[Pki-devel] [PATCH] 0026-5, 0044-3 Lightweight sub-CAs
Ade Lee
alee at redhat.com
Wed Aug 26 15:09:24 UTC 2015
Some more comments to clarify my concerns on the use of hierarchical
urls as the identifier for subcas.
This is the "usual" way (ie. for example OpenStack) REST interfaces are
defined:
POST /subcas -- creates a subca and returns the reference
/subcas/{uuid}
POST /subcas/ -- POST includes "parent_ref"=http://../subcas/{uuid}" ;
returns a subca that has the relevant parent
GET /subcas -- list all subcas
GET /subcas/{uuid} - get details on subca.
GET /subcas/{uuid}/subcas -- list subcas for subca {uuid}
An alternate formulation could also be:
POST /subcas/{uuid}/subcas
-- creates subca with subca {uuid} as parent.
I don't like this as much because its a little less standard. The
resulting resource would be /subcas/{uuid2} rather than
/subcas/{uuid}/subcas/{uuid2}
Now, I hate uuids. I mean whats not to love about "2a549393-0710-444b
-8aa5-84cf0f85ea79" ? It just rolls off the tongue.
Everyone hates uuids but thats actually an advantage, rather than a
weakness in that no one possibly would want to change the URL.
Handles on the other hand - are subject to all kinds of bike shedding.
Do I use something like "ca1", "ca2"? Thats no better than a UUID in
terms of semantic content. How about org references? "foo_it_dept",
"bar_domain"? Uh oh, what if I decide later I didn't like my handle?
What if there is an org rename? Or a reorg? Remember, certs can
potentially live a long time.
And what if I'm really perverse and use the handle "subcas" -- aargh!
now I've broken one of the possible paths above. Or I might end up
breaking a path we'll add in future.
No - the only way to keep this straight is to have the resource
identifier be something unique that no one will want to change -- like
/subcas/{uuid} - and have some kind of alias system for that subca that
can be changed at will.
That mapping could be kept in IPA or Barbican database for instance,
rather that in dogtag itself. We can also do what we did for secrets
and allow the user to define a "client nickname" as part of the subca
record. This is a field that can later be searched for or changed.
As for hierachical-ness, flatter is easier to understand and maintain.
Ade
On Wed, 2015-08-26 at 02:09 -0400, Ade Lee wrote:
> Some more thoughts.
>
> First off, there are things that should be included with the CAData
> for
> each subsystem.
>
> 1. CA signing cert (or more likely a reference to the ca cert)
> 2. pkcs7 chain (again this is something that could/should likely be a
> reference)
> 3. status - ie. enabled/disabled.
> 4. Description -- user defined description.
>
> For the motivation for (30 status, we do need to consider what we
> want
> do when someone wants to delete or decommission a subCA. If we want
> to
> keep the subCA record -- and we almost certainly need to -- we
> should
> probably add some kind of field to enable/disable.
>
> Second, we definitely need code to be able to issue a cert using the
> subcas from the REST interface. This will allow us to actually test
> that the subCA is working.
>
> Third, if we do stick with the current REST API, I think we should
> consider using something like:
>
> POST /subcas/ca1/ca2 {"id": "ca3"} to generate a subca /ca1/ca2/ca3
>
> Fourth, though, we need to consider carefully whether or not it makes
> sense to identify a subca through
> 1) an identifier that contains slashes
> 2) an identifier that is defined by the user instead of the server.
> We
> have currently no controls as to what names are chosen, and no clear
> rationale for what should be chosen.
>
> Much as I dislike uuids, there is a good reasons openstack uses them
> everywhere.
>
> We can discuss over IRC, but I can see many issues here.
>
> Ade
>
>
>
> On Tue, 2015-08-25 at 14:40 -0400, Ade Lee wrote:
> > Some initial comments and questions. Will have more after playing
> > with
> > it and testing. Looks pretty good so far.
> >
> > 1. what is
> > org.apache.tomcat.util.buf.UDecoder.ALLOW_ENCODED_SLASH=true
> > and why is it needed?
> >
> > 2. In CAService.java: issueX509Cert() - if ca is null, this throws
> > an
> > ECAException - which, if I understand the code correctly, ends up
> > being
> > some kind of BaseException. So, if someone requests a cert and
> > provides a bogus caref, it will be reported as a server error
> > instead
> > of a installation error?
> >
> >
> > 3. CertificateAuthority.java
> > -- subCAHier --> rename to subCAHierarchy.
> >
> > -- In the constructor, it would be useful to have example inputs in
> > the
> > method documentation so that we can see what data is expected to be
> > in
> > each of the fields. Its hard to review/understand/maintain
> > otherwise.
> >
> > -- you have extracted initCetDatabase() and initCRLDB(), also
> > extract
> > the replica repo initialization code into initReplicaRepo() or
> > similar.
> >
> > -- loadSubCAs - could use some description in method comments about
> > the
> > structure we expect to construct here. An example config would
> > help
> > understanding.
> >
> > -- createSubCA
> > -- returns ECAException() in many different cases ie.
> > if the CA exists, if the parent does not exist, if there is an
> > error in CA creation. This makes it difficult to separate out
> > the
> > things that are likely client request issues vs. server issues.
> > More likely, we want different exceptions that can be caught by
> > the
> > caller and handled appropriately.
> > -- what about uniqueness checks for the issuer DN?
> >
> >
> > 4. SubCAResource.java
> > -- path should be subcas ? not subca ..
> > -- acls needed of course
> >
> >
> > 5. CAEnrollProfile.java
> > --> could not reach CA -- that ends up being a ProfileException --
> > which maps to a server error? Is this a case where we need a
> > bad request exception instead?
> >
> > 6. subca.schema
> > -- why is it specified in a separate file? (and also in
> > schema.ldif)
> > -- the subca is uniquely defined by only one MAY attribute for
> > nickname (which is in printable string format)? Is that
> > sufficient
> > and should that be a required attribute? Do you need to store
> > the
> > issuerDN for uniqueness checks?
> >
> > 7. SubCAService.java
> > -- lets remove the commented out audit messages and functions
> > -- createSubCA()
> > -- should be some checks here on the data -- rather than
> > passing
> > through to the lower level. Bad data should return
> > BadRequestException, including for cases where we have
> > existing issuerDN or caRef.
> >
> > 8. SubCACreateCLI -- this code would be confusing:
> >
> > if (cmdArgs.length < positionalArgNames.length) {
> > System.err.println("Error: No "
> > + positionalArgNames[cmdArgs.length]
> > + " specified.");
> >
> > Just specify "Insufficient params .."
> >
> > 9. It would be good to have a DN check here on client side -- this
> > can be added in a separate patch.
> >
> > 10. Should users be able to define the nickname? I would say "yes"
> > because it might make it easier to notify services like custodia
> > for
> > instance to distribute keys.
> >
> > 11. Should we also have the option to define the token in which the
> > key is generated and stored? ( I think yes - in case for instance,
> > your HSM has limited keys). Where do the subCA keys get generated
> > by
> > default -- in the software or hardware token?
> >
> > 12. To help clarify this, please describe what would be created
> > if one were to add a new subCA using the CLI at reference caRef
> >
> > Specifically,
> > a) what database entry is created?
> > b) what is the nickname for the key/cert?
> > c) Where is the repo (ie. the suffix) for this ca's certs?
> > d) Exactly which resources belong to the subCA only?
> >
> > 8. SubCACreateCLI -- this code would be confusing:
> >
> > if (cmdArgs.length < positionalArgNames.length) {
> > System.err.println("Error: No "
> > + positionalArgNames[cmdArgs.length]
> > + " specified.");
> >
> > Just specify "Insufficient params .."
> >
> > 9. It would be good to have a DN check here on client side -- this
> > can
> > be added in a separate patch.
> >
> > 10. Should users be able to define the nickname? I would say "yes"
> > because it might make it easier to notify services like custodia
> > for
> > instance to distribute keys.
> >
> > 11. Should we also have the option to define the token in which the
> > key
> > is generated and stored? ( I think yes - in case for instance,
> > your
> > HSM has limited keys). Where do the subCA keys get generated by
> > default -- in the software or hardware token?
> >
> > 12. To help clarify this, please describe what would be created
> > if one were to add a new subCA using the CLI at reference caRef
> >
> > Specifically,
> > a) what database entry is created?
> > b) what is the nickname for the key/cert?
> > c) Where is the repo (ie. the suffix) for this ca's certs?
> > d) Exactly which resources belong to the subCA only?
> >
> > MISSING ITEMS:
> > These can be in a separate patch, but if so, we need tickets to
> > track
> > them:
> >
> > 1. acls
> > 2. auditing
> > 3. key parameters
> > 4. migration scripts (i.e. how to add db entries)
> > 5. tests - we need unit/functional tests to show the data that is
> > expected and to do basic error checking in the client. These
> > are
> > very important. Eventually, we would like tests to be a
> > required
> > part of any check-in.
> >
> > Ade
> >
> > On Mon, 2015-08-24 at 17:27 +1000, Fraser Tweedale wrote:
> > > Hi team,
> > >
> > > The latest sub-CAs patches are attached. It has been a while
> > > since
> > > the last patchset (that was posted here, anyway) and there have
> > > been
> > > some significant changes, outlined below. (The patchset version
> > > skipped a couple numbers due to versions distributed privately
> > > that
> > > I felt were not stable enough to warrant posting to pki-devel.)
> > >
> > > Major changes:
> > >
> > > - The Java client and CLI were extracted to a separate patch
> > > (0044).
> > > - An LDAP entry for each sub-CA is written to database.
> > > - Database searched and sub-CAs are initialised at startup
> > > - Key nickname is store in / read from LDAP entry
> > > - Sub-CA "list" API call, client method and CLI was added
> > > - More resources are shared between top-level CA and sub-CAs
> > > - Suprious task threads and LDAP connections hunted down :)
> > >
> > > Dependencies:
> > >
> > > - Patch 0026-5 probably depends on 0045[1] for a clean merge.
> > > - Patch 0044-3 depends on my patch 0046[2].
> > >
> > > [1]
> > > https://www.redhat.com/archives/pki-devel/2015-August/msg00072.ht
> > > ml
> > > [2]
> > > https://www.redhat.com/archives/pki-devel/2015-August/msg00073.ht
> > > ml
> > >
> > > Cheers,
> > > Fraser
> >
> > _______________________________________________
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> > Pki-devel at redhat.com
> > https://www.redhat.com/mailman/listinfo/pki-devel
>
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