Violation maximum line length (RFC 2822) for forwared mails

[Ingo Klöcker]

On Mittwoch, 3. März 2021 23:14:33 CET Rainer Dorsch wrote:
> Am Mittwoch, 3. März 2021, 23:03:56 CET schrieb Ingo Klöcker:
> > On Mittwoch, 3. März 2021 21:50:53 CET Rainer Dorsch wrote:
> > > Hi,
> > > 
> > > I see from time to time that mail I want to forward as attachment get
> > > rejected by my exim mail server due to a violation of the maximum line
> > > length. This is specified as 998 characters in RFC 2822
> > > 
> > > https://tools.ietf.org/html/rfc2822#section-2.1.1
> > > 
> > > I observed that so far just if I try to forward mails as attachment. The
> > > original email which I forward seems to be compliant (I have here one
> > > with
> > > a maximum line length of 94 characters).
> > > 
> > > I observed this on kmail in Debian buster and in Debian bullseye, i.e.
> > > 18.08.3 and 20.08.3, respectively.
> > 
> > I can reproduce this with KMail 5.16.1 (openSUSE Tumbleweed). Apparently,
> > KMail puts each header field of the forwarded message in one line even if
> > this results in lines exceeding the limit.
> 
> yes, I double checked: I have spamassassin inserting an X-Spam-Report line
> which is e.g. 1833 characters long. This exceeds the 998 characters per line
> clearly and basically breaks the forward as attachment function for most of
> the mails I receive at least.
> 
> > > Is that a known kmail issue?
> > 
> > I guess that would be
> > https://bugs.kde.org/show_bug.cgi?id=409169
> > and
> > https://bugs.kde.org/show_bug.cgi?id=411141
> 
> Would you agree that the example I have is slightly different? It is the
> header of a forwared mail (as attachement) not the mail header of the mail
> itself.

Well, the symptom is the same: too long header. It doesn't really make a 
difference whether it's the header of an attached message or of the actual 
message. Your use case "Forward as attachment" is slightly different from the 
two bug reports. The actual problem in the code is likely the same in all 
cases: KMail does not properly (if at all) fold long header fields.

Regards,
Ingo
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