Subject: [Bier] Mirja Kühlewind's No Objection on draft-ietf-bier-isis-extensions-07: (with COMMENT)

From: Mirja Kühlewind <[email-masked]>
Date: Mon, 19 Feb 2018 06:50:06 -0800

Mirja Kühlewind has entered the following ballot position for
draft-ietf-bier-isis-extensions-07: No Objection

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COMMENT:
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1) Minor comment: The shepherd write-up says wrongly that this docoment is
experimental. Assume that was changed at some point during the process.

2) There further seem to be unaddressed comments in the write-up...

3) Please use rfc8174 boilerplate.

4) The IANA section should contain the exact name and URL of the registry that
the new sub-TLV value should be addd to.

5) The document should maybe provide further guidance on how the stated goal in
the security  considerations section could be achieved.

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From: Alia Atlas <[email-masked]>
Date: Mon, 19 Feb 2018 09:54:56 -0500

On the status, we're also starting the BIER recharter this telechat - to
move the work from
Experimental to Standards Track. The WG has wanted the work to be Standards
Track from the beginning.

Regards,
Alia

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From: "Les Ginsberg (ginsberg)" <[email-masked]>
Date: Mon, 19 Feb 2018 19:00:50 +0000

Mirja -

Thanx for the review - inline.

> -----Original Message-----
> From: Mirja Kühlewind [mailto:[email-masked]]
> Sent: Monday, February 19, 2018 6:50 AM
> To: The IESG <[email-masked]>
> Cc: [email-masked]; Hooman Bidgoli
> <[email-masked]>; [email-masked];
> [email-masked]; [email-masked]
> Subject: Mirja Kühlewind's No Objection on draft-ietf-bier-isis-extensions-
> 07: (with COMMENT)
> 
> When responding, please keep the subject line intact and reply to all email
> addresses included in the To and CC lines. (Feel free to cut this introductory
> paragraph, however.)
> 
> 
> 1) Minor comment: The shepherd write-up says wrongly that this docoment
> is experimental. Assume that was changed at some point during the process.
> 
[Les:] I believe Alia has already replied to this.

> 2) There further seem to be unaddressed comments in the write-up...
[Les:] All comments have been addressed in V7 of the draft - or we have explained why we do not feel a text change is needed.

> 3) Please use rfc8174 boilerplate.
[Les:] Ack - will incorporate that in next revision.
 
> 4) The IANA section should contain the exact name and URL of the registry
> that the new sub-TLV value should be addd to.
> 
[Les:] Ack - will cleanup the named reference.

> 5) The document should maybe provide further guidance on how the stated
> goal in the security  considerations section could be achieved.
> 

[Les:] The Security section currently states:

" Implementations must assure that malformed TLV and Sub-TLV
   permutations do not result in errors which cause hard protocol
   failures."

In fact, there is nothing unique about the BIER advertisements in this regard. Malformed TLVs of any kind can cause protocol failures if an implementation does not guard against this. This is a base protocol issue. So this text is really inappropriate.
Here is new proposed text:

" Security concerns for IS-IS are addressed in [RFC5304] and [RFC5310].

   Advertisement of the additional information defined in this document
   introduces no new security concerns."

   Les

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From: "Mirja Kuehlewind (IETF)" <[email-masked]>
Date: Mon, 19 Feb 2018 20:14:11 +0100

Hi Les,

see inline.

> Am 19.02.2018 um 20:00 schrieb Les Ginsberg (ginsberg) <[email-masked]>:
> 
> Mirja -
> 

Yes, that’s fine.
> [Les:] All comments have been addressed in V7 of the draft - or we have explained why we do not feel a text change is needed.

Then the write-up should be updated I guess
> [Les:] Ack - will incorporate that in next revision.

Thx.
> [Les:] Ack - will cleanup the named reference.
Thx.

>   introduces no new security concerns.“

Makes more sense to me.

Mirja

---

From: Tony Przygienda <[email-masked]>
Date: Mon, 19 Feb 2018 11:39:06 -0800

> > In fact, there is nothing unique about the BIER advertisements in this
> regard. Malformed TLVs of any kind can cause protocol failures if an
> implementation does not guard against this. This is a base protocol issue.
> So this text is really inappropriate.
I concur with Les here. BIER does not do anything new or magical to the
TLVs or ISIS encoding in general.

Now, whether the issue of TLV security in ISIS (or even wider scope) needs
addressing in some form is outside the scope of this thread, but IMO it
merits attention. Hand-written non-orthogonal parsers and encoders which we
needed on many IETF technologies so far due to performance constraints are
a very major source of defects/vulnerabilities and maybe something needs
said/done there.  Good news that albeit certain technologies will still
need max-perf-hand-written ser/deser in IP, many protocols we are using
moved already to computation substrate which offer enough performance to
allow modelling as practical implementation technique and IMO this is a
chance for IETF ...

--- tony