GpgOL deletes message body in S/Mime signed mails if Outlook is configured for .txt
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Description

[Win10prof(64), Outlook-2016(32), Gpg4Win 3.1.10/ GpgOL 2.4.2]

Outlook receives a html mail, signed with valid S/Mime signature.
GpgOL verifies signature => working, green trusted sign, html body content is shown.

BUT:
If Outlook-2016 is configured for receiving TXT-only in 'Trust center/Email security' some HTML mails are trunctated, html body is deleted and cannot be recovered, content is lost!

If S/Mime signed mail has been received earlier as html mail without OL conversion and Outlook's configuration has been changed to TXT-only afterwards, after re-opening those mail bodies are deleted/ trunctated too, empty content. Mail headers are still present.

It must be caused by GpgOL's interaction with OL's TXT conversion. If viewing same mail in webmail account by browser before downloading it to Outlook/GpgOL, everything is ok.
https://wald.intevation.org/forum/forum.php?thread_id=2120&forum_id=84&group_id=11

Maybe another related issue is sending S/Mime signed txt only mails:
Body content is deleted also in OL's 'sended objects'.
If indexing those mails for example with common 'Copernic Desktop search CDS' or 'MailStore', it is indexed twice:

  1. as empty mail, no content
  2. as .txt file namend 'GpgOL_MIME_structure.txt' with included but not readable S/Mime body.

https://wald.intevation.org/forum/forum.php?thread_id=2117&forum_id=84&group_id=11

Regards, Chris

Details

Version
GpgOL 2.4.2
gnupgpacker updated the task description. (Show Details)
gnupgpacker updated the task description. (Show Details)Nov 1 2019, 6:01 PM
gnupgpacker updated the task description. (Show Details)
aheinecke triaged this task as Normal priority.
aheinecke added a subscriber: aheinecke.

Thanks for the report but I cannot reproduce the issue :-/. In multipart alternative mails GpgOL takes the text part if text mode is set in Outlook.

For HTML only mails GpgOL will indeed just put the HTML in the body of the mail. That might look broken but I don't think it is data loss.

With Gpg4win-3.1.11 we go through some length to ensure that Mails opened by GpgOL can still work with other Mail clients like the Outlook web interface. I think this could also help with this issue and indexing because we keep the S/MIME mails marked as S/MIME mails and no longer use our own message class. 3.1.11 should be released tomorrow.

Can you provide a sample mail where this occurs as a .msg file? Ideally before it has been touched by GpgOL.

Thanks for examination.
Providing an 'untouched .msg' seems to be complicate because OL receives several encrypted mails all day long, so GpgOl must be activated for common use. Additional: To avoid this issue, .txt mode has been deactivated, .html is allowed without downloading foreign items or pictures.

Describben issue had been detected for example while receiving registration mails from Centrum Certyfikacji <autoresponder2@certum.pl> signed with S/Mime (it is a Polish CA).

Example:
.html mail has been received from certum.pl with Outlook-2016(32) in .txt-only configuration.
Mail body is empty in Outlooks preview and after opening mail itself.
(Another mail has been ok in T-Online web portal before it downloading to Outlook by POP3s.)
Sources show differing content-type/ protocol.
After archiving with MailStore the differing content type is shown too, message body is still empty.

Date: Thu, 10 Oct 2019 12:24:30 +0200 (CEST)
From: Centrum Certyfikacji <autoresponder2@certum.pl>
To: mail@xxx.de
Message-ID: <760840xxx.1485057.15707030xxx53@vm-uma-r7-mailing-0101.net.certum.pl>
Subject: =?UTF-8?Q?Certyfikat_zosta=C5=82_utworzony?=
MIME-Version: 1.0
Content-Type: text/plain;
protocol="application/pkcs7-signature";
micalg=sha1;
boundary="----=_Part_1485xxx_147346321.15707030xxx55";
charset="utf-8"
X-MailStoreOLK-Original-Content-Type: multipart/signed;
boundary="----=_Part_1485xxx_147346321.15707030xxx55";
protocol="application/pkcs7-signature"; micalg=sha1
Content-Transfer-Encoding: 7bit
X-MailStoreMapiMimePostProcessor: 12.0.3.14426

I will stay tuned and i will re-evaluate activated .txt-mode in Outlook 2016 with new version 3.1.11.
Problem: GpgOl is activated. If receiving a broken mail with this issue (rare!), it has been touched from OL and GpgOl...

Kind regards!