为什么写这篇笔记

最近在学习分析so的使用，发现目标的so文件是进行过处理的，直接打开so文件里面什么都看不到，基本的so文件都缺少了好几块文件，最主要的是字符串是动态加密的，用到时解密，使用完成后就销毁。为了获取能静态分析的so文件(在ida上能大致看一些伪代码)，就需要将手机内存中的so文件进行dump下来。

使用ida进行dump

刚开始的时候尝试使用ida脚本进行dump，但是dump出来的so文件还是不全，可能是没有进行修复的原因，分析的过程中非常难受，基本上都是在使用ida动态调试的过程中去看，这样效率太低，使用frida去hook想验证的函数时，又需要进行绝对地址和相对地址的计算，并且so调试过程中经常崩溃。当然，使用ida进行dump是一种方式，只是我不懂修复dump出来的so文件。

python脚本

ida脚本

使用frida_dump进行dump so文件

后面实在分析不出下去了，问导师dump的脚本，我本意是ida的dump脚本是怎么写的，导师说他用frida_dump,挖槽，原来导师没有遇到问题不是使用ida进行dump啊，于是导师给我发了frida_dump的git地址，我使用该工具dump出来的文件确实是比我使用ida弄出来的文件大了不少。

如何使用frida_dump作者写的很清楚，我在这贴一下相关的文档。

1. dump android module
usage:
​ python dump_so.py

​ python dump_so.py so_name

➜  frida_dump git:(master) ✗ python dump_so.py libc.so              
{'name': 'libc.so', 'base': '0xf2282000', 'size': 819200, 'path': '/apex/com.android.runtime/lib/bionic/libc.so'}
android/SoFixer32: 1 file pushed. 5.9 MB/s (91848 bytes in 0.015s)
libc.so.dump.so: 1 file pushed. 21.4 MB/s (819200 bytes in 0.036s)
adb shell /data/local/tmp/SoFixer -m 0xf2282000 -s /data/local/tmp/libc.so.dump.so -o /data/local/tmp/libc.so.dump.so.fix.so
[main_loop:87]start to rebuild elf file
[Load:69]dynamic segment have been found in loadable segment, argument baseso will be ignored.
[RebuildPhdr:25]=============LoadDynamicSectionFromBaseSource==========RebuildPhdr=========================
[RebuildPhdr:37]=====================RebuildPhdr End======================
[ReadSoInfo:549]=======================ReadSoInfo=========================
[ReadSoInfo:696]soname 
[ReadSoInfo:699]Unused DT entry: type 0x6ffffffb arg 0x00000001
[ReadSoInfo:599] rel (DT_REL) found at 15f20
[ReadSoInfo:603] rel_size (DT_RELSZ) 1703
[ReadSoInfo:699]Unused DT entry: type 0x6ffffffa arg 0x000005f5
[ReadSoInfo:591] plt_rel (DT_JMPREL) found at 19458
[ReadSoInfo:595] plt_rel_count (DT_PLTRELSZ) 617
[ReadSoInfo:584]symbol table found at 32ac
[ReadSoInfo:580]string table found at 10e58
[ReadSoInfo:699]Unused DT entry: type 0x6ffffef5 arg 0x0000a98c
[ReadSoInfo:629] constructors (DT_INIT_ARRAY) found at b5954
[ReadSoInfo:633] constructors (DT_INIT_ARRAYSZ) 4
[ReadSoInfo:637] destructors (DT_FINI_ARRAY) found at b3000
[ReadSoInfo:641] destructors (DT_FINI_ARRAYSZ) 2
[ReadSoInfo:699]Unused DT entry: type 0x6ffffff0 arg 0x00009b4c
[ReadSoInfo:699]Unused DT entry: type 0x6ffffffc arg 0x0000a860
[ReadSoInfo:699]Unused DT entry: type 0x6ffffffd arg 0x00000009
[ReadSoInfo:699]Unused DT entry: type 0x6ffffffe arg 0x0000a95c
[ReadSoInfo:699]Unused DT entry: type 0x6fffffff arg 0x00000001
[ReadSoInfo:703]=======================ReadSoInfo End=========================
[RebuildShdr:42]=======================RebuildShdr=========================
[RebuildShdr:536]=====================RebuildShdr End======================
[RebuildRelocs:783]=======================RebuildRelocs=========================
[RebuildRelocs:809]=======================RebuildRelocs End=======================
[RebuildFin:709]=======================try to finish file rebuild =========================
[RebuildFin:733]=======================End=========================
[main:123]Done!!!
/data/local/tmp/libc.so.dump.so.fix.so: 1 file pulled. 29.0 MB/s (819882 bytes in 0.027s)
libc.so_0xf2282000_819200_fix.so
2. dump android dex
frida -U --no-pause -f packagename  -l dump_dex.js
     ____
    / _  |   Frida 12.4.8 - A world-class dynamic instrumentation toolkit
   | (_| |
    > _  |   Commands:
   /_/ |_|       help      -> Displays the help system
   . . . .       object?   -> Display information about 'object'
   . . . .       exit/quit -> Exit
   . . . .
   . . . .   More info at http://www.frida.re/docs/home/
Spawned `packagename`. Resuming main thread!
[Google Pixel XL::packagename]-> [dlopen:] libart.so
_ZN3art11ClassLinker11DefineClassEPNS_6ThreadEPKcmNS_6HandleINS_6mirror11ClassLoaderEEERKNS_7DexFileERKNS9_8ClassDefE 0x7ac6dc4f74
[DefineClass:] 0x7ac6dc4f74
[dump dex]: /data/data/packagename/files/7aab800000_8341c4.dex
Thanks