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timesyncd: drop obsolete privilege dropping code

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systemd-timesyncd always runs as an unprivileged user via the service
file, so the code to resolve the systemd-timesync user, drop privileges
adjust file ownership/permissions, or even create the directory cannot
do anything useful and is unnecessary.

Follow-up for 00a415fc8f, which made
running under an unprivileged user unconditional.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2026-03-20 09:57:55 +01:00
committed by Zbigniew Jędrzejewski-Szmek
parent caed31e148
commit a28dbc9d88
1 changed files with 6 additions and 41 deletions
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src/timesync/timesyncd.c
+6 -41
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@@ -8,7 +8,6 @@
#include "bus-log-control-api.h"
#include "bus-object.h"
#include "capability-util.h"
#include "clock-util.h"
#include "daemon-util.h"
#include "errno-util.h"
@@ -17,14 +16,12 @@
#include "fs-util.h"
#include "log.h"
#include "main-func.h"
#include "mkdir-label.h"
#include "network-util.h"
#include "process-util.h"
#include "service-util.h"
#include "timesyncd-bus.h"
#include "timesyncd-conf.h"
#include "timesyncd-manager.h"
#include "user-util.h"
static int advance_tstamp(int fd, usec_t epoch) {
assert(fd >= 0);
@@ -72,7 +69,7 @@ static int advance_tstamp(int fd, usec_t epoch) {
return 0;
}
static int load_clock_timestamp(uid_t uid, gid_t gid) {
static int load_clock_timestamp(void) {
usec_t epoch = TIME_EPOCH * USEC_PER_SEC, ct;
_cleanup_close_ int fd = -EBADF;
int r;
@@ -82,18 +79,13 @@ static int load_clock_timestamp(uid_t uid, gid_t gid) {
* is particularly helpful on systems lacking a battery backed RTC. We also will adjust the time to
* at least the build time of systemd. */
fd = open(TIMESYNCD_CLOCK_FILE, O_RDWR|O_CLOEXEC, 0644);
fd = RET_NERRNO(open(TIMESYNCD_CLOCK_FILE, O_RDWR|O_CLOEXEC, 0644));
if (fd < 0) {
if (errno != ENOENT)
log_debug_errno(errno, "Unable to open timestamp file "TIMESYNCD_CLOCK_FILE", ignoring: %m");
r = mkdir_safe_label(TIMESYNCD_CLOCK_FILE_DIR, 0755, uid, gid,
MKDIR_FOLLOW_SYMLINK | MKDIR_WARN_MODE);
if (r < 0)
log_debug_errno(r, "Failed to create "TIMESYNCD_CLOCK_FILE_DIR", ignoring: %m");
if (fd != -ENOENT)
log_warning_errno(fd, "Unable to open timestamp file "TIMESYNCD_CLOCK_FILE", ignoring: %m");
/* Create stamp file with the compiled-in date */
r = touch_file(TIMESYNCD_CLOCK_FILE, /* parents= */ false, epoch, uid, gid, 0644);
r = touch_file(TIMESYNCD_CLOCK_FILE, /* parents= */ false, epoch, UID_INVALID, GID_INVALID, MODE_INVALID);
if (r < 0)
log_debug_errno(r, "Failed to create %s, ignoring: %m", TIMESYNCD_CLOCK_FILE);
} else {
@@ -103,13 +95,6 @@ static int load_clock_timestamp(uid_t uid, gid_t gid) {
if (fstat(fd, &st) < 0)
return log_error_errno(errno, "Unable to stat timestamp file "TIMESYNCD_CLOCK_FILE": %m");
/* Try to fix the access mode, so that we can still touch the file after dropping
* privileges */
r = fchmod_and_chown(fd, 0644, uid, gid);
if (r < 0)
log_full_errno(ERRNO_IS_PRIVILEGE(r) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to chmod or chown %s, ignoring: %m", TIMESYNCD_CLOCK_FILE);
epoch = MAX(epoch, timespec_load(&st.st_mtim));
(void) advance_tstamp(fd, epoch);
@@ -140,9 +125,6 @@ static int load_clock_timestamp(uid_t uid, gid_t gid) {
static int run(int argc, char *argv[]) {
_cleanup_(manager_freep) Manager *m = NULL;
_unused_ _cleanup_(notify_on_cleanup) const char *notify_message = NULL;
const char *user = "systemd-timesync";
uid_t uid, uid_current;
gid_t gid;
int r;
log_set_facility(LOG_CRON);
@@ -161,27 +143,10 @@ static int run(int argc, char *argv[]) {
if (argc != 1)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "This program does not take arguments.");
uid = uid_current = geteuid();
gid = getegid();
if (uid_current == 0) {
r = get_user_creds(&user, &uid, &gid, NULL, NULL, 0);
if (r < 0)
return log_error_errno(r, "Cannot resolve user name %s: %m", user);
}
r = load_clock_timestamp(uid, gid);
r = load_clock_timestamp();
if (r < 0)
return r;
/* Drop privileges, but only if we have been started as root. If we are not running as root we assume all
* privileges are already dropped. */
if (uid_current == 0) {
r = drop_privileges(uid, gid, (1ULL << CAP_SYS_TIME));
if (r < 0)
return log_error_errno(r, "Failed to drop privileges: %m");
}
r = manager_new(&m);
if (r < 0)
return log_error_errno(r, "Failed to allocate manager: %m");