Fix Basic01

[tgreenx]

Purpose

This PR updates Basic01 to make use of the correct variables due to an oversight in the initial implementation update (#1212).

This would happen when a referral points to out-of-bailiwick name servers for a zone that isn’t the zone to test, but some parent of it. See comment below.

Context

Fixes #1280

How to test this PR

$ zonemaster-cli --show-testcase --test Basic/basic01 --level INFO --raw 0.0.9.0.0.0.7.0.1.0.0.2.ip6.arpa
   0.00 INFO     UNSPECIFIED    GLOBAL_VERSION   version=v4.7.2
  20.06 INFO     BASIC01        B01_PARENT_FOUND   domain=0.0.7.0.1.0.0.2.ip6.arpa; ns_ip_list=nac.no/128.39.2.22;nac.no/2001:700:0:102::aa53;nn.uninett.no/158.38.0.181;nn.uninett.no/2001:700:0:503::aa:5302;ns.uninett.no/158.38.3.139;ns.uninett.no/2001:700:1:12::3:139;server.nordu.net/193.10.252.19;server.nordu.net/2001:948:4:2::19
  20.07 INFO     BASIC01        B01_CHILD_FOUND   domain=0.0.9.0.0.0.7.0.1.0.0.2.ip6.arpa

[matsduf]

Is this a candidate for a fix version?

[matsduf]

This would impact any zone for which name servers give referral responses with missing glue.

To me "missing" means that there should be glue, but it is not there. If I have understood it correctly, it impacts a zone for which the referrals are without glue, which is how it should be in many cases.

Especially for reverse zones, in-bailiwick NS are not expected. If there is no in-bailiwick NS, glue is not needed.

[matsduf]

Can this PR be merged?

[matsduf]

@tgreenx, can the description be updated to make it clearer what zones were impacted. I feel "any zone for which name servers give referral responses with missing glue" is not fully correct. See 0-24.se which has no glue in delegation (referral) but it is not impacted.

[marc-vanderwal]

@tgreenx, can the description be updated to make it clearer what zones were impacted. I feel "any zone for which name servers give referral responses with missing glue" is not fully correct. See 0-24.se which has no glue in delegation (referral) but it is not impacted.

I’ve included a suggestion here: zonemaster/zonemaster#1201 (review)

[marc-vanderwal]

Just to make things clear: the issue only happens when a referral points to out-of-bailiwick name servers for a zone that isn’t the zone to test, but some parent of it.

Firstly, testing ip6.arpa does not exhibit the problem because the first delegation is from the root to arpa, which has in-bailiwick name servers with glue, then to ip6.arpa—the zone we are testing.

Secondly, testing 7.0.1.0.0.2.ip6.arpa also does not exhibit the problem, because the delegation from arpa to ip6.arpa has out-of-bailiwick name servers but contains glue records. Then, there is a delegation from ip6.arpa to 7.0.1.0.0.2.ip6.arpa—the zone we are testing.

Finally, testing 0.0.9.0.0.0.7.0.1.0.0.2.ip6.arpa does exhibit the problem. That’s because the delegation from ip6.arpa to 7.0.1.0.0.2.ip6.arpa, which is a parent of the zone to test, has out-of-bailiwick name servers without glue records. The code then failed to obtain IPv4 and IPv6 addresses for the listed name servers.

In short, the presence or lack of glue was not a problem if the referral pointed to the zone under test. If not, then the bug happened.