From: Matt Corallo Date: Thu, 29 Jul 2021 19:49:09 +0000 (+0000) Subject: Fix to_remote SpendableOutputs generation in rare reorg cases X-Git-Tag: v0.0.100~11^2 X-Git-Url: http://git.bitcoin.ninja/?a=commitdiff_plain;h=refs%2Fheads%2F2021-07-to-remote-reorg;p=rust-lightning Fix to_remote SpendableOutputs generation in rare reorg cases If we first see a local commitment transaction, and then a reorg causes the confirmed channel close transaction to instead be a remote commitment transaction, we would fail a spurious `if else` check, resulting in us not generating the correct `SpendableOutput` event for the to_remote output now confirmed on chain. This resolves the incorrect logic and adds a regression test. --- diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs index a8ec8ee97..525718c71 100644 --- a/lightning/src/chain/channelmonitor.rs +++ b/lightning/src/chain/channelmonitor.rs @@ -2451,7 +2451,8 @@ impl ChannelMonitorImpl { output: outp.clone(), }); break; - } else if let Some(ref broadcasted_holder_revokable_script) = self.broadcasted_holder_revokable_script { + } + if let Some(ref broadcasted_holder_revokable_script) = self.broadcasted_holder_revokable_script { if broadcasted_holder_revokable_script.0 == outp.script_pubkey { spendable_output = Some(SpendableOutputDescriptor::DelayedPaymentOutput(DelayedPaymentOutputDescriptor { outpoint: OutPoint { txid: tx.txid(), index: i as u16 }, @@ -2464,7 +2465,8 @@ impl ChannelMonitorImpl { })); break; } - } else if self.counterparty_payment_script == outp.script_pubkey { + } + if self.counterparty_payment_script == outp.script_pubkey { spendable_output = Some(SpendableOutputDescriptor::StaticPaymentOutput(StaticPaymentOutputDescriptor { outpoint: OutPoint { txid: tx.txid(), index: i as u16 }, output: outp.clone(), @@ -2472,11 +2474,13 @@ impl ChannelMonitorImpl { channel_value_satoshis: self.channel_value_satoshis, })); break; - } else if outp.script_pubkey == self.shutdown_script { + } + if outp.script_pubkey == self.shutdown_script { spendable_output = Some(SpendableOutputDescriptor::StaticOutput { outpoint: OutPoint { txid: tx.txid(), index: i as u16 }, output: outp.clone(), }); + break; } } if let Some(spendable_output) = spendable_output { diff --git a/lightning/src/ln/reorg_tests.rs b/lightning/src/ln/reorg_tests.rs index 9946cc24a..7845c089c 100644 --- a/lightning/src/ln/reorg_tests.rs +++ b/lightning/src/ln/reorg_tests.rs @@ -10,6 +10,7 @@ //! Further functional tests which test blockchain reorganizations. use chain::channelmonitor::{ANTI_REORG_DELAY, ChannelMonitor}; +use chain::transaction::OutPoint; use chain::{Confirm, Watch}; use ln::channelmanager::{ChannelManager, ChannelManagerReadArgs}; use ln::features::InitFeatures; @@ -20,7 +21,10 @@ use util::test_utils; use util::ser::{ReadableArgs, Writeable}; use bitcoin::blockdata::block::{Block, BlockHeader}; +use bitcoin::blockdata::script::Builder; +use bitcoin::blockdata::opcodes; use bitcoin::hash_types::BlockHash; +use bitcoin::secp256k1::Secp256k1; use prelude::*; use core::mem; @@ -427,3 +431,112 @@ fn test_set_outpoints_partial_claiming() { node_txn.clear(); } } + +fn do_test_to_remote_after_local_detection(style: ConnectStyle) { + // In previous code, detection of to_remote outputs in a counterparty commitment transaction + // was dependent on whether a local commitment transaction had been seen on-chain previously. + // This resulted in some edge cases around not being able to generate a SpendableOutput event + // after a reorg. + // + // Here, we test this by first confirming one set of commitment transactions, then + // disconnecting them and reconnecting another. We then confirm them and check that the correct + // SpendableOutput event is generated. + 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, &[None, None]); + let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs); + + *nodes[0].connect_style.borrow_mut() = style; + *nodes[1].connect_style.borrow_mut() = style; + + let (_, _, chan_id, funding_tx) = + create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 100_000_000, InitFeatures::known(), InitFeatures::known()); + let funding_outpoint = OutPoint { txid: funding_tx.txid(), index: 0 }; + assert_eq!(funding_outpoint.to_channel_id(), chan_id); + + let remote_txn_a = get_local_commitment_txn!(nodes[0], chan_id); + let remote_txn_b = get_local_commitment_txn!(nodes[1], chan_id); + + mine_transaction(&nodes[0], &remote_txn_a[0]); + mine_transaction(&nodes[1], &remote_txn_a[0]); + + assert!(nodes[0].node.list_channels().is_empty()); + check_closed_broadcast!(nodes[0], true); + check_added_monitors!(nodes[0], 1); + assert!(nodes[1].node.list_channels().is_empty()); + check_closed_broadcast!(nodes[1], true); + check_added_monitors!(nodes[1], 1); + + // Drop transactions broadcasted in response to the first commitment transaction (we have good + // test coverage of these things already elsewhere). + assert_eq!(nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0).len(), 1); + assert_eq!(nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0).len(), 1); + + assert!(nodes[0].chain_monitor.chain_monitor.get_and_clear_pending_events().is_empty()); + assert!(nodes[1].chain_monitor.chain_monitor.get_and_clear_pending_events().is_empty()); + + disconnect_blocks(&nodes[0], 1); + disconnect_blocks(&nodes[1], 1); + + assert!(nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().is_empty()); + assert!(nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().is_empty()); + assert!(nodes[0].chain_monitor.chain_monitor.get_and_clear_pending_events().is_empty()); + assert!(nodes[1].chain_monitor.chain_monitor.get_and_clear_pending_events().is_empty()); + + connect_blocks(&nodes[0], ANTI_REORG_DELAY - 1); + connect_blocks(&nodes[1], ANTI_REORG_DELAY - 1); + + assert!(nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().is_empty()); + assert!(nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().is_empty()); + assert!(nodes[0].chain_monitor.chain_monitor.get_and_clear_pending_events().is_empty()); + assert!(nodes[1].chain_monitor.chain_monitor.get_and_clear_pending_events().is_empty()); + + mine_transaction(&nodes[0], &remote_txn_b[0]); + mine_transaction(&nodes[1], &remote_txn_b[0]); + + assert!(nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().is_empty()); + assert!(nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().is_empty()); + assert!(nodes[0].chain_monitor.chain_monitor.get_and_clear_pending_events().is_empty()); + assert!(nodes[1].chain_monitor.chain_monitor.get_and_clear_pending_events().is_empty()); + + connect_blocks(&nodes[0], ANTI_REORG_DELAY - 1); + connect_blocks(&nodes[1], ANTI_REORG_DELAY - 1); + + let mut node_a_spendable = nodes[0].chain_monitor.chain_monitor.get_and_clear_pending_events(); + assert_eq!(node_a_spendable.len(), 1); + if let Event::SpendableOutputs { outputs } = node_a_spendable.pop().unwrap() { + assert_eq!(outputs.len(), 1); + let spend_tx = nodes[0].keys_manager.backing.spend_spendable_outputs(&[&outputs[0]], Vec::new(), + Builder::new().push_opcode(opcodes::all::OP_RETURN).into_script(), 253, &Secp256k1::new()).unwrap(); + check_spends!(spend_tx, remote_txn_b[0]); + } + + // nodes[1] is waiting for the to_self_delay to expire, which is many more than + // ANTI_REORG_DELAY. Instead, walk it back and confirm the original remote_txn_a commitment + // again and check that nodes[1] generates a similar spendable output. + // Technically a reorg of ANTI_REORG_DELAY violates our assumptions, so this is undefined by + // our API spec, but we currently handle this correctly and there's little reason we shouldn't + // in the future. + assert!(nodes[1].chain_monitor.chain_monitor.get_and_clear_pending_events().is_empty()); + disconnect_blocks(&nodes[1], ANTI_REORG_DELAY); + mine_transaction(&nodes[1], &remote_txn_a[0]); + connect_blocks(&nodes[1], ANTI_REORG_DELAY - 1); + + let mut node_b_spendable = nodes[1].chain_monitor.chain_monitor.get_and_clear_pending_events(); + assert_eq!(node_b_spendable.len(), 1); + if let Event::SpendableOutputs { outputs } = node_b_spendable.pop().unwrap() { + assert_eq!(outputs.len(), 1); + let spend_tx = nodes[1].keys_manager.backing.spend_spendable_outputs(&[&outputs[0]], Vec::new(), + Builder::new().push_opcode(opcodes::all::OP_RETURN).into_script(), 253, &Secp256k1::new()).unwrap(); + check_spends!(spend_tx, remote_txn_a[0]); + } +} + +#[test] +fn test_to_remote_after_local_detection() { + do_test_to_remote_after_local_detection(ConnectStyle::BestBlockFirst); + do_test_to_remote_after_local_detection(ConnectStyle::BestBlockFirstSkippingBlocks); + do_test_to_remote_after_local_detection(ConnectStyle::TransactionsFirst); + do_test_to_remote_after_local_detection(ConnectStyle::TransactionsFirstSkippingBlocks); + do_test_to_remote_after_local_detection(ConnectStyle::FullBlockViaListen); +}