[Rt-devel] Bug: Forward + GnuPG sign = illegal MIME encoding base64

Otmar Lendl ol at bofh.priv.at
Tue Oct 20 10:07:04 EDT 2009

This was a bit tricky to debug:

We kept getting complaints about empty forwards from our RT 3.8.2 / RTIR
installations. Testing Forwards manually (/RTIR/Forward.html) showed the
desired attachment, though. At least in mutt. Not in Thunderbird.

Finally Amavis tipped us off: "illegal MIME encoding [base64] for message/rfc822".

It turns out that an attachement of type message/rfc822 must
not be encoded by itself. Plain RT is fine, it uses "binary" as
encoding. Nothing wrong about that.

Now, we do have GnuPG signing enabled for this queue, and thus the message gets
passed through the signing engine, and here (quite understandable), the code
wants to play it safe and recodes to base64. And not the individual leafs of the
MIME tree (which would be fine), but the message/rfc822 part itself. 

Bad karma.

The kolab people also ran into a similar issue some time ago, see:

Anyway, I do not have a good solution for that, for the moment I decided
to simply disable signing for forwards.

Does someone else have a good idea where to tweak the gnuPG code to get
this right?


-=-  Otmar Lendl  --  ol at bofh.priv.at  --  http://lendl.priv.at/  -=-

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