Reset of master password

[52ROSt]

LM 20.2 Cinnamon

I needed to have the motherboard replaced. For having this done, the master password was changed, but not be me.

Now don't laugh!

The "changer" of the master password forgot the new password and the changer of the motherboard forgot it as well.

Is there a chance to reset the current master password without reinstalling LM completely new? (The PC is tweaked a lot!)

Thanks for helping replies.

[xenopeek]

Depends on what you mean with "master password". Do you mean:
1. the password of your primary Linux Mint account, the one with administrator privileges
2. the root account (username: root), which is not enabled normally on Linux Mint
3. the disk encryption mount passphrase that you need to enter before Linux Mint boots
4. or perhaps BIOS password?

[52ROSt]

@ xenopeek

Thanks for reply and detailed questions.

It is the password of my primary Linux Mint account, the one with administrator privileges.

[xenopeek]

Okay. The below can be used to reset your password, but only if you weren't using any type of disk encryption. If you used full disk encryption or home directory encryption there are more steps to this.

But assuming no disk encryption these are the steps. Power on the computer and hold down or repeatedly press the down arrow key to force the GRUB boot menu to show. Here select to boot recovery mode (I think in advanced boot options). Then select to drop to a root console. If this prompts you for a password, that needs root's password. If it doesn't prompt you for a password or you knew root's password, you'll end up on a full screen terminal (command line interface). Here enter these two commands:

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mount -o remount,rw /
ls /home

The first makes the system writable. It boots in read-only mode by default so this is needed. The second command will show all the usernames on your system. Next run these three commands and replace "username" in the first command with the username as shown in the ls /home output for which you want to reset the password. It's case sensitive so type it exactly as shown in ls /home output.

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passwd username
sync
reboot

The first command will prompt you to enter a new password for the username. The second and third ensure it's written to disk and then reboots the system.

[all41]

Innocuous way--create a new user with root privilege
Follow steps 1 thru 4 here to get to a command line:
https://linuxconfig.org/ubuntu-20-04-re ... t-password
that will display a command prompt.
Then:
1. Add a user named 'me' (can be any name)

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 useradd me

enter
2. Set the password for 'me'

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 passwd me

(can be any password)
enter and verify
3. Make a home directory for 'me'

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mkdir /home/me

enter
4. Take ownership of that directory

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chown me /home/me

enter
5. Set the group for 'me'

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chgrp me /home/me

enter
6. Give user 'me' sudo privilege

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usermod -aG sudo me

enter
7. reboot

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reboot -f

enter

finished--now login as 'me'--password 'me'
'me' user can invoke full root privilege (sudoer)

Use this to enter Users and Groups and make changes there to restore normal login
and/or make other needed changes--
You can delete the 'me' user afterward.

[xenopeek]

Then:
1. Add a user named 'me' (can be any name)

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 useradd me

enter
2. Set the password for 'me'

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 passwd me

(can be any password)
enter and verify
3. Make a home directory for 'me'

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mkdir /home/me

enter
4. Take ownership of that directory

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chown me /home/me

enter
5. Set the group for 'me'

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chgrp me /home/me

enter

Steps 1 through 5 can be replaced by a single adduser me.

[all41]

WOW--that users gets sudo?

[xenopeek]

WOW--that users gets sudo?

No, you still need your step 6 for that. But the adduser command does the same thing as all your lower level commands from your step 1 through 5.

[all41]

WOW--that users gets sudo?

No, you still need your step 6 for that. But the adduser command does the same thing as all your lower level commands from your step 1 through 5.

Got it.
Less typing=less odds of pebkac--
Thanks

[all41]

The opening quote from this link: https://linuxhandbook.com/useradd-vs-adduser/ is enlightening:

Useradd is built-in Linux command that can be found on any Linux system. However, creating new users with this low-level is a tedious task because it doesn't create home directory and user password by default.

Adduser is not a standard Linux command. It’s essentially a Perl script that uses the useradd command in the background. This high-level utility is more efficient in properly creating new users on Linux. It gives you the option to create home directory, set password along with a few more parameters.

Digesting