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Date: Sat, 7 Mar 2015 15:35:54 -0600
From: "Serge E. Hallyn" <serge@hallyn.com>
To: Christoph Lameter <cl@linux.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Serge Hallyn <serge.hallyn@canonical.com>,
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        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        Linux API <linux-api@vger.kernel.org>,
        Michael Kerrisk <mtk.manpages@gmail.com>
Subject: Re: [PATCH] capabilities: Ambient capability set V2
Message-ID: <20150307213554.GB9833@mail.hallyn.com>
References: <alpine.DEB.2.11.1502261612370.8994@gentwo.org>
 <20150301233359.GA22196@mail.hallyn.com>
 <alpine.DEB.2.11.1503050917380.31001@gentwo.org>
 <20150305171326.GA14998@mail.hallyn.com>
 <alpine.DEB.2.11.1503060948460.8207@gentwo.org>
 <20150306163443.GA28386@mail.hallyn.com>
 <alpine.DEB.2.11.1503061244130.9804@gentwo.org>
 <CALCETrVQF22rkZFD8VAW_xrVQOjwpej6W4TJS9gbN9B431TEKg@mail.gmail.com>
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On Sat, Mar 07, 2015 at 09:09:05AM -0600, Christoph Lameter wrote:
> On Fri, 6 Mar 2015, Serge E. Hallyn wrote:
> 
> > > I think that's right.  fI doesn't set pI.
> >
> > Right.  The idea is that for the running binary to get capability x in its
> > pP, its privileged ancestor must have set x in pI, and the binary itself
> > must be trusted with x in fI.
> 
> The ancestor here is ambient_test and when it is run pI will not be set
> despite the cap setting.

ambient_test is supposed to set it.

> Therefore anything is spawns cannot have the inheritance bits set either.
> This plainly does not make any sense whatsoever. If this is so as it seems
> to be then we should be able to remove the inheritance bits because they
> have no effect.
>