I am now getting more familiar with PKCS#11 and did check which objects are handled by softhsm and I think the best way would be a direct mapping of a subset of the pkcs#11 objectclasses and attributes to LDAP. In my understanding we would only need the objectclasses of storage objects: certificate, {private|public|secret}key, evtl data. The attributes would then be the attributes required by these objectclassses. And here I am having a bit difficulties, eg in the spec: ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-11/v2-30/pkcs-11v2-30b-d6.pdf in the example (11.7) for adding a publicKey the attributes CKA_MODULUS and CKA_PUBLIC_EXPONENT are used, but these are not listed in the tables in 10.7 as "Common Key Attributes", so how do I know which are the required and allowed attributes for these objectclasses ? I will start to write a draft for the schema definitions we can discuss, but any input is welcome.


On 02/18/2014 03:17 PM, Jan Cholasta wrote:

On 18.2.2014 14:02, Ludwig Krispenz wrote:

yesterday jan asked me about the status of the schema and if it would be
ready for certificate storage an dthat puzzled me a bit and showed that
I still do not really understand what you want to store in LDAP.
Two me there are two very different approaches.

1] LDAP as store for high level objects like certs and keys
For certs and related stuff there is rfc4523 and the schema for ldif
exists. For keys we would decide if the key is stored in PKCS#8 format
or as bind keypairs and define a key attribute and that's it. we could
export keys with softhsm, (eventually convert them) and add to ldap, in
the long term solution the PKCS#11 replacemnt would need to manage these
high level objects

I think RFC 4523 is not the right schema in this case, as it is suited for PKIs rather than generic cryptographic data storage. For example, RFC 4523 distinguishes between CA and end entity certificates, but in PKCS#11 there are just certificates without any semantics attached to them.

2] low level replacement for eg the sqlite3 database in softhsm.
That's what I sometimes get the impression what is wanted. SoftHsm has
one component Softdatabase with an API, which more or less passes sets
of attributes (attributes defined by PKCS#11) and then stores it as
records in sql where each record has a keytype and opaque blob of data.
If that is what is wanted the decision would be how fingrained the pkcs
objects/attribute types would have to be mapped to ldap: one ldap
attribute for each possible attribute type ?

One-to-one mapping of attributes from PKCS#11 to LDAP would be the most straightforward way of doing this, but I think we can do some optimization for our needs. For example, like you said above, we can use a single attribute containing PKCS#8 encoded private key rather than using one attribute per private key component.

I don't think we need an LDAP attribute for every possible PKCS#11 attribute, ATM it would be sufficient to have just these attributes necessary to represent private key, public key and certificate objects.

So, I would say it should be something between high-level and low-level.


Freeipa-devel mailing list

Reply via email to