From dc0f641956d002fa8588ef8d1213791cf36e92f2 Mon Sep 17 00:00:00 2001 From: Christian Poessinger Date: Tue, 20 Aug 2019 11:50:55 +0200 Subject: powerdns: T1524: support setting allow-from network Netmasks (both IPv4 and IPv6) that are allowed to use the server. The default allows access only from RFC 1918 private IP addresses. Due to the aggressive nature of the internet these days, it is highly recommended to not open up the recursor for the entire internet. Questions from IP addresses not listed here are ignored and do not get an answer. https://docs.powerdns.com/recursor/settings.html#allow-from Imagine an ISP network with non RFC1918 IP adresses - they can't make use of PowerDNS recursor. As of now VyOS hat allow-from set to 0.0.0.0/0 and ::/0 which created an open resolver. If there is no allow-from statement a config-migrator will add the appropriate nodes to the configuration, resulting in: service { dns { forwarding { allow-from 0.0.0.0/0 allow-from ::/0 cache-size 0 ignore-hosts-file listen-address 192.0.2.1 } } } --- src/conf_mode/dns_forwarding.py | 21 ++++++------ src/migration-scripts/dns-forwarding/0-to-1 | 50 +++++++++++++++++++++++++++++ 2 files changed, 62 insertions(+), 9 deletions(-) create mode 100755 src/migration-scripts/dns-forwarding/0-to-1 (limited to 'src') diff --git a/src/conf_mode/dns_forwarding.py b/src/conf_mode/dns_forwarding.py index 3ca77adee..86683e72c 100755 --- a/src/conf_mode/dns_forwarding.py +++ b/src/conf_mode/dns_forwarding.py @@ -44,7 +44,7 @@ config_tmpl = """ # Non-configurable defaults daemon=yes threads=1 -allow-from=0.0.0.0/0, ::/0 +allow-from={{ allow_from | join(',') }} log-common-errors=yes non-local-bind=yes query-local-address=0.0.0.0 @@ -83,6 +83,7 @@ dnssec={{ dnssec }} """ default_config_data = { + 'allow_from': [], 'cache_size': 10000, 'export_hosts_file': 'yes', 'listen_on': [], @@ -121,6 +122,9 @@ def get_config(arguments): conf.set_level('service dns forwarding') + if conf.exists('allow-from'): + dns['allow_from'] = conf.return_values('allow-from') + if conf.exists('cache-size'): cache_size = conf.return_value('cache-size') dns['cache_size'] = cache_size @@ -216,12 +220,10 @@ def get_config(arguments): return dns - def bracketize_ipv6_addrs(addrs): """Wraps each IPv6 addr in addrs in [], leaving IPv4 addrs untouched.""" return ['[{0}]'.format(a) if a.count(':') > 1 else a for a in addrs] - def verify(dns): # bail out early - looks like removal from running config if dns is None: @@ -231,6 +233,10 @@ def verify(dns): raise ConfigError( "Error: DNS forwarding requires either a listen-address (preferred) or a listen-on option") + if not dns['allow_from']: + raise ConfigError( + "Error: DNS forwarding requires an allow-from network") + if dns['domains']: for domain in dns['domains']: if not domain['servers']: @@ -239,7 +245,6 @@ def verify(dns): return None - def generate(dns): # bail out early - looks like removal from running config if dns is None: @@ -251,16 +256,14 @@ def generate(dns): f.write(config_text) return None - def apply(dns): - if dns is not None: - os.system("systemctl restart pdns-recursor") - else: + if dns is None: # DNS forwarding is removed in the commit os.system("systemctl stop pdns-recursor") if os.path.isfile(config_file): os.unlink(config_file) - + else: + os.system("systemctl restart pdns-recursor") if __name__ == '__main__': args = parser.parse_args() diff --git a/src/migration-scripts/dns-forwarding/0-to-1 b/src/migration-scripts/dns-forwarding/0-to-1 new file mode 100755 index 000000000..6e8720eef --- /dev/null +++ b/src/migration-scripts/dns-forwarding/0-to-1 @@ -0,0 +1,50 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2019 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 . +# + +# This migration script will check if there is a allow-from directive configured +# for the dns forwarding service - if not, the node will be created with the old +# default values of 0.0.0.0/0 and ::/0 + +import sys +from vyos.configtree import ConfigTree + +if (len(sys.argv) < 1): + print("Must specify file name!") + sys.exit(1) + +file_name = sys.argv[1] + +with open(file_name, 'r') as f: + config_file = f.read() + +config = ConfigTree(config_file) + +base = ['service', 'dns', 'forwarding'] +if not config.exists(base): + # Nothing to do + sys.exit(0) +else: + if not config.exists(base + ['allow-from']): + config.set(base + ['allow-from'], value='0.0.0.0/0', replace=False) + config.set(base + ['allow-from'], value='::/0', replace=False) + + try: + with open(file_name, 'w') as f: + f.write(config.to_string()) + except OSError as e: + print("Failed to save the modified config: {}".format(e)) + sys.exit(1) -- cgit v1.2.3