Scissors/patches/server/0014-Block-server-side-chunkbans.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: ayunami2000 <spwilliamsiam@gmail.com>
Date: Thu, 25 Jan 2024 23:48:51 -0600
Subject: [PATCH] Block server-side chunkbans


diff --git a/src/main/java/net/minecraft/network/PacketEncoder.java b/src/main/java/net/minecraft/network/PacketEncoder.java
index 85b8be8ffac0fb40e9cae0528271ed41473811c8..d0cfc4fc00d45c91380d2d794ca816db74d40266 100644
--- a/src/main/java/net/minecraft/network/PacketEncoder.java
+++ b/src/main/java/net/minecraft/network/PacketEncoder.java
@@ -7,8 +7,17 @@ import io.netty.handler.codec.MessageToByteEncoder;
 import io.netty.util.Attribute;
 import io.netty.util.AttributeKey;
 import java.io.IOException;
+import java.util.Collections;
+
+import net.minecraft.ChatFormatting;
+import net.minecraft.core.NonNullList;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.network.chat.Component;
+import net.minecraft.network.chat.SignedMessageBody;
 import net.minecraft.network.protocol.Packet;
+import net.minecraft.network.protocol.game.*;
 import net.minecraft.util.profiling.jfr.JvmProfiler;
+import net.minecraft.world.item.ItemStack;
 import org.slf4j.Logger;
 
 public class PacketEncoder extends MessageToByteEncoder<Packet<?>> {
@@ -19,6 +28,23 @@ public class PacketEncoder extends MessageToByteEncoder<Packet<?>> {
         this.codecKey = protocolKey;
     }
 
+    // Scissors start
+    private int tryWrite(Packet packet, FriendlyByteBuf friendlyByteBuf, ChannelHandlerContext channelHandlerContext, int i) {
+        friendlyByteBuf.writeVarInt(i);
+        friendlyByteBuf.adventure$locale = channelHandlerContext.channel().attr(io.papermc.paper.adventure.PaperAdventure.LOCALE_ATTRIBUTE).get(); // Paper
+
+        int j = friendlyByteBuf.writerIndex();
+        packet.write(friendlyByteBuf);
+        int k = friendlyByteBuf.writerIndex() - j;
+        int packetLength = friendlyByteBuf.readableBytes();
+        if (packetLength > MAX_PACKET_SIZE) {
+            throw new PacketTooLargeException(packet, this.codecKey, packetLength);
+        }
+
+        return k;
+    }
+    // Scissors end
+
     protected void encode(ChannelHandlerContext channelHandlerContext, Packet<?> packet, ByteBuf byteBuf) throws Exception {
         Attribute<ConnectionProtocol.CodecData<?>> attribute = channelHandlerContext.channel().attr(this.codecKey);
         ConnectionProtocol.CodecData<?> codecData = attribute.get();
@@ -34,46 +60,58 @@ public class PacketEncoder extends MessageToByteEncoder<Packet<?>> {
                 throw new IOException("Can't serialize unregistered packet");
             } else {
                 FriendlyByteBuf friendlyByteBuf = new FriendlyByteBuf(byteBuf);
-                friendlyByteBuf.writeVarInt(i);
-                friendlyByteBuf.adventure$locale = channelHandlerContext.channel().attr(io.papermc.paper.adventure.PaperAdventure.LOCALE_ATTRIBUTE).get(); // Paper - adventure; set player's locale
 
+                // Scissors start
+                int k;
                 try {
-                    int j = friendlyByteBuf.writerIndex();
-                    packet.write(friendlyByteBuf);
-                    int k = friendlyByteBuf.writerIndex() - j;
-                    if (false && k > 8388608) { // Paper - Handle large packets disconnecting client; disable
-                        throw new IllegalArgumentException("Packet too big (is " + k + ", should be less than 8388608): " + packet);
-                    }
-
-                    JvmProfiler.INSTANCE.onPacketSent(codecData.protocol(), i, channelHandlerContext.channel().remoteAddress(), k);
+                    k = this.tryWrite(packet, friendlyByteBuf, channelHandlerContext, i);
                 } catch (Throwable var13) {
-                    // Paper start - Give proper error message
-                    String packetName = io.papermc.paper.util.ObfHelper.INSTANCE.deobfClassName(packet.getClass().getName());
-                    if (packetName.contains(".")) {
-                        packetName = packetName.substring(packetName.lastIndexOf(".") + 1);
-                    }
-
-                    LOGGER.error("Packet encoding of packet {} (ID: {}) threw (skippable? {})", packetName, i, packet.isSkippable(), var13);
-                    // Paper end
-                    if (packet.isSkippable()) {
-                        throw new SkipPacketException(var13);
-                    }
-
-                    throw var13;
-                } finally {
-                    // Paper start - Handle large packets disconnecting client
-                    int packetLength = friendlyByteBuf.readableBytes();
-                    if (packetLength > MAX_PACKET_SIZE) {
-                        throw new PacketTooLargeException(packet, this.codecKey, packetLength);
+                    packet = capPacket(packet, i);
+                    if (packet == null) {
+                        throw new SkipPacketException(new IllegalArgumentException("Packet too big: " + packet));
                     }
-                    // Paper end - Handle large packets disconnecting client
-                    ProtocolSwapHandler.swapProtocolIfNeeded(attribute, packet);
+                    friendlyByteBuf.clear();
+                    k = this.tryWrite(packet, friendlyByteBuf, channelHandlerContext, i);
                 }
-
+                JvmProfiler.INSTANCE.onPacketSent(codecData.protocol(), i, channelHandlerContext.channel().remoteAddress(), k);
+                ProtocolSwapHandler.swapProtocolIfNeeded(attribute, packet);
+                // Scissors end
             }
         }
     }
 
+    // Scissors start
+    private static Packet capPacket(Packet packet, int i) {
+        if (packet instanceof ClientboundBlockEntityDataPacket blockEntityDataPacket) {
+            packet = new ClientboundBlockEntityDataPacket(blockEntityDataPacket.getPos(), blockEntityDataPacket.getType(), new CompoundTag());
+        } else if (packet instanceof ClientboundLevelChunkPacketData chunkPacket) {
+            chunkPacket.clearNBT();
+        } else if (packet instanceof ClientboundContainerSetContentPacket containerSetContentPacket) {
+            packet = new ClientboundContainerSetContentPacket(containerSetContentPacket.getContainerId(), containerSetContentPacket.getStateId(), NonNullList.create(), ItemStack.EMPTY);
+        } else if (packet instanceof ClientboundSetEquipmentPacket setEquipmentPacket) {
+            packet = new ClientboundSetEquipmentPacket(setEquipmentPacket.getEntity(), Collections.emptyList());
+        } else if (packet instanceof ClientboundContainerSetSlotPacket containerSetSlotPacket) {
+            packet = new ClientboundContainerSetSlotPacket(containerSetSlotPacket.getContainerId(), containerSetSlotPacket.getStateId(), containerSetSlotPacket.getSlot(), ItemStack.EMPTY);
+        } else if (packet instanceof ClientboundMapItemDataPacket mapItemDataPacket) {
+            packet = new ClientboundMapItemDataPacket(mapItemDataPacket.getMapId(), mapItemDataPacket.getScale(), mapItemDataPacket.isLocked(), null, null);
+        } else if (packet instanceof ClientboundPlayerChatPacket playerChatPacket) {
+            final SignedMessageBody.Packed body = playerChatPacket.body();
+            packet = new ClientboundPlayerChatPacket(playerChatPacket.sender(), // Not sending this packet results in a kick when someone says something.
+                playerChatPacket.index(),
+                playerChatPacket.signature(),
+                playerChatPacket.body(),
+                Component.empty().append("** Message too large **").withStyle(ChatFormatting.RED),
+                playerChatPacket.filterMask(),
+                playerChatPacket.chatType()
+            );
+        } else {
+            return null;
+        }
+
+        return packet;
+    }
+    // Scissors end
+
     // Paper start
     private static int MAX_PACKET_SIZE = 8388608;
 
diff --git a/src/main/java/net/minecraft/network/protocol/game/ClientboundBlockEntityDataPacket.java b/src/main/java/net/minecraft/network/protocol/game/ClientboundBlockEntityDataPacket.java
index 3944852921335c78a04a9dc301882ab5b152b1ed..96ee53c7cc862e059328c5cdf5e07f309df6a79e 100644
--- a/src/main/java/net/minecraft/network/protocol/game/ClientboundBlockEntityDataPacket.java
+++ b/src/main/java/net/minecraft/network/protocol/game/ClientboundBlockEntityDataPacket.java
@@ -24,7 +24,7 @@ public class ClientboundBlockEntityDataPacket implements Packet<ClientGamePacket
         return create(blockEntity, BlockEntity::getUpdateTag);
     }
 
-    private ClientboundBlockEntityDataPacket(BlockPos pos, BlockEntityType<?> blockEntityType, CompoundTag nbt) {
+    public ClientboundBlockEntityDataPacket(BlockPos pos, BlockEntityType<?> blockEntityType, CompoundTag nbt) { // Scissors - private -> public
         this.pos = pos;
         this.type = blockEntityType;
         this.tag = nbt.isEmpty() ? null : nbt;
diff --git a/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java b/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java
index 998deae645b4497c3285bfba3260c636439f9ecf..f419d4330ea55c1ed91c539a7884ee6814a16ca3 100644
--- a/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java
+++ b/src/main/java/net/minecraft/network/protocol/game/ClientboundLevelChunkPacketData.java
@@ -33,6 +33,13 @@ public class ClientboundLevelChunkPacketData {
     }
     // Paper end - Handle oversized block entities in chunks
 
+    // Scissors start
+    public void clearNBT() {
+        this.blockEntitiesData.clear();
+        this.extraPackets.clear();
+    }
+    // Scissors end
+
     // Paper start - Anti-Xray - Add chunk packet info
     @Deprecated @io.papermc.paper.annotation.DoNotUse public ClientboundLevelChunkPacketData(LevelChunk chunk) { this(chunk, null); }
     public ClientboundLevelChunkPacketData(LevelChunk chunk, com.destroystokyo.paper.antixray.ChunkPacketInfo<net.minecraft.world.level.block.state.BlockState> chunkPacketInfo) {
@@ -58,6 +65,7 @@ public class ClientboundLevelChunkPacketData {
         int totalTileEntities = 0; // Paper - Handle oversized block entities in chunks
 
         for(Map.Entry<BlockPos, BlockEntity> entry2 : chunk.getBlockEntities().entrySet()) {
+            if (this.extraPackets.size() > 50) break; // Scissors - Limit extraPackets size
             // Paper start - Handle oversized block entities in chunks
             if (++totalTileEntities > TE_LIMIT) {
                 var packet = entry2.getValue().getUpdatePacket();