fafff8f1ff
Let's fold get_user_creds_clean() into get_user_creds(), and introduce a flags argument for it to select "clean" behaviour. This flags parameter also learns to other new flags: - USER_CREDS_SYNTHESIZE_FALLBACK: in this mode the user records for root/nobody are only synthesized as fallback. Normally, the synthesized records take precedence over what is in the user database. With this flag set this is reversed, and the user database takes precedence, and the synthesized records are only used if they are missing there. This flag should be set in cases where doing NSS is deemed safe, and where there's interest in knowing the correct shell, for example if the admin changed root's shell to zsh or suchlike. - USER_CREDS_ALLOW_MISSING: if set, and a UID/GID is specified by numeric value, and there's no user/group record for it accept it anyway. This allows us to fix #9767 This then also ports all users to set the most appropriate flags. Fixes: #9767 [zj: remove one isempty() call]
192 lines
6.3 KiB
C
192 lines
6.3 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include "sd-daemon.h"
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#include "sd-event.h"
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#include "capability-util.h"
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#include "clock-util.h"
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#include "fd-util.h"
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#include "fs-util.h"
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#include "mkdir.h"
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#include "network-util.h"
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#include "process-util.h"
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#include "signal-util.h"
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#include "timesyncd-bus.h"
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#include "timesyncd-conf.h"
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#include "timesyncd-manager.h"
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#include "user-util.h"
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#define STATE_DIR "/var/lib/systemd/timesync"
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#define CLOCK_FILE STATE_DIR "/clock"
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static int load_clock_timestamp(uid_t uid, gid_t gid) {
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_cleanup_close_ int fd = -1;
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usec_t min = TIME_EPOCH * USEC_PER_SEC;
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usec_t ct;
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int r;
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/* Let's try to make sure that the clock is always
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* monotonically increasing, by saving the clock whenever we
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* have a new NTP time, or when we shut down, and restoring it
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* when we start again. This is particularly helpful on
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* systems lacking a battery backed RTC. We also will adjust
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* the time to at least the build time of systemd. */
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fd = open(CLOCK_FILE, O_RDWR|O_CLOEXEC, 0644);
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if (fd >= 0) {
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struct stat st;
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usec_t stamp;
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/* check if the recorded time is later than the compiled-in one */
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r = fstat(fd, &st);
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if (r >= 0) {
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stamp = timespec_load(&st.st_mtim);
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if (stamp > min)
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min = stamp;
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}
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if (geteuid() == 0) {
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/* Try to fix the access mode, so that we can still
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touch the file after dropping priviliges */
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r = fchmod_and_chown(fd, 0644, uid, gid);
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if (r < 0)
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log_warning_errno(r, "Failed to chmod or chown %s, ignoring: %m", CLOCK_FILE);
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}
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} else {
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r = mkdir_safe_label(STATE_DIR, 0755, uid, gid,
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MKDIR_FOLLOW_SYMLINK | MKDIR_WARN_MODE);
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if (r < 0) {
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log_debug_errno(r, "Failed to create state directory, ignoring: %m");
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goto settime;
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}
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/* create stamp file with the compiled-in date */
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r = touch_file(CLOCK_FILE, false, min, uid, gid, 0644);
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if (r < 0)
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log_debug_errno(r, "Failed to create %s, ignoring: %m", CLOCK_FILE);
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}
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settime:
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ct = now(CLOCK_REALTIME);
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if (ct < min) {
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struct timespec ts;
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char date[FORMAT_TIMESTAMP_MAX];
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log_info("System clock time unset or jumped backwards, restoring from recorded timestamp: %s",
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format_timestamp(date, sizeof(date), min));
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if (clock_settime(CLOCK_REALTIME, timespec_store(&ts, min)) < 0)
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log_error_errno(errno, "Failed to restore system clock, ignoring: %m");
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}
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return 0;
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}
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int main(int argc, char *argv[]) {
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_cleanup_(manager_freep) Manager *m = NULL;
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const char *user = "systemd-timesync";
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uid_t uid, uid_current;
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gid_t gid;
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int r;
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log_set_target(LOG_TARGET_AUTO);
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log_set_facility(LOG_CRON);
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log_parse_environment();
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log_open();
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umask(0022);
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if (argc != 1) {
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log_error("This program does not take arguments.");
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r = -EINVAL;
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goto finish;
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}
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uid = uid_current = geteuid();
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gid = getegid();
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if (uid_current == 0) {
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r = get_user_creds(&user, &uid, &gid, NULL, NULL, 0);
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if (r < 0) {
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log_error_errno(r, "Cannot resolve user name %s: %m", user);
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goto finish;
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}
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}
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r = load_clock_timestamp(uid, gid);
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if (r < 0)
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goto finish;
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/* Drop privileges, but only if we have been started as root. If we are not running as root we assume all
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* privileges are already dropped. */
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if (uid_current == 0) {
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r = drop_privileges(uid, gid, (1ULL << CAP_SYS_TIME));
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if (r < 0)
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goto finish;
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}
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assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGTERM, SIGINT, -1) >= 0);
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r = manager_new(&m);
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if (r < 0) {
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log_error_errno(r, "Failed to allocate manager: %m");
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goto finish;
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}
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r = manager_connect_bus(m);
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if (r < 0) {
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log_error_errno(r, "Could not connect to bus: %m");
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goto finish;
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}
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if (clock_is_localtime(NULL) > 0) {
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log_info("The system is configured to read the RTC time in the local time zone. "
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"This mode cannot be fully supported. All system time to RTC updates are disabled.");
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m->rtc_local_time = true;
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}
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r = manager_parse_config_file(m);
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if (r < 0)
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log_warning_errno(r, "Failed to parse configuration file: %m");
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r = manager_parse_fallback_string(m, NTP_SERVERS);
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if (r < 0) {
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log_error_errno(r, "Failed to parse fallback server strings: %m");
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goto finish;
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}
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log_debug("systemd-timesyncd running as pid " PID_FMT, getpid_cached());
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sd_notify(false,
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"READY=1\n"
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"STATUS=Daemon is running");
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if (network_is_online()) {
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r = manager_connect(m);
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if (r < 0)
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goto finish;
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}
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r = sd_event_loop(m->event);
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if (r < 0) {
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log_error_errno(r, "Failed to run event loop: %m");
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goto finish;
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}
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/* if we got an authoritative time, store it in the file system */
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if (m->sync) {
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r = touch(CLOCK_FILE);
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if (r < 0)
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log_debug_errno(r, "Failed to touch %s, ignoring: %m", CLOCK_FILE);
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}
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sd_event_get_exit_code(m->event, &r);
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finish:
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sd_notify(false,
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"STOPPING=1\n"
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"STATUS=Shutting down...");
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return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
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}
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