某手新版本sig3参数算法还原

Frida Native层主动调用

export function callDoCommandNative(){ // jni方法复习

Java.perform(function() {

var base_addr = Module.findBaseAddress("libkwsgmain.so") || ptr(0x0);

var real_addr = base_addr.add(0x41680)

var docommand = new NativeFunction(real_addr, "pointer", ["pointer", "pointer", "int", "pointer"]);

var JNIEnv = Java.vm.getEnv();

var Intger = Java.use("java.lang.Integer");

var jstring = Java.use("java.lang.String");

var Boolean = Java.use("java.lang.Boolean");

var cla = JNIEnv.findClass("java/lang/Object");

// args1:,d7b7d042-d4f2-4012-be60-d97ff2429c17,,,com.yxcorp.gifshow.App@27101bb,,'} data: None

var currentApplication = Java.use("android.app.ActivityThread").currentApplication();

var context = currentApplication.getApplicationContext();

log("context"+context)

var input_1 = JNIEnv.newStringUtf('d7b7d042-d4f2-4012-be60-d97ff2429c17');

var argList_0 = JNIEnv.newObjectArray(7, cla, ptr(0x0));

JNIEnv.setObjectArrayElement(argList_0, 0, ptr(0x0));

JNIEnv.setObjectArrayElement(argList_0, 1, input_1);

JNIEnv.setObjectArrayElement(argList_0, 2, ptr(0x0));

JNIEnv.setObjectArrayElement(argList_0, 3, ptr(0x0));

JNIEnv.setObjectArrayElement(argList_0, 4, context.$h);

JNIEnv.setObjectArrayElement(argList_0, 5, ptr(0x0));

JNIEnv.setObjectArrayElement(argList_0, 6, ptr(0x0));

var point_0 = docommand(JNIEnv, ptr(0x0), 10412, argList_0); // 返回的是指针，通过cast转成java对象，从而读出来

console.log("point_0: " + point_0);

var s_0 = Java.cast(point_0, Java.use("java.lang.Object"));

console.log("result: " + s_0);

var argList = JNIEnv.newObjectArray(8, cla, ptr(0x0));

var argList_1 = JNIEnv.newObjectArray(1, cla, ptr(0x0));

var input0 = JNIEnv.newStringUtf('/rest/n/feed/selectionbb9caf23ee1fda57a6c167198aba919f');

var input1 = JNIEnv.newStringUtf('d7b7d042-d4f2-4012-be60-d97ff2429c17');

var input2 = Boolean.$new(false);

var input2_2 = Boolean.$new(false);

var input3 = Intger.$new(-1);

var input5 = JNIEnv.newStringUtf("010a11c6-f2cb-4016-887d-0d958aef1534");

JNIEnv.setObjectArrayElement(argList_1, 0, input0);

JNIEnv.setObjectArrayElement(argList, 0, argList_1);

JNIEnv.setObjectArrayElement(argList, 1, input1);

JNIEnv.setObjectArrayElement(argList, 2, input3.$h);

JNIEnv.setObjectArrayElement(argList, 3, input2.$h);

JNIEnv.setObjectArrayElement(argList, 4, ptr(0x0));

JNIEnv.setObjectArrayElement(argList, 5, ptr(0x0));

JNIEnv.setObjectArrayElement(argList, 6, input2_2.$h);

JNIEnv.setObjectArrayElement(argList, 7, input5);

var point = docommand(JNIEnv, ptr(0x0), 10418, argList); // 返回的是指针，通过cast转成java对象，从而读出来

var s = Java.cast(point, Java.use("java.lang.Object")); // $className : java.lang.String

console.log("result: " + s);

console.log("result: " + Java.vm.tryGetEnv().getStringUtfChars(point).readCString());

})

}

export function jniOnload(){

var android_dlopen_ext = Module.findExportByName(null, "android_dlopen_ext");

if (android_dlopen_ext != null) {

Interceptor.attach(android_dlopen_ext, {

onEnter: function (args) {

this.hook = false;

var soName = args[0].readCString() || '';

if (soName.indexOf("libkwsgmain.so") !== -1) {

this.hook = true;

}

},

onLeave: function (retval) {

if (this.hook) {

var jniOnload = Module.findExportByName("libkwsgmain.so", "JNI_OnLoad") || ptr(0x0);

Interceptor.attach(jniOnload, {

onEnter: function (args) {

console.log("Enter Mtguard JNI OnLoad");

},

onLeave: function (retval) {

console.log("After Mtguard JNI OnLoad");

callDoCommandNative();

// hook_ks();

}

});

}

});

}

这里踩了一个坑，传入的对象数组里有个元素是context类型，打印出来是com.yxcorp.gifshow.App@b97f2c，所以想当然的就按这个类直接new了个对象传了进去，很快出现了报错：

这个报错让我百思不得其解，压根就没往context这块想，以为哪怕填个空指针都没问题的。

最后，用笨法frida hooknative层地址，打印定位，找到了如此地方：

此处判断X23的值是否为0，正常打印出来是/data/app/com.smile.gifmaker-q14Fo0PSb77vTIOM1-iEqQ==/base.apk，调用了getPackageCodePath 方法。

这是一个context方法，那必须传入有效的context：

1 2	`var` `currentApplication = Java.use("android.app.ActivityThread").currentApplication();` `var` `context = currentApplication.getApplicationContext();`

解决方法就是如此简单，基础，却让我绕了一大圈弯路，不得不感叹，基础真重要啊！

IDA静态分析

花指令
- 这块看龙哥的分析就好了，非常清晰

Unidbg模拟执行

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package com.smile.gifmaker3;

import com.github.unidbg.*;

import com.github.unidbg.Module;

import com.github.unidbg.arm.backend.Backend;

import com.github.unidbg.arm.backend.CodeHook;

import com.github.unidbg.arm.backend.UnHook;

import com.github.unidbg.arm.backend.UnicornBackend;

import com.github.unidbg.arm.context.Arm32RegisterContext;

import com.github.unidbg.arm.context.Arm64RegisterContext;

import com.github.unidbg.file.FileResult;

import com.github.unidbg.file.IOResolver;

import com.github.unidbg.file.linux.AndroidFileIO;

import com.github.unidbg.linux.android.AndroidEmulatorBuilder;

import com.github.unidbg.linux.android.AndroidResolver;

import com.github.unidbg.linux.android.dvm.*;

import com.github.unidbg.linux.android.dvm.api.AssetManager;

import com.github.unidbg.linux.android.dvm.array.ArrayObject;

import com.github.unidbg.linux.android.dvm.wrapper.DvmBoolean;

import com.github.unidbg.linux.android.dvm.wrapper.DvmInteger;

import com.github.unidbg.memory.Memory;

import com.github.unidbg.pointer.UnidbgPointer;

import com.github.unidbg.spi.SyscallHandler;

import com.github.unidbg.utils.Inspector;

import com.github.unidbg.virtualmodule.android.AndroidModule;

import com.github.unidbg.virtualmodule.android.JniGraphics;

import com.sun.jna.Pointer;

import king.trace.GlobalData;

import king.trace.KingTrace;

import unicorn.Unicorn;

import unicorn.UnicornConst;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.PrintStream;

import java.nio.ByteBuffer;

import java.nio.ByteOrder;

import java.util.ArrayList;

import java.util.List;

public class kswgmain11420 extends AbstractJni implements IOResolver {

private final AndroidEmulator emulator;

private final VM vm;

private final Module module;

kswgmain11420() throws FileNotFoundException {

// 创建模拟器实例，要模拟32位或者64位，在这里区分

EmulatorBuilder<AndroidEmulator> builder = AndroidEmulatorBuilder.for64Bit().setProcessName("com.smile.gifmaker");

emulator = builder.build();

emulator.getSyscallHandler().setEnableThreadDispatcher(true);

// 模拟器的内存操作接口

final Memory memory = emulator.getMemory();

// 设置系统类库解析

memory.setLibraryResolver(new AndroidResolver(23));

// 创建Android虚拟机

// vm = emulator.createDalvikVM();

vm = emulator.createDalvikVM(new File("unidbg-android\\src\\test\\java\\com\\smile\\gifmaker3\\1142064wei.apk"));

// 设置是否打印Jni调用细节

vm.setVerbose(true);

new JniGraphics(emulator, vm).register(memory);

new AndroidModule(emulator, vm).register(memory);

vm.setJni(this);

SyscallHandler<AndroidFileIO> handler = emulator.getSyscallHandler();

handler.addIOResolver(this);

// 加载libttEncrypt.so到unicorn虚拟内存，加载成功以后会默认调用init_array等函数

DalvikModule dm = vm.loadLibrary(new File("unidbg-android\\src\\test\\java\\com\\smile\\gifmaker3\\libkwsgmain.so"), true);

// 加载好的libttEncrypt.so对应为一个模块

module = dm.getModule();

// trace code

// String traceFile = "unidbg-android\\src\\test\\java\\com\\smile\\gifmaker3\\sig3_jniOnload.trc";

// GlobalData.ignoreModuleList.add("libc.so");

// GlobalData.ignoreModuleList.add("libhookzz.so");

// GlobalData.ignoreModuleList.add("libc++_shared.so");

// emulator.traceCode(module.base, module.base+module.size).setRedirect(new PrintStream(new FileOutputStream(traceFile), true));

dm.callJNI_OnLoad(emulator);

}

public static void main(String[] args) throws FileNotFoundException {

kswgmain11420 kk = new kswgmain11420();

kk.init_native();

kk.get_NS_sig3();

}

public void init_native() throws FileNotFoundException {

// trace code

// String traceFile = "unidbg-android\\src\\test\\java\\com\\smile\\gifmaker3\\sig3_init_native.trc";

// GlobalData.ignoreModuleList.add("libc.so");

// GlobalData.ignoreModuleList.add("libhookzz.so");

// GlobalData.ignoreModuleList.add("libc++_shared.so");

// emulator.traceCode(module.base, module.base+module.size).setRedirect(new PrintStream(new FileOutputStream(traceFile), true));

List<Object> list = new ArrayList<>(10);

list.add(vm.getJNIEnv()); // 第一个参数是env

DvmObject<?> thiz = vm.resolveClass("com/kuaishou/android/security/internal/dispatch/JNICLibrary").newObject(null);

list.add(vm.addLocalObject(thiz)); // 第二个参数，实例方法是jobject，静态方法是jclass，直接填0，一般用不到。

DvmObject<?> context = vm.resolveClass("com/yxcorp/gifshow/App").newObject(null); // context

vm.addLocalObject(context);

list.add(10412); //参数1

StringObject appkey = new StringObject(vm,"d7b7d042-d4f2-4012-be60-d97ff2429c17"); // SO文件有校验

vm.addLocalObject(appkey);

DvmInteger intergetobj = DvmInteger.valueOf(vm, 0);

vm.addLocalObject(intergetobj);

list.add(vm.addLocalObject(new ArrayObject(intergetobj,appkey,intergetobj,intergetobj,context,intergetobj,intergetobj)));

// 直接通过地址调用

Number numbers = module.callFunction(emulator, 0x41680, list.toArray());

System.out.println("numbers:"+numbers);

DvmObject<?> object = vm.getObject(numbers.intValue());

String result = (String) object.getValue();

System.out.println("result:"+result);

}

@Override

public DvmObject<?> callObjectMethodV(BaseVM vm, DvmObject<?> dvmObject, String signature, VaList vaList) {

switch (signature) {

case "com/yxcorp/gifshow/App->getPackageCodePath()Ljava/lang/String;": {

return new StringObject(vm, "/data/app/com.smile.gifmaker-q14Fo0PSb77vTIOM1-iEqQ==/base.apk");

}

case "com/yxcorp/gifshow/App->getAssets()Landroid/content/res/AssetManager;": {

// return new Long(vm, "3817726272");

return new AssetManager(vm, signature);

}

case "com/yxcorp/gifshow/App->getPackageName()Ljava/lang/String;": {

return new StringObject(vm, "com.smile.gifmaker");

}

case "com/yxcorp/gifshow/App->getPackageManager()Landroid/content/pm/PackageManager;": {

DvmClass clazz = vm.resolveClass("android/content/pm/PackageManager");

return clazz.newObject(signature);

}

return super.callObjectMethodV(vm, dvmObject, signature, vaList);

}

@Override

public boolean callBooleanMethodV(BaseVM vm, DvmObject<?> dvmObject, String signature, VaList vaList) {

switch (signature) {

case "java/lang/Boolean->booleanValue()Z":

DvmBoolean dvmBoolean = (DvmBoolean) dvmObject;

return dvmBoolean.getValue();

}

return super.callBooleanMethodV(vm, dvmObject, signature, vaList);

}

public String get_NS_sig3() throws FileNotFoundException {

// trace code

// String traceFile = "unidbg-android\\src\\test\\java\\com\\smile\\gifmaker3\\sig3_new.trc";

// GlobalData.ignoreModuleList.add("libc.so");

// GlobalData.ignoreModuleList.add("libhookzz.so");

// GlobalData.ignoreModuleList.add("libc++_shared.so");

// emulator.traceCode(module.base, module.base+module.size).setRedirect(new PrintStream(new FileOutputStream(traceFile), true));

System.out.println("_NS_sig3 start");

List<Object> list = new ArrayList<>(10);

list.add(vm.getJNIEnv()); // 第一个参数是env

DvmObject<?> thiz = vm.resolveClass("com/kuaishou/android/security/internal/dispatch/JNICLibrary").newObject(null);

list.add(vm.addLocalObject(thiz)); // 第二个参数，实例方法是jobject，静态方法是jclass，直接填0，一般用不到。

DvmObject<?> context = vm.resolveClass("com/yxcorp/gifshow/App").newObject(null); // context

vm.addLocalObject(context);

list.add(10418); //参数1

StringObject urlObj = new StringObject(vm, "/rest/app/eshop/ks/live/item/byGuest6bcab0543b7433b6d0771892528ef686");

vm.addLocalObject(urlObj);

ArrayObject arrayObject = new ArrayObject(urlObj);

StringObject appkey = new StringObject(vm,"d7b7d042-d4f2-4012-be60-d97ff2429c17");

vm.addLocalObject(appkey);

DvmInteger intergetobj = DvmInteger.valueOf(vm, -1);

vm.addLocalObject(intergetobj);

DvmBoolean boolobj = DvmBoolean.valueOf(vm, false);

vm.addLocalObject(boolobj);

StringObject appkey2 = new StringObject(vm,"7e46b28a-8c93-4940-8238-4c60e64e3c81");

vm.addLocalObject(appkey2);

list.add(vm.addLocalObject(new ArrayObject(arrayObject,appkey,intergetobj,boolobj,context,null,boolobj,appkey2)));

// 直接通过地址调用

Number numbers = module.callFunction(emulator, 0x41680, list.toArray());

System.out.println("numbers:"+numbers);

DvmObject<?> object = vm.getObject(numbers.intValue());

String result = (String) object.getValue();

System.out.println("result:"+result);

return result;

}

@Override

public FileResult resolve(Emulator emulator, String pathname, int oflags) {

System.out.println("fuck:"+pathname);

return null;

}

public String readStdString(Pointer strptr){

Boolean isTiny = (strptr.getByte(0) & 1) == 0;

if(isTiny){

return strptr.getString(1);

}

return strptr.getPointer(emulator.getPointerSize()* 2L).getString(0);

}

@Override

public DvmObject<?> callStaticObjectMethodV(BaseVM vm, DvmClass dvmClass, String signature, VaList vaList) {

switch (signature) {

case "com/kuaishou/android/security/internal/common/ExceptionProxy->getProcessName(Landroid/content/Context;)Ljava/lang/String;":

return new StringObject(vm, "com.smile.gifmaker");

case "com/meituan/android/common/mtguard/NBridge->getSecName()Ljava/lang/String;":

return new StringObject(vm, "ppd_com.sankuai.meituan.xbt");

case "com/meituan/android/common/mtguard/NBridge->getAppContext()Landroid/content/Context;":

return vm.resolveClass("android/content/Context").newObject(null);

case "com/meituan/android/common/mtguard/NBridge->getMtgVN()Ljava/lang/String;":

return new StringObject(vm, "4.4.7.3");

case "com/meituan/android/common/mtguard/NBridge->getDfpId()Ljava/lang/String;":

return new StringObject(vm, "");

}

return super.callStaticObjectMethodV(vm, dvmClass, signature,vaList);

}

这里也有一个小tips，让unidbg加载指定SO文件，如果这个SO有依赖其他的SO库，那么很有可能会加载失败。这个情况不同于直接加载apk文件里的so文件，那种情况下unidbg会帮我们自动去寻找需要的SO文件。这个情况下，我们只要把需要的SO文件提取出来，放在同一目录下即可。

trace code

用去花后的so文件，trace关键函数，很快的。

SHA256还原

结合ida伪代码和sha256的伪代码，还原

思路：先看iv和table，然后看明文编排，最后比对具体运算 ———— 龙哥语录
sha256算法基础

确定调用栈

[确定调用堆栈]
找到sig3最先出现的地方
sub_2636c 编排地址：

sub_2BD20
sub_25938
sub_120C4

至此，明文输入字符串的加密结果拿到

拼接过程

固定字符串
随机字符串
- 猜测是随机，进一步验证，追踪，在JNI_OnLoad里:

明文字符加密结果
时间戳
固定字符串