[C] Re-execute itself from elf file.

Posted 2020-08-11 Jeremy 學習筆記

Re-execute itself from elf file.

 

#define _GNU_SOURCE
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>

extern char **environ;

int main(int argc, char *argv[])
{
        char **ep;
        char *sh[] = {"/bin/sh", NULL};
        char me[256], *mee[] = {me, "hello", NULL};
        puts("hey~");
        //execve(*sh, sh, environ);

        if ( argc > 1 && strcmp(argv[1], "hello") == 0 ) {
                printf("argv[1] : %s\n", argv[1]);
                puts("from execve()...");
                return 0;
        }

        memset(me, 0, sizeof(me));
        readlink("/proc/self/exe", me, sizeof(me) - 1);
        printf("[+] Found myself: ‘%s‘\n", me);
        execve(*mee, mee, environ);

        for ( ep = environ; *ep != NULL; ep++)
                printf("environ: %s\n", *ep);

}