Gnome screensaver lock always reports "incorrect password"

[glass.dimly]

Binary package hint: gnome-screensaver

When inactive, the screensaver locks the workstation. When logging back in, I enter my password. This always returns "incorrect password".

Workaround: hit "Switch User" log in as that same user with the denied password, revealing the session that was logged out of.

I changed the password: "sudo passwd". No change in behavior.

The question: where is it drawing the password from if not from the same place that the regular login derives it? And how can I fix this admittedly small but annoying problem?

[Ed ODonnell (edodonnell)]

What versions of Ubuntu, Gnome, and gnome-screensaver are affected?

[Saramburu (seba2005)]

You can see the solution here: https://bugs.launchpad.net/ubuntu/+bug/299717

SOLUTION:
chown root:shadow /sbin/unix_chkpwd
chmod 2755 /sbin/unix_chkpwd
chown root:shadow /etc/shadow

[Sebastien Bacher (seb128)]

We are closing this bug report as it lacks the information, described in the previous comments, we need to investigate the problem further. However, please reopen it if you can give us the missing information and don't hesitate to submit bug reports in the future.

[JeromeQc (jeromestpierre)]

I am experiencing the exact same issue and Saramburu solution doesn't work for me. It must be because of recent updates since this issue only started today and I was able to unlock my screen many times a day just recently.

This is a major problem for me since I have another bug when I switch sessions causing vertical green lines on my screen. The only workaround is to restart my X session and it made me loose my work setup each time. For now, I unchecked the screensaver option to lock the screen.

This is not related to the screensaver (in my case) because I also get this problem when locking the screen manually from the start menu.

What missing information do you need to be able to solve it? I can reproduce it easily.

I am on Jaunty Jackalope with Gnome 2.26.1.

[Michele Giacomoli (michele-giacomoli)]

It's a bit late XD, but try after Saramburu's commands:

sudo chmod g+r /etc/shadow

It worked for me ;)

[Peter M. (jdoe666)]

Observing same issue on Ubuntu 16.04 (after upgrading from 14.04 where same problem was appearing).

I consider that this effect is also there if you lock the screen manually.
Same workaround works:

- (lock screen manually; re-login says "wrong password"
- try to login as another user with wrong password
- after error, switch back to your user
- now login works

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[flapenguin (flapenguin)]

Same issue on 18.04.

Sometimes, not always, lockscreen starts saying "wrong password".
Currently I'm fixing it via switching to a tty (ctl+alt+f1) and sending SIGTERM to everything that mention screensaver except for gsd-screensaver-proxy (simply via htop interface). After that workaround I'm sometimes stuck with a session that turns off my monitors every 30 seconds of inactivity.

It's really annoying.

[David (david-depowell)]

I have this same issue, started a couple months ago. Everything worked previously. The fixes mentioned above did not help, other than the "switch user and exit X" tip. Must have a regression somewhere because the most recent comment above is 12 years old (I'm running 20.04).