Correctly fail back downstream-failed blinded HTLCs as intro

diff --git a/lightning/src/ln/blinded_payment_tests.rs b/lightning/src/ln/blinded_payment_tests.rs
index c0756782afa418f2e232132b86e9f8caf1798e87..2eacdc839d0d31c21991642cb7e1bc9f759540a2 100644 (file)
--- a/lightning/src/ln/blinded_payment_tests.rs
+++ b/lightning/src/ln/blinded_payment_tests.rs
@@ -235,3 +235,60 @@ fn do_forward_checks_failure(check: ForwardCheckFail) {
        expect_payment_failed_conditions(&nodes[0], payment_hash, false,
                PaymentFailedConditions::new().expected_htlc_error_data(INVALID_ONION_BLINDING, &[0; 32]));
 }
+
+#[test]
+fn failed_backwards_to_intro_node() {
+       // Ensure the intro node will error backwards properly even if the downstream node did not blind
+       // their error.
+       let chanmon_cfgs = create_chanmon_cfgs(3);
+       let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
+       let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
+       let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);
+       create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0);
+       let chan_upd_1_2 = create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 1_000_000, 0).0.contents;
+
+       let amt_msat = 5000;
+       let (_, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[2], Some(amt_msat), None);
+       let route_params = get_blinded_route_parameters(amt_msat, payment_secret,
+               nodes.iter().skip(1).map(|n| n.node.get_our_node_id()).collect(), &[&chan_upd_1_2],
+               &chanmon_cfgs[2].keys_manager);
+
+       nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params, Retry::Attempts(0)).unwrap();
+       check_added_monitors(&nodes[0], 1);
+
+       let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+       assert_eq!(events.len(), 1);
+       let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
+       let mut payment_event = SendEvent::from_event(ev);
+
+       nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
+       check_added_monitors!(nodes[1], 0);
+       do_commitment_signed_dance(&nodes[1], &nodes[0], &payment_event.commitment_msg, false, false);
+       expect_pending_htlcs_forwardable!(nodes[1]);
+       check_added_monitors!(&nodes[1], 1);
+
+       let mut events = nodes[1].node.get_and_clear_pending_msg_events();
+       assert_eq!(events.len(), 1);
+       let ev = remove_first_msg_event_to_node(&nodes[2].node.get_our_node_id(), &mut events);
+       let mut payment_event = SendEvent::from_event(ev);
+
+       // Ensure the final node fails to handle the HTLC.
+       payment_event.msgs[0].onion_routing_packet.hop_data[0] ^= 1;
+       nodes[2].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &payment_event.msgs[0]);
+       check_added_monitors!(nodes[2], 0);
+       do_commitment_signed_dance(&nodes[2], &nodes[1], &payment_event.commitment_msg, true, true);
+       nodes[2].node.process_pending_htlc_forwards();
+
+       let mut updates = get_htlc_update_msgs!(nodes[2], nodes[1].node.get_our_node_id());
+       let mut update_malformed = &mut updates.update_fail_malformed_htlcs[0];
+       // Ensure the final hop does not correctly blind their error.
+       update_malformed.sha256_of_onion = [1; 32];
+       nodes[1].node.handle_update_fail_malformed_htlc(&nodes[2].node.get_our_node_id(), update_malformed);
+       do_commitment_signed_dance(&nodes[1], &nodes[2], &updates.commitment_signed, true, false);
+
+       let mut updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
+       nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &updates.update_fail_htlcs[0]);
+       do_commitment_signed_dance(&nodes[0], &nodes[1], &updates.commitment_signed, false, false);
+       expect_payment_failed_conditions(&nodes[0], payment_hash, false,
+               PaymentFailedConditions::new().expected_htlc_error_data(INVALID_ONION_BLINDING, &[0; 32]));
+}

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index aa44a63e590d0c60547bea8cc7156d6810f7d27b..4247d57cbb6ad199ba99842c8dae506ee08f2e25 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -5158,9 +5158,23 @@ where
                                        &self.pending_events, &self.logger)
                                { self.push_pending_forwards_ev(); }
                        },
-                       HTLCSource::PreviousHopData(HTLCPreviousHopData { ref short_channel_id, ref htlc_id, ref incoming_packet_shared_secret, ref phantom_shared_secret, ref outpoint, .. }) => {
-                               log_trace!(self.logger, "Failing HTLC with payment_hash {} backwards from us with {:?}", &payment_hash, onion_error);
-                               let err_packet = onion_error.get_encrypted_failure_packet(incoming_packet_shared_secret, phantom_shared_secret);
+                       HTLCSource::PreviousHopData(HTLCPreviousHopData {
+                               ref short_channel_id, ref htlc_id, ref incoming_packet_shared_secret,
+                               ref phantom_shared_secret, ref outpoint, ref blinded_failure, ..
+                       }) => {
+                               log_trace!(self.logger, "Failing {}HTLC with payment_hash {} backwards from us: {:?}",
+                                       if blinded_failure.is_some() { "blinded " } else { "" }, &payment_hash, onion_error);
+                               let err_packet = match blinded_failure {
+                                       Some(BlindedFailure::FromIntroductionNode) => {
+                                               let blinded_onion_error = HTLCFailReason::reason(INVALID_ONION_BLINDING, vec![0; 32]);
+                                               blinded_onion_error.get_encrypted_failure_packet(
+                                                       incoming_packet_shared_secret, phantom_shared_secret
+                                               )
+                                       },
+                                       None => {
+                                               onion_error.get_encrypted_failure_packet(incoming_packet_shared_secret, phantom_shared_secret)
+                                       }
+                               };
 
                                let mut push_forward_ev = false;
                                let mut forward_htlcs = self.forward_htlcs.lock().unwrap();