RmPerm (with remove ADs feature!)

RmPerm is a command line tool, written in Java, for remove unwanted permissions and/or ADs from an Android APK file. This is done replacing (using dexlib2) the API methods that use certain permissions with custom ones.

You can create your custom methods in this way otherwise you can use my custom one: I created another project for this purpose.

You can download the JAR from here.

I also released an Android app that uses it, it's GUI is disgusting, any help will be appreciated!

Usage

usage: rmperm [-a] [-c <APK/DEX-filename>] [-d] [-h] [-i <APK-filename>]
-l | -r | -ra | -s <Folder-path> [-o <APK-filename>] [-p <CSVpermission names>] [-v]
 -a,--ads                                  Enable ADs removal
 -c,--custom-methods <APK/DEX-filename>    APK/Dex file with custom
                                           classes
 -d,--debug                                Debug output (implies -v)
 -h,--help                                 Print this help
 -i,--input <APK-filename>                 Input APK file
 -l,--list                                 List permissions
 -o,--output <APK-filename>                Output APK filename
 -p,--permissions <CSV permission names>   Permissions to remove
 -r,--remove                               Remove
 -ra,--removeads                           Remove only ads
 -s,--statistics <Folder-path>             Statistics of contained APKs
 -v,--verbose                              Verbose output

N.b.: the square brackets indicate that it is an optional argument.

There are four kinds of scenario:

1. You want to see what permissions are required by the APK:

• --list
• --input file.apk

2. You want to remove certain permissions [and ADs] from the APK:

• --remove
• --input file.apk
• --output output.apk
• --permissions PERM1,PERM2,...,PERMN
• --custom-methods custom.apk | classes.dex
• [--ads]

3. You want to remove only the ADs from the APK:

• --removeads
• --input file.apk
• --output output.apk

4. You want to obtain statistics from a set of APKs stored in the same folder:

• --statistics folder/

How works the permission removal?

Consider a method m invoked on a c instance of type C that returns an object Or of type Tr, invoked with n arguments a1, ..., an respectively of type T1, ..., Tn

Tr Or = c.m(T1 a1, ... , Tn an)

If Tr = void the call can be easily removed, otherwise you have to define a static method (so you don't need an instance for invoke it) with the same name (m in our case) in a class H that returns the same object (Or of type Tr), invoked with n+1 arguments a1, ..., an, an+1 the first of them of type C.

Tr Or = H.m(C c, T1 a1, ... , Tn an)

In this way for remove a permissionis is sufficient to create a class H with all methods of permissions you want to remove.

Example

Probably you have read anything of what I've written, ok I give to you an example with the method isWifiEnabled that use the permission ACCESS_WIFI_STATE:

WifiManager wifi = (WifiManager) getSystemService(Context.WIFI SERVICE);
boolean b = wifi.isWifiEnabled();
if (b) {...}

You define this method (you can find more of them here):

@CustomMethodClass
public class CustomMethods {
    @MethodPermission(permission = "android.permission.ACCESS_WIFI_STATE", defClass ="android.net.wifi.WifiManager")
    public static boolean isWifiEnabled(WifiManager wm) {
        return false;
    }
}

Here I do something simple but you can instrument, log, hack, crack, trick, track... do what you want!

Finally RmPerm transform it into:

WifiManager wifi = (WifiManager) getSystemService(Context.WIFI SERVICE);
boolean b = CustomMethods.isWifiEnabled(wifi);

How works the ADs removal?

All classes like AdView and PublisherAdView implement the loadAd(...) method.

If this method isn't called the View doesn't load the AD, so, very simply:

• every time that I found a method called loadAd

• that is defined in a class belonging to com.google.android.gms.ads.

• and its return type is void

I remove it :)