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Decrypt Trampoline onions
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In this commit, we start decrypting the inner onion we receive, and lay
some groundwork towards handling the subsequent routing or payment
receipt.
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@arik-so
arik-so committed Mar 5, 2025
1 parent edbb070 commit 05b142b
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Showing 5 changed files with 486 additions and 38 deletions.
144 changes: 144 additions & 0 deletions lightning/src/ln/blinded_payment_tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1755,3 +1755,147 @@ fn test_combined_trampoline_onion_creation_vectors() {
assert_eq!(htlc_msat, 150_156_000);
assert_eq!(htlc_cltv, 800_060);
}

#[test]
#[cfg(trampoline)]
fn test_trampoline_inbound_payment_decoding() {
let secp_ctx = Secp256k1::new();
let session_priv = secret_from_hex("0303030303030303030303030303030303030303030303030303030303030303");

let bob_secret = secret_from_hex("4242424242424242424242424242424242424242424242424242424242424242");
let bob_node_id = PublicKey::from_secret_key(&secp_ctx, &bob_secret);
let _bob_unblinded_tlvs = bytes_from_hex("011a0000000000000000000000000000000000000000000000000000020800000000000006c10a0800240000009627100c06000b69e505dc0e00fd023103123456");
let carol_secret = secret_from_hex("4343434343434343434343434343434343434343434343434343434343434343");
let carol_node_id = PublicKey::from_secret_key(&secp_ctx, &carol_secret);
let _carol_unblinded_tlvs = bytes_from_hex("020800000000000004510821031b84c5567b126440995d3ed5aaba0565d71e1834604819ff9c17f5e9d5dd078f0a0800300000006401f40c06000b69c105dc0e00");
let dave_secret = secret_from_hex("4444444444444444444444444444444444444444444444444444444444444444");
let dave_node_id = PublicKey::from_secret_key(&secp_ctx, &dave_secret);
let _dave_unblinded_tlvs = bytes_from_hex("01230000000000000000000000000000000000000000000000000000000000000000000000020800000000000002310a060090000000fa0c06000b699105dc0e00");
let eve_secret = secret_from_hex("4545454545454545454545454545454545454545454545454545454545454545");
let _eve_node_id = PublicKey::from_secret_key(&secp_ctx, &eve_secret);
let _eve_unblinded_tlvs = bytes_from_hex("011a00000000000000000000000000000000000000000000000000000604deadbeef0c06000b690105dc0e0f020000000000000000000000000000fdffff0206c1");

let path = Path {
hops: vec![
// Bob
RouteHop {
pubkey: bob_node_id,
node_features: NodeFeatures::empty(),
short_channel_id: 0,
channel_features: ChannelFeatures::empty(),
fee_msat: 0,
cltv_expiry_delta: 0,
maybe_announced_channel: false,
},

// Carol
RouteHop {
pubkey: carol_node_id,
node_features: NodeFeatures::empty(),
short_channel_id: (572330 << 40) + (42 << 16) + 2821,
channel_features: ChannelFeatures::empty(),
fee_msat: 150_153_000,
cltv_expiry_delta: 0,
maybe_announced_channel: false,
},
],
blinded_tail: Some(BlindedTail {
trampoline_hops: vec![
// Carol's pubkey
TrampolineHop {
pubkey: carol_node_id,
node_features: Features::empty(),
fee_msat: 2_500,
cltv_expiry_delta: 24,
},
// Dave's pubkey (the intro node needs to be duplicated)
TrampolineHop {
pubkey: dave_node_id,
node_features: Features::empty(),
fee_msat: 150_500, // incorporate both base and proportional fee
cltv_expiry_delta: 36,
}
],
hops: vec![
// Dave's blinded node id
BlindedHop {
blinded_node_id: pubkey_from_hex("0295d40514096a8be54859e7dfe947b376eaafea8afe5cb4eb2c13ff857ed0b4be"),
encrypted_payload: bytes_from_hex("0ccf3c8a58deaa603f657ee2a5ed9d604eb5c8ca1e5f801989afa8f3ea6d789bbdde2c7e7a1ef9ca8c38d2c54760febad8446d3f273ddb537569ef56613846ccd3aba78a"),
},
// Eve's blinded node id
BlindedHop {
blinded_node_id: pubkey_from_hex("020e2dbadcc2005e859819ddebbe88a834ae8a6d2b049233c07335f15cd1dc5f22"),
encrypted_payload: bytes_from_hex("bcd747394fbd4d99588da075a623316e15a576df5bc785cccc7cd6ec7b398acce6faf520175f9ec920f2ef261cdb83dc28cc3a0eeb970107b3306489bf771ef5b1213bca811d345285405861d08a655b6c237fa247a8b4491beee20c878a60e9816492026d8feb9dafa84585b253978db6a0aa2945df5ef445c61e801fb82f43d5f00716baf9fc9b3de50bc22950a36bda8fc27bfb1242e5860c7e687438d4133e058770361a19b6c271a2a07788d34dccc27e39b9829b061a4d960eac4a2c2b0f4de506c24f9af3868c0aff6dda27281c"),
}
],
blinding_point: pubkey_from_hex("02988face71e92c345a068f740191fd8e53be14f0bb957ef730d3c5f76087b960e"),
excess_final_cltv_expiry_delta: 0,
final_value_msat: 150_000_000
})
};

let payment_secret = PaymentSecret(secret_from_hex("7494b65bc092b48a75465e43e29be807eb2cc535ce8aaba31012b8ff1ceac5da").secret_bytes());

let amt_msat = 150_000_001;
let cur_height = 800_001;
let recipient_onion_fields = RecipientOnionFields::secret_only(payment_secret);
let (bob_onion, _, _) = onion_utils::create_payment_onion(&secp_ctx, &path, &session_priv, amt_msat, &recipient_onion_fields, cur_height, &PaymentHash([0; 32]), &None, None, [0; 32]).unwrap();

struct TestEcdhSigner {
node_secret: SecretKey,
}
impl NodeSigner for TestEcdhSigner {
fn ecdh(
&self, _recipient: Recipient, other_key: &PublicKey, tweak: Option<&Scalar>,
) -> Result<SharedSecret, ()> {
let mut node_secret = self.node_secret.clone();
if let Some(tweak) = tweak {
node_secret = self.node_secret.mul_tweak(tweak).map_err(|_| ())?;
}
Ok(SharedSecret::new(other_key, &node_secret))
}
fn get_inbound_payment_key(&self) -> ExpandedKey { unreachable!() }
fn get_node_id(&self, _recipient: Recipient) -> Result<PublicKey, ()> { unreachable!() }
fn sign_invoice(
&self, _invoice: &RawBolt11Invoice, _recipient: Recipient,
) -> Result<RecoverableSignature, ()> { unreachable!() }
fn sign_bolt12_invoice(
&self, _invoice: &UnsignedBolt12Invoice,
) -> Result<schnorr::Signature, ()> { unreachable!() }
fn sign_gossip_message(&self, _msg: UnsignedGossipMessage) -> Result<Signature, ()> { unreachable!() }
}
let logger = test_utils::TestLogger::with_id("".to_owned());

let bob_update_add = update_add_msg(111_000, 747_501, None, bob_onion);
let bob_node_signer = TestEcdhSigner { node_secret: bob_secret };

let (bob_peeled_onion, next_packet_details_opt) = onion_payment::decode_incoming_update_add_htlc_onion(
&bob_update_add, &bob_node_signer, &logger, &secp_ctx
).unwrap_or_else(|_| panic!());

let (carol_packet_bytes, carol_hmac) = if let onion_utils::Hop::Forward {
next_hop_data: msgs::InboundOnionForwardPayload {..}, next_hop_hmac, new_packet_bytes, ..
} = bob_peeled_onion {
(new_packet_bytes, next_hop_hmac)
} else { panic!() };

let carol_packet_details = next_packet_details_opt.unwrap();
let carol_onion = msgs::OnionPacket {
version: 0,
public_key: carol_packet_details.next_packet_pubkey,
hop_data: carol_packet_bytes,
hmac: carol_hmac,
};
let carol_update_add = update_add_msg(carol_packet_details.outgoing_amt_msat, carol_packet_details.outgoing_cltv_value, None, carol_onion);

let carol_node_signer = TestEcdhSigner { node_secret: carol_secret };
let (carol_peeled_onion, _) = onion_payment::decode_incoming_update_add_htlc_onion(
&carol_update_add, &carol_node_signer, &logger, &secp_ctx
).unwrap_or_else(|_| panic!());

let _carol_trampoline_update_add = if let onion_utils::Hop::TrampolineForward { next_trampoline_hop_data, .. } = carol_peeled_onion {
assert_eq!(next_trampoline_hop_data.next_trampoline, dave_node_id);
} else {
panic!();
};
}
31 changes: 27 additions & 4 deletions lightning/src/ln/channelmanager.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -54,8 +54,6 @@ use crate::ln::channel_state::ChannelDetails;
use crate::types::features::{Bolt12InvoiceFeatures, ChannelFeatures, ChannelTypeFeatures, InitFeatures, NodeFeatures};
#[cfg(any(feature = "_test_utils", test))]
use crate::types::features::Bolt11InvoiceFeatures;
#[cfg(trampoline)]
use crate::routing::gossip::NodeId;
use crate::routing::router::{BlindedTail, InFlightHtlcs, Path, Payee, PaymentParameters, RouteParameters, RouteParametersConfig, Router, FixedRouter, Route};
use crate::ln::onion_payment::{check_incoming_htlc_cltv, create_recv_pending_htlc_info, create_fwd_pending_htlc_info, decode_incoming_update_add_htlc_onion, HopConnector, InboundHTLCErr, NextPacketDetails};
use crate::ln::msgs;
Expand Down Expand Up @@ -181,7 +179,7 @@ pub enum PendingHTLCRouting {
/// do with the HTLC.
onion_packet: msgs::TrampolineOnionPacket,
/// The node ID of the Trampoline node which we need to route this HTLC to.
node_id: NodeId,
node_id: PublicKey,
/// Set if this HTLC is being forwarded within a blinded path.
blinded: Option<BlindedForward>,
/// The absolute CLTV of the inbound HTLC
Expand Down Expand Up @@ -4477,11 +4475,36 @@ where
Err(InboundHTLCErr { err_code, err_data, msg }) => return_err!(msg, err_code, &err_data)
}
},
#[cfg(trampoline)]
onion_utils::Hop::TrampolineReceive { .. } | onion_utils::Hop::TrampolineBlindedReceive { .. } => {
// OUR PAYMENT!
let current_height: u32 = self.best_block.read().unwrap().height;
match create_recv_pending_htlc_info(decoded_hop, shared_secret, msg.payment_hash,
msg.amount_msat, msg.cltv_expiry, None, allow_underpay, msg.skimmed_fee_msat,
current_height)
{
Ok(info) => {
// Note that we could obviously respond immediately with an update_fulfill_htlc
// message, however that would leak that we are the recipient of this payment, so
// instead we stay symmetric with the forwarding case, only responding (after a
// delay) once they've sent us a commitment_signed!
PendingHTLCStatus::Forward(info)
},
Err(InboundHTLCErr { err_code, err_data, msg }) => return_err!(msg, err_code, &err_data)
}
},
onion_utils::Hop::Forward { .. } | onion_utils::Hop::BlindedForward { .. } => {
match create_fwd_pending_htlc_info(msg, decoded_hop, shared_secret, next_packet_pubkey_opt) {
Ok(info) => PendingHTLCStatus::Forward(info),
Err(InboundHTLCErr { err_code, err_data, msg }) => return_err!(msg, err_code, &err_data)
}
},
#[cfg(trampoline)]
onion_utils::Hop::TrampolineForward { .. } | onion_utils::Hop::TrampolineBlindedForward { .. } => {
match create_fwd_pending_htlc_info(msg, decoded_hop, shared_secret, next_packet_pubkey_opt) {
Ok(info) => PendingHTLCStatus::Forward(info),
Err(InboundHTLCErr { err_code, err_data, msg }) => return_err!(msg, err_code, &err_data)
}
}
}
}
Expand Down Expand Up @@ -5893,7 +5916,7 @@ where
// of the onion.
failed_payment!(err_msg, err_code, sha256_of_onion.to_vec(), None);
},
Err(onion_utils::OnionDecodeErr::Relay { err_msg, err_code, shared_secret }) => {
Err(onion_utils::OnionDecodeErr::Relay { err_msg, err_code, shared_secret, .. }) => {
let phantom_shared_secret = shared_secret.secret_bytes();
failed_payment!(err_msg, err_code, Vec::new(), Some(phantom_shared_secret));
},
Expand Down
3 changes: 0 additions & 3 deletions lightning/src/ln/msgs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2127,7 +2127,6 @@ mod fuzzy_internal_msgs {
}

#[cfg(trampoline)]
#[cfg_attr(trampoline, allow(unused))]
pub struct InboundTrampolineForwardPayload {
pub next_trampoline: PublicKey,
/// The value, in msat, of the payment after this hop's fee is deducted.
Expand All @@ -2136,7 +2135,6 @@ mod fuzzy_internal_msgs {
}

#[cfg(trampoline)]
#[cfg_attr(trampoline, allow(unused))]
pub struct InboundTrampolineBlindedForwardPayload {
pub next_trampoline: PublicKey,
pub payment_relay: PaymentRelay,
Expand All @@ -2147,7 +2145,6 @@ mod fuzzy_internal_msgs {
}

#[cfg(trampoline)]
#[cfg_attr(trampoline, allow(unused))]
pub enum InboundTrampolinePayload {
Forward(InboundTrampolineForwardPayload),
BlindedForward(InboundTrampolineBlindedForwardPayload),
Expand Down
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