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Evading the Screensaver in the Ubuntu Hoary LiveCD

The Ubuntu 5.04 LiveCD is great, but it has one fatal flaw: the screensaver prompts for a password. Luckily, using the magic of Unix TTYs, you can get around this.

  1. Press Ctrl+Alt+F1 to switch to tty1.
  2. Run "sudo -s" to switch to root, the superuser. Unlike normal sudo commands, you do not have to enter a password for this.
  3. Change the password for the default user "ubuntu" by running "passwd ubuntu." Enter a new password.
  4. Press Ctrl+Alt+F7 to switch back to tty7, where the X server (read: all graphical applications) is running. Enter the new password into the screensaver's lock dialog.
  5. Continue using your computer.

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6 Comments »

Comment by Martey
 
Comment by Elliot
2005-07-20 11:40:03

It looks like this isn't a "fatal" flaw 'cuz, as you note, it can be worked around.

Comment by Martey
2005-07-20 12:05:10

Considering that both that Ubuntu Linux sells itself as being user-friendly (read: not needing to drop down to the terminal) and that the ability to use the LiveCD without installing Ubuntu to your hard drive makes it extremely attractive to people new to Linux, I would argue that it is pretty serious. Consider the circumstances in which I discovered this bug. I was at work, and had loaded the LiveCD on one of the laptops there. I was so excited about the inclusion of Intel Centrino support that I immediately closed the laptop and ran to show one of my colleagues to suggest the possibility of using Ubuntu LiveCDs instead of Knoppix from then on. Imagine my chagrin when I open the laptop and am faced with a login prompt which I do not know the password to.

The reason I wrote this post was because I could not find anything written about it online until I ran across the bug report a few weeks later. This workaround is not particularly obvious; using "su" instead of "sudo -s," for example, will not work.

 
 
Comment by M
2005-08-15 08:12:24

Its a good little trick, just got me out of a tight spot.

Cheers :)

 
Comment by sdb
2005-11-04 18:31:55

Thanks! Just ran into this. Should have thought of ctrl-alt-f1, but didn't until I found your writeup.

The "fix" should either refuse to lock with the default password, or change the default password such that the unlock is trivial (ie, a blank password if the unlock dialog will accept that would be good).

Stupid bugs.

Thanks again for the writeup,

sdb

 
Comment by Kyle
2006-01-22 14:12:49

I just tested the live cd on a old IBM thinkpad I had laying around with a busted hard drive, its really great but I ran into the problem you just described when I shut the lcd monitor off manually, after 4 pages of google I finally found this post, thanks a ton for making this.

-Kyle

 
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