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firewall.py
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firewall.py
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#!/usr/bin/env python3
#
# Copyright (C) 2021-2022 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later 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/>.
import os
import re
from glob import glob
from json import loads
from sys import exit
from vyos.base import Warning
from vyos.config import Config
from vyos.configdict import node_changed
from vyos.configdiff import get_config_diff, Diff
from vyos.configdep import set_dependents, call_dependents
# from vyos.configverify import verify_interface_exists
from vyos.firewall import fqdn_config_parse
from vyos.firewall import geoip_update
from vyos.template import render
from vyos.utils.process import call
from vyos.utils.process import cmd
from vyos.utils.dict import dict_search_args
from vyos.utils.dict import dict_search_recursive
from vyos.utils.process import process_named_running
from vyos.utils.process import rc_cmd
from vyos import ConfigError
from vyos import airbag
airbag.enable()
nat_conf_script = 'nat.py'
policy_route_conf_script = 'policy-route.py'
nftables_conf = '/run/nftables.conf'
sysfs_config = {
'all_ping': {'sysfs': '/proc/sys/net/ipv4/icmp_echo_ignore_all', 'enable': '0', 'disable': '1'},
'broadcast_ping': {'sysfs': '/proc/sys/net/ipv4/icmp_echo_ignore_broadcasts', 'enable': '0', 'disable': '1'},
'ip_src_route': {'sysfs': '/proc/sys/net/ipv4/conf/*/accept_source_route'},
'ipv6_receive_redirects': {'sysfs': '/proc/sys/net/ipv6/conf/*/accept_redirects'},
'ipv6_src_route': {'sysfs': '/proc/sys/net/ipv6/conf/*/accept_source_route', 'enable': '0', 'disable': '-1'},
'log_martians': {'sysfs': '/proc/sys/net/ipv4/conf/all/log_martians'},
'receive_redirects': {'sysfs': '/proc/sys/net/ipv4/conf/*/accept_redirects'},
'send_redirects': {'sysfs': '/proc/sys/net/ipv4/conf/*/send_redirects'},
'source_validation': {'sysfs': '/proc/sys/net/ipv4/conf/*/rp_filter', 'disable': '0', 'strict': '1', 'loose': '2'},
'syn_cookies': {'sysfs': '/proc/sys/net/ipv4/tcp_syncookies'},
'twa_hazards_protection': {'sysfs': '/proc/sys/net/ipv4/tcp_rfc1337'}
}
valid_groups = [
'address_group',
'domain_group',
'network_group',
'port_group',
'interface_group'
]
nested_group_types = [
'address_group', 'network_group', 'mac_group',
'port_group', 'ipv6_address_group', 'ipv6_network_group'
]
snmp_change_type = {
'unknown': 0,
'add': 1,
'delete': 2,
'change': 3
}
snmp_event_source = 1
snmp_trap_mib = 'VYATTA-TRAP-MIB'
snmp_trap_name = 'mgmtEventTrap'
def geoip_updated(conf, firewall):
diff = get_config_diff(conf)
node_diff = diff.get_child_nodes_diff(['firewall'], expand_nodes=Diff.DELETE, recursive=True)
out = {
'name': [],
'ipv6_name': [],
'deleted_name': [],
'deleted_ipv6_name': []
}
updated = False
for key, path in dict_search_recursive(firewall, 'geoip'):
set_name = f'GEOIP_CC_{path[1]}_{path[2]}_{path[4]}'
if (path[0] == 'ipv4'):
out['name'].append(set_name)
elif (path[0] == 'ipv6'):
set_name = f'GEOIP_CC6_{path[1]}_{path[2]}_{path[4]}'
out['ipv6_name'].append(set_name)
updated = True
if 'delete' in node_diff:
for key, path in dict_search_recursive(node_diff['delete'], 'geoip'):
set_name = f'GEOIP_CC_{path[1]}_{path[2]}_{path[4]}'
if (path[0] == 'ipv4'):
out['deleted_name'].append(set_name)
elif (path[0] == 'ipv6'):
set_name = f'GEOIP_CC_{path[1]}_{path[2]}_{path[4]}'
out['deleted_ipv6_name'].append(set_name)
updated = True
if updated:
return out
return False
def get_config(config=None):
if config:
conf = config
else:
conf = Config()
base = ['firewall']
firewall = conf.get_config_dict(base, key_mangling=('-', '_'),
no_tag_node_value_mangle=True,
get_first_key=True,
with_recursive_defaults=True)
firewall['group_resync'] = bool('group' in firewall or node_changed(conf, base + ['group']))
if firewall['group_resync']:
# Update nat and policy-route as firewall groups were updated
set_dependents('group_resync', conf)
firewall['geoip_updated'] = geoip_updated(conf, firewall)
fqdn_config_parse(firewall)
return firewall
def verify_rule(firewall, rule_conf, ipv6):
if 'action' not in rule_conf:
raise ConfigError('Rule action must be defined')
if 'jump' in rule_conf['action'] and 'jump_target' not in rule_conf:
raise ConfigError('Action set to jump, but no jump-target specified')
if 'jump_target' in rule_conf:
if 'jump' not in rule_conf['action']:
raise ConfigError('jump-target defined, but action jump needed and it is not defined')
target = rule_conf['jump_target']
if not ipv6:
if target not in dict_search_args(firewall, 'ipv4', 'name'):
raise ConfigError(f'Invalid jump-target. Firewall name {target} does not exist on the system')
else:
if target not in dict_search_args(firewall, 'ipv6', 'name'):
raise ConfigError(f'Invalid jump-target. Firewall ipv6 name {target} does not exist on the system')
if 'queue_options' in rule_conf:
if 'queue' not in rule_conf['action']:
raise ConfigError('queue-options defined, but action queue needed and it is not defined')
if 'fanout' in rule_conf['queue_options'] and ('queue' not in rule_conf or '-' not in rule_conf['queue']):
raise ConfigError('queue-options fanout defined, then queue needs to be defined as a range')
if 'queue' in rule_conf and 'queue' not in rule_conf['action']:
raise ConfigError('queue defined, but action queue needed and it is not defined')
if 'fragment' in rule_conf:
if {'match_frag', 'match_non_frag'} <= set(rule_conf['fragment']):
raise ConfigError('Cannot specify both "match-frag" and "match-non-frag"')
if 'limit' in rule_conf:
if 'rate' in rule_conf['limit']:
rate_int = re.sub(r'\D', '', rule_conf['limit']['rate'])
if int(rate_int) < 1:
raise ConfigError('Limit rate integer cannot be less than 1')
if 'ipsec' in rule_conf:
if {'match_ipsec', 'match_non_ipsec'} <= set(rule_conf['ipsec']):
raise ConfigError('Cannot specify both "match-ipsec" and "match-non-ipsec"')
if 'recent' in rule_conf:
if not {'count', 'time'} <= set(rule_conf['recent']):
raise ConfigError('Recent "count" and "time" values must be defined')
tcp_flags = dict_search_args(rule_conf, 'tcp', 'flags')
if tcp_flags:
if dict_search_args(rule_conf, 'protocol') != 'tcp':
raise ConfigError('Protocol must be tcp when specifying tcp flags')
not_flags = dict_search_args(rule_conf, 'tcp', 'flags', 'not')
if not_flags:
duplicates = [flag for flag in tcp_flags if flag in not_flags]
if duplicates:
raise ConfigError(f'Cannot match a tcp flag as set and not set')
if 'protocol' in rule_conf:
if rule_conf['protocol'] == 'icmp' and ipv6:
raise ConfigError(f'Cannot match IPv4 ICMP protocol on IPv6, use ipv6-icmp')
if rule_conf['protocol'] == 'ipv6-icmp' and not ipv6:
raise ConfigError(f'Cannot match IPv6 ICMP protocol on IPv4, use icmp')
for side in ['destination', 'source']:
if side in rule_conf:
side_conf = rule_conf[side]
if len({'address', 'fqdn', 'geoip'} & set(side_conf)) > 1:
raise ConfigError('Only one of address, fqdn or geoip can be specified')
if 'group' in side_conf:
if len({'address_group', 'network_group', 'domain_group'} & set(side_conf['group'])) > 1:
raise ConfigError('Only one address-group, network-group or domain-group can be specified')
for group in valid_groups:
if group in side_conf['group']:
group_name = side_conf['group'][group]
fw_group = f'ipv6_{group}' if ipv6 and group in ['address_group', 'network_group'] else group
error_group = fw_group.replace("_", "-")
if group in ['address_group', 'network_group', 'domain_group']:
types = [t for t in ['address', 'fqdn', 'geoip'] if t in side_conf]
if types:
raise ConfigError(f'{error_group} and {types[0]} cannot both be defined')
if group_name and group_name[0] == '!':
group_name = group_name[1:]
group_obj = dict_search_args(firewall, 'group', fw_group, group_name)
if group_obj is None:
raise ConfigError(f'Invalid {error_group} "{group_name}" on firewall rule')
if not group_obj:
Warning(f'{error_group} "{group_name}" has no members!')
if 'port' in side_conf or dict_search_args(side_conf, 'group', 'port_group'):
if 'protocol' not in rule_conf:
raise ConfigError('Protocol must be defined if specifying a port or port-group')
if rule_conf['protocol'] not in ['tcp', 'udp', 'tcp_udp']:
raise ConfigError('Protocol must be tcp, udp, or tcp_udp when specifying a port or port-group')
if 'port' in side_conf and dict_search_args(side_conf, 'group', 'port_group'):
raise ConfigError(f'{side} port-group and port cannot both be defined')
if 'log_options' in rule_conf:
if 'log' not in rule_conf or 'enable' not in rule_conf['log']:
raise ConfigError('log-options defined, but log is not enable')
if 'snapshot_length' in rule_conf['log_options'] and 'group' not in rule_conf['log_options']:
raise ConfigError('log-options snapshot-length defined, but log group is not define')
if 'queue_threshold' in rule_conf['log_options'] and 'group' not in rule_conf['log_options']:
raise ConfigError('log-options queue-threshold defined, but log group is not define')
def verify_nested_group(group_name, group, groups, seen):
if 'include' not in group:
return
seen.append(group_name)
for g in group['include']:
if g not in groups:
raise ConfigError(f'Nested group "{g}" does not exist')
if g in seen:
raise ConfigError(f'Group "{group_name}" has a circular reference')
if 'include' in groups[g]:
verify_nested_group(g, groups[g], groups, seen)
def verify(firewall):
if 'group' in firewall:
for group_type in nested_group_types:
if group_type in firewall['group']:
groups = firewall['group'][group_type]
for group_name, group in groups.items():
verify_nested_group(group_name, group, groups, [])
if 'ipv4' in firewall:
for name in ['name','forward','input','output']:
if name in firewall['ipv4']:
for name_id, name_conf in firewall['ipv4'][name].items():
if 'jump' in name_conf['default_action'] and 'default_jump_target' not in name_conf:
raise ConfigError('default-action set to jump, but no default-jump-target specified')
if 'default_jump_target' in name_conf:
target = name_conf['default_jump_target']
if 'jump' not in name_conf['default_action']:
raise ConfigError('default-jump-target defined, but default-action jump needed and it is not defined')
if name_conf['default_jump_target'] == name_id:
raise ConfigError(f'Loop detected on default-jump-target.')
## Now need to check that default-jump-target exists (other firewall chain/name)
if target not in dict_search_args(firewall['ipv4'], 'name'):
raise ConfigError(f'Invalid jump-target. Firewall name {target} does not exist on the system')
if 'rule' in name_conf:
for rule_id, rule_conf in name_conf['rule'].items():
verify_rule(firewall, rule_conf, False)
if 'ipv6' in firewall:
for name in ['name','forward','input','output']:
if name in firewall['ipv6']:
for name_id, name_conf in firewall['ipv6'][name].items():
if 'jump' in name_conf['default_action'] and 'default_jump_target' not in name_conf:
raise ConfigError('default-action set to jump, but no default-jump-target specified')
if 'default_jump_target' in name_conf:
target = name_conf['default_jump_target']
if 'jump' not in name_conf['default_action']:
raise ConfigError('default-jump-target defined, but default-action jump needed and it is not defined')
if name_conf['default_jump_target'] == name_id:
raise ConfigError(f'Loop detected on default-jump-target.')
## Now need to check that default-jump-target exists (other firewall chain/name)
if target not in dict_search_args(firewall['ipv6'], 'name'):
raise ConfigError(f'Invalid jump-target. Firewall name {target} does not exist on the system')
if 'rule' in name_conf:
for rule_id, rule_conf in name_conf['rule'].items():
verify_rule(firewall, rule_conf, True)
return None
def generate(firewall):
if not os.path.exists(nftables_conf):
firewall['first_install'] = True
render(nftables_conf, 'firewall/nftables.j2', firewall)
return None
def apply_sysfs(firewall):
for name, conf in sysfs_config.items():
paths = glob(conf['sysfs'])
value = None
if name in firewall['global_options']:
conf_value = firewall['global_options'][name]
if conf_value in conf:
value = conf[conf_value]
elif conf_value == 'enable':
value = '1'
elif conf_value == 'disable':
value = '0'
if value:
for path in paths:
with open(path, 'w') as f:
f.write(value)
def post_apply_trap(firewall):
if 'first_install' in firewall:
return None
if not process_named_running('snmpd'):
return None
trap_username = os.getlogin()
for host, target_conf in firewall['trap_targets'].items():
community = target_conf['community'] if 'community' in target_conf else 'public'
port = int(target_conf['port']) if 'port' in target_conf else 162
base_cmd = f'snmptrap -v2c -c {community} {host}:{port} 0 {snmp_trap_mib}::{snmp_trap_name} '
for change_type, changes in firewall['trap_diff'].items():
for path_str, value in changes.items():
objects = [
f'mgmtEventUser s "{trap_username}"',
f'mgmtEventSource i {snmp_event_source}',
f'mgmtEventType i {snmp_change_type[change_type]}'
]
if change_type == 'add':
objects.append(f'mgmtEventCurrCfg s "{path_str} {value}"')
elif change_type == 'delete':
objects.append(f'mgmtEventPrevCfg s "{path_str} {value}"')
elif change_type == 'change':
objects.append(f'mgmtEventPrevCfg s "{path_str} {value[0]}"')
objects.append(f'mgmtEventCurrCfg s "{path_str} {value[1]}"')
cmd(base_cmd + ' '.join(objects))
def apply(firewall):
install_result, output = rc_cmd(f'nft -f {nftables_conf}')
if install_result == 1:
raise ConfigError(f'Failed to apply firewall: {output}')
apply_sysfs(firewall)
if firewall['group_resync']:
call_dependents()
# T970 Enable a resolver (systemd daemon) that checks
# domain-group/fqdn addresses and update entries for domains by timeout
# If router loaded without internet connection or for synchronization
domain_action = 'stop'
if dict_search_args(firewall, 'group', 'domain_group') or firewall['ip_fqdn'] or firewall['ip6_fqdn']:
domain_action = 'restart'
call(f'systemctl {domain_action} vyos-domain-resolver.service')
if firewall['geoip_updated']:
# Call helper script to Update set contents
if 'name' in firewall['geoip_updated'] or 'ipv6_name' in firewall['geoip_updated']:
print('Updating GeoIP. Please wait...')
geoip_update(firewall)
post_apply_trap(firewall)
return None
if __name__ == '__main__':
try:
c = get_config()
verify(c)
generate(c)
apply(c)
except ConfigError as e:
print(e)
exit(1)

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