iOS逆向记录(三)

8.第一个逆向程序

创建tweak工程

➜  iOS /opt/theos/bin/nic.pl 
NIC 2.0 - New Instance Creator
------------------------------
  [1.] iphone/activator_event
  [2.] iphone/application_modern
  [3.] iphone/cydget
  [4.] iphone/flipswitch_switch
  [5.] iphone/framework
  [6.] iphone/ios7_notification_center_widget
  [7.] iphone/library
  [8.] iphone/notification_center_widget
  [9.] iphone/preference_bundle_modern
  [10.] iphone/tool
  [11.] iphone/tweak
  [12.] iphone/xpc_service
 //选择tweak工程  
Choose a Template (required): 11  
 
 //工程名称
Project Name (required): MyFirstReProject  
 
//deb包的名字（类似于bundle identifier)
Package Name [com.yourcompany.myfirstreproject]: com.iosre.myfirstreproject  
 
//tweak作者
Author/Maintainer Name [System Administrator]: Flonger 
 
//tweak作用对象的bundle identifier
[iphone/tweak] MobileSubstrate Bundle filter [com.apple.springboard]: com.apple.springboard 
 
//tweak安装完成后需要重启的应用
[iphone/tweak] List of applications to terminate upon installation (space-separated, '-' for none) [SpringBoard]: SpringBoard
Instantiating iphone/tweak in myfirstreproject/...
Done.

工程文件结构介绍

Makefile

//工程包含的通用头文件
include $(THEOS)/makefiles/common.mk

//创建工程时指定的“Project Name，指定好之后一般不要再更改
TWEAK_NAME = MyFirstReProject
 
//tweak包含的源文件，指定多个文件时用空格隔开
MyFirstReProject_FILES = Tweak.xm

//tweak工程的头文件，一般有application.mk、tweak.mk和tool.mk几类
include $(THEOS_MAKE_PATH)/tweak.mk

//指定tweak安装之后，需要做的事情，这里是杀掉SpringBoard进程 
after-install::
    install.exec "killall -9 SpringBoard"
     
补充:
//编译debug或者release
DEBUG = 0
 
//越狱iPhone的ip地址
THEOS_DEVICE_IP = 192.168.1.113
 
//指定支持的处理器架构
ARCHS = armv7 arm64 
 
//指定需要的SDK版本iphone:Base SDK:Deployment Target
TARGET = iphone:latest:8.0  //最新的SDK，程序发布在iOS8.0以上

//导入框架，多个框架时用空格隔开
MyFirstReProject_FRAMEWORKS = UIKit 
MyFirstReProject_PRIVATE_FRAMEWORKS = AppSupport
 
//链接libsqlite3.0.dylib、libz.dylib和dylib1.o
MyFirstReProject_LDFLAGS = -lz –lsqlite3.0 –dylib1.o
 
//make clean
clean::
    rm -rf ./packages/*

tweak文件
“xm”中的“x”代表这个文件支持Logos语法，如果后缀名是单独一个“x”，说明源文件支持Logos和C语法；如果后缀名是“xm”
，说明源文件支持Logos和C/C++语法。

/* How to Hook with Logos
Hooks are written with syntax similar to that of an Objective-C @implementation.
You don't need to #include <substrate.h>, it will be done automatically, as will
the generation of a class list and an automatic constructor.

%hook ClassName

// Hooking a class method
+ (id)sharedInstance {
    return %orig;
}

// Hooking an instance method with an argument.
- (void)messageName:(int)argument {
    %log; // Write a message about this call, including its class, name and arguments, to the system log.

    %orig; // Call through to the original function with its original arguments.
    %orig(nil); // Call through to the original function with a custom argument.

    // If you use %orig(), you MUST supply all arguments (except for self and _cmd, the automatically generated ones.)
}

// Hooking an instance method with no arguments.
- (id)noArguments {
    %log;
    id awesome = %orig;
    [awesome doSomethingElse];

    return awesome;
}

// Always make sure you clean up after yourself; Not doing so could have grave consequences!
%end
*/

%hook 指定需要hook的class，必须以%end结尾
%log 该指令在%hook内部使用，将函数的类名、参数等信息写入syslog
Cydia内搜索安装syslogd
%orig该指令在%hook内部使用，执行被钩住（hook）的函数的原始代码。

control
control文件记录了deb包管理系统所需的基本信息，会被打包进deb包里。

编译工程

tweakxm 文件

%hook SpringBoard 
-  (void)applicationDidFinishLaunching:(id)application 
{ 
    %orig; 
    UIAlertView *alert = [[UIAlertView alloc]  
    initWithTitle:@"Hello，Tanzhou!" 
    message:nil 
    delegate:self cancelButtonTitle:@"OK"
    otherButtonTitles:nil]; 
    [alert show]; 
}

- (void)_menuButtonDown:(id)down  
{  
    NSLog(@"x=%d, y=%d", 10, 20);
    %log((NSString *)@"iOSRE", (NSString *)@"Debug");  
    %orig; // call the original _menuButtonDown:
}
%end

%hook SBLockScreenDateViewController
- (void)setCustomSubtitleText:(id)arg1 withColor:(id)arg2
{
/*
   NSDate *date=[NSDate date];
   NSDateFormatter *format1=[[NSDateFormatter alloc]init];
   [format1 setDateFormat:@"yyyy/MM/dd HH:mm:ss"];   
   NSString *str1=[format1 stringFromDate:date];
*/
   struct tm *loctime;
   char timeBuf[1024] = {0};
   time_t now = time(NULL);
   loctime = localtime(&now);
   strftime(timeBuf, 30, "[%Y/%m/%d %H:%M:%S]", loctime);
   %orig([NSString stringWithUTF8String:timeBuf],arg2);   
}
%end

MakeFile文件

DEBUG = 0
THEOS_DEVICE_IP = 10.171.4.22 
ARCHS = armv7 arm64 
TARGET = iphone:latest:8.0  
include $(THEOS)/makefiles/common.mk

TWEAK_NAME = MyFirstReProject
MyFirstReProject_FILES = Tweak.xm
MyFirstReProject_FRAMEWORKS = UIKit 
include $(THEOS_MAKE_PATH)/tweak.mk

after-install::
    install.exec "killall -9 SpringBoard"
clean::
    rm -rf ./packages/*

control文件

Package: com.iosre.myfirstreproject
Name: MyFirstReProject
Depends: mobilesubstrate
Version: 1.0.1
Architecture: iphoneos-arm
Description: My first reproject!
Maintainer: Flonger
Author: Flonger
Section: Tweaks
Homepage: https://www.baidu.com

编译命令

make  //编译

make package  //打包
 
make install  //安装

验证结果

9.deb包介绍

官网：http://www.debian.org/doc/debian-policy/

deb包本质是一个压缩包文件。里面包含一些特定的目录和文件。安装过程就是dpkg程序按照指定的规则去拷贝文件和执行脚本。

dpkg -c  xxxx.deb //查看deb包的目录结构

DEBIAN目录
存放control文件、及安装和卸载时需要执行的脚本等

control文件导出。。

   //deb包的名字，卸载和查询包信息都用这个名字
    Package: com.iosre.myfirstreproject

    //工程名字(产品名字)
    Name: MyFirstReProject

    //依赖包（可以指定多个，用','分割）
    Depends: mobilesubstrate, firmware  (>=8.0)

    //deb包版本号
    Version: 1.0.1

    //描述软件所支持的平台架构
    Architecture: iphoneos-arm

    //deb包简介
    Description: My first reproject!

    //deb包维护人和联系方式
    Maintainer: Flonger<xue@flonger.com>

    //软件作者
    Author: Fonger

    //deb包归属类别
    Section: Tweaks

    //软件主页
    Homepage: https://www.baidu.com

脚本文件

preinst
在Deb包文件解包之前，将会运行该脚本。许多“preinst”脚本的任务是停止作用于待升级软件包的服务，直到软件包安装或升级完成。

postinst
该脚本的主要任务是完成安装包时的配置工作。许多“postinst”脚本负责执行有关命令为新安装或升级的软件重启服务。

prerm
该脚本负责停止与软件包相关联的daemon服务。它在删除软件包关联文件之前执行。

postrm
该脚本负责修改软件包链接或文件关联，或删除由它创建的文件。

dpkg打包时会复制当前目录下layout目录下的所有文件和目录
这些文件和目录会镜像到目标设备上（layout相对于设备的根目录）

//发布时的Makefile
DEBUG = 0
THEOS_DEVICE_IP = 10.171.4.22 
ARCHS = armv7 arm64 
TARGET = iphone:latest:8.0  
include $(THEOS)/makefiles/common.mk

TWEAK_NAME = MyFirstReProject
MyFirstReProject_FILES = Tweak.xm
MyFirstReProject_FRAMEWORKS = UIKit 
include $(THEOS_MAKE_PATH)/tweak.mk

clean::
    rm -rf ./packages/* 
before-package::
    cp ./script/postinst ./.theos/_/DEBIAN/
    cp ./script/postrm ./.theos/_/DEBIAN/

10. 常见Logos语法介绍

维基百科：http://iphonedevwiki.net/index.php/Logos

10.1 Block-level

%hook
指定需要hook的class,必须以％end结尾。可以被%group包含

%hook SBApplicationController
-(void)uninstallApplication:(SBApplication *)application {
    NSLog(@"Hey, we're hooking uninstallApplication:!");
    %orig; // Call the original implementation of this method
    return;
}
%end

%group
该指令用于将%hook分组，便于代码管理及按条件初始化分组，必须以%end结尾。
一个％group可以包含多个%hook,所有不属于某个自定义group的％hook会被隐式归类到％group_ungrouped中。

%group iOS8
%hook IOS8_SPECIFIC_CLASS
    // your code here
%end // end hook
%end // end group ios8

%group iOS9
%hook IOS9_SPECIFIC_CLASS
    // your code here
%end // end hook
%end // end group ios9

%ctor {
    if (kCFCoreFoundationVersionNumber > 1200) {
        %init(iOS9);
    } else {
        %init(iOS8);
    }
}

%new
在%hook内部使用，给一个现有class添加新函数，功能与class_addMethod相同。
注： Objective-C的category与class_addMethod的区别：前者是静态的而后者是动态的。

%hook SBApplicationController
-(void)uninstallApplication:(SBApplication *)application {
    NSLog(@"Hey, we're hooking uninstallApplication:!");
    %orig; // Call the original implementation of this method
    return;
}

%new
- (void)namespaceNewMethod
{
NSLog(@"We've added a new method to SpringBoard.");
}
%end

10.2 Top level

%ctor
tweak的构造函数,完成初始化工作；如果不显示定义，Theos会自动生成一个%ctor,并在其中调用%init(_ungrouped)。
%dtor
tweak的构造函数,完成收尾。如果不显示定义，Theos会自动生成一个%dtor。

10.3 Function level

%init
该指令用于初始化某个％group，必须在%hook或％ctor内调用；如果带参数，则初始化指定的group，如果不带参数，则初始化_ungrouped.
注：切记，只有调用了％ini,对应的%group才能起作用！

%ctor {
    if (kCFCoreFoundationVersionNumber > 1200) %init(iOS9);
     else %init(iOS8);
}

%c
该指令的作用等同于objc_getClass或NSClassFromString,即动态获取一个类的定义，在%hook或％ctor内使用。

%hook SpringBoard
- (void)_menuButtonDown:(id)down
{
%orig;
SBScreenShotter *shotter = [%c(SBScreenShotter) sharedInstance];
[shotter saveScreenshot:YES]; 
}
%end@

％log
该指令在%hook内部使用，将函数的类名、参数等信息写入syslog,可以％log([(),…..])的格式追加其他打印信息。

tail -f /var/log/syslog | grep WeChat

％orig
该指令在%hook内部使用，执行被hook的函数的原始代码；也可以用％orig更改原始函数的参数。

//练习
@interface SBScreenshotter: NSObject
+ (id)sharedInstance;
- (void)saveScreenshot: (BOOL)arg1;
@end
 
@interface SpringBoard
+ (void)_AutoScreenSave2;
- (void)_AutoScreenSave;
@end
 
%hook SpringBoard 
-  (void)applicationDidFinishLaunching:(id)application 
{ 
    %orig; 
    UIAlertView *alert = [[UIAlertView alloc]  
    initWithTitle:@"Hello，Tanzhou!" 
    message:nil 
    delegate:self cancelButtonTitle:@"OK"
    otherButtonTitles:nil]; 
    [alert show]; 
}
 
%new
- (void)_AutoScreenSave
{
    NSLog(@"instance method");
    SBScreenShotter *shotter = [%c(SBScreenShotter) sharedInstance];
    [shotter saveScreenshot:YES]; 
}
 
%new
+ (void)_AutoScreenSave2
{
    NSLog(@"class method");
    SBScreenShotter *shotter = [%c(SBScreenShotter) sharedInstance];
    [shotter saveScreenshot:YES]; 
}
 
- (void)_menuButtonDown:(id)down  
{  
    //SBScreenShotter *shotter = [%c(SBScreenShotter) sharedInstance];
    //[shotter saveScreenshot:YES];
    //[self _AutoScreenSave]; 
    [%c(SpringBoard) _AutoScreenSave2];
    NSLog(@"x=%d, y=%d", 10, 20);
    %log((NSString *)@"iOSRE", (NSString *)@"Debug");  
    %orig; // call the original _menuButtonDown:
}
%end
 
%hook SBLockScreenDateViewController
- (void)setCustomSubtitleText:(id)arg1 withColor:(id)arg2
{
/*
   NSDate *date=[NSDate date];
   NSDateFormatter *format1=[[NSDateFormatter alloc]init];
   [format1 setDateFormat:@"yyyy/MM/dd HH:mm:ss"];   
   NSString *str1=[format1 stringFromDate:date];
*/
   struct tm *loctime;
   char timeBuf[1024] = {0};
   time_t now = time(NULL);
   loctime = localtime(&now);
   strftime(timeBuf, 30, "[%Y/%m/%d %H:%M:%S]", loctime);
   %orig([NSString stringWithUTF8String:timeBuf],arg2);   
}
%end
 
 
/*
%group HookTest
%hook SpringBoard
- (void)_lockButtonDown:(struct __IOHIDEvent *)arg1 fromSource:(int)arg2
{
  NSLog(@"_lockButtonDown");
}
 
- (void)_lockButtonUp:(struct __IOHIDEvent *)arg1 fromSource:(int)arg2
{
  NSLog(@"_lockButtonUp");
}
 
- (void)powerDownCanceled:(id)arg1
{
  NSLog(@"powerDownCanceled");
  %orig;
}
 
- (void)powerDown
{
  NSLog(@"powerDown");
}  
 
- (void)powerDownRequested:(id)arg1
{
  NSLog(@"powerDownRequested");
}
%end
%end
*/
 
%ctor
{
  %init(_ungrouped);
  //%init(HookTest);
}

11.Tweak工作原理

1.Cydia Substrate 和 Mobile Substrate

Cydia Substrate 原名为 Mobile Substrate 已经正式更名为 Cydia Substrate。
它是越狱后cydia插件/软件(主要指theos开发的tweak)运行的一个基础依赖包。提供软件运行的公共库，可以用来动态替换内存中的代码、数据等所以iOS系统越狱环境下安装绝大部分插件，必须首先安装Cydia Substrate。
Cydia Substrate主要由3部分组成：MobileHooker，MobileLoader 和 safe mode。

2.MobileHooker

MobileHooker用于替换覆盖系统的方法，这个过程被称为Hooking(挂钩)
它主要包含两个函数：
void MSHookMessageEx(Class class, SEL selector, IMP replacement, IMP *result);

void MSHookFunction(voidfunction,void replacement,void** p_original);

MSHookMessageEx 主要作用于Objective-C函数

MSHookFunction 主要作用于C和C++函数

Logos语法%hook就是对此函数做了一层封装，让编写hook代码变的更直观，上面的例子用的就是logos语法。

MSHookMessageEx
http://www.cydiasubstrate.com/api/c/MSHookMessageEx/

void MSHookMessageEx(Class _class, SEL message, IMP hook, IMP *old);

NSString *(*oldDescription)(id self, SEL _cmd);
 
// implicit self and _cmd are explicit with IMP ABI
NSString *newDescription(id self, SEL _cmd) {
    NSString *description = (*oldDescription)(self, _cmd);
    description = [description stringByAppendingString:@"!"];
    return description;
}

MSHookMessageEx(
    [NSObject class], @selector(description),&newDescription, &oldDescription
);

MSHookFunction
http://www.cydiasubstrate.com/api/c/MSHookFunction/

void MSHookFunction(void *symbol, void *hook, void **old);

void *(*oldConnect)(int, const sockaddr *, socklen_t);

void *newConnect(
    int socket, const sockaddr *address, socklen_t length
) {
    if (address->sa_family == AF_INET) {
        sockaddr_in *address_in = address;
        if (address_in->sin_port == htons(6667)) {
            sockaddr_in copy = *address_in;
            address_in->sin_port = htons(7001);
            return oldConnect(socket, ©, length);
        }
    }

    return oldConnect(socket, address, length);
}

MSHookFunction(&connect, &newConnect, &oldConnect);

3.MobileLoader

MobileLoader 将tweak插件注入到第三方应用程序中（动态注入：ptrace）

启动时MobileLoader会根据/Library/MobileSubstrate/DynamicLibraries/目录中plist文件指定的作用范围，
有选择的在第三方进程空间里通过dlopen函数加载同名的dylib。

每一个.dylib文件都会有一个同名的.plist文件。.plist文件的作用就是用来指定tweak插件的作用对象。

Flongers-iphone:/Library/MobileSubstrate/DynamicLibraries root# pwd
/Library/MobileSubstrate/DynamicLibraries
 
Flongers-iphone:/Library/MobileSubstrate/DynamicLibraries root# ls
  AppList.dylib@         MFService.dylib*         MyFirstReProject.plist   afc2dService.dylib*
  AppList.plist          MFService.plist*         PreferenceLoader.dylib*  afc2dService.plist
  MFAccelerator.dylib*   MFServiceEx.dylib*       PreferenceLoader.plist   patcyh.dylib@
  MFAccelerator.plist*   MFServiceEx.plist*       RHRevealLoader.dylib*    patcyh.plist
  MFHongbaoRobot.dylib*  MobileSafety.dylib*      RHRevealLoader.plist
  MFHongbaoRobot.plist*  MobileSafety.plist       RocketBootstrap.dylib@
  MFService.bundle/      MyFirstReProject.dylib*  RocketBootstrap.plist

4.safe mode

因为APP程序质量参差不齐崩溃再所难免，tweak本质是dylib，寄生在别人进程里，如果注入Springboard等。
系统进程一旦出错，可能导致整个进程崩溃,崩溃后就会造成iOS瘫痪。
所以CydiaSubstrate引入了安全模式,在安全模式下所有基于CydiaSubstratede 的三方dylib都会被禁用，便于查错与修复。

建议：

ssh到iPhone
dpkg -r com.iosre.myfirstreprojec 可以删除对应的Tweak插件包

12. Tweak练习

1.定位目标文件

ps方法

  ps -e | grep WeChat

find方法
```
find -name sshd
```

固定目录中查找

AppStore App全部位于“/var/mobile/Containers/Bundle/Application/”下，
系统App全部位于“/Applications/”下

daemon的配置文件均位于
“/System/Library/LaunchDaemons/”
“/Library/LaunchDaemons”
“/Library/LaunchAgents/”

是一个plist格式的文件。其中的“ProgramArguments”字段，即是daemon可执行文件的绝对路径
  Flongers-iphone:/Library/LaunchDaemons root# cat com.openssh.sshd.plist 
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">

<dict>
    <key>Label</key>
    <string>com.openssh.sshd</string>

    <key>Program</key>
    <string>/usr/libexec/sshd-keygen-wrapper</string>

    <key>ProgramArguments</key>
    <array>
        <string>/usr/sbin/sshd</string>
        <string>-i</string>
    </array>

    <key>SessionCreate</key>
    <true/>

    <key>Sockets</key>
    <dict>
        <key>Listeners</key>
        <dict>
            <key>SockServiceName</key>
            <string>ssh</string>
        </dict>
    </dict>

    <key>StandardErrorPath</key>
    <string>/dev/null</string>

    <key>inetdCompatibility</key>
    <dict>
        <key>Wait</key>
        <false/>
    </dict>
</dict>

</plist>

2.获取头文件信息和bundleid

砸壳
通过class-dump获取头文件
获取bundleid
```
codesign -dvvv WeChat
```

3.分析头文件编写tweak代码

Makefile文件

THEOS_DEVICE_IP = 192.168.1.113
DEBUG = 1
ARCHS = armv7 arm64 
TARGET = iphone:latest:8.0  
include $(THEOS)/makefiles/common.mk

TWEAK_NAME = WeChatReProject
WeChatReProject_FILES = Tweak.xm
WeChatReProject_FRAMEWORKS = UIKit 
include $(THEOS_MAKE_PATH)/tweak.mk

after-install::
    install.exec "killall -9 WeChat"

clean::
    rm -rf ./packages/*