Mailinglist Archive: opensuse-edu (194 mails)

[Thomas Adam <thomas_adam16@xxxxxxxxx>]

 --- Martin Orr <martin@xxxxxxxxxxxxxxxxxx> wrote: 

> On Mon, Jul 28, 2003 at 10:33:34AM +0100, Thomas Adam wrote:
> >  --- Peter Wilson <peter.wilson@xxxxxxxxxx> wrote: 
> > 
> > > As far as my understanding of the philosophy of su is concerned, the
> > > default action is not to perform a 'login' but to change the
> effective
> > > guid and uid of the shell, this is the function of the '-' or '-l'
> > 
> > Yes, you are right when you say that a normal "su" changes the
> effective
> > UID **and** GID, but that is only for the $USER, and NOT for the shell
> as
> > you write above :) the shell does not have U{G}ID's!!!
> 
> Of course the shell has UID and GIDs.  The shell is a process and every
> process has real, effective, saved and (on Linux) filesystem UIDs and
> GIDs which determine which files it can access and how it can interact
> with
> other processes.  It makes no difference how you call su however - they
> will
> all be set to 0.  (If you want to see these values, "cat
> /proc/$PID/status |
> grep Uid" will give them to you.)

:) *cough*, /bin/bash does not have a GID/UID assigned to it per se, which
is now I interpreted Peter's initial sentence. /bin/bash (or whatever
$SHELL is set to) is not the one that handles the U{G}ID's at all, that is
done with the kernel (as you have spotted via "/proc"). Again, you're
slightly in error as "su" is specified by "su [user]" will change the
GID/UID for the [user] specified, and will NOT get changed to 0.

-- Thomas Adam

=====
Thomas Adam

"The Linux Weekend Mechanic" -- www.linuxgazette.com

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