Re: Broken DomainKey Implementation

[Matt Simpson <net-qmlist@jmatt.net>]

At 1:42 AM 4/7/07, Russ Nelson wrote:
> Matt Simpson writes:
>  > My excuse for "munging" the message is that I'm running ezmlm lists,
>  > with the qmail verh patch to add a customized "List-Unsubscribe"
>  > header for each subscriber.
>
> No problem.  Insert a Sender: header and re-sign.


I'm already inserting a Sender header and re-signing.  The problem 
is, that since the List-Unsubscribe header is modified by the verh 
patch in qmail-remote to include the individual subscriber's address, 
the signature added by qmail-dk becomes invalid.  If a single copy of 
the message is signed, and then queued for distribution to hundreds 
of subscribers, and then qmail-remote changes a header on the copy it 
sends to each subscriber, the only way for that signature to remain 
valid is if the header "munged" by qmail-remote+verh is to exclude 
that header from the signature.  The other option is to sign the 
message in qmail-remote after verh munges the header.