Fwd: Munge from (was Re: [mlmmj] List server DKIM)

Sorry, my mail client doesn’t like adding replies below quotes.

Seems to me Jon Fairbairn is on the right lines (below).  

Just dropping DKIM headers creates a problem, SPF is broken too, and if sender has a DMARC policy of reject, the message will get thrown away.  

Removing and then adding is OK provided “from” is changed to the list. The server running the list can only add DKIM for domains it manages.  

Changing “from” fixes SPF and DKIM.  

Is that right?  

--  
Martin Brampton  

On October 3, 2019 at 6:38:31 PM, Jón Fairbairn ([email protected](mailto:[email protected])) wrote:

> On Thu, 3 Oct 2019 18:04:48 +0100 you wrote:
> > My list server is sending out mail, and I have configured to
> > add a footer, a prefix and mailing list headers.
> >  
> > I don't know if it is those additions, but the messages
> > received by list subscribers are failing DKIM checks with
> > wrong body hash.
>  
> Yes, those additions will cause that.
>  
> > Is there a way to fix this please?
>  
> One way is not to make those additions, but that isn’t what you
> want :-/
>  
> I have implemented "munge from", which replaces the from field
> with the address of the list and adds a comment to it containing
> the name and email address of the sender, so that you can remove
> the DKIM signature and solve this problem (and add you own if
> you want). I was waiting to see if there was any activity on the
> list before posting about it.
>  
> So my general question is, is this something that people want,
> and if so, where should I send the patch? I’m not familiar with
> Mercurial, and I’m not really a C programmer (I think I last
> wrote C in anger in about 1987), so it would be best if someone
> who is were to review it.
>  
> — Jón

Sorry, my mail client doesn’t like adding replies below quotes.

Seems to me Jon Fairbairn is on the right lines (below).

Just dropping DKIM headers creates a problem, SPF is broken too, and if sender has a DMARC policy of reject, the message will get thrown away.

Removing and then adding is OK provided “from” is changed to the list. The server running the list can only add DKIM for domains it manages.

Changing “from” fixes SPF and DKIM.

Is that right?

--
Martin Brampton

On October 3, 2019 at 6:38:31 PM, Jón Fairbairn ([email protected] ) wrote:

On Thu, 3 Oct 2019 18:04:48 +0100 you wrote:

My list server is sending out mail, and I have configured to

add a footer, a prefix and mailing list headers.

I don't know if it is those additions, but the messages

received by list subscribers are failing DKIM checks with

wrong body hash.

Yes, those additions will cause that.

Is there a way to fix this please?

One way is not to make those additions, but that isn’t what you

want :-/

I have implemented "munge from", which replaces the from field

with the address of the list and adds a comment to it containing

the name and email address of the sender, so that you can remove

the DKIM signature and solve this problem (and add you own if

you want). I was waiting to see if there was any activity on the

list before posting about it.

So my general question is, is this something that people want,

and if so, where should I send the patch? I’m not familiar with

Mercurial, and I’m not really a C programmer (I think I last

wrote C in anger in about 1987), so it would be best if someone

who is were to review it.

— Jón