记录学习Protobuf历程，最终实现App与本地Python服务器交互

希望这篇文章对你有帮助，可以减轻入门protobuf的一些负担~

目标:
1.搭建window & Nexus6P(Kali NetHunter) 运行gRPC环境 ps:Nexus6P环境的搭建可有可无~
2.使用Python gRPC 实现: 客户端服务端的protobuf的通信
3.PC上 client.py 移植到Nexus6P (Kali NetHunter) 上实现 android 与服务端(PC)交互 (ps:啥Android啊那就是Linux.... 可有可无)
4.r0env2022 搭建 Android app 运行服务端环境 & 编译apk....案例Dem0可直接在r0env2022下编译运行,只需要提取出.proto文件生成服务端代码就可直接使用，节省了时间
5.拦截AndroidDem0 PC 上 Python实现的服务端的通信&反序列化

与宿主机隔离开发环境

1.使用 virtualenv 创建一个船新的Python310 的环境virtualenv Python310_LearningProtobuf

◆先执行pip3 install virtualenv -i https://pypi.douban.com/simple再执行pip3 install virtualenvwrapper-win -i https://pypi.douban.com/simple

◆创建Python虚拟环境存放目录,D:\Interpreter installation Directory\virtualenv并加入系统环境PATH中

◆创建虚拟环境mkvirtualenv Py310protobuf并进入虚拟环境中...

2.虚拟环境安装protobufgrpcio grpcio-tools pip3 install protobuf grpcio grpcio-tools -i https://pypi.douban.com/simple

◆查看虚拟环境中第三方库及版本

什么是grpc & Protobuf？

◆gRPC是一种高性能、开源的远程过程调用（Remote Procedure Call，简称RPC）框架。它由Google开发并开源，旨在解决分布式系统中不同服务之间的通信问题。gRPC基于HTTP/2协议进行通信，并使用Protocol Buffers（简称Protobuf）作为默认的数据序列化和传输格式。

◆Protocol Buffers（protobuf）是一种轻量级、高效的数据序列化机制，也是Google开源的项目。它能够将结构化的数据序列化为二进制格式，以便在不同的系统之间进行数据交换。相比于JSON或XML等常见的文本格式，Protobuf产生的数据体积更小，序列化和反序列化速度更快。

◆gRPC使用Protobuf作为默认的消息传递格式，通过定义接口和消息类型来描述服务和数据格式，然后自动生成客户端和服务器端的代码。这样可以方便地进行跨语言的服务通信，提供了强大的代码生成能力和易于扩展的特性。gRPC支持多种编程语言，包括C++、Java、Python、Go、Ruby等。

◆总而言之，gRPC是一个基于HTTP/2和Protobuf的高性能RPC框架，它提供了简单、可靠的通信方式，使得分布式系统中的不同服务之间能够高效地进行数据交互。

◆Protobuf Github（https://github.com/protocolbuffers/protobuf/tree/main/python）

◆ Protobuf Python 文档（https://protobuf.dev/getting-started/pythontutorial/）

Python gRPC Protobuf正向开发实现PC Client Server 交互

1.创建 example.proto 文件来编写对应规则,创建了一个服务以及两个数据格式。

syntax = "proto3"; package test; service HelloDemo {    rpc Hello(HelloReq) returns(HelloReply){}} message HelloReq{    string name = 1;    int32 age = 2;    string sendtime = 3;} message HelloReply{    string result = 1;}

2.利用 example.proto 通过 grpcio_tools protoc 来生成Python 客户端和服务端(grpc-server)文件为踩坑记录。

python -m grpcio_tools -I. --python_out=. --grpc_python_out=. example.proto 失败 ,原因-> 猜测应该使用./ 来表示当前目录~

换一种方式,使用文档中提供的方式 protoc github download （https://github.com/protocolbuffers/protobuf/releases/tag/v23.4）下载之后加入到PATH中。

protoc -I=. --python_out=. --grpc_python_out=. example.proto 对example进行编译并生成 python客户端和服务端grpc代码。

but 又又又又报错了原因不可知也。

最后,执行 python -m grpc_tools.protoc -I./ --python_out=./ --grpc_python_out=./ example.proto 生成了两份代码。

3.根据生成的example_pb2_grpc.py编写 service.py。

# coding:utf-8 import grpcimport example_pb2 as pb2import example_pb2_grpc as pb2_grpcfrom concurrent import futures    # 目的为了给服务器增加线程 # HelloDemo 为 .proto 文件中 serviceclass HelloDemo(pb2_grpc.HelloDemoServicer):    # Hello 为  .proto 文件中 service 包含 rpc 方法名    def Hello(self, request, context):        name, age, sendtime = request.name, request.age, sendtime        result = f"My Name is {name},age is {age} years old!\n now time is {sendtime}"        # 返回数据类型为.proto 文件中 message   HelloReply        return pb2.HelloReply(result=result)  def run():    grpc_server = grpc.server(        futures.ThreadPoolExecutor(max_workers=4),    )


    
    pb2_grpc.add_HelloDemoServicer_to_server(HelloDemo(),grpc_server)    # PC 上 监听 127.0.0.1 局域网连接 监听 0.0.0.0    ip_port = "127.0.0.1:5505"    grpc_server.add_insecure_port(ip_port)    grpc_server.start()    print(f"service start at {ip_port}")    grpc_server.wait_for_termination() if __name__ == "__main__":    run()

4.根据生成的example_pb2.py 编写client.py。

# coding:utf-8 import grpcimport example_pb2 as pb2import example_pb2_grpc as pb2_grpcfrom concurrent import futures def run():    # 构建通道与服务器连接    conn = grpc.insecure_channel("127.0.0.1:5505")    # HelloDemoStub表示客户端  ,HelloDemoStub是 protoc 自动生成的    client = pb2_grpc.HelloDemoStub(channel=conn)    name, age, sendtime = "xiaozhu0513", 18, datetime.now().strftime('%Y-%m-%d-%H:%M:%S')    # 相当于先生成一个 HelloReq 类型的数据  为 本地发送到客户端的数据, 然后传输  实例化客户端的    response = client.Hello(pb2.HelloReq(        name = name,        age = age,        sendtime = f"{sendtime}"    ))    print(f"客户端发送 {name} {age} {sendtime} -> 服务器")    print("客户端接收到服务器返回信息 ",response.result)  if __name__ == "__main__":    run()

5.先运行service.py 再运行 client.py 效果图如下：

6.至此,完成了第一个小任务,最后查阅资料时,发现官方提供了Demo 以及教程....

官方demo（https://grpc.io/docs/languages/python/quickstart/）

client.py（https://github.com/grpc/grpc/blob/master/examples/python/helloworld/greeter_client.py）

service.py（https://github.com/grpc/grpc/blob/master/examples/python/helloworld/greeter_server.py）

常用的protobuf数据类型&特殊字符&pb文件&

官方语法介绍（https://protobuf.dev/programming-guides/proto3/）

常用的protobuf数据类型

1.string -> 字符串类型，要求utf-8或7-bit 与 ascii编码的字符串

2.bytes -> 比特类型

3.bool -> 布尔类型

4.int32 ->32位整形对应Py是int

5.int64 ->64位整形对应Py是int

6.float -> 浮点类型

7.repeated -> 数组 (list) 如 repeated string data = 1; 表示一个 string 的list

8.map -> 字典类型(Python) 如map data = 1; 前者为key的string类型后者为string类型的value

常用的protobuf特殊字符

1.package -> 包名

2.syntax -> Protobuf语法版本

3.service -> 定义一个服务

4.rpc -> 定义服务中的方法

5.stream -> 定义方法的传输为流传输

6.message -> 定义消息体 message User{}

7.extend -> 扩展消息体 extend User{}

8.import -> 导入一些插件

9.// -> 注释~

在Nexus6P KaliNetHunter 上配置环境并启动客户端与PC上server进行通信 (可有可无....)

目标：

1.在6P手机上配置好Python环境,grpc环境
2.运行client.py 与 PC上server.py进行交互
3.(未复现出)抓包拦截请求数据,尝试分析....当初以为只要运行在手机上就算是android了,,,后来才反应过来,,,,我是运行在linux上py程序不是android

Nexus6P手机上配置grpc环境~

1.Python3.10 环境下直接安装三件套pip3 install protobuf grpcio grpcio-tools -i https://pypi.douban.com/simple。

2.下载linux对应的 protoc 工具 push到手机内. 先不下载试试win生成的两份_pb2文件能否共用 ? 是的,可直接可用。

3.将client.py 修改访问地址为局域网内PC的ip 并push到 /sdcard/protobuf 目录下。

Nexus6P 与PC 通信

将服务端的监听端口由127.0.0.1 修改为 0.0.0.0,之后先启动server 再在6P手机上启动client.Py 实现交互

可以发现同一局域网时可以进行通信的。

此处采用中间人抓包会报错

客户端启动失败！charles 抓的包为 Unknow 整体运行逻辑如下~

◆不知为何原因~

Android grpc-protobuf Dem0

demo下载地址（https://github.com/xuexiangjys/Protobuf-gRPC-Android）

目标：
1.实现Android App 与 PC上建立的Python服务端进行通信
2.弄清楚普通i请求grpc 的执行流程以及生成对应的Python服务器版本代码
3.最终实现效果可以使得二者可以正常通信，为抓包hook以及分析打下基础

搞清楚 android-java .proto 的运行原理

1.Java客户端 + Python后端实现通信（https://blog.51cto.com/u_15895329/5894299）

2.官方Java教程官方Python教程（https://protobuf.dev/getting-started/pythontutorial/）

利用Demo 实现与Python 通信

只分析其中一个界面

找到demo中helloworle.proto文件 pull到PC上并生成Python _pb2_grpc.py 代码

◆进入对应解释器环境下执行python -m grpc_tools.protoc -I./ --python_out=./ --grpc_python_out=./ helloworld.proto

◆照猫画虎写出对应的service.py

from datetime import datetime import grpcimport helloworld_pb2 as pb2import helloworld_pb2_grpc as pb2_grpcfrom concurrent import futures class Greeter(pb2_grpc.GreeterServicer):    def SayHello(self, request, context):        name = request.name        sendtime = datetime.now().strftime('%Y-%m-%d-%H:%M:%S')        result = f"My Name is {name}!!! send time is {sendtime} "        print(f"服务器接收到客户端参数 -> name = {name}")        print(f"服务器响应时间: {sendtime}")        return pb2.HelloReply(message = result)  def run():    grpc_server = grpc.server(        futures.ThreadPoolExecutor(max_workers=4),    )    pb2_grpc.add_GreeterServicer_to_server(Greeter(),grpc_server)    # ip_port = "127.0.0.1:50051"    ip_port = "0.0.0.0:50051"    grpc_server.add_insecure_port(ip_port)    grpc_server.start()    print(f"service start at {ip_port}")    grpc_server.wait_for_termination() if __name__ == "__main__":    run()

◆验证启动apk 能否正常通信

所有所有前期准备已经ok 准备使用hook抓包看能否抓到包~

objection动态分析 & Hook socket抓包

1.objection 动态分析, 搜索类 android hooking search classes protobuf

◆复制系统库保存为txt文件执行脚本加上hook

# 读取文件并处理
with open('my_protobuf.txt', 'r',encoding='utf-8') as file:
    lines = file.readlines()
    processed_lines = []
    for line in lines:
        # 进行处理操作
        processed_line = "android hooking watch class " + line
        # 将处理后的行插入到原来的列表中
        processed_lines.append(processed_line)

# 将处理后的内容按行插入到原文件中
with open('my_protobuf_new.txt', 'w',encoding='utf-8') as file:
    for processed_line in processed_lines:
        file.write(processed_line)

2.所有的输出信息如下：

com.xuexiang.protobufdemo on (google: 8.1.0) [usb] # (agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.toBuilder()(agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.dynamicMethod(com.google.protobuf.GeneratedMessageLite$MethodToInvoke)                                                                                         (agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.dynamicMethod(com.google.protobuf.GeneratedMessageLite$MethodToInvoke)                                                                                         (agent) [33h1vvf01vb] Called com.google.protobuf.UnknownFieldSetLite.getDefaultInstance()(agent) [r44a6fapyp] Called com.google.protobuf.GeneratedMessageLite$Builder.mergeFrom(com.google.protobuf.GeneratedMessageLite)                                                                                                     (agent) [r44a6fapyp] Called com.google.protobuf.GeneratedMessageLite$Builder.copyOnWrite()(agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.visit(com.google.protobuf.GeneratedMessageLite$Visitor, com.google.protobuf.GeneratedMessageLite)                                                              (agent) [flxqngw0jns] Called com.google.protobuf.GeneratedMessageLite$MergeFromVisitor.visitString(boolean, java.lang.String, boolean, java.lang.String)                                                                             (agent) [flxqngw0jns] Called com.google.protobuf.GeneratedMessageLite$MergeFromVisitor.visitUnknownFields(com.google.protobuf.UnknownFieldSetLite, com.google.protobuf.UnknownFieldSetLite)                                          (agent) [33h1vvf01vb] Called com.google.protobuf.UnknownFieldSetLite.getDefaultInstance()(agent) [r44a6fapyp] Called com.google.protobuf.GeneratedMessageLite$Builder.copyOnWrite()(agent) [r44a6fapyp] Called com.google.protobuf.GeneratedMessageLite$Builder.build()(agent) [r44a6fapyp] Called com.google.protobuf.GeneratedMessageLite$Builder.buildPartial()(agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.makeImmutable()(agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.dynamicMethod(com.google.protobuf.GeneratedMessageLite$MethodToInvoke)                                                                                         (agent) [33h1vvf01vb] Called com.google.protobuf.UnknownFieldSetLite.makeImmutable()(agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.isInitialized()(agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.dynamicMethod(com.google.protobuf.GeneratedMessageLite$MethodToInvoke, java.lang.Object)                                                                       (agent) [4fnnhkno676] Called io.grpc.protobuf.lite.ProtoLiteUtils$MessageMarshaller.stream(java.lang.Object)(agent) [4fnnhkno676] Called io.grpc.protobuf.lite.ProtoLiteUtils$MessageMarshaller.stream(com.google.protobuf.MessageLite)                                                                                                          (agent) [t74uyknf3ri] Called io.grpc.protobuf.lite.ProtoInputStream.available()(agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.computeStringSize(int, java.lang.String)(agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.computeTagSize(int)(agent) [75uwxvix9zw] 【【【Called com.google.protobuf.WireFormat.makeTag(int, int)】】】(agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.computeUInt32SizeNoTag(int)(agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.computeStringSizeNoTag(java.lang.String)(agent) [78m3ko66u48] Called com.google.protobuf.Utf8.encodedLength(java.lang.CharSequence)(agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.computeLengthDelimitedFieldSize(int)(agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.computeUInt32SizeNoTag(int)


    
(agent) [t74uyknf3ri] Called io.grpc.protobuf.lite.ProtoInputStream.drainTo(java.io.OutputStream)(agent) [pi8dc23shb] 【【【Called com.google.protobuf.AbstractMessageLite.writeTo(java.io.OutputStream)】】】(agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.computePreferredBufferSize(int)(agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.newInstance(java.io.OutputStream, int)(agent) [2ira22725rq] Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeString(int, java.lang.String)                                                                                                            (agent) [2ira22725rq] Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeTag(int, int)(agent) [75uwxvix9zw] 【【【Called com.google.protobuf.WireFormat.makeTag(int, int)】】】(agent) [2ira22725rq] Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeUInt32NoTag(int)(agent) [2ira22725rq] Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.flushIfNotAvailable(int)(agent) [032rofd4w0eb] Called com.google.protobuf.CodedOutputStream$AbstractBufferedEncoder.bufferUInt32NoTag(int)(agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.access$100()(agent) [2ira22725rq] Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeStringNoTag(java.lang.String)                                                                                                            (agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.computeUInt32SizeNoTag(int)(agent) [78m3ko66u48] 【【【Called com.google.protobuf.Utf8.encode(java.lang.CharSequence, [B, int, int)】】】(agent) [yozcy0715w] Called com.google.protobuf.Utf8$SafeProcessor.encodeUtf8(java.lang.CharSequence, [B, int, int)(agent) [2ira22725rq] Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeUInt32NoTag(int)(agent) [2ira22725rq] Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.flushIfNotAvailable(int)(agent) [032rofd4w0eb] Called com.google.protobuf.CodedOutputStream$AbstractBufferedEncoder.bufferUInt32NoTag(int)(agent) [4gz3lfvhznc] Called com.google.protobuf.CodedOutputStream.access$100()(agent) [2ira22725rq] Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeLazy([B, int, int)(agent) [2ira22725rq] 【【【Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.write([B, int, int)】】】(agent) [2ira22725rq] Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.flush()(agent) [2ira22725rq] Called com.google.protobuf.CodedOutputStream$OutputStreamEncoder.doFlush()(agent) [4fnnhkno676] Called io.grpc.protobuf.lite.ProtoLiteUtils$MessageMarshaller.parse(java.io.InputStream)(agent) [4fnnhkno676] Called io.grpc.protobuf.lite.ProtoLiteUtils$MessageMarshaller.parse(java.io.InputStream)(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.newInstance([B, int, int)(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.newInstance([B, int, int, boolean)(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.pushLimit(int)(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.recomputeBufferSizeAfterLimit()(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.setSizeLimit(int)(agent) [4fnnhkno676] Called io.grpc.protobuf.lite.ProtoLiteUtils$MessageMarshaller.parseFrom(com.google.protobuf.CodedInputStream)                                                                                                  (agent) [6thpuwhq0js] Called com.google.protobuf.AbstractParser.parseFrom(com.google.protobuf.CodedInputStream, com.google.protobuf.ExtensionRegistryLite)                                                                           (agent) [6thpuwhq0js] Called com.google.protobuf.AbstractParser.parseFrom(com.google.protobuf.CodedInputStream, com.google.protobuf.ExtensionRegistryLite)                                                                           (agent) [b7ksjxdkr9] Called com.google.protobuf.GeneratedMessageLite$DefaultInstanceBasedParser.parsePartialFrom(com.google.protobuf.CodedInputStream, com.google.protobuf.ExtensionRegistryLite)                                    (agent) [b7ksjxdkr9] Called com.google.protobuf.GeneratedMessageLite$DefaultInstanceBasedParser.parsePartialFrom(com.google.protobuf.CodedInputStream, com.google.protobuf.ExtensionRegistryLite)                                    (agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.parsePartialFrom(com.google.protobuf.GeneratedMessageLite, com.google.protobuf.CodedInputStream, com.google.protobuf.ExtensionRegistryLite)                    (agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.dynamicMethod(com.google.protobuf.GeneratedMessageLite$MethodToInvoke)                                                                                         (agent) [33h1vvf01vb] Called com.google.protobuf.UnknownFieldSetLite.getDefaultInstance()(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.readTag()(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.isAtEnd()(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.readRawVarint32()


    
(agent) [75uwxvix9zw] Called com.google.protobuf.WireFormat.getTagFieldNumber(int)(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.readStringRequireUtf8()(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.readRawVarint32()(agent) [78m3ko66u48] Called com.google.protobuf.Utf8.isValidUtf8([B, int, int)(agent) [sa0emcwxaha] Called com.google.protobuf.Utf8$Processor.isValidUtf8([B, int, int)(agent) [yozcy0715w] Called com.google.protobuf.Utf8$SafeProcessor.partialIsValidUtf8(int, [B, int, int)(agent) [yozcy0715w] Called com.google.protobuf.Utf8$SafeProcessor.partialIsValidUtf8([B, int, int)(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.readTag()(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.isAtEnd()(agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.tryRefillBuffer(int)(agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.makeImmutable()(agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.dynamicMethod(com.google.protobuf.GeneratedMessageLite$MethodToInvoke)                                                                                         (agent) [33h1vvf01vb] Called com.google.protobuf.UnknownFieldSetLite.makeImmutable()(agent) [6thpuwhq0js] Called com.google.protobuf.AbstractParser.checkMessageInitialized(com.google.protobuf.MessageLite)                                                                                                             (agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.isInitialized()(agent) [e48kca70yae] Called com.google.protobuf.GeneratedMessageLite.dynamicMethod(com.google.protobuf.GeneratedMessageLite$MethodToInvoke, java.lang.Object)                                                                       (agent) [34xbsz3uxgl] Called com.google.protobuf.CodedInputStream.checkLastTagWas(int)