Messed up sudo in Ubuntu

scandalist · 05-10-2012, 12:18 AM

Greetings,

I just installed Ubuntu on an old laptop and began the process of creating a user account for me and my girlfriend. Apparently Ubuntu doesn't come with a root password and ships instead with one standard account with sudo privileges.

I needed sudo privileges for my account as well so I edited /etc/group and added my username to the admin group. I fudged the line and left out the trailing colon that should be at the end of the entries - This has rendered the system useless when trying to do anything privileged because neither accounts have access to sudo anymore...lol.

Is there a way to fix this?? Thank you!

yars · 05-10-2012, 12:38 AM

Hi, I think it is following steps:
Boot any LiveCD/DVD/FlashDrive, then:

Code:

# mkdir -pv /mnt/ubuntu
# mount /dev/sda5 /mnt/ubuntu
# nano /mnt/ubuntu/etc/group
# nano /mnt/ubuntu/etc/sudoers

Where are /dev/sda5 is a partition with your rootfs.

TobiSGD · 05-10-2012, 05:45 AM

Like yars said. For future use, if you use commands like usermod and visudo you don't have to edit the configuration files manually and can't mess up the system with typos.

TroN-0074 · 05-10-2012, 06:08 AM

you can type a combinations of commands and that would work too.
something like

Code:

sudo su

Or you can use the users and group tool on the GUI

Good luck to you!

yars · 05-10-2012, 08:35 AM

Quote:

Originally Posted by TobiSGD

Like yars said. For future use, if you use commands like usermod and visudo you don't have to edit the configuration files manually and can't mess up the system with typos.

+1. In addition, it is as far as I know, blocking access to files at the time of your experiences with them, that positively affects your safety.

Erfankam · 05-10-2012, 04:15 PM

Yah. You are right. By default, your account has not sufficient privilege to execute administrative command like that.
In first step we can activate root account by setting up a password:

Code:

sudo passwd root

If you cant do this, we can edit suduers file at "sudo vi /etc/sudoers" location:

Code:

<your_username>    ALL=(ALL:ALL) ALL

after adding this line and save file,
again execute this:

Code:

sudo passwd root

after setting password up, you can use su to login as a root user to do what you would.
If not, Just add your username like up to sudoers file to be able execute any command(ALL) by sudo in your normal user.

TobiSGD · 05-10-2012, 04:59 PM

Quote:

Originally Posted by Erfankam

Yah. You are right. By default, your account has not sufficient privilege to execute administrative command like that.
In first step we can activate root account by setting up a password:

Code:

sudo passwd root

If you cant do this, we can edit suduers file at "sudo vi /etc/sudoers" location:

Code:

<your_username>    ALL=(ALL:ALL) ALL

If the user can't run sudo su the he will also not be able to run sudo vi, which is by the way not the recommended way to edit /etc/sudoers, the recommended way is to use visudo.

Erfankam · 05-10-2012, 05:11 PM

Quote:

Originally Posted by TobiSGD

If the user can't run sudo su the he will also not be able to run sudo vi, which is by the way not the recommended way to edit /etc/sudoers, the recommended way is to use visudo.

TobiSGD, Thanks for your notation.
Yah, But sometimes just some of commands in sudoers file is restricted. I think one of them was passwd.
Ok, If Tobi is right and you dont have any access to sudo commands, use a live distro to boot up and edit sudoers file by that to add all commands to it like up.