How can I fix broken sudo - sudo: parse error in /etc/sudoers near line 23?

Question

I am getting this error:

sudo: parse error in /etc/sudoers near line 23
sudo: no valid sudoers sources found, quitting
sudo: unable to initialize policy plugin

I was trying to disable password authentication so I don't have to type password every time I want to install something, but I probably changed it in a not very good way. I am a newbie to Ubuntu, I got sick of Windows :)

So far I've found some people suggesting booting in single user mode, but I'm afraid of messing things up more.

How can I fix this error?

If you boot in single user mode and use `visudo`, then it won't let you save an incorrect file, so you will not be able to mess things up further. — nanofarad, Oct 30 '12 at 11:18
Thank you, how do I change the file, then? And, how exactly do I boot in single user mode? — Robert Fáber, Oct 30 '12 at 11:19
Hold Shift immediately while booting so that you get the GRUB screen. Select the recovery mode. Choose to drop to a root terminal. Run `mount -n -o remount,rw /` and then `visudo`. Ctrl+O saves, Ctrl+X exits without saving. It won't let you save a bad file. — nanofarad, Oct 30 '12 at 11:21
@ObsessiveSSOℲ it would be nice to convert the comment to answer and let the questioner to mark it as the best answer. For future - help - others I mean. — NickTux, Oct 30 '12 at 12:14
Deactivating that password switch is about as bad as deactivating UAC on Windows. Every command that tries so call `sudo` internally can do without any problems. You could easily have some software (rootkit) installed without you knowing. I would *strongly* discourage doing this in the first place. — Martin Ueding, Oct 30 '12 at 12:35
I know, I know, it was a huge mistake. Thank you all for your answers. — Robert Fáber, Oct 30 '12 at 22:12
@psusi and close voters: huh? It's a question, with proper answers. It's just missing a "how can I fix this error" sentence, which I've just added. There's no need to close it. — Alaa Ali, Sep 15 '13 at 17:46
@Alaa, it says this is what happened, and this is what I have already been told to do to fix it. That's not a question. — psusi, Sep 15 '13 at 18:26
@psusi when problems are questions? He is asking how to revert it back, and is giving us the history of his actions, he describe his problems, he got [a solution](http://askubuntu.com/questions/209558/how-can-i-fix-broken-sudo-sudo-parse-error-in-etc-sudoers-near-line-23#comment260240_209558). Why close it? — Braiam, Sep 16 '13 at 00:22
@Braiam, because the "solution" is *in* the "question". Without knowing why that isn't acceptable ( besides "I'm afraid" ) it isn't possible to provide a real answer. — psusi, Sep 16 '13 at 01:36
On newer Ubuntu distributions, there's a simple solution (not requiring any reboot nor recovery), described here: http://askubuntu.com/a/73872 — , Aug 28 '14 at 11:23
Isn't there already an answer http://askubuntu.com/questions/73864/how-to-modify-a-invalid-etc-sudoers-file-it-throws-out-an-error-and-not-allowi actually. Just type `pkexec visudo` — xji, Apr 03 '15 at 10:18

score 61 · Answer 1 · edited Apr 13 '17 at 12:25

61

Fixing this is dead simple, and it is answered elsewhere on askubuntu.

Short answer, use:

pkexec editor_of_choice

edited Apr 13 '17 at 12:25

Community

1

answered Nov 25 '15 at 09:39

NeilenMarais

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8
16

2

This is definitely the simplest and best answer. I had no clue pkexec existed. Thanks a lot both – Bizmate Apr 14 '16 at 17:05
4

When I do pkexec, it gives list of users to authenticate. When I type password, it gives Authentication failure. Please help. – Shyamkkhadka May 24 '18 at 05:44
5

@Shyamkkhadka I ran into this also. [This solution on GitHub](https://github.com/NixOS/nixpkgs/issues/18012#issuecomment-335350903) saved me and about a hundred other people. – gillytech Feb 19 '20 at 18:49
This didnt work for me with an error " No session for cookie " but I did this in two terminals: In the first terminal run the following command to get its PID. echo $$ In the second terminal run pkttyagent --process PID_FROM_STEP_1 Then you can run "sudo pico /etc/sudoers" or whatever you want in first terminal, and the second terminal will ask for user password. and will work – DefToneR May 04 '21 at 21:08
thx, useful compare to reboot in recovery mode red-tape procedures... https://stackoverflow.com/a/58195402/3806250 and https://stackoverflow.com/a/58199760/3806250 – Rγσ ξηg Lιαη Ημ 雷欧 Jan 14 '22 at 18:36

nanofarad · Answer 2 · 2012-11-03T09:37:22.033

19

Hold Shift immediately while booting so that you get the GRUB screen. Select the recovery mode. Choose to drop to a root terminal. Run mount -n -o remount,rw / and then visudo. It'll let you fix your problems with the file and save. It won't let you save a malformed file.

edited Nov 03 '12 at 09:37

answered Oct 30 '12 at 12:41

nanofarad

20,597
12
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Shift didn't work for me, I had be pressing keys to get grub – nafg Nov 19 '13 at 06:13
@nafg Every configuration is different. – nanofarad Nov 19 '13 at 11:17
I don't have visudo installed in my ubuntu. What can I do ? – Shyamkkhadka May 24 '18 at 05:45
In Ubuntu 16.04, "Drop to Root terminal" asks for root password (which obviously will not work, because /etc/sudoers is broken). Pressing Ctrl+D will just bring you back to the GRUB screen. – Juha Untinen Aug 14 '18 at 09:26
Thank you so much, I'm glad I know about dropping to a root terminal now, that's very useful. – Matthew Feb 16 '20 at 00:45

score 3 · Answer 3 · edited Sep 15 '13 at 16:52

Folowing solution is for remote servers, it works!

http://ubuntuforums.org/showthread.php?t=2036382&p=12144840#post12144840

then just use visudo to add wheel, etc

Rename your current file

mv /etc/sudoers{,.bak}

Create a new one vi /etc/sudoers with the following basic content:

# /etc/sudoers
#
# This file MUST be edited with the 'visudo' command as root.
#
# See the man page for details on how to write a sudoers file.
# Defaults    env_reset
# Host alias specification
# User alias specification
# Cmnd alias specification
# User privilege specification
root    ALL=(ALL) ALL
# Allow members of group sudo to execute any command after they have
# provided their password
# (Note that later entries override this, so you might need to move
# it further down)
%sudo ALL=(ALL) ALL
#
#includedir /etc/sudoers.d
# Members of the admin group may gain root privileges
%admin ALL=(ALL) ALL

Run visudo and add your custom stuff.

how to move it without sudo and sudo is broken? – Ewoks Jul 27 '20 at 12:42 — Ewoks, Jul 27 '20 at 12:42

score 2 · Answer 4 · answered Dec 14 '12 at 11:03

2

If u messed up your sudoers file.You'll need to:

Reboot into recovery mode (hit escape during boot, choose the recovery mode option on the grub screen)
Choose the 'Enable networking' option (if you don't your filesystem will be mounted as read-only. who knew)
Chosee the 'Drop to root shell' option
run visudo, fix your file
Reboot with normal grub option

source :- http://mario.net.au/content/recover-etcsudoers-ubuntu-1204

answered Dec 14 '12 at 11:03

streak

269
2
5

1

Follow up question: When I choose the `Enable networking` option, I'm prompted to tell the system that I'm sure. I do that and I just drop into nothing. No root prompt, nothing. What should I expect to see/do after the 2nd step? Thanks. – Rob Wilkerson Jan 23 '13 at 14:25

score 2 · Answer 5 · answered Jul 03 '14 at 09:41

2

You can do this:

Create a copy

cp /etc/sudoers /etc/sudoers.bak

Edit problem parts there

vim /etc/sudoers.bak

Replace the origin sudoers file

cp /etc/sudoers.bak /etc/sudoers

It works for me.

answered Jul 03 '14 at 09:41

ajile

144
4

It worked when i logged in using super user (su -) and executed above steps.. Thanks – Dave Oct 13 '14 at 06:15
30

But you need to be root. so... – thomas-peter Nov 22 '14 at 09:46

score 1 · Answer 6 · answered Jul 01 '15 at 15:22

1

I screwed up the sudoers file to find out that I don't remember the root password. Solution: rebooted under Windows (I have a dual boot) and edited the file using ext2fsd (you have to reboot after the installation). In principle, this could be another Linux or a live flash, not necessarily Windows.

answered Jul 01 '15 at 15:22

18446744073709551615

489
1
6
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A lot of people dual-boot Windows and Ubuntu, so this is a solid approach! I know been a while since you've posted this answer... but might you be willing to [edit] this to expand it with detailed information about specifically how to set up and use ext2fsd for this purpose? – Eliah Kagan Jan 09 '17 at 01:29

How can I fix broken sudo - sudo: parse error in /etc/sudoers near line 23?

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