这是我参与8月更文挑战的第22天，活动详情查看： 8月更文挑战” juejin.cn/post/698796… ”

前言

These are some of the existing methods to implement IPC on iOS:

• Universal Links、URL Scheme

kunnan.blog.csdn.net/article/det…

• Keychain

blog.csdn.net/z929118967/…

• UIDocumentInteractionController
• 利用socket进行本地通信

blog.csdn.net/z929118967/…

• Mach Ports
• Pasteboard

iOS 逆向：Tweak的开发例子【发红包】使用tweak和lua脚本结合进行实现 blog.csdn.net/z929118967/…

	UIPasteboard* pasteboard = [UIPasteboard generalPasteboard];	
	[pasteboard setString:@"A1"];
//使用tweak和lua脚本结合进行实现
//1、tweak侧的功能是hookapp的原生功能
//2、lua 是实现模拟用户点击
//3、通信通过剪切板：tweak 通过剪切板和lua脚本进行通信
//其实后面我继续研究，把lua侧的功能全部用tweak实现了。 这里分享的是一个思路。

• AppleEvents & AppleScript
• Distributed Objects
• XPC

developer.apple.com/library/con…

• Notifications

iphonedevwiki.net/index.php/N…

• libobjcipc

iphonedevwiki.net/index.php/L…

• LightMessaging

github.com/rpetrich/Li…

Community Libraries

• 1、RocketBootstrap： Service registration and lookup system for iOS
• 2、OBJCIPC ：High-level API for hosting services inside apps (by Alan Yip/a1anyip)
• 3、LightMessaging： Header-only library for simple IPC

本文重点讲解 RocketBootstrap的两种包装方式：CFMessagePort、CPDistributedMessagingCenter

I 、librocketbootstrap

• RocketBootstrap4Inter_process_Communication
• feature

1、Uses iOS7’s security model: Privileged processes can register, any process can look up 2、Works with existing mach-based IPC mechanisms 3、Similar to Apple’s bootstrap APIs: bootstrap_look_up becomes rocketbootstrap_look_up bootstrap_register becomes rocketbootstrap_register 4、Easy to use wrappers for CFMessagePort and CPDistributedMessagingCenter(todo: XPC) 5、Bring your own security model by using audit_token_to_au32 to know who’s calling 6、Requires package dependency, commonly installed on users’ devices

1.0 获取librocketbootstrap ：

-Install this from Cydia 直接搜索rocketbootstrap安装即可

iPhone:/var/log root# ls -l /usr/lib/librocketbootstrap.dylib
-rwxr-xr-x 1 root wheel 221776 Feb  6  2017 /usr/lib/librocketbootstrap.dylib*

/Library/LaunchDaemons/com.rpetrich.rocketbootstrapd.plist
/usr/libexec/rocketd
launchctl load  /Library/LaunchDaemons/com.rpetrich.rocketbootstrapd.plist
launchctl unload /Library/LaunchDaemons/com.rpetrich.rocketbootstrapd.plist

1.1 CFMessagePort

• registerMsgCenter 基本可以解决双向通信； 例子：避免重启其他进程从sb获取源地址信息的变更。 守护进行都可以注册成为服务

+ (kern_return_t)rockettest_messageport_server
{
    static CFMessagePortRef messagePort;//
    if (messagePort)
        return 0;
    messagePort = CFMessagePortCreateLocal(kCFAllocatorDefault, CFSTR("rockettest_messageport"), messagePortCallback, NULL, NULL);//CFSTR("rockettest_messageport")即server key,
    CFRunLoopSourceRef source = CFMessagePortCreateRunLoopSource(kCFAllocatorDefault, messagePort, 0);
    CFRunLoopAddSource(CFRunLoopGetCurrent(), source, kCFRunLoopCommonModes);
    CFRunLoopAddSource(CFRunLoopGetCurrent(), source, (CFStringRef)UITrackingRunLoopMode);
    return rocketbootstrap_cfmessageportexposelocal(messagePort);
}
typedef CFDataRef (*CFMessagePortCallBack)(CFMessagePortRef local, SInt32 msgid, CFDataRef data, void *info);
//回调的定义
static CFDataRef messagePortCallback(CFMessagePortRef local, SInt32 msgid, CFDataRef data, void *info)
{
    NSLog(@"rockettest_messageport_server: received %@", data);
    return CFDataCreate(kCFAllocatorDefault, (const UInt8 *)"bootstrap", 9);
}

• CFMessagePort: Only supports synchronous use

#import <UIKit/UIKit.h>
#include "log.h"

#import "rocketbootstrap.h"

@implementation NSObject (rocketbootstrap)

+ (kern_return_t)rocketbootstrap_unlock:(NSString *)name
{
	return rocketbootstrap_unlock([name UTF8String]);
}

static CFDataRef messagePortCallback(CFMessagePortRef local, SInt32 msgid, CFDataRef data, void *info)
{
	NSLog(@"rockettest_messageport_server: received %@", data);
	return CFDataCreate(kCFAllocatorDefault, (const UInt8 *)"bootstrap", 9);
}
/**
registerMsgCenter 基本可以解决双向通信；
例子：避免重启其他进程从sb获取源地址信息的变更。 守护进行都可以注册成为服务
*/
+ (kern_return_t)rockettest_messageport_server
{
	static CFMessagePortRef messagePort;
	if (messagePort)
		return 0;
	messagePort = CFMessagePortCreateLocal(kCFAllocatorDefault, CFSTR("rockettest_messageport"), messagePortCallback, NULL, NULL);
	CFRunLoopSourceRef source = CFMessagePortCreateRunLoopSource(kCFAllocatorDefault, messagePort, 0);
	CFRunLoopAddSource(CFRunLoopGetCurrent(), source, kCFRunLoopCommonModes);
	CFRunLoopAddSource(CFRunLoopGetCurrent(), source, (CFStringRef)UITrackingRunLoopMode);
	return rocketbootstrap_cfmessageportexposelocal(messagePort);
}

+ (NSData *)rockettest_messageport_client
{
	CFMessagePortRef remote = rocketbootstrap_cfmessageportcreateremote(kCFAllocatorDefault, CFSTR("rockettest_messageport"));
	if (!remote)
		return nil;
	CFDataRef request = CFDataCreate(kCFAllocatorDefault, (const UInt8 *)"rocket", 6);
	CFDataRef response = NULL;
	CFMessagePortSendRequest(remote, 0, request, 10, 10, CFSTR("rocketboostrap_wait"), &response);
	CFRelease(remote);
	CFRelease(request);
	return [(NSData *)response autorelease];
}

II CPDistributedMessagingCenter

Asynchronous, if you go through the trouble

2.1 CFMessagePort Example

• Server

static CFDataRef Callback(CFMessagePortRef port,
                          SInt32 messageID,
                          CFDataRef data,
                          void *info)
{
    // ...
}

%ctor {
    static CFMessagePortRef localPort =
        CFMessagePortCreateLocal(nil,
                                 CFSTR("com.example.app.port.server"),
                                 Callback,
                                 nil,
                                 nil);

    CFRunLoopSourceRef runLoopSource =
        CFMessagePortCreateRunLoopSource(nil, localPort, 0);

    CFRunLoopAddSource(CFRunLoopGetCurrent(),
                       runLoopSource,
                       kCFRunLoopCommonModes);

    rocketbootstrap_cfmessageportexposelocal(localPort);
}

• Client

void doStuff() {
    CFDataRef data;
    SInt32 messageID = 0x1111; // Arbitrary
    CFTimeInterval timeout = 10.0;

    CFMessagePortRef remotePort =
        rocketbootstrap_cfmessageportcreateremote(nil,
                                  CFSTR("com.example.app.port.client"));

    SInt32 status =
        CFMessagePortSendRequest(remotePort,
                                 messageID,
                                 data,
                                 timeout,
                                 timeout,
                                 NULL,
                                 NULL);

    if (status == kCFMessagePortSuccess) {
        // ...
    }
}

2.2 CPDistributedMessagingCenter的例子

目前发现这种方式只能在SpringBoard 注册为服务端，处理消息，；

进程间其实是单向通信;

#TweakDemo.xm  SpringBoard  接受消息
#import "rocketbootstrap.h"

#define kXPCCenterNameKey  @"kXPCCenterNameKey_83641"

%hook SpringBoard
- (void)applicationDidFinishLaunching:(id)application {
   %orig;
   CPDistributedMessagingCenter *c = [%c(CPDistributedMessagingCenter) centerNamed:kXPCCenterNameKey];
   rocketbootstrap_distributedmessagingcenter_apply(c);
   [c runServerOnCurrentThread];
   [c registerForMessageName:@"myMessageName" target:self selector:@selector(handleMessage:withUserInfo:)];
   NSLog(@"注册监听 start");
}

%new
- (void)handleMessage:(NSString *)name withUserInfo:(NSDictionary *)userInfo {
   NSLog(@"handleMessage withUserInfo:%@",userInfo);
   //TODO:something
}

%end
//在需要发送的地方(沙盒 app )，如此这般的写： 
%hook SomeClass

-(void)someMethod{
   %orig;
    NSMutableDictionary *userInfo = [@{} mutableCopy];
    [userInfo setObject:@"123" forKey:@"arg001"];
    [userInfo setObject:@"456" forKey:@"arg002"];
    NSLog(@"发送: %@=%@",kXPCCenterNameKey,userInfo);
    CPDistributedMessagingCenter *c = [%c(CPDistributedMessagingCenter) centerNamed:kXPCCenterNameKey];
    rocketbootstrap_distributedmessagingcenter_apply(c);
    [c sendMessageName:@"myMessageName" userInfo:userInfo];
}
%end

III、 UIPasteboard/NSPasteboard

OpenUDID的使用例子

#if TARGET_OS_IPHONE || TARGET_IPHONE_SIMULATOR
#import <UIKit/UIPasteboard.h>
#import <UIKit/UIKit.h>
#else
#import <AppKit/NSPasteboard.h>
#endif
#if TARGET_OS_IPHONE || TARGET_IPHONE_SIMULATOR
        UIPasteboard* slotPB = [UIPasteboard pasteboardWithName:slotPBid create:NO];
#else
        NSPasteboard* slotPB = [NSPasteboard pasteboardWithName:slotPBid];
#endif

• 利用 pasteboardWithName 方法进行数据存储达到通信的目的

/**
 应用级别的，数据在属于自己的应用内部共享；
 (默认情况下是不会把数据写进沙盒的，也就是说（复制、剪切）粘贴内容会因为应用的退出而销毁掉，我们可以设置相关属性 persistent值为 YES让其进行数据的持久化存储起来)
 
 Ps：例如 persistent 是否进行数据持久化 还有 changeCount 改变次数（剪切板）系统重启方才重新计数
 
 */
- (NSObject *)model{
    
    if (_model == nil) {
        
        NSString *contentUserID =@"";
        UIPasteboard *pasteboardUserID = [UIPasteboard pasteboardWithName:KNpasteboardWithNameKeyUserID create:NO];
        
        if (pasteboardUserID){
            contentUserID = pasteboardUserID.string;////获取内容
        }
        
        _model = [[NSObject alloc]init];
//        _model.UserId =contentUserID;
        
        
    }
    return _model;
}

IV、LightMessaging

• feature

1、Mid-level API, 2、Message-oriented 3、Zero copy, for certain message types 4、No additional cost over standard mach calls 5、Easy integration with RocketBootstrap 6、No package dependencies

• using

1、Start services with LMStartService 2、Send messages with LMConnectionSendTwoWay (and friends) 3、Send replies with LMSendReply (and friends) 4、Bring your own security checks still ：Community developers, your input on API please!

V 、IPC

allows processes to send each other messages and data

更多内容请看原文和关注公众号：iOS逆向

VI、libobjcipc

• feature

• High level API provides service lookup and IPC, easy to use • Background-launches and fakes app lifecycle for you • Message-oriented • Mostly asynchronous • “Open” security model • Requires separate package dependency, but very small • Simple Objective-C APIs: Register using --registerIncomingMessageFromAppHandlerForMessageName:handler: Send using -- sendMessageToAppWithIdentifier:messageName:dictionary:replyHandler:
• Similar patterns for App to SpringBoard

VII XPC

XPC can be accessed through either the libxpc C API, or the NSXPCConnection Objective-C API.

• feature

1、High level API, easy to use ：One of Apple’s many wrappers for Mach messages； 2、Message-oriented 3、Public API on OS X only 4、Asynchronous always, no synchronous versions 5、Service lookup is restricted on iOS 7+

VIII Tweaks on a multi-process iOS

• Inter-Process Communication

1、Mechanisms provided by the kernel to facilitate coordinated sharing of data and commands between processes
2、Used heavily in recent versions of iOS and OS X to implement system frameworks and APIs

• Standard Techniques

1、Save to temp files：High level APIs, easy to use
2、Unix Domain Sockets： Low level API  ，Stream oriented, requires basic parsing to reconstruct
messages

• Other standard techniques

• Shared Memory
• Signals
• Named pipes
• Network sockets 

• Apple/iOS-specific Techniques

1、Darwin Notifications：No data, only a simple “go” message，Any process can post or observe ，Always asynchronous
2、Mach Ports ：seriously low level 
3、CPDistributedNotificationCenter： Private API, does change between iOS versions
4、CFMessagePort： Public API，Only supports synchronous use ，Service lookup is restricted on iOS 6+
5、XPC ： High level API, easy to use �，One of Apple’s many wrappers for Mach messages ；

• Creative Techniques

1、Relax existing service permissions
2、Repurpose existing iOS services’ IPC channels：Service internals are frequently rewritten in new iOS versions
3、Delegate to someone else

• Libraries that use IPC under the hood

1、http://iphonedevwiki.net/index.php/AppList
2、http://iphonedevwiki.net/index.php/Flipswitch
3、http://iphonedevwiki.net/index.php/Libactivator
4、https://github.com/r-plus/libcanopenurl

• Community Libraries to Help

1、RocketBootstrap： Service registration and lookup system for iOS

• Be aware of potential deadlocks

1、 SpringBoard will block on backboardd—don’t call from backboardd to SpringBoard! 
2、Communicate with these processes using one-way IPC, asynchronous IPC, or two-way IPC with timeouts 
3、Avoid the pitfall of accidentally sending blocking API calls to one’s own process
4、SpringBoard is usually a good choice for coordinator as it often has much work to do anyway
5、Batch all of the operations for a single user action into one IPC call, if possible 
6、Filter to only the data required before sending 

IV、 see also

更多内容请看原文，或者关注公众号：iOS逆向