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Recovering root access in Ubuntu - Printable Version

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+---- Thread: Recovering root access in Ubuntu (/showthread.php?tid=4819)

Recovering root access in Ubuntu - Scientomancer - 07-26-2017

Yesterday I had cause to add the ubuntu user to the www-data group. I believe I did this:

Code:
# usermod -G www-data ubuntu

Since then, I am unable to become root. If I try to sudo -i, I am told

Code:
Sorry, user ubuntu is not allowed to execute '/bin/bash' as root on pine64.

This happens no matter what command I try to run. sudo vim /etc/sudoers?


Code:
Sorry, user ubuntu is not allowed to execute '/usr/bin/vim /etc/sudoers' as root on pine64.


I don't actually know if adding ubuntu to a group caused this; it's just the biggest change I've made, and I can't think of anything else I've done that would cause this.

Thanks!

RE: Recovering root access in Ubuntu - MarkHaysHarris777 - 07-26-2017

(07-26-2017, 01:05 PM)Scientomancer Wrote: Yesterday I had cause to add the ubuntu user to the www-data group. I believe I did this:

Code:
# usermod -G www-data ubuntu

Since then, I am unable to become root. If I try to sudo -i, I am told

Code:
Sorry, user ubuntu is not allowed to execute '/bin/bash' as root on pine64.

This happens no matter what command I try to run. sudo vim /etc/sudoers?


Code:
Sorry, user ubuntu is not allowed to execute '/usr/bin/vim /etc/sudoers' as root on pine64.


I don't actually know if adding ubuntu to a group caused this; it's just the biggest change I've made, and I can't think of anything else I've done that would cause this.

Thanks!


hi,   hmmm  not run into anyone trying to do this to themselves before;

... do you really want anyone in the www-data group to also be in the soduers file ?   ... probably not.

While I'm not precisely sure what you have done to yourself, you can undo it by placing the SD card into another linux machine and mounting the ext4 partition containing /rootfs and removing the offending change.

RE: Recovering root access in Ubuntu - pfeerick - 07-26-2017

(07-26-2017, 01:05 PM)Scientomancer Wrote: Yesterday I had cause to add the ubuntu user to the www-data group. I believe I did this:

Code:
# usermod -G www-data ubuntu

Since then, I am unable to become root. If I try to sudo -i, I am told

Code:
Sorry, user ubuntu is not allowed to execute '/bin/bash' as root on pine64.

Unfortunately, you haven't ADDED the ubuntu user to the www-data group, you've REPLACED the ubuntu primary user group with www-data, and consequently removed it from all other groups. For future reference, the command should have been -aG (yes, the a is important!). And because the root account is locked by default, unless you unlocked that, you can't log in as root to re-add ubuntu to the sudo group.

If you have another linux systen handy (or you can download VirtualBox and run a copy of ubuntu in a virtual machine, or make a bootable USB/CD), you could mount the ext4 partition, and edit /etc/groups, and re-add your username to the end. i.e. on my desktop, the sudo group line looks like this for the 'pfeerick' user. So just look for the sudo line, don't change the group number if it is different, and re-add ubuntu to the end. Then unmount, boot it back up, and see if it's fixed Wink

Code:
sudo:x:27:pfeerick


RE: Recovering root access in Ubuntu - Scientomancer - 07-28-2017

I successfully recovered using the method suggested: mounting my system's filesystem on another machine and editing /etc/group. Thanks very much! Sorry that this didn't turn out to be a Pine specific question.