Subject: [secdir] secdir review of draft-ietf-slim-negotiating-human-language-22

From: Taylor Yu <[email-masked]>
Date: Thu, 11 Jan 2018 03:26:54 +0000

I have reviewed this document as part of the security directorate's
ongoing effort to review all IETF documents being processed by the
IESG.  These comments were written primarily for the benefit of the
security area directors.  Document editors and WG chairs should treat
these comments just like any other last call comments.

Summary: ready with minor issues

The security considerations section seems mostly reasonable.  The
emergency services use case vaguely bothered me in ways I couldn't quite
articulate at first, but I think Alissa Cooper's ballot comment about
denying emergency services by manipulating these attributes captures
most of the essence.

I would add for that these new language tags, integrity seems to be a
stronger requirement than confidentiality, at least in the emergency
calling use case.

Best regards,
-Taylor

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From: Randall Gellens <[email-masked]>
Date: Thu, 11 Jan 2018 07:10:43 -0800

>  stronger requirement than confidentiality, at least in the emergency

Hi Taylor,

Thanks for your review.  In response to Alissa's comments, I reworded 
the Security Considerations section to read:

    The Security Considerations of BCP 47 [RFC5646] apply here.  An
    attacker with the ability to modify signaling could prevent a call
    from succeeding by altering any of several crucial elements,
    including the 'hlang-send' or 'hlang-recv' values.  RFC 5069
    [RFC5069] discusses such threats.  Use of TLS or IPSec can protect
    against such threats.  Emergency calls are of particular concern; RFC
    6881 [RFC6881], which is specific to emergency calls, mandates use of
    TLS or IPSec (in ED-57/SP-30).

I think this also addresses your concern regarding integrity, as it 
specifically calls out "modification" as a principal threat.

--Randall

-- 
Randall Gellens
Opinions are personal;    facts are suspect;    I speak for myself only
-------------- Randomly selected tag: ---------------
Substitute "damn" every time you're inclined to write "very"; your
editor will delete it and the writing will be just as it should be.
              --William Allen White (famed Kansas newspaper editor)

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From: Taylor Yu <[email-masked]>
Date: Thu, 11 Jan 2018 20:14:28 +0000

> specifically calls out "modification" as a principal threat.

Hi Randall,

Thanks.  This new text seems reasonable.

-Taylor