// -*- Mode: Go; indent-tabs-mode: t -*-

/*
 * Copyright (C) 2016 Canonical Ltd
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

package builtin

const timeserverControlSummary = `allows setting system time synchronization servers`

const timeserverControlBaseDeclarationSlots = `
  timeserver-control:
    allow-installation:
      slot-snap-type:
        - core
    deny-auto-connection: true
`

// http://bazaar.launchpad.net/~ubuntu-security/ubuntu-core-security/trunk/view/head:/data/apparmor/policygroups/ubuntu-core/16.04/timeserver-control
const timeserverControlConnectedPlugAppArmor = `
# Description: Can manage timeservers directly separate from config ubuntu-core.
# Can enable system clock NTP synchronization via timedated D-Bus interface,
# Can read all properties of /org/freedesktop/timedate1 D-Bus object; see
# https://www.freedesktop.org/wiki/Software/systemd/timedated/

#include <abstractions/dbus-strict>

# Won't work until LP: #1504657 is fixed. Requires reboot until timesyncd
# notices the change or systemd restarts it.
/etc/systemd/timesyncd.conf rw,

# Introspection of org.freedesktop.timedate1
# do not use peer=(label=unconfined) here since this is DBus activated
dbus (send)
    bus=system
    path=/org/freedesktop/timedate1
    interface=org.freedesktop.DBus.Introspectable
    member=Introspect,

dbus (send)
    bus=system
    path=/org/freedesktop/timedate1
    interface=org.freedesktop.timedate1
    member="SetNTP"
    peer=(label=unconfined),

# Read all properties from timedate1
# do not use peer=(label=unconfined) here since this is DBus activated
dbus (send)
    bus=system
    path=/org/freedesktop/timedate1
    interface=org.freedesktop.DBus.Properties
    member=Get{,All},

# Receive timedate1 property changed events
dbus (receive)
    bus=system
    path=/org/freedesktop/timedate1
    interface=org.freedesktop.DBus.Properties
    member=PropertiesChanged
    peer=(label=unconfined),

# As the core snap ships the timedatectl utility we can also allow
# clients to use it now that they have access to the relevant
# D-Bus method for controlling network time synchronization via
# timedatectl's set-ntp command.
/usr/bin/timedatectl{,.real} ixr,

# Silence this noisy denial. systemd utilities look at /proc/1/environ to see
# if running in a container, but they will fallback gracefully. No other
# interfaces allow this denial, so no problems with silencing it for now. Note
# that allowing this triggers a 'ptrace trace peer=unconfined' denial, which we
# want to avoid.
deny @{PROC}/1/environ r,
`

func init() {
	registerIface(&commonInterface{
		name:                  "timeserver-control",
		summary:               timeserverControlSummary,
		implicitOnCore:        true,
		implicitOnClassic:     true,
		baseDeclarationSlots:  timeserverControlBaseDeclarationSlots,
		connectedPlugAppArmor: timeserverControlConnectedPlugAppArmor,
	})
}
