Re-implement duplicate Magisk Manager logic

Starting from the next Magisk release, it will no longer prefer the package name com.topjohnwu.magisk over a hidden manager; it will always be aware whether the hidden manager exists, so when a package named com.topjohnwu.magisk is installed alongside with the hidden manager, com.topjohnwu.magisk will not have root access by default.
This will prevent malware from using the package name com.topjohnwu.magisk to gain root access when a user is using a hidden manager.
To support this new behavior, several changes has to be done:
- Never grant com.topjohnwu.magisk in Magisk Manager (if it IS the actual manager, MagiskSU will grant it by default)
- While hidden, remove com.topjohnwu.magisk if exists
- Restore Magisk Manager (unhide) has to be done with root
- Upgrading Magisk Manager should preserve package name (implemented in a949641)

src/full/java/com/topjohnwu/magisk/MagiskManager.java

@@ -3,7 +3,6 @@ package com.topjohnwu.magisk;
 import android.app.job.JobInfo;
 import android.app.job.JobScheduler;
 import android.content.ComponentName;
-import android.content.Intent;
 import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.content.res.Configuration;
@@ -131,25 +130,19 @@ public class MagiskManager extends Application implements Shell.Container {
         });
 
         prefs = PreferenceManager.getDefaultSharedPreferences(this);
-
-        // Handle duplicate package
-        if (!getPackageName().equals(Const.ORIG_PKG_NAME)) {
-            try {
-                getPackageManager().getApplicationInfo(Const.ORIG_PKG_NAME, 0);
-                Intent intent = getPackageManager().getLaunchIntentForPackage(Const.ORIG_PKG_NAME);
-                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
-                startActivity(intent);
-                return;
-            } catch (PackageManager.NameNotFoundException ignored) { /* Expected */ }
-        }
-
         mDB = MagiskDatabaseHelper.getInstance(this);
 
-        String pkg = mDB.getStrings(Const.Key.SU_REQUESTER, Const.ORIG_PKG_NAME);
+        String pkg = mDB.getStrings(Const.Key.SU_MANAGER, null);
-        if (getPackageName().equals(Const.ORIG_PKG_NAME) && !pkg.equals(Const.ORIG_PKG_NAME)) {
+        if (pkg != null && getPackageName().equals(Const.ORIG_PKG_NAME)) {
-            mDB.setStrings(Const.Key.SU_REQUESTER, null);
+            mDB.setStrings(Const.Key.SU_MANAGER, null);
             RootUtils.uninstallPkg(pkg);
-            mDB = MagiskDatabaseHelper.getInstance(this);
+        }
+        if (TextUtils.equals(pkg, getPackageName())) {
+            try {
+                // We are the manager, remove com.topjohnwu.magisk as it could be malware
+                getPackageManager().getApplicationInfo(Const.ORIG_PKG_NAME, 0);
+                RootUtils.uninstallPkg(Const.ORIG_PKG_NAME);
+            } catch (PackageManager.NameNotFoundException ignored) {}
         }
 
         setLocale();

src/full/java/com/topjohnwu/magisk/SettingsActivity.java

@@ -1,8 +1,8 @@
 package com.topjohnwu.magisk;
 
-import android.Manifest;
+import android.content.Context;
-import android.content.Intent;
 import android.content.SharedPreferences;
+import android.net.Uri;
 import android.os.Build;
 import android.os.Bundle;
 import android.support.v14.preference.SwitchPreference;
@@ -23,9 +23,10 @@ import android.widget.Toast;
 import com.topjohnwu.magisk.asyncs.CheckUpdates;
 import com.topjohnwu.magisk.asyncs.HideManager;
 import com.topjohnwu.magisk.components.Activity;
-import com.topjohnwu.magisk.receivers.ManagerUpdate;
+import com.topjohnwu.magisk.receivers.DownloadReceiver;
 import com.topjohnwu.magisk.utils.Const;
 import com.topjohnwu.magisk.utils.FingerprintHelper;
+import com.topjohnwu.magisk.utils.RootUtils;
 import com.topjohnwu.magisk.utils.Topic;
 import com.topjohnwu.magisk.utils.Utils;
 import com.topjohnwu.superuser.Shell;
@@ -166,15 +167,18 @@ public class SettingsActivity extends Activity implements Topic.Subscriber {
                 } else {
                     if (Utils.checkNetworkStatus()) {
                         restoreManager.setOnPreferenceClickListener((pref) -> {
-                            runWithPermission(getActivity(),
+                            Utils.dlAndReceive(
-                                    new String[] { Manifest.permission.WRITE_EXTERNAL_STORAGE }, () -> {
+                                getActivity(), new DownloadReceiver() {
-                                        Intent intent = new Intent(mm, ManagerUpdate.class);
+                                    @Override
-                                        intent.putExtra(Const.Key.INTENT_SET_LINK, mm.managerLink);
+                                    public void onDownloadDone(Context context, Uri uri) {
-                                        intent.putExtra(Const.Key.INTENT_SET_FILENAME,
+                                        mm.dumpPrefs();
-                                                Utils.fmt("MagiskManager-v%s(%d).apk",
+                                        if (RootUtils.cmdResult("pm install " + uri.getPath()))
-                                                        mm.remoteManagerVersionString, mm.remoteManagerVersionCode));
+                                            RootUtils.uninstallPkg(context.getPackageName());
-                                        mm.sendBroadcast(intent);
+                                    }
-                                    });
+                                },
+                                mm.managerLink,
+                                Utils.fmt("MagiskManager-v%s.apk", mm.remoteManagerVersionString)
+                            );
                             return true;
                         });
                     } else {

src/full/java/com/topjohnwu/magisk/asyncs/HideManager.java

@@ -77,7 +77,7 @@ public class HideManager extends ParallelTask<Void, Void, Boolean> {
 
         repack.delete();
 
-        mm.mDB.setStrings(Const.Key.SU_REQUESTER, pkg);
+        mm.mDB.setStrings(Const.Key.SU_MANAGER, pkg);
         mm.dumpPrefs();
         RootUtils.uninstallPkg(Const.ORIG_PKG_NAME);
 

src/full/java/com/topjohnwu/magisk/receivers/ManagerUpdate.java

@@ -5,7 +5,6 @@ import android.content.Context;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.AsyncTask;
-import android.os.Handler;
 
 import com.topjohnwu.magisk.utils.Const;
 import com.topjohnwu.magisk.utils.PatchAPK;

src/full/java/com/topjohnwu/magisk/superuser/RequestActivity.java

@@ -277,6 +277,10 @@ public class RequestActivity extends Activity {
                 if (policy == null) {
                     policy = new Policy(uid, pm);
                 }
+
+                /* Never allow com.topjohnwu.magisk (could be malware) */
+                if (TextUtils.equals(policy.packageName, Const.ORIG_PKG_NAME))
+                    return false;
             } catch (Exception e) {
                 e.printStackTrace();
                 return false;

src/main/java/com/topjohnwu/magisk/utils/Const.java

@@ -94,7 +94,7 @@ public class Const {
         public static final String ROOT_ACCESS = "root_access";
         public static final String SU_MULTIUSER_MODE = "multiuser_mode";
         public static final String SU_MNT_NS = "mnt_ns";
-        public static final String SU_REQUESTER = "requester";
+        public static final String SU_MANAGER = "requester";
         public static final String SU_REQUEST_TIMEOUT = "su_request_timeout";
         public static final String SU_AUTO_RESPONSE = "su_auto_response";
         public static final String SU_NOTIFICATION = "su_notification";