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https://github.com/Youlor/Youpk
又一款基于ART的主动调用的脱壳机
https://github.com/Youlor/Youpk
unpacker
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又一款基于ART的主动调用的脱壳机
- Host: GitHub
- URL: https://github.com/Youlor/Youpk
- Owner: Youlor
- Created: 2020-05-30T12:46:24.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2021-10-21T06:28:29.000Z (about 3 years ago)
- Last Synced: 2024-08-05T17:30:34.915Z (4 months ago)
- Topics: unpacker
- Size: 9.77 KB
- Stars: 698
- Watchers: 12
- Forks: 134
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
- awesome-hacking-lists - Youlor/Youpk - 又一款基于ART的主动调用的脱壳机 (Others)
README
# Youpk: 又一款基于ART的主动调用的脱壳机
## 已开源
预祝大家儿童节快乐
仓库地址: https://github.com/youlor/unpacker, 欢迎各位大佬star.
## 原理
Youpk是一款针对Dex整体加固+各式各样的Dex抽取的脱壳机
基本流程如下:
1. 从内存中dump DEX
2. 构造完整调用链, 主动调用所有方法并dump CodeItem
3. 合并 DEX, CodeItem
### 从内存中dump DEX
DEX文件在art虚拟机中使用DexFile对象表示, 而ClassLinker中引用了这些对象, 因此可以采用从ClassLinker中遍历DexFile对象并dump的方式来获取.
```c++
//unpacker.cc
std::list Unpacker::getDexFiles() {
std::list dex_files;
Thread* const self = Thread::Current();
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
ReaderMutexLock mu(self, *class_linker->DexLock());
const std::list& dex_caches = class_linker->GetDexCachesData();
for (auto it = dex_caches.begin(); it != dex_caches.end(); ++it) {
ClassLinker::DexCacheData data = *it;
const DexFile* dex_file = data.dex_file;
dex_files.push_back(dex_file);
}
return dex_files;
}
```
另外, 为了避免dex做任何形式的优化影响dump下来的dex文件, 在dex2oat中设置 CompilerFilter 为仅验证
```c++
//dex2oat.cc
compiler_options_->SetCompilerFilter(CompilerFilter::kVerifyAtRuntime);
```
### 构造完整调用链, 主动调用所有方法
1. 创建脱壳线程
```java
//unpacker.java
public static void unpack() {
if (Unpacker.unpackerThread != null) {
return;
}
//开启线程调用
Unpacker.unpackerThread = new Thread() {
@Override public void run() {
while (true) {
try {
Thread.sleep(UNPACK_INTERVAL);
}
catch (InterruptedException e) {
e.printStackTrace();
}
if (shouldUnpack()) {
Unpacker.unpackNative();
}
}
}
};
Unpacker.unpackerThread.start();
}
```
2. 在脱壳线程中遍历DexFile的所有ClassDef
```c++
//unpacker.cc
for (; class_idx < dex_file->NumClassDefs(); class_idx++) {
```
3. 解析并初始化Class
```c++
//unpacker.cc
mirror::Class* klass = class_linker->ResolveType(*dex_file, dex_file->GetClassDef(class_idx).class_idx_, h_dex_cache, h_class_loader);
StackHandleScope<1> hs2(self);
Handle h_class(hs2.NewHandle(klass));
bool suc = class_linker->EnsureInitialized(self, h_class, true, true);
```
4. 主动调用Class的所有Method, 并修改ArtMethod::Invoke使其强制走switch型解释器
```c++
//art_method.cc
if (UNLIKELY(!runtime->IsStarted() || Dbg::IsForcedInterpreterNeededForCalling(self, this)
|| (Unpacker::isFakeInvoke(self, this) && !this->IsNative()))) {
if (IsStatic()) {
art::interpreter::EnterInterpreterFromInvoke(
self, this, nullptr, args, result, /*stay_in_interpreter*/ true);
} else {
mirror::Object* receiver =
reinterpret_cast*>(&args[0])->AsMirrorPtr();
art::interpreter::EnterInterpreterFromInvoke(
self, this, receiver, args + 1, result, /*stay_in_interpreter*/ true);
}
}
//interpreter.cc
static constexpr InterpreterImplKind kInterpreterImplKind = kSwitchImplKind;
```
5. 在解释器中插桩, 在每条指令执行前设置回调
```c++
//interpreter_switch_impl.cc
// Code to run before each dex instruction.
#define PREAMBLE() \
do { \
inst_count++; \
bool dumped = Unpacker::beforeInstructionExecute(self, shadow_frame.GetMethod(), \
dex_pc, inst_count); \
if (dumped) { \
return JValue(); \
} \
if (UNLIKELY(instrumentation->HasDexPcListeners())) { \
instrumentation->DexPcMovedEvent(self, shadow_frame.GetThisObject(code_item->ins_size_), shadow_frame.GetMethod(), dex_pc); \
} \
} while (false)
```
6. 在回调中做针对性的CodeItem的dump, 这里仅仅是简单的示例了直接dump, 实际上, 针对某些厂商的抽取, 可以真正的执行几条指令等待CodeItem解密后再dump
```c++
//unpacker.cc
bool Unpacker::beforeInstructionExecute(Thread *self, ArtMethod *method, uint32_t dex_pc, int inst_count) {
if (Unpacker::isFakeInvoke(self, method)) {
Unpacker::dumpMethod(method);
return true;
}
return false;
}
```
### 合并 DEX, CodeItem
将dump下来的CodeItem填充到DEX的相应位置中即可. 主要是基于google dx工具修改.
### 参考链接
FUPK3: https://bbs.pediy.com/thread-246117.htm
FART: https://bbs.pediy.com/thread-252630.htm
## 刷机
1. 仅支持pixel 1代
2. 重启至bootloader: `adb reboot bootloader`
3. 解压 Youpk_sailfish.zip 并双击 `flash-all.bat`
百度云：https://pan.baidu.com/s/1nUC5PpYGEBvkuvV-82pluA
提取码：sc82
## 使用方法
1. **该工具仅仅用来学习交流, 请勿用于非法用途, 否则后果自付！**
2. 配置待脱壳的app包名, 准确来讲是进程名称
```bash
adb shell "echo cn.youlor.mydemo >> /data/local/tmp/unpacker.config"
```
3. 启动apk等待脱壳
每隔10秒将自动重新脱壳(已完全dump的dex将被忽略), 当日志打印unpack end时脱壳完成
4. pull出dump文件, dump文件路径为 `/data/data/包名/unpacker`
```bash
adb pull /data/data/cn.youlor.mydemo/unpacker
```
5. 调用修复工具 dexfixer.jar, 两个参数, 第一个为dump文件目录(必须为有效路径), 第二个为重组后的DEX目录(不存在将会创建)
```bash
java -jar dexfixer.jar /path/to/unpacker /path/to/output
```
## 常见问题
1. dump中途退出或卡死，重新启动进程，再次等待脱壳即可
2. 当前仅支持被壳保护的dex, 不支持App动态加载的dex/jar