yunohost/src/firewall.py
2021-11-10 17:56:02 +01:00

530 lines
17 KiB
Python

# -*- coding: utf-8 -*-
""" License
Copyright (C) 2013 YunoHost
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published
by the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
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 Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program; if not, see http://www.gnu.org/licenses
"""
""" yunohost_firewall.py
Manage firewall rules
"""
import os
import yaml
import miniupnpc
from moulinette import m18n
from yunohost.utils.error import YunohostError, YunohostValidationError
from moulinette.utils import process
from moulinette.utils.log import getActionLogger
FIREWALL_FILE = "/etc/yunohost/firewall.yml"
UPNP_CRON_JOB = "/etc/cron.d/yunohost-firewall-upnp"
logger = getActionLogger("yunohost.firewall")
def firewall_allow(
protocol, port, ipv4_only=False, ipv6_only=False, no_upnp=False, no_reload=False
):
"""
Allow connections on a port
Keyword arguments:
protocol -- Protocol type to allow (TCP/UDP/Both)
port -- Port or range of ports to open
ipv4_only -- Only add a rule for IPv4 connections
ipv6_only -- Only add a rule for IPv6 connections
no_upnp -- Do not add forwarding of this port with UPnP
no_reload -- Do not reload firewall rules
"""
firewall = firewall_list(raw=True)
# Validate port
if not isinstance(port, int) and ":" not in port:
port = int(port)
# Validate protocols
protocols = ["TCP", "UDP"]
if protocol != "Both" and protocol in protocols:
protocols = [
protocol,
]
# Validate IP versions
ipvs = ["ipv4", "ipv6"]
if ipv4_only and not ipv6_only:
ipvs = [
"ipv4",
]
elif ipv6_only and not ipv4_only:
ipvs = [
"ipv6",
]
for p in protocols:
# Iterate over IP versions to add port
for i in ipvs:
if port not in firewall[i][p]:
firewall[i][p].append(port)
else:
ipv = "IPv%s" % i[3]
logger.warning(m18n.n("port_already_opened", port=port, ip_version=ipv))
# Add port forwarding with UPnP
if not no_upnp and port not in firewall["uPnP"][p]:
firewall["uPnP"][p].append(port)
if (
p + "_TO_CLOSE" in firewall["uPnP"]
and port in firewall["uPnP"][p + "_TO_CLOSE"]
):
firewall["uPnP"][p + "_TO_CLOSE"].remove(port)
# Update and reload firewall
_update_firewall_file(firewall)
if not no_reload:
return firewall_reload()
def firewall_disallow(
protocol, port, ipv4_only=False, ipv6_only=False, upnp_only=False, no_reload=False
):
"""
Disallow connections on a port
Keyword arguments:
protocol -- Protocol type to disallow (TCP/UDP/Both)
port -- Port or range of ports to close
ipv4_only -- Only remove the rule for IPv4 connections
ipv6_only -- Only remove the rule for IPv6 connections
upnp_only -- Only remove forwarding of this port with UPnP
no_reload -- Do not reload firewall rules
"""
firewall = firewall_list(raw=True)
# Validate port
if not isinstance(port, int) and ":" not in port:
port = int(port)
# Validate protocols
protocols = ["TCP", "UDP"]
if protocol != "Both" and protocol in protocols:
protocols = [
protocol,
]
# Validate IP versions and UPnP
ipvs = ["ipv4", "ipv6"]
upnp = True
if ipv4_only and ipv6_only:
upnp = True # automatically disallow UPnP
elif ipv4_only:
ipvs = [
"ipv4",
]
upnp = upnp_only
elif ipv6_only:
ipvs = [
"ipv6",
]
upnp = upnp_only
elif upnp_only:
ipvs = []
for p in protocols:
# Iterate over IP versions to remove port
for i in ipvs:
if port in firewall[i][p]:
firewall[i][p].remove(port)
else:
ipv = "IPv%s" % i[3]
logger.warning(m18n.n("port_already_closed", port=port, ip_version=ipv))
# Remove port forwarding with UPnP
if upnp and port in firewall["uPnP"][p]:
firewall["uPnP"][p].remove(port)
if p + "_TO_CLOSE" not in firewall["uPnP"]:
firewall["uPnP"][p + "_TO_CLOSE"] = []
firewall["uPnP"][p + "_TO_CLOSE"].append(port)
# Update and reload firewall
_update_firewall_file(firewall)
if not no_reload:
return firewall_reload()
def firewall_list(raw=False, by_ip_version=False, list_forwarded=False):
"""
List all firewall rules
Keyword arguments:
raw -- Return the complete YAML dict
by_ip_version -- List rules by IP version
list_forwarded -- List forwarded ports with UPnP
"""
with open(FIREWALL_FILE) as f:
firewall = yaml.safe_load(f)
if raw:
return firewall
# Retrieve all ports for IPv4 and IPv6
ports = {}
for i in ["ipv4", "ipv6"]:
f = firewall[i]
# Combine TCP and UDP ports
ports[i] = sorted(
set(f["TCP"]) | set(f["UDP"]),
key=lambda p: int(p.split(":")[0]) if isinstance(p, str) else p,
)
if not by_ip_version:
# Combine IPv4 and IPv6 ports
ports = sorted(
set(ports["ipv4"]) | set(ports["ipv6"]),
key=lambda p: int(p.split(":")[0]) if isinstance(p, str) else p,
)
# Format returned dict
ret = {"opened_ports": ports}
if list_forwarded:
# Combine TCP and UDP forwarded ports
ret["forwarded_ports"] = sorted(
set(firewall["uPnP"]["TCP"]) | set(firewall["uPnP"]["UDP"]),
key=lambda p: int(p.split(":")[0]) if isinstance(p, str) else p,
)
return ret
def firewall_reload(skip_upnp=False):
"""
Reload all firewall rules
Keyword arguments:
skip_upnp -- Do not refresh port forwarding using UPnP
"""
from yunohost.hook import hook_callback
from yunohost.service import _run_service_command
reloaded = False
errors = False
# Check if SSH port is allowed
ssh_port = _get_ssh_port()
if ssh_port not in firewall_list()["opened_ports"]:
firewall_allow("TCP", ssh_port, no_reload=True)
# Retrieve firewall rules and UPnP status
firewall = firewall_list(raw=True)
upnp = firewall_upnp()["enabled"] if not skip_upnp else False
# IPv4
try:
process.check_output("iptables -w -L")
except process.CalledProcessError as e:
logger.debug(
"iptables seems to be not available, it outputs:\n%s",
e.output.decode().strip(),
)
logger.warning(m18n.n("iptables_unavailable"))
else:
rules = [
"iptables -w -F",
"iptables -w -X",
"iptables -w -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT",
]
# Iterate over ports and add rule
for protocol in ["TCP", "UDP"]:
for port in firewall["ipv4"][protocol]:
rules.append(
"iptables -w -A INPUT -p %s --dport %s -j ACCEPT"
% (protocol, process.quote(str(port)))
)
rules += [
"iptables -w -A INPUT -i lo -j ACCEPT",
"iptables -w -A INPUT -p icmp -j ACCEPT",
"iptables -w -P INPUT DROP",
]
# Execute each rule
if process.run_commands(rules, callback=_on_rule_command_error):
errors = True
reloaded = True
# IPv6
try:
process.check_output("ip6tables -L")
except process.CalledProcessError as e:
logger.debug(
"ip6tables seems to be not available, it outputs:\n%s",
e.output.decode().strip(),
)
logger.warning(m18n.n("ip6tables_unavailable"))
else:
rules = [
"ip6tables -w -F",
"ip6tables -w -X",
"ip6tables -w -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT",
]
# Iterate over ports and add rule
for protocol in ["TCP", "UDP"]:
for port in firewall["ipv6"][protocol]:
rules.append(
"ip6tables -w -A INPUT -p %s --dport %s -j ACCEPT"
% (protocol, process.quote(str(port)))
)
rules += [
"ip6tables -w -A INPUT -i lo -j ACCEPT",
"ip6tables -w -A INPUT -p icmpv6 -j ACCEPT",
"ip6tables -w -P INPUT DROP",
]
# Execute each rule
if process.run_commands(rules, callback=_on_rule_command_error):
errors = True
reloaded = True
if not reloaded:
raise YunohostError("firewall_reload_failed")
hook_callback(
"post_iptable_rules", args=[upnp, os.path.exists("/proc/net/if_inet6")]
)
if upnp:
# Refresh port forwarding with UPnP
firewall_upnp(no_refresh=False)
_run_service_command("reload", "fail2ban")
if errors:
logger.warning(m18n.n("firewall_rules_cmd_failed"))
else:
logger.success(m18n.n("firewall_reloaded"))
return firewall_list()
def firewall_upnp(action="status", no_refresh=False):
"""
Manage port forwarding using UPnP
Note: 'reload' action is deprecated and will be removed in the near
future. You should use 'status' instead - which retrieve UPnP status
and automatically refresh port forwarding if 'no_refresh' is False.
Keyword argument:
action -- Action to perform
no_refresh -- Do not refresh port forwarding
"""
firewall = firewall_list(raw=True)
enabled = firewall["uPnP"]["enabled"]
# Compatibility with previous version
if action == "reload":
logger.debug("'reload' action is deprecated and will be removed")
try:
# Remove old cron job
os.remove("/etc/cron.d/yunohost-firewall")
except Exception:
pass
action = "status"
no_refresh = False
if action == "status" and no_refresh:
# Only return current state
return {"enabled": enabled}
elif action == "enable" or (enabled and action == "status"):
# Add cron job
with open(UPNP_CRON_JOB, "w+") as f:
f.write(
"*/50 * * * * root "
"/usr/bin/yunohost firewall upnp status >>/dev/null\n"
)
# Open port 1900 to receive discovery message
if 1900 not in firewall["ipv4"]["UDP"]:
firewall_allow("UDP", 1900, no_upnp=True, no_reload=True)
if not enabled:
firewall_reload(skip_upnp=True)
enabled = True
elif action == "disable" or (not enabled and action == "status"):
try:
# Remove cron job
os.remove(UPNP_CRON_JOB)
except Exception:
pass
enabled = False
if action == "status":
no_refresh = True
else:
raise YunohostValidationError("action_invalid", action=action)
# Refresh port mapping using UPnP
if not no_refresh:
upnpc = miniupnpc.UPnP(localport=1)
upnpc.discoverdelay = 3000
# Discover UPnP device(s)
logger.debug("discovering UPnP devices...")
nb_dev = upnpc.discover()
logger.debug("found %d UPnP device(s)", int(nb_dev))
if nb_dev < 1:
logger.error(m18n.n("upnp_dev_not_found"))
enabled = False
else:
try:
# Select UPnP device
upnpc.selectigd()
except Exception:
logger.debug("unable to select UPnP device", exc_info=1)
enabled = False
else:
# Iterate over ports
for protocol in ["TCP", "UDP"]:
if protocol + "_TO_CLOSE" in firewall["uPnP"]:
for port in firewall["uPnP"][protocol + "_TO_CLOSE"]:
if not isinstance(port, int):
# FIXME : how should we handle port ranges ?
logger.warning("Can't use UPnP to close '%s'" % port)
continue
# Clean the mapping of this port
if upnpc.getspecificportmapping(port, protocol):
try:
upnpc.deleteportmapping(port, protocol)
except Exception:
pass
firewall["uPnP"][protocol + "_TO_CLOSE"] = []
for port in firewall["uPnP"][protocol]:
if not isinstance(port, int):
# FIXME : how should we handle port ranges ?
logger.warning("Can't use UPnP to open '%s'" % port)
continue
# Clean the mapping of this port
if upnpc.getspecificportmapping(port, protocol):
try:
upnpc.deleteportmapping(port, protocol)
except Exception:
pass
if not enabled:
continue
try:
# Add new port mapping
upnpc.addportmapping(
port,
protocol,
upnpc.lanaddr,
port,
"yunohost firewall: port %d" % port,
"",
)
except Exception:
logger.debug(
"unable to add port %d using UPnP", port, exc_info=1
)
enabled = False
_update_firewall_file(firewall)
if enabled != firewall["uPnP"]["enabled"]:
firewall = firewall_list(raw=True)
firewall["uPnP"]["enabled"] = enabled
_update_firewall_file(firewall)
if not no_refresh:
# Display success message if needed
if action == "enable" and enabled:
logger.success(m18n.n("upnp_enabled"))
elif action == "disable" and not enabled:
logger.success(m18n.n("upnp_disabled"))
# Make sure to disable UPnP
elif action != "disable" and not enabled:
firewall_upnp("disable", no_refresh=True)
if not enabled and (action == "enable" or 1900 in firewall["ipv4"]["UDP"]):
# Close unused port 1900
firewall_disallow("UDP", 1900, no_reload=True)
if not no_refresh:
firewall_reload(skip_upnp=True)
if action == "enable" and not enabled:
raise YunohostError("upnp_port_open_failed")
return {"enabled": enabled}
def firewall_stop():
"""
Stop iptables and ip6tables
"""
if os.system("iptables -w -P INPUT ACCEPT") != 0:
raise YunohostError("iptables_unavailable")
os.system("iptables -w -F")
os.system("iptables -w -X")
if os.path.exists("/proc/net/if_inet6"):
os.system("ip6tables -P INPUT ACCEPT")
os.system("ip6tables -F")
os.system("ip6tables -X")
if os.path.exists(UPNP_CRON_JOB):
firewall_upnp("disable")
def _get_ssh_port(default=22):
"""Return the SSH port to use
Retrieve the SSH port from the sshd_config file or used the default
one if it's not defined.
"""
from moulinette.utils.text import searchf
try:
m = searchf(r"^Port[ \t]+([0-9]+)$", "/etc/ssh/sshd_config", count=-1)
if m:
return int(m)
except Exception:
pass
return default
def _update_firewall_file(rules):
"""Make a backup and write new rules to firewall file"""
os.system("cp {0} {0}.old".format(FIREWALL_FILE))
with open(FIREWALL_FILE, "w") as f:
yaml.safe_dump(rules, f, default_flow_style=False)
def _on_rule_command_error(returncode, cmd, output):
"""Callback for rules commands error"""
# Log error and continue commands execution
logger.debug(
'"%s" returned non-zero exit status %d:\n%s',
cmd,
returncode,
output.decode().strip(),
)
return True