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From:   Olga Kornievskaia <aglo@umich.edu>
Date:   Thu, 5 Nov 2020 14:47:41 -0500
Message-ID: <CAN-5tyFAc0R=D0OL2WHkKacTMW0JxKmLoqv2A2Et2gg5G6gjtQ@mail.gmail.com>
Subject: question about labeled NFS+rfc7569+selinux
To:     NFSv4 <nfsv4@ietf.org>
Cc:     linux-nfs <linux-nfs@vger.kernel.org>, earsh@netapp.com
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Hi folks,

I would like to know if somebody can comment on the following
regarding labeled NFS.

RFC 7569 talks about Label formats and specifically lists that "0" is
a reserved value.

Using labeled NFS with SElinux and looking at labels (in wireshark),
the selinux sends sends/sets label format as 0 (ie. this is a reserved
value according to the spec)

So we have labelformat_spec4 set to 0 where the spec says this field
"The LFS and the Security Label Format Selection Registry are
described in detail in [RFC7569]". It's unlikely that  "0" reserved
for Selinux and not explicitly specified there?

0 seems to be a good choice for using as a default label which the
RFC7862 vaguely talks about (though says nothing about the format for
a default label).

I'm not aware if Selinux is supposed to follow a spec and therefore I
don't think it is obligated to follow the rules of RFC 7569. Anybody
can comment how labeled NFS label format and SElinux label format
choice are supposed to co-exist?

Thank you.