Configuration of Shielding Tool rules

You can specify a rules list in the App Shielding configuration. This list determines how App Shielding will modify the Android application, especially with regards to shielding and obfuscation.

Find below information about how the rules list can be used to match classes, fields, and methods to resolve issues with shielding or obfuscation.

Syntax

class_op+ [[!]@annotation] [[!]access] [[!]flag]* [[!]class_spec] class_name 
[[!]extension class_name] (; | { 
  [member_op]* [[!]@annotation] [[!]access] [[!]flag]* [member_type] 

})

You can specify as many rules as needed, and the rules are matched from top to bottom.

When configuring rules, you can use one line per rule, or, for better readability, you can use multiple lines for one rule.

 

# Comment
class_operation [[!]access] [!]class_spec class_name [[!]extension class_name] (; | {
[[!]access] [[!]class_mod] member type name;
})
set_operation name value;
firstdex class_name;
verify regex;

Definitions

The following tables list the commands to be used in a rules list.

class_operation options

member_operation options

Class and member definitions

Specification

Negating

For the rules, most class specifiers can be negated by adding an exclamation mark in front of them.

Wildcards

Wildcards can be used as follows:

• * matches zero or more characters.

• + matches one or more characters.

• ? matches exactly one character.

*Test matches MyTestOne and Test but not TestTwo.

Comments

Comments are prefixed with #.

 

# Verify a single file
verify "assets/my-asset.bin";

# Verify all files in the assets folder
verify "^assets/.*";

# Verify all HTML/JS in the assets folder
verify "^assets/(.+)\.(html|js)$";

# Verify all files inside the APK
verify ".*";

Rule examples

Class-level rule

• No values from MyClass will be removed:

  untouchable class com.example.MyClass;

• No values from any class inside the com.example.* package will be removed:

  untouchable class com.example.*;

• No class that implements MyInterface will be modified:

  untouchable class * implements com.example.MyInterface;

• No class that (immediately) derives from MyBaseClass will be modified:

  untouchable class * extends com.example.MyBaseClass;

Method-level rule

• This rule only matches the public static method getValue that returns int within MyClass:

  untouchable class com.example.MyClass
  {
    public static method int getValue;
  }

• This method matches any public method called getValue and setValue in any class that implements SomeInterface. All other methods in these classes can still be modified:

  untouchable class * implements SomeInterface
  {
    public method * getValue;
    public method void setValue;
  }

• To match a constructor, it must be added as a regular method <init> with a void return value:

  untouchable class com.example.MyClass
  {
    public method void <init>;
  }