Univention Bugzilla – Bug 40210
Prevent screenshots of teacher's computer
Last modified: 2017-01-10 11:46:40 CET
A customer asked if it is possible to prevent screenshots or the supervision feature for windows clients which are used by a teacher (teacher is logged on). Quick and dirty workaround: host# cd /usr/share/pyshared/univention/management/console/modules/computerroom host# diff -u __init__.py.ORIG __init__.py --- __init__.py.ORIG 2015-12-10 12:47:24.751279284 +0100 +++ __init__.py 2015-12-10 13:13:14.450585803 +0100 @@ -542,7 +542,7 @@ """ tmpfile = computer.screenshot - if tmpfile is None: + if tmpfile is None or computer.isTeacher: # vnc has not (yet) received any screenshots from the computer # dont worry, try again later self.finished(request.id, None)
A solution for the product would return a special screenshot that indicates that the screenshot feature has been blocked on purpose. Additionally (if possible) this should not be limited to teachers but a group/several groups of users.
Attendee in workshop refered to it and said that it is "big problem at one school" he administrate. FYI: Using paedML (UCS 3.2-8)
Created attachment 7688 [details] Patch against UCS@school 4.1 source package Nearly complete patch against UCS@school 4.1. Via UCR variables, the admin is now able to a) define groups for whose members no screenshots are shown or b) define that for teachers no screenshots are shown. Additionally if no screenshot is available yet, a (hopefully) meaningful replacement is delivered to the browser. The required default images are not included within the patch: /usr/share/ucs-school-umc-computerroom/screenshot_denied.jpg /usr/share/ucs-school-umc-computerroom/screenshot_notready.jpg The patch has to be rebased/adapted for UCS@school 4.1 R2 since the handling of user roles changes.
Customer (08505) asked for it by mail.
*** Bug 41625 has been marked as a duplicate of this bug. ***
Customer reported name "null" under the supervision image in some case. At least if the screenshot view is not ready. Should be something like "User not yet known." or be empty.
ucs-school-umc-computerroom.yaml: r71031 | Bug #40210: prevent to create screenshots of certain users ucs-school-umc-computerroom (8.0.3-2): r71179 | Bug #40210: prevent to create screenshots of certain users r71033 | Bug #40210: prevent to create screenshots of certain users r71031 | Bug #40210: prevent to create screenshots of certain users
Please document the UCR variables or other customizable options here at the bug.
(In reply to Sönke Schwardt-Krummrich from comment #8) > Please document the UCR variables or other customizable options here at the > bug. +[ucsschool/umc/computerroom/hide_screenshots/groups] +Description[de]=Kommaseparierte Liste mit Gruppennamen, für deren Mitglieder keine Screenshots im Computerraum-Modul angezeigt werden sollen (Standard: Domain Admins) +Description[en]=Comma separated list of group names, for whose group members no screenshots are shown in computer room module (Default: Domain Admins) +Type=str + +[ucsschool/umc/computerroom/hide_screenshots/teachers] +Description[de]=Der Wert "true" verhindert die Anzeige von Screenshots von Lehrer-Rechnern im Computerraum-Modul (Standard: false) +Description[en]=By setting this variable to "true", screenshots of teacher's computers are not shown in computer room module (Default: false) +Type=bool
OK: manual tests: UCRVs ucsschool/umc/computerroom/hide_screenshots/groups and ucsschool/umc/computerroom/hide_screenshots/teachers work as described OK: advisory (added UCRV names in r72283)
UCS@school 4.1 R2 v7 has been released. http://docs.software-univention.de/changelog-ucsschool-4.1R2v7-de.html If this error occurs again, please clone this bug.