[Freeipa-devel] DNSSEC design page: key wrapping

Simo Sorce simo at redhat.com
Wed Mar 5 13:21:13 UTC 2014


On Wed, 2014-03-05 at 10:53 +0100, Petr Spacek wrote:
> On 5.3.2014 08:48, Jan Cholasta wrote:
> > On 5.3.2014 05:10, Simo Sorce wrote:
> >> On Tue, 2014-03-04 at 18:32 -0500, Dmitri Pal wrote:
> >>> Remote means that there is a PKCS#11 library that can be loaded into a
> >>> process and would remotely connect to a central server via
> >>> LDAP/REST/whatever. My point is that library should be light weight
> >>> and always talk to a local service like SSSD rather than have a remote
> >>> interface. In this case SSSD on the server can talk to the vault or
> >>> IPA LDAP directly and all consumers would use PKCS#11 interface
> >>> exposed by SSSD
> >>>
> >>> Something like this...
> >>
> >> Yes this is the setting we are discussing, the actual specific
> >> discussion is how SSSD gets the information.
> >>
> >> Honza proposed to use a PKCS#11-like schema to store data in LDAP given
> >> DNS will need something similar, however the more we wandered into the
> >> discussion the more I got convinced the Vault is probably a better place
> >> to store this material than the LDAP tree itself at least for prvate
> >> keys.
> >
> > I only proposed something that would work for my needs (i.e. storing
> > certificates and associated trust policy) and would be ready for 4.0. Can you
> > say the same thing about the vault?
> I agree with Honza. I think that proposed LDAP schema is perfectly fits the 
> purpose *for public* information like certificates and public keys.

And I agree with you and Honza as well that the proposal is ok for
*public* information.

> >> For public key material only though I am not sure a pkcs#11 schema will
> >> necessarily be useful. It might, but we do not use it for public SSH
> >> keys. And we also already have schema for public User or Servers X509
> >> certs.
> >
> > Support for SSH public keys was implemented like 2 years ago, way before any
> > talk about the vault or PKCS#11 even started. As for certs, the proposed
> > schema works on top of RFC 4523, which is the cert schema you mention.
> >
> >>
> >> We need to define something for DNS public keys, but they are already
> >> published in DNS Records too if I am not wrong, would that be sufficient
> >> as a storage for the public part ? I am assuming the private keys are
> No, we need full PKCS#11 for OpenDNSSEC at least.

Well, you need a pkcs#11 library interface, the backing store could be anything,
but I do see the advantage of using a common schema so that SSSD can retrieve data
to present through that interface in a simplified and consistent way.

> Note that PKCS#11 in SSSD will give us generic mechanism for process/key 
> separation (it is practically the same thing GSS-Proxy, just general purpose). 
> This comes 'for free' if we implement PKCS#11 so please stop searching for 
> workarounds :-)

I am not looking for workarounds for the interface between SSSD and
consuming libraries. I am trying to evaluate what we could use this
schema for before jumping into it.

> >> stored in the Vault and they can be files in the format used by bind ?
> BIND files are very hackish and we need to do PKCS#11->BIND files conversion 
> anyway because OpenDNSSEC supports only PKCS#11 and nothing else.
> 
> I plan to use PKCS#11 directly from BIND so we can drop the format conversion 
> code and rely on pure PKCS#11 instead of bunch of hacks scripts.

Ok.

> > So the information would be scattered in different places, using different
> > formats and accessed using different protocols? I'm fine with that, but it is
> > way beyond my original idea, so please let whoever is in charge of the vault
> > implement the PKCS#11 module themselves.

Honza, clearly if something different is proposed work will be split
between those that need to implement it in various ways, this will
simply require to separate the pkcs#11 module into 2 parts, a 'feeder'
that implements the pkcs#11 interface and a pluggable 'gatherer' that
implements retrieval for specific stuff. No worries there.

> - IMHO public information should be stored in LDAP schema as proposed.
> - I agree that Vault is the right choice to store secrets.
> - I propose to combine these two: Store public information in LDAP and store 
> private keys in PKCS#8 blob as a secret in Vault.
> - This LDAP+Vault combo can be accessible over PKCS#11 interface.
> - Note that this will work even without vault if you want to store public 
> information only (like CA certs and NSS trust objects).

Works for me.

> The only problem is that we need to use REST API from SSSD. Plain LDAP is 
> already implemented in SSSD so it requires less code. I guess that we will 
> need something like libipavault library...

We'll need a helper process unless we can find a fully async library to
deal with the vault. Authentication to the vault over REST-like APIs
will also be an interesting problem ...

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York




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