Re: [sasl] I-D Action:draft-ietf-sasl-scram-08.txt

[Nicolas Williams <Nicolas.Williams at sun.com>]

On Thu, Oct 08, 2009 at 07:51:49AM +0200, Simon Josefsson wrote:
> Alexey Melnikov <alexey.melnikov at isode.com> writes:
> 
> >>   o  Normalize(str): Apply a Unicode normalization algorithm to a UTF-8
> >>      [RFC3629] encoded "str".  The resulting string is also in UTF-8.
> >>      Implementations SHOULD use the SASLPrep profile [RFC4013] of the
> >>      "stringprep" algorithm [RFC3454] as the normalization algorithm.
> >>----> Note that, for SCRAM, passwords are "stored strings", which means
> >>----> that unassigned codepoints in SCRAM passwords are prohibited (see
> >>----> RFC3454, section 7).
> >>  
> >>
> > Applied to my copy. I've reworded the text not to say "password", as
> > this is a generic definition of the Normalize function.
> 
> I don't think that works, unassigned codepoints should only be
> disallowed for passwords, not for usernames.  Elsewhere SCRAM says
> 
>          Before sending the username to the server, the client SHOULD
>          prepare the username using the "SASLPrep" profile [RFC4013] of
>          the "stringprep" algorithm [RFC3454] treating it as a query
>          string (i.e., unassigned Unicode code points are allowed).

That's fine with me.  It's important that the server not re-encode the
client's first message when verifying the ClientSignature.

Nico
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