Fail blinded received HTLCs if they violate PaymentConstraints

[rust-lightning] / lightning / src / ln / onion_payment.rs

diff --git a/lightning/src/ln/onion_payment.rs b/lightning/src/ln/onion_payment.rs
index c92c8fd24cd670c1fa5e82c73ca130568b5a1542..8767e2500bdaa4769cc7b5db18c07ebf258db8f7 100644 (file)
--- a/lightning/src/ln/onion_payment.rs
+++ b/lightning/src/ln/onion_payment.rs
@@ -33,6 +33,15 @@ pub struct InboundOnionErr {
        pub msg: &'static str,
 }
 
+fn check_blinded_payment_constraints(
+       amt_msat: u64, cltv_expiry: u32, constraints: &PaymentConstraints
+) -> Result<(), ()> {
+       if amt_msat < constraints.htlc_minimum_msat ||
+               cltv_expiry > constraints.max_cltv_expiry
+       { return Err(()) }
+       Ok(())
+}
+
 fn check_blinded_forward(
        inbound_amt_msat: u64, inbound_cltv_expiry: u32, payment_relay: &PaymentRelay,
        payment_constraints: &PaymentConstraints, features: &BlindedHopFeatures
@@ -43,9 +52,8 @@ fn check_blinded_forward(
        let outgoing_cltv_value = inbound_cltv_expiry.checked_sub(
                payment_relay.cltv_expiry_delta as u32
        ).ok_or(())?;
-       if inbound_amt_msat < payment_constraints.htlc_minimum_msat ||
-               outgoing_cltv_value > payment_constraints.max_cltv_expiry
-               { return Err(()) }
+       check_blinded_payment_constraints(inbound_amt_msat, outgoing_cltv_value, payment_constraints)?;
+
        if features.requires_unknown_bits_from(&BlindedHopFeatures::empty()) { return Err(()) }
        Ok((amt_to_forward, outgoing_cltv_value))
 }
@@ -122,8 +130,17 @@ pub(super) fn create_recv_pending_htlc_info(
                        (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata,
                         false),
                msgs::InboundOnionPayload::BlindedReceive {
-                       amt_msat, total_msat, outgoing_cltv_value, payment_secret, intro_node_blinding_point, ..
+                       amt_msat, total_msat, outgoing_cltv_value, payment_secret, intro_node_blinding_point,
+                       payment_constraints, ..
                } => {
+                       check_blinded_payment_constraints(amt_msat, cltv_expiry, &payment_constraints)
+                               .map_err(|()| {
+                                       InboundOnionErr {
+                                               err_code: INVALID_ONION_BLINDING,
+                                               err_data: vec![0; 32],
+                                               msg: "Amount or cltv_expiry violated blinded payment constraints",
+                                       }
+                               })?;
                        let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
                        (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None,
                         intro_node_blinding_point.is_none())