If I choose not to have a password for my operating account, every operation fails if it needs root access. Reproducible even on a newly set up machine. See: http://ubuntuforums.org/showthread.php?t=1862543
Cause: The password is cleared to be empty, and this prevents authentification for many admin tasks for security reasons. However, the user only needs to be added to the "nopasswdlogin" group, to enable passwordless login with gdm (and any other DM that ships with a corresponding "auth sufficient pam_succeed_if.so user ingroup nopasswdlogin" configuration).
* lightdm to add pam rule
* account managing tools not clearing password but only adding user to
Steps to reproduce:
1. Install Ubuntu 11.10 as normal. During installation, when you are asked to choose a password, enter one, since the installation can not continue if you do not do so.
2. Boot the newly installed system and log in as usual.
3. Choose "System Settings" from the launcher on the left and open "User Accounts".
4. In the User Accounts window, click on Unlock at the top right of the dialog. Enter your user password when prompted.
5. Click on the four dots next to the "Password" label to change your password.
6. Select "Log in without a password" from the dropdown box. Close the window.
7. Try to perform an action requiring administrative privileges. For example, try running "sudo apt-get update" from a terminal.
sudo should require the user's password and accept it, or proceed without requiring any password altogether.
sudo requires the user's password and does not accept it (since it is set to an empty string in /etc/shadow).
After disabling the password request at login, the /etc/shadow file related to the test user account I created looked like this:
This shows that the password hash is made completely empty; that conflicts with the policies listed in /etc/sudoers, which require a password to be given in order to perform
-If you can not perform administrative actions but can still login without a password, open a terminal and type "passwd". This command should prompt you for a new password and change it without any problems.
-If you can not login, you can reset your password by booting into recovery mode and changing it there. Follow the instructions at <http://psychocats.net/ubuntu/resetpassword>.
You may also choose to use a password for your account and to enable autologin at the same time. This choice will enable you to benefit the advantage of not entering a password at boot time with the security of Ubuntu requiring your password when attempting to perform privileged actions. Of course, this helps when you are the only desktop user or the primary one.