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How do I edit an invalid visudo file?

Here is what happens:

$ sudo visudo

>>> /etc/sudoers: syntax error near line 28 <<<
sudo: parse error in /etc/sudoers near line 28
sudo: no valid sudoers sources found, quitting
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2  
great question considering this page creates that error help.ubuntu.com/community/RootSudoTimeout –  user128334 Sep 21 '13 at 18:14

12 Answers 12

up vote 115 down vote accepted
+50

On a modern Ubuntu system (and many other GNU/Linux distributions), fixing a corrupted sudoers file is actually quite easy, and doesn't require rebooting, using a live CD, or physical access to the machine.

To do this via SSH, log in to the machine and run the command pkexec visudo. If you have physical access to the machine, SSH is unnecessary; just open a Terminal window and run that pkexec command.

Assuming you (or some other user) are authorized to run programs as root with PolicyKit, you can enter your password, and then it will run visudo as root, and you can fix your /etc/sudoers.

If you need to edit one of the configuration files in /etc/sudoers.d (which in uncommon in this situation, but possible), use pkexec visudo -f /etc/sudoers.d/filename.

If you have a related situation where you have to perform additional system administration commands as root to fix the problem (also uncommon in this circumstance, but common in others), you can start an interactive root shell with pkexec bash. Generally speaking, any non-graphical command you'd run with sudo can be run with pkexec instead.

(If there is more than one user account on the system authorized to run programs as root with PolicyKit, then for any of those actions, you'll be asked to select which one you want to use, before being asked for your password.)


If that doesn't work--for example, if there are no users authorized to run programs as root via PolicyKit--then boot from an Ubuntu live CD (like the CD you probably used to install Ubuntu) and mount the filesystem for the installed system. You can do this by running sudo parted -l to view your partitions--there is probably just one ext4 partition, and that's the root filesystem.

Suppose the installed Ubuntu system's root filesystem is on /dev/sda1. Then you could mount it with sudo mount /dev/sda1 /mnt. Then you can edit the installed system's sudoers file with sudo nano -w /mnt/etc/sudoers. Or, even better, you can edit it with

sudo visudo -f /mnt/etc/sudoers

(which will prevent you from saving a sudoers file with incorrect syntax).

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2  
pkexec /usr/sbin/visudo worked on debian 7 –  marinara Mar 5 at 1:33
    
Couldn't they also just boot into recovery mode? –  Seth Oct 11 at 16:43

if anyone else like me didn't have pkexec installed, or was not able to run vi, visudo, nano or any other editor to change sudoers file you can be sure with this process.. I was saved with this:

  • reboot
  • hold shift key while booting to have option for recovery mode (enter it)
  • enter command line as root (second last option at my grub menu)
  • remount boot device for rw, and apply exec right for user, and edit file
    • mount -n -o remount,rw /
    • chmod u+x /etc/sudoers
    • nano /etc/sudoers

fix that mistake and be happy :)

cheers, krex

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pkexec visudo

then revert your mistakes

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1  
not necessary to use pkexec –  Braiam Jan 1 at 12:01
    
@Braiam visudo has to be run as root. If sudo doesn't work, pkexec sometimes does. This is covered by my earlier answer... but it is a correct answer, visudo by itself (when not run as root) will not work, and there may be value in correct, brief answers even when their recommendations overlap considerably with other answers. Of course, if one goes into recovery mode, that's a root shell and then neither sudo nor visudo is necessary for commands like pkexec. Maybe that's what you mean... –  Eliah Kagan Mar 29 at 5:30

You can also login as root on a tty console with Ctrl+Fn (Fn from 1 to 6) and run visudo.

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Type in:

pkexec visudo

Then change last line

includedir /etc/sudoers

To:

includedir /etc/sudoers.d

It should solve your problem.

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I've noticed that removing the leading # from #includedir causes syntax errors, the # is part of the directive, at least on Ubuntu 12.10. –  SAFX Apr 5 '13 at 2:46

You can edit your boot entry while in grub as well.

Simply reboot your pc, and wait for grub to show. Then press "e" on the "Ubuntu" entry to edit it.

Look for a line with "linux = " or "kernel = " and simply add an "single" to the end of that line.

Then press F10 to boot this temporarily modified boot entry. This will give you a shell (without GUI) with root rights and you can edit the sudoers file with s.th. like nano /etc/sudoers back to its previous state.

Then reboot and its done.

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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

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check permissions of root system /. it must be owned by root und use 755, than find command of sudo will find the config.

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What does "than find command of sudo will find the config" mean? –  Eliah Kagan Mar 29 at 17:45

There is nothing wrong #include sudoer.d removing #include sudoer.d won't make any difference.

But please make sure you don't have any syntax errors. I had same issue but and spent hours to fix and just figured out they are syntax errors. Refer to manual and make them right.

For example Say your username is : dolly I used following which is wrong

 dolly ALL = (ALL) ALL NO PASSWD: ALL

correct syntax is

dolly ALL = (ALL) ALL //give permission to everything, not good

or

dolly ALL=(ALL) NOPASSWD:/usr/bin/thurderbird //good, give specific permission

hope this helps

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A better approach than making sure you don't have syntax errors is to always use visudo when editing these files, which makes sure you don't have syntax errors for you, before it modifies file. visudo is not just for editing /etc/sudoers--it will also create and edit files in /etc/sudoers.d. It will also work with whatever text editor you want. See the manpage for details. –  Eliah Kagan Jul 3 '12 at 0:12
    
As for giving specific permission, please note that this is only useful for very simple commands/apps, because any sufficiently complex app (including thunderbird, which should never be run as root anyway) will effectively give the user full system access when run as root. Even seemingly simple functionality opens the door to full root access. For example, a user who can run a program that can save a file to an arbitrary location as root can gain full root access (they can install their own /etc/sudoers, or if syntax limitations prevent that, they can install their own /etc/crontab). –  Eliah Kagan Jul 3 '12 at 0:16

Always use visudo to edit your sudoers file, never edit it directly yourself. It will prevent you saving it to disk unless it validates.

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I found the bug. It is in the last two lines of the default /etc/sudoers file. Remove the following entries from the end of the /etc/sudoers file with visudo.

#includedir /etc/sudoers.d
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1  
That seems like a related, but different situation from this one. In this situation, the problem isn't that there are bad files (or wrong permissions) in /etc/sudoers.d, but that /etc/sudoers was itself corrupt. –  Eliah Kagan May 29 '12 at 6:32

run recovery mode then type this

chown -R root:root /etc/sudoers.d
chmod u=rwx,g=rx,o=rx /etc/sudoers.d/
chmod u=r,g=r,o= /etc/sudoers.d/*

only the group and user root should have read privelege

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protected by Braiam Mar 7 at 23:50

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