Bug 357181

Description of problem:

After adding some IPv6 zones for unspecified and link-local addresses, I got the
following error crash when trying to start up system-config-bind:

  File "/usr/share/system-config-bind/IPV6.py", line 538, in label
    return self.address.hex_out()
  File "/usr/share/system-config-bind/IPV6.py", line 235, in hex_out
    if(output[-1] == ':'):
IndexError: string index out of range

The problem seems to be with the label generation for the reverse zone, not the
actual load of the zone.

Attempting to create an IPv6 reverse zone with a /16 prefix through the GUI
fails with a different error, also apparently related to label generation:

  File "/usr/share/system-config-bind/NewZone.py", line 141, in response
    fname=s.bind.zone_file(s.zone,str(s.name),True,zoneType)                    
  File "/usr/share/system-config-bind/BIND.py", line 382, in zone_file
    if( fname[-1] == '.'):
IndexError: string index out of range

The minimum supported prefix appears to be /32.

Version-Release number of selected component (if applicable):

4.0.2

How reproducible:

Add the following to named.conf:

zone "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."
 IN {
        // RFC 3513
        type master;
        file "named.empty";
        allow-update { none; };
};

zone "8.e.f.ip6.arpa." IN {
        // RFC 3513
        type master;
        file "named.empty";
};

zone "0.a.e.f.ip6.arpa." IN {
        // RFC 3513
        type master;
        file "named.empty";
};


Steps to Reproduce:
1. add the above to /var/named/chroot/etc/named.conf (or /etc/named.conf)
2. run system-config-bind
3. look at crash traceback
4. patch bug (see attached patch) in /usr/share/system-config-bind/IPV6.py
5. run system-config-bind
6. (try to) create an IPv6 reverse zone for feb0::/16
7. look at error traceback on stderr
8. create an IPv6 reverse zone for feb0:0000::/32
9. look at labels for IPv6 reverse zones
  
Actual results:

:       Internet Reverse IPv6 ARPA Zone
        Internet Reverse IPv6 ARPA Zone
        Internet Reverse IPv6 ARPA Zone
feb0:   Internet Reverse IPv6 ARPA Zone

(note display of all-zeros IPv6 address as ':', and empty label for /12 and /16
zones)

Expected results:

::            Internet Reverse IPv6 ARPA Zone
fe80::/12     Internet Reverse IPv6 ARPA Zone
fea0::/16     Internet Reverse IPv6 ARPA Zone
feb0::/32     Internet Reverse IPv6 ARPA Zone

[or at least, if prefix length display is not possible:]

::            Internet Reverse IPv6 ARPA Zone
fe80::        Internet Reverse IPv6 ARPA Zone
fea0::        Internet Reverse IPv6 ARPA Zone
feb0:0::      Internet Reverse IPv6 ARPA Zone


Additional info:

A basic problem seems to be that the IPv6 reverse zone delegation points
allow zone delegation points at any of /4 /8 /12 /16 /20 etc. but the
system-config-bind configuration dialogs allow only for zones at /16 /32 /48
etc.  To provide full functionality, the IPv6 reverse zone creation dialog
should provide a way to specify the prefix length (as multiple of /4).

As a workaround, you can manually create reverse zones at the finer granularity,
and edit them with system-config-bind, it seems to create entries correctly
(including automatically added reverse entries).  The only problem is the empty
labels for zones with less than /32 (and lack of prefix-length indication).

@alex