Process relative nameserver DNS record correctly

Nameserver hostname passed to dnszone_add command was always treated
as FQDN even though it was a relative DNS name to the new zone. All
relative names were being rejected as unresolvable.

Modify --name-server option processing in dnszone_add and dnszone_mod
to respect FQDN/relative DNS name and do the checks accordingly. With
this change, user can add a new zone "example.com" and let dnszone_add
to create NS record "ns" in it, when supplied with its IP address. IP
address check is more strict so that it is not entered when no forward
record is created. Places misusing the option were fixed.

Nameserver option now also accepts zone name, which means that NS and A
record is placed to DNS zone itself. Also "@" is accepted as a nameserver
name, BIND understand it also as a zone name. As a side-effect of this
change, other records with hostname part (MX, KX, NS, SRV) accept "@"
as valid hostname. BIND replaces it with respective zone name as well.

Unit tests were updated to test the new format.

https://fedorahosted.org/freeipa/ticket/3204

1 files changed, 93 insertions, 18 deletions

diff --git a/ipalib/plugins/dns.py b/ipalib/plugins/dns.py
index febd4d17c..e7ac58d23 100644
--- a/ipalib/plugins/dns.py
+++ b/ipalib/plugins/dns.py
@@ -31,7 +31,7 @@ from ipalib import Command
 from ipalib.parameters import Flag, Bool, Int, Decimal, Str, StrEnum, Any
 from ipalib.plugins.baseldap import *
 from ipalib import _, ngettext
-from ipalib.util import (validate_zonemgr, normalize_zonemgr,
+from ipalib.util import (validate_zonemgr, normalize_zonemgr, normalize_zone,
         validate_hostname, validate_dns_label, validate_domain_name,
         get_dns_forward_zone_update_policy, get_dns_reverse_zone_update_policy,
         get_reverse_zone_default, zone_is_reverse, REVERSE_DNS_ZONES)
@@ -72,8 +72,9 @@ ipa dnsrecord-mod --mx-rec="0 mx.example.com." --mx-preference=1
 EXAMPLES:
 
  Add new zone:
-   ipa dnszone-add example.com --name-server=nameserver.example.com \\
-                               --admin-email=admin@example.com
+   ipa dnszone-add example.com --name-server=ns \\
+                               --admin-email=admin@example.com \\
+                               --ip-address=10.0.0.1
 
  Add system permission that can be used for per-zone privilege delegation:
    ipa dnszone-add-permission example.com
@@ -90,7 +91,7 @@ EXAMPLES:
 
  Add new reverse zone specified by network IP address:
    ipa dnszone-add --name-from-ip=80.142.15.0/24 \\
-                   --name-server=nameserver.example.com
+                   --name-server=ns.example.com.
 
  Add second nameserver for example.com:
    ipa dnsrecord-add example.com @ --ns-rec=nameserver2.example.com
@@ -357,6 +358,8 @@ def _normalize_bind_aci(bind_acis):
     return acis
 
 def _bind_hostname_validator(ugettext, value):
+    if value == _dns_zone_record:
+        return
     try:
         # Allow domain name which is not fully qualified. These are supported
         # in bind and then translated as <non-fqdn-name>.<domain>.
@@ -1500,7 +1503,9 @@ _dns_supported_record_types = tuple(record.rrtype for record in _dns_records \
                                     if record.supported)
 
 def check_ns_rec_resolvable(zone, name):
-    if not name.endswith('.'):
+    if name == _dns_zone_record:
+        name = normalize_zone(zone)
+    elif not name.endswith('.'):
         # this is a DNS name relative to the zone
         zone = dns.name.from_text(zone)
         name = unicode(dns.name.from_text(name, origin=zone))
@@ -1567,6 +1572,7 @@ class dnszone(LDAPObject):
             cli_name='name_server',
             label=_('Authoritative nameserver'),
             doc=_('Authoritative nameserver domain name'),
+            normalizer=lambda value: value.lower(),
         ),
         Str('idnssoarname',
             _rname_validator,
@@ -1716,6 +1722,38 @@ class dnszone(LDAPObject):
     def permission_name(self, zone):
         return u"Manage DNS zone %s" % zone
 
+    def get_name_in_zone(self, zone, hostname):
+        """
+        Get name of a record that is to be added to a new zone. I.e. when
+        we want to add record "ipa.lab.example.com" in a zone "example.com",
+        this function should return "ipa.lab". Returns None when record cannot
+        be added to a zone
+        """
+        if hostname == _dns_zone_record:
+            # special case: @ --> zone name
+            return hostname
+
+        if hostname.endswith(u'.'):
+            hostname = hostname[:-1]
+        if zone.endswith(u'.'):
+            zone = zone[:-1]
+
+        hostname_parts = hostname.split(u'.')
+        zone_parts = zone.split(u'.')
+
+        dns_name = list(hostname_parts)
+        for host_part, zone_part in zip(reversed(hostname_parts),
+                                        reversed(zone_parts)):
+            if host_part != zone_part:
+                return None
+            dns_name.pop()
+
+        if not dns_name:
+            # hostname is directly in zone itself
+            return _dns_zone_record
+
+        return u'.'.join(dns_name)
+
 api.register(dnszone)
 
 
@@ -1726,10 +1764,10 @@ class dnszone_add(LDAPCreate):
     takes_options = LDAPCreate.takes_options + (
         Flag('force',
              label=_('Force'),
-             doc=_('Force DNS zone creation even if nameserver not in DNS.'),
+             doc=_('Force DNS zone creation even if nameserver is not resolvable.'),
         ),
         Str('ip_address?', _validate_ipaddr,
-            doc=_('Add the nameserver to DNS with this IP address'),
+            doc=_('Add forward record for nameserver located in the created zone'),
         ),
     )
 
@@ -1746,13 +1784,32 @@ class dnszone_add(LDAPCreate):
         # NS record must contain domain name
         if valid_ip(nameserver):
             raise errors.ValidationError(name='name-server',
-                    error=unicode(_("Nameserver address is not a fully qualified domain name")))
+                    error=_("Nameserver address is not a domain name"))
 
-        if nameserver[-1] != '.':
-            nameserver += '.'
+        nameserver_ip_address = options.get('ip_address')
+        normalized_zone = normalize_zone(keys[-1])
 
-        if not 'ip_address' in options and not options['force']:
-            check_ns_rec_resolvable(keys[0], nameserver)
+        if nameserver.endswith('.'):
+            record_in_zone = self.obj.get_name_in_zone(keys[-1], nameserver)
+        else:
+            record_in_zone = nameserver
+
+        if zone_is_reverse(normalized_zone):
+            if not nameserver.endswith('.'):
+                raise errors.ValidationError(name='name-server',
+                        error=_("Nameserver for reverse zone cannot be "
+                                "a relative DNS name"))
+            elif nameserver_ip_address:
+                raise errors.ValidationError(name='ip_address',
+                        error=_("Nameserver DNS record is created for "
+                                "for forward zones only"))
+        elif nameserver_ip_address and nameserver.endswith('.') and not record_in_zone:
+            raise errors.ValidationError(name='ip_address',
+                    error=_("Nameserver DNS record is created only for "
+                            "nameservers in current zone"))
+
+        if not nameserver_ip_address and not options['force']:
+             check_ns_rec_resolvable(keys[0], nameserver)
 
         entry_attrs['nsrecord'] = nameserver
         entry_attrs['idnssoamname'] = nameserver
@@ -1760,12 +1817,16 @@ class dnszone_add(LDAPCreate):
 
     def post_callback(self, ldap, dn, entry_attrs, *keys, **options):
         assert isinstance(dn, DN)
-        if 'ip_address' in options:
-            nameserver = entry_attrs['idnssoamname'][0][:-1] # ends with a dot
-            nsparts = nameserver.split('.')
-            add_forward_record('.'.join(nsparts[1:]),
-                               nsparts[0],
-                               options['ip_address'])
+        nameserver_ip_address = options.get('ip_address')
+        if nameserver_ip_address:
+            nameserver = entry_attrs['idnssoamname'][0]
+            if nameserver.endswith('.'):
+                dns_record = self.obj.get_name_in_zone(keys[-1], nameserver)
+            else:
+                dns_record = nameserver
+            add_forward_record(keys[-1],
+                               dns_record,
+                               nameserver_ip_address)
 
         return dn
 
@@ -1789,8 +1850,22 @@ api.register(dnszone_del)
 class dnszone_mod(LDAPUpdate):
     __doc__ = _('Modify DNS zone (SOA record).')
 
+    takes_options = LDAPUpdate.takes_options + (
+        Flag('force',
+             label=_('Force'),
+             doc=_('Force nameserver change even if nameserver not in DNS'),
+        ),
+    )
+
     has_output_params = LDAPUpdate.has_output_params + dnszone_output_params
 
+    def pre_callback(self, ldap, dn, entry_attrs, attrs_list,  *keys, **options):
+        nameserver = entry_attrs.get('idnssoamname')
+        if nameserver and nameserver != _dns_zone_record and not options['force']:
+            check_ns_rec_resolvable(keys[0], nameserver)
+
+        return dn
+
 api.register(dnszone_mod)