Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Mon, 29 Jan 2018 14:14:46 +0100
From:   Pavel Machek <pavel@ucw.cz>
To:     Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc:     Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Dominik Brodowski <linux@dominikbrodowski.net>,
        linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
        kvm@vger.kernel.org, Heiko Carstens <heiko.carstens@de.ibm.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Cornelia Huck <cohuck@redhat.com>,
        David Hildenbrand <david@redhat.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jon Masters <jcm@redhat.com>,
        Marcus Meissner <meissner@suse.de>,
        Jiri Kosina <jkosina@suse.cz>, w@1wt.eu, keescook@chromium.org,
        thomas.lendacky@amd.com, dwmw@amazon.co.uk, ak@linux.intel.com
Subject: Re: Avoiding information leaks between users and between processes
 by default? [Was: : [PATCH 1/5] prctl: add PR_ISOLATE_BP process control]
Message-ID: <20180129131446.GB4669@amd>
References: <1516712825-2917-1-git-send-email-schwidefsky@de.ibm.com>
 <1516712825-2917-2-git-send-email-schwidefsky@de.ibm.com>
 <20180123170719.GA4154@isilmar-4.linta.de>
 <20180124072953.50851fec@mschwideX1>
 <20180124083705.GA14868@light.dominikbrodowski.net>
 <20180124111552.GA24675@amd>
 <20180124134803.3e11c6d6@mschwideX1>
 <20180124190105.GA30107@amd>
 <20180124204622.1f7b0de2@alans-desktop>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha1;
        protocol="application/pgp-signature"; boundary="KFztAG8eRSV9hGtP"
Content-Disposition: inline
In-Reply-To: <20180124204622.1f7b0de2@alans-desktop>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


--KFztAG8eRSV9hGtP
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Wed 2018-01-24 20:46:22, Alan Cox wrote:
> > Anyway, no need to add prctl(), if A can ptrace B and B can ptrace A,
> > leaking info between them should not be a big deal. You can probably
> > find existing macros doing neccessary checks.
>=20
> Until one of them is security managed so it shouldn't be able to ptrace
> the other, or (and this is the nasty one) when a process is executing
> code it wants to protect from the rest of the same process (eg an
> untrusted jvm, javascript or probably nastiest of all webassembly)
>=20
> We don't need a prctl for trusted/untrusted IMHO but we do eventually
> need to think about API's for "this lot is me but I don't trust
> it" (flatpack, docker, etc) and for what JIT engines need to do.

Agreed.

And yes, JITs are interesting, and given the latest
rowhammer/sidechannel attacks, something we may want to limit in
future...

It sounds nice on paper but is just risky.
									Pavel
--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

--KFztAG8eRSV9hGtP
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: Digital signature

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1

iEYEARECAAYFAlpvHkYACgkQMOfwapXb+vLk/ACaAsmlr9eMLJNIIMjJLuk8PxK+
1b4An3U1pEZ+etPY3/qYfQid40In7a59
=Cosk
-----END PGP SIGNATURE-----

--KFztAG8eRSV9hGtP--