(Linux) .so hooking

#define _GNU_SOURCE

#include<dlfcn.h>
#include<stdio.h>

typedef int(*orig_getchar_ftype)(void);

int getchar(){
        orig_getchar_ftype orig_getchar;
        orig_getchar = (orig_getchar_ftype)dlsym(RTLD_NEXT, "getchar");
        puts("hooked success!!");
        return orig_getchar();
}

 

sudo gcc -o hook.so -fPIC --shared hook.c

 

#include<stdio.h>

int main(){
    getchar();
    return 0;
}

 

export LD_PRELOAD=/path *절대 경로

 

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https://umbum.tistory.com/128

LD_PRELOAD를 이용한 so injection과 hooking. + wrapping function

https://asung123456.tistory.com/18

Linux C/C++ shared library 컴파일하기 fPIC 옵션 GOT, PLT

https://www.tcpschool.com/c/c_pointer_intro

코딩교육 티씨피스쿨