Merge pull request #2277 from valentinewallace/2023-05-fix-big-oms

Fix large onion message packet generation

Author: valentinewallace

lightning/src/ln/onion_utils.rs

@@ -324,7 +324,8 @@ fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
 		chacha.process_in_place(packet_data);
 
 		if i == 0 {
-			packet_data[ONION_DATA_LEN - filler.len()..ONION_DATA_LEN].copy_from_slice(&filler[..]);
+			let onion_data_len = packet_data.len();
+			packet_data[onion_data_len - filler.len()..onion_data_len].copy_from_slice(&filler[..]);
 		}
 
 		let mut hmac = HmacEngine::<Sha256>::new(&keys.mu);

lightning/src/onion_message/functional_tests.rs

@@ -20,13 +20,15 @@ use crate::util::test_utils;
 use bitcoin::network::constants::Network;
 use bitcoin::secp256k1::{PublicKey, Secp256k1};
 
+use core::sync::atomic::{AtomicU16, Ordering};
 use crate::io;
 use crate::io_extras::read_to_end;
 use crate::sync::Arc;
 
 struct MessengerNode {
 	keys_manager: Arc<test_utils::TestKeysInterface>,
 	messenger: OnionMessenger<Arc<test_utils::TestKeysInterface>, Arc<test_utils::TestKeysInterface>, Arc<test_utils::TestLogger>, Arc<TestCustomMessageHandler>>,
+	custom_message_handler: Arc<TestCustomMessageHandler>,
 	logger: Arc<test_utils::TestLogger>,
 }
 
@@ -54,11 +56,32 @@ impl Writeable for TestCustomMessage {
 	}
 }
 
-struct TestCustomMessageHandler {}
+struct TestCustomMessageHandler {
+	num_messages_expected: AtomicU16,
+}
+
+impl TestCustomMessageHandler {
+	fn new() -> Self {
+		Self { num_messages_expected: AtomicU16::new(0) }
+	}
+}
+
+impl Drop for TestCustomMessageHandler {
+	fn drop(&mut self) {
+		#[cfg(feature = "std")] {
+			if std::thread::panicking() {
+				return;
+			}
+		}
+		assert_eq!(self.num_messages_expected.load(Ordering::SeqCst), 0);
+	}
+}
 
 impl CustomOnionMessageHandler for TestCustomMessageHandler {
 	type CustomMessage = TestCustomMessage;
-	fn handle_custom_message(&self, _msg: Self::CustomMessage) {}
+	fn handle_custom_message(&self, _msg: Self::CustomMessage) {
+		self.num_messages_expected.fetch_sub(1, Ordering::SeqCst);
+	}
 	fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, DecodeError> where Self: Sized {
 		if message_type == CUSTOM_MESSAGE_TYPE {
 			let buf = read_to_end(buffer)?;
@@ -75,9 +98,11 @@ fn create_nodes(num_messengers: u8) -> Vec<MessengerNode> {
 		let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
 		let seed = [i as u8; 32];
 		let keys_manager = Arc::new(test_utils::TestKeysInterface::new(&seed, Network::Testnet));
+		let custom_message_handler = Arc::new(TestCustomMessageHandler::new());
 		nodes.push(MessengerNode {
 			keys_manager: keys_manager.clone(),
-			messenger: OnionMessenger::new(keys_manager.clone(), keys_manager.clone(), logger.clone(), Arc::new(TestCustomMessageHandler {})),
+			messenger: OnionMessenger::new(keys_manager.clone(), keys_manager.clone(), logger.clone(), custom_message_handler.clone()),
+			custom_message_handler,
 			logger,
 		});
 	}
@@ -92,22 +117,17 @@ fn create_nodes(num_messengers: u8) -> Vec<MessengerNode> {
 	nodes
 }
 
-fn pass_along_path(path: &Vec<MessengerNode>, expected_path_id: Option<[u8; 32]>) {
+fn pass_along_path(path: &Vec<MessengerNode>) {
+	path[path.len() - 1].custom_message_handler.num_messages_expected.fetch_add(1, Ordering::SeqCst);
 	let mut prev_node = &path[0];
-	let num_nodes = path.len();
-	for (idx, node) in path.into_iter().skip(1).enumerate() {
+	for node in path.into_iter().skip(1) {
 		let events = prev_node.messenger.release_pending_msgs();
 		let onion_msg =  {
 			let msgs = events.get(&node.get_node_pk()).unwrap();
 			assert_eq!(msgs.len(), 1);
 			msgs[0].clone()
 		};
 		node.messenger.handle_onion_message(&prev_node.get_node_pk(), &onion_msg);
-		if idx == num_nodes - 1 {
-			node.logger.assert_log_contains(
-				"lightning::onion_message::messenger",
-				&format!("Received an onion message with path_id: {:02x?}", expected_path_id), 1);
-		}
 		prev_node = node;
 	}
 }
@@ -118,7 +138,7 @@ fn one_hop() {
 	let test_msg = OnionMessageContents::Custom(TestCustomMessage {});
 
 	nodes[0].messenger.send_onion_message(&[], Destination::Node(nodes[1].get_node_pk()), test_msg, None).unwrap();
-	pass_along_path(&nodes, None);
+	pass_along_path(&nodes);
 }
 
 #[test]
@@ -127,7 +147,7 @@ fn two_unblinded_hops() {
 	let test_msg = OnionMessageContents::Custom(TestCustomMessage {});
 
 	nodes[0].messenger.send_onion_message(&[nodes[1].get_node_pk()], Destination::Node(nodes[2].get_node_pk()), test_msg, None).unwrap();
-	pass_along_path(&nodes, None);
+	pass_along_path(&nodes);
 }
 
 #[test]
@@ -139,7 +159,7 @@ fn two_unblinded_two_blinded() {
 	let blinded_path = BlindedPath::new_for_message(&[nodes[3].get_node_pk(), nodes[4].get_node_pk()], &*nodes[4].keys_manager, &secp_ctx).unwrap();
 
 	nodes[0].messenger.send_onion_message(&[nodes[1].get_node_pk(), nodes[2].get_node_pk()], Destination::BlindedPath(blinded_path), test_msg, None).unwrap();
-	pass_along_path(&nodes, None);
+	pass_along_path(&nodes);
 }
 
 #[test]
@@ -151,7 +171,7 @@ fn three_blinded_hops() {
 	let blinded_path = BlindedPath::new_for_message(&[nodes[1].get_node_pk(), nodes[2].get_node_pk(), nodes[3].get_node_pk()], &*nodes[3].keys_manager, &secp_ctx).unwrap();
 
 	nodes[0].messenger.send_onion_message(&[], Destination::BlindedPath(blinded_path), test_msg, None).unwrap();
-	pass_along_path(&nodes, None);
+	pass_along_path(&nodes);
 }
 
 #[test]
@@ -177,13 +197,13 @@ fn we_are_intro_node() {
 	let blinded_path = BlindedPath::new_for_message(&[nodes[0].get_node_pk(), nodes[1].get_node_pk(), nodes[2].get_node_pk()], &*nodes[2].keys_manager, &secp_ctx).unwrap();
 
 	nodes[0].messenger.send_onion_message(&[], Destination::BlindedPath(blinded_path), OnionMessageContents::Custom(test_msg.clone()), None).unwrap();
-	pass_along_path(&nodes, None);
+	pass_along_path(&nodes);
 
 	// Try with a two-hop blinded path where we are the introduction node.
 	let blinded_path = BlindedPath::new_for_message(&[nodes[0].get_node_pk(), nodes[1].get_node_pk()], &*nodes[1].keys_manager, &secp_ctx).unwrap();
 	nodes[0].messenger.send_onion_message(&[], Destination::BlindedPath(blinded_path), OnionMessageContents::Custom(test_msg), None).unwrap();
 	nodes.remove(2);
-	pass_along_path(&nodes, None);
+	pass_along_path(&nodes);
 }
 
 #[test]
@@ -216,7 +236,7 @@ fn reply_path() {
 	// Destination::Node
 	let reply_path = BlindedPath::new_for_message(&[nodes[2].get_node_pk(), nodes[1].get_node_pk(), nodes[0].get_node_pk()], &*nodes[0].keys_manager, &secp_ctx).unwrap();
 	nodes[0].messenger.send_onion_message(&[nodes[1].get_node_pk(), nodes[2].get_node_pk()], Destination::Node(nodes[3].get_node_pk()), OnionMessageContents::Custom(test_msg.clone()), Some(reply_path)).unwrap();
-	pass_along_path(&nodes, None);
+	pass_along_path(&nodes);
 	// Make sure the last node successfully decoded the reply path.
 	nodes[3].logger.assert_log_contains(
 		"lightning::onion_message::messenger",
@@ -227,7 +247,7 @@ fn reply_path() {
 	let reply_path = BlindedPath::new_for_message(&[nodes[2].get_node_pk(), nodes[1].get_node_pk(), nodes[0].get_node_pk()], &*nodes[0].keys_manager, &secp_ctx).unwrap();
 
 	nodes[0].messenger.send_onion_message(&[], Destination::BlindedPath(blinded_path), OnionMessageContents::Custom(test_msg), Some(reply_path)).unwrap();
-	pass_along_path(&nodes, None);
+	pass_along_path(&nodes);
 	nodes[3].logger.assert_log_contains(
 		"lightning::onion_message::messenger",
 		&format!("Received an onion message with path_id None and a reply_path"), 2);
@@ -264,3 +284,20 @@ fn peer_buffer_full() {
 	let err = nodes[0].messenger.send_onion_message(&[], Destination::Node(nodes[1].get_node_pk()), OnionMessageContents::Custom(test_msg), None).unwrap_err();
 	assert_eq!(err, SendError::BufferFull);
 }
+
+#[test]
+fn many_hops() {
+	// Check we can send over a route with many hops. This will exercise our logic for onion messages
+	// of size [`crate::onion_message::packet::BIG_PACKET_HOP_DATA_LEN`].
+	let num_nodes: usize = 25;
+	let nodes = create_nodes(num_nodes as u8);
+	let test_msg = OnionMessageContents::Custom(TestCustomMessage {});
+
+	let mut intermediates = vec![];
+	for i in 1..(num_nodes-1) {
+		intermediates.push(nodes[i].get_node_pk());
+	}
+
+	nodes[0].messenger.send_onion_message(&intermediates, Destination::Node(nodes[num_nodes-1].get_node_pk()), test_msg, None).unwrap();
+	pass_along_path(&nodes);
+}

pending_changelog/big-om-error.txt

@@ -0,0 +1,4 @@
+## Bug Fixes
+
+* Fixed sending large onion messages, which previously would result in an HMAC error on the second
+	hop (#2277).