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

[Barry Leiba <[e-mail]>]

Great; thanks, Jim.  Ben, are you OK with this now?

Barry

On Mon, Feb 24, 2020 at 5:28 AM Gould, James <[e-mail]> wrote:
>
> 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
> 12061 Bluemont Way
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>
> 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
>
>