diff --git a/docs/TRANSIENT-SETTINGS.md b/docs/TRANSIENT-SETTINGS.md
index 9f93e3b836..271d8ab1e3 100644
--- a/docs/TRANSIENT-SETTINGS.md
+++ b/docs/TRANSIENT-SETTINGS.md
@@ -192,6 +192,7 @@ All execution-related settings are available for transient units.
✓ PrivateUsers=
✓ ProtectSystem=
✓ ProtectHome=
+✓ ProtectClock=
✓ MountFlags=
✓ MountAPIVFS=
✓ Personality=
diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index c4cada2f27..b7f44c9473 100644
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -405,11 +405,11 @@ CapabilityBoundingSet=~CAP_B CAP_C
RestrictAddressFamilies=, RestrictNamespaces=,
PrivateDevices=, ProtectKernelTunables=,
ProtectKernelModules=, ProtectKernelLogs=,
- MemoryDenyWriteExecute=, RestrictRealtime=,
- RestrictSUIDSGID=, DynamicUser= or LockPersonality=
- are specified. Note that even if this setting is overridden by them, systemctl show shows the
- original value of this setting. Also see No New Privileges
+ ProtectClock=, MemoryDenyWriteExecute=,
+ RestrictRealtime=, RestrictSUIDSGID=, DynamicUser=
+ or LockPersonality= are specified. Note that even if this setting is overridden by them,
+ systemctl show shows the original value of this setting.
+ Also see No New Privileges
Flag.
@@ -1296,6 +1296,21 @@ BindReadOnlyPaths=/var/lib/systemd
+
+ ProtectClock=
+
+ Takes a boolean argument. If set, writes to the hardware clock or system clock will be denied.
+ It is recommended to turn this on for most services that do not need modify the clock. Defaults to off. Enabling
+ this option removes CAP_SYS_TIME and CAP_WAKE_ALARM from the
+ capability bounding set for this unit, installs a system call filter to block calls that can set the
+ clock, and DeviceAllow=char-rtc r is implied. This ensures /dev/rtc0,
+ /dev/rtc1, etc are made read only to the service. See
+ systemd.resource-control5
+ for the details about DeviceAllow=.
+
+
+
+
ProtectKernelTunables=
@@ -1807,7 +1822,7 @@ SystemCallErrorNumber=EPERM
mappings. Specifically these are the options PrivateTmp=,
PrivateDevices=, ProtectSystem=, ProtectHome=,
ProtectKernelTunables=, ProtectControlGroups=,
- ProtectKernelLogs=, ReadOnlyPaths=,
+ ProtectKernelLogs=, ProtectClock=, ReadOnlyPaths=,
InaccessiblePaths= and ReadWritePaths=.