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freeipa/ipaserver/install/bindinstance.py
Cédric Jeanneret 6c27104467 Prevents DNS Amplification Attack and allow to customize named 
While [1] did open recursion, it also opened widely a security flaw.

This patch intends to close it back, while allowing operators to easily
add their open configuration within Bind9.

In order to allow operators to still open Bind recursion, a new file is
introduced, "ipa-ext.conf" (path might change according to the OS). This
file is not managed by the installer, meaning changes to it won't be
overridden.
Since it's included at the very end of the main configuration file, it
also allows to override some defaults - of course, operators have to be
careful with that.

Related-Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1754530
Fixes: https://pagure.io/freeipa/issue/8079

[1] 5f4c75eb28

Reviewed-By: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Stanislav Levin <slev@altlinux.org>
2019-11-12 10:49:49 +02:00

1267 lines
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# Authors: Simo Sorce <ssorce@redhat.com>
#
# Copyright (C) 2007 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 <http://www.gnu.org/licenses/>.
#
from __future__ import absolute_import
from __future__ import print_function
import logging
import tempfile
import os
import pwd
import netaddr
import re
import sys
import time
import dns.resolver
import ldap
import six
from ipaserver.dns_data_management import (
IPASystemRecords,
IPADomainIsNotManagedByIPAError,
)
from ipaserver.install import installutils
from ipaserver.install import service
from ipaserver.install import sysupgrade
from ipaserver.masters import get_masters
from ipapython import ipaldap
from ipapython import ipautil
from ipapython import dnsutil
from ipapython.dnsutil import DNSName
from ipapython.dn import DN
from ipapython.admintool import ScriptError
import ipalib
from ipalib import api, errors
from ipalib.constants import IPA_CA_RECORD
from ipaplatform import services
from ipaplatform.tasks import tasks
from ipaplatform.constants import constants
from ipaplatform.paths import paths
from ipalib.util import (validate_zonemgr_str, normalize_zonemgr,
get_dns_forward_zone_update_policy,
get_dns_reverse_zone_update_policy,
normalize_zone, get_reverse_zone_default,
zone_is_reverse, validate_dnssec_global_forwarder,
DNSSECSignatureMissingError, EDNS0UnsupportedError,
UnresolvableRecordError)
if six.PY3:
unicode = str
logger = logging.getLogger(__name__)
named_conf_section_ipa_start_re = re.compile(r'\s*dyndb\s+"ipa"\s+"[^"]+"\s+{')
named_conf_section_options_start_re = re.compile(r'\s*options\s+{')
named_conf_section_end_re = re.compile('};')
named_conf_arg_ipa_re = re.compile(
r'(?P<indent>\s*)(?P<name>\S+)\s"(?P<value>[^"]+)";')
named_conf_arg_options_re = re.compile(
r'(?P<indent>\s*)(?P<name>\S+)\s+"(?P<value>[^"]+)"\s*;')
named_conf_arg_ipa_template = "%(indent)s%(name)s \"%(value)s\";\n"
named_conf_arg_options_template = "%(indent)s%(name)s \"%(value)s\";\n"
# non string args for options section
named_conf_arg_options_re_nonstr = re.compile(
r'(?P<indent>\s*)(?P<name>\S+)\s+(?P<value>[^"]+)\s*;')
named_conf_arg_options_template_nonstr = "%(indent)s%(name)s %(value)s;\n"
# include directive
named_conf_include_re = re.compile(r'\s*include\s+"(?P<path>)"\s*;')
named_conf_include_template = "include \"%(path)s\";\n"
NAMED_SECTION_OPTIONS = "options"
NAMED_SECTION_IPA = "ipa"
def create_reverse():
return ipautil.user_input(
"Do you want to search for missing reverse zones?",
True
)
def named_conf_exists():
"""
Checks that named.conf exists AND that it contains IPA-related config.
"""
try:
with open(paths.NAMED_CONF, 'r') as named_fd:
lines = named_fd.readlines()
except IOError:
return False
for line in lines:
if named_conf_section_ipa_start_re.match(line):
return True
return False
def named_conf_get_directive(name, section=NAMED_SECTION_IPA, str_val=True):
"""Get a configuration option in bind-dyndb-ldap section of named.conf
:str_val - set to True if directive value is string
(only for NAMED_SECTION_OPTIONS)
"""
if section == NAMED_SECTION_IPA:
named_conf_section_start_re = named_conf_section_ipa_start_re
named_conf_arg_re = named_conf_arg_ipa_re
elif section == NAMED_SECTION_OPTIONS:
named_conf_section_start_re = named_conf_section_options_start_re
if str_val:
named_conf_arg_re = named_conf_arg_options_re
else:
named_conf_arg_re = named_conf_arg_options_re_nonstr
else:
raise NotImplementedError('Section "%s" is not supported' % section)
with open(paths.NAMED_CONF, 'r') as f:
target_section = False
for line in f:
if named_conf_section_start_re.match(line):
target_section = True
continue
if named_conf_section_end_re.match(line):
if target_section:
break
if target_section:
match = named_conf_arg_re.match(line)
if match and name == match.group('name'):
return match.group('value')
return None
def named_conf_set_directive(name, value, section=NAMED_SECTION_IPA,
str_val=True):
"""
Set configuration option in bind-dyndb-ldap section of named.conf.
When the configuration option with given name does not exist, it
is added at the end of ipa section in named.conf.
If the value is set to None, the configuration option is removed
from named.conf.
:str_val - set to True if directive value is string
(only for NAMED_SECTION_OPTIONS)
"""
new_lines = []
if section == NAMED_SECTION_IPA:
named_conf_section_start_re = named_conf_section_ipa_start_re
named_conf_arg_re = named_conf_arg_ipa_re
named_conf_arg_template = named_conf_arg_ipa_template
elif section == NAMED_SECTION_OPTIONS:
named_conf_section_start_re = named_conf_section_options_start_re
if str_val:
named_conf_arg_re = named_conf_arg_options_re
named_conf_arg_template = named_conf_arg_options_template
else:
named_conf_arg_re = named_conf_arg_options_re_nonstr
named_conf_arg_template = named_conf_arg_options_template_nonstr
else:
raise NotImplementedError('Section "%s" is not supported' % section)
with open(paths.NAMED_CONF, 'r') as f:
target_section = False
matched = False
last_indent = "\t"
for line in f:
if named_conf_section_start_re.match(line):
target_section = True
if named_conf_section_end_re.match(line):
if target_section and not matched and \
value is not None:
# create a new conf
new_conf = named_conf_arg_template \
% dict(indent=last_indent,
name=name,
value=value)
new_lines.append(new_conf)
target_section = False
if target_section and not matched:
match = named_conf_arg_re.match(line)
if match:
last_indent = match.group('indent')
if name == match.group('name'):
matched = True
if value is not None:
if not isinstance(value, str):
value = str(value)
new_conf = named_conf_arg_template \
% dict(indent=last_indent,
name=name,
value=value)
new_lines.append(new_conf)
continue
new_lines.append(line)
# write new configuration
with open(paths.NAMED_CONF, 'w') as f:
f.write("".join(new_lines))
def named_conf_include_exists(path):
"""
Check if include exists in named.conf
:param path: path in include directive
:return: True if include exists, else False
"""
with open(paths.NAMED_CONF, 'r') as f:
for line in f:
match = named_conf_include_re.match(line)
if match and path == match.group('path'):
return True
return False
def named_conf_add_include(path):
"""
append include at the end of file
:param path: path to be insert to include directive
"""
with open(paths.NAMED_CONF, 'a') as f:
f.write(named_conf_include_template % {'path': path})
def dns_container_exists(suffix):
"""
Test whether the dns container exists.
"""
assert isinstance(suffix, DN)
return api.Backend.ldap2.entry_exists(DN(('cn', 'dns'), suffix))
def dns_zone_exists(name, api=api):
try:
zone = api.Command.dnszone_show(unicode(name))
except ipalib.errors.NotFound:
return False
if len(zone) == 0:
return False
else:
return True
def get_reverse_record_name(zone, ip_address):
ip = netaddr.IPAddress(ip_address)
rev = '.' + normalize_zone(zone)
fullrev = '.' + normalize_zone(ip.reverse_dns)
if not fullrev.endswith(rev):
raise ValueError("IP address does not match reverse zone")
return fullrev[1:-len(rev)]
def verify_reverse_zone(zone, ip_address):
try:
get_reverse_record_name(zone, ip_address)
except ValueError:
return False
return True
def find_reverse_zone(ip_address, api=api):
ip = netaddr.IPAddress(ip_address)
zone = normalize_zone(ip.reverse_dns)
while len(zone) > 0:
if dns_zone_exists(zone, api):
return zone
zone = zone.partition('.')[2]
return None
def named_add_ext_conf_file(src, dest, t_params={}):
"""
Ensure included file is present, but don't override it.
:param src: String. Absolute path to source template
:param dest: String. Absolute path to destination
:param t_params: Dict. Parameters for source template
"""
if not os.path.exists(dest):
ipa_ext_txt = ipautil.template_file(src, t_params)
gid = pwd.getpwnam(constants.NAMED_USER).pw_gid
with open(dest, 'w') as ipa_ext:
os.fchmod(ipa_ext.fileno(), 0o640)
os.fchown(ipa_ext.fileno(), 0, gid)
ipa_ext.write(ipa_ext_txt)
return True
return False
def read_reverse_zone(default, ip_address, allow_zone_overlap=False):
while True:
zone = ipautil.user_input("Please specify the reverse zone name", default=default)
if not zone:
return None
if not verify_reverse_zone(zone, ip_address):
logger.error("Invalid reverse zone %s for IP address %s",
zone, ip_address)
continue
if not allow_zone_overlap:
try:
dnsutil.check_zone_overlap(zone, raise_on_error=False)
except ValueError as e:
logger.error("Reverse zone %s will not be used: %s",
zone, e)
continue
break
return normalize_zone(zone)
def get_auto_reverse_zones(ip_addresses, allow_zone_overlap=False):
auto_zones = []
for ip in ip_addresses:
if ipautil.reverse_record_exists(ip):
# PTR exist there is no reason to create reverse zone
logger.info("Reverse record for IP address %s already exists", ip)
continue
default_reverse = get_reverse_zone_default(ip)
if not allow_zone_overlap:
try:
dnsutil.check_zone_overlap(default_reverse)
except ValueError as e:
logger.info("Reverse zone %s for IP address %s already exists",
default_reverse, ip)
logger.debug('%s', e)
continue
auto_zones.append((ip, default_reverse))
return auto_zones
def add_zone(name, zonemgr=None, dns_backup=None, ns_hostname=None,
update_policy=None, force=False, skip_overlap_check=False,
api=api):
# always normalize zones
name = normalize_zone(name)
if update_policy is None:
if zone_is_reverse(name):
update_policy = get_dns_reverse_zone_update_policy(api.env.realm, name)
else:
update_policy = get_dns_forward_zone_update_policy(api.env.realm)
if zonemgr is None:
zonemgr = 'hostmaster.%s' % name
if ns_hostname:
ns_hostname = normalize_zone(ns_hostname)
ns_hostname = unicode(ns_hostname)
try:
api.Command.dnszone_add(unicode(name),
idnssoamname=ns_hostname,
idnssoarname=unicode(zonemgr),
idnsallowdynupdate=True,
idnsupdatepolicy=unicode(update_policy),
idnsallowquery=u'any',
idnsallowtransfer=u'none',
skip_overlap_check=skip_overlap_check,
force=force)
except (errors.DuplicateEntry, errors.EmptyModlist):
pass
def add_rr(zone, name, type, rdata, dns_backup=None, api=api, **kwargs):
addkw = {'%srecord' % str(type.lower()): unicode(rdata)}
addkw.update(kwargs)
try:
api.Command.dnsrecord_add(unicode(zone), unicode(name), **addkw)
except (errors.DuplicateEntry, errors.EmptyModlist):
pass
if dns_backup:
dns_backup.add(zone, type, name, rdata)
def add_fwd_rr(zone, host, ip_address, api=api):
addr = netaddr.IPAddress(ip_address)
if addr.version == 4:
add_rr(zone, host, "A", ip_address, None, api)
elif addr.version == 6:
add_rr(zone, host, "AAAA", ip_address, None, api)
def add_ptr_rr(zone, ip_address, fqdn, dns_backup=None, api=api):
name = get_reverse_record_name(zone, ip_address)
add_rr(zone, name, "PTR", normalize_zone(fqdn), dns_backup, api)
def add_ns_rr(zone, hostname, dns_backup=None, force=True, api=api):
hostname = normalize_zone(hostname)
add_rr(zone, "@", "NS", hostname, dns_backup=dns_backup,
force=force, api=api)
def del_rr(zone, name, type, rdata, api=api):
delkw = { '%srecord' % str(type.lower()) : unicode(rdata) }
try:
api.Command.dnsrecord_del(unicode(zone), unicode(name), **delkw)
except (errors.NotFound, errors.AttrValueNotFound, errors.EmptyModlist):
pass
def del_fwd_rr(zone, host, ip_address, api=api):
addr = netaddr.IPAddress(ip_address)
if addr.version == 4:
del_rr(zone, host, "A", ip_address, api=api)
elif addr.version == 6:
del_rr(zone, host, "AAAA", ip_address, api=api)
def del_ns_rr(zone, name, rdata, api=api):
del_rr(zone, name, 'NS', rdata, api=api)
def get_rr(zone, name, type, api=api):
rectype = '%srecord' % unicode(type.lower())
ret = api.Command.dnsrecord_find(unicode(zone), unicode(name))
if ret['count'] > 0:
for r in ret['result']:
if rectype in r:
return r[rectype]
return []
def get_fwd_rr(zone, host, api=api):
return [x for t in ("A", "AAAA") for x in get_rr(zone, host, t, api)]
def zonemgr_callback(option, opt_str, value, parser):
"""
Properly validate and convert --zonemgr Option to IA5String
"""
if value is not None:
# validate the value first
if six.PY3:
try:
validate_zonemgr_str(value)
except ValueError as e:
parser.error("invalid zonemgr: {}".format(e))
else:
try:
# IDNA support requires unicode
encoding = getattr(sys.stdin, 'encoding', None)
if encoding is None:
encoding = 'utf-8'
# value is of a string type in both py2 and py3
if not isinstance(value, unicode):
value = value.decode(encoding)
validate_zonemgr_str(value)
except ValueError as e:
# FIXME we can do this in better way
# https://fedorahosted.org/freeipa/ticket/4804
# decode to proper stderr encoding
stderr_encoding = getattr(sys.stderr, 'encoding', None)
if stderr_encoding is None:
stderr_encoding = 'utf-8'
error = unicode(e).encode(stderr_encoding)
parser.error(b"invalid zonemgr: " + error)
parser.values.zonemgr = value
def check_reverse_zones(ip_addresses, reverse_zones, options, unattended,
search_reverse_zones=False):
checked_reverse_zones = []
if (not options.no_reverse and not reverse_zones
and not options.auto_reverse):
if unattended:
options.no_reverse = True
else:
options.no_reverse = not create_reverse()
# shortcut
if options.no_reverse:
return []
# verify zones passed in options
for rz in reverse_zones:
# isn't the zone managed by someone else
if not options.allow_zone_overlap:
try:
dnsutil.check_zone_overlap(rz)
except ValueError as e:
msg = "Reverse zone %s will not be used: %s" % (rz, e)
if unattended:
raise ScriptError(msg)
else:
logger.warning('%s', msg)
continue
checked_reverse_zones.append(normalize_zone(rz))
# check that there is reverse zone for every IP
ips_missing_reverse = []
for ip in ip_addresses:
if search_reverse_zones and find_reverse_zone(str(ip)):
# reverse zone is already in LDAP
continue
for rz in checked_reverse_zones:
if verify_reverse_zone(rz, ip):
# reverse zone was entered by user
break
else:
ips_missing_reverse.append(ip)
# create reverse zone for IP addresses that does not have one
for (ip, rz) in get_auto_reverse_zones(ips_missing_reverse,
options.allow_zone_overlap):
if options.auto_reverse:
logger.info("Reverse zone %s will be created", rz)
checked_reverse_zones.append(rz)
elif unattended:
logger.warning("Missing reverse record for IP address %s", ip)
else:
if ipautil.user_input("Do you want to create reverse zone for IP "
"%s" % ip, True):
rz = read_reverse_zone(rz, str(ip), options.allow_zone_overlap)
checked_reverse_zones.append(rz)
return checked_reverse_zones
def check_forwarders(dns_forwarders):
print("Checking DNS forwarders, please wait ...")
forwarders_dnssec_valid = True
for forwarder in dns_forwarders:
logger.debug("Checking DNS server: %s", forwarder)
try:
validate_dnssec_global_forwarder(forwarder)
except DNSSECSignatureMissingError as e:
forwarders_dnssec_valid = False
logger.warning("DNS server %s does not support DNSSEC: %s",
forwarder, e)
logger.warning("Please fix forwarder configuration to enable "
"DNSSEC support.\n"
"(For BIND 9 add directive \"dnssec-enable yes;\" "
"to \"options {}\")")
print("DNS server %s: %s" % (forwarder, e))
print("Please fix forwarder configuration to enable DNSSEC support.")
print("(For BIND 9 add directive \"dnssec-enable yes;\" to \"options {}\")")
except EDNS0UnsupportedError as e:
forwarders_dnssec_valid = False
logger.warning("DNS server %s does not support ENDS0 "
"(RFC 6891): %s", forwarder, e)
logger.warning("Please fix forwarder configuration. "
"DNSSEC support cannot be enabled without EDNS0")
print(("WARNING: DNS server %s does not support EDNS0 "
"(RFC 6891): %s" % (forwarder, e)))
except UnresolvableRecordError as e:
logger.error("DNS server %s: %s", forwarder, e)
raise RuntimeError("DNS server %s: %s" % (forwarder, e))
return forwarders_dnssec_valid
def remove_master_dns_records(hostname, realm):
bind = BindInstance()
bind.remove_master_dns_records(hostname, realm, realm.lower())
bind.remove_server_ns_records(hostname)
def ensure_dnsserver_container_exists(ldap, api_instance, logger=logger):
"""
Create cn=servers,cn=dns,$SUFFIX container. If logger is not None, emit a
message that the container already exists when DuplicateEntry is raised
"""
entry = ldap.make_entry(
DN(api_instance.env.container_dnsservers, api_instance.env.basedn),
{
u'objectclass': [u'top', u'nsContainer'],
u'cn': [u'servers']
}
)
try:
ldap.add_entry(entry)
except errors.DuplicateEntry:
logger.debug('cn=servers,cn=dns container already exists')
class DnsBackup:
def __init__(self, service):
self.service = service
self.zones = {}
def add(self, zone, record_type, host, rdata):
"""
Backup a DNS record in the file store so it can later be removed.
"""
if zone not in self.zones:
zone_id = len(self.zones)
self.zones[zone] = (zone_id, 0)
self.service.backup_state("dns_zone_%s" % zone_id, zone)
(zone_id, record_id) = self.zones[zone]
self.service.backup_state("dns_record_%s_%s" % (zone_id, record_id),
"%s %s %s" % (record_type, host, rdata))
self.zones[zone] = (zone_id, record_id + 1)
def clear_records(self, have_ldap):
"""
Remove all records from the file store. If we are connected to
ldap, we will also remove them there.
"""
i = 0
while True:
zone = self.service.restore_state("dns_zone_%s" % i)
if not zone:
return
j = 0
while True:
dns_record = self.service.restore_state("dns_record_%s_%s" % (i, j))
if not dns_record:
break
if have_ldap:
type, host, rdata = dns_record.split(" ", 2)
try:
delkw = { '%srecord' % str(type.lower()) : unicode(rdata) }
api.Command.dnsrecord_del(unicode(zone), unicode(host), **delkw)
except Exception:
pass
j += 1
i += 1
class BindInstance(service.Service):
def __init__(self, fstore=None, api=api):
super(BindInstance, self).__init__(
"named",
service_desc="DNS",
fstore=fstore,
api=api,
service_user=constants.NAMED_USER,
service_prefix=u'DNS',
keytab=paths.NAMED_KEYTAB
)
self.dns_backup = DnsBackup(self)
self.domain = None
self.host = None
self.ip_addresses = []
self.forwarders = None
self.sub_dict = None
self.reverse_zones = []
self.named_regular = services.service('named-regular', api)
suffix = ipautil.dn_attribute_property('_suffix')
def setup(self, fqdn, ip_addresses, realm_name, domain_name, forwarders,
forward_policy, reverse_zones,
named_user=constants.NAMED_USER, zonemgr=None,
no_dnssec_validation=False):
self.service_user = named_user
self.fqdn = fqdn
self.ip_addresses = ip_addresses
self.realm = realm_name
self.domain = domain_name
self.forwarders = forwarders
self.forward_policy = forward_policy
self.host = fqdn.split(".")[0]
self.suffix = ipautil.realm_to_suffix(self.realm)
self.reverse_zones = reverse_zones
self.no_dnssec_validation=no_dnssec_validation
if not zonemgr:
self.zonemgr = 'hostmaster.%s' % normalize_zone(self.domain)
else:
self.zonemgr = normalize_zonemgr(zonemgr)
self.first_instance = not dns_container_exists(self.suffix)
self.__setup_sub_dict()
@property
def host_domain(self):
return self.fqdn.split(".", 1)[1]
@property
def host_in_rr(self):
# when a host is not in a default domain, it needs to be referred
# with FQDN and not in a domain-relative host name
if not self.host_in_default_domain():
return normalize_zone(self.fqdn)
return self.host
def host_in_default_domain(self):
return normalize_zone(self.host_domain) == normalize_zone(self.domain)
def create_file_with_system_records(self):
system_records = IPASystemRecords(self.api, all_servers=True)
text = u'\n'.join(
IPASystemRecords.records_list_from_zone(
system_records.get_base_records()
)
)
with tempfile.NamedTemporaryFile(
mode="w", prefix="ipa.system.records.",
suffix=".db", delete=False
) as f:
f.write(text)
print("Please add records in this file to your DNS system:",
f.name)
def create_instance(self):
try:
self.stop()
except Exception:
pass
for ip_address in self.ip_addresses:
if installutils.record_in_hosts(str(ip_address), self.fqdn) is None:
installutils.add_record_to_hosts(str(ip_address), self.fqdn)
# Make sure generate-rndc-key.sh runs before named restart
self.step("generating rndc key file", self.__generate_rndc_key)
if self.first_instance:
self.step("adding DNS container", self.__setup_dns_container)
if not dns_zone_exists(self.domain, self.api):
self.step("setting up our zone", self.__setup_zone)
if self.reverse_zones:
self.step("setting up reverse zone", self.__setup_reverse_zone)
self.step("setting up our own record", self.__add_self)
if self.first_instance:
self.step("setting up records for other masters", self.__add_others)
# all zones must be created before this step
self.step("adding NS record to the zones", self.__add_self_ns)
self.step("setting up kerberos principal", self.__setup_principal)
self.step("setting up named.conf", self.__setup_named_conf)
self.step("setting up server configuration",
self.__setup_server_configuration)
# named has to be started after softhsm initialization
# self.step("restarting named", self.__start)
self.step("configuring named to start on boot", self.__enable)
self.step("changing resolv.conf to point to ourselves", self.__setup_resolv_conf)
self.start_creation()
def start_named(self):
self.print_msg("Restarting named")
self.__start()
def __start(self):
try:
if self.get_state("running") is None:
# first time store status
self.backup_state("running", self.is_running())
self.restart()
except Exception as e:
logger.error("Named service failed to start (%s)", e)
print("named service failed to start")
def __enable(self):
if self.get_state("enabled") is None:
self.backup_state("enabled", self.is_running())
self.backup_state("named-regular-enabled",
self.named_regular.is_running())
# We do not let the system start IPA components on its own,
# Instead we reply on the IPA init script to start only enabled
# components as found in our LDAP configuration tree
try:
self.ldap_configure('DNS', self.fqdn, None, self.suffix)
except errors.DuplicateEntry:
# service already exists (forced DNS reinstall)
# don't crash, just report error
logger.error("DNS service already exists")
# disable named, we need to run named-pkcs11 only
if self.get_state("named-regular-running") is None:
# first time store status
self.backup_state("named-regular-running",
self.named_regular.is_running())
try:
self.named_regular.stop()
except Exception as e:
logger.debug("Unable to stop named (%s)", e)
try:
self.named_regular.mask()
except Exception as e:
logger.debug("Unable to mask named (%s)", e)
def __setup_sub_dict(self):
if paths.NAMED_CRYPTO_POLICY_FILE is not None:
crypto_policy = 'include "{}";'.format(
paths.NAMED_CRYPTO_POLICY_FILE
)
else:
crypto_policy = "// not available"
self.sub_dict = dict(
FQDN=self.fqdn,
SERVER_ID=ipaldap.realm_to_serverid(self.realm),
SUFFIX=self.suffix,
BINDKEYS_FILE=paths.NAMED_BINDKEYS_FILE,
MANAGED_KEYS_DIR=paths.NAMED_MANAGED_KEYS_DIR,
ROOT_KEY=paths.NAMED_ROOT_KEY,
NAMED_KEYTAB=self.keytab,
RFC1912_ZONES=paths.NAMED_RFC1912_ZONES,
NAMED_PID=paths.NAMED_PID,
NAMED_VAR_DIR=paths.NAMED_VAR_DIR,
BIND_LDAP_SO=paths.BIND_LDAP_SO,
INCLUDE_CRYPTO_POLICY=crypto_policy,
CUSTOM_CONFIG=paths.NAMED_CUSTOM_CONFIG,
NAMED_DATA_DIR=constants.NAMED_DATA_DIR,
NAMED_ZONE_COMMENT=constants.NAMED_ZONE_COMMENT,
)
def __setup_dns_container(self):
self._ldap_mod("dns.ldif", self.sub_dict)
self.__fix_dns_privilege_members()
def __fix_dns_privilege_members(self):
ldap = self.api.Backend.ldap2
cn = 'Update PBAC memberOf %s' % time.time()
task_dn = DN(('cn', cn), ('cn', 'memberof task'), ('cn', 'tasks'),
('cn', 'config'))
basedn = DN(self.api.env.container_privilege, self.api.env.basedn)
entry = ldap.make_entry(
task_dn,
objectclass=['top', 'extensibleObject'],
cn=[cn],
basedn=[basedn],
filter=['(objectclass=*)'],
ttl=[10])
ldap.add_entry(entry)
start_time = time.time()
while True:
try:
task = ldap.get_entry(task_dn)
except errors.NotFound:
break
if 'nstaskexitcode' in task:
break
time.sleep(1)
if time.time() > (start_time + 60):
raise errors.TaskTimeout(task='memberof', task_dn=task_dn)
def __setup_zone(self):
# Always use force=True as named is not set up yet
add_zone(self.domain, self.zonemgr, dns_backup=self.dns_backup,
ns_hostname=self.api.env.host, force=True,
skip_overlap_check=True, api=self.api)
add_rr(self.domain, "_kerberos", "TXT", self.realm, api=self.api)
def __add_self_ns(self):
# add NS record to all zones
ns_hostname = normalize_zone(self.api.env.host)
result = self.api.Command.dnszone_find()
for zone in result['result']:
zone = unicode(zone['idnsname'][0]) # we need unicode due to backup
logger.debug("adding self NS to zone %s apex", zone)
add_ns_rr(zone, ns_hostname, self.dns_backup, force=True,
api=self.api)
def __setup_reverse_zone(self):
# Always use force=True as named is not set up yet
for reverse_zone in self.reverse_zones:
add_zone(reverse_zone, self.zonemgr, ns_hostname=self.api.env.host,
dns_backup=self.dns_backup, force=True,
skip_overlap_check=True, api=self.api)
def __add_master_records(self, fqdn, addrs):
host, zone = fqdn.split(".", 1)
# Add forward and reverse records to self
for addr in addrs:
# Check first if the zone is a master zone
# (if it is a forward zone, dns_zone_exists will return False)
if dns_zone_exists(zone, api=self.api):
add_fwd_rr(zone, host, addr, self.api)
else:
logger.debug("Skip adding record %s to a zone %s "
"not managed by IPA", addr, zone)
reverse_zone = find_reverse_zone(addr, self.api)
if reverse_zone:
add_ptr_rr(reverse_zone, addr, fqdn, None, api=self.api)
def __add_self(self):
self.__add_master_records(self.fqdn, self.ip_addresses)
def __add_others(self):
entries = api.Backend.ldap2.get_entries(
DN(api.env.container_masters, self.suffix),
api.Backend.ldap2.SCOPE_ONELEVEL, None, ['dn'])
for entry in entries:
fqdn = entry.dn[0]['cn']
if fqdn == self.fqdn:
continue
addrs = installutils.resolve_ip_addresses_nss(fqdn)
logger.debug("Adding DNS records for master %s", fqdn)
self.__add_master_records(fqdn, addrs)
def __setup_principal(self):
installutils.kadmin_addprinc(self.principal)
# Store the keytab on disk
self.fstore.backup_file(self.keytab)
installutils.create_keytab(self.keytab, self.principal)
p = self.move_service(self.principal)
if p is None:
# the service has already been moved, perhaps we're doing a DNS reinstall
dns_principal = DN(('krbprincipalname', self.principal),
('cn', 'services'), ('cn', 'accounts'), self.suffix)
else:
dns_principal = p
# Make sure access is strictly reserved to the named user
pent = pwd.getpwnam(self.service_user)
os.chown(self.keytab, pent.pw_uid, pent.pw_gid)
os.chmod(self.keytab, 0o400)
# modify the principal so that it is marked as an ipa service so that
# it can host the memberof attribute, then also add it to the
# dnsserver role group, this way the DNS is allowed to perform
# DNS Updates
dns_group = DN(('cn', 'DNS Servers'), ('cn', 'privileges'), ('cn', 'pbac'), self.suffix)
mod = [(ldap.MOD_ADD, 'member', dns_principal)]
try:
api.Backend.ldap2.modify_s(dns_group, mod)
except ldap.TYPE_OR_VALUE_EXISTS:
pass
except Exception as e:
logger.critical("Could not modify principal's %s entry: %s",
dns_principal, str(e))
raise
# bind-dyndb-ldap persistent search feature requires both size and time
# limit-free connection
mod = [(ldap.MOD_REPLACE, 'nsTimeLimit', '-1'),
(ldap.MOD_REPLACE, 'nsSizeLimit', '-1'),
(ldap.MOD_REPLACE, 'nsIdleTimeout', '-1'),
(ldap.MOD_REPLACE, 'nsLookThroughLimit', '-1')]
try:
api.Backend.ldap2.modify_s(dns_principal, mod)
except Exception as e:
logger.critical("Could not set principal's %s LDAP limits: %s",
dns_principal, str(e))
raise
def __setup_named_conf(self):
if not self.fstore.has_file(paths.NAMED_CONF):
self.fstore.backup_file(paths.NAMED_CONF)
named_txt = ipautil.template_file(
os.path.join(paths.USR_SHARE_IPA_DIR, "bind.named.conf.template"),
self.sub_dict)
named_fd = open(paths.NAMED_CONF, 'w')
named_fd.seek(0)
named_fd.truncate(0)
named_fd.write(named_txt)
named_fd.close()
named_add_ext_conf_file(paths.NAMED_CUSTOM_CFG_SRC,
paths.NAMED_CUSTOM_CONFIG)
if self.no_dnssec_validation:
# disable validation
named_conf_set_directive("dnssec-validation", "no",
section=NAMED_SECTION_OPTIONS,
str_val=False)
# prevent repeated upgrade on new installs
sysupgrade.set_upgrade_state(
'named.conf',
'forward_policy_conflict_with_empty_zones_handled', True
)
def __setup_server_configuration(self):
ensure_dnsserver_container_exists(api.Backend.ldap2, self.api)
try:
self.api.Command.dnsserver_add(
self.fqdn, idnssoamname=DNSName(self.fqdn).make_absolute(),
)
except errors.DuplicateEntry:
# probably reinstallation of DNS
pass
try:
self.api.Command.dnsserver_mod(
self.fqdn,
idnsforwarders=[unicode(f) for f in self.forwarders],
idnsforwardpolicy=unicode(self.forward_policy)
)
except errors.EmptyModlist:
pass
sysupgrade.set_upgrade_state('dns', 'server_config_to_ldap', True)
def __setup_resolv_conf(self):
searchdomains = [self.domain]
nameservers = []
for ip_address in self.ip_addresses:
if ip_address.version == 4:
nameservers.append("127.0.0.1")
elif ip_address.version == 6:
nameservers.append("::1")
try:
tasks.configure_dns_resolver(
nameservers, searchdomains, fstore=self.fstore
)
except IOError as e:
logger.error('Could not update DNS config: %s', e)
else:
# python DNS might have global resolver cached in this variable
# we have to re-initialize it because resolv.conf has changed
dns.resolver.reset_default_resolver()
def __generate_rndc_key(self):
installutils.check_entropy()
ipautil.run([paths.GENERATE_RNDC_KEY])
def add_master_dns_records(self, fqdn, ip_addresses, realm_name, domain_name,
reverse_zones):
self.fqdn = fqdn
self.ip_addresses = ip_addresses
self.realm = realm_name
self.domain = domain_name
self.host = fqdn.split(".")[0]
self.suffix = ipautil.realm_to_suffix(self.realm)
self.reverse_zones = reverse_zones
self.first_instance = False
self.zonemgr = 'hostmaster.%s' % self.domain
self.__add_self()
def remove_ipa_ca_cnames(self, domain_name):
# get ipa-ca CNAMEs
try:
cnames = get_rr(domain_name, IPA_CA_RECORD, "CNAME", api=self.api)
except errors.NotFound:
# zone does not exists
cnames = None
if not cnames:
return
logger.info('Removing IPA CA CNAME records')
# create CNAME to FQDN mapping
cname_fqdn = {}
for cname in cnames:
if cname.endswith('.'):
fqdn = cname[:-1]
else:
fqdn = '%s.%s' % (cname, domain_name)
cname_fqdn[cname] = fqdn
# get FQDNs of all IPA masters
try:
masters = set(get_masters(self.api.Backend.ldap2))
except errors.NotFound:
masters = set()
# check if all CNAMEs point to IPA masters
for cname in cnames:
fqdn = cname_fqdn[cname]
if fqdn not in masters:
logger.warning(
"Cannot remove IPA CA CNAME please remove them manually "
"if necessary")
return
# delete all CNAMEs
for cname in cnames:
del_rr(domain_name, IPA_CA_RECORD, "CNAME", cname, api=self.api)
def remove_master_dns_records(self, fqdn, realm_name, domain_name):
host, zone = fqdn.split(".", 1)
self.host = host
self.fqdn = fqdn
self.domain = domain_name
if not dns_zone_exists(zone, api=self.api):
# Zone may be a forward zone, skip update
return
areclist = get_fwd_rr(zone, host, api=self.api)
for rdata in areclist:
del_fwd_rr(zone, host, rdata, api=self.api)
rzone = find_reverse_zone(rdata)
if rzone is not None:
record = get_reverse_record_name(rzone, rdata)
del_rr(rzone, record, "PTR", normalize_zone(fqdn),
api=self.api)
self.update_system_records()
def remove_server_ns_records(self, fqdn):
"""
Remove all NS records pointing to this server
"""
ldap = self.api.Backend.ldap2
ns_rdata = normalize_zone(fqdn)
# find all NS records pointing to this server
search_kw = {}
search_kw['nsrecord'] = ns_rdata
attr_filter = ldap.make_filter(search_kw, rules=ldap.MATCH_ALL)
attributes = ['idnsname', 'objectclass']
dn = DN(self.api.env.container_dns, self.api.env.basedn)
entries, _truncated = ldap.find_entries(
attr_filter, attributes, base_dn=dn)
# remove records
if entries:
logger.debug("Removing all NS records pointing to %s:", ns_rdata)
for entry in entries:
if 'idnszone' in entry['objectclass']:
# zone record
zone = entry.single_value['idnsname']
logger.debug("zone record %s", zone)
del_ns_rr(zone, u'@', ns_rdata, api=self.api)
else:
zone = entry.dn[1].value # get zone from DN
record = entry.single_value['idnsname']
logger.debug("record %s in zone %s", record, zone)
del_ns_rr(zone, record, ns_rdata, api=self.api)
def update_system_records(self):
self.print_msg("Updating DNS system records")
system_records = IPASystemRecords(self.api)
try:
(
(_ipa_rec, failed_ipa_rec),
(_loc_rec, failed_loc_rec)
) = system_records.update_dns_records()
except IPADomainIsNotManagedByIPAError:
logger.error(
"IPA domain is not managed by IPA, please update records "
"manually")
else:
if failed_ipa_rec or failed_loc_rec:
logger.error("Update of following records failed:")
for attr in (failed_ipa_rec, failed_loc_rec):
for rname, node, error in attr:
for record in IPASystemRecords.records_list_from_node(
rname, node
):
logger.error("%s (%s)", record, error)
def check_global_configuration(self):
"""
Check global DNS configuration in LDAP server and inform user when it
set and thus overrides his configured options in named.conf.
"""
result = self.api.Command.dnsconfig_show()
global_conf_set = any(
param.name in result['result'] for param in
self.api.Object['dnsconfig'].params() if
u'virtual_attribute' not in param.flags
)
if not global_conf_set:
print("Global DNS configuration in LDAP server is empty")
print("You can use 'dnsconfig-mod' command to set global DNS options that")
print("would override settings in local named.conf files")
return
print("Global DNS configuration in LDAP server is not empty")
print("The following configuration options override local settings in named.conf:")
print("")
textui = ipalib.cli.textui(self.api)
self.api.Command.dnsconfig_show.output_for_cli(textui, result, None,
reverse=False)
def is_configured(self):
"""
Override the default logic querying StateFile for configuration status
and look whether named.conf was already modified by IPA installer.
"""
return named_conf_exists()
def uninstall(self):
if self.is_configured():
self.print_msg("Unconfiguring %s" % self.service_name)
running = self.restore_state("running")
enabled = self.restore_state("enabled")
named_regular_running = self.restore_state("named-regular-running")
named_regular_enabled = self.restore_state("named-regular-enabled")
self.dns_backup.clear_records(self.api.Backend.ldap2.isconnected())
try:
self.fstore.restore_file(paths.NAMED_CONF)
except ValueError as error:
logger.debug('%s', error)
try:
tasks.unconfigure_dns_resolver(fstore=self.fstore)
except Exception:
logger.exception("Failed to unconfigure DNS resolver")
ipautil.rmtree(paths.BIND_LDAP_DNS_IPA_WORKDIR)
# disabled by default, by ldap_configure()
if enabled:
self.enable()
else:
self.disable()
if running:
self.restart()
else:
self.stop()
self.named_regular.unmask()
if named_regular_enabled:
self.named_regular.enable()
if named_regular_running:
self.named_regular.start()
ipautil.remove_file(paths.NAMED_CUSTOM_CONFIG)
ipautil.remove_keytab(self.keytab)
ipautil.remove_ccache(run_as=self.service_user)
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