Content-Type: multipart/mixed seems to force base64 encoding somehow in Dkim.sign(mail) #32
Description
I have a huge message from aliexpress that when passed through Dkim.sign comes out encoded as base64 and gmail doesn't really like it. If i change the content type to "multipart/alternative" it doesn't end up as base64. I tried to shink it down but that doesn't impact it.
here's the test msg redacted a bit
Received: from out24-13.mail.alibaba.com (out24-13.mail.alibaba.com [115.124.24.13])
by myemail.net (Postfix) with ESMTP id C0EE340438
for bob@bob.com; Mon, 8 Nov 2021 14:05:19 +0000 (UTC)
DKIM-Filter: OpenDKIM Filter v2.10.3 myemail.net C0EE340438
Authentication-Results: myemail.net;
dkim=pass (1024-bit key) header.d=mail.aliexpress.com header.i=@mail.aliexpress.com header.b=aqadJZh+
X-AliDM-RcptTo: YWI1MzdjMWE5NzRmMzQ0YzU4Yzc5ZjU1ZDRmYWI1NDk4QGJybmcudXM=
Feedback-ID: default:present_ae@mail.aliexpress.com:batch:13
DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed;
d=mail.aliexpress.com; s=s1024;
t=1636380318; h=Date:From:To:Message-ID:Subject:MIME-Version:Content-Type;
bh=ir/1fYnPPk+nKtectnb5YsqowhiW9rE7NTu4dGwaXeY=;
b=aqadJZh+vBA1XUX2bye/ZDsukKYQaOOqpTb9NJVYc4qe+dKpNxs2rpdKQVFc/p0OouHn4NAmeRv3rRqzmS8TUdEAAMCplHhBoAEs9UN1nWLQ0M0YcM14O1SySV4W/5wTpAzM/Q7ytLXh4Yx/0DN/h00/6cA8NvDZX2LTlPo2xWI=
X-EnvId: 194285051284
Received: from ae-buyer-user9f74-xxfn8(mailfrom:present_ae@mail.aliexpress.com fp:SMTPD_----0owGdlt)
by smtp.aliyun-inc.com(127.0.0.1);
Mon, 08 Nov 2021 22:05:17 +0800
Date: Mon, 8 Nov 2021 06:05:17 -0800 (PST)
From: AliExpress <present_ae@mail.aliexpress.com>
To: bob@bob.com
Message-ID: 3197biz_price_reduce_edm:0:0_4659037$074e0a7ae314499f960e4e47fa388cfa
Subject: New price alert for bob
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="----=_Part_133763949_30120080.1636380317614"
------=_Part_133763949_30120080.1636380317614
Content-Type: text/html;charset=utf-8
Content-Transfer-Encoding: quoted-printable
<!--aeug_edm_19435#${houyiJobId}--><!doctype html>
<html xmlns=3D"http://www.w3.org/1999/xhtml" xmlns:v=3D"urn:schemas-microso=
ft-com:vml" xmlns:o=3D"urn:schemas-microsoft-com:office:office">
<head>=20
<meta name=3D"viewport" content=3D"width=3Ddevice-width, initial-scale=3D=
1">=20
</head>=20
<body style=3D"background: #fff; background-color: #fff;">=20
</div> =20
</body>
</html><div style=3D"display:none"><img style=3D"display:none" src=3D"http:=
//ae.mmstat.com/ae.edm.edm_open?tracelog=3Drowan-ae_usertouch-aeug_edm_1943=
5_1_en_US-2021-11-08&rowan_msg_id=3D3197biz_price_reduce_edm:0:0_4659037$07=
4e0a7ae314499f960e4e47fa388cfa"/></div>
------=_Part_133763949_30120080.1636380317614--
here's the code that calls the signing
def sign(mail_pipe) do
if mail_pipe.domain == :error, do: raise "signing... domain error"
[rsaentry] = :public_key.pem_decode(File.read!(@privkey))
new_mail = %MimeMail{headers: mail_pipe.stripped_headers,body: mail_pipe.new_mm.body}
to_addresses = Enum.map(mail_pipe.to_list, fn(x) ->
x.new.address
end)
key = :public_key.pem_entry_decode(rsaentry)
#
# Seems fine until this point and it gets base64 encoded
#
signed_mail = DKIM.sign(new_mail,key,d: mail_pipe.domain,s: "mail")
raw_signed_mail = MimeMail.to_string(signed_mail)
Idg.MP.print_report(mail_pipe)
r = {mail_pipe.from.new.address,to_addresses,raw_signed_mail}
end