PaperMC/patches/server/0179-Make-legacy-ping-handler-more-reliable.patch
Nassim Jahnke 31699ae9a8
Updated Upstream (Bukkit/CraftBukkit) (#10242)
* Updated Upstream (Bukkit/CraftBukkit)

Upstream has released updates that appear to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing

Bukkit Changes:
a6a9d2a4 Remove some old ApiStatus.Experimental annotations
be72314c SPIGOT-7300, PR-829: Add new DamageSource API providing enhanced information about entity damage
b252cf05 SPIGOT-7576, PR-970: Add methods in MushroomCow to change stew effects
b1c689bd PR-902: Add Server#isLoggingIPs to get log-ips configuration
08f86d1c PR-971: Add Player methods for client-side potion effects
2e3024a9 PR-963: Add API for in-world structures
a23292a7 SPIGOT-7530, PR-948: Improve Resource Pack API with new 1.20.3 functionality
1851857b SPIGOT-3071, PR-969: Add entity spawn method with spawn reason
cde4c52a SPIGOT-5553, PR-964: Add EntityKnockbackEvent

CraftBukkit Changes:
38fd4bd50 Fix accidentally renamed internal damage method
80f0ce4be SPIGOT-7300, PR-1180: Add new DamageSource API providing enhanced information about entity damage
7e43f3b16 SPIGOT-7581: Fix typo in BlockMushroom
ea14b7d90 SPIGOT-7576, PR-1347: Add methods in MushroomCow to change stew effects
4c687f243 PR-1259: Add Server#isLoggingIPs to get log-ips configuration
22a541a29 Improve support for per-world game rules
cb7dccce2 PR-1348: Add Player methods for client-side potion effects
b8d6109f0 PR-1335: Add API for in-world structures
4398a1b5b SPIGOT-7577: Make CraftWindCharge#explode discard the entity
e74107678 Fix Crafter maximum stack size
0bb0f4f6a SPIGOT-7530, PR-1314: Improve Resource Pack API with new 1.20.3 functionality
4949f556d SPIGOT-3071, PR-1345: Add entity spawn method with spawn reason
20ac73ca2 PR-1353: Fix Structure#place not working as documented with 0 palette
3c1b77871 SPIGOT-6911, PR-1349: Change max book length in CraftMetaBook
333701839 SPIGOT-7572: Bee nests generated without bees
f48f4174c SPIGOT-5553, PR-1336: Add EntityKnockbackEvent
2024-02-11 22:28:00 +01:00

188 lines
7.6 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Minecrell <minecrell@minecrell.net>
Date: Wed, 11 Oct 2017 18:22:50 +0200
Subject: [PATCH] Make legacy ping handler more reliable
The Minecraft server often fails to respond to old ("legacy") pings
from old Minecraft versions using the protocol used before the switch
to Netty in Minecraft 1.7.
Due to packet fragmentation[1], we might not have all needed bytes
available when the LegacyPingHandler is called. In this case, it will
run into an error, remove the handler and continue using the modern
protocol.
This is unlikely to happen for the first two revisions of the legacy
ping protocol (used in Minecraft 1.5.x and older) since the request
consists of only one or two bytes, but happens frequently for the
last/third revision introduced in Minecraft 1.6.
It has much larger, variable packet sizes due to the inclusion of
the virtual host (the hostname/port used to connect to the server).
The solution[2] is simple: If we find more than two matching bytes,
we buffer the remaining bytes until we have enough to fully read and
respond to the request.
[1]: https://netty.io/wiki/user-guide-for-4.x.html#wiki-h3-11
[2]: https://netty.io/wiki/user-guide-for-4.x.html#wiki-h4-13
diff --git a/src/main/java/net/minecraft/server/network/LegacyQueryHandler.java b/src/main/java/net/minecraft/server/network/LegacyQueryHandler.java
index 33e3a81f8ec18f0ba7170d885c4717640bf40eab..738da83f82bf01bde94c956ac22525a638db3906 100644
--- a/src/main/java/net/minecraft/server/network/LegacyQueryHandler.java
+++ b/src/main/java/net/minecraft/server/network/LegacyQueryHandler.java
@@ -15,6 +15,7 @@ public class LegacyQueryHandler extends ChannelInboundHandlerAdapter {
private static final Logger LOGGER = LogUtils.getLogger();
private final ServerInfo server;
+ private ByteBuf buf; // Paper
public LegacyQueryHandler(ServerInfo server) {
this.server = server;
@@ -23,6 +24,16 @@ public class LegacyQueryHandler extends ChannelInboundHandlerAdapter {
public void channelRead(ChannelHandlerContext channelhandlercontext, Object object) {
ByteBuf bytebuf = (ByteBuf) object;
+ // Paper start - Make legacy ping handler more reliable
+ if (this.buf != null) {
+ try {
+ readLegacy1_6(channelhandlercontext, bytebuf);
+ } finally {
+ bytebuf.release();
+ }
+ return;
+ }
+ // Paper end
bytebuf.markReaderIndex();
boolean flag = true;
@@ -34,7 +45,7 @@ public class LegacyQueryHandler extends ChannelInboundHandlerAdapter {
SocketAddress socketaddress = channelhandlercontext.channel().remoteAddress();
int i = bytebuf.readableBytes();
- String s;
+ String s = null; // Paper
org.bukkit.event.server.ServerListPingEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callServerListPingEvent(socketaddress, this.server.getMotd(), this.server.getPlayerCount(), this.server.getMaxPlayers()); // CraftBukkit
if (i == 0) {
@@ -47,16 +58,24 @@ public class LegacyQueryHandler extends ChannelInboundHandlerAdapter {
}
if (bytebuf.isReadable()) {
- if (!LegacyQueryHandler.readCustomPayloadPacket(bytebuf)) {
- return;
+ // Paper start - Replace with improved version below
+ if (bytebuf.readUnsignedByte() != 250) {
+ s = this.readLegacy1_6(channelhandlercontext, bytebuf);
+ if (s == null) {
+ return;
+ }
}
-
- LegacyQueryHandler.LOGGER.debug("Ping: (1.6) from {}", socketaddress);
+ // if (!LegacyQueryHandler.readCustomPayloadPacket(bytebuf)) {
+ // return;
+ // }
+ //
+ // LegacyQueryHandler.LOGGER.debug("Ping: (1.6) from {}", socketaddress);
+ // Paper end
} else {
LegacyQueryHandler.LOGGER.debug("Ping: (1.4-1.5.x) from {}", socketaddress);
}
- s = LegacyQueryHandler.createVersion1Response(this.server, event); // CraftBukkit
+ if (s == null) s = LegacyQueryHandler.createVersion1Response(this.server, event); // CraftBukkit // Paper
LegacyQueryHandler.sendFlushAndClose(channelhandlercontext, LegacyQueryHandler.createLegacyDisconnectPacket(channelhandlercontext.alloc(), s));
}
@@ -107,6 +126,90 @@ public class LegacyQueryHandler extends ChannelInboundHandlerAdapter {
}
}
+ // Paper start
+ private static String readLegacyString(ByteBuf buf) {
+ int size = buf.readShort() * Character.BYTES;
+ if (!buf.isReadable(size)) {
+ return null;
+ }
+
+ String result = buf.toString(buf.readerIndex(), size, java.nio.charset.StandardCharsets.UTF_16BE);
+ buf.skipBytes(size); // toString doesn't increase readerIndex automatically
+ return result;
+ }
+
+ private String readLegacy1_6(ChannelHandlerContext ctx, ByteBuf part) {
+ ByteBuf buf = this.buf;
+
+ if (buf == null) {
+ this.buf = buf = ctx.alloc().buffer();
+ buf.markReaderIndex();
+ } else {
+ buf.resetReaderIndex();
+ }
+
+ buf.writeBytes(part);
+
+ if (!buf.isReadable(Short.BYTES + Short.BYTES + Byte.BYTES + Short.BYTES + Integer.BYTES)) {
+ return null;
+ }
+
+ String s = readLegacyString(buf);
+ if (s == null) {
+ return null;
+ }
+
+ if (!s.equals("MC|PingHost")) {
+ removeHandler(ctx);
+ return null;
+ }
+
+ if (!buf.isReadable(Short.BYTES) || !buf.isReadable(buf.readShort())) {
+ return null;
+ }
+
+ net.minecraft.server.MinecraftServer server = net.minecraft.server.MinecraftServer.getServer();
+ int protocolVersion = buf.readByte();
+ String host = readLegacyString(buf);
+ if (host == null) {
+ removeHandler(ctx);
+ return null;
+ }
+ int port = buf.readInt();
+
+ if (buf.isReadable()) {
+ removeHandler(ctx);
+ return null;
+ }
+
+ buf.release();
+ this.buf = null;
+
+ LOGGER.debug("Ping: (1.6) from {}", ctx.channel().remoteAddress());
+
+ String response = String.format("\u00a71\u0000%d\u0000%s\u0000%s\u0000%d\u0000%d",
+ Byte.MAX_VALUE, server.getServerVersion(), server.getMotd(), server.getPlayerCount(), server.getMaxPlayers());
+ return response;
+ }
+
+ private void removeHandler(ChannelHandlerContext ctx) {
+ ByteBuf buf = this.buf;
+ this.buf = null;
+
+ buf.resetReaderIndex();
+ ctx.pipeline().remove(this);
+ ctx.fireChannelRead(buf);
+ }
+
+ @Override
+ public void handlerRemoved(ChannelHandlerContext ctx) {
+ if (this.buf != null) {
+ this.buf.release();
+ this.buf = null;
+ }
+ }
+ // Paper end
+
// CraftBukkit start
private static String createVersion0Response(ServerInfo serverinfo, org.bukkit.event.server.ServerListPingEvent event) {
return String.format(Locale.ROOT, "%s\u00a7%d\u00a7%d", event.getMotd(), event.getNumPlayers(), event.getMaxPlayers());