Subject: [nfsv4] supported Kerberos encryption types

From: Rick Macklem <[email-masked]>
Date: Tue, 16 Oct 2018 03:51:36 +0000

First off, I need to put a disclaimer here, which is basically that I know almost
nothing about Kerberos.

What I have been wondering for some time is what encryption types for
RPCSEC_GSS/krb5 are being supported by various implementations for NFSv4?
- For FreeBSD, I think the current answer is DES, DES3, AES128, AES256, Arcfour
  and Arcfour_56, but I may have misread the code.

Long ago I recall everyone using DES during interoperability testing, but I assume
implementations have moved beyond that?
And, do others know how an encryption type is chosen by various Kerberos
implementations? (Is it based on the encryption type used for the tickets that
is usually specified by a configuration file like /etc/krb5.conf or...)

Thanks for any info, rick

---

From: Chuck Lever <[email-masked]>
Date: Tue, 16 Oct 2018 09:52:35 -0400

Hi Rick-

I know a few details, but anyone can correct me if I'm mistaken.

> On Oct 15, 2018, at 11:51 PM, Rick Macklem <[email-masked]> wrote:
> 

In Linux, Kerberos can be used for any version of NFS.

>  and Arcfour_56, but I may have misread the code.

Linux kernel currently supports all of those but Arcfour_56, but I'm planning
to remove support for everything but the AES enctypes because the others are
known to be insecure and/or are no longer widely deployed. We don't have any
convenient method for testing our implementations.

> implementations have moved beyond that?

At recent testing events we've been using an IPA KDC which by default allows
only the AES enctypes.

> _______________________________________________
> nfsv4 mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/nfsv4

--
Chuck Lever
[email-masked]

---

From: Benjamin Kaduk <[email-masked]>
Date: Tue, 16 Oct 2018 13:06:37 -0500

> convenient method for testing our implementations.

Indeed, RFC 8429 (draft-ietf-curdle-des-des-des-die-die-die) is in AUTH48
and will "officially" deprecate DES3 and Arcfour in Kerberos; RFC 6649
already did that for DES and Arcfour_56.

-Ben

---

From: Chuck Lever <[email-masked]>
Date: Tue, 16 Oct 2018 14:13:13 -0400

> On Oct 16, 2018, at 2:06 PM, Benjamin Kaduk <[email-masked]> wrote:
> 

Good to know. I will note that in my commit message.

--
Chuck Lever
[email-masked]