+ #[test]
+ fn fail_construct_onion_on_too_big_payloads() {
+ // Ensure that if we call `construct_onion_packet` and friends where payloads are too large for
+ // the allotted packet length, we'll fail to construct. Previously, senders would happily
+ // construct invalid packets by array-shifting the final node's HMAC out of the packet when
+ // adding an intermediate onion layer, causing the receiver to error with "final payload
+ // provided for us as an intermediate node."
+ let secp_ctx = Secp256k1::new();
+ let bob = crate::sign::KeysManager::new(&[2; 32], 42, 42);
+ let bob_pk = PublicKey::from_secret_key(&secp_ctx, &bob.get_node_secret_key());
+ let charlie = crate::sign::KeysManager::new(&[3; 32], 42, 42);
+ let charlie_pk = PublicKey::from_secret_key(&secp_ctx, &charlie.get_node_secret_key());
+
+ let (
+ session_priv, total_amt_msat, cur_height, mut recipient_onion, keysend_preimage, payment_hash,
+ prng_seed, hops, ..
+ ) = payment_onion_args(bob_pk, charlie_pk);
+
+ // Ensure the onion will not fit all the payloads by adding a large custom TLV.
+ recipient_onion.custom_tlvs.push((13377331, vec![0; 1156]));
+
+ let path = Path { hops, blinded_tail: None, };
+ let onion_keys = super::onion_utils::construct_onion_keys(&secp_ctx, &path, &session_priv).unwrap();
+ let (onion_payloads, ..) = super::onion_utils::build_onion_payloads(
+ &path, total_amt_msat, recipient_onion, cur_height + 1, &Some(keysend_preimage)
+ ).unwrap();
+
+ assert!(super::onion_utils::construct_onion_packet(
+ onion_payloads, onion_keys, prng_seed, &payment_hash
+ ).is_err());
+ }
+