在 mac osx 使用 Il2CppDumper 遇到的坑

Perfare大神的Il2CppDumper支援 .NET Core了!

Intro

最近研究reverse，剛好之前有看過unity遊戲的逆向

很久以前連組語都看不太懂，亂逆一通，想說再重新玩玩看，練練手

剛好發現Il2CppDumper更新了! 因為我用的是mac osx，

所以決定將新版Il2CppDumper 在mac上compile一次，這樣就不用開vm了！

配置與所需資源

• My mac osx is v10.15.4
  • 其他版本與linux不確定，但理論上支援NET Core都應該可用
• .NET Core v3.1.404 (不是.NET喔)
  • .NET Core
• mono v6.12.0.107
  • Download Mono (stable channel)
• Il2CppDumper v6.4.19 (or higher) source code
  • Download source code

坑

一開始開開心心的把netcore裝好，source code載好

就滿懷期待的cd進Il2CppDumper然後

dotnet build --runtime osx-x64

結果直接報錯….

The reference assemblies for framework ".NETFramework,Version=v4.7.2" were not found

由於完全沒搞C#的經驗，根本看不懂這是什麼問題…

所以想說那就照他講的，安裝.NETFramework吧，但一查，怎麼沒mac osx的載點…

mac根本不能直裝…

解法

後來終於在這找到了類似問題的解決方法

先下載最新的mono，再將.csproj檔的開頭處加上:

<Import Project="netfx.props" />

所以Il2CppDumper.csproj看起來會長這樣

<Project Sdk="Microsoft.NET.Sdk">
<Import Project="netfx.props" />
  <PropertyGroup>
  以下省略
  ...

在csproj的同一目錄下，touch netfx.props

寫入以下內容:

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information. -->
<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <!-- When compiling .NET SDK 2.0 projects targeting .NET 4.x on Mono using 'dotnet build' you -->
    <!-- have to teach MSBuild where the Mono copy of the reference asssemblies is -->
    <TargetIsMono Condition="$(TargetFramework.StartsWith('net4')) and '$(OS)' == 'Unix'">true</TargetIsMono>
    
    <!-- Look in the standard install locations -->
    <BaseFrameworkPathOverrideForMono Condition="'$(BaseFrameworkPathOverrideForMono)' == '' AND '$(TargetIsMono)' == 'true' AND EXISTS('/Library/Frameworks/Mono.framework/Versions/Current/lib/mono')">/Library/Frameworks/Mono.framework/Versions/Current/lib/mono</BaseFrameworkPathOverrideForMono>
    <BaseFrameworkPathOverrideForMono Condition="'$(BaseFrameworkPathOverrideForMono)' == '' AND '$(TargetIsMono)' == 'true' AND EXISTS('/usr/lib/mono')">/usr/lib/mono</BaseFrameworkPathOverrideForMono>
    <BaseFrameworkPathOverrideForMono Condition="'$(BaseFrameworkPathOverrideForMono)' == '' AND '$(TargetIsMono)' == 'true' AND EXISTS('/usr/local/lib/mono')">/usr/local/lib/mono</BaseFrameworkPathOverrideForMono>

    <!-- If we found Mono reference assemblies, then use them -->
    <FrameworkPathOverride Condition="'$(BaseFrameworkPathOverrideForMono)' != '' AND '$(TargetFramework)' == 'net45'">$(BaseFrameworkPathOverrideForMono)/4.5-api</FrameworkPathOverride>
    <FrameworkPathOverride Condition="'$(BaseFrameworkPathOverrideForMono)' != '' AND '$(TargetFramework)' == 'net451'">$(BaseFrameworkPathOverrideForMono)/4.5.1-api</FrameworkPathOverride>
    <FrameworkPathOverride Condition="'$(BaseFrameworkPathOverrideForMono)' != '' AND '$(TargetFramework)' == 'net452'">$(BaseFrameworkPathOverrideForMono)/4.5.2-api</FrameworkPathOverride>
    <FrameworkPathOverride Condition="'$(BaseFrameworkPathOverrideForMono)' != '' AND '$(TargetFramework)' == 'net46'">$(BaseFrameworkPathOverrideForMono)/4.6-api</FrameworkPathOverride>
    <FrameworkPathOverride Condition="'$(BaseFrameworkPathOverrideForMono)' != '' AND '$(TargetFramework)' == 'net461'">$(BaseFrameworkPathOverrideForMono)/4.6.1-api</FrameworkPathOverride>
    <FrameworkPathOverride Condition="'$(BaseFrameworkPathOverrideForMono)' != '' AND '$(TargetFramework)' == 'net462'">$(BaseFrameworkPathOverrideForMono)/4.6.2-api</FrameworkPathOverride>
    <FrameworkPathOverride Condition="'$(BaseFrameworkPathOverrideForMono)' != '' AND '$(TargetFramework)' == 'net47'">$(BaseFrameworkPathOverrideForMono)/4.7-api</FrameworkPathOverride>
    <FrameworkPathOverride Condition="'$(BaseFrameworkPathOverrideForMono)' != '' AND '$(TargetFramework)' == 'net471'">$(BaseFrameworkPathOverrideForMono)/4.7.1-api</FrameworkPathOverride>
    <FrameworkPathOverride Condition="'$(BaseFrameworkPathOverrideForMono)' != '' AND '$(TargetFramework)' == 'net472'">$(BaseFrameworkPathOverrideForMono)/4.7.2-api</FrameworkPathOverride>
    <EnableFrameworkPathOverride Condition="'$(BaseFrameworkPathOverrideForMono)' != ''">true</EnableFrameworkPathOverride>

    <!-- Add the Facades directory.  Not sure how else to do this. Necessary at least for .NET 4.5 -->
    <AssemblySearchPaths Condition="'$(BaseFrameworkPathOverrideForMono)' != ''">$(FrameworkPathOverride)/Facades;$(AssemblySearchPaths)</AssemblySearchPaths>
  </PropertyGroup>
</Project>

現在，就可以開心的dotnet build --runtime osx-x64囉！

同理linux的--runtime就改個linux-x64即可

build完後可以在Debug/netcoreapp3.1/osx-64中使用Il2CppDumper了!

usage: ./Il2CppDumper <executable-file> <global-metadata>

後記與閒聊

完全沒搞過C#，不會配置，網路上教學也少(至少我找不到)，這篇主要是分享給跟我一樣的新手

同是天涯淪落人XD