linux-kernel - Re: [RFC PATCH v7 00/16] Add support for eXclusive Page Frame Ownership

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ciirm8o98gzm4z.fsf@u54ee758033e858cfa736.ant.amazon.com>
Date:   Wed, 16 Jan 2019 15:56:44 +0100
From:   Julian Stecklina <jsteckli@...zon.de>
To:     Khalid Aziz <khalid.aziz@...cle.com>
Cc:     juergh@...il.com, tycho@...ho.ws, ak@...ux.intel.com,
        torvalds@...ux-foundation.org, liran.alon@...cle.com,
        keescook@...gle.com, konrad.wilk@...cle.com,
        deepa.srinivasan@...cle.com, chris.hyser@...cle.com,
        tyhicks@...onical.com, dwmw@...zon.co.uk,
        andrew.cooper3@...rix.com, jcm@...hat.com,
        boris.ostrovsky@...cle.com, kanth.ghatraju@...cle.com,
        joao.m.martins@...cle.com, jmattson@...gle.com,
        pradeep.vincent@...cle.com, john.haxby@...cle.com,
        tglx@...utronix.de, kirill.shutemov@...ux.intel.com, hch@....de,
        steven.sistare@...cle.com, kernel-hardening@...ts.openwall.com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v7 00/16] Add support for eXclusive Page Frame Ownership

Khalid Aziz <khalid.aziz@...cle.com> writes:

> I am continuing to build on the work Juerg, Tycho and Julian have done
> on XPFO.

Awesome!

> A rogue process can launch a ret2dir attack only from a CPU that has
> dual mapping for its pages in physmap in its TLB. We can hence defer
> TLB flush on a CPU until a process that would have caused a TLB flush
> is scheduled on that CPU.

Assuming the attacker already has the ability to execute arbitrary code
in userspace, they can just create a second process and thus avoid the
TLB flush. Am I getting this wrong?

Julian