From 918f09c5291815bf4feaf0f754a5544e426bcfa8 Mon Sep 17 00:00:00 2001
From: Valentine Wallace <vwallace@protonmail.com>
Date: Fri, 15 Sep 2023 18:10:22 -0400
Subject: [PATCH] Test blinded forward failure to calculate outbound cltv
 expiry

Intro node failure only.
---
 lightning/src/ln/blinded_payment_tests.rs | 71 ++++++++++++++++++++++-
 1 file changed, 70 insertions(+), 1 deletion(-)

diff --git a/lightning/src/ln/blinded_payment_tests.rs b/lightning/src/ln/blinded_payment_tests.rs
index e8b6bfd67..56bf629ac 100644
--- a/lightning/src/ln/blinded_payment_tests.rs
+++ b/lightning/src/ln/blinded_payment_tests.rs
@@ -9,11 +9,14 @@
 
 use bitcoin::secp256k1::Secp256k1;
 use crate::blinded_path::BlindedPath;
-use crate::blinded_path::payment::{PaymentConstraints, ReceiveTlvs};
+use crate::blinded_path::payment::{ForwardNode, ForwardTlvs, PaymentConstraints, PaymentRelay, ReceiveTlvs};
 use crate::events::MessageSendEventsProvider;
 use crate::ln::channelmanager;
 use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
+use crate::ln::features::BlindedHopFeatures;
 use crate::ln::functional_test_utils::*;
+use crate::ln::msgs::ChannelMessageHandler;
+use crate::ln::onion_utils::INVALID_ONION_BLINDING;
 use crate::ln::outbound_payment::Retry;
 use crate::prelude::*;
 use crate::routing::router::{PaymentParameters, RouteParameters};
@@ -109,3 +112,69 @@ fn mpp_to_one_hop_blinded_path() {
 		Some(payment_secret), ev.clone(), true, None);
 	claim_payment_along_route(&nodes[0], expected_route, false, payment_preimage);
 }
+
+#[test]
+fn forward_checks_failure() {
+	// Ensure we'll fail backwards properly if a forwarding check fails on initial update_add
+	// receipt.
+	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 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 intermediate_nodes = vec![ForwardNode {
+		node_id: nodes[1].node.get_our_node_id(),
+		tlvs: ForwardTlvs {
+			short_channel_id: chan_upd_1_2.short_channel_id,
+			payment_relay: PaymentRelay {
+				cltv_expiry_delta: chan_upd_1_2.cltv_expiry_delta,
+				fee_proportional_millionths: chan_upd_1_2.fee_proportional_millionths,
+				fee_base_msat: chan_upd_1_2.fee_base_msat,
+			},
+			payment_constraints: PaymentConstraints {
+				max_cltv_expiry: u32::max_value(),
+				htlc_minimum_msat: chan_upd_1_2.htlc_minimum_msat,
+			},
+			features: BlindedHopFeatures::empty(),
+		},
+		htlc_maximum_msat: chan_upd_1_2.htlc_maximum_msat,
+	}];
+	let payee_tlvs = ReceiveTlvs {
+		payment_secret,
+		payment_constraints: PaymentConstraints {
+			max_cltv_expiry: u32::max_value(),
+			htlc_minimum_msat: chan_upd_1_2.htlc_minimum_msat,
+		},
+	};
+	let mut secp_ctx = Secp256k1::new();
+	let blinded_path = BlindedPath::new_for_payment(
+		&intermediate_nodes[..], nodes[2].node.get_our_node_id(), payee_tlvs,
+		chan_upd_1_2.htlc_maximum_msat, &chanmon_cfgs[2].keys_manager, &secp_ctx
+	).unwrap();
+
+	let route_params = RouteParameters::from_payment_params_and_value(
+		PaymentParameters::blinded(vec![blinded_path]), amt_msat);
+	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);
+
+	let mut update_add = &mut payment_event.msgs[0];
+	update_add.cltv_expiry = 10; // causes outbound CLTV expiry to underflow
+	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, true, true);
+
+	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]));
+}
-- 
2.39.5