Bug 407111

Summary: EWS compose Emails with S/MIME signature certificates with wrong Content-Transfer-Encoding: 7Bit instead of base64
Product: [Frameworks and Libraries] Akonadi Reporter: themroc <rauchweihe>
Component: EWS ResourceAssignee: kdepim bugs <pim-bugs-null>
Status: REPORTED ---    
Severity: normal CC: krissn
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Ubuntu   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: diff between local and server version of sent Email

Description themroc 2019-04-30 20:24:32 UTC 
Created attachment 119756 [details]
diff between local and server version of sent Email

EWS compose/send Mails with S/MIME signature certificates with wrong Content-Transfer-Encoding: 7Bit instead of base64


When I send a signed e-mail with S / MIME signing certificates, the certificate will not be recognized by any other mail client, including Kmail on other machines.
An invalid signature is always displayed.
Outlook indicates, that the message content was changed after creating the signed mail and therefore the signature can not be verified.

In addition, only on the computer from where I have sent the mail in Kmail with the EWS resource in the sent folder the signature is displayed as valid.

On another computer with the same EWS resource, the sent mail in the sent folder will be displayed as invalid.

This means, however, that Outlook is right and the message content was changed later when it was sent.

And indeed, the message source text on both machines in the sent folder is not identical.

On the computer from where I sent, will keep the original written e-mail. On the other computer, the sent e-mail is downloaded from the server.

Comparing the two different e-mail source texts, there is only one relevant difference:

< Content-Transfer-Encoding: 7Bit
---
> Content-Transfer-Encoding: base64


The really sent version has this line:
> Content-Transfer-Encoding: base64


I then came up with the idea to force kmail to switch to the "Content-Transfer-Encoding: base64" when writing the mail.
By adding special characters in the message text I reached it.
Then the version sent in Kmail will no longer be different from the version sent to the server. Both have "Content-Transfer-Encoding: base64".

And then the signature is displayed as valid in all other mail programs and in kmail on other computers!

I have test this on Kubuntu 18.10 and Kubuntu 19.04

E.g for Kubuntu 19.04:

Operating System: Kubuntu 19.04
KDE Plasma Version: 5.15.4
KDE Frameworks Version: 5.56.0
Qt Version: 5.12.2
Kernel Version: 5.0.0-13-generic
OS Type: 64-bit