Mailing List Archive

Re Exim, DMARC and Resent-From again.
Quoting Jeremy Harris via Exim-users (exim-users@lists.exim.org):
> > The exact message 'DMARC: no From: header' can be found in Exim
> > src/dmarc.c line 357 and on line 539 some lookup of dmarc_domain can be
> Show _all_ the debug output for that case, please

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Minimal Exim config: https://8n1.org/24994/be5e (e4-test.conf)
Example e-mail: https://8n1.org/24995/7760 (testemail_w_rf.eml)
Full debug *with* Resent-From: https://8n1.org/24996/8b21 (full_debug_with_resent_from.log)
Full debug *with out* Resent-From: https://8n1.org/24997/9bb4 (full_debug_without_resent_from.log)

I used '<owner-test2+ssmeenk=freshdot.net@simplelists.com>' as envelope
sender.

See what changes when you remove the 'Resent-From' header and inject it
again. DKIM breaks, but removing that header also triggers the 'no From:
header' message from the DMARC code. This, combined with the fact that
it incorrectly finds 'nl-ix.net' as DMARC domain when that header *is*
present makes me believe there's something wrong in de code somewhere.

I have been poking at this quite a bit but can't get my fingernails
behind it yet. If there's anything i can do, compile code wise, please
let me know.

Love to hear from you!

Regards,
-Sander.
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Re: Re Exim, DMARC and Resent-From again. [ In reply to ]
On 22/08/2023 15:10, Sander Smeenk via Exim-users wrote:
> Quoting Jeremy Harris via Exim-users (exim-users@lists.exim.org):
>>> The exact message 'DMARC: no From: header' can be found in Exim
>>> src/dmarc.c line 357 and on line 539 some lookup of dmarc_domain can be

The message has other Resent- headers (I see at least -message-id and -date)
and because of that, Exim thinks it should have a Resent-From:
The latter seems to be the one it passes, in this case, to the DMARC evaluation
as the From: to use. So a null object gets passed, and we get the complaint
"no From:".
--
Cheers,
Jeremy


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