On Tue, Jul 21, 2020 at 08:18:21 +0900, TACHIBANA Masashi wrote:
> Hi,
>
> Thank you for your reply.
>
> I hope this bug to be fixed soon. :)
It is a tricky one because as far as I can tell, the From header is invalid.
So, we have to figure out the best way to handle such input.
The input is invalid because '@' is not allowed by the RFC to be in the name
portion of an email address without quoting. In other words, these are ok:
t...@example.com
<t...@example.com>
Test <t...@example.com>
"t...@example.com" <t...@example.com>
but this one is bad:
t...@example.com <t...@example.com>
In your case, the name is encoded but not quoted so even though the email
contains:
=?UTF-8?B?dXNlcjJAZXhhbXBsZS5jb20=?= <us...@example.com>
the parser sees:
us...@example.com <us...@example.com>
Which is invalid.
Dovecot parsing needs to be improved, but as I already mentioned it is an
improvement to handling of malformed input. So, as a workaround, if you
control the software/system that generates these emails, try to change it so
it doesn't generate headers that are invalid. As far as I can tell, the
parser in Dovecot handles those just fine.
Jeff.
> Thank you.
>
> Tachibana
>
> ----- Original Message -----
> > On Mon, Jul 20, 2020 at 09:43:12 -0400, Josef 'Jeff' Sipek wrote:
> > > On Mon, Jul 20, 2020 at 20:24:13 +0900, TACHIBANA Masashi wrote:
> > ...
> > > Thanks for the report. I reproduced it locally, but I'm not sure what is
> > > causing it yet.
> >
> > Alright, it is actually a parsing bug. The problem seems to be when the
> > code encounters a "name <address>" format where the name is a valid address.
> > This accidentally makes the parser stop parsing - making any additional
> > addresses ignored.
> >
> > E.g.,
> >
> > t...@example.com <t...@example.com>, Name <ot...@example.com>
> >
> > The parser stops after the first address's name thinking it is just a bare
> > address (without a name). That is, after the first loop iterating while
> > parsing, the "cursor" is at the first space and not at the comma.
> >
> > /- parsing should stop here
> > v
> > t...@example.com <t...@example.com>, Name <ot...@example.com>
> > ^
> > `- parsing stops here
> >
> > This is obviously wrong. I'll have to dig in more to figure out what it
> > will take to fix this.
> >
> > Thanks again,
> >
> > Jeff.
> >
> > --
> > FreeBSD 12.1
> >
> --
> TACHIBANA Masashi QUALITIA CO., LTD.
> mailto:tachib...@qualitia.co.jp
>
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>
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