[ubuntu-hardened] Removing suid root from binaries where it isn't needed

Kees Cook kees at ubuntu.com
Wed Oct 31 14:29:59 GMT 2007

On Wed, Oct 31, 2007 at 09:52:12AM -0400, Chad Sellers wrote:
> On 10/30/07 11:23 PM, "Kees Cook" <kees at ubuntu.com> wrote:
> > I think the fscap stuff would be a good thing to get into Hardy+1.  We
> > can test it and start the discussion with Debian about it now, though.
> > 
> That sounds like a good plan. Extra thought and testing will be good, as
> this is an area where you have to tread very carefully. You have to account
> for non-xattr filesystems, people who compile their own kernel (possibly
> without fscaps), and many associated corner cases. We actually talked about
> doing something similar with SELinux (authoritative caps [1]), but decided
> against it due to these problems.

Yeah, combined with the prior derooting work, perhaps some of this
results in too many regressions.  From the original list of setuid
tools, perhaps we need to audit for a few things:

- is it already derooted?
  - yes: is the derooting patch upstream?
  - no: can it be derooted?
    - yes: do it; send patch upstream
    - no: can its work be done via capabilities?
      - yes: investigate fscap to replace setuidness
      - no: pull out hair

Martin, is there some list of the packages you worked on for the

Can someone make a matrix of setuid applications that need this
investigation?  Maybe at

With that we can build our checklist and see what needs either derooting
or fscap work.


Kees Cook
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