Ask Slashdot: Ubuntu Lockdown Options?

First time accepted submitter clava writes "We have a desktop Java testing application that is going to be administering tests to students on lab computers running Ubuntu 10.x. These computers are used by the students for other purposes and we're not allowed to create special users or change the OS configuration. When the testing app is launched, we need to restrict users from exiting the app so they can't do things like search the internet for answers or use other applications. Is there a good way to put an Ubuntu machine in kiosk mode or something via our application and have exiting kiosk mode be password protected? Any ideas are appreciated."

Comments

Depends how locked-down

[Anonymous Coward]

I'm afraid if you want it actually locked-down, you're pretty screwed. You can't really disable things like switching to a tty with ctrl-alt-f1 without "changing the OS configuration."

Re:Depends how locked-down

[adamdoyle]

If you ask me, you don't really need to prevent users from doing those things. You just need to tell they're not allowed to, and then have your java app detect if those things have occurred and then take action from there. By "take action," I mean that you could either (a) make some kind of notation in the database so that you can penalize them, or (b) send an SMS message or email or something to the test administrator to alert them of the situation so that they can walk over and determine if the student is attempting to cheat.

Re:Depends how locked-down

[Anonymous Coward]

This can be done.

1. Insert a Windows 7 CD, format the drive, install the Windows 7 operating system. Via group policies and TweakUI, disable all settings and applications that you don't want users to access.

2. Take the Ubuntu CD and place it on the desk next the computer.

3. Place hot beverage of choice on Ubuntu CD, which will now be reffered to as the "coaster".

4. Proceed with Java tests.

Re:Depends how locked-down

[c 0xFF]

Disabling TTY switching is a pretty simple change, though, and won't affect the general use of the system.

In fact, you might as well use this to your advantage: start up a new X server instance, but don't start up the window manager. Run your java app in this server.

Now all a student can do is take the test -- there's no way to do anything besides take the test unless they can switch using ctrl-alt-F*, which has been disabled.

That's as near to a "kiosk mode" as I can figure.

Re:Depends how locked-down

[MurukeshM]

Hmmm... installing a whole 'nother OS is a neat way of sidestepping the 'not changing OS configuration.' Oh, wait! Troll sensor peaking.

Re:Depends how locked-down

[Zamphatta]

That would be smart for the learning environment AND to avoid legal issues from rich parents who are determined to get their kid a retest.

Re:Depends how locked-down

[Bent Spoke]

Disabling TTY switching is probably not necessary: It would only help them if they had a userid/passwd for the 'kiosk'

Re:Depends how locked-down

[mirix]

That would violate the 'no new user accounts or OS configuration' rule. troll harder.

Re:Depends how locked-down

[adamdoyle]

Or if you're feeling extra clever, you could straight up disable the keyboard and rely on the mouse for selecting answers. It would have to be enabled at the beginning for the user to enter his or her credentials, but then you could disable it during the actual test (there's no way to exit fullscreen with only a mouse), and then re-enable it upon completion. The site I linked to explains how to both enable and disable the entire keyboard programmatically. The linked site produces a shell script... In Java, you could run that shell script with: Process.Start(@"./scriptname.sh").

Re:Depends how locked-down

[Culture20]

Problem is, Windows' lockdown depends on Windows users being idiots.

Not true. True kiosk mode exists in Windows world. Do some regedits and gedit.msc foo and you'll have replaced explorer.exe with your choice of program (so it's the only program that can run), auto-logged in your user and disabled most of the ctrl-alt-del functions. Lock the bios, boot only from HDD, and padlock the computer, and the end users will have to bring in a set of lockpicks and a live CD to do anything normal with the computer.

Re:Depends how locked-down

[JDG1980]

Problem is, Windows' lockdown depends on Windows users being idiots.

That was true on Windows 9x (which more or less didn't have any such thing as security to begin with), but not on modern NT-based versions of Windows.

A previous employer of mine asked the I.T. department to lock down the internet. The solution to that problem was to install Firefox. Then I.T. got smart and also banned that.

Google "Software Restriction Policies." On all modern versions of Windows (including XP), you can set up a whitelist where only permissible programs are allowed to run. It then wouldn't be necessary to play whack-a-mole. Of course, if an employer decides to implement a draconian "no Internet" policy, then that employer is unlikely to get the best people, which explains why this IT department couldn't do anything right.

Re:Depends how locked-down

[Ethanol-fueled]

Hey, restriction policies can be done right. My new shop uses them to great effect, in fact, when combined with good firewall solutions. I was just pointing out that Windows is spaghetti code, where the browser is integrated into the shell and then not completely removed but blocked such that specific cases are missed and can be exploited out of the box. I'm no expert but am willing to gamble that Windows code up to Win7 does not contain any meaningful rewrites with regard to browser-shell integration - only more clever blocking. By the way, the file browser-URL trick I mentioned worked with XP, at least until installing one of the service packs.

*Nix at least has always had a meaningful modular approach. Both Operating systems can be exploited, but *Nix has better granularity and privilege escalation safeguards. The fact that submitter is mentioning Ubuntu says a lot, as it is the "Windows" of Linux.

Replying to Culture20 above you, regedit hacks are the same thing that is wrong with the current state of Linux usability. If you have to resort to that to do what you said, then you might as well run *Nix with less hassle. Also, why did Microsoft make it that difficult to replace IE?

Re:Depends how locked-down

[Vairon]

On most distributions, for security reasons, an unprivileged user cannot run an X server that uses video hardware. For example X servers that use nvidia drivers need to read and write to /dev/nvidia0 which is usually only readable and writable by root and users in the video group. He would need to place his users in the video group (not allowed) or make the X binary suid (not allowed) in order to do what you describe.

When you install distro X at home it probably installed your 1 local non-root user in the audio group, the video group, the cdrom group and a bunch of other groups that give you privileged access to hardware on the system. Any school sysadmin worth half his salary would never put all of his students in all of those groups. Schools tend to use AD, LDAP or NIS to centrally manage student users and groups. More than likely his lab machines have very few if any local users.

This ask Slashdot question doesn't have enough details to properly answer the question.

Re:Depends how locked-down

[Windowser]

Not sure about Ubuntu, but this is the way to do it in Debian :
Disable gdm
# update-rc.d -f gdm remove

modify /etc/rc.local, add these lines just before "exit 0"
** rc.local - BEGIN
su - username -c startx
reboot
** rc.local - END

add the file /home/username/.xsession
** .xsession - BEGIN
#!/bin/sh
/path/to/script/that/start/yourapp
** .xsession - END

make the .xsession executable
# chmod u+x /home/username/.xsession

Re:Depends how locked-down

[tepples]

you could straight up disable the keyboard and rely on the mouse for selecting answers.

Which doesn't help in cases of 1. answers that aren't multiple choice, or 2. having to accommodate people with mobility impairments where limitation to a mouse imposes an undue hardship.

Re:Depends how locked-down

[datavirtue]

It is a royal pain in the ass which requires the attention of a skilled developer and a very knowledgeable system admin. We setup a kiosk at the college using some crap software that basically just flips the registry and policy switches for you and it isn't much help. It sort of works, but all in all was not worth the trouble. VERY unreliable and difficult to use.

You can firewall port 80 and set permissions to prevent changes.

Re:Depends how locked-down

[ksd1337]

Why not just edit the initrc and remove all the geTTYs that aren't for X?

Re:Depends how locked-down

[ktappe]

you could straight up disable the keyboard and rely on the mouse for selecting answers.

Which doesn't help in cases of 1. answers that aren't multiple choice, or 2. having to accommodate people with mobility impairments where limitation to a mouse imposes an undue hardship.

Be fair, the restrictions on the implementation are severe: No OS mods one can kind of understand but you also can't create even a "testtaker" user account? As an OS deployment engineer I appreciate the former but I can't think of any justification for the latter.

Anyway, given these handcuffs, a multiple-choice test will just have to do I think. And believe me, you can make some pretty darn hard multiple-choice exams. Go try to get MS or Apple certified some time. 80 adaptive multiple choice questions that nobody is going to do well at unless they studied hard and/or know their stuff.

Re:Depends how locked-down

[jrumney]

True kiosk mode exists in the Linux world too, just not with the restrictions that the submitter placed "no special user accounts or changes to the OS configuration" is a pretty big restriction, no matter what OS you are trying to do this on.

Re:Depends how locked-down

[justforgetme]

here's another ridiculous idea:
watch them..
from behind!

Re:Depends how locked-down

[Bert64]

Kiosk mode is actually much easier on Linux...
Instead of a full blown desktop environment, simply supply a minimal window manager (or none at all) and the desired application. Remove all unnecessary packages from the system, and ensure any area the user can write to is mounted noexec and gets automatically cleared each time the machine is used.

Why?

[Anonymous Coward]

Why not let them use resources? Similar to what they will have available to them in the workforce.

Re:Why?

[bonch]

Because they're supposed to learn and internalize the concepts, not learn how to type search terms into Google or trade answers via IM.

Re:Why?

[pmgarvey]

Firstly the submitter didn't say if this was a programming exam, or what it was. It could be a test on memorising the capitals of African countries.

But more importantly is that allowing access to the internet doesn't just allow things like documentation, and other resources I might have in the workplace, but might allow me to ask my friend to email the entire solution, or even send the question to a guy in India and get the solution back for a fee. It's a comprimise between testing some memorisation and in the cases of some students, testing nothing at all.

Re:Why?

[jackhererUK]

Yes but why are they supposed to do that, what value does that give. Knowing how to get the information you need to accurately understand and answer the question is a very important skill to learn. If you use it regularly then you will remember it, if you don't use it regularly then you can't being able to quickly research and understand things is a very important skill.

Re:Why?

[LurkerXXX]

I guess you want that EMT to show up at your car crash to just google how to patch you up if he didn't pay attention in class. Better hope he doesn't lose signal to his cell phone.

Re:Why?

[Anonymous Coward]

Because somebody needs to provide those answers you find via Google. They don't just appear out of nowhere.

Re:Why?

[cupantae]

As a student with a test tomorrow, I would love if my lecturers would do this, because my tech skills would mean I'd get an advantage over most of my peers, so my score would be better.

But really, I'm not sure if it's all its cracked up to be. I certainly don't think 60 minutes, heads down, writing furiously (which I'll have tomorrow) is the best. Especially for a maths exam. However, I know that there is a lot to be said for the ability to easily recall a lot, and to know concepts and definitions back-to-front. Ultimately, a shakey memory of concepts and definitions, coupled with the ability to look them up, would surely lead to more mistakes gone unnoticed. These things are important, and deep understanding must be founded on some rote.

Re:Why?

[Hyperhaplo]

Not a good idea here. All web searches are logged and (sometimes) reviewed. Management tends to take a dim view about people 'looking things up'.

Stop laughing, that was a serious answer. Yes, managers actually ask 'why do you need to look that up, don't you know how to code?'

Trade answers?
You must be nuts.
See that silo that each and every person and each and every team has built around themselves? That's right, those silos are there to provide Job Protection. After all, if only you know how to run and maintain the system you have job security for life and no one can tell how much you are not doing.

Depressing, but real.

This 'testing scenario' will prepare them for what it is like to work in some organisations. Limited, restricted or no internet, and colleagues who see you as either their next step up the corporate ladder or a competitor / nark to sink at the next opportunity.

-----

As for this test - Go the customised Live CD every time. Quick, easy, customisable. Only requires being about to boot from CD or USB.

Re:Why?

[Ethanol-fueled]

I got poor-but-passing grades in high school, even as I got awards and letters of recommendation and was the only person who wrote "with style," because I knew then at that early age that college-educated folks could also be idiots, albeit ones who paid a lot less than we did later having to slog through the same tedium.

My college grades were much better, but only because I learned at my own pace, on my own terms. You think that some Adderall-popping punk who gets good grades forgetting everything they've learned after each final would make a "top-flight" employee? Could you possibly imagine that some people actually have lives, other priorities that don't revolve around serving their school and, later, their employer?

"Top-flight" employees indeed. What you want is a predictable, cocksucking slave who will not have the passion or imagination to be a threat to you after you hire them.

Re:Why?

[Mr. Freeman]

Some of my professors gave open-book exams. This allowed you to look up equations, material properties, etc. If you understood how to do all the work but were unsure of whether the last coefficient in a particular equation was positive or negative, this helped a lot. If you had no idea what you were doing then the book didn't help you at all. Brilliant exam, because in the real world you will have reference materials and you will sometimes forget things like the naiver-stokes equation.

However, the professors wouldn't in a million years consider making these tests open-internet. The internet allows answers to be shared, which doesn't allow for testing of individual students. In addition, the internet has a lot more information than in a textbook. A student may be able to find problems almost identical to those on the exam and simply copy the answer verbatim.

There's also a difference between being able to do your work with the assistance of a reference manual, and only being able to do your job if you have access to the internet.

Re:Why?

[Anonymous Coward]

As an EMT, it's rarely the "patching up" that requires reference - after all, cardiology can be explained thusly - "air goes in and out; blood goes round and round; variations are bad."

The trickier aspect is typically pharmacology - drugs people have been prescribed, known toxicity manifestations, drug interactions (polypharmacy and drug potentiation are a crapshoot when most of the public fails to understand that "diabetes" and "the sugar" are the same disorder and that, no, you cannot double a dose to make up for a missed dose...). Resources like Epocrates and others are utterly invaluable for assisting in patient care. Common drugs or those with recognizable etymologies are readily identifiable; it's typically niche drugs and worrying about interactions that create the biggest problem.

Does that mean the EMT is dependent upon the cellular connection? Negative. However, the EMT - and therefore the patient - substantially benefits when additional information is readily available in a portable, user-friendly package.

Re:Why?

[HopefulIntern]

Seconded. That sounds fucking horrible. All developers look things up from time to time. Nobody is expected to just code from memory, today's languages are far too complicated, especially considering most developers are expected to be proficient in more than one language.

Re:Why?

[bigstrat2003]

What the fuck are you talking about? I'm pretty sure there are plenty of jobs, right now, where you can not work for a bunch of Nazis. I have one, for one. Others do as well. This has nothing to do with putting up with shit to try to protect your livelihood; it's about avoiding employers you know treat their employees horribly.

Yes, ultimately you have to eat; you might have to take any job you can get. But you can (and should!) at least try to be in a work environment that doesn't make you want to stab yourself in the eyes. That's not "sparkles and fairies", that's common sense.

Boot from USB or CD-ROM?

[hawguy]

Create your own custom locked down kiosk boot image and require users to boot from that? Keep in mind that users might take the boot media home with them so they'll have a copy of the test app if you store it locally (as opposed to retrieving it from a website)

Here's an example:

http://jacob.steelsmith.org/content/ubuntu-kiosk-based-910

(I'm not vouching for this particular implementation, I just found it through a quick google search).

Re:Boot from USB or CD-ROM?

[phoenix_rizzen]

That's what we do. All our Linux stations boot off the network and use NFS mounts for everything. For government exams, teachers reboot the stations into "Exam Mode" which disables everything possible, launches a bare-bones X11 session with Firefox as the "WM", with all settings locked in, including an add-on that let's you specify a list of sites that are accessible, blocking access to everything else.

Took a few iterations to get the configuration locked down completely, but there's really no better way to find the holes than watch a class of students try to break it. :)

It's not bullet-proof, but we've made it hard enough that it's very obvious when a student is trying to break out of the box that anyone watching the lab will notice. :)

If you can't change the OS config, you can't lock it down.

Re:Boot from USB or CD-ROM?

[qeraser]

I have this installed on 20 laptops which are locked down to only my companies web sites for credit card payments. Jacob did a great job on this.

LiveCD?

[grahamsaa]

Not sure how hard this would be to do, but it seems like it would be fairly easy to boot from a livecd/usb key. If you remove packages you don't want the end user to have access to (it's hard to browse the web for test answers if there's no browser installed) that should address at least some of your concerns. An added bonus is that if you need to repurpose the machine, or if it doesn't need to be in test mode all the time, a simple reboot could restore it to a vanilla version of the OS.

Chortle!

[MrBandersnatch]

Pull out the Ethernet connection. TADA!

Re:Chortle!

[viperidaenz]

or turn the power off to the switch. turn it back on when the test is over to upload the results. or lock down the users accounts via the internet proxy for the time the test is running. You'll then be able to see who tried to cheat by looking at the proxy logs

Re:Chortle!

[wierd_w]

Or simply don't expose it to the internet.

Or, if it really needs to talk to the internet for some very special reason, put it behind a very configurable gateway.

Block all traffic types except port 80 http, and then restrict which ip addresses inbound packets can come from. Tada. Can't use google. Instant 404 error.

This won't stop them from playing uhrkan masters using the .deb they smuggled in, assuming they have the user rights to install. (Failing that they could smuggle in a binary blob version) but it would help prevent cheating.

What I had always considered to be ideal for a kiosk system where you don't want users pwning your workstations is to use a minimalist boot kernel on a usb stick, have the workstation tftp a system image to ram, then boot that.

This would make maintenance as easy as turning the system off, and on again, and would centralize maintenance of the system image.

Initial bootup network activity would spike with all the clients pulling the ramdisk volumes, but you could make the actual kiosk as naked as you wanted that way. No internal hdd to hide stuff on, no optical drive, and only 1 usb port that needs the key inserted because it is the boot volume.

If you go a bit further, and make sure the ctrl alt f1 seq can't be pressed at the hardware level from the kiosk, even better.

Re:Chortle!

[syousef]

Pull out the Ethernet connection. TADA!

Yep first thing I thought of was disconnect the Internet connection. Pulling each ethernet cable won't do it especially if you have LAN logins, but making the Internet unreachable should be trivial.

Google???

[muphin]

did you even google your question?
http://lmgtfy.com/?q=ubuntu+lockdown

maybe this will help you
http://ubuntuforums.org/showthread.php?t=456549
http://users.telenet.be/mydotcom/howto/linuxkiosk/ubuntu01.htm
http://library.gnome.org/admin/system-admin-guide/stable/menustructure-13.html.en

Re:Google???

[obarthelemy]

1st result is for Ubuntu 7.4, might be irrelevant by now.
2nd rseults starts with "modify the BIOS? then install from scratch", which he/she cleary rules out
3rd results is about tweaking menus in gnome, which is not even Ubuntu's desktop anymore.

Unluckily, the exams in question will probably not all be about Linux, so Google might actually be able to find relevant info ^^

Just use Unity.

[Anonymous Coward]

Just use the default Unity desktop bundled with recent Ubuntu releases. It's so fucking unusable in every respect that malicious and benign users alike will want nothing to do with it. They'll use only the Java testing application solely to avoid having to deal with Unity.

You'll never have to worry about them using Facebook, or adding additional users, or installing their own software. Even long-time Unity users have a whole fuck of a lot of trouble doing those things. Many just learn to accept that they never be able to.

Re:Just use Unity.

[PixetaledPikachu]

Even long-time Unity users have a whole fuck of a lot of trouble doing those things. Many just learn to accept that they never be able to.

There's no such thing as "long-time unity users"

Re:Just use Unity.

[Lumpy]

yes there is, Anyone that has used unity for more than 1 hour and has not went on a murderous spree because the interface made them go completely insane.

Make the test application enforce Kiosk mode

[alsuren]

I'd suggest having a whitelist of allowed process names that are allowed to be running during the test as that user. If any other programs are running when the program starts, it should not allow the test to be started until those programs are shut down (add a "kill all" button for newbie users). It should also have a watchdog that polls to make sure that the system is still clean. If it finds any unwanted programs, it should give the user 10 seconds to kill them or fail the test (or require a password to ignore this process). If you can do this in the same thread as the testing program, and in such a way that you can't just attach gdb and pause execution while you google the answers, you're onto a winner.

Re:Homework

[elsurexiste]

Hey, asshole. Ever occurred to you that, given clava's high UID, he/she isn't a geek and don't know enough of Linux/technology to do this? Look at how this question was redacted: it's obvious that he/she is not in control of the system, and is looking for some info here, where people with knowledge gather. Just answer the question if you can help and don't be pompous.

Re:Homework

[Anonymous Coward]

WTF Man. Maybe they are a math/english/whatever teacher using some sort automated grading system. Maybe they're a good teacher but bad with computers? But NO! Unless you crafted it yourself bit by bit then its tantamount to "cheating".

Social Solution

[RedLeg]

No Technology required:

1. Announce anyone caught cheating WILL fail the course.

2. Post exactly ONE proctor at the rear of the room. His job is to catch the FIRST cheat.

3. The first cheat should be escorted from the room, and given the following choice: become the proctor and catch another cheat, or fail. If you catch a cheat, you may retake the test and the cheat becomes the proctor with the same choice.

Lather, Rinse, Repeat.

I recommend you film for future entertainment value.

Red

KDE's Kiosk mode

[Krishnoid]

KDE has had a kiosk mode for quite a while, leading me to believe it's quite mature by now. It even has a GUI setup tool.

LTSP

[drinkypoo]

LTSP has support for some lockdown options, and Ubuntu has support for LTSP. It's meant for running classrooms. You can netboot the clients into LTSP when you want to do an exam, and they can run their own install the rest of the time.

Re:It won't matter.

[hedwards]

More or less, probably the easiest way of doing it would be to boot a CDROM and load the home directory over the network if need be. I haven't gotten it figured out, but you can load ISOs directly from disk using GRUB2 if need be.
http://www.panticz.de/MultiBootUSB

Re:so people who cram

[Ethanol-fueled]

Yep, that's the idea. That's how you get so many idiot grads of top-tier schools who cram (or cheat) through ultra-hard tests but still can't use apostrophes correctly while experienced tech-level (Associate's or Military/trade school) employees are cadding complex drawings, using layout software to design and build boards, breadboarding, running Matlab simulations, writing software, and otherwise finding all of the problems that engineering should have found in the design phase.

And from what I've seen, the ability of an engineer is directly proportional to how many books are in the bookshelf in their office or cubicle. Work and life are both open-book, why shouldn't school be? As others have said here, an open book means nothing when the person doesn't know how to apply their knowledge to make sense of it.

Take somebody who only develops Windows applications in C#, give them a book on embedded Linux, and tell them to get to work on the new hardware widget. If they can't "get it" in a reasonable time frame, then it becomes apparent that they don't have the fitness to apply their knowledge.

Don't look at just the computer...

[Red Storm]

If you're worried about a user jumping out of your app and then searching the Internet, and you're in a a testing setting, you should be looking at a wholistic approach.

Your students will break your application, it's only a matter of time. Use other approaches to make this a useless option.

1) Don't allow any Internet access from the network layer, at all, this includes DNS servers. Ideally your systems should be on a completely disconnected network, meaning there are absolutely no external network connections.

2) Use SELinux to lock down your system. SELinux uses a mandatory permissions model, meaning you *must* be granted permission to be able to do anything.

3) Lock down alternative means of cheating. Cell phones, paper notes and so forth.

4) Follow through with punishing cheating in an appropriate manner.

5) Listen to the feedback of your users (Instructors and Students). This may seem counter intuitive, but it can help you build a better system.

Re:Homework

[obarthelemy]

you forgot: "and design a new test every year, for each class, and different from all tests ever put out by the tens of thousands of universities over the years, coz those will end up on the interwebz".

since you're obviously not mediocre, i guess you're volunteering, genius ?

 

Finally - PROFIT.

[tomhudson]

1. Take bribes from other students to be the first one to cheat.
2. Blatantly cheat and get caught.
3. Become the proctor, and ignore everyone now cheating.

Re:Finally - PROFIT.

[RedLeg]

I'm sure it was satirical. ;)

Actually, it was not.

It's a modified version of a time honored traditional technique I learned while serving in the US Army.

If an instructor caught you nodding off in a class, he would wake you up, put a tear gas grenade in your hand and pull the pin. Your primary mission at that point became catching another troop going to sleep so you could pass the grenade.

Amazing what a live grenade in your hand will do to to keep you alert and focused......

Red

turn the problem upside down

[Cobble]

You're looking for a technological solution to a pedagogical problem. Redesign the questions and let them have all the Internet access they want.

Re:Remove the keyboard

[Richard_J_N]

Actually, an easier way to fix this (that will go away on reboot) is:
1. Student logs in as normal, opens the test app.
2. You SSH in and kill -9 the window-manager.
3. Result: your test app is running full-screen, and there is no way to exit.

To restart the WM, you would need a shell, or Alt-F2 [and the latter is usually a feature of the WM]. There is a neater way to make this all happen if you write a shell-script. Create a desktop startup script that does something like:
    #!/bin/bash
    killall -9 gnome-panel
    killall -9 metacity
    while : ; do java-test-app; done

Then shut down the machine afterwards using Alt-SysRQ-{R,S,E,I,U,B}

Re:WTF? Isn't this super easy in Linux?

[hawguy]

Am I - 13 year long Linux user - missing something here, or isn't it that simple? ... I'm kinda weary, since no one else yet offered that sort of answer.
Please enlighten me if I'm mistaken.

The only thing you're missing is the submitter's requirements:

These computers are used by the students for other purposes and we're not allowed to create special users or change the OS configuration.

It's also likely that the submitter is not technically savvy enough to configure or alter the source code of his Window Manager enough to lock it down securely.

Good option: Fluxbox + browser 'lock-down'

[B5_geek]

0) install Fluxbox
1) edit the keys file and remove the right-click option (disable the other hotkeys too)
2) have firefox set to launch at startup
3) use the firefox addon 'Kiosk mode' and edit settings

That should protect you against most undesired activity.

Re:Setup A VM?

[c 0xFF]

You run the VM in another VM, of course.

VMception, it's VM's all the way down, and all that.

MOD PARENT UP

[Rutulian]

Seriously, this is the best answer I have read here so far. It is simple and elegant. No booting custom images, whitelisting sites, or any of that.

Also, gotta love that half of the answers are: just give a different test, who cares about cheating, just install a different operating system, just fail anyone who cheats, yada yada yada. Why do so many Slashdotters always feel like the best answer to a question is "you're doing it wrong"? Sheesh.

Re:MOD PARENT UP

[germansausage]

"Why do so many Slashdotters always feel like the best answer to a question is "you're doing it wrong"?"

This happens everywhere on the internets where you ask a question. Ask a Microsoft support website how to do something that "should" be possible, but isn't. (Can't think of an example now) You'll get 10 answers telling you how to "work around" what you asked, and another 20 answers questioning why you or any one else would want to do this thing. What you will never ever get is even 1 person saying "Our product cannot do this thing".

Requires things he said he couldn't do

[pavon]

This is exactly the solution I would have proposed, except it goes against the users requirements.

Disabling TTY access requires changes to the OS configuration which he is not allowed to make. Furthermore in Ubuntu, you can't just kill the current X session and start a new one from the command line with the application as the window manager, because it will helpfully restart X when it crashes (or is intentionally killed). You would either need to create a special user whose default WM is the application you want to run, or you would need to reconfigure the OS graphical login settings, neither of which he is allowed to do.

User applications are intentionally prevented from locking down a machine, otherwise any old piece of malware could do so. The only way to really lock it down to modify the OS configuration. That is why all the other answers are suggesting round-about ways to achieve the same goal. IMHO adamdoyle's is the best.

Re:Requires things he said he couldn't do

[jrumney]

Furthermore in Ubuntu, you can't just kill the current X session and start a new one from the command line with the application as the window manager.

Why not?

sudo service gdm stop; Xorg -sp security.policy & kiosk-mode-test-program

Probably if you spend more than the two seconds I did thinking about this you can find a more robust version perhaps involving a custom gdm configuration that can restart the X server if the user logs out prematurely etc.

Re:Requires things he said he couldn't do

[Gunstick]

If I start an X server on display :1 it runs along the :0 instance. No need to do anything to the OS. And if that X server has ctrl-alt-F disabled, well then that's quite well locked up.

http://ubuntuforums.org/showthread.php?t=776098
combined with
startx -config your-kiosk-xorg.conf -- :1

yeah, I didn't test it, don't want to lock up my office PC :-)

Re:Better idea

[icebraining]

I do not carry such information in my mind since it is readily available in books. ...The value of a college education is not the learning of many facts but the training of the mind to think.

-- Albert Einstein

Was he a slacker too?

Time spent memorizing stuff is time that could be better used understanding it. Having no access to reference material is a ridiculous limitation.

Silly.

[sidragon.net]

Look at this photograph. It depicts Einstein working with various equations.

Do you suppose he knew what the operators did? That he knew differentiation and integration rules? That he knew algebra? Or are you suggesting that he went back to his 101 textbooks at every step.

It is the most absurd thing to use Einstein to defend willful ignorance.

Yes, you do actually have to know stuff to learn how to think, guide your intuition, solve problems efficiently, and discuss topics intelligently. Get over it. Learning and understanding takes work beyond typing your query into Google or Alpha.

Re:Silly.

[geminidomino]

It is the most absurd thing to use Einstein to defend willful ignorance.

Only marginally moreso than claiming that decrying "rote memorization" is "defending willful ignorance."

Someone asked this on StackOverflow a while back

[KeithIrwin]

Someone asked a very similar question on Stack Overflow. It's here. The short version is: if you're running KDE and can change the window manager configuration, no problem. If you can change which window manager, then sure. (Also, the previous "yank the ethernet cable" or "boot off of live CD/USB" suggestions are quite reasonable. However, it is possible to handle most of it in the application using JNI to write X-Windows code which will capture most all keystrokes. It doesn't get ctrl-alt-backspace, but it appears to get prevent most of the rest.

Re:Better idea

[SessionExpired]

I do not carry such information in my mind since it is readily available in books. ...The value of a college education is not the learning of many facts but the training of the mind to think.

-- Albert Einstein

Was he a slacker too?

Time spent memorizing stuff is time that could be better used understanding it. Having no access to reference material is a ridiculous limitation.

How did this quote come to you? From memory?

Ubuntu locked down for a school environment

[PhilipJLewis]

I worked on this project for a Primary school. It's worked well for >2 years for 120 pupils.
http://linuxcentre.net/wiki/
The parts about automatically resetting the homedir after reboot is probably of interest to you.
http://linuxcentre.net/wiki/index.php/Detailed_Maverick_Meerkat_OS_Netbook_Customisation below Home_Directory_Synchronisation

We had this at my university

[Ed Avis]

I studied computing at Imperial College London and there was such a setup for lab exams. It would lock down the Linux machine so you couldn't communicate with the Internet or with other computers in the lab, but it would communicate with a central server so you could submit your work. You could contact the Department of Computing to ask if they still have this system and if they would share it.