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// SPDX-FileCopyrightText: 2025 Markus Uhlin <maxxe@rpblc.net>
// SPDX-License-Identifier: ISC
#include <sys/types.h>
#include <sys/stat.h>
#include <err.h>
#include <fcntl.h>
#include <pwd.h>
#include <string.h>
#include <unistd.h>
#include <filesystem>
#include <string>
#include "addgroup.h"
#include "prep_dir_for_privdrop.h"
#include "settings.h"
#include "utils.h"
namespace fs = std::filesystem;
static int
get_uid_and_gid(uid_t &uid, gid_t &gid)
{
struct passwd *pw = nullptr;
int i = 0;
if ((pw = getpwnam(settings_get("privdrop_user"))) == nullptr ||
!get_group_id(settings_get("sysgroup"), &i)) {
uid = 0;
gid = 0;
return -1;
}
uid = pw->pw_uid;
gid = static_cast<gid_t>(i);
return 0;
}
static int
check_prep_done(const char *p_path)
{
std::string path(p_path);
path.append("/").append(".prep_done");
if (file_exists(path.c_str()))
return 0;
return -1;
}
static void
prep_done(const char *p_path)
{
int fd;
std::string path(p_path);
uid_t uid = 0;
gid_t gid = 0;
path.append("/").append(".prep_done");
fd = open(path.c_str(), (O_RDWR|O_CREAT|O_TRUNC), (S_IRUSR|S_IWUSR|
S_IRGRP|S_IROTH));
if (fd < 0) {
warn("%s: open", __func__);
return;
}
dprintf(fd, "FICS dir preparation done.\n"
"Do not remove this file while FICS is installed.\n");
close(fd);
if (get_uid_and_gid(uid, gid) == 0) {
if (chown(path.c_str(), uid, gid) != 0)
warn("%s: chown", __func__);
}
}
int
drop_root_privileges(const char *path)
{
struct passwd *pw;
if ((pw = getpwnam(settings_get("privdrop_user"))) == nullptr) {
warnx("%s: password database search failed", __func__);
return -1;
} else if (chdir(path) != 0) {
warn("%s: chdir(%s)", __func__, path);
return -1;
} else if (setgid(pw->pw_gid) == -1) {
warn("%s: setgid", __func__);
return -1;
} else if (setegid(pw->pw_gid) == -1) {
warn("%s: setegid", __func__);
return -1;
} else if (setuid(pw->pw_uid) == -1) {
warn("%s: setuid", __func__);
return -1;
} else if (seteuid(pw->pw_uid) == -1) {
warn("%s: seteuid", __func__);
return -1;
}
return 0;
}
int
prep_dir_for_privdrop(const char *path)
{
if (path == nullptr || strcmp(path, "") == 0)
return -1;
else if (check_prep_done(path) == 0)
return 0;
try {
fs::path v_path = path;
fs::recursive_directory_iterator dir_it(v_path);
uid_t uid = 0;
gid_t gid = 0;
constexpr mode_t dir_mode = (S_IRWXU|S_IRGRP|S_IXGRP);
constexpr mode_t file_mode = (S_IRUSR|S_IWUSR|S_IRGRP);
if (get_uid_and_gid(uid, gid) == -1) {
throw std::runtime_error("failed to get uid/gid");
} else if (chown(path, uid, gid) != 0) {
std::string str("chown() error: ");
str.append(strerror(errno));
throw std::runtime_error(str);
} else if (chmod(path, dir_mode) != 0) {
std::string str("chmod() error: ");
str.append(strerror(errno));
throw std::runtime_error(str);
}
for (auto const &dir_ent : dir_it) {
const std::string str(dir_ent.path().string());
if (chown(str.c_str(), uid, gid) != 0) {
warn("%s: chown(%s, ...)", __func__,
str.c_str());
}
if (dir_ent.is_directory()) {
if (chmod(str.c_str(), dir_mode) != 0)
warn("%s: chmod", __func__);
} else if (dir_ent.is_regular_file()) {
if (chmod(str.c_str(), file_mode) != 0)
warn("%s: chmod", __func__);
}
}
} catch (const std::exception &ex) {
warnx("%s: %s", __func__, ex.what());
return -1;
}
prep_done(path);
return 0;
}
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