Re: [dane] An AD bit discussion

Viktor Dukhovni <viktor1dane@dukhovni.org> Wed, 26 February 2014 18:24 UTC

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Date: Wed, 26 Feb 2014 18:24:32 +0000
From: Viktor Dukhovni <viktor1dane@dukhovni.org>
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Subject: Re: [dane] An AD bit discussion
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On Wed, Feb 26, 2014 at 06:14:09PM +0000, Tony Finch wrote:

> > As for setting the "AD" bit in the request automatically, it probably
> > should still require an explicit indication of interest from the
> > application or be set via a default option value /etc/resolv.conf.
> 
> Perhaps, though I think the AD flag is pretty benign.

I think it requires EDNS0, but if that is already set, perhaps
turning on AD by default is harmless.  This specific detail is
perhaps more of a "dnsop" than "dane" question.

By the way I just noticed that http://www.vpnc.org/getdns-api/
does not define the interaction of DNSSEC with:

    getdns_return_t getdns_context_set_append_name(
	getdns_context *context,
	getdns_append_name_t value );

    Specifies whether to append a suffix to the query string before
    the API starts resolving a name. The value is

	GETDNS_APPEND_NAME_ALWAYS,
	GETDNS_APPEND_NAME_ONLY_TO_SINGLE_LABEL_AFTER_FAILURE,
	GETDNS_APPEND_NAME_ONLY_TO_MULTIPLE_LABEL_NAME_AFTER_FAILURE, or
	GETDNS_APPEND_NAME_NEVER.

    This controls whether or not to append the suffix given by
    getdns_context_set_suffix

Name appending breaks DNSSEC when any of the resulting zones are
insecure and are tried before ultimately secure zones.  The validity
of a request for a secure response for an under-specified query is
IMHO questionable.

-- 
	Viktor.