Bug 451036

SUMMARY
When opening an attachment (like an office document), the document gets saved into a temporary location but with read-write permissions. As a consequence, software like libreoffice opens the file for editing. If the document would be read-only permissionwise, libreoffice would open the file read-only.


STEPS TO REPRODUCE
1. Click on an attachment (office document)
2. Choose "Open"
3. libreoffice opens the document
 
OBSERVED RESULT
The file is opened in libreoffice in read-write mode; all changes to the file are saved in the temporary location.

EXPECTED RESULT
The file should be saved read-only (i.e. with 0400 instead of 0600) in the temporary location as that makes libreoffice open the file in read-only mode for viewing only. If the user wants to edit the document, libreoffice asks the user to save the file first.