[TUHS] Additional groups and additional directory permissions

[Thomas Paulsen]

thanks a lot!

--- Ursprüngliche Nachricht ---
Von: Kirk McKusick <mckusick at mckusick.com>
Datum: 10.08.2019 06:02:51
An: Clem Cole <clemc at ccc.com>
Betreff: Re: [TUHS] Additional groups and additional directory permissions

>
> Late to answer...
>
> As far as I remember, Clem's description is correct. The filesystem
> itself stores only one owner and one group ID. When checking access
> to the file, the file owner is checked to see if the user ID matches.
> If so, then the owner permissions are applied. If not then the group
> array associated with the user is used to decide if the group of the
> file matches one of the groups of which the user is a member and if
> so the group permissions apply. Otherwise the other permissions are
> used.
>
> In BSD, the group assigned to the file is assigned from the group of
> the directory in which it is created. The setgid flag can be set only
> if that group is a member of the user's group array. The user can only
> change the group ID to one that appears in their group array.
>
> Until multiple group sets were added to System V, the group of the
> file was taken from the gid assigned to the user at login.
>
> 	Kirk McKusick
>