From 55f8d792a93120ed63412253e0ee4761c515b9a3 Mon Sep 17 00:00:00 2001 From: Antoine Riard Date: Tue, 24 Mar 2020 14:47:37 -0400 Subject: [PATCH] Build witness_script for remote htlc transactions inside OnchainTxHandler By moving script generation inside OnchainTxHandler, we may dry-up further ChannelMonitor in next commits Comment MINIMALIF rule --- lightning/src/ln/channelmonitor.rs | 26 ++++++++++--------- lightning/src/ln/onchaintx.rs | 40 ++++++++++++++++++++---------- 2 files changed, 41 insertions(+), 25 deletions(-) diff --git a/lightning/src/ln/channelmonitor.rs b/lightning/src/ln/channelmonitor.rs index fc1c5e826..d35dbdab9 100644 --- a/lightning/src/ln/channelmonitor.rs +++ b/lightning/src/ln/channelmonitor.rs @@ -430,7 +430,7 @@ pub(crate) enum InputMaterial { amount: u64, }, RemoteHTLC { - witness_script: Script, + per_commitment_point: PublicKey, key: SecretKey, preimage: Option, amount: u64, @@ -455,9 +455,9 @@ impl Writeable for InputMaterial { input_descriptor.write(writer)?; writer.write_all(&byte_utils::be64_to_array(*amount))?; }, - &InputMaterial::RemoteHTLC { ref witness_script, ref key, ref preimage, ref amount, ref locktime } => { + &InputMaterial::RemoteHTLC { ref per_commitment_point, ref key, ref preimage, ref amount, ref locktime } => { writer.write_all(&[1; 1])?; - witness_script.write(writer)?; + per_commitment_point.write(writer)?; key.write(writer)?; preimage.write(writer)?; writer.write_all(&byte_utils::be64_to_array(*amount))?; @@ -493,13 +493,13 @@ impl Readable for InputMaterial { } }, 1 => { - let witness_script = Readable::read(reader)?; + let per_commitment_point = Readable::read(reader)?; let key = Readable::read(reader)?; let preimage = Readable::read(reader)?; let amount = Readable::read(reader)?; let locktime = Readable::read(reader)?; InputMaterial::RemoteHTLC { - witness_script, + per_commitment_point, key, preimage, amount, @@ -1556,24 +1556,26 @@ impl ChannelMonitor { if revocation_points.0 == commitment_number + 1 { Some(point) } else { None } } else { None }; if let Some(revocation_point) = revocation_point_option { - let revocation_pubkey = ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, revocation_point, &self.keys.pubkeys().revocation_basepoint)); - let b_htlc_key = ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, revocation_point, &self.keys.pubkeys().htlc_basepoint)); let htlc_privkey = ignore_error!(chan_utils::derive_private_key(&self.secp_ctx, revocation_point, &self.keys.htlc_base_key())); - let a_htlc_key = ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, revocation_point, &self.their_htlc_base_key)); + + self.remote_payment_script = { + // Note that the Network here is ignored as we immediately drop the address for the + // script_pubkey version + let payment_hash160 = WPubkeyHash::hash(&PublicKey::from_secret_key(&self.secp_ctx, &self.keys.payment_key()).serialize()); + Builder::new().push_opcode(opcodes::all::OP_PUSHBYTES_0).push_slice(&payment_hash160[..]).into_script() + }; // Then, try to find htlc outputs for (_, &(ref htlc, _)) in per_commitment_data.iter().enumerate() { if let Some(transaction_output_index) = htlc.transaction_output_index { - let expected_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&htlc, &a_htlc_key, &b_htlc_key, &revocation_pubkey); if transaction_output_index as usize >= tx.output.len() || - tx.output[transaction_output_index as usize].value != htlc.amount_msat / 1000 || - tx.output[transaction_output_index as usize].script_pubkey != expected_script.to_v0_p2wsh() { + tx.output[transaction_output_index as usize].value != htlc.amount_msat / 1000 { return (claimable_outpoints, (commitment_txid, watch_outputs)); // Corrupted per_commitment_data, fuck this user } let preimage = if htlc.offered { if let Some(p) = self.payment_preimages.get(&htlc.payment_hash) { Some(*p) } else { None } } else { None }; let aggregable = if !htlc.offered { false } else { true }; if preimage.is_some() || !htlc.offered { - let witness_data = InputMaterial::RemoteHTLC { witness_script: expected_script, key: htlc_privkey, preimage, amount: htlc.amount_msat / 1000, locktime: htlc.cltv_expiry }; + let witness_data = InputMaterial::RemoteHTLC { per_commitment_point: *revocation_point, key: htlc_privkey, preimage, amount: htlc.amount_msat / 1000, locktime: htlc.cltv_expiry }; claimable_outpoints.push(ClaimRequest { absolute_timelock: htlc.cltv_expiry, aggregable, outpoint: BitcoinOutPoint { txid: commitment_txid, vout: transaction_output_index }, witness_data }); } } diff --git a/lightning/src/ln/onchaintx.rs b/lightning/src/ln/onchaintx.rs index cb06fcbae..aee25ef6d 100644 --- a/lightning/src/ln/onchaintx.rs +++ b/lightning/src/ln/onchaintx.rs @@ -673,20 +673,34 @@ impl OnchainTxHandler { log_trace!(self, "Going to broadcast Penalty Transaction {} claiming revoked {} output {} from {} with new feerate {}...", bumped_tx.txid(), if *input_descriptor == InputDescriptors::RevokedOutput { "to_local" } else if *input_descriptor == InputDescriptors::RevokedOfferedHTLC { "offered" } else if *input_descriptor == InputDescriptors::RevokedReceivedHTLC { "received" } else { "" }, outp.vout, outp.txid, new_feerate); } }, - &InputMaterial::RemoteHTLC { ref witness_script, ref key, ref preimage, ref amount, ref locktime } => { - if !preimage.is_some() { bumped_tx.lock_time = *locktime }; // Right now we don't aggregate time-locked transaction, if we do we should set lock_time before to avoid breaking hash computation - let sighash_parts = bip143::SighashComponents::new(&bumped_tx); - let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]); - let sig = self.secp_ctx.sign(&sighash, &key); - 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.clone().0.to_vec()); - } else { - bumped_tx.input[i].witness.push(vec![]); + &InputMaterial::RemoteHTLC { ref per_commitment_point, ref key, ref preimage, ref amount, ref locktime } => { + if let Ok(chan_keys) = TxCreationKeys::new(&self.secp_ctx, &per_commitment_point, &self.remote_tx_cache.remote_delayed_payment_base_key, &self.remote_tx_cache.remote_htlc_base_key, &self.key_storage.pubkeys().revocation_basepoint, &self.key_storage.pubkeys().htlc_basepoint) { + let mut this_htlc = None; + if let Some(htlcs) = self.remote_tx_cache.per_htlc.get(&outp.txid) { + for htlc in htlcs { + if htlc.transaction_output_index.unwrap() == outp.vout { + this_htlc = Some(htlc); + } + } + } + if this_htlc.is_none() { return None; } + let witness_script = chan_utils::get_htlc_redeemscript_with_explicit_keys(&this_htlc.unwrap(), &chan_keys.a_htlc_key, &chan_keys.b_htlc_key, &chan_keys.revocation_key); + + if !preimage.is_some() { bumped_tx.lock_time = *locktime }; // Right now we don't aggregate time-locked transaction, if we do we should set lock_time before to avoid breaking hash computation + let sighash_parts = bip143::SighashComponents::new(&bumped_tx); + let sighash = hash_to_message!(&sighash_parts.sighash_all(&bumped_tx.input[i], &witness_script, *amount)[..]); + let sig = self.secp_ctx.sign(&sighash, &key); + 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.clone().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!(self, "Going to broadcast Claim Transaction {} claiming remote {} htlc output {} from {} with new feerate {}...", bumped_tx.txid(), if preimage.is_some() { "offered" } else { "received" }, outp.vout, outp.txid, new_feerate); } - bumped_tx.input[i].witness.push(witness_script.clone().into_bytes()); - log_trace!(self, "Going to broadcast Claim Transaction {} claiming remote {} htlc output {} from {} with new feerate {}...", bumped_tx.txid(), if preimage.is_some() { "offered" } else { "received" }, outp.vout, outp.txid, new_feerate); }, _ => unreachable!() } -- 2.39.5