Paper/patches/server/0876-Do-not-read-tile-entities-in-chunks-that-are-positio.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sun, 18 Jun 2023 23:04:46 -0700
Subject: [PATCH] Do not read tile entities in chunks that are positioned
 outside of the chunk

The tile entities are not accessible and so should not be loaded.
This can happen as a result of users moving regionfiles around,
which would cause a crash on Folia but would appear to function
fine on Paper.

diff --git a/src/main/java/net/minecraft/world/level/chunk/storage/SerializableChunkData.java b/src/main/java/net/minecraft/world/level/chunk/storage/SerializableChunkData.java
index d7a204216332ccbd6bece23bd507be0366ea4d61..b86b3bf713668999a21c4120b1d16c295531b2ad 100644
--- a/src/main/java/net/minecraft/world/level/chunk/storage/SerializableChunkData.java
+++ b/src/main/java/net/minecraft/world/level/chunk/storage/SerializableChunkData.java
@@ -363,6 +363,13 @@ public record SerializableChunkData(Registry<Biome> biomeRegistry, ChunkPos chun
 
             while (iterator2.hasNext()) {
                 nbttagcompound = (CompoundTag) iterator2.next();
+                // Paper start - do not read tile entities positioned outside the chunk
+                final BlockPos blockposition = BlockEntity.getPosFromTag(nbttagcompound);
+                if ((blockposition.getX() >> 4) != chunkPos.x || (blockposition.getZ() >> 4) != chunkPos.z) {
+                    LOGGER.warn("Tile entity serialized in chunk {} in world '{}' positioned at {} is located outside of the chunk", chunkPos, world.getWorld().getName(), blockposition);
+                    continue;
+                }
+                // Paper end - do not read tile entities positioned outside the chunk
                 protochunk1.setBlockEntityNbt(nbttagcompound);
             }
 
@@ -616,6 +623,13 @@ public record SerializableChunkData(Registry<Biome> biomeRegistry, ChunkPos chun
                     chunk.setBlockEntityNbt(nbttagcompound);
                 } else {
                     BlockPos blockposition = BlockEntity.getPosFromTag(nbttagcompound);
+                    // Paper start - do not read tile entities positioned outside the chunk
+                    ChunkPos chunkPos = chunk.getPos();
+                    if ((blockposition.getX() >> 4) != chunkPos.x || (blockposition.getZ() >> 4) != chunkPos.z) {
+                        LOGGER.warn("Tile entity serialized in chunk " + chunkPos + " in world '" + world.getWorld().getName() + "' positioned at " + blockposition + " is located outside of the chunk");
+                        continue;
+                    }
+                    // Paper end - do not read tile entities positioned outside the chunk
                     BlockEntity tileentity = BlockEntity.loadStatic(blockposition, chunk.getBlockState(blockposition), nbttagcompound, world.registryAccess());
 
                     if (tileentity != null) {