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basic hostname validation

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Shane Freeder 2021-04-18 21:47:01 +01:00
parent 0fb8bdf0e0
commit 23afda1795
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Spigot-Server-Patches/0703-Validate-bungee-forwarded-hostname.patch Normal file
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@ -0,0 +1,54 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Shane Freeder <theboyetronic@gmail.com>
Date: Sun, 18 Apr 2021 21:27:01 +0100
Subject: [PATCH] Validate bungee forwarded hostname
Seriously, fix your firewalls. -.-
diff --git a/src/main/java/net/minecraft/server/network/HandshakeListener.java b/src/main/java/net/minecraft/server/network/HandshakeListener.java
index b97d289afdff81d9959e238639f4e3e186f8e9c8..e13ed3a17866ce3ef0b2ac1dbcb17fb726c89fa8 100644
--- a/src/main/java/net/minecraft/server/network/HandshakeListener.java
+++ b/src/main/java/net/minecraft/server/network/HandshakeListener.java
@@ -1,5 +1,8 @@
package net.minecraft.server.network;
+import com.google.common.net.InetAddresses;
+import com.google.common.net.InternetDomainName;
+
import net.minecraft.SharedConstants;
import net.minecraft.network.EnumProtocol;
import net.minecraft.network.NetworkManager;
@@ -26,6 +29,7 @@ public class HandshakeListener implements PacketHandshakingInListener {
private static final IChatBaseComponent a = new ChatComponentText("Ignoring status request");
private final MinecraftServer b;
private final NetworkManager c; final NetworkManager getNetworkManager() { return this.c; } // Paper - OBFHELPER
+ private static final boolean BYPASS_HOSTCHECK = Boolean.getBoolean("Paper.bypassHostCheck"); // Paper
public HandshakeListener(MinecraftServer minecraftserver, NetworkManager networkmanager) {
this.b = minecraftserver;
@@ -114,6 +118,14 @@ public class HandshakeListener implements PacketHandshakingInListener {
//if (org.spigotmc.SpigotConfig.bungee) { // Paper - comment out, we check above!
String[] split = packethandshakinginsetprotocol.hostname.split("\00");
if ( split.length == 3 || split.length == 4 ) {
+ // Paper start
+ if (!BYPASS_HOSTCHECK && !validate(split[0])) {
+ final ChatMessage message = new ChatMessage("Invalid hostname");
+ this.c.sendPacket(new PacketLoginOutDisconnect(message));
+ this.c.close(message);
+ return;
+ }
+ // Paper end
packethandshakinginsetprotocol.hostname = split[0];
c.socketAddress = new java.net.InetSocketAddress(split[1], ((java.net.InetSocketAddress) c.getSocketAddress()).getPort());
c.spoofedUUID = com.mojang.util.UUIDTypeAdapter.fromString( split[2] );
@@ -158,4 +170,10 @@ public class HandshakeListener implements PacketHandshakingInListener {
public NetworkManager a() {
return this.c;
}
+
+ // Paper start - https://stackoverflow.com/questions/9954140/check-if-a-string-is-a-hostname-or-an-ip-address-in-java
+ public static boolean validate(final String hostname) {
+ //noinspection UnstableApiUsage
+ return InetAddresses.isUriInetAddress(hostname);
+ }
}