[PATCH] Re: resolv_wrapper URI RR support - name compression

Matt Rogers mrogers at redhat.com
Thu Aug 25 17:29:59 UTC 2016


On Wed, 2016-08-24 at 08:10 +0200, Andreas Schneider wrote:
> On Tuesday, 23 August 2016 11:41:45 CEST Matt Rogers wrote:
> > 
> > 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.
> 
> Hey Matt,
> 
> thanks for the patches!
> 
> Please add:
> 
> size_t uri_len;
> 
> uri_len = strlen(rr->rrdata.uri_rec.uri) + 1;
> 
> and then use uri_len as we are using it twice.
> 
> Also you need to sign your work. See
> 
> https://www.samba.org/samba/devel/copyright-policy.html
> 
> > 
> > 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.
> 
> We are happy to accept patches to allow to return more than one URI
> :)
> 

Here are patches on top of my previous ones that adds support for
listing multiple URI answers for a query in the fake hosts file, and
updates the tests.

Matt

-------------- next part --------------
A non-text attachment was scrubbed...
Name: rwrap-uri-multi.patch
Type: text/x-patch
Size: 6523 bytes
Desc: not available
URL: <http://lists.samba.org/pipermail/samba-technical/attachments/20160825/ac9ceb53/rwrap-uri-multi.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: rwrap-uri-multi-test.patch
Type: text/x-patch
Size: 2682 bytes
Desc: not available
URL: <http://lists.samba.org/pipermail/samba-technical/attachments/20160825/ac9ceb53/rwrap-uri-multi-test.bin>


More information about the samba-technical mailing list