80 lines
4.1 KiB
Diff
80 lines
4.1 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..6bd0afddbcc461149dfe9a5c7a86fff6ea13a5f1
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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 +1,40 @@
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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 org.apache.commons.lang.SystemUtils;
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+
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+import java.io.IOException;
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+import java.io.InputStream;
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+import java.util.Set;
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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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+ boolean isRunningAsRoot = false;
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+ if (new UnixSystem().getUid() == 0) {
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+ // Due to an OpenJDK bug (https://bugs.openjdk.java.net/browse/JDK-8274721), UnixSystem#getUid incorrectly
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+ // returns 0 when the user doesn't have a username. Because of this, we'll have to double-check if the user ID is
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+ // actually 0 by running the id -u command.
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+ try {
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+ Process process = new ProcessBuilder("id", "-u").start();
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+ process.waitFor();
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+ InputStream inputStream = process.getInputStream();
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+ isRunningAsRoot = new String(inputStream.readAllBytes()).trim().equals("0");
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+ } catch (InterruptedException | IOException ignored) {
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+ isRunningAsRoot = false;
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+ }
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+ }
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+ RUNNING_AS_ROOT_OR_ADMIN = isRunningAsRoot;
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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 82cee660a029547eda8abdf4188b9d1fb4ba0d53..38a0fb9a7c4ade9cacfd30dffabfea7e6b773981 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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@@ -188,6 +188,16 @@ 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
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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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