Signature broken for replies

From: John Massai <massaijohn_at_gmail.com>
Date: Fri, 18 Sep 2015 17:24:09 -0700

Hello,

Testing opendkim signatures by looking at Gmail authentication
results, normal messages are passing with dkim success. But if the
message is a reply, the dkim verification fails.

The extra headers included in the signature are In-Reply-To and
References. I hacked the MUA and caused those headers to be absent
while sending another reply and the signature worked again.

Those fields look something like this:

In-Reply-To:
 <GRPhs2139td_7V6He90TLhrC1Rbh0oSwgHEgNferLJnwLtm+1=d_at_mail.gmail.com>
References: <439kf8b8h20hg098sg798ih39823hig78.host_at_my-domain.com>
    <GRPhs2139td_7V6He90TLhrC1Rbh0oSwgHEgNferLJnwLtm+1=d_at_mail.gmail.com>

Only other thing that could affect this is having the OversignHeaders
set to From?

What can I do to fix this?
Received on Sat Sep 19 2015 - 00:24:24 PST