From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Nassim Jahnke <nassim@njahnke.dev>
Date: Mon, 11 Sep 2023 12:01:57 +1000
Subject: [PATCH] Add slot sanity checks in container clicks


diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index cabdd17112b130564fb3876c5db711721f13cfba..9073db9ad3627633f46314ae936d584fa400a9ce 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -2983,6 +2983,12 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
                             break;
                         case SWAP:
                             if ((packet.getButtonNum() >= 0 && packet.getButtonNum() < 9) || packet.getButtonNum() == 40) {
+                                // Paper start
+                                if (packet.getSlotNum() < 0) {
+                                    action = InventoryAction.NOTHING;
+                                    break;
+                                }
+                                // Paper end
                                 click = (packet.getButtonNum() == 40) ? ClickType.SWAP_OFFHAND : ClickType.NUMBER_KEY;
                                 Slot clickedSlot = this.player.containerMenu.getSlot(packet.getSlotNum());
                                 if (clickedSlot.mayPickup(this.player)) {
diff --git a/src/main/java/net/minecraft/world/inventory/AbstractContainerMenu.java b/src/main/java/net/minecraft/world/inventory/AbstractContainerMenu.java
index 9ee3c2e0dcfaa4280be4973479c6490ded33809c..cdd230337584befb37f2e48b24dd504398b431a5 100644
--- a/src/main/java/net/minecraft/world/inventory/AbstractContainerMenu.java
+++ b/src/main/java/net/minecraft/world/inventory/AbstractContainerMenu.java
@@ -423,6 +423,7 @@ public abstract class AbstractContainerMenu {
                     this.resetQuickCraft();
                 }
             } else if (this.quickcraftStatus == 1) {
+                if (slotIndex < 0) return; // Paper
                 slot = (Slot) this.slots.get(slotIndex);
                 itemstack = this.getCarried();
                 if (AbstractContainerMenu.canItemQuickReplace(slot, itemstack, true) && slot.mayPlace(itemstack) && (this.quickcraftType == 2 || itemstack.getCount() > this.quickcraftSlots.size()) && this.canDragTo(slot)) {
@@ -597,6 +598,7 @@ public abstract class AbstractContainerMenu {
                 int j2;
 
                 if (actionType == ClickType.SWAP && (button >= 0 && button < 9 || button == 40)) {
+                    if (slotIndex < 0) return; // Paper
                     ItemStack itemstack4 = playerinventory.getItem(button);
 
                     slot = (Slot) this.slots.get(slotIndex);