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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <AK/Vector.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/GetPassword.h>
#include <alloca.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
extern "C" int main(int, char**);
int main(int argc, char** argv)
{
const char* user = nullptr;
Core::ArgsParser args_parser;
args_parser.add_positional_argument(user, "User to switch to (defaults to user with UID 0)", "user", Core::ArgsParser::Required::No);
args_parser.parse(argc, argv);
if (geteuid() != 0)
fprintf(stderr, "Not running as root :(\n");
uid_t uid = 0;
gid_t gid = 0;
struct passwd* pwd = nullptr;
if (user) {
pwd = getpwnam(user);
if (!pwd) {
fprintf(stderr, "No such user: %s\n", user);
return 1;
}
uid = pwd->pw_uid;
gid = pwd->pw_gid;
}
if (!pwd)
pwd = getpwuid(0);
if (!pwd) {
fprintf(stderr, "No passwd entry.\n");
return 1;
}
if (getuid() != 0 && pwd->pw_passwd[0] != '\0') {
auto password = Core::get_password();
if (password.is_error()) {
fprintf(stderr, strerror(password.error()));
return 1;
}
char* hash = crypt(password.value().characters(), pwd->pw_passwd);
if (hash == NULL || strcmp(hash, pwd->pw_passwd) != 0) {
fprintf(stderr, "Incorrect or disabled password.\n");
return 1;
}
}
Vector<gid_t> extra_gids;
for (auto* group = getgrent(); group; group = getgrent()) {
for (size_t i = 0; group->gr_mem[i]; ++i) {
if (!strcmp(pwd->pw_name, group->gr_mem[i]))
extra_gids.append(group->gr_gid);
}
}
endgrent();
int rc = setgroups(extra_gids.size(), extra_gids.data());
if (rc < 0) {
perror("setgroups");
return 1;
}
rc = setgid(gid);
if (rc < 0) {
perror("setgid");
return 1;
}
rc = setuid(uid);
if (rc < 0) {
perror("setuid");
return 1;
}
rc = execl(pwd->pw_shell, pwd->pw_shell, nullptr);
perror("execl");
return 1;
}
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