Store the original SHA-256 inside server jars.

Author: Fox2Code

loader/src/main/java/com/fox2code/foxloader/installer/InstallerGUI.java

@@ -366,6 +366,10 @@ public void extractServer() {
                                     "com.fox2code.foxloader.launcher.ServerMain")
                             .getBytes(StandardCharsets.UTF_8)), zipOutputStream);
                     zipOutputStream.closeEntry();
+                    // Insert the original FoxLoader jar hash in the server jar file.
+                    zipOutputStream.putNextEntry(new ZipEntry("META-INF/FL-SHA-256"));
+                    zipOutputStream.write(IOUtils.sha256Of(Main.currentInstallerFile));
+                    zipOutputStream.closeEntry();
                 } else {
                     zipOutputStream.putNextEntry(zipEntry);
                     IOUtils.copy(zipInputStream, zipOutputStream);

loader/src/main/java/com/fox2code/foxloader/installer/Main.java

@@ -23,6 +23,7 @@
  */
 package com.fox2code.foxloader.installer;
 
+import com.fox2code.foxloader.launcher.FoxLauncher;
 import com.fox2code.foxloader.launcher.LauncherType;
 import com.fox2code.foxloader.launcher.ServerMain;
 import com.fox2code.foxloader.utils.SourceUtil;
@@ -37,6 +38,10 @@
 public class Main {
     static final File currentInstallerFile = SourceUtil.getSourceFile(Main.class);
     public static void main(String[] args) throws Throwable {
+        if (FoxLauncher.class.getClassLoader().getResource("META-INF/FL-SHA-256") != null) {
+            System.out.println("This jar file has been erroneously tampered with!");
+            return;
+        }
         if (args.length == 0 && GraphicsEnvironment.isHeadless()) {
             ServerMain.main(new String[]{"nogui"});
             return;

loader/src/main/java/com/fox2code/foxloader/loader/ModLoaderInit.java

@@ -36,6 +36,7 @@
 import com.fox2code.foxloader.patching.mixin.MixinModLoader;
 import com.fox2code.foxloader.updater.FoxLoaderUpdater;
 import com.fox2code.foxloader.utils.Platform;
+import com.fox2code.foxloader.utils.io.IOUtils;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import net.minecraft.client.Minecraft;
@@ -46,6 +47,8 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
+import java.math.BigInteger;
 import java.util.*;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
@@ -65,6 +68,8 @@ public final class ModLoaderInit {
     static final File config = new File(FoxLauncher.getGameDir(), "config");
     static final ModContainer FOX_LOADER_CONTAINER = new ModContainer(
             JavaLoadingPlugin.JAVA_LOADING_PLUGIN, JavaModInfo.FOX_LOADER_MOD_INFO);
+    // When extracting the server jar, the FoxLoader SHA-256 is altered.
+    public static final String FOXLOADER_TRUE_SHA_256;
     static final LinkedHashMap<String, ModContainer> modContainers = new LinkedHashMap<>();
     private static final Collection<ModContainer> modContainnersCollection =
             Collections.unmodifiableCollection(modContainers.values());
@@ -75,6 +80,16 @@ public final class ModLoaderInit {
         ((LoadingPlugin) JavaLoadingPlugin.JAVA_LOADING_PLUGIN).javaModInfo = JavaModInfo.FOX_LOADER_MOD_INFO;
         FoxLauncher.getFoxClassLoader().injectMissingFileInfo(JavaModInfo.FOX_LOADER_MOD_INFO);
         assertValidModInfo(JavaModInfo.FOX_LOADER_MOD_INFO, true);
+        String trueSha256 = JavaModInfo.FOX_LOADER_MOD_INFO.sha256;
+        try (InputStream inputStream = FoxLauncher.class.getClassLoader().getResourceAsStream("META-INF/FL-SHA-256")) {
+            if (inputStream != null) {
+                if (FoxLauncher.isClient()) {
+                    throw new RuntimeException("This jar file has been erroneously tampered with.");
+                }
+                trueSha256 = new BigInteger(1, IOUtils.readAllBytes(inputStream)).toString(16);
+            }
+        } catch (IOException ignored) {}
+        FOXLOADER_TRUE_SHA_256 = trueSha256;
     }
 
     public static @NotNull Logger getModLoaderLogger() {