Re: New "Old-" headers emerging from the horizon
Bernd Wurst <[email protected]>
| Newsgroups | gmane.mail.imap.courier.general |
|---|---|
| Message-ID | <[email protected]> |
Am 27.01.24 um 15:00 schrieb Sam Varshavchik: > The problem I see here is this part: > # If the original email message had a DKIM signature, it has already been > # evaluated. Removing the BIMI-Location header at this point should not > # invalidate the signature since it should not be included within it per > this > # spec. > > It's fairly simple to adjust the headers upon receipt, in submit.C, > where all the other headers are renamed to Old-. > > But then that's what the mail filter will see. According to the spec, those two headers, BIMI-Location and BIMI-Indicator are not supposed to come from the sender but are set by the (last) receiving MTA to tell "its MUA" which logo to display. This is done by checking the validity of the other BIMI-headers. As long as a server does not have BIMI validation functionalty or has no MUA that trusts it, it seems to be completely irrelevant if those headers are removed or not. Spec says: > The BIMI-Location and BIMI-Indicator headers MUST NOT be DKIM signed. This header is untrusted by definition, and is only for use between an MTA and its MUAs, after DKIM has been validated by the MTA. Therefore, signing this header is meaningless, and any messages with it signed are either coming from malicious or misconfigured third parties. So no filter wants to see these headers, no signature depends on them being there or being unaltered. Maybe the MTA should just leave those headers alone and if someone implements a BIMI validation filter, this filter should take care to remove those old headers and just put his new ones in place. _______________________________________________ courier-users mailing list [email protected] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users