Re: [regext] Benjamin Kaduk's Discuss on draft-ietf-regext-login-security-07: (with DISCUSS and COMMENT)

["Gould, James" <[e-mail]>]

Barry & Ben,

Thanks for the detailed discussion.  I will change the "recommended" to the normative "RECOMMENDED" and change the PRECIS sentence to match Ben's proposal.  The end result will be:

It is RECOMMENDED that the plain text password in the <loginSec:pw> and <loginSec:newPw> elements use printable ASCII characters #x20 (space) - #x7E (~), with high entropy, such as 128 bits. If non-ASCII characters are supported with the plain text password, then use a standard for passwords with international characters; the OpaqueString PRECIS profile in [RFC8265] is recommended in the absence of other considerations.

I'll include this change in the posting of draft-ietf-regext-login-security-09.

Thanks,

-- 
 
JG



James Gould
Distinguished Engineer
[e-mail] <applewebdata://13890C55-AAE8-4BF3-A6CE-B4BA42740803/[e-mail]>

703-948-3271
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Reston, VA 20190

Verisign.com <http://verisigninc.com/>

On 2/22/20, 6:15 PM, "Barry Leiba" <[e-mail]> wrote:

    Thanks, Ben; this helps a lot.
    
    Jim, are you good with Ben's suggestion or a variation of that?  It's
    just a small update to what you have, and makes it clearer that if you
    need I18N, PRECIS is the weay to do it.
    
    Barry
    
    On Fri, Feb 21, 2020 at 10:08 PM Benjamin Kaduk <[e-mail]> wrote:
    >
    > Hi Barry,
    >
    > On Sat, Feb 15, 2020 at 12:12:29AM -0500, Barry Leiba wrote:
    > > Hi, all...
    > >
    > > I'm sorry if I'm not completely clear about where the discussion is,
    > > but what Jim's mail system does to the quoting is horrendous (as is
    > > the case with most HTML-based mail systems), and I can't easily follow
    > > the thread.
    >
    > I sympathize; I find that with some regularity I end up saving the
    > text/html component to a file and opening it in a browser in order to have
    > a chance of figuring out what's going on.
    >
    > > So I'm just picking up this recent bit from Ben:
    > >
    > > > I think it would probably be helpful for the responsible AD to chime in; my
    > > > understanding is still that the PRECIS profiles are to be used as part of a
    > > > protocol as opposed to part of a deployment, and that allowing for
    > > > different rules to be used in different sites is risky.  I understand that
    > > > there's the extra context here of the potential for preexisting deployments
    > > > that started using non-ASCII passwords in the absence of any guidance from
    > > > the IETF on how to do so, and we have to consider whether what we do will
    > > > break them, and so hearing from someone versed in the matter who has
    > > > thought about this particular case would help assuage my concerns.  One
    > > > possible route (given that, as I understand it, a lot of EPP deployments
    > > > involve exchange of configuration and deployment information between peers
    > > > out of band) would be to say that the PRECIS profile is used as a default
    > > > in the absence of other configuration knowledge for a given deployment,
    > > > though I acknowledge that this is not without flaws.
    > >
    > > I had discussed the PRECIS issue with Jim, which is what resulted in this text:
    > >
    > >    It is recommended that the plain text password in the <loginSec:pw>
    > >    and <loginSec:newPw> elements use printable ASCII characters #x20
    > >    (space) - #x7E (~), with high entropy, such as 128 bits.  If non-
    > >    ASCII characters are supported with the plain text password, then use
    > >    a standard for passwords with international characters, such as the
    > >    OpaqueString PRECIS profile in [RFC8265].
    > >
    > > I think that's adequate, given that (1) we really are expecting that
    > > almost all passwords out there are ASCII, and we're recommending
    > > keeping it that way, (2) we need to allow, but discourage, non-ASCII
    > > UTF-8 passwords for the (expectedly rare) cases where they might be
    > > used, and (3) these are stored passwords that are passed around,
    > > rather than passwords entered by users and subject to issues created
    > > by different input mechanisms and effects on eyeballs.
    > >
    > > I can see that we might want to change "recommended" to "RECOMMENDED",
    > > and I don't object to that (Jim?).  Beyond that, I'm not sure where
    > > you're going with "PRECIS profiles are to be used as part of a
    > > protocol as opposed to part of a deployment."  It's really both,
    > > depending upon the situation.  In this case, it's saying that if your
    > > server supports non-ASCII passwords, you'd better use the OpaqueString
    > > profile to handle them.  If your server doesn't (it supports only
    >
    > I'm much happier with your prose description here than the snippet quoted
    > from the document -- what's in the document now seems to be weaker than
    > what you say ("pick a standard; PRECIS is a standard" vs "you should use
    > PRECIS, though here's an out if you can't for some reason").
    >
    > My primary concern here is that the client and server need to know to use
    > the same standard (whatever it is).  Making this RFC say flatly "use
    > PRECIS" is IMO the easiest way to do that, though given how much other
    > stuff in EPP has to be set by out-of-band configuration I won't raise a
    > fuss if this ends up being another one.  If it does need to be known out of
    > band, though, my preference is always for that need to be stated in the
    > RFC.
    >
    > > ASCII passwords), we're good.  From a PRECIS point of view, I don't
    > > see more that needs to be done with this.
    > >
    > > I think a large part of the point of the text that Jim added is an
    > > acknowledgement that in the common case of ASCII-only passwords, we
    > > don't have to worry about normalization/canonicalization of password
    > > strings at all, and just doing straight byte-string comparisons works.
    > > And the OpaqueString profile is there for cases where it's needed.
    > >
    > > Now, it's certainly true that if a server *supports* non-ASCII
    > > passwords, then *all* password processing on that server has to use
    > > the OpaqueString profile, even if there are not any actual non-ASCII
    > > passwords present... just in case one might show up.  And I think the
    > > text does say that.
    >
    > (repeating myself, but I think the text says "all password processing on
    > that server has to use the chosen standard for non-ASCII passwords" [which
    > is not necessarily the OpaqueString PRECIS profile])
    >
    > > Is there something in this discussion that I'm missing that I need to
    > > address?  Is there specific text you might suggest?  Are there other
    > > issues beyond this one that are still open?  How close are we to
    > > resolving this?
    >
    > I think just adding the extra background and your sense of what the text is
    > trying to convey has been a big help.  I would suggest rewording to:
    >
    >   [...].  If non-
    >   ASCII characters are supported with the plain text password, then use
    >   a standard for passwords with international characters; the
    >   OpaqueString PRECIS profile in [RFC8265] is recommended in the absence of
    >   other considerations.
    >
    > Your explanation suffices such that I will not require this change to clear
    > my Discuss, though.
    >
    > -Ben