From 42f9af57ce765b2623347b5ae71434a3043d4c97 Mon Sep 17 00:00:00 2001
From: Bella <bella.who.two@gmail.com>
Date: Sat, 11 Jan 2020 20:23:18 -0500
Subject: [PATCH] add antichunkload patch

---
 .../client/MixinNettyCompressionDecoder.java  | 67 +++++++++++++++++++
 .../bewwawho/player/AntiChunkLoadPatch.java   | 19 ++++++
 src/main/resources/mixins.kami.json           |  3 +-
 3 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/me/zeroeightsix/kami/mixin/client/MixinNettyCompressionDecoder.java
 create mode 100644 src/main/java/me/zeroeightsix/kami/module/modules/bewwawho/player/AntiChunkLoadPatch.java

diff --git a/src/main/java/me/zeroeightsix/kami/mixin/client/MixinNettyCompressionDecoder.java b/src/main/java/me/zeroeightsix/kami/mixin/client/MixinNettyCompressionDecoder.java
new file mode 100644
index 000000000..1721c7da5
--- /dev/null
+++ b/src/main/java/me/zeroeightsix/kami/mixin/client/MixinNettyCompressionDecoder.java
@@ -0,0 +1,67 @@
+package me.zeroeightsix.kami.mixin.client;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelHandlerContext;
+import me.zeroeightsix.kami.command.Command;
+import me.zeroeightsix.kami.module.modules.bewwawho.player.AntiChunkLoadPatch;
+import net.minecraft.client.Minecraft;
+import net.minecraft.network.NettyCompressionDecoder;
+import net.minecraft.network.PacketBuffer;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+import java.util.List;
+import java.util.zip.DataFormatException;
+import java.util.zip.Inflater;
+
+/**
+ * Created by 0x2E | PretendingToCode on 29/12/19
+ * Updated by S-B99 on 11/01/20
+ */
+@Mixin(NettyCompressionDecoder.class)
+public class MixinNettyCompressionDecoder {
+
+    public int readVarIntFromBuffer(PacketBuffer arg){
+        int i = 0;
+        int j = 0;
+
+        while (true) {
+            byte b0 = arg.readByte();
+            i |= (b0 & 127) << j++ * 7;
+
+            if (j > 5) throw new RuntimeException("VarInt too big");
+            if ((b0 & 128) != 128) break;
+        }
+        return i;
+    }
+
+    @Inject(method = "decode", at = @At("HEAD"), cancellable = true)
+    private void decode(ChannelHandlerContext p_decode_1_, ByteBuf p_decode_2_, List<Object> p_decode_3_, CallbackInfo info) throws DataFormatException {
+        Inflater packetInflater = new Inflater();
+        if (p_decode_2_.readableBytes() != 0 && AntiChunkLoadPatch.enabled()) {
+            PacketBuffer packetbuffer = new PacketBuffer(p_decode_2_);
+            int i = readVarIntFromBuffer(packetbuffer);
+
+            if (i == 0) {
+                p_decode_3_.add(packetbuffer.readBytes(packetbuffer.readableBytes()));
+            }
+            else if (i > 2097152) {
+                if (Minecraft.getMinecraft().player != null) {
+                    Command.sendWarningMessage("&7[&c&lDecoderException&r&7] &rBadly compressed packet - size of " + String.valueOf(i) + " is larger than protocol maximum of 2097152");
+                    Command.sendErrorMessage("&7[&c&lDecoderException&r&7] Not loading chunk due to possible kick");
+                }
+
+                byte[] abyte = new byte[packetbuffer.readableBytes()];
+                packetbuffer.readBytes(abyte);
+                packetInflater.setInput(abyte);
+                byte[] abyte1 = new byte[i];
+                packetInflater.inflate(abyte1);
+                p_decode_3_.add(Unpooled.wrappedBuffer(abyte1));
+                packetInflater.reset();
+            }
+        }
+    }
+}
diff --git a/src/main/java/me/zeroeightsix/kami/module/modules/bewwawho/player/AntiChunkLoadPatch.java b/src/main/java/me/zeroeightsix/kami/module/modules/bewwawho/player/AntiChunkLoadPatch.java
new file mode 100644
index 000000000..56ad55f87
--- /dev/null
+++ b/src/main/java/me/zeroeightsix/kami/module/modules/bewwawho/player/AntiChunkLoadPatch.java
@@ -0,0 +1,19 @@
+package me.zeroeightsix.kami.module.modules.bewwawho.player;
+
+import me.zeroeightsix.kami.module.Module;
+
+/***
+ * Created by S-B99 on 11/01/20
+ */
+@Module.Info(name = "AntiChunkLoadPatch", category = Module.Category.PLAYER, description = "Prevents loading of overloaded chunks", showOnArray = Module.ShowOnArray.OFF)
+public class AntiChunkLoadPatch extends Module {
+    private static AntiChunkLoadPatch INSTANCE = new AntiChunkLoadPatch();
+
+    public AntiChunkLoadPatch() {
+        INSTANCE = this;
+    }
+
+    public static boolean enabled() {
+        return INSTANCE.isEnabled();
+    }
+}
diff --git a/src/main/resources/mixins.kami.json b/src/main/resources/mixins.kami.json
index 41671c29b..ef59a616b 100644
--- a/src/main/resources/mixins.kami.json
+++ b/src/main/resources/mixins.kami.json
@@ -25,6 +25,7 @@
     "MixinStateImplementation",
     "MixinAbstractClientPlayer",
     "MixinGuiNewChat",
-    "MixinLayerBipedArmor"
+    "MixinLayerBipedArmor",
+    "MixinNettyCompressionDecoder"
   ]
 }