Date: Tue, 24 Jun 2014 21:30:55 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Kees Cook <keescook@chromium.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Alexei Starovoitov <ast@plumgrid.com>,
        "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Daniel Borkmann <dborkman@redhat.com>, Will Drewry <wad@chromium.org>,
        Julien Tinnes <jln@chromium.org>, David Drysdale <drysdale@google.com>,
        Linux API <linux-api@vger.kernel.org>, X86 ML <x86@kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        linux-mips@linux-mips.org, linux-arch <linux-arch@vger.kernel.org>,
        LSM List <linux-security-module@vger.kernel.org>
Subject: Re: [PATCH v7 4/9] seccomp: move no_new_privs into seccomp
Message-ID: <20140624193055.GA4482@redhat.com>
References: <1403560693-21809-1-git-send-email-keescook@chromium.org> <1403560693-21809-5-git-send-email-keescook@chromium.org> <20140624191815.GA3623@redhat.com> <CALCETrVgpP=zOtiQafVgcic2T95TdEM5DTvHYXWTbcZ14xBqHQ@mail.gmail.com>
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On 06/24, Andy Lutomirski wrote:
>
> On Tue, Jun 24, 2014 at 12:18 PM, Oleg Nesterov <oleg@redhat.com> wrote:
> >>
> >> -struct seccomp { };
> >> +struct seccomp {
> >> +     unsigned long flags;
> >> +};
> >
> > A bit messy ;)
> >
> > I am wondering if we can simply do
> >
> >         static inline bool current_no_new_privs(void)
> >         {
> >                 if (current->no_new_privs)
> >                         return true;
> >
> >         #ifdef CONFIG_SECCOMP
> >                 if (test_thread_flag(TIF_SECCOMP))
> >                         return true;
> >         #endif
>
> Nope -- privileged users can enable seccomp w/o nnp.

Indeed, I am stupid.

Still it would be nice to cleanup this somehow. The new member is only
used as a previous ->no_new_privs, just it is long to allow the concurent
set/get. Logically it doesn't even belong to seccomp{}.

Oleg.

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