Date: Fri, 24 Apr 2015 16:15:11 -0500
From: "Serge E. Hallyn" <serge@hallyn.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Christoph Lameter <cl@linux.com>, Serge Hallyn <serge.hallyn@ubuntu.com>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Andrew Lutomirski <luto@kernel.org>, "Ted Ts'o" <tytso@mit.edu>,
        Andrew Morton <akpm@linuxfoundation.org>,
        "Andrew G. Morgan" <morgan@kernel.org>,
        Linux API <linux-api@vger.kernel.org>,
        Mimi Zohar <zohar@linux.vnet.ibm.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Austin S Hemmelgarn <ahferroin7@gmail.com>,
        linux-security-module <linux-security-module@vger.kernel.org>,
        Aaron Jones <aaronmdjones@gmail.com>,
        Serge Hallyn <serge.hallyn@canonical.com>,
        LKML <linux-kernel@vger.kernel.org>, Markku Savela <msa@moth.iki.fi>,
        Kees Cook <keescook@chromium.org>, Jonathan Corbet <corbet@lwn.net>
Subject: Re: [RFC] capabilities: Ambient capabilities
Message-ID: <20150424211511.GB28613@mail.hallyn.com>
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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.

> Also, in my model you can do:
> 
> $ sudo capset cap_whatever=eip something
> $ ./something
> 
> and the program can make its cap be ambient and run a helper.  In the
> CAP_SETPCAP model, that doesn't work.
> 
> --Andy
> 
> -- 
> Andy Lutomirski
> AMA Capital Management, LLC
> --
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