Native hook for LSPosed
Budget: $10 – $30 USD
Technical Specification for Developing a Native Hook Module for LSPosed
1. Introduction
The module is designed to operate within the LSPosed environment (an Xposed framework) that supports modifying system and user applications on Android devices. The goal is to create a native (C/C++) module for LSPosed capable of intercepting system method calls and functions, as well as altering their behavior.
2. Development Goals
Develop a module based on native code (C/C++).
Provide integration with LSPosed to intercept Java/ART (Android Runtime) functions and system libraries (via JNI).
Enable modification of the behavior of intercepted functions.
Support devices running Android 8.0 and above.
3. Main Requirements
3.1. Functional Requirements
Integration with LSPosed and module registration.
Interception of Java method calls via ART:
Specific classes/methods (e.g., android.location.LocationManager or java.lang.System).
Universal Java methods filtered by signatures.
Interception of native function calls from system libraries (e.g., via libc or libart.so).
Logging of calls and passed arguments.
Ability to modify return values.
3.2. Non-Functional Requirements
High performance with minimal system load.
Compatibility with LSPosed on Android 8.0+.
Minimal APK size with optimized native code usage.
4. Architecture
4.1. General Structure
Java Layer:
Interaction with LSPosed through the Java API.
Loading and initialization of the native library.
Interface for data transfer between Java and native code.
Native Layer:
Core library in C/C++.
Use of dlopen and dlsym for call interception.
Hooks via art::JNIEnv and ART native classes.
4.2. Tools and Libraries
Android NDK for native code development.
Hook Libraries (e.g., AndHook or frida-gum).
LSPosed API for integration.
5. Technical Details
5.1. Connecting to LSPosed
Register the module in AndroidManifest.xml with LSPosed API specification.
Create a Java class for interaction with LSPosed:
java
Копировать код
public class HookEntry implements IXposedHookLoadPackage {
@Override
public void handleLoadPackage(final LoadPackageParam lpparam) throws Throwable {
System.loadLibrary("native_hook");
NativeHook.init(lpparam.packageName);
}
}
5.2. Java Method Interception
Use ART API to locate and modify methods:
Obtain jclass via FindClass.
Obtain methods via GetMethodID/GetStaticMethodID.
Replace methods using art::Method.
5.3. Native Function Interception
Use dlopen and dlsym to locate functions in libraries.
Example of interception:
cpp
Копировать код
void* (*original_open)(const char*, int);
void* hooked_open(const char* path, int flags) {
if (strstr(path, "target_file")) {
return nullptr;
}
return original_open(path, flags);
}
5.4. Logging
Use __android_log_print for debug logging.
Configurable log verbosity (e.g., arguments only, return value only, etc.).
6. Development Environment Requirements
Android Studio Arctic Fox or later.
Gradle 7.0+.
Android NDK (version 23+).
LSPosed API integrated into the project.
7. Deliverables
APK file of the module.
Source code with comments.
1. Introduction
The module is designed to operate within the LSPosed environment (an Xposed framework) that supports modifying system and user applications on Android devices. The goal is to create a native (C/C++) module for LSPosed capable of intercepting system method calls and functions, as well as altering their behavior.
2. Development Goals
Develop a module based on native code (C/C++).
Provide integration with LSPosed to intercept Java/ART (Android Runtime) functions and system libraries (via JNI).
Enable modification of the behavior of intercepted functions.
Support devices running Android 8.0 and above.
3. Main Requirements
3.1. Functional Requirements
Integration with LSPosed and module registration.
Interception of Java method calls via ART:
Specific classes/methods (e.g., android.location.LocationManager or java.lang.System).
Universal Java methods filtered by signatures.
Interception of native function calls from system libraries (e.g., via libc or libart.so).
Logging of calls and passed arguments.
Ability to modify return values.
3.2. Non-Functional Requirements
High performance with minimal system load.
Compatibility with LSPosed on Android 8.0+.
Minimal APK size with optimized native code usage.
4. Architecture
4.1. General Structure
Java Layer:
Interaction with LSPosed through the Java API.
Loading and initialization of the native library.
Interface for data transfer between Java and native code.
Native Layer:
Core library in C/C++.
Use of dlopen and dlsym for call interception.
Hooks via art::JNIEnv and ART native classes.
4.2. Tools and Libraries
Android NDK for native code development.
Hook Libraries (e.g., AndHook or frida-gum).
LSPosed API for integration.
5. Technical Details
5.1. Connecting to LSPosed
Register the module in AndroidManifest.xml with LSPosed API specification.
Create a Java class for interaction with LSPosed:
java
Копировать код
public class HookEntry implements IXposedHookLoadPackage {
@Override
public void handleLoadPackage(final LoadPackageParam lpparam) throws Throwable {
System.loadLibrary("native_hook");
NativeHook.init(lpparam.packageName);
}
}
5.2. Java Method Interception
Use ART API to locate and modify methods:
Obtain jclass via FindClass.
Obtain methods via GetMethodID/GetStaticMethodID.
Replace methods using art::Method.
5.3. Native Function Interception
Use dlopen and dlsym to locate functions in libraries.
Example of interception:
cpp
Копировать код
void* (*original_open)(const char*, int);
void* hooked_open(const char* path, int flags) {
if (strstr(path, "target_file")) {
return nullptr;
}
return original_open(path, flags);
}
5.4. Logging
Use __android_log_print for debug logging.
Configurable log verbosity (e.g., arguments only, return value only, etc.).
6. Development Environment Requirements
Android Studio Arctic Fox or later.
Gradle 7.0+.
Android NDK (version 23+).
LSPosed API integrated into the project.
7. Deliverables
APK file of the module.
Source code with comments.