Merge pull request #9269 from hieblmi/sendpayment-fix-negative-feelimit

routerrpc: fix sendpayment_v2 negative fee limit

docs/release-notes/release-notes-0.19.0.md

@@ -28,10 +28,14 @@
   does not contain a payment address.
 
 * [Fixed a bug](https://github.com/lightningnetwork/lnd/pull/9033) where we
-  would not signal an error when trying to bump an non-anchor channel but
+  would not signal an error when trying to bump a non-anchor channel but
   instead report a successful cpfp registration although no fee bumping is
   possible for non-anchor channels anyways.
 
+* [Fixed a bug](https://github.com/lightningnetwork/lnd/pull/9269) where a
+  negative fee limit for `SendPaymentV2` would lead to omitting the fee limit
+  check.
+
 * [Use the required route blinding 
   feature-bit](https://github.com/lightningnetwork/lnd/pull/9143) for invoices 
   containing blinded paths.
@@ -196,6 +200,7 @@ The underlying functionality between those two options remain the same.
 * CharlieZKSmith
 * Elle Mouton
 * George Tsagkarelis
+* hieblmi
 * Oliver Gugger
 * Pins
 * Viktor Tigerström

lnrpc/marshall_utils.go

@@ -23,6 +23,9 @@ var (
 	ErrSatMsatMutualExclusive = errors.New(
 		"sat and msat arguments are mutually exclusive",
 	)
+
+	// ErrNegativeAmt is returned when a negative amount is specified.
+	ErrNegativeAmt = errors.New("amount cannot be negative")
 )
 
 // CalculateFeeLimit returns the fee limit in millisatoshis. If a percentage
@@ -56,6 +59,10 @@ func UnmarshallAmt(amtSat, amtMsat int64) (lnwire.MilliSatoshi, error) {
 		return 0, ErrSatMsatMutualExclusive
 	}
 
+	if amtSat < 0 || amtMsat < 0 {
+		return 0, ErrNegativeAmt
+	}
+
 	if amtSat != 0 {
 		return lnwire.NewMSatFromSatoshis(btcutil.Amount(amtSat)), nil
 	}