Re: [gentoo-user] KDE and permissions problems

[pk <peterk2@coolmail.se>]

On 2012-03-17 11:19, Dale wrote:

> The program 'su' could not be found.
> Ensure your PATH is set correctly.

What does 'echo $PATH' give you? /bin should be in your path (that's
where 'su' is located, or should be)... My $PATH looks like this:
/usr/local/bin:/usr/bin:/bin:/opt/bin:/usr/x86_64-pc-linux-gnu/gcc-bin/4.5.3:/usr/games/bin

I don't know if this is the case but maybe, you're using some of the
new-fangled screw up'ed tools like, dracut, systemd etc. that wants to
move everything into /usr (on the same partition as /) and as such
changes your $PATH accordingly (without checking perhaps - which would
be consistent with the arrogance of the coders).

> -rws--x--x  1 root root   36680 Mar 16 23:36 su
> -rws--x--x  1 root root   52416 Mar 16 23:19 umount
> -rws--x--x  1 root root   42592 Mar 16 23:36 passwd

The 's' part is for the SetUID bit which gives the root-owned command in
question root privileges, in order to switch user... See:
http://blog.superuser.com/2011/04/22/linux-permissions-demystified/

(esp. the "Getting sticky!" chapter).

That's not all though...:

> it, then what?  I am in the wheel group.  I'm also in the tty group.

Check your /etc/pam.d/su file... it should contain (at least) this line:
auth       required     pam_wheel.so use_uid

That's what gives you permission to use 'su' as a member of the 'wheel'
group ('su' is controlled by 'pam').

Best regards

Peter K