resolv_wrapper URI RR support - name compression

Matt Rogers mrogers at redhat.com
Tue Aug 23 15:41:45 UTC 2016


On Tue, 2016-08-23 at 15:54 +0200, Andreas Schneider wrote:
> On Monday, 22 August 2016 17:52:25 CEST Matt Rogers wrote:
> > 
> > Hi,
> > 
> > I'm using resolv_wrapper from master at 02535da4 to test krb5 URI
> > RR
> > lookups. Similar to the SRV records, rwrap_fake_uri() runs
> > ns_name_compress() on the result, however URI records contain a
> > formatted entry and not a DNS name, so I don't think that the call
> > to
> > ns_name_compress() is valid here.  The result of running
> > ns_name_compress() on the URI record (which appears as
> > "krb5srv:m:kkdcp:https://kdc/path") is that it adds a " " to the
> > beginning that does not get removed with a subsequent uncompress.
> > Any
> > objections to removing the ns_name_compress/uncompress on URI RR
> > results?
> 
> This means the provided test is incorrect. We need a test which works
> in a 
> real world scenario and also with resolv_wrapper to verify that
> resolv_wrapper 
> is doing everything correctly.
> 
> Could you use the current test, modify it and make sure it works in
> the real 
> world?
> 
> Then we can fix resolve_wrapper ...
> 

I've attached patches for removing the name compression from the URI
result as well as the tests. This gives a correct result for the real
world test.

Another issue is that it can only return a single answer for a URI
query, since it reaches the first matching URI key in the host file and
stops. The krb5 URI lookup collects all answers from a query and parses
the URIs, sorting the results accordingly, so it would be great to be
able to have a fake hosts file with all of the test URIs listed and not
have to test them one by one.

Matt
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