Re: [exim] Spam using a space to separate message body and h…

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Autor: Philip Hazel
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A: Exim User's Mailing List
Assumpte: Re: [exim] Spam using a space to separate message body and header...
On Sun, 4 Sep 2005, Ted Cooper wrote:

As you have all been discovering, this area is a swamp with tarpits and
quicksands in it. Probably alligators as well. Remember also that RFC
2822 is still very "new", and that these definitions were less specific
in RFC 822, which much software that is still in use was written to
support.

> I think this in reference to creating a message in the first place. You MUST
> NOT create a folded header with only white space because when you unfold them
> and the CRLF all become "invisible" all you get is the one header line with a
> few white spaces in it.


Following a discussion some years ago, I think on the 822 mailing list,
and probably before RFC 2822 was published, I added some extra logic to
Exim according to this comment from the source:

    /* It is perfectly legal to have an empty continuation line
    at the end of a header, but it is confusing to humans
    looking at such messages, since it looks like a blank line.
    Reduce confusion by removing redundant white space at the
    end. */


> So basically, that message is all header and there's nothing that can be done
> about it. The space at the beginning isn't an illegal character and a
> non-empty line does not the end of headers make. hmm?


Precisely.

-- 
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book:    http://www.uit.co.uk/exim-book