From a2e1efab9067ec8b7f04429c9aa4ed4c0e323a97 Mon Sep 17 00:00:00 2001
From: CalDescent <caldescent@protonmail.com>
Date: Sat, 25 Jun 2022 14:12:21 +0100
Subject: [PATCH] Synchronize hasInvalidBlock predicate, as it wasn't thread
 safe

---
 .../org/qortal/controller/Controller.java     | 50 ++++++++++---------
 src/main/java/org/qortal/network/Peer.java    |  2 +-
 2 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/src/main/java/org/qortal/controller/Controller.java b/src/main/java/org/qortal/controller/Controller.java
index 1a4decb6..64a30fae 100644
--- a/src/main/java/org/qortal/controller/Controller.java
+++ b/src/main/java/org/qortal/controller/Controller.java
@@ -723,39 +723,41 @@ public class Controller extends Thread {
 	};
 
 	public static final Predicate<Peer> hasInvalidBlock = peer -> {
-		final PeerChainTipData peerChainTipData = peer.getChainTipData();
-		Map<ByteArray, Long> invalidBlockSignatures = Synchronizer.getInstance().getInvalidBlockSignatures();
-		List<byte[]> peerSignatures = new ArrayList<>();
+		synchronized (peer.peerInfoLock) {
+			final PeerChainTipData peerChainTipData = peer.getChainTipData();
+			Map<ByteArray, Long> invalidBlockSignatures = Synchronizer.getInstance().getInvalidBlockSignatures();
+			List<byte[]> peerSignatures = new ArrayList<>();
 
-		// Add peer's latest block signature
-		if (peerChainTipData != null) {
-			peerSignatures.add(peerChainTipData.getLastBlockSignature());
-		}
+			// Add peer's latest block signature
+			if (peerChainTipData != null) {
+				peerSignatures.add(peerChainTipData.getLastBlockSignature());
+			}
 
-		// Add peer's blocks since common block
-		if (peer.getCommonBlockData() != null) {
-			List<BlockSummaryData> peerSummaries = peer.getCommonBlockData().getBlockSummariesAfterCommonBlock();
-			if (peerSummaries != null) {
-				for (BlockSummaryData blockSummaryData : peerSummaries) {
-					peerSignatures.add(blockSummaryData.getSignature());
+			// Add peer's blocks since common block
+			if (peer.getCommonBlockData() != null) {
+				List<BlockSummaryData> peerSummaries = peer.getCommonBlockData().getBlockSummariesAfterCommonBlock();
+				if (peerSummaries != null) {
+					for (BlockSummaryData blockSummaryData : peerSummaries) {
+						peerSignatures.add(blockSummaryData.getSignature());
+					}
 				}
 			}
-		}
 
-		// Shortcut if no data
-		if (peerSignatures.isEmpty() || invalidBlockSignatures == null || invalidBlockSignatures.isEmpty()) {
-			return false;
-		}
+			// Shortcut if no data
+			if (peerSignatures.isEmpty() || invalidBlockSignatures == null || invalidBlockSignatures.isEmpty()) {
+				return false;
+			}
 
-		// Loop through our known invalid blocks and check each one against supplied block summaries
-		for (ByteArray invalidSignature : invalidBlockSignatures.keySet()) {
-			for (byte[] peerSignature : peerSignatures) {
-				if (Arrays.equals(peerSignature, invalidSignature.value)) {
-					return true;
+			// Loop through our known invalid blocks and check each one against supplied block summaries
+			for (ByteArray invalidSignature : invalidBlockSignatures.keySet()) {
+				for (byte[] peerSignature : peerSignatures) {
+					if (Arrays.equals(peerSignature, invalidSignature.value)) {
+						return true;
+					}
 				}
 			}
+			return false;
 		}
-		return false;
 	};
 
 	public static final Predicate<Peer> hasNoRecentBlock = peer -> {
diff --git a/src/main/java/org/qortal/network/Peer.java b/src/main/java/org/qortal/network/Peer.java
index f99a94b1..2b3f597a 100644
--- a/src/main/java/org/qortal/network/Peer.java
+++ b/src/main/java/org/qortal/network/Peer.java
@@ -121,7 +121,7 @@ public class Peer {
 
     // Peer info
 
-    private final Object peerInfoLock = new Object();
+    public final Object peerInfoLock = new Object();
 
     private String peersNodeId;
     private byte[] peersPublicKey;