dkim body hash fails

[apezio]

🐛 Bugreport

Using the latest code (only one I have tried) emails sent with cypht fail dkim verification. The error is "body hash did not verify"

I think cypht (or one of its libraries) is forgetting the end of the content-type boundary. In my example I am sending as text/plain but the same happens when sending as html or markdown.

Example body of email from cypht (quotes are mine):

"--EEbummS0cqZsZ4jVahUu7l5RWlOhhkRh8dQZC7PRP7RhHV2mfCWQgsiYKPLd Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable

dkim test 25"

and here it is at a destination:

"--EEbummS0cqZsZ4jVahUu7l5RWlOhhkRh8dQZC7PRP7RhHV2mfCWQgsiYKPLd Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable

dkim test 25

--EEbummS0cqZsZ4jVahUu7l5RWlOhhkRh8dQZC7PRP7RhHV2mfCWQgsiYKPLd--"

I am debugging the issue via opendkim's /etc/opendkim.conf options:

KeepTemporaryFiles yes TemporaryDirectory /tmp/

This saves a copy of the body before and after it is sent.

My theory is that either opendkim or sendail is trying to 'fix' the missing boundary by adding the last "--EEbummS0cqZsZ4jVahUu7l5RWlOhhkRh8dQZC7PRP7RhHV2mfCWQgsiYKPLd--" which invalidates the dkim body hash.

I could be totally wrong and it could be something else. Something to do with CR/LF's, or an encoding / canonicalization issue.

Version & Environment

Rev: [10813]

OS: [cent os 7]

Steps to reproduce

1. Have opendkim running and correctly configured to sign outgoing emails.
2. Send any message to a gmail.com address.
3. View the message on gmail and click 'show original' check the dkim status.
4. Compare the message before it is mailed by cypht and the message at the destination.