[sfc] Alvaro Retana's No Objection on draft-ietf-sfc-nsh-integrity-06: (with COMMENT)

[Alvaro Retana via Datatracker <[e-mail]>]

Alvaro Retana has entered the following ballot position for
draft-ietf-sfc-nsh-integrity-06: No Objection

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COMMENT:
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(1) Given the required behavior specified in the Security Considerations
section...

   NSH data are exposed to several threats:

   o  A man-in-the-middle attacker modifying the NSH data.

   o  Attacker spoofing the NSH data.

   o  Attacker capturing and replaying the NSH data.

   o  Data carried in Context Headers revealing privacy-sensitive
      information to attackers.

   o  Attacker replacing the packet on which the NSH is imposed with a
      bogus packet.

   In an SFC-enabled domain where the above attacks are possible, (1)
   NSH data MUST be integrity-protected and replay-protected, and (2)
   privacy-sensitive NSH metadata MUST be encrypted for confidentiality
   preservation purposes.  The Base and Service Path headers are not
   encrypted.

Why doesn't this document formally update rfc8300?  Concerns that eventually
led to this solution have been expressed for several other documents, including
rfc8459 and rfc8979.

It looks like the WG didn't consider the question of Updating the base NSH
specification.  I believe that this document specifies a required update to
NSH, and would like the WG to consider formally Updating rfc8300.  [My search
of the archive didn't find any related discussion -- did I miss it?]

[Even though I consider this omission a serious oversight, I don't think this
issue raises to the level of a DISCUSS.]

(2) §3: I find the use of normative language to describe requirements (that are
met in this same document) not the best use of rfc2119 language because any
interoperability concerns would result from the specification itself and not
the requirements.

The use of rfc2119 keywords to describe requirements may result in confusion. 
For example, "The solution MAY provide integrity protection for the Base
Header." -- as described later, protecting the Base Header is optional, but the
solution *does* provide integrity protection for it.  IOW, the specification is
what is reflected in the requirement, but referring to the solution, not the
protection: providing integrity protection is not optional, using it is.  A
better working would be: "The solution must provide optional integrity
protection for the Base Header."