Edit: /etc/apparmor.d/usr.sbin.chronyd (2838B)
# vim:syntax=apparmor
# Last Modified: Sun Sep 05 16:48:05 2021
abi
,
#include
/usr/sbin/chronyd flags=(attach_disconnected) {
#include
#include
# For /run/chrony to be created
capability chown,
# Give “root” the ability to read and write the PID file
capability dac_override,
capability dac_read_search,
# Needed to support HW timestamping
capability net_admin,
# Needed to allow NTP server sockets to be bound to a privileged port
capability net_bind_service,
# Needed to allow an NTP socket to be bound to a device using the
# SO_BINDTODEVICE socket option on kernels before 5.7
capability net_raw,
# Needed to drop privileges
capability setgid,
capability setuid,
# Needed to set the SCHED_FIFO real-time scheduler at the specified priority
# using the '-P' option
capability sys_nice,
# Needed to lock chronyd into RAM
capability sys_resource,
# Needed to set the system/real-time clock
capability sys_time,
/usr/sbin/chronyd mr,
/etc/chrony/{,**} r,
/var/lib/chrony/{,*} rw,
/var/log/chrony/{,*} rw,
@{run}/chrony/{,*} rw,
@{run}/chrony-dhcp/{,*} r,
# Using the “tempcomp” directive gives chronyd the ability to improve
# the stability and accuracy of the clock by compensating the temperature
# changes measured by a sensor close to the oscillator.
@{sys}/class/hwmon/hwmon[0-9]*/temp[0-9]*_input r,
@{sys}/devices/virtual/thermal/thermal_zone[0-9]*/hwmon[0-9]*/temp[0-9]*_input r,
# Support all paths suggested in the man page (LP: #1771028). Assume these
# are common use cases; others should be set as local include (see below).
# Configs using a 'chrony.' prefix like the tempcomp config file example
/etc/chrony.* r,
# Example gpsd socket is outside @{run}/chrony/
@{run}/chrony.*.sock rw,
# To sign replies to MS-SNTP clients by the smbd daemon
/var/lib/samba/ntp_signd/socket rw,
# Default path of the socket to sync with ptp4l
@{run}/refclock.ptp.sock rw,
# rtc
/etc/adjtime r,
/dev/rtc{,[0-9]*} rw,
# gps devices
/dev/pps[0-9]* rw,
/dev/ptp[0-9]* rw,
# Allow reading the chronyd configuration file that timemaster(8)
# generates, along with any other config files and sockets.
@{run}/timemaster/* r,
# Allow read-write access to the socket path(s).
@{run}/timemaster/chrony.SOCK[0-9]* rw,
# For use with clocks that report via shared memory (e.g. gpsd),
# you may need to give ntpd access to all of shared memory, though
# this can be considered dangerous. See https://launchpad.net/bugs/722815
# for details. To enable, add this to local/usr.sbin.chronyd:
# capability ipc_owner,
# Site-specific additions and overrides. See local/README for details.
#include
}