[SOLVED] help with sudoers file

[tarazed]

Trying to find a way to unmount removable media such as USB drives, as a user, I edited /etc/sudoers hoping to run sudo umount without a password.
This fails completely.

Information about the user:

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[lcl@belexeuli ~]$ id lcl
uid=500(lcl) gid=500(live) groups=500(live),100(users)


Entry in /etc/sudoers with template command used as model:

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## Allows members of the users group to shutdown this system
# %users  localhost=/sbin/shutdown -h now
%users localhost=/bin/umount NOPASSWD


Trial:

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[lcl@belexeuli ~]$ sudo umount /run/media/lcl/Sirius
[sudo] password for lcl:
lcl is not in the sudoers file.  This incident will be reported.


I am stumped. ??

[maat]

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%users  ALL=    NOPASSWD: /bin/umount


Take care of having a [TAB] afer %users and an other before the NOPASSWD

Please also note that sudo controls the options you give to commands so you could be able to run /bin/umount but not /bin/umount /mnt/cdrom (I did not check)

[tarazed]

Thanks maat. I used that command but came up with the same request for lcl's password and the same error message.
Meanwhile I had created the group lcl and tried to make it the primary group, first in mcc manage users -> failed to change it from live, then using

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 usermod -g lcl -G lcl,live,users lcl

That failed too. So how do I get sudoers to recognize lcl as a user? Does ALL have to be configured?

[maat]

done :
1/ create a group

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# groupadd mygroup


2/ defined my user as in the group

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# vi /etc/group


And added my user "maat" to "mygroup":

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mygroup:x:503:maat


3/ Then changed my sudoers file:

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# visudo


Modified the file (and saved with :wq):

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%mygroup  ALL=    NOPASSWD: /bin/umount


4/ Switched to my user maat and tested umount :

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# su - maat
$ sudo umount
Utilisation : umount -h | -V
       umount -a [-d] [-f] [-r] [-n] [-v] [-t typevfs] [-O opts]
       umount [-d] [-f] [-r] [-n] [-v] spécial | nœud...


worked perfectly

[tarazed]

I had effectively done all that. I am wondering if I need to logout and back in again for these changes to be properly registered.
I'll be back...

[tarazed]

No, that had no effect.
Directory listings still show live as the primary group.
I have these three entries in /etc/group:
users:x:100:lcl
live:x:500:lcl
lcl:x:500:lcl

A clash?

[maat]

mygroup was not primary in my test

the primary group is defined in /etc/passwd

So your problem does not come from wether users is primary or not

[maat]

i re-tested with %users (gid 100) and the problem triggers

so the problem is linked to %users (group id = 100 too low ?)

Please test with a new group %localusers

[maat]

Deeper answer : users is disabled as a group by default.

If you REALLY want to use it for sudo you have to edit /etc/gshadow and put a ! like this :

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users:!::


My advice is : DO NOT PLAY WITH THAT (unless you really really know what you do)

=> Create another group will be safer and cleaner

[tarazed]

All new information. Thanks.

Set up localusers as GID=501 and added lcl to that group,
changed live to GID=502,
removed lcl from the users group.

Replaced %users by %localusers in sudoers and bingo, it worked, and ownership of my files comes out as lcl:lcl.

Len

[maat]

you're welcome

=> Now please edit your first post and add [SOLVED] at the beginning of the title... that will help other members to know this is solved (helpful for those in search of a solution and helpful for helpers team to concentrate on unsolved problems)

Thank you

[doktor5000]

FWIW, actually unmounting of removable drives should work, as you seem to have it mounted via your desktop environment. If it doesn't work, please give some information which desktop environment you're using and how you mounted those removable drives.