SELinux enforcing disallows opening floppy drive in Nautilus

[Stephen Smalley]

On Thu, 2006-04-13 at 18:35 +0100, Ron Yorston wrote:
> Stephen Smalley <sds at tycho.nsa.gov> wrote:
> >Seems like a policy bug (omission of a transition from unconfined_t to
> >mount_t) to me.  Otherwise, /etc/mtab is going to lose its type every
> >time you run mount/umount from the shell.  Dan?
> 
> Just a clarification (or confusion):  it's only umount that causes the
> problem.  mount doesn't create a new /etc/mtab file and doesn't change
> the context:
> 
>    # ls -Z /etc/mtab
>    -rw-r--r--  root     root     system_u:object_r:etc_runtime_t  /etc/mtab
>    # ls -i /etc/mtab
>    33032 /etc/mtab
>    # mount /opt
>    # ls -Z /etc/mtab
>    -rw-r--r--  root     root     system_u:object_r:etc_runtime_t  /etc/mtab
>    # ls -i /etc/mtab
>    33032 /etc/mtab
>    # 

Ah, ok.  strace of mount and umount suggests that mount just
writes/appends to the existing file in place while umount creates a new
file without the entry and then replaces the original file via rename.
Which would explain why mount doesn't disturb the type but umount does.
Regardless, I think it makes sense to have unconfined_t transition to
mount_t.
 
-- 
Stephen Smalley
National Security Agency