[6tisch] Benjamin Kaduk's No Objection on draft-ietf-6tisch-enrollment-enhanced-beacon-13: (with COMMENT)

Benjamin Kaduk via Datatracker <noreply@ietf.org> Tue, 18 February 2020 23:12 UTC

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Subject: [6tisch] Benjamin Kaduk's No Objection on draft-ietf-6tisch-enrollment-enhanced-beacon-13: (with COMMENT)
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Benjamin Kaduk has entered the following ballot position for
draft-ietf-6tisch-enrollment-enhanced-beacon-13: No Objection

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COMMENT:
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Where is PAN/PANID defined?  I did not find it in RFC 6550, 8180, or
draft-ietf-6tisch-architecture, nor in the RFC Editor's list
(https://www.rfc-editor.org/materials/abbrev.expansion.txt).

Thank you for discussing the security considerations of each field
throughout!

Section 1.3

   Although However, even in this case, a unicast RS may be transmitted
   in response[RFC6775] reduces the amount of multicast necessary to do
   address resolution via Neighbor Solicitation (NS) messages, it still
   requires multicast of either RAs or RS.  This is an expensive

nits: two capitalized words in a row, also some further rewording is
needed (and maybe s/unicast RS/unicast RA/?).

Section 2

We should probably say something about the 'res' bits being reserved,
set to zero, and ignored by recipients.

      In most cases, every node sending a beacon will set this flag, and
      in a typical mesh, this will be every single node.  When this bit
      is not set, it indicates that this node may be under provisioned,
      or may have no additional slots for additional nodes.  This could
      make this node more interesting to an attacker.

nit: this phrasing suggests that the list is an exhaustive list of
reasons why the flag could be unset; I'd suggest "it might indicate"
instead.

      This value MUST be ignored by pledges, it is to help enrolled
      devices only to compare different connection points.

nit: comma splice.  Maybe also reword to "It is only to help enrolled
devices to compare different connection points"?

      This field communicates an Interface ID bits that should be used
      for this nodes' layer-3 address, if it should not be derived from

nit: singular/plural mistmatch in "an Interface ID bits"
nit: s/nodes'/node's/

      the layer-2 address.  Communication with the Join Proxy occurs in
      the clear, this field avoids the need for an additional service
      discovery process for the case where the L3 address is not derived
      from the L2 address.  An attacker will see both L2 and L3

nit: comma splice.  I'd also hyphenate "service-discovery".

      once.  That is just a suggestion for a default algorithm: it may
      be set in any convenience way that results in a non-identifing
      value.  In some LLNs where multiple PANIDs may lead to the same

nits: I suggest "Per [RFC6550], that is just a suggestion",
s/convenience/convenient/, and s/identifing/identifying/ (though what
exactly it is that is not being identified might be worth clarifying,
too).

      management device (the JRC), then a common value that is the same
      across all PANs MUST be configured so that pledges that attempt to

nit: I think "all the PANs" is more appropriate, since we only care
about the ones that lead to the same JRC (and there may be other PANIDs
in play).

      enroll do not waste time attempting multiple times with the same
      network that has multiple attachment points.

nit: I'd consider expanding (again) what is being attempted.

      If the network ID is derived as suggested, then it will an opaque,

nit: s/will/will be/

      seemingly random value, and will reveal nothing in of itself.  An

I suggest "will not directly reveal any information about the network".

Section 3

   The sensitivity of each field is describe within the description of
   each field.

nit: s/describe/described/

   visible.  Encrypting the schedule does not prevent an attacker from
   jamming, but rather increases the energy cost of doing that jamming.

Perhaps also the side effects/collateral damage of the jamming.