::read(reader)?;
 		let channel_parameters = Readable::read(reader)?;
 
+		let keys_len: u32 = Readable::read(reader)?;
+		let mut keys_data = Vec::with_capacity(cmp::min(keys_len as usize, MAX_ALLOC_SIZE));
+		while keys_data.len() != keys_len as usize {
+			// Read 1KB at a time to avoid accidentally allocating 4GB on corrupted channel keys
+			let mut data = [0; 1024];
+			let read_slice = &mut data[0..cmp::min(1024, keys_len as usize - keys_data.len())];
+			reader.read_exact(read_slice)?;
+			keys_data.extend_from_slice(read_slice);
+		}
+		let signer = keys_manager.read_chan_signer(&keys_data)?;
+
 		let pending_claim_requests_len: u64 = Readable::read(reader)?;
 		let mut pending_claim_requests = HashMap::with_capacity(cmp::min(pending_claim_requests_len as usize, MAX_ALLOC_SIZE / 128));
 		for _ in 0..pending_claim_requests_len {
@@ -360,71 +393,66 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigne
 			claimable_outpoints.insert(outpoint, (ancestor_claim_txid, height));
 		}
 		let waiting_threshold_conf_len: u64 = Readable::read(reader)?;
-		let mut onchain_events_waiting_threshold_conf = HashMap::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
+		let mut onchain_events_waiting_threshold_conf = Vec::with_capacity(cmp::min(waiting_threshold_conf_len as usize, MAX_ALLOC_SIZE / 128));
 		for _ in 0..waiting_threshold_conf_len {
-			let height_target = Readable::read(reader)?;
-			let events_len: u64 = Readable::read(reader)?;
-			let mut events = Vec::with_capacity(cmp::min(events_len as usize, MAX_ALLOC_SIZE / 128));
-			for _ in 0..events_len {
-				let ev = match <u8 as Readable>::read(reader)? {
-					0 => {
-						let claim_request = Readable::read(reader)?;
-						OnchainEvent::Claim {
-							claim_request
-						}
-					},
-					1 => {
-						let outpoint = Readable::read(reader)?;
-						let input_material = Readable::read(reader)?;
-						OnchainEvent::ContentiousOutpoint {
-							outpoint,
-							input_material
-						}
+			let height = Readable::read(reader)?;
+			let event = match <u8 as Readable>::read(reader)? {
+				0 => {
+					let claim_request = Readable::read(reader)?;
+					OnchainEvent::Claim {
+						claim_request
 					}
-					_ => return Err(DecodeError::InvalidValue),
-				};
-				events.push(ev);
-			}
-			onchain_events_waiting_threshold_conf.insert(height_target, events);
+				},
+				1 => {
+					let outpoint = Readable::read(reader)?;
+					let input_material = Readable::read(reader)?;
+					OnchainEvent::ContentiousOutpoint {
+						outpoint,
+						input_material
+					}
+				}
+				_ => return Err(DecodeError::InvalidValue),
+			};
+			onchain_events_waiting_threshold_conf.push(OnchainEventEntry { height, event });
 		}
 		let latest_height = Readable::read(reader)?;
 
+		let mut secp_ctx = Secp256k1::new();
+		secp_ctx.seeded_randomize(&keys_manager.get_secure_random_bytes());
+
 		Ok(OnchainTxHandler {
 			destination_script,
 			holder_commitment,
 			holder_htlc_sigs,
 			prev_holder_commitment,
 			prev_holder_htlc_sigs,
-			key_storage,
+			signer,
 			channel_transaction_parameters: channel_parameters,
 			claimable_outpoints,
 			pending_claim_requests,
 			onchain_events_waiting_threshold_conf,
 			latest_height,
-			secp_ctx: Secp256k1::new(),
+			secp_ctx,
 		})
 	}
 }
 
-impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
-	pub(crate) fn new(destination_script: Script, keys: ChanSigner, channel_parameters: ChannelTransactionParameters) -> Self {
-
-		let key_storage = keys;
-
+impl<ChannelSigner: Sign> OnchainTxHandler<ChannelSigner> {
+	pub(crate) fn new(destination_script: Script, signer: ChannelSigner, channel_parameters: ChannelTransactionParameters, holder_commitment: HolderCommitmentTransaction, secp_ctx: Secp256k1<secp256k1::All>) -> Self {
 		OnchainTxHandler {
 			destination_script,
-			holder_commitment: None,
+			holder_commitment,
 			holder_htlc_sigs: None,
 			prev_holder_commitment: None,
 			prev_holder_htlc_sigs: None,
-			key_storage,
+			signer,
 			channel_transaction_parameters: channel_parameters,
 			pending_claim_requests: HashMap::new(),
 			claimable_outpoints: HashMap::new(),
-			onchain_events_waiting_threshold_conf: HashMap::new(),
+			onchain_events_waiting_threshold_conf: Vec::new(),
 			latest_height: 0,
 
-			secp_ctx: Secp256k1::new(),
+			secp_ctx,
 		}
 	}
 
@@ -474,6 +502,8 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 
 	/// Lightning security model (i.e being able to redeem/timeout HTLC or penalize coutnerparty onchain) lays on the assumption of claim transactions getting confirmed before timelock expiration
 	/// (CSV or CLTV following cases). In case of high-fee spikes, claim tx may stuck in the mempool, so you need to bump its feerate quickly using Replace-By-Fee or Child-Pay-For-Parent.
+	/// Panics if there are signing errors, because signing operations in reaction to on-chain events
+	/// are not expected to fail, and if they do, we may lose funds.
 	fn generate_claim_tx<F: Deref, L: Deref>(&mut self, height: u32, cached_claim_datas: &ClaimTxBumpMaterial, fee_estimator: &F, logger: &L) -> Option<(Option<u32>, u32, Transaction)>
 		where F::Target: FeeEstimator,
 					L::Target: Logger,
@@ -586,45 +616,42 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 			for (i, (outp, per_outp_material)) in cached_claim_datas.per_input_material.iter().enumerate() {
 				match per_outp_material {
 					&InputMaterial::Revoked { ref per_commitment_point, ref counterparty_delayed_payment_base_key, ref counterparty_htlc_base_key, ref per_commitment_key, ref input_descriptor, ref amount, ref htlc, ref on_counterparty_tx_csv } => {
-						if let Ok(chan_keys) = TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, counterparty_delayed_payment_base_key, counterparty_htlc_base_key, &self.key_storage.pubkeys().revocation_basepoint, &self.key_storage.pubkeys().htlc_basepoint) {
+						if let Ok(tx_keys) = TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, counterparty_delayed_payment_base_key, counterparty_htlc_base_key, &self.signer.pubkeys().revocation_basepoint, &self.signer.pubkeys().htlc_basepoint) {
 
 							let witness_script = if let Some(ref htlc) = *htlc {
-								chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key)
+								chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &tx_keys.broadcaster_htlc_key, &tx_keys.countersignatory_htlc_key, &tx_keys.revocation_key)
 							} else {
-								chan_utils::get_revokeable_redeemscript(&chan_keys.revocation_key, *on_counterparty_tx_csv, &chan_keys.broadcaster_delayed_payment_key)
+								chan_utils::get_revokeable_redeemscript(&tx_keys.revocation_key, *on_counterparty_tx_csv, &tx_keys.broadcaster_delayed_payment_key)
 							};
 
-							if let Ok(sig) = self.key_storage.sign_justice_transaction(&bumped_tx, i, *amount, &per_commitment_key, htlc, &self.secp_ctx) {
-								bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
-								bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
-								if htlc.is_some() {
-									bumped_tx.input[i].witness.push(chan_keys.revocation_key.clone().serialize().to_vec());
-								} else {
-									bumped_tx.input[i].witness.push(vec!(1));
-								}
-								bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
-							} else { return None; }
-							//TODO: panic ?
+							let sig = self.signer.sign_justice_transaction(&bumped_tx, i, *amount, &per_commitment_key, htlc, &self.secp_ctx).expect("sign justice tx");
+							bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
+							bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
+							if htlc.is_some() {
+								bumped_tx.input[i].witness.push(tx_keys.revocation_key.clone().serialize().to_vec());
+							} else {
+								bumped_tx.input[i].witness.push(vec!(1));
+							}
+							bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 
 							log_trace!(logger, "Going to broadcast Penalty Transaction {} claiming revoked {} output {} from {} with new feerate {}...", bumped_tx.txid(), if *input_descriptor == InputDescriptors::RevokedOutput { "to_holder" } else if *input_descriptor == InputDescriptors::RevokedOfferedHTLC { "offered" } else if *input_descriptor == InputDescriptors::RevokedReceivedHTLC { "received" } else { "" }, outp.vout, outp.txid, new_feerate);
 						}
 					},
 					&InputMaterial::CounterpartyHTLC { ref per_commitment_point, ref counterparty_delayed_payment_base_key, ref counterparty_htlc_base_key, ref preimage, ref htlc } => {
-						if let Ok(chan_keys) = TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, counterparty_delayed_payment_base_key, counterparty_htlc_base_key, &self.key_storage.pubkeys().revocation_basepoint, &self.key_storage.pubkeys().htlc_basepoint) {
-							let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &chan_keys.broadcaster_htlc_key, &chan_keys.countersignatory_htlc_key, &chan_keys.revocation_key);
+						if let Ok(tx_keys) = TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, counterparty_delayed_payment_base_key, counterparty_htlc_base_key, &self.signer.pubkeys().revocation_basepoint, &self.signer.pubkeys().htlc_basepoint) {
+							let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &tx_keys.broadcaster_htlc_key, &tx_keys.countersignatory_htlc_key, &tx_keys.revocation_key);
 
 							if !preimage.is_some() { bumped_tx.lock_time = htlc.cltv_expiry }; // Right now we don't aggregate time-locked transaction, if we do we should set lock_time before to avoid breaking hash computation
-							if let Ok(sig) = self.key_storage.sign_counterparty_htlc_transaction(&bumped_tx, i, &htlc.amount_msat / 1000, &per_commitment_point, htlc, &self.secp_ctx) {
-								bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
-								bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
-								if let &Some(preimage) = preimage {
-									bumped_tx.input[i].witness.push(preimage.0.to_vec());
-								} else {
-									// Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
-									bumped_tx.input[i].witness.push(vec![]);
-								}
-								bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
+							let sig = self.signer.sign_counterparty_htlc_transaction(&bumped_tx, i, &htlc.amount_msat / 1000, &per_commitment_point, htlc, &self.secp_ctx).expect("sign counterparty HTLC tx");
+							bumped_tx.input[i].witness.push(sig.serialize_der().to_vec());
+							bumped_tx.input[i].witness[0].push(SigHashType::All as u8);
+							if let &Some(preimage) = preimage {
+								bumped_tx.input[i].witness.push(preimage.0.to_vec());
+							} else {
+								// Due to BIP146 (MINIMALIF) this must be a zero-length element to relay.
+								bumped_tx.input[i].witness.push(vec![]);
 							}
+							bumped_tx.input[i].witness.push(witness_script.clone().into_bytes());
 							log_trace!(logger, "Going to broadcast Claim Transaction {} claiming counterparty {} htlc output {} from {} with new feerate {}...", bumped_tx.txid(), if preimage.is_some() { "offered" } else { "received" }, outp.vout, outp.txid, new_feerate);
 						}
 					},
@@ -648,10 +675,10 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 						return None;
 					},
 					&InputMaterial::Funding { ref funding_redeemscript } => {
-						let signed_tx = self.get_fully_signed_holder_tx(funding_redeemscript).unwrap();
+						let signed_tx = self.get_fully_signed_holder_tx(funding_redeemscript);
 						// Timer set to $NEVER given we can't bump tx without anchor outputs
 						log_trace!(logger, "Going to broadcast Holder Transaction {} claiming funding output {} from {}...", signed_tx.txid(), outp.vout, outp.txid);
-						return Some((None, self.holder_commitment.as_ref().unwrap().feerate_per_kw(), signed_tx));
+						return Some((None, self.holder_commitment.feerate_per_kw(), signed_tx));
 					}
 					_ => unreachable!()
 				}
@@ -740,16 +767,12 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 
 						macro_rules! clean_claim_request_after_safety_delay {
 							() => {
-								let new_event = OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() };
-								match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
-									hash_map::Entry::Occupied(mut entry) => {
-										if !entry.get().contains(&new_event) {
-											entry.get_mut().push(new_event);
-										}
-									},
-									hash_map::Entry::Vacant(entry) => {
-										entry.insert(vec![new_event]);
-									}
+								let entry = OnchainEventEntry {
+									height,
+									event: OnchainEvent::Claim { claim_request: first_claim_txid_height.0.clone() }
+								};
+								if !self.onchain_events_waiting_threshold_conf.contains(&entry) {
+									self.onchain_events_waiting_threshold_conf.push(entry);
 								}
 							}
 						}
@@ -783,24 +806,22 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 				}
 			}
 			for (outpoint, input_material) in claimed_outputs_material.drain(..) {
-				let new_event = OnchainEvent::ContentiousOutpoint { outpoint, input_material };
-				match self.onchain_events_waiting_threshold_conf.entry(height + ANTI_REORG_DELAY - 1) {
-					hash_map::Entry::Occupied(mut entry) => {
-						if !entry.get().contains(&new_event) {
-							entry.get_mut().push(new_event);
-						}
-					},
-					hash_map::Entry::Vacant(entry) => {
-						entry.insert(vec![new_event]);
-					}
+				let entry = OnchainEventEntry {
+					height,
+					event: OnchainEvent::ContentiousOutpoint { outpoint, input_material },
+				};
+				if !self.onchain_events_waiting_threshold_conf.contains(&entry) {
+					self.onchain_events_waiting_threshold_conf.push(entry);
 				}
 			}
 		}
 
 		// After security delay, either our claim tx got enough confs or outpoint is definetely out of reach
-		if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&height) {
-			for ev in events {
-				match ev {
+		let onchain_events_waiting_threshold_conf =
+			self.onchain_events_waiting_threshold_conf.drain(..).collect::<Vec<_>>();
+		for entry in onchain_events_waiting_threshold_conf {
+			if entry.has_reached_confirmation_threshold(height) {
+				match entry.event {
 					OnchainEvent::Claim { claim_request } => {
 						// We may remove a whole set of claim outpoints here, as these one may have
 						// been aggregated in a single tx and claimed so atomically
@@ -814,6 +835,8 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 						self.claimable_outpoints.remove(&outpoint);
 					}
 				}
+			} else {
+				self.onchain_events_waiting_threshold_conf.push(entry);
 			}
 		}
 
@@ -846,11 +869,13 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 					L::Target: Logger,
 	{
 		let mut bump_candidates = HashMap::new();
-		if let Some(events) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
-			//- our claim tx on a commitment tx output
-			//- resurect outpoint back in its claimable set and regenerate tx
-			for ev in events {
-				match ev {
+		let onchain_events_waiting_threshold_conf =
+			self.onchain_events_waiting_threshold_conf.drain(..).collect::<Vec<_>>();
+		for entry in onchain_events_waiting_threshold_conf {
+			if entry.height == height {
+				//- our claim tx on a commitment tx output
+				//- resurect outpoint back in its claimable set and regenerate tx
+				match entry.event {
 					OnchainEvent::ContentiousOutpoint { outpoint, input_material } => {
 						if let Some(ancestor_claimable_txid) = self.claimable_outpoints.get(&outpoint) {
 							if let Some(claim_material) = self.pending_claim_requests.get_mut(&ancestor_claimable_txid.0) {
@@ -863,6 +888,8 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 					},
 					_ => {},
 				}
+			} else {
+				self.onchain_events_waiting_threshold_conf.push(entry);
 			}
 		}
 		for (_, claim_material) in bump_candidates.iter_mut() {
@@ -889,21 +916,27 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 	}
 
 	pub(crate) fn provide_latest_holder_tx(&mut self, tx: HolderCommitmentTransaction) {
-		self.prev_holder_commitment = self.holder_commitment.take();
-		self.holder_commitment = Some(tx);
+		self.prev_holder_commitment = Some(replace(&mut self.holder_commitment, tx));
+		self.holder_htlc_sigs = None;
 	}
 
+	// Normally holder HTLCs are signed at the same time as the holder commitment tx.  However,
+	// in some configurations, the holder commitment tx has been signed and broadcast by a
+	// ChannelMonitor replica, so we handle that case here.
 	fn sign_latest_holder_htlcs(&mut self) {
-		if let Some(ref holder_commitment) = self.holder_commitment {
-			if let Ok(sigs) = self.key_storage.sign_holder_commitment_htlc_transactions(holder_commitment, &self.secp_ctx) {
-				self.holder_htlc_sigs = Some(Self::extract_holder_sigs(holder_commitment, sigs));
-			}
+		if self.holder_htlc_sigs.is_none() {
+			let (_sig, sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
+			self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, sigs));
 		}
 	}
 
+	// Normally only the latest commitment tx and HTLCs need to be signed.  However, in some
+	// configurations we may have updated our holder commitment but a replica of the ChannelMonitor
+	// broadcast the previous one before we sync with it.  We handle that case here.
 	fn sign_prev_holder_htlcs(&mut self) {
-		if let Some(ref holder_commitment) = self.prev_holder_commitment {
-			if let Ok(sigs) = self.key_storage.sign_holder_commitment_htlc_transactions(holder_commitment, &self.secp_ctx) {
+		if self.prev_holder_htlc_sigs.is_none() {
+			if let Some(ref holder_commitment) = self.prev_holder_commitment {
+				let (_sig, sigs) = self.signer.sign_holder_commitment_and_htlcs(holder_commitment, &self.secp_ctx).expect("sign previous holder commitment");
 				self.prev_holder_htlc_sigs = Some(Self::extract_holder_sigs(holder_commitment, sigs));
 			}
 		}
@@ -923,50 +956,35 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
 	// have empty holder commitment transaction if a ChannelMonitor is asked to force-close just after Channel::get_outbound_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) -> Option<Transaction> {
-		if let Some(ref mut holder_commitment) = self.holder_commitment {
-			match self.key_storage.sign_holder_commitment(&holder_commitment, &self.secp_ctx) {
-				Ok(sig) => {
-					Some(holder_commitment.add_holder_sig(funding_redeemscript, sig))
-				},
-				Err(_) => return None,
-			}
-		} else {
-			None
-		}
+	pub(crate) fn get_fully_signed_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
+		let (sig, htlc_sigs) = self.signer.sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("signing holder commitment");
+		self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
+		self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
 	}
 
 	#[cfg(any(test, feature="unsafe_revoked_tx_signing"))]
-	pub(crate) fn get_fully_signed_copy_holder_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
-		if let Some(ref mut holder_commitment) = self.holder_commitment {
-			match self.key_storage.sign_holder_commitment(holder_commitment, &self.secp_ctx) {
-				Ok(sig) => {
-					Some(holder_commitment.add_holder_sig(funding_redeemscript, sig))
-				},
-				Err(_) => return None,
-			}
-		} else {
-			None
-		}
+	pub(crate) fn get_fully_signed_copy_holder_tx(&mut self, funding_redeemscript: &Script) -> Transaction {
+		let (sig, htlc_sigs) = self.signer.unsafe_sign_holder_commitment_and_htlcs(&self.holder_commitment, &self.secp_ctx).expect("sign holder commitment");
+		self.holder_htlc_sigs = Some(Self::extract_holder_sigs(&self.holder_commitment, htlc_sigs));
+		self.holder_commitment.add_holder_sig(funding_redeemscript, sig)
 	}
 
 	pub(crate) fn get_fully_signed_htlc_tx(&mut self, outp: &::bitcoin::OutPoint, preimage: &Option<PaymentPreimage>) -> Option<Transaction> {
 		let mut htlc_tx = None;
-		if self.holder_commitment.is_some() {
-			let commitment_txid = self.holder_commitment.as_ref().unwrap().trust().txid();
-			if commitment_txid == outp.txid {
-				self.sign_latest_holder_htlcs();
-				if let &Some(ref htlc_sigs) = &self.holder_htlc_sigs {
-					let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
-					let holder_commitment = self.holder_commitment.as_ref().unwrap();
-					let trusted_tx = holder_commitment.trust();
-					let counterparty_htlc_sig = holder_commitment.counterparty_htlc_sigs[*htlc_idx];
-					htlc_tx = Some(trusted_tx
-						.get_signed_htlc_tx(&self.channel_transaction_parameters.as_holder_broadcastable(), *htlc_idx, &counterparty_htlc_sig, htlc_sig, preimage));
-				}
+		let commitment_txid = self.holder_commitment.trust().txid();
+		// Check if the HTLC spends from the current holder commitment
+		if commitment_txid == outp.txid {
+			self.sign_latest_holder_htlcs();
+			if let &Some(ref htlc_sigs) = &self.holder_htlc_sigs {
+				let &(ref htlc_idx, ref htlc_sig) = htlc_sigs[outp.vout as usize].as_ref().unwrap();
+				let trusted_tx = self.holder_commitment.trust();
+				let counterparty_htlc_sig = self.holder_commitment.counterparty_htlc_sigs[*htlc_idx];
+				htlc_tx = Some(trusted_tx
+					.get_signed_htlc_tx(&self.channel_transaction_parameters.as_holder_broadcastable(), *htlc_idx, &counterparty_htlc_sig, htlc_sig, preimage));
 			}
 		}
-		if self.prev_holder_commitment.is_some() {
+		// If the HTLC doesn't spend the current holder commitment, check if it spends the previous one
+		if htlc_tx.is_none() && self.prev_holder_commitment.is_some() {
 			let commitment_txid = self.prev_holder_commitment.as_ref().unwrap().trust().txid();
 			if commitment_txid == outp.txid {
 				self.sign_prev_holder_htlcs();