Re: Names vs. Inodes

From: Serge E. Hallyn (hallynat_private)
Date: Fri Jul 20 2001 - 08:45:36 PDT

  • Next message: Greg KH: "Re: Names vs. Inodes"

    > On Thu, Jul 19, 2001 at 10:15:33PM -0700, Crispin Cowan wrote:
    > > 
    > > SubDomain does not allow confined programs to call mount or umount.  SubDomain's
    > > threat model is only concerned with confined processes and principals external to
    > > the machine.  Unconfined processes don't matter, because there either shouldn't be
    > > any, or they are there for a reason and are trusted.
    > 
    > Ok, so then all SubDomain has to contend with is handling hard links.
    > 
    > But since I know that SubDomain only allows hard (and soft) links if
    > they are specifically listed in a process's profile, no unknown links
    > can be created by a process.
    > 
    > So the inode that is passed to permission() should only have a dentry
    > list containing 1 dentry.  Reconstruct the path from that dentry, and
    > bob's your uncle.
    
    Not at all.  The dentry list is systemwide.  if /dev/mouse is a link to
    /dev/psaux, and the process access /dev/psaux, while another process
    accesses /dev/mouse, the inode has two entries on it's dentry/d_alias
    list.
    
    Now, again, attach_pathlabel does no better, unless you attach multiple
    labels to each inode as I've mentioned previously in private.  Not pretty.
    
    I'm starting to wonder how this was originally implemented...
    
    -serge
    
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