On 19.4.2017 17.17, Philip Brusten wrote:
Assume you have a PKI like:
- intermediate CA 1
- issuing CA 1
- intermediate CA 2
- issuing CA 2
If you only want to trust endpoint certificates for EAP-TLS issued by
"issuing CA 2", would it be sufficient to *only* trust "issuing CA 2" in
Possibly yes. I think that in X.509 the trusted CAs, or trust anchors as
they are called, do not need to have subject and issuer that is equal.
This is what the current practice is with root CA certificates (you need
to put something in issuer so own name is used).
In other words, you could try using any CA certificate as a trust anchor
by configuring it as trusted. What is unsure, the "possibly" part,
refers to the question if the software can be configured to do so.
What comes to Radiator, the configuration parameters affect what is
passed to Net::SSLeay which then talks directly to OpenSSL/LibreSSL/etc.
This means the TLS library manual could also be helpful to see what and
how to configure. There's also the question of different library
versions having different behaviour.
In short: you could test and see if it works.
In addition to this, you could consider EAPTLS_CertificateVerifyHook to
see that the client certifcate's issuer is "issuing CA 2". This could
provide a good belt + suspenders configuration even if trusting "issuing
CA 2" would work by itself.
Or is it required to trust the entire chain: "root CA" + "intermediate
CA 2" + "issuing CA 2"?
If you do the latter and a supplicant device has a certificate issued by
"issuing CA 1" and sends its entire certificate chain up to the root CA
during the handshake, will it be validated as well?
I'd say there's potential for this to happen. In this case you could use
the hook I mentioned above to see that everything else except of
certificates issued by "issuing CA 2" get grounded and rejected.
not entirely clear on that.
I think we'd need to say that TLS library manual would be the canonical
source of information for these options.
Please let the list know how it goes!
Heikki Vatiainen <h...@open.com.au>
Radiator: the most portable, flexible and configurable RADIUS server
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