Protect system services with DUMP permission.

Change-Id: I5e53859f8b8e5473e54eca43ebd7de841f1a05ff
diff --git a/services/java/com/android/server/DiskStatsService.java b/services/java/com/android/server/DiskStatsService.java
index 8ef974a..ac25dc5 100644
--- a/services/java/com/android/server/DiskStatsService.java
+++ b/services/java/com/android/server/DiskStatsService.java
@@ -34,6 +34,8 @@
  * statistics about the status of the disk.
  */
 public class DiskStatsService extends Binder {
+    private static final String TAG = "DiskStatsService";
+
     private final Context mContext;
 
     public DiskStatsService(Context context) {
@@ -42,7 +44,7 @@
 
     @Override
     protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
-        // This data is accessible to any app -- no permission check needed.
+        mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DUMP, TAG);
 
         // Run a quick-and-dirty performance test: write 512 bytes
         byte[] junk = new byte[512];