mirror of
https://github.com/RGBCube/serenity
synced 2025-05-14 09:14:58 +00:00
77e0598c6d
Before this patch, we had a nasty race condition when changing a user's password: there was a time window between truncating /etc/shadow and writing out its new contents, where you could simply "su" to root without using a password. Instead of writing directly to /etc/passwd and /etc/shadow, we now create temporary files in /etc and fill them with the new contents. Those files are then atomically renamed to /etc/passwd and /etc/shadow. Sadly, fixing this race requires giving the passwd program a lot more privileges. This is something we can and should improve upon. :^)
126 lines
4.2 KiB
C++
126 lines
4.2 KiB
C++
/*
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* Copyright (c) 2020, Peter Elliott <pelliott@ualberta.ca>
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* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/Types.h>
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#include <LibCore/Account.h>
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#include <LibCore/ArgsParser.h>
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#include <LibCore/File.h>
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#include <LibCore/GetPassword.h>
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#include <string.h>
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#include <unistd.h>
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int main(int argc, char** argv)
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{
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if (geteuid() != 0) {
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warnln("Not running as root :^(");
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return 1;
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}
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if (setegid(0) < 0) {
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perror("setegid");
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return 1;
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}
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if (pledge("stdio wpath rpath wpath cpath fattr tty", nullptr) < 0) {
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perror("pledge");
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return 1;
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}
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if (unveil("/etc", "rwc") < 0) {
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perror("unveil");
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return 1;
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}
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unveil(nullptr, nullptr);
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bool del = false;
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bool lock = false;
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bool unlock = false;
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const char* username = nullptr;
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auto args_parser = Core::ArgsParser();
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args_parser.set_general_help("Modify an account password.");
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args_parser.add_option(del, "Delete password", "delete", 'd');
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args_parser.add_option(lock, "Lock password", "lock", 'l');
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args_parser.add_option(unlock, "Unlock password", "unlock", 'u');
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args_parser.add_positional_argument(username, "Username", "username", Core::ArgsParser::Required::No);
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args_parser.parse(argc, argv);
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uid_t current_uid = getuid();
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auto account_or_error = (username)
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? Core::Account::from_name(username, Core::Account::OpenPasswdFile::ReadWrite, Core::Account::OpenShadowFile::ReadWrite)
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: Core::Account::from_uid(current_uid, Core::Account::OpenPasswdFile::ReadWrite, Core::Account::OpenShadowFile::ReadWrite);
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if (account_or_error.is_error()) {
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warnln("Core::Account::{}: {}", (username) ? "from_name" : "from_uid", account_or_error.error());
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return 1;
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}
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setpwent();
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if (pledge("stdio rpath wpath cpath fattr tty", nullptr) < 0) {
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perror("pledge");
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return 1;
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}
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// target_account is the account we are changing the password of.
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auto& target_account = account_or_error.value();
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if (current_uid != 0 && current_uid != target_account.uid()) {
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warnln("You can't modify passwd for {}", username);
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return 1;
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}
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if (del) {
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target_account.delete_password();
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} else if (lock) {
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target_account.set_password_enabled(false);
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} else if (unlock) {
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target_account.set_password_enabled(true);
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} else {
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auto new_password = Core::get_password("New password: ");
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if (new_password.is_error()) {
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warnln("{}", new_password.error());
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return 1;
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}
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target_account.set_password(new_password.value().characters());
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}
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if (pledge("stdio rpath wpath cpath fattr", nullptr) < 0) {
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perror("pledge");
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return 1;
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}
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if (!target_account.sync()) {
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perror("Core::Account::Sync");
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}
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return 0;
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}
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