freeipa/ipaserver/install/bindinstance.py

# 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; version 2 only
#
# 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, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#

import tempfile
import os
import pwd
import logging

import installutils
import ldap
import service
from ipaserver import ipaldap
from ipapython import sysrestore
from ipapython import ipautil

import ipalib
from ipalib import api, util, errors

def check_inst(unattended):
    # So far this file is always present in both RHEL5 and Fedora if all the necessary
    # bind packages are installed (RHEL5 requires also the pkg: caching-nameserver)
    if not os.path.exists('/etc/named.rfc1912.zones'):
        print "BIND was not found on this system"
        print "Please install the bind package and start the installation again"
        return False

    # Also check for the LDAP BIND plug-in
    if not os.path.exists('/usr/lib/bind/ldap.so') and \
       not os.path.exists('/usr/lib64/bind/ldap.so'):
        print "The BIND LDAP plug-in was not found on this system"
        print "Please install the bind-dyndb-ldap package and start the installation again"
        return False

    if not unattended and os.path.exists('/etc/named.conf'):
        msg = "Existing BIND configuration detected, overwrite?"
        return ipautil.user_input(msg, False)

    return True

def get_reverse_zone(ip_address):
    tmp = ip_address.split(".")
    tmp.reverse()
    name = tmp.pop(0)
    zone = ".".join(tmp) + ".in-addr.arpa" 

    return zone, name

def add_zone(name, update_policy=None):
    if not update_policy:
        update_policy = "grant %s krb5-self * A;" % api.env.realm

    try:
        api.Command.dns_add(unicode(name),
                            idnssoamname=unicode(api.env.host),
                            idnsallowdynupdate=True,
                            idnsupdatepolicy=unicode(update_policy))
    except (errors.DuplicateEntry, errors.EmptyModlist):
        pass

    add_rr(name, "@", "NS", api.env.host+".")

    return name

def add_reverze_zone(ip_address, update_policy=None):
    zone, name = get_reverse_zone(ip_address)
    if not update_policy:
        update_policy = "grant %s krb5-subdomain %s. PTR;" % (api.env.realm, zone)
    try:
        api.Command.dns_add(unicode(zone),
                            idnssoamname=unicode(api.env.host),
                            idnsallowdynupdate=True,
                            idnsupdatepolicy=unicode(update_policy))
    except (errors.DuplicateEntry, errors.EmptyModlist):
        pass

    add_rr(zone, "@", "NS", api.env.host)

    return zone

def add_rr(zone, name, type, rdata):
    try:
        api.Command.dns_add_rr(unicode(zone), unicode(name),
                               unicode(type), unicode(rdata))
    except (errors.DuplicateEntry, errors.EmptyModlist):
        pass

def add_ptr_rr(ip_address, fqdn):
    zone, name = get_reverse_zone(ip_address)
    add_rr(zone, name, "PTR", fqdn+".")

class BindInstance(service.Service):
    def __init__(self, fstore=None, dm_password=None):
        service.Service.__init__(self, "named", dm_password=dm_password)
        self.named_user = None
        self.fqdn = None
        self.domain = None
        self.host = None
        self.ip_address = None
        self.realm = None
        self.forwarders = None
        self.sub_dict = None

        if fstore:
            self.fstore = fstore
        else:
            self.fstore = sysrestore.FileStore('/var/lib/ipa/sysrestore')

    def setup(self, fqdn, ip_address, realm_name, domain_name, forwarders, ntp, named_user="named"):
        self.named_user = named_user
        self.fqdn = fqdn
        self.ip_address = ip_address
        self.realm = realm_name
        self.domain = domain_name
        self.forwarders = forwarders
        self.host = fqdn.split(".")[0]
        self.suffix = util.realm_to_suffix(self.realm)
        self.ntp = ntp

        tmp = ip_address.split(".")
        tmp.reverse()

        self.reverse_host = tmp.pop(0)
        self.reverse_subnet = ".".join(tmp)

        self.__setup_sub_dict()

    def create_sample_bind_zone(self):
        bind_txt = ipautil.template_file(ipautil.SHARE_DIR + "bind.zone.db.template", self.sub_dict)
        [bind_fd, bind_name] = tempfile.mkstemp(".db","sample.zone.")
        os.write(bind_fd, bind_txt)
        os.close(bind_fd)
        print "Sample zone file for bind has been created in "+bind_name

    def create_instance(self):

        try:
            self.stop()
        except:
            pass

        self.__add_zone_steps()
        self.step("setting up our zone", self.__setup_zone)
        self.step("setting up reverse zone", self.__setup_reverse_zone)

        self.step("setting up kerberos principal", self.__setup_principal)
        self.step("setting up named.conf", self.__setup_named_conf)

        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("Configuring named:")

    def __add_zone_steps(self):
        """
        Add a DNS container if it doesn't exist.
        """

        def object_exists(dn):
            """
            Test whether the given object exists in LDAP.
            """
            try:
                server.search_ext_s(dn, ldap.SCOPE_BASE)
            except ldap.NO_SUCH_OBJECT:
                return False
            else:
                return True

        server = ldap.initialize("ldap://" + self.fqdn)
        server.simple_bind_s()

        if not object_exists("cn=dns,%s" % self.suffix):
            self.step("adding DNS container", self.__setup_dns_container)

        server.unbind_s()

    def __start(self):
        try:
            self.backup_state("running", self.is_running())
            self.restart()
        except:
            print "named service failed to start"

    def __enable(self):
        self.backup_state("enabled", self.is_running())
        self.chkconfig_on()

    def __setup_sub_dict(self):
        if self.forwarders:
            fwds = "\n"
            for forwarder in self.forwarders:
                fwds += "\t\t%s;\n" % forwarder
            fwds += "\t"
        else:
            fwds = " "

        if self.ntp:
            optional_ntp =  "\n;ntp server\n"
            optional_ntp += "_ntp._udp\t\tIN SRV 0 100 123\t%s""" % self.host
        else:
            optional_ntp = ""

        self.sub_dict = dict(FQDN=self.fqdn,
                             IP=self.ip_address,
                             DOMAIN=self.domain,
                             HOST=self.host,
                             REALM=self.realm,
                             FORWARDERS=fwds,
                             SUFFIX=self.suffix,
                             OPTIONAL_NTP=optional_ntp)

    def __setup_dns_container(self):
        self._ldap_mod("dns.ldif", self.sub_dict)

    def __setup_zone(self):
        resource_records = (
            (self.host, "A", self.ip_address),
            ("_ldap._tcp", "SRV", "0 100 389 %s" % self.host),
            ("_kerberos", "TXT", self.realm),
            ("_kerberos._tcp", "SRV", "0 100 88 %s" % self.host),
            ("_kerberos._udp", "SRV", "0 100 88 %s" % self.host),
            ("_kerberos-master._tcp", "SRV", "0 100 88 %s" % self.host),
            ("_kerberos-master._udp", "SRV", "0 100 88 %s" % self.host),
            ("_kpasswd._tcp", "SRV", "0 100 464 %s" % self.host),
            ("_kpasswd._udp", "SRV", "0 100 464 %s" % self.host),
        )

        zone = add_zone(self.domain)
        for (host, type, rdata) in resource_records:
            add_rr(zone, host, type, rdata)
        if self.ntp:
            add_rr(zone, "_ntp._udp", "SRV", "0 100 123 "+self.host)

    def __setup_reverse_zone(self):
        add_reverze_zone(self.ip_address)
        add_ptr_rr(self.ip_address, self.fqdn)

    def __setup_principal(self):
        dns_principal = "DNS/" + self.fqdn + "@" + self.realm
        installutils.kadmin_addprinc(dns_principal)

        # Store the keytab on disk
        self.fstore.backup_file("/etc/named.keytab")
        installutils.create_keytab("/etc/named.keytab", dns_principal)
        dns_principal = self.move_service(dns_principal)

        # Make sure access is strictly reserved to the named user
        pent = pwd.getpwnam(self.named_user)
        os.chown("/etc/named.keytab", pent.pw_uid, pent.pw_gid)
        os.chmod("/etc/named.keytab", 0400)

        # 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
        conn = None

        try:
            conn = ipaldap.IPAdmin("127.0.0.1")
            conn.simple_bind_s("cn=directory manager", self.dm_password)
        except Exception, e:
            logging.critical("Could not connect to the Directory Server on %s" % self.fqdn)
            raise e

        dns_group = "cn=dnsserver,cn=rolegroups,cn=accounts,%s" % self.suffix
        mod = [(ldap.MOD_ADD, 'member', dns_principal)]

        try:
            conn.modify_s(dns_group, mod)
        except Exception, e:
            logging.critical("Could not modify principal's %s entry" % dns_principal)
            raise e

        conn.unbind()

    def __setup_named_conf(self):
        self.fstore.backup_file('/etc/named.conf')
        named_txt = ipautil.template_file(ipautil.SHARE_DIR + "bind.named.conf.template", self.sub_dict)
        named_fd = open('/etc/named.conf', 'w')
        named_fd.seek(0)
        named_fd.truncate(0)
        named_fd.write(named_txt)
        named_fd.close()

    def __setup_resolv_conf(self):
        self.fstore.backup_file('/etc/resolv.conf')
        resolv_txt = "search "+self.domain+"\nnameserver "+self.ip_address+"\n"
        resolv_fd = open('/etc/resolv.conf', 'w')
        resolv_fd.seek(0)
        resolv_fd.truncate(0)
        resolv_fd.write(resolv_txt)
        resolv_fd.close()

    def uninstall(self):
        running = self.restore_state("running")
        enabled = self.restore_state("enabled")

        if not running is None:
            self.stop()

        for f in ["/etc/named.conf", "/etc/resolv.conf"]:
            try:
                self.fstore.restore_file(f)
            except ValueError, error:
                logging.debug(error)
                pass

        if not enabled is None and not enabled:
            self.chkconfig_off()

        if not running is None and running:
            self.start()