Paper/Spigot-Server-Patches/0495-Validate-PickItem-Packet-and-kick-for-invalid.patch
Aikar 614a664bd3
Implement Chunk Priority / Urgency System for Chunks
Mark chunks that are blocking main thread for world generation as urgent

Implements a general priority system so that chunks that are sorted in
the generator queues can prioritize certain chunks over another.

Urgent chunks will jump to the front of the line, ensuring that a
sync chunk load on an ungenerated chunk does not lag the server for
a long period of time if the servers generator queues are filled with
lots of chunks already.

This massively reduces the lag spikes from sync chunk gens.

Then we further prioritize loading order so nearby chunks have higher
priority than distant chunks, reducing the pressure a high no tick
view distance holds on you.

Chunks in front of the player have higher priority, to help with
fast traveling players keep up with their movement.

This commit also improves single core cpu scenarios in that we will
now automatically disable Async Chunks as well as Minecrafts thread
pool.

It is never recommended to use async chunks on a single CPU as context
switching will be slower than just running it all on main.

This also bumps the number of server worker threads by default too.
Mojang does not utilize the workers in an effecient manner, resulting
in them using barely any sustained CPU.

So give it more workers so more chunks can be processed concurrently

This change also improves urgent chunk loading, so players flying into
unloaded chunks will hurt a little bit less (but still hurt)

Ping #3395 #3363 (Not marking as closed, we need to make prevent moving work)
2020-05-19 04:09:37 -04:00

27 lines
1.8 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sat, 2 May 2020 03:09:46 -0400
Subject: [PATCH] Validate PickItem Packet and kick for invalid
diff --git a/src/main/java/net/minecraft/server/PlayerConnection.java b/src/main/java/net/minecraft/server/PlayerConnection.java
index 63cbdc3531712b9b63f75789c3481a74a44a0fa7..625479b97adf19df67f04dcbe445d78bccb0fc2c 100644
--- a/src/main/java/net/minecraft/server/PlayerConnection.java
+++ b/src/main/java/net/minecraft/server/PlayerConnection.java
@@ -696,7 +696,14 @@ public class PlayerConnection implements PacketListenerPlayIn {
@Override
public void a(PacketPlayInPickItem packetplayinpickitem) {
PlayerConnectionUtils.ensureMainThread(packetplayinpickitem, this, this.player.getWorldServer());
- this.player.inventory.c(packetplayinpickitem.b());
+ // Paper start - validate pick item position
+ if (!(packetplayinpickitem.b() >= 0 && packetplayinpickitem.b() < this.player.inventory.items.size())) {
+ PlayerConnection.LOGGER.warn("{} tried to set an invalid carried item", this.player.getDisplayName().getString());
+ this.disconnect("Invalid hotbar selection (Hacking?)");
+ return;
+ }
+ this.player.inventory.c(packetplayinpickitem.b()); // Paper - Diff above if changed
+ // Paper end
this.player.playerConnection.sendPacket(new PacketPlayOutSetSlot(-2, this.player.inventory.itemInHandIndex, this.player.inventory.getItem(this.player.inventory.itemInHandIndex)));
this.player.playerConnection.sendPacket(new PacketPlayOutSetSlot(-2, packetplayinpickitem.b(), this.player.inventory.getItem(packetplayinpickitem.b())));
this.player.playerConnection.sendPacket(new PacketPlayOutHeldItemSlot(this.player.inventory.itemInHandIndex));