Prevent creation of on-chain invoices below the dust limit

BTCPayServer.Client/BTCPayServer.Client.csproj

@@ -27,7 +27,7 @@
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0" PrivateAssets="All" />
   </ItemGroup>
     <ItemGroup>
-      <PackageReference Include="NBitcoin" Version="6.0.15" />
+      <PackageReference Include="NBitcoin" Version="6.0.17" />
       <PackageReference Include="BTCPayServer.Lightning.Common" Version="1.2.7" />
       <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
     </ItemGroup>

BTCPayServer.Tests/SeleniumTests.cs

@@ -493,7 +493,7 @@ public async Task CanUsePairing()
                 var client = new NBitpayClient.Bitpay(new Key(), s.ServerUri);
                 await client.AuthorizeClient(new NBitpayClient.PairingCode(pairingCode));
                 await client.CreateInvoiceAsync(
-                    new NBitpayClient.Invoice() { Price = 0.000000012m, Currency = "USD", FullNotifications = true },
+                    new NBitpayClient.Invoice() { Price = 1.000000012m, Currency = "USD", FullNotifications = true },
                     NBitpayClient.Facade.Merchant);
 
                 client = new NBitpayClient.Bitpay(new Key(), s.ServerUri);
@@ -503,7 +503,7 @@ public async Task CanUsePairing()
                 s.Driver.FindElement(By.Id("ApprovePairing")).Click();
 
                 await client.CreateInvoiceAsync(
-                    new NBitpayClient.Invoice() { Price = 0.000000012m, Currency = "USD", FullNotifications = true },
+                    new NBitpayClient.Invoice() { Price = 1.000000012m, Currency = "USD", FullNotifications = true },
                     NBitpayClient.Facade.Merchant);
 
                 s.Driver.Navigate().GoToUrl(s.Link("/api-tokens"));

BTCPayServer.Tests/UnitTest1.cs

@@ -2984,15 +2984,31 @@ public async Task CanCreateAndDeleteApps()
 
         [Fact(Timeout = LongRunningTestTimeout)]
         [Trait("Integration", "Integration")]
+        [Trait("Lightning", "Lightning")]
         public async Task CanCreateStrangeInvoice()
         {
             using (var tester = ServerTester.Create())
             {
+                tester.ActivateLightning();
                 await tester.StartAsync();
                 var user = tester.NewAccount();
-                user.GrantAccess();
+                user.GrantAccess(true);
                 user.RegisterDerivationScheme("BTC");
+
                 DateTimeOffset expiration = DateTimeOffset.UtcNow + TimeSpan.FromMinutes(21);
+
+                // This should fail, the amount is too low to be above the dust limit of bitcoin
+                var ex = Assert.Throws<BitPayException>(() => user.BitPay.CreateInvoice(
+                    new Invoice()
+                    {
+                        Price = 0.000000012m,
+                        Currency = "USD",
+                        FullNotifications = true,
+                        ExpirationTime = expiration
+                    }, Facade.Merchant));
+                Assert.Contains("dust threshold", ex.Message);
+                await user.RegisterLightningNodeAsync("BTC");
+
                 var invoice1 = user.BitPay.CreateInvoice(
                     new Invoice()
                     {
@@ -3001,6 +3017,7 @@ public async Task CanCreateStrangeInvoice()
                         FullNotifications = true,
                         ExpirationTime = expiration
                     }, Facade.Merchant);
+
                 Assert.Equal(expiration.ToUnixTimeSeconds(), invoice1.ExpirationTime.ToUnixTimeSeconds());
                 var invoice2 = user.BitPay.CreateInvoice(new Invoice() { Price = 0.000000019m, Currency = "USD" },
                     Facade.Merchant);

BTCPayServer/BTCPayServer.csproj

@@ -1,4 +1,4 @@
- <Project Sdk="Microsoft.NET.Sdk.Web">
+ <Project Sdk="Microsoft.NET.Sdk.Web">
   <Import Project="../Build/Version.csproj" Condition="Exists('../Build/Version.csproj')" />
   <Import Project="../Build/Common.csproj" />
 

BTCPayServer/Data/Payouts/BitcoinLike/BitcoinLikePayoutHandler.cs

@@ -136,7 +136,7 @@ public Task<decimal> GetMinimumPayoutAmount(PaymentMethodId paymentMethodId, ICl
             claimDestination is IBitcoinLikeClaimDestination bitcoinLikeClaimDestination)
         {
             txout.ScriptPubKey = bitcoinLikeClaimDestination.Address.ScriptPubKey;
-            return Task.FromResult(txout.GetDustThreshold(new FeeRate(1.0m)).ToDecimal(MoneyUnit.BTC));
+            return Task.FromResult(txout.GetDustThreshold().ToDecimal(MoneyUnit.BTC));
         }
 
         return Task.FromResult(0m);

BTCPayServer/Payments/Bitcoin/BitcoinLikePaymentHandler.cs

@@ -190,6 +190,15 @@ private string GetPaymentMethodName(BTCPayNetworkBase network)
             }
 
             var reserved = await prepare.ReserveAddress;
+            if (paymentMethod.ParentEntity.Type != InvoiceType.TopUp)
+            {
+                var txOut = network.NBitcoinNetwork.Consensus.ConsensusFactory.CreateTxOut();
+                txOut.ScriptPubKey = reserved.Address.ScriptPubKey;
+                var dust = txOut.GetDustThreshold();
+                var amount = paymentMethod.Calculate().Due;
+                if (amount < dust)
+                    throw new PaymentMethodUnavailableException("Amount below the dust threshold. For amounts of this size, it is recommended to enable an off-chain (Lightning) payment method");
+            }
             onchainMethod.DepositAddress = reserved.Address.ToString();
             onchainMethod.KeyPath = reserved.KeyPath;
             onchainMethod.PayjoinEnabled = blob.PayJoinEnabled &&

BTCPayServer/Payments/PayJoin/PayJoinEndpointController.cs

@@ -424,7 +424,7 @@ ObjectResult CreatePayjoinErrorAndLog(int httpCode, PayjoinReceiverWellknownErro
                     {
                         var outputContribution = Money.Min(additionalFee, -due);
                         outputContribution = Money.Min(outputContribution,
-                            newTx.Outputs[i].Value - newTx.Outputs[i].GetDustThreshold(minRelayTxFee));
+                            newTx.Outputs[i].Value - newTx.Outputs[i].GetDustThreshold());
                         newTx.Outputs[i].Value -= outputContribution;
                         additionalFee -= outputContribution;
                         due += outputContribution;
@@ -437,7 +437,7 @@ ObjectResult CreatePayjoinErrorAndLog(int httpCode, PayjoinReceiverWellknownErro
                 {
                     var outputContribution = Money.Min(additionalFee, feeOutput.Value);
                     outputContribution = Money.Min(outputContribution,
-                        feeOutput.Value - feeOutput.GetDustThreshold(minRelayTxFee));
+                        feeOutput.Value - feeOutput.GetDustThreshold());
                     outputContribution = Money.Min(outputContribution, allowedSenderFeeContribution);
                     feeOutput.Value -= outputContribution;
                     additionalFee -= outputContribution;