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Date: Wed, 28 Mar 2012 16:30:44 -0500
From: Serge Hallyn <serge.hallyn@canonical.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Pavel Emelyanov <xemul@parallels.com>
Subject: Re: [rfc] fcntl: Add F_GETOWNER_UIDS option
Message-ID: <20120328213044.GA26190@peqn>
References: <20120327222923.GA31692@mail.hallyn.com>
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 <20120328064838.GA2286@moon>
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 <20120328081639.GB2286@moon>
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Quoting Oleg Nesterov (oleg@redhat.com):
> On 03/28, Serge E. Hallyn wrote:
> >
> > If you want to
> > just add the struct cred to the f_owner and do proper uid conversion,
> > I'll support that too.  (Just grab a ref to the cred in
> > fs/fcntl.c:f_modown(), and drop the ref in fs/file_table.c:__fput() ).
> 
> In this case f_owner.*uid should go away, I guess.

Yup.

Which I guess is all the more reason *not* to do this unless we end up
not going with Eric's userns mapping patchset (which is unlikely).

> And sigio_perm()
> should be unified with kill_ok_by_cred() somehow (modulo
> security_file_send_sigiotask).
> 
> Right?

Maybe, but other differences include current being the signal sender in
one and recipient in the other, and CAP_KILL being relevent in only
one.

-serge