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Re: Last Call: <draft-hardie-privsec-metadata-insertion-05.txt> (Design considerations for Metadata Insertion) to Informational RFC

2017-02-22 16:09:43
Hi Mohamed,

Thanks for your review.  I've uploaded a draft -06 with updates from your
and other reviews.  Some notes in-line.

On Tue, Jan 31, 2017 at 1:49 AM, 
<mohamed(_dot_)boucadair(_at_)orange(_dot_)com> wrote:

Dear Ted,

Please find below my general review of the document and also my detailed
comments.

* Overall:
- I don't think the document is ready to be published as it is. It does
not discuss the usability and implications of the advice. Further, it may
be interpreted that a client/end system/user can always by itself populate
data that is supplied by on-path nodes (in current deployments). That's
assumption is not true for some protocols.
- The purpose of publishing this advice is not clear. For example, how
this advice will be implemented in practice? What is its scope?
- I would personally prefer an updated version of RFC7258 with more strict
language on the privacy-related considerations. This is more actionable
with concrete effects in documents that will required to include a
discussion on privacy related matters.

Detailed comments are provided below:

* The abstract says the following:

   The IAB has published [RFC7624] in response to several revelations of
   pervasive attack on Internet communications.  This document considers
   the implications of protocol designs which associate metadata with
   encrypted flows.  In particular, it asserts that designs which do so
   by explicit actions of the end system are preferable to designs in
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   which middleboxes insert them.

I suggest you explicit what is meant by "the end system".


I have updated this to clarify that this is the host/end system not the
user.


If you mean the owner/user, then the text should say so. If you mean a
client software instance, then bugs/inappropriate default values may lead
to (privacy leak) surprises too. It was reported in the past that some
browsers inject the MSISDN too.

* Introduction: "To ensure that the Internet can be trusted by users"

Rather « To minimize the risk of Internet-originated attacks targeted at
users ».


I've adopted this language.


It's reasonable to claim the Internet can be trusted by users; see how the
usage of social networks has become severely twisted for example


I've also considered your point that an updated version of RFC7258 might be
a better outlet for advice like this. We did consider several approaches,
including incorporating the text in an update to  RFC 3552 or as part of a
document describing the full set of companion mitigations to the threats in
RFC 7624 (draft-iab-privsec-confidentiality-mitigations would be one
approach).  Those are all valid approaches, but it seemed that short,
easily read documents tackling a single point might be easier to produce
and consume.

Thanks again for your review,

Ted Hardie