Date: Sat, 25 Apr 2015 02:45:36 +0000
From: Serge Hallyn <serge.hallyn@ubuntu.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: "Serge E. Hallyn" <serge@hallyn.com>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        "Ted Ts'o" <tytso@mit.edu>, "Andrew G. Morgan" <morgan@kernel.org>,
        Andrew Morton <akpm@linuxfoundation.org>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Mimi Zohar <zohar@linux.vnet.ibm.com>,
        Linux API <linux-api@vger.kernel.org>,
        Austin S Hemmelgarn <ahferroin7@gmail.com>,
        linux-security-module <linux-security-module@vger.kernel.org>,
        Aaron Jones <aaronmdjones@gmail.com>, Christoph Lameter <cl@linux.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Serge Hallyn <serge.hallyn@canonical.com>,
        Markku Savela <msa@moth.iki.fi>, Kees Cook <keescook@chromium.org>,
        Jonathan Corbet <corbet@lwn.net>
Subject: Re: [RFC] capabilities: Ambient capabilities
Message-ID: <20150425024536.GA23915@ubuntumail>
References: <alpine.DEB.2.11.1504091024540.13650@gentwo.org>
 <alpine.DEB.2.11.1504230900260.32203@gentwo.org>
 <20150424175348.GL16377@ubuntumail>
 <CALCETrW5_85mFFTkzCVNA5N1KQeNBrkw2d8FF3H3LYtmz6UAPw@mail.gmail.com>
 <20150424190935.GN16377@ubuntumail>
 <CALCETrV7S0dLkNWMSYsL7MFuLgdpQwUEAjW6zTwRE8uhh_AuBQ@mail.gmail.com>
 <alpine.DEB.2.11.1504241512570.11839@gentwo.org>
 <CALCETrUrFm9n_4xTj4ELkzTSnWHfxQtANqz2wpzU7riTihLDaA@mail.gmail.com>
 <20150424211511.GB28613@mail.hallyn.com>
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Quoting Andy Lutomirski (luto@amacapital.net):
> On Apr 24, 2015 2:15 PM, "Serge E. Hallyn" <serge@hallyn.com> wrote:
> >
> > On Fri, Apr 24, 2015 at 01:18:44PM -0700, Andy Lutomirski wrote:
> > > On Fri, Apr 24, 2015 at 1:13 PM, Christoph Lameter <cl@linux.com> wrote:
> > > > On Fri, 24 Apr 2015, Andy Lutomirski wrote:
> > > >
> > > >> That's sort of what my patch does -- you need CAP_SETPCAP to switch
> > > >> the securebit.
> > > >>
> > > >> But Christoph's patch required it to add caps to the ambient set, right?
> > > >
> > > > Yes but you seem to be just adding one additional step without too much of
> > > > a benefit because you still need CAP_SETPCAP.
> > > >
> > >
> > > No, because I set the default to on :)
> >
> > Right - I definately prefer
> >
> > . default off
> > . CAP_SETPCAP required to turn it on (for self and children)
> > . once on, anyone can copy bits from (whatever we decided) to pA.
> >
> 
> Why default off?  If there's some weird reason that switching it on
> could cause a security problem, then I'd agree, but I haven't spotted
> a reason yet.

Cause it's less scary?

I'll just wait for the new patchset :)
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