[bind10-dev] ddns

[JINMEI Tatuya / 神明達哉]

At Wed, 30 Nov 2011 11:35:10 +0100,
Shane Kerr <shane at isc.org> wrote:

> > Is that a known problem or your opinion?  I don't think it causes any
> > essential leakage of information that cannot be retrieved otherwise.
> > For example, if you want to know whether a particular server has
> > authority for a particular zone, you can simply send an SOA query for
> > that zone name to that server.  I believe other information that could
> > be "leaked" via prerequisite failures can also be retrieved via simple
> > normal queries.
> 
> Hm... this is based on a vague memory of mine. I went back through the
> BIND 9 changelog and didn't seen anything related to this, so perhaps I
> am crazy. :( IIRC Michael knows this particular issue in detail.

It's probably this one:

2737.	[func]		UPDATE requests can leak existence information.
			[RT #17261]

The related code is this:

static void
update_action(isc_task_t *task, isc_event_t *event) {
[...]
	/*
	 * Update message processing can leak record existance information
	 * so check that we are allowed to query this zone.  Additionally
	 * if we would refuse all updates for this zone we bail out here.
	 */
	CHECK(checkqueryacl(client, dns_zone_getqueryacl(zone), zonename,
			    dns_zone_getupdateacl(zone), ssutable));

---
JINMEI, Tatuya