From 345426fb50b7e80042ab6df2b8cd994ea9530658 Mon Sep 17 00:00:00 2001
From: Steven Barclay <stejbac@gmail.com>
Date: Wed, 18 Nov 2020 20:45:58 +0000
Subject: [PATCH] Add further validation checks for delayed payout tx

Do some extra sanity checks like tx.outputSum < tx.inputSum, to rule out
any edge cases where an invalid delayed payout tx might still arise.
---
 .../main/java/bisq/core/btc/wallet/TradeWalletService.java   | 4 ++++
 .../protocol/tasks/seller/SellerCreatesDelayedPayoutTx.java  | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/core/src/main/java/bisq/core/btc/wallet/TradeWalletService.java b/core/src/main/java/bisq/core/btc/wallet/TradeWalletService.java
index 0373a4a5dce..2b05f47c182 100644
--- a/core/src/main/java/bisq/core/btc/wallet/TradeWalletService.java
+++ b/core/src/main/java/bisq/core/btc/wallet/TradeWalletService.java
@@ -76,6 +76,7 @@
 
 public class TradeWalletService {
     private static final Logger log = LoggerFactory.getLogger(TradeWalletService.class);
+    private static final Coin MIN_DELAYED_PAYOUT_TX_FEE = Coin.valueOf(1000);
 
     private final WalletsSetup walletsSetup;
     private final Preferences preferences;
@@ -766,6 +767,9 @@ public Transaction finalizeUnconnectedDelayedPayoutTx(Transaction delayedPayoutT
         WalletService.printTx("finalizeDelayedPayoutTx", delayedPayoutTx);
         WalletService.verifyTransaction(delayedPayoutTx);
 
+        if (checkNotNull(inputValue).isLessThan(delayedPayoutTx.getOutputSum().add(MIN_DELAYED_PAYOUT_TX_FEE))) {
+            throw new TransactionVerificationException("Delayed payout tx is paying less than the minimum allowed tx fee");
+        }
         Script scriptPubKey = get2of2MultiSigOutputScript(buyerPubKey, sellerPubKey, false);
         input.getScriptSig().correctlySpends(delayedPayoutTx, 0, witness, inputValue, scriptPubKey, Script.ALL_VERIFY_FLAGS);
         return delayedPayoutTx;
diff --git a/core/src/main/java/bisq/core/trade/protocol/tasks/seller/SellerCreatesDelayedPayoutTx.java b/core/src/main/java/bisq/core/trade/protocol/tasks/seller/SellerCreatesDelayedPayoutTx.java
index ae9048bec7b..a466f112643 100644
--- a/core/src/main/java/bisq/core/trade/protocol/tasks/seller/SellerCreatesDelayedPayoutTx.java
+++ b/core/src/main/java/bisq/core/trade/protocol/tasks/seller/SellerCreatesDelayedPayoutTx.java
@@ -20,6 +20,7 @@
 import bisq.core.btc.wallet.TradeWalletService;
 import bisq.core.dao.governance.param.Param;
 import bisq.core.trade.Trade;
+import bisq.core.trade.TradeDataValidation;
 import bisq.core.trade.protocol.tasks.TradeTask;
 
 import bisq.common.taskrunner.TaskRunner;
@@ -53,6 +54,10 @@ protected void run() {
                     donationAddressString,
                     minerFee,
                     lockTime);
+            TradeDataValidation.validateDelayedPayoutTx(trade,
+                    preparedDelayedPayoutTx,
+                    processModel.getDaoFacade(),
+                    processModel.getBtcWalletService());
 
             processModel.setPreparedDelayedPayoutTx(preparedDelayedPayoutTx);