Re: About /etc/mtab and /proc/mounts

Måns Rullgård
2003-02-26T13:44:34Z

Olaf Dietsche <olaf.dietsche@t-online.de> writes:

> >> The 'user' option is in /etc/fstab, so this is not a problem. I can
> >> mount _and_ umount /cdrom as a simple user.
> >
> > It's strange if you can. My mount (fairly recent) looks in fstab to
> > determine whether a user should be allowed to mount a device.
> > However, when unmounting it checks /etc/mtab to make sure it was you
> > who mounted it in the first place, making it impossible to unmount
> > someone else's cdrom. If you use the 'users' (note the 's') option
> > instead any user can mount or unmount the device at any time, mtab
> > being ignored.
>
> I just verified it. I and anybody else can mount and umount /cdrom. If
> I mounted /cdrom, someone else can umount it.
>
> $ mount -V
> mount: mount-2.11n
>
> $ grep user /etc/fstab
> /dev/hdb/0 /cdrom iso9660 defaults,ro,unhide,user,noauto,noexec,nosuid 0 2
>
> $ ls -l /etc/mtab
> lrwxrwxrwx 1 root root 12 2002-09-22 02:58 /etc/mtab -> /proc/mounts
>
> When /etc/mtab is a regular file, it works as you described.

What does your /proc/mounts look like when the cdrom is mounted? Are
you using a standard mount, or something hacked up by RH or others?

--
Måns Rullgård
mru@users.sf.net