From: Matt Corallo <git@bluematt.me>
Date: Thu, 17 Sep 2020 16:14:05 +0000 (-0400)
Subject: Demo double-spend-creation
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=refs%2Fheads%2F2020-09-demo-doublespend;hp=d735085cec8b119d8d702d833535d3140909d5d0;p=rust-lightning

Demo double-spend-creation
---

diff --git a/lightning/src/chain/chaininterface.rs b/lightning/src/chain/chaininterface.rs
index 295c337e2..bbef5ec72 100644
--- a/lightning/src/chain/chaininterface.rs
+++ b/lightning/src/chain/chaininterface.rs
@@ -380,9 +380,10 @@ impl ChainWatchInterface for ChainWatchInterfaceUtil {
 		{
 			let watched = self.watched.lock().unwrap();
 			for (index, transaction) in block.txdata.iter().enumerate() {
-				if self.does_match_tx_unguarded(transaction, &watched) {
+				// Note, while some clients filter, we can't rely on all clients filtering!
+				//if self.does_match_tx_unguarded(transaction, &watched) {
 					matched_index.push(index);
-				}
+				//}
 			}
 		}
 		matched_index
diff --git a/lightning/src/ln/functional_tests.rs b/lightning/src/ln/functional_tests.rs
index a94003c48..6703b1e2e 100644
--- a/lightning/src/ln/functional_tests.rs
+++ b/lightning/src/ln/functional_tests.rs
@@ -5037,9 +5037,16 @@ fn test_static_spendable_outputs_justice_tx_revoked_htlc_timeout_tx() {
 	check_added_monitors!(nodes[1], 1);
 
 	let node_txn = nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap();
-	assert_eq!(node_txn.len(), 4); // ChannelMonitor: justice tx on revoked commitment, justice tx on revoked HTLC-timeout, adjusted justice tx, ChannelManager: local commitment tx
-	assert_eq!(node_txn[0].input.len(), 2);
-	check_spends!(node_txn[0], revoked_local_txn[0]);
+	assert_eq!(node_txn.len(), 3); // ChannelMonitor: justice tx on revoked commitment, justice tx on revoked HTLC-timeout, adjusted justice tx, ChannelManager: local commitment tx
+
+	// node_txn[0] fully spends revoked_local_txn[0].
+	assert_eq!(node_txn[0].input.len(), 3);
+	assert_eq!(revoked_local_txn[0].output.len(), 2);
+	// node_txn[0] tries to spend both revoked_local_txn[0] and revoked_htlc_txn[0], but
+	// revoked_htlc_txn[0] spends revoked_local_txn[0] (ie this is a double-spend)!
+	check_spends!(node_txn[0], revoked_local_txn[0], revoked_htlc_txn[0]);
+	check_spends!(revoked_htlc_txn[0], revoked_local_txn[0]);
+
 	check_spends!(node_txn[1], chan_1.3);
 	assert_eq!(node_txn[2].input.len(), 1);
 	check_spends!(node_txn[2], revoked_htlc_txn[0]);