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c5a10665b8
Spigot still maintains some partial implementation of "tick skipping", a practice in which the MinecraftServer.currentTick field is updated not by an increment of one per actual tick, but instead set to System.currentTimeMillis() / 50. This behaviour means that the tracked tick may "skip" a tick value in case a previous tick took more than the expected 50ms. To compensate for this in important paths, spigot/craftbukkit implements "wall-time". Instead of incrementing/decrementing ticks on block entities/entities by one for each call to their tick() method, they instead increment/decrement important values, like an ItemEntity's age or pickupDelay, by the difference of `currentTick - lastTick`, where `lastTick` is the value of `currentTick` during the last tick() call. These "fixes" however do not play nicely with minecraft's simulation distance as entities/block entities implementing the above behaviour would "catch up" their values when moving from a non-ticking chunk to a ticking one as their `lastTick` value remains stuck on the last tick in a ticking chunk and hence lead to a large "catch up" once ticked again. Paper completely removes the "tick skipping" behaviour (See patch "Further-improve-server-tick-loop"), making the above precautions completely unnecessary, which also rids paper of the previous described incompatibility with non-ticking chunks.
63 lines
3.2 KiB
Diff
63 lines
3.2 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: egg82 <eggys82@gmail.com>
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Date: Sat, 11 Sep 2021 22:55:14 +0200
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Subject: [PATCH] Add root/admin user detection
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This patch detects whether or not the server is currently executing as a privileged user and spits out a warning.
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The warning serves as a sort-of PSA for newer server admins who don't understand the risks of running as root.
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We've seen plenty of bad/malicious plugins hit markets, and there's been a few close-calls with exploits in the past.
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Hopefully this helps mitigate some potential damage to servers, even if it is just a warning.
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Co-authored-by: Noah van der Aa <ndvdaa@gmail.com>
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diff --git a/src/main/java/io/papermc/paper/util/ServerEnvironment.java b/src/main/java/io/papermc/paper/util/ServerEnvironment.java
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new file mode 100644
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index 0000000000000000000000000000000000000000..68098dfe716e93aafcca4d8d5b5a81d8648b3654
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--- /dev/null
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+++ b/src/main/java/io/papermc/paper/util/ServerEnvironment.java
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@@ -0,0 +1,23 @@
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+package io.papermc.paper.util;
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+
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+import com.sun.security.auth.module.NTSystem;
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+import com.sun.security.auth.module.UnixSystem;
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+import java.util.Set;
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+import org.apache.commons.lang.SystemUtils;
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+
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+public class ServerEnvironment {
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+ private static final boolean RUNNING_AS_ROOT_OR_ADMIN;
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+ private static final String WINDOWS_HIGH_INTEGRITY_LEVEL = "S-1-16-12288";
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+
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+ static {
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+ if (SystemUtils.IS_OS_WINDOWS) {
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+ RUNNING_AS_ROOT_OR_ADMIN = Set.of(new NTSystem().getGroupIDs()).contains(WINDOWS_HIGH_INTEGRITY_LEVEL);
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+ } else {
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+ RUNNING_AS_ROOT_OR_ADMIN = new UnixSystem().getUid() == 0;
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+ }
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+ }
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+
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+ public static boolean userIsRootOrAdmin() {
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+ return RUNNING_AS_ROOT_OR_ADMIN;
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+ }
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+}
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diff --git a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
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index adbd61c41cc30afa89c6ee3544c562b351304a01..585d3e51b4af87327fc2bc64a49f09732a8c61ab 100644
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--- a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
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+++ b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
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@@ -196,6 +196,16 @@ public class DedicatedServer extends MinecraftServer implements ServerInterface
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DedicatedServer.LOGGER.warn("To start the server with more ram, launch it as \"java -Xmx1024M -Xms1024M -jar minecraft_server.jar\"");
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}
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+ // Paper start - detect running as root
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+ if (io.papermc.paper.util.ServerEnvironment.userIsRootOrAdmin()) {
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+ DedicatedServer.LOGGER.warn("****************************");
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+ DedicatedServer.LOGGER.warn("YOU ARE RUNNING THIS SERVER AS AN ADMINISTRATIVE OR ROOT USER. THIS IS NOT ADVISED.");
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+ DedicatedServer.LOGGER.warn("YOU ARE OPENING YOURSELF UP TO POTENTIAL RISKS WHEN DOING THIS.");
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+ DedicatedServer.LOGGER.warn("FOR MORE INFORMATION, SEE https://madelinemiller.dev/blog/root-minecraft-server/");
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+ DedicatedServer.LOGGER.warn("****************************");
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+ }
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+ // Paper end - detect running as root
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+
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DedicatedServer.LOGGER.info("Loading properties");
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DedicatedServerProperties dedicatedserverproperties = this.settings.getProperties();
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