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Reject unknown TLVs in blinded payment payloads #4546

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65 changes: 61 additions & 4 deletions lightning/src/blinded_path/payment.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -632,7 +632,7 @@ impl<'a> Writeable for BlindedPaymentTlvsRef<'a> {

impl Readable for BlindedPaymentTlvs {
fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
_init_and_read_tlv_stream!(r, {
_init_and_read_tlv_stream_with_custom_tlv_decode!(r, {
// Reasoning: Padding refers to filler data added to a packet to increase
// its size and obscure its actual length. Since padding contains no meaningful
// information, we can safely omit reading it here.
Expand All @@ -645,6 +645,14 @@ impl Readable for BlindedPaymentTlvs {
(65536, payment_secret, option),
(65537, payment_context, option),
(65539, is_dummy, option)
}, |typ: u64, _reader: &mut FixedLengthReader<_>| -> Result<bool, DecodeError> {
if typ == 1 {
return Ok(true);
}
if typ % 2 == 1 {
return Err(DecodeError::UnknownRequiredFeature);
}
Ok(false)
});

match (
Expand Down Expand Up @@ -685,14 +693,22 @@ impl Readable for BlindedPaymentTlvs {

impl Readable for BlindedTrampolineTlvs {
fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
_init_and_read_tlv_stream!(r, {
_init_and_read_tlv_stream_with_custom_tlv_decode!(r, {
(4, next_trampoline, option),
(8, next_blinding_override, option),
(10, payment_relay, option),
(12, payment_constraints, required),
(14, features, (option, encoding: (BlindedHopFeatures, WithoutLength))),
(65536, payment_secret, option),
(65537, payment_context, option),
}, |typ: u64, _reader: &mut FixedLengthReader<_>| -> Result<bool, DecodeError> {
if typ == 1 {
return Ok(true);
}
if typ % 2 == 1 {
return Err(DecodeError::UnknownRequiredFeature);
}
Ok(false)
});

if let Some(next_trampoline) = next_trampoline {
Expand Down Expand Up @@ -964,12 +980,15 @@ impl_writeable_tlv_based!(Bolt12RefundContext, {});
#[cfg(test)]
mod tests {
use crate::blinded_path::payment::{
Bolt12RefundContext, ForwardTlvs, PaymentConstraints, PaymentContext, PaymentForwardNode,
PaymentRelay, ReceiveTlvs,
BlindedPaymentTlvs, BlindedTrampolineTlvs, Bolt12RefundContext, ForwardTlvs,
PaymentConstraints, PaymentContext, PaymentForwardNode, PaymentRelay, ReceiveTlvs,
};
use crate::io::Cursor;
use crate::ln::functional_test_utils::TEST_FINAL_CLTV;
use crate::ln::msgs::DecodeError;
use crate::types::features::BlindedHopFeatures;
use crate::types::payment::PaymentSecret;
use crate::util::ser::{BigSize, Readable, Writeable};
use bitcoin::secp256k1::PublicKey;

#[test]
Expand Down Expand Up @@ -1237,4 +1256,42 @@ mod tests {
.unwrap();
assert_eq!(blinded_payinfo.htlc_maximum_msat, 3997);
}

#[test]
fn blinded_payment_tlvs_reject_unknown_odd_types() {
let receive_tlvs = ReceiveTlvs {
payment_secret: PaymentSecret([0; 32]),
payment_constraints: PaymentConstraints { max_cltv_expiry: 0, htlc_minimum_msat: 1 },
payment_context: PaymentContext::Bolt12Refund(Bolt12RefundContext {}),
};

let mut encoded = Vec::new();
receive_tlvs.write(&mut encoded).unwrap();
BigSize(65541).write(&mut encoded).unwrap();
BigSize(0).write(&mut encoded).unwrap();

assert!(matches!(
BlindedPaymentTlvs::read(&mut Cursor::new(&encoded)),
Err(DecodeError::UnknownRequiredFeature),
));
}

#[test]
fn blinded_trampoline_tlvs_reject_unknown_odd_types() {
let receive_tlvs = ReceiveTlvs {
payment_secret: PaymentSecret([0; 32]),
payment_constraints: PaymentConstraints { max_cltv_expiry: 0, htlc_minimum_msat: 1 },
payment_context: PaymentContext::Bolt12Refund(Bolt12RefundContext {}),
};

let mut encoded = Vec::new();
receive_tlvs.write(&mut encoded).unwrap();
BigSize(65541).write(&mut encoded).unwrap();
BigSize(0).write(&mut encoded).unwrap();

assert!(matches!(
BlindedTrampolineTlvs::read(&mut Cursor::new(&encoded)),
Err(DecodeError::UnknownRequiredFeature),
));
}
}
133 changes: 20 additions & 113 deletions lightning/src/ln/blinded_payment_tests.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1412,7 +1412,7 @@ fn custom_tlvs_to_blinded_path() {
let chan_upd = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0).0.contents;

let amt_msat = 5000;
let (payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[1], Some(amt_msat), None);
let (_payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[1], Some(amt_msat), None);
let payee_tlvs = ReceiveTlvs {
payment_secret,
payment_constraints: PaymentConstraints {
Expand Down Expand Up @@ -1448,12 +1448,23 @@ fn custom_tlvs_to_blinded_path() {
let path = &[&nodes[1]];
let args = PassAlongPathArgs::new(&nodes[0], path, amt_msat, payment_hash, ev)
.with_payment_secret(payment_secret)
.with_custom_tlvs(recipient_onion_fields.custom_tlvs.clone());
.with_custom_tlvs(recipient_onion_fields.custom_tlvs.clone())
.without_clearing_recipient_events()
.without_claimable_event();
do_pass_along_path(args);
claim_payment_along_route(
ClaimAlongRouteArgs::new(&nodes[0], &[&[&nodes[1]]], payment_preimage)
.with_custom_tlvs(recipient_onion_fields.custom_tlvs.clone())
check_added_monitors(&nodes[1], 1);

expect_htlc_handling_failed_destinations!(
nodes[1].node.get_and_clear_pending_events(),
&[HTLCHandlingFailureType::InvalidOnion]
);
let updates = get_htlc_update_msgs(&nodes[1], &nodes[0].node.get_our_node_id());
assert_eq!(updates.update_fail_htlcs.len(), 1);
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, true,
PaymentFailedConditions::new()
.expected_htlc_error_data(LocalHTLCFailureReason::InvalidOnionPayload, &[0; 0]));
}

#[test]
Expand Down Expand Up @@ -1718,116 +1729,12 @@ fn route_blinding_spec_test_vector() {
let bob_update_add = update_add_msg(110_000, 747_500, None, bob_onion);
let bob_node_signer = TestEcdhSigner { node_secret: bob_secret };
// Can't use the public API here as we need to avoid the CLTV delta checks (test vector uses
// < MIN_CLTV_EXPIRY_DELTA).
let (bob_peeled_onion, next_packet_details_opt) =
match onion_payment::decode_incoming_update_add_htlc_onion(
&bob_update_add, &bob_node_signer, &logger, &secp_ctx
) {
Ok(res) => res,
_ => panic!("Unexpected error")
};
let (carol_packet_bytes, carol_hmac) = if let onion_utils::Hop::BlindedForward {
next_hop_data: msgs::InboundOnionBlindedForwardPayload {
short_channel_id, payment_relay, payment_constraints, features, intro_node_blinding_point, next_blinding_override
}, next_hop_hmac, new_packet_bytes, ..
} = bob_peeled_onion {
assert_eq!(short_channel_id, 1729);
assert!(next_blinding_override.is_none());
assert_eq!(intro_node_blinding_point, Some(bob_blinding_point));
assert_eq!(payment_relay, PaymentRelay { cltv_expiry_delta: 36, fee_proportional_millionths: 150, fee_base_msat: 10_000 });
assert_eq!(features, BlindedHopFeatures::empty());
assert_eq!(payment_constraints, PaymentConstraints { max_cltv_expiry: 748_005, htlc_minimum_msat: 1500 });
(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,
Some(pubkey_from_hex("034e09f450a80c3d252b258aba0a61215bf60dda3b0dc78ffb0736ea1259dfd8a0")),
carol_onion
);
let carol_node_signer = TestEcdhSigner { node_secret: carol_secret };
let (carol_peeled_onion, next_packet_details_opt) =
match onion_payment::decode_incoming_update_add_htlc_onion(
&carol_update_add, &carol_node_signer, &logger, &secp_ctx
) {
Ok(res) => res,
_ => panic!("Unexpected error")
};
let (dave_packet_bytes, dave_hmac) = if let onion_utils::Hop::BlindedForward {
next_hop_data: msgs::InboundOnionBlindedForwardPayload {
short_channel_id, payment_relay, payment_constraints, features, intro_node_blinding_point, next_blinding_override
}, next_hop_hmac, new_packet_bytes, ..
} = carol_peeled_onion {
assert_eq!(short_channel_id, 1105);
assert_eq!(next_blinding_override, Some(pubkey_from_hex("031b84c5567b126440995d3ed5aaba0565d71e1834604819ff9c17f5e9d5dd078f")));
assert!(intro_node_blinding_point.is_none());
assert_eq!(payment_relay, PaymentRelay { cltv_expiry_delta: 48, fee_proportional_millionths: 100, fee_base_msat: 500 });
assert_eq!(features, BlindedHopFeatures::empty());
assert_eq!(payment_constraints, PaymentConstraints { max_cltv_expiry: 747_969, htlc_minimum_msat: 1500 });
(new_packet_bytes, next_hop_hmac)
} else { panic!() };

let dave_packet_details = next_packet_details_opt.unwrap();
let dave_onion = msgs::OnionPacket {
version: 0,
public_key: dave_packet_details.next_packet_pubkey,
hop_data: dave_packet_bytes,
hmac: dave_hmac,
};
let dave_update_add = update_add_msg(
dave_packet_details.outgoing_amt_msat, dave_packet_details.outgoing_cltv_value,
Some(pubkey_from_hex("031b84c5567b126440995d3ed5aaba0565d71e1834604819ff9c17f5e9d5dd078f")),
dave_onion
);
let dave_node_signer = TestEcdhSigner { node_secret: dave_secret };
let (dave_peeled_onion, next_packet_details_opt) =
match onion_payment::decode_incoming_update_add_htlc_onion(
&dave_update_add, &dave_node_signer, &logger, &secp_ctx
) {
Ok(res) => res,
_ => panic!("Unexpected error")
};
let (eve_packet_bytes, eve_hmac) = if let onion_utils::Hop::BlindedForward {
next_hop_data: msgs::InboundOnionBlindedForwardPayload {
short_channel_id, payment_relay, payment_constraints, features, intro_node_blinding_point, next_blinding_override
}, next_hop_hmac, new_packet_bytes, ..
} = dave_peeled_onion {
assert_eq!(short_channel_id, 561);
assert!(next_blinding_override.is_none());
assert!(intro_node_blinding_point.is_none());
assert_eq!(payment_relay, PaymentRelay { cltv_expiry_delta: 144, fee_proportional_millionths: 250, fee_base_msat: 0 });
assert_eq!(features, BlindedHopFeatures::empty());
assert_eq!(payment_constraints, PaymentConstraints { max_cltv_expiry: 747_921, htlc_minimum_msat: 1500 });
(new_packet_bytes, next_hop_hmac)
} else { panic!() };

let eve_packet_details = next_packet_details_opt.unwrap();
let eve_onion = msgs::OnionPacket {
version: 0,
public_key: eve_packet_details.next_packet_pubkey,
hop_data: eve_packet_bytes,
hmac: eve_hmac,
};
let eve_update_add = update_add_msg(
eve_packet_details.outgoing_amt_msat, eve_packet_details.outgoing_cltv_value,
Some(pubkey_from_hex("03e09038ee76e50f444b19abf0a555e8697e035f62937168b80adf0931b31ce52a")),
eve_onion
);
let eve_node_signer = TestEcdhSigner { node_secret: eve_secret };
// We can't decode the final payload because it contains a path_id and is missing some LDK
// specific fields.
// < MIN_CLTV_EXPIRY_DELTA). The vector includes an unknown odd encrypted TLV (type 561) in the
// blinded payload for Bob, which should now be rejected instead of forwarded.
match onion_payment::decode_incoming_update_add_htlc_onion(
&eve_update_add, &eve_node_signer, &logger, &secp_ctx
&bob_update_add, &bob_node_signer, &logger, &secp_ctx
) {
Err((HTLCFailureMsg::Malformed(msg), _)) => assert_eq!(msg.failure_code,
LocalHTLCFailureReason::InvalidOnionBlinding.failure_code()),
Err((HTLCFailureMsg::Relay(_), LocalHTLCFailureReason::InvalidOnionPayload)) => {},
_ => panic!("Unexpected error")
}
}
Expand Down
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