From a3c44428d35cafbce948416a5bcaf68e7891da27 Mon Sep 17 00:00:00 2001
From: catbref <misc-github@talk2dom.com>
Date: Wed, 4 Mar 2020 15:41:47 +0000
Subject: [PATCH] Restrict TRANSFER_PRIVS recipients to new (non-existent)
 accounts.

---
 .../org/qortal/transaction/Transaction.java   |  1 +
 .../transaction/TransferPrivsTransaction.java | 11 +++++++--
 .../org/qortal/test/TransferPrivsTests.java   | 24 +++++++++++++++++++
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/main/java/org/qortal/transaction/Transaction.java b/src/main/java/org/qortal/transaction/Transaction.java
index adf70310..75e31f8c 100644
--- a/src/main/java/org/qortal/transaction/Transaction.java
+++ b/src/main/java/org/qortal/transaction/Transaction.java
@@ -241,6 +241,7 @@ public abstract class Transaction {
 		ASSET_NOT_SPENDABLE(89),
 		ACCOUNT_CANNOT_REWARD_SHARE(90),
 		SELF_SHARE_EXISTS(91),
+		ACCOUNT_ALREADY_EXISTS(92),
 		NOT_YET_RELEASED(1000);
 
 		public final int value;
diff --git a/src/main/java/org/qortal/transaction/TransferPrivsTransaction.java b/src/main/java/org/qortal/transaction/TransferPrivsTransaction.java
index 8a4cd2bf..9716cfa5 100644
--- a/src/main/java/org/qortal/transaction/TransferPrivsTransaction.java
+++ b/src/main/java/org/qortal/transaction/TransferPrivsTransaction.java
@@ -83,6 +83,10 @@ public class TransferPrivsTransaction extends Transaction {
 		if (!Crypto.isValidAddress(this.transferPrivsTransactionData.getRecipient()))
 			return ValidationResult.INVALID_ADDRESS;
 
+		// Check recipient is new account
+		if (this.repository.getAccountRepository().accountExists(this.transferPrivsTransactionData.getRecipient()))
+			return ValidationResult.ACCOUNT_ALREADY_EXISTS;
+
 		return ValidationResult.OK;
 	}
 
@@ -183,8 +187,11 @@ public class TransferPrivsTransaction extends Transaction {
 		accountRepository.setFlags(senderData);
 
 		// Restore recipient's flags
-		recipientData.setFlags(this.transferPrivsTransactionData.getPreviousRecipientFlags());
-		accountRepository.setFlags(recipientData);
+		Integer previousRecipientFlags = this.transferPrivsTransactionData.getPreviousRecipientFlags();
+		if (previousRecipientFlags != null) {
+			recipientData.setFlags(previousRecipientFlags);
+			accountRepository.setFlags(recipientData);
+		}
 
 		// Clean values in transaction data
 		this.transferPrivsTransactionData.setPreviousSenderFlags(null);
diff --git a/src/test/java/org/qortal/test/TransferPrivsTests.java b/src/test/java/org/qortal/test/TransferPrivsTests.java
index 71eb1292..f81d7e34 100644
--- a/src/test/java/org/qortal/test/TransferPrivsTests.java
+++ b/src/test/java/org/qortal/test/TransferPrivsTests.java
@@ -5,6 +5,7 @@ import org.junit.Before;
 import org.junit.Test;
 import org.qortal.account.Account;
 import org.qortal.account.PrivateKeyAccount;
+import org.qortal.account.PublicKeyAccount;
 import org.qortal.block.BlockChain;
 import org.qortal.block.BlockMinter;
 import org.qortal.data.account.AccountData;
@@ -19,11 +20,13 @@ import org.qortal.test.common.BlockUtils;
 import org.qortal.test.common.Common;
 import org.qortal.test.common.TestAccount;
 import org.qortal.test.common.TransactionUtils;
+import org.qortal.transform.Transformer;
 
 import static org.junit.Assert.*;
 
 import java.math.BigDecimal;
 import java.util.List;
+import java.util.Random;
 
 public class TransferPrivsTests extends Common {
 
@@ -42,6 +45,27 @@ public class TransferPrivsTests extends Common {
 		Common.orphanCheck();
 	}
 
+	@Test
+	public void testAliceIntoNewAccountTransferPrivs() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			TestAccount alice = Common.getTestAccount(repository, "alice");
+			assertTrue(alice.canMint());
+
+			PrivateKeyAccount aliceMintingAccount = Common.getTestAccount(repository, "alice-reward-share");
+
+			byte[] randomPublicKey = new byte[Transformer.PUBLIC_KEY_LENGTH];
+			Random random = new Random();
+			random.nextBytes(randomPublicKey);
+
+			Account randomAccount = new PublicKeyAccount(repository, randomPublicKey);
+
+			combineAccounts(repository, alice, randomAccount, aliceMintingAccount);
+
+			assertFalse(alice.canMint());
+			assertTrue(randomAccount.canMint());
+		}
+	}
+
 	@Test
 	public void testAliceIntoDilbertTransferPrivs() throws DataException {
 		try (final Repository repository = RepositoryManager.getRepository()) {