RE: group membership activation

[Bonno Bloksma]

Hi Seeker,

>> Running a fresh Jessie install on a laptop with GNOME.
>> Today I had to add a user (me) to a group (wireshark) for a program 
>> (wireshark gui) to work. At first I thought I did something wrong but 
>> after a reboot it did work, wireshark was able to see the interfaces.
>>
>>[...]
>> I know that in a Windows environment the group membership is added to 
>> the user token at login. Changes in group membership have no effect 
>> untill the user logs in again.
>>
> If you know enough to know that about Windows, I don't know why you would 
> assume there was a problem or that you did something wrong in Linux.
> 
> It's not a problem, it's by design.
> 
> Mysteriously the first things that come up for me on google don't mention 
> it

Which is what I ran into as well. I do not remember what I used as search 
keys(s) but my first 4-5 hits did not provide an answer, which is why I asked.
Thanks for your pointers as well.

Bonno Bloksma

Re: group membership activation

[Celejar]

On Thu, 18 Feb 2016 16:10:48 +
Bonno Bloksma  wrote:

> Hi,
> 
> Running a fresh Jessie install on a laptop with GNOME.
> Today I had to add a user (me) to a group (wireshark) for a program 
> (wireshark gui) to work. At first I thought I did something wrong but after a 
> reboot it did work, wireshark was able to see the interfaces.
> 
> So probably group membership is not determined at runtime but maybe at login 
> or some other moment. Where can I find more info about this? 
> Is this a problem specific to a desktop environment of can I run into this 
> with a straight CLI setup as well?
> 
> I know that in a Windows environment the group membership is added to the 
> user token at login. Changes in group membership have no effect untill the 
> user logs in again.

IIUC, Linux works the same way, although there are workarounds:

http://superuser.com/questions/272061/reload-a-linux-users-group-assignments-without-logging-out
https://arkaitzj.wordpress.com/2010/03/08/linux-add-user-to-a-group-without-logout/

> Bonno Bloksma

Celejar

Re: group membership activation

[Seeker]

On 2/18/2016 8:10 AM, Bonno Bloksma wrote:

Hi,

Running a fresh Jessie install on a laptop with GNOME.
Today I had to add a user (me) to a group (wireshark) for a program 
(wireshark gui) to work. At first I thought I did something wrong but 
after a reboot it did work, wireshark was able to see the interfaces.


So probably group membership is not determined at runtime but maybe at 
login or some other moment. Where can I find more info about this?
Is this a problem specific to a desktop environment of can I run into 
this with a straight CLI setup as well?


I know that in a Windows environment the group membership is added to 
the user token at login. Changes in group membership have no effect 
untill the user logs in again.


Bonno Bloksma

If you know enough to know that about Windows, I don't know why you 
would assume there was a problem

or that you did something wrong in Linux.

It's not a problem, it's by design.

Mysteriously the first things that come up for me on google don't 
mention it


https://www.pluralsight.com/blog/tutorials/linux-add-user-command

http://www.oreilly.com/openbook/debian/book/ch07_01.html

Probably easily overlooked, but the relevant Archwiki page does mention 
that if the user is logged in at the
time the change is made, they will need to log out and log in before 
they see the change.


https://wiki.archlinux.org/index.php/users_and_groups

Later, Seeker