locked myself out of root permissions-authentication doesn't work

Asked by Mark Maline

My log-in password has always been the same for my log-in to Ubuntu 10.04 LTS Lucid Lynx, sudo, and when I get my updates and want to install them.
Well, I created other user groups for the kids and now sudo doesn't recognize my password. I think I locked myself out of "root" permissions! It still works for initial log-in on boot up, but nothing else! Here is the error message I get when I try my password to authenticate my updates:

Failed to run /usr/sbin/synaptic '--hide-main-window' '--non-interactive' '--parent-window-id' '69206053' '-o' 'Synaptic::closeZvt=true' '--progress-str' 'Please wait, this can take some time.' '--finish-str' 'Update is complete' '--set-selections-file' '/tmp/tmpKrE58u' as user root.

The underlying authorization mechanism (sudo) does not allow you to run this program. Contact the system administrator.

go figure. I did reboot the system twice and same thing happens.
Thanks,
 Mark

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Ubuntu sudo Edit question
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Solved by:
Tom Hurd
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Tom Hurd (thurd) said :
#1

Here is a very similar problem:
https://answers.launchpad.net/ubuntu/+question/56256

The /etc/sudoers file contains:
# Members of the admin group may gain root privileges
%admin ALL=(ALL) ALL

So any user that you want to have permissions to run the sudo command, will need to be in the "admin" group.

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Best Tom Hurd (thurd) said :
#2
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Mark Maline (mmaline) said :
#3

Thanks Tom Hurd, that solved my question.

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Mark Maline (mmaline) said :
#4

Thanks everybody!! I fixed it in 5 minutes.
I booted in recovery mode (Ubuntu 10.04) I had to go into "shell" because it wouldn't recognize GRUB for some reason.
I entered GROUPS and I didn't see admin, so I typed in ADDUSER <MYUSERNAME> ADMIN and it asked for my password, so I entered my original password and it worked!!
I then entered sudo -s -H , I entered my original password again and then reboot.
All is well.
Thanks again to Tom and Marco!!!

Revision history for this message
Mark Maline (mmaline) said :
#5

Thanks everybody!! I fixed it in 5 minutes.
I booted in recovery mode (Ubuntu 10.04) I had to go into "shell" because it wouldn't recognize GRUB for some reason.
I entered GROUPS and I didn't see admin, so I typed in ADDUSER <MYUSERNAME> ADMIN and it asked for my password, so I entered my original password and it worked!!
I then entered sudo -s -H , I entered my original password again and then reboot.
All is well.
Thanks again to Tom and Marco!!!