[MlMt] Bad GPG signature when sending emails

[Manuel Kreutz]

Hello there

I run into an odd issue which appears to be related to an extra new line 
(\n) character being added around the PGP signature of an email. The 
en/decryption of emails is working fine, however signed emails sent via 
MailMate show a "Bad signature" when opening the message in MailMate or 
Apple Mail.

I noticed the following when running MailMate with `defaults write 
com.freron.MailMate MmDebugSecurity -bool YES`:

- sending an email calls `gpg2` to create a detached signature using the 
correct signing sub-key
- MailMate calls `gpg2` to validate the signature (passes with GOODSIG)
- MailMate calls `gpg2` to print the available keys based on the signing 
key
- the last two calls run again

The used example `Input String`, based on the emails content and the 
generated PGP signature, shows a length of 1025 characters during this 
process and a "Good signature" on both verification calls. Once the 
email arrived, MailMate shows "Bad signature for OpenPGP message" and 
the terminal debug output shows that 1027 characters were passed to 
`gpg2` which resulted in the "BAD signature" error.

Looking at the string GPG2 used to sign and validate, it appears the two 
character difference is a new line character "\n" around the "-----BEGIN 
PGP SIGNATURE .." part of the message. Removing those two characters and 
attempting to validate the email content + PGP signature via the command 
line works fine afterwards.

I am running MailMate 1.7.2 build 4021 with latest GPGTools on OSX 
10.9.1. The MailMate preferences have "Experimental features", "OpenPGP" 
and "SpamSieve" support enabled. I use a RSA key with the secret key 
removed, along with two separate RSA sub-keys for encryption and 
signing.

I was unable to find other users having the same problem on this mailing 
list and the google was no help, so I would appreciate any insight on 
what could cause this problem (and how to fix).

-manuel