On 07/25/2016 08:12 AM, Alexander Bokovoy wrote:
On Mon, 25 Jul 2016, Jan Cholasta wrote:
This is turning out to be a common (and, I think, reasonable)
reaction
to the proposal. It is rather complex, and I worry that it will be
difficult to configure. On the other hand, there is some hidden
complexity to enabling a simpler config format, as well. One of the
goals of the project as it was presented to me was to allow the
creation
of profiles that add certificate extensions *that FreeIPA doesn't yet
know about*. With the current proposal, one only has to add a rule
generating text that the helper will understand.
... which will be possible only as long as the helper understands the
extension. Which it might not, thus the current proposal works only
for *some* extensions that FreeIPA doesn't yet support.
We can go ad infinitum here but with any helper implementation, be it
python-cryptography or anything else, you will need to have a support
there as well.
My point was that the current proposal is not any better than my
proposal in this regard, as neither of them allows one to use an
arbitrary extension.
That's true. One of arguments for supporting openssl format was to allow
people to generate CSRs themselves later. E.g. it would be a stepping
stone to some automation around certificates to those who need it.
Turning everything into python-cryptography has less benefit in this
context.
The idea with unknown extensions was to allow mapping
their acceptance to a specific relationship between IPA objects
(optionally) and an input from the CSR. A simplest example would be an
identity rule that would copy an ASN.1 encoded content from the CSR to
the certificate.
That's on the mapping side, not on the CSR generation side, but it
would
go similarly for the CSR if you would be able to enter unknown but
otherwise correct ASN.1 stream. There is no difference at which helper
type we are talking about because all of them support inserting ASN.1
content.
Along similar lines, on the CSR generation side, certutil has an
--extGeneric flag, and openssl also has an "ARBITRARY EXTENSIONS"
feature described in x509v3_config(5). I'm guessing that generating
those configs automatically would be a bit beyond the current feature
set of jinja2, but when we allow the requester to specify contents for
some of the data fields it should be possible to build ok automation
around that.
With your suggestion,
if there's a mapping between "san_directoryname" and the
corresponding
API calls or configuration lines, we need some way for users to
augment
that mapping without changing the code. If there's no mapping, and
it's
just done with text processing, we need enough in the config
format to
be able to generate fairly complex structures:
builder = builder.subject_name(x509.Name(u'CN=user,O=EXAMPLE.COM'))
builder =
builder.add_extension(x509.SubjectAlternativeName([x509.RFC822Name(u'u...@example.com'),
x509.DirectoryName(x509.Name(u'CN=user,O=EXAMPLE.COM'))]), False)
and we need to do it without it being equivalent to calling eval() on
the config attributes. I'm not sure how to achieve this (is it
safe to
call getattr(x509, extensiontype)(value) where extensiontype and
value
are user-specified?) and it definitely would have to be tied to a
particular library/tool.
As I pointed out above, this needs to be figured out for the generic
case for both the current proposal and my suggestion.
OTOH, I think we could use GSER encoding of the extension value:
{ rfc822Name:"u...@example.com",
directoryName:rdnSequence:"CN=user,O=EXAMPLE.COM" }
GSER is not really used widely and does not have standardized encoding
rules beyond its own definition. If you want to allow transformation
rules in GSER that mention existing content in IPA objects, you would
need to deal with templating anyway. At this point it becomes
irrelevant
what you are templating, though.
True, but the goal here is not to avoid templating, but rather to
avoid implementation-specific bits on the server, and GSER is the
only thing that is textual, implementation-neutral and, as a bonus,
standardized.
If we move these bits to the client, the only thing server will need to
deal with is CSR. The client then would definitely need to have ability
to provide alternative CSR sources (e.g. openssl text format) to aid
API users that don't utilize IPA tools directly. At this point GSER use
is irrelevant either.
The GSER format is new to me, but I don't see any particular reason the
existing design would not be able to produce this format. But: is there
an existing library that allows creating a CSR from a GSER description?
If our goal is to provide an easy way to create certificates according
to a particular profile, and the CSR is still our main way to provide
that data to the IPA cert-request feature, we need to be able to build
that CSR. If we have a client that accepts GSER and has at least the CSR
generation features we need, then maybe we don't need support for
generating the other formats anymore.
--
Manage your subscription for the Freeipa-devel mailing list:
https://www.redhat.com/mailman/listinfo/freeipa-devel
Contribute to FreeIPA: http://www.freeipa.org/page/Contribute/Code
