Overpayment factor (#853)

* chore: bump Eclair to v0.12.0

* feat: add overpayment check for actual > expected * 2

Author: michael1011

docker/build.py

@@ -46,7 +46,7 @@ class Image:
 GETH_VERSION = "1.15.5"
 
 C_LIGHTNING_VERSION = "25.02"
-ECLAIR_VERSION = "0.11.0"
+ECLAIR_VERSION = "0.12.0"
 LND_VERSION = "0.18.5-beta"
 
 BITCOIN_BUILD_ARG = BuildArgument(

lib/swap/OverpaymentProtector.ts

@@ -37,10 +37,10 @@ class OverpaymentProtector {
     } else {
       return (
         actual - expected >
-        Math.max(
-          this.overPaymentExemptAmount,
-          actual * this.overPaymentMaxPercentage,
-        )
+          Math.max(
+            this.overPaymentExemptAmount,
+            expected * this.overPaymentMaxPercentage,
+          ) || actual > expected * 2
       );
     }
   };

test/unit/swap/OverpaymentProtector.spec.ts

@@ -126,5 +126,24 @@ describe('OverpaymentProtector', () => {
         ).toEqual(expectedResult);
       },
     );
+
+    test.each`
+      expected | actual  | config                                        | expectedResult
+      ${100}   | ${150}  | ${{ exemptAmount: 500, maxPercentage: 60 }}   | ${false}
+      ${100}   | ${150}  | ${{ exemptAmount: 500, maxPercentage: 40 }}   | ${false}
+      ${100}   | ${300}  | ${{ exemptAmount: 500, maxPercentage: 1 }}    | ${true}
+      ${5000}  | ${5500} | ${{ exemptAmount: 100, maxPercentage: 1 }}    | ${true}
+      ${1020}  | ${3000} | ${{ exemptAmount: 10_000, maxPercentage: 2 }} | ${true}
+    `(
+      'should not allow overpayment when actual > expected * 2',
+      ({ expected, actual, config, expectedResult }) => {
+        expect(
+          new OverpaymentProtector(
+            Logger.disabledLogger,
+            config,
+          ).isUnacceptableOverpay(SwapType.Submarine, expected, actual),
+        ).toEqual(expectedResult);
+      },
+    );
   });
 });