From: Victor Duchovni (Victor.DuchovniMorganStanley.com)
Date: Wed Sep 19 2007 - 11:18:21 CDT

• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

On Wed, Sep 19, 2007 at 12:11:07PM -0400, Wietse Venema wrote:

> > I take that as a very qualified yes. The code in question would I think be
> > confined to the mime_state engine, which given a new flag (optionally, but
> > by default enabled in cleanup) would look for "true" 8bit octets in the
> > bodies of MIME entities with a CTE of "8bit". If no such octets are found,
> > the message-level encoding is 7bit, even if the sender (via BODY=8BITMIME
> > in MAIL FROM:) or CTE headers in one or more non-composite MIME parts
> > signaled possible 8bit content.
>
> I forgot to mention performance - if a workaround impacts performance,
> then it should not be enabled by default.

Well, all characters of the input are already compared with <CR> and
<LF> to detect line endings. It seems unlikely that checking the high
bit would impose a noticeable additional cost.

> > This is somewhat comparable in cost to a regexp check on each line of
> > body content, except that base64 and QP content is always uninspected
> > (cheaper) while 8bit content is inspected in its entirety (not just the
> > first $body_checks_size_limit octets, more expensive).
>
> Postfix by default disables features such as header/body_checks,
> 8strict_8bitmime, message_strip_characters, message_reject_characters
> and so on because they increase the cost of handling mail for
> everyone.

As the main benefit of avoiding unnecessary 8-7 conversion is for signed
email, this feature can be disabled by default, with those doing signing
encouraged to enable it, and thus avoid unnecessary conversions or possible
signature failures downstream.

I am not overly concerned about the default behaviour just yet, what is
your take on feasibility or wisdom?

--
        Viktor.

Disclaimer: off-list followups get on-list replies or get ignored.
Please do not ignore the "Reply-To" header.

To unsubscribe from the postfix-users list, visit
http://www.postfix.org/lists.html or click the link below:
<mailto:majordomopostfix.org?body=unsubscribe%20postfix-users>

If my response solves your problem, the best way to thank me is to not
send an "it worked, thanks" follow-up. If you must respond, please put
"It worked, thanks" in the "Subject" so I can delete these quickly.

• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]