Alin Năstac wrote:
> Murray S. Kucherawy wrote:
>> The use of the "SubDomains" option is intended to generate signatures
>> for arbitrary subdomains using a key advertised by the parent
>> domain.  That is, mail from "x.example.com" will be signed using
>> "d=example.com".  It's intended as blanket coverage for subdomains
>> you may not know are in use.
>>
>> If that isn't what you want, then I believe you have more stringent
>> requirements than the DKIM subdomain signing concept supports, and
>> you should include "x.example.com" explicitly in your signing domains
>> list (and advertise a specific policy for it).
>
> I have dkim-milter-2.4.2.
>
> What I really want is a  "dkim=strict; handling=deny" SSP record.
> Problem is dkim-milter-2.4.2 fails to verify subdomains signed with
> one of domain's selector and I believe is due to the lack of
> "[EMAIL PROTECTED]" tag in DKIM-Signature header. However I didn't
> analysed the source code, so it is more like a educated guess.
>
> Since dkim-milter gives me the option to sign subdomain messages,
> verification of such messages should succeed, don't you think? More so
> if the signer and verifier use the exact same DKIM software and
> therefore it couldn't be due to different interpretation of the DKIM
> specification.
>
I've analyzed the code and conclude that dkim_policy() is to blame. More
precisely, a signature is valid only if signer domain == the domain part
of the sender address. I think it should also accept a signature if both
the following conditions are satisfied:
  - dkim->dkim_domain is a subdomain of sig->sig_domain
  - SSP entry of the sig->sig_domain doesn't have t=s

Will you accept a patch that does just that?  For proving my point (that
DKIM should also accept valid domain signatures on subdomain messages),
please see example from the appendix A of the RFC 4871.

Attachment: signature.asc
Description: OpenPGP digital signature

-------------------------------------------------------------------------
Check out the new SourceForge.net Marketplace.
It's the best place to buy or sell services for
just about anything Open Source.
http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace
_______________________________________________
dkim-milter-discuss mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/dkim-milter-discuss

Reply via email to