From 0952d57b25738151a17baef23d393ed7f4356861 Mon Sep 17 00:00:00 2001
From: Shane Freeder <theboyetronic@gmail.com>
Date: Sun, 15 Oct 2023 00:36:38 +0100
Subject: [PATCH] Prevent proxy commands from breaking the chat chain system


diff --git a/protocol/src/main/java/net/md_5/bungee/protocol/AbstractPacketHandler.java b/protocol/src/main/java/net/md_5/bungee/protocol/AbstractPacketHandler.java
index e2221010..4dde7257 100644
--- a/protocol/src/main/java/net/md_5/bungee/protocol/AbstractPacketHandler.java
+++ b/protocol/src/main/java/net/md_5/bungee/protocol/AbstractPacketHandler.java
@@ -287,5 +287,9 @@ public abstract class AbstractPacketHandler
     public void handle(net.md_5.bungee.protocol.packet.EntityRemoveEffect removeEffect) throws Exception
     {
     }
+
+    public void handle(net.md_5.bungee.protocol.packet.ClientChatAcknowledgement clientChatAcknowledgement)
+    {
+    }
     // Waterfall end
 }
diff --git a/protocol/src/main/java/net/md_5/bungee/protocol/Protocol.java b/protocol/src/main/java/net/md_5/bungee/protocol/Protocol.java
index b0473509..f25d3fab 100644
--- a/protocol/src/main/java/net/md_5/bungee/protocol/Protocol.java
+++ b/protocol/src/main/java/net/md_5/bungee/protocol/Protocol.java
@@ -558,6 +558,13 @@ public enum Protocol
                     map( ProtocolConstants.MINECRAFT_1_19_1, 0x05 ),
                     map( ProtocolConstants.MINECRAFT_1_20_5, 0x06 )
             );
+            // Waterfall start
+            TO_SERVER.registerPacket(
+                    net.md_5.bungee.protocol.packet.ClientChatAcknowledgement.class,
+                    net.md_5.bungee.protocol.packet.ClientChatAcknowledgement::new,
+                    map (ProtocolConstants.MINECRAFT_1_19_3, 0x3)
+            );
+            // Waterfall end
             TO_SERVER.registerPacket(
                     TabCompleteRequest.class,
                     TabCompleteRequest::new,
diff --git a/protocol/src/main/java/net/md_5/bungee/protocol/packet/ClientChatAcknowledgement.java b/protocol/src/main/java/net/md_5/bungee/protocol/packet/ClientChatAcknowledgement.java
new file mode 100644
index 00000000..08ecf2a3
--- /dev/null
+++ b/protocol/src/main/java/net/md_5/bungee/protocol/packet/ClientChatAcknowledgement.java
@@ -0,0 +1,33 @@
+package net.md_5.bungee.protocol.packet;
+
+import io.netty.buffer.ByteBuf;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.NoArgsConstructor;
+import net.md_5.bungee.protocol.AbstractPacketHandler;
+import net.md_5.bungee.protocol.DefinedPacket;
+import net.md_5.bungee.protocol.ProtocolConstants;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+@EqualsAndHashCode(callSuper = false)
+public class ClientChatAcknowledgement extends DefinedPacket  {
+    private int offset;
+
+    @Override
+    public void read(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        this.offset = DefinedPacket.readVarInt(buf);
+    }
+
+    @Override
+    public void write(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        DefinedPacket.writeVarInt(this.offset, buf);
+    }
+
+    @Override
+    public void handle(AbstractPacketHandler handler) throws Exception {
+        handler.handle(this);
+    }
+}
diff --git a/protocol/src/main/java/net/md_5/bungee/protocol/packet/ClientCommand.java b/protocol/src/main/java/net/md_5/bungee/protocol/packet/ClientCommand.java
index 887ff29f..d4700090 100644
--- a/protocol/src/main/java/net/md_5/bungee/protocol/packet/ClientCommand.java
+++ b/protocol/src/main/java/net/md_5/bungee/protocol/packet/ClientCommand.java
@@ -108,4 +108,9 @@ public class ClientCommand extends DefinedPacket
     {
         handler.handle( this );
     }
+
+    public boolean isSigned() {
+        if (salt == 0) return false;
+        return this.seenMessages != null && !this.seenMessages.getAcknowledged().isEmpty();
+    }
 }
diff --git a/proxy/src/main/java/net/md_5/bungee/connection/UpstreamBridge.java b/proxy/src/main/java/net/md_5/bungee/connection/UpstreamBridge.java
index 2dafa4d9..b482fe2e 100644
--- a/proxy/src/main/java/net/md_5/bungee/connection/UpstreamBridge.java
+++ b/proxy/src/main/java/net/md_5/bungee/connection/UpstreamBridge.java
@@ -196,16 +196,22 @@ public class UpstreamBridge extends PacketHandler
     @Override
     public void handle(ClientCommand command) throws Exception
     {
-        handleChat( "/" + command.getCommand() );
+        handleChat( "/" + command.getCommand(), command );
     }
 
     @Override
     public void handle(UnsignedClientCommand command) throws Exception
     {
-        handleChat( "/" + command.getCommand() );
+        handleChat( "/" + command.getCommand(), null); // Waterfall
     }
 
     private String handleChat(String message)
+    {
+        // Waterfall start
+        return handleChat(message, null);
+    }
+    private String handleChat(String message, @javax.annotation.Nullable ClientCommand clientCommand)
+    // Waterfall end
     {
         for ( int index = 0, length = message.length(); index < length; index++ )
         {
@@ -224,7 +230,13 @@ public class UpstreamBridge extends PacketHandler
             if ( !chatEvent.isCommand() || !bungee.getPluginManager().dispatchCommand( con, message.substring( 1 ) ) )
             {
                 return message;
+                // Waterfall start - We're going to cancel this packet, so, no matter what, we might as well try to send this
+            } else if (clientCommand != null && clientCommand.isSigned() && clientCommand.getSeenMessages() != null) {
+                if (con.getPendingConnection().getVersion() >= ProtocolConstants.MINECRAFT_1_19_3) {
+                    con.getServer().unsafe().sendPacket(new net.md_5.bungee.protocol.packet.ClientChatAcknowledgement(clientCommand.getSeenMessages().getOffset()));
+                }
             }
+            // Waterfall end
         }
         throw CancelSendSignal.INSTANCE;
     }
-- 
2.45.1