# Authors: Martin Basti # # Copyright (C) 2007-2014 Red Hat # see file 'COPYING' for use and warranty information # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU 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 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 . # import logging import dns.name import dns.exception import dns.resolver import copy import six from ipapython.ipautil import UnsafeIPAddress if six.PY3: unicode = str logger = logging.getLogger(__name__) @six.python_2_unicode_compatible class DNSName(dns.name.Name): labels = None # make pylint happy @classmethod def from_text(cls, labels, origin=None): return cls(dns.name.from_text(labels, origin)) def __init__(self, labels, origin=None): try: if isinstance(labels, six.string_types): #pylint: disable=E1101 labels = dns.name.from_text(unicode(labels), origin).labels elif isinstance(labels, dns.name.Name): labels = labels.labels super(DNSName, self).__init__(labels) except UnicodeError as e: # dnspython bug, an invalid domain name returns the UnicodeError # instead of a dns.exception raise dns.exception.SyntaxError(e) def __bool__(self): #dns.name.from_text('@') is represented like empty tuple #we need to acting '@' as nonzero value return True __nonzero__ = __bool__ # for Python 2 def __copy__(self): return DNSName(self.labels) def __deepcopy__(self, memo): return DNSName(copy.deepcopy(self.labels, memo)) def __str__(self): return self.to_unicode() # method ToASCII named by RFC 3490 and python standard library if six.PY2: def ToASCII(self): # must be unicode string in Py2 return self.to_text().decode('ascii') else: def ToASCII(self): return self.to_text() def canonicalize(self): return DNSName(super(DNSName, self).canonicalize()) def concatenate(self, other): return DNSName(super(DNSName, self).concatenate(other)) def relativize(self, origin): return DNSName(super(DNSName, self).relativize(origin)) def derelativize(self, origin): return DNSName(super(DNSName, self).derelativize(origin)) def choose_relativity(self, origin=None, relativize=True): return DNSName(super(DNSName, self).choose_relativity(origin=origin, relativize=relativize)) def make_absolute(self): return self.derelativize(self.root) def is_idn(self): return any(label.startswith('xn--') for label in self.labels) def is_ip4_reverse(self): return self.is_subdomain(self.ip4_rev_zone) def is_ip6_reverse(self): return self.is_subdomain(self.ip6_rev_zone) def is_reverse(self): return self.is_ip4_reverse() or self.is_ip6_reverse() def is_empty(self): return len(self.labels) == 0 #DNS public constants DNSName.root = DNSName(dns.name.root) # '.' DNSName.empty = DNSName(dns.name.empty) # '@' DNSName.ip4_rev_zone = DNSName(('in-addr', 'arpa', '')) DNSName.ip6_rev_zone = DNSName(('ip6', 'arpa', '')) # Empty zones are defined in various RFCs. BIND is by default serving them. # This constat should contain everything listed in # IANA registry "Locally-Served DNS Zones" # URL: http://www.iana.org/assignments/locally-served-dns-zones # + AS112 zone defined in RFC 7534. It is not in the registry for some # reason but BIND 9.10 is serving it as automatic empty zones. EMPTY_ZONES = [DNSName(aez).make_absolute() for aez in [ # RFC 1918 "10.IN-ADDR.ARPA", "16.172.IN-ADDR.ARPA", "17.172.IN-ADDR.ARPA", "18.172.IN-ADDR.ARPA", "19.172.IN-ADDR.ARPA", "20.172.IN-ADDR.ARPA", "21.172.IN-ADDR.ARPA", "22.172.IN-ADDR.ARPA", "23.172.IN-ADDR.ARPA", "24.172.IN-ADDR.ARPA", "25.172.IN-ADDR.ARPA", "26.172.IN-ADDR.ARPA", "27.172.IN-ADDR.ARPA", "28.172.IN-ADDR.ARPA", "29.172.IN-ADDR.ARPA", "30.172.IN-ADDR.ARPA", "31.172.IN-ADDR.ARPA", "168.192.IN-ADDR.ARPA", # RFC 6598 "64.100.IN-ADDR.ARPA", "65.100.IN-ADDR.ARPA", "66.100.IN-ADDR.ARPA", "67.100.IN-ADDR.ARPA", "68.100.IN-ADDR.ARPA", "69.100.IN-ADDR.ARPA", "70.100.IN-ADDR.ARPA", "71.100.IN-ADDR.ARPA", "72.100.IN-ADDR.ARPA", "73.100.IN-ADDR.ARPA", "74.100.IN-ADDR.ARPA", "75.100.IN-ADDR.ARPA", "76.100.IN-ADDR.ARPA", "77.100.IN-ADDR.ARPA", "78.100.IN-ADDR.ARPA", "79.100.IN-ADDR.ARPA", "80.100.IN-ADDR.ARPA", "81.100.IN-ADDR.ARPA", "82.100.IN-ADDR.ARPA", "83.100.IN-ADDR.ARPA", "84.100.IN-ADDR.ARPA", "85.100.IN-ADDR.ARPA", "86.100.IN-ADDR.ARPA", "87.100.IN-ADDR.ARPA", "88.100.IN-ADDR.ARPA", "89.100.IN-ADDR.ARPA", "90.100.IN-ADDR.ARPA", "91.100.IN-ADDR.ARPA", "92.100.IN-ADDR.ARPA", "93.100.IN-ADDR.ARPA", "94.100.IN-ADDR.ARPA", "95.100.IN-ADDR.ARPA", "96.100.IN-ADDR.ARPA", "97.100.IN-ADDR.ARPA", "98.100.IN-ADDR.ARPA", "99.100.IN-ADDR.ARPA", "100.100.IN-ADDR.ARPA", "101.100.IN-ADDR.ARPA", "102.100.IN-ADDR.ARPA", "103.100.IN-ADDR.ARPA", "104.100.IN-ADDR.ARPA", "105.100.IN-ADDR.ARPA", "106.100.IN-ADDR.ARPA", "107.100.IN-ADDR.ARPA", "108.100.IN-ADDR.ARPA", "109.100.IN-ADDR.ARPA", "110.100.IN-ADDR.ARPA", "111.100.IN-ADDR.ARPA", "112.100.IN-ADDR.ARPA", "113.100.IN-ADDR.ARPA", "114.100.IN-ADDR.ARPA", "115.100.IN-ADDR.ARPA", "116.100.IN-ADDR.ARPA", "117.100.IN-ADDR.ARPA", "118.100.IN-ADDR.ARPA", "119.100.IN-ADDR.ARPA", "120.100.IN-ADDR.ARPA", "121.100.IN-ADDR.ARPA", "122.100.IN-ADDR.ARPA", "123.100.IN-ADDR.ARPA", "124.100.IN-ADDR.ARPA", "125.100.IN-ADDR.ARPA", "126.100.IN-ADDR.ARPA", "127.100.IN-ADDR.ARPA", # RFC 5735 and RFC 5737 "0.IN-ADDR.ARPA", "127.IN-ADDR.ARPA", "254.169.IN-ADDR.ARPA", "2.0.192.IN-ADDR.ARPA", "100.51.198.IN-ADDR.ARPA", "113.0.203.IN-ADDR.ARPA", "255.255.255.255.IN-ADDR.ARPA", # Local IPv6 Unicast Addresses "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.IP6.ARPA", "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.IP6.ARPA", # LOCALLY ASSIGNED LOCAL ADDRESS SCOPE "D.F.IP6.ARPA", "8.E.F.IP6.ARPA", "9.E.F.IP6.ARPA", "A.E.F.IP6.ARPA", "B.E.F.IP6.ARPA", # Example Prefix, RFC 3849. "8.B.D.0.1.0.0.2.IP6.ARPA", # RFC 7534 "EMPTY.AS112.ARPA", ]] def assert_absolute_dnsname(name): """Raise AssertionError if name is not DNSName or is not absolute. >>> assert_absolute_dnsname(DNSName('absolute.name.example.')) >>> assert_absolute_dnsname(DNSName('relative.name.example')) Traceback (most recent call last): ... AssertionError: name must be absolute, ... >>> assert_absolute_dnsname('absolute.string.example.') Traceback (most recent call last): ... AssertionError: name must be DNSName instance, ... """ assert isinstance(name, DNSName), ("name must be DNSName instance, " "got '%s'" % type(name)) assert name.is_absolute(), "name must be absolute, got '%s'" % name def is_auto_empty_zone(zone): """True if specified zone name exactly matches an automatic empty zone. >>> is_auto_empty_zone(DNSName('in-addr.arpa.')) False >>> is_auto_empty_zone(DNSName('10.in-addr.arpa.')) True >>> is_auto_empty_zone(DNSName('1.10.in-addr.arpa.')) False >>> is_auto_empty_zone(DNSName('10.in-addr.arpa')) Traceback (most recent call last): ... AssertionError: ... """ assert_absolute_dnsname(zone) return zone in EMPTY_ZONES def inside_auto_empty_zone(name): """True if specified absolute name is a subdomain of an automatic empty zone. DNS domain is a subdomain of itself so this function returns True for zone apexes, too. >>> inside_auto_empty_zone(DNSName('in-addr.arpa.')) False >>> inside_auto_empty_zone(DNSName('10.in-addr.arpa.')) True >>> inside_auto_empty_zone(DNSName('1.10.in-addr.arpa.')) True >>> inside_auto_empty_zone(DNSName('1.10.in-addr.arpa')) Traceback (most recent call last): ... AssertionError: ... """ assert_absolute_dnsname(name) for aez in EMPTY_ZONES: if name.is_subdomain(aez): return True return False def related_to_auto_empty_zone(name): """True if specified absolute name is a sub/superdomain of an automatic empty zone. DNS domain is a subdomain of itself so this function returns True for zone apexes, too. >>> related_to_auto_empty_zone(DNSName('.')) True >>> related_to_auto_empty_zone(DNSName('in-addr.arpa.')) True >>> related_to_auto_empty_zone(DNSName('10.in-addr.arpa.')) True >>> related_to_auto_empty_zone(DNSName('1.10.in-addr.arpa.')) True >>> related_to_auto_empty_zone(DNSName('unrelated.example.')) False >>> related_to_auto_empty_zone(DNSName('1.10.in-addr.arpa')) Traceback (most recent call last): ... AssertionError: ... """ assert_absolute_dnsname(name) relations = {dns.name.NAMERELN_SUBDOMAIN, dns.name.NAMERELN_EQUAL, dns.name.NAMERELN_SUPERDOMAIN} return any(name.fullcompare(aez)[0] in relations for aez in EMPTY_ZONES) def has_empty_zone_addresses(hostname): """Detect if given host is using IP address belonging to an automatic empty zone. Information from --ip-address option used in installed is lost by the time when upgrade is run. Use IP addresses from DNS as best approximation. This is brain-dead and duplicates logic from DNS installer but I did not find other way around. """ ip_addresses = resolve_ip_addresses(hostname) return any( inside_auto_empty_zone(DNSName(ip.reverse_dns)) for ip in ip_addresses ) def resolve_rrsets(fqdn, rdtypes): """ Get Resource Record sets for given FQDN. CNAME chain is followed during resolution but CNAMEs are not returned in the resulting rrset. :returns: set of dns.rrset.RRset objects, can be empty if the FQDN does not exist or if none of rrtypes exist """ # empty set of rdtypes would always return empty set of rrsets assert rdtypes, "rdtypes must not be empty" if not isinstance(fqdn, DNSName): fqdn = DNSName(fqdn) fqdn = fqdn.make_absolute() rrsets = [] for rdtype in rdtypes: try: answer = dns.resolver.query(fqdn, rdtype) logger.debug('found %d %s records for %s: %s', len(answer), rdtype, fqdn, ' '.join(str(rr) for rr in answer)) rrsets.append(answer.rrset) except dns.resolver.NXDOMAIN as ex: logger.debug('%s', ex) break # no such FQDN, do not iterate except dns.resolver.NoAnswer as ex: logger.debug('%s', ex) # record type does not exist for given FQDN except dns.exception.DNSException as ex: logger.error('DNS query for %s %s failed: %s', fqdn, rdtype, ex) raise return rrsets def resolve_ip_addresses(fqdn): """Get IP addresses from DNS A/AAAA records for given host (using DNS). :returns: list of IP addresses as UnsafeIPAddress objects """ rrsets = resolve_rrsets(fqdn, ['A', 'AAAA']) ip_addresses = set() for rrset in rrsets: ip_addresses.update({UnsafeIPAddress(ip) for ip in rrset}) return ip_addresses def check_zone_overlap(zone, raise_on_error=True): logger.info("Checking DNS domain %s, please wait ...", zone) if not isinstance(zone, DNSName): zone = DNSName(zone).make_absolute() # automatic empty zones always exist so checking them is pointless, # do not report them to avoid meaningless error messages if is_auto_empty_zone(zone): return try: containing_zone = dns.resolver.zone_for_name(zone) except dns.exception.DNSException as e: msg = ("DNS check for domain %s failed: %s." % (zone, e)) if raise_on_error: raise ValueError(msg) else: logger.warning('%s', msg) return if containing_zone == zone: try: ns = [ans.to_text() for ans in dns.resolver.query(zone, 'NS')] except dns.exception.DNSException as e: logger.debug("Failed to resolve nameserver(s) for domain %s: %s", zone, e) ns = [] msg = u"DNS zone {0} already exists in DNS".format(zone) if ns: msg += u" and is handled by server(s): {0}".format(', '.join(ns)) raise ValueError(msg)