Re: Further IESG feedback on draft-crispin-imapv-17.txt

["Jeffrey I. Schiller" <[e-mail]>]

I can live with Mark's proposed paragraph.

			-Jeff

Mark Crispin wrote:
> I share Larry's concern.
> 
> We agree with the IESG that this requirement should be "mandatory to
> implement".  What makes it untenable for us is the implication that an
> implementation which does not enforce "mandatory to deploy" is non-compliant.
> 
> Server implementors are not in a position to enforce "mandatory to deploy",
> and there are legitimate reasons why a site may choose to deploy unprotected
> plaintext authentication.
> 
> Note the following text in RFC 2595:
>    [...]  The PLAIN SASL mechanism
>    MUST NOT be advertised or used unless a strong encryption layer (such
>    as the provided by TLS) is active or backwards compatibility dictates
>    otherwise.
> 
> IESG approved this as standards-track for a new protocol (the PLAIN SASL
> mechanism) which did not have any standards-track legacy to consider.  IMAP,
> on the other hand, has a standards-track legacy and furthermore a production
> installed base dating from 1985.
> 
> This is, to put it mildly, inconsistent.
> 
> Is the following compromise be acceptable to the IESG?
> 
> Note: a server implementation MUST implement a configuration in which
>       it does NOT permit any plaintext password mechanisms unless the
>       STARTTLS command described in [IMAP-TLS] has been negotiated or
>       some other mechanism that protects the session from password
>       snooping has been provided.  Server sites SHOULD NOT use any
>       configuration which permits a plaintext password mechanism without
>       a protection mechanism against password snooping.  Client and
>       server implementations SHOULD implement additional SASL mechanisms
>       which do not use plaintext passwords, such the GSSAPI mechanism
>       described in [SASL] and/or the [DIGEST-MD5] mechanism.
> 
> This clearly puts the vendor off the hook if it has implemented the correct
> mode, even if the site chooses to use the incorrect mode.
>