Re: hard links create local DoS vulnerability and security problems

Jakob Lell
2003-11-24T18:33:05Z

On Monday 24 November 2003 19:21, Michael Buesch wrote:
> On Monday 24 November 2003 18:57, Jakob Lell wrote:
> > > > To solve the problem, the kernel shouldn't allow users to create hard
> > > > links to
> > > > files belonging to someone else.
> > >
> > > No. Users must be able to create hard links to files that belong
> > > to somebody else if they are readable. It's a requirement.
> >
> > If this is REALLY neccessary, it might be possible to prevent hard links
> > to setuid binaries.
>
> What about _not_ modifying the mainstream-kernel behaviour,
> but adding an option, to make users unable to create such hard-links,
> to selinux and/or grsec?
Hello,
this would be possible. However, most admins don't install this patches and
thus stay vulnerable. Is there any reason why users should be able to create
hard links to setuid programs belonging to anyone else?
Regards
Jakob