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/*
* Copyright (c) 2019-2020, Jesse Buhagiar <jooster669@gmail.com>
* Copyright (c) 2021, Brandon Pruitt <brapru@pm.me>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Base64.h>
#include <AK/Random.h>
#include <AK/String.h>
#include <LibCore/ArgsParser.h>
#include <crypt.h>
#include <ctype.h>
#include <errno.h>
#include <pwd.h>
#include <shadow.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
constexpr uid_t BASE_UID = 1000;
constexpr gid_t USERS_GID = 100;
constexpr const char* DEFAULT_SHELL = "/bin/sh";
int main(int argc, char** argv)
{
if (pledge("stdio wpath rpath cpath chown", nullptr) < 0) {
perror("pledge");
return 1;
}
const char* home_path = nullptr;
int uid = 0;
int gid = USERS_GID;
bool create_home_dir = false;
const char* password = "";
const char* shell = DEFAULT_SHELL;
const char* gecos = "";
const char* username = nullptr;
Core::ArgsParser args_parser;
args_parser.add_option(home_path, "Home directory for the new user", "home-dir", 'd', "path");
args_parser.add_option(uid, "User ID (uid) for the new user", "uid", 'u', "uid");
args_parser.add_option(gid, "Group ID (gid) for the new user", "gid", 'g', "gid");
args_parser.add_option(password, "Encrypted password of the new user", "password", 'p', "password");
args_parser.add_option(create_home_dir, "Create home directory if it does not exist", "create-home", 'm');
args_parser.add_option(shell, "Path to the default shell binary for the new user", "shell", 's', "path-to-shell");
args_parser.add_option(gecos, "GECOS name of the new user", "gecos", 'n', "general-info");
args_parser.add_positional_argument(username, "Login user identity (username)", "login");
args_parser.parse(argc, argv);
// Let's run a quick sanity check on username
if (strpbrk(username, "\\/!@#$%^&*()~+=`:\n")) {
warnln("invalid character in username, {}", username);
return 1;
}
// Disallow names starting with _ and -
if (username[0] == '_' || username[0] == '-' || !isalpha(username[0])) {
warnln("invalid username, {}", username);
return 1;
}
if (getpwnam(username)) {
warnln("user {} already exists!", username);
return 1;
}
if (uid < 0) {
warnln("invalid uid {}!", uid);
return 3;
}
// First, let's sort out the uid for the user
if (uid > 0) {
if (getpwuid(static_cast<uid_t>(uid))) {
warnln("uid {} already exists!", uid);
return 4;
}
} else {
for (uid = BASE_UID; getpwuid(static_cast<uid_t>(uid)); uid++) {
}
}
if (gid < 0) {
warnln("invalid gid {}", gid);
return 3;
}
FILE* pwfile = fopen("/etc/passwd", "a");
if (!pwfile) {
perror("failed to open /etc/passwd");
return 1;
}
FILE* spwdfile = fopen("/etc/shadow", "a");
if (!spwdfile) {
perror("failed to open /etc/shadow");
return 1;
}
String home;
if (!home_path)
home = String::formatted("/home/{}", username);
else
home = home_path;
if (create_home_dir) {
if (mkdir(home.characters(), 0700) < 0) {
auto saved_errno = errno;
warnln("Failed to create directory {}: {}", home, strerror(saved_errno));
return 12;
}
if (chown(home.characters(), static_cast<uid_t>(uid), static_cast<gid_t>(gid)) < 0) {
warnln("Failed to change owner of {} to {}:{}: {}", home, uid, gid, strerror(errno));
if (rmdir(home.characters()) < 0) {
warnln("Failed to remove directory {}: {}", home, strerror(errno));
return 12;
}
return 12;
}
}
auto get_salt = []() {
char random_data[12];
fill_with_random(random_data, sizeof(random_data));
StringBuilder builder;
builder.append("$5$");
builder.append(encode_base64(ReadonlyBytes(random_data, sizeof(random_data))));
return builder.build();
};
char* hash = crypt(password, get_salt().characters());
struct passwd p;
p.pw_name = const_cast<char*>(username);
p.pw_passwd = const_cast<char*>("!");
p.pw_dir = const_cast<char*>(home.characters());
p.pw_uid = static_cast<uid_t>(uid);
p.pw_gid = static_cast<gid_t>(gid);
p.pw_shell = const_cast<char*>(shell);
p.pw_gecos = const_cast<char*>(gecos);
struct spwd s;
s.sp_namp = const_cast<char*>(username);
s.sp_pwdp = const_cast<char*>(hash);
s.sp_lstchg = 18727;
s.sp_min = 0;
s.sp_max = 99999;
s.sp_warn = -1;
s.sp_inact = -1;
s.sp_expire = -1;
s.sp_flag = -1;
if (putpwent(&p, pwfile) < 0) {
perror("putpwent");
return 1;
}
if (putspent(&s, spwdfile) < 0) {
perror("putspent");
return 1;
}
fclose(pwfile);
fclose(spwdfile);
return 0;
}
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