dkim: generated header not properly formatted #23
Description
Hi, I'm playing with this library and I'm incurring in a strange issue.
In some case, when I try to generate a DKIM signature, the generated header get an extra "\r\n" that makes the mail invalid.
For istance, if I try to sign this email:
From: test@test.com
To: test@test.com
Subject: Send Test
Message-ID: <xxxxx@xxxxx>
Return-Path: <test@test>
Date: Mon, 09 Mar 2020 17:04:25 +0100
Message Body
I got this signed message
DKIM-Signature: a=rsa-sha256; bh=opmXtA9gMR670DN8CmqNEL8Q4RBdtB/ULgaN/SkjFn
0=; c=simple/simple; d=mail.ludusrusso.space; h=From:To:Subject:Message-ID:
Return-Path:Date; s=brisbane; t=1583769865; v=1; b=JHLkTc5vtTRA4udN9sAMcPWx
TLLfqQ6ry++3GLbcWjhR769N4hK7kaL2P1iseXaoVbQpxVGzZYz9x5P8q9brfYZEuuQciWPvk1n
k99E685amWpMsSqUnsHWifpeFtZpNHwPSVWJp03Kmeq2wE85+Fauq/P+7bVfRa/N1hUIFUpk=;
From: test@test.com
To: test@test.com
Subject: Send Test
Message-ID: <xxxxx@xxxxx>
Return-Path: <test@test>
Date: Mon, 09 Mar 2020 17:04:25 +0100
Message Body
notice that the extra black line added before From header makes the message to be worngly interpreded by a receiving SMTP.
The issues seems related to the length of the header, in fact if I try to add (or remove) headers from the message it works properly:
DKIM-Signature: a=rsa-sha256; bh=bvW0aiEWdP0ie2rawBb+IiTxlHI9KgEIYjEYTGzMRa
0=; c=simple/simple; d=mail.ludusrusso.space; h=X-Extra-Header:From:To:Subj
ect:Message-ID:Return-Path:Date; s=brisbane; t=1583770035; v=1; b=Rer+wvDGH
tVS7SwYC5kdouGz6Su0B0iEvegWcwQe4GcMERi5QfJWV8hDnjappa8KX1fst2YmhFjUST+Ai3zM
dyH1iKJiIm78Yt0n3c1f/95bP9Ey6xc1t1zYcJm3t/zQ8Sho/XjPRqdilOJYXPZB18y5JILnV67
69eKFcsnzmic=;
X-Extra-Header: extra header
From: test@test.com
To: test@test.com
Subject: Send Test
Message-ID: <xxxxx@xxxxx>
Return-Path: <test@test>
Date: Mon, 09 Mar 2020 17:07:15 +0100
Longer message body
Note the extra header here.
If you give me some tips, I could try to solve the issue and submit a PR!
It seems to me that the issue is due to the 76 char limitation of the message line.