From 4237539e5877dcc0a59f66a56b002fb17b6ff85e Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sat, 11 Jan 2020 22:32:44 -0800
Subject: [PATCH] Guard against serializing mismatching chunk coordinate
 (#2844)

Should help if something dumb happens
---
 ...rializing-mismatching-chunk-coordina.patch | 57 +++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 Spigot-Server-Patches/0422-Guard-against-serializing-mismatching-chunk-coordina.patch

diff --git a/Spigot-Server-Patches/0422-Guard-against-serializing-mismatching-chunk-coordina.patch b/Spigot-Server-Patches/0422-Guard-against-serializing-mismatching-chunk-coordina.patch
new file mode 100644
index 000000000..d390dbcb1
--- /dev/null
+++ b/Spigot-Server-Patches/0422-Guard-against-serializing-mismatching-chunk-coordina.patch
@@ -0,0 +1,57 @@
+From 4feed34cc8482b201d1c0a61edc1590991e19016 Mon Sep 17 00:00:00 2001
+From: Spottedleaf <Spottedleaf@users.noreply.github.com>
+Date: Fri, 27 Dec 2019 09:42:26 -0800
+Subject: [PATCH] Guard against serializing mismatching chunk coordinate
+
+Should help if something dumb happens
+
+diff --git a/src/main/java/net/minecraft/server/ChunkRegionLoader.java b/src/main/java/net/minecraft/server/ChunkRegionLoader.java
+index 26f1a4b09..4349d22cc 100644
+--- a/src/main/java/net/minecraft/server/ChunkRegionLoader.java
++++ b/src/main/java/net/minecraft/server/ChunkRegionLoader.java
+@@ -23,6 +23,13 @@ public class ChunkRegionLoader {
+ 
+     private static final Logger LOGGER = LogManager.getLogger();
+ 
++    // Paper start - guard against serializing mismatching coordinates
++    // TODO Note: This needs to be re-checked each update
++    public static ChunkCoordIntPair getChunkCoordinate(NBTTagCompound chunkData) {
++        NBTTagCompound levelData = chunkData.getCompound("Level");
++        return new ChunkCoordIntPair(levelData.getInt("xPos"), levelData.getInt("zPos"));
++    }
++    // Paper end
+     // Paper start
+     public static final class InProgressChunkHolder {
+ 
+@@ -48,8 +55,8 @@ public class ChunkRegionLoader {
+         // Paper end
+         ChunkGenerator<?> chunkgenerator = worldserver.getChunkProvider().getChunkGenerator();
+         WorldChunkManager worldchunkmanager = chunkgenerator.getWorldChunkManager();
+-        NBTTagCompound nbttagcompound1 = nbttagcompound.getCompound("Level");
+-        ChunkCoordIntPair chunkcoordintpair1 = new ChunkCoordIntPair(nbttagcompound1.getInt("xPos"), nbttagcompound1.getInt("zPos"));
++        NBTTagCompound nbttagcompound1 = nbttagcompound.getCompound("Level"); // Paper - diff on change, see ChunkRegionLoader#getChunkCoordinate
++        ChunkCoordIntPair chunkcoordintpair1 = new ChunkCoordIntPair(nbttagcompound1.getInt("xPos"), nbttagcompound1.getInt("zPos")); // Paper - diff on change, see ChunkRegionLoader#getChunkCoordinate
+ 
+         if (!Objects.equals(chunkcoordintpair, chunkcoordintpair1)) {
+             ChunkRegionLoader.LOGGER.error("Chunk file at {} is in the wrong location; relocating. (Expected {}, got {})", chunkcoordintpair, chunkcoordintpair, chunkcoordintpair1);
+diff --git a/src/main/java/net/minecraft/server/IChunkLoader.java b/src/main/java/net/minecraft/server/IChunkLoader.java
+index 134c76065..25c8b131f 100644
+--- a/src/main/java/net/minecraft/server/IChunkLoader.java
++++ b/src/main/java/net/minecraft/server/IChunkLoader.java
+@@ -106,6 +106,13 @@ public class IChunkLoader extends RegionFileCache implements AutoCloseable {
+ //
+     public void a(ChunkCoordIntPair chunkcoordintpair, NBTTagCompound nbttagcompound) throws IOException { write(chunkcoordintpair, nbttagcompound); } // Paper OBFHELPER
+     public void write(ChunkCoordIntPair chunkcoordintpair, NBTTagCompound nbttagcompound) throws IOException { // Paper - OBFHELPER - (Switched around for safety)
++        // Paper start
++        if (!chunkcoordintpair.equals(ChunkRegionLoader.getChunkCoordinate(nbttagcompound))) {
++            String world = (this instanceof PlayerChunkMap) ? ((PlayerChunkMap)this).world.getWorld().getName() : null;
++            throw new IllegalArgumentException("Chunk coordinate and serialized data do not have matching coordinates, trying to serialize coordinate " + chunkcoordintpair.toString()
++                + " but compound says coordinate is " + ChunkRegionLoader.getChunkCoordinate(nbttagcompound).toString() + (world == null ? " for an unknown world" : (" for world: " + world)));
++        }
++        // Paper end
+         super.write(chunkcoordintpair, nbttagcompound);
+         if (this.c != null) {
+             synchronized (this.persistentDataLock) { // Paper - Async chunk loading
+-- 
+2.24.1
+