From fb9ad5686ef2ad3f9ef06ad19b9ef1c8b60f8c1f Mon Sep 17 00:00:00 2001 From: Valentine Wallace Date: Sat, 12 Aug 2023 20:27:35 -0400 Subject: [PATCH] Document and test 0-len channel update onion error case --- lightning/src/ln/onion_route_tests.rs | 24 ++++++++++++++++++++++++ lightning/src/ln/onion_utils.rs | 2 ++ 2 files changed, 26 insertions(+) diff --git a/lightning/src/ln/onion_route_tests.rs b/lightning/src/ln/onion_route_tests.rs index 8550532c6..785c11304 100644 --- a/lightning/src/ln/onion_route_tests.rs +++ b/lightning/src/ln/onion_route_tests.rs @@ -645,6 +645,30 @@ fn test_onion_failure() { }, || nodes[2].node.fail_htlc_backwards(&payment_hash), false, None, Some(NetworkUpdate::NodeFailure { node_id: route.paths[0].hops[1].pubkey, is_permanent: true }), Some(channels[1].0.contents.short_channel_id)); + run_onion_failure_test_with_fail_intercept("0-length channel update in UPDATE onion failure", 200, &nodes, + &route, &payment_hash, &payment_secret, |_msg| {}, |msg| { + let session_priv = SecretKey::from_slice(&[3; 32]).unwrap(); + let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap(); + let mut decoded_err_packet = msgs::DecodedOnionErrorPacket { + failuremsg: vec![ + 0x10, 0x7, // UPDATE|7 + 0x0, 0x0 // 0-len channel update + ], + pad: vec![0; 255 - 4 /* 4-byte error message */], + hmac: [0; 32], + }; + let um = onion_utils::gen_um_from_shared_secret(&onion_keys[1].shared_secret.as_ref()); + let mut hmac = HmacEngine::::new(&um); + hmac.input(&decoded_err_packet.encode()[32..]); + decoded_err_packet.hmac = Hmac::from_engine(hmac).into_inner(); + msg.reason = onion_utils::encrypt_failure_packet( + &onion_keys[1].shared_secret.as_ref(), &decoded_err_packet.encode()[..]) + }, || nodes[2].node.fail_htlc_backwards(&payment_hash), true, Some(0x1000|7), + Some(NetworkUpdate::ChannelFailure { + short_channel_id: channels[1].0.contents.short_channel_id, + is_permanent: false, + }), + Some(channels[1].0.contents.short_channel_id)); } #[test] diff --git a/lightning/src/ln/onion_utils.rs b/lightning/src/ln/onion_utils.rs index 688a9c961..64a1e3fa3 100644 --- a/lightning/src/ln/onion_utils.rs +++ b/lightning/src/ln/onion_utils.rs @@ -579,6 +579,8 @@ where L::Target: Logger { msg: chan_update, }) } else { + // The node in question intentionally encoded a 0-length channel update. This is + // likely due to https://github.com/ElementsProject/lightning/issues/6200. network_update = Some(NetworkUpdate::ChannelFailure { short_channel_id: route_hop.short_channel_id, is_permanent: false, -- 2.39.5