[PATCH] fs/vfs/security: pass last path component to LSM on inode creation

[Eric Paris]

On Thu, 2010-12-09 at 12:48 -0500, John Stoffel wrote:
> >>>>> "Eric" == Eric Paris <eparis at redhat.com> writes:
> 
> Eric> On Thu, 2010-12-09 at 10:05 -0500, John Stoffel wrote:
> >> >>>>> "Eric" == Eric Paris <eparis at redhat.com> writes:
> 
> Eric> This patch adds a 4th piece of information, the name of the
> Eric> object being created.  An obvious situation where this will be
> Eric> useful is devtmpfs (although you'll find other examples in the
> Eric> above thread).  devtmpfs when it creates char/block devices is
> Eric> unable to distinguish between kmem and console and so they are
> Eric> created with a generic label.  hotplug/udev is then called which
> Eric> does some pathname like matching and relabels them to something
> Eric> more specific.  We've found that many people are able to race
> Eric> against this particular updating and get spurious denials in
> Eric> /dev.  With this patch devtmpfs will be able to get the labels
> Eric> correct to begin with.
> 
> So your Label based access controls are *also* based on pathnames?
> Right?

Access decisions are still based solely on the label.  This patch can
influence how new objects get their label, which makes the access
decisions indirectly path based.  You'll find a reasonable summary and
commentary on lwn in this weeks security section.