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[209.132.180.67]) by mx.google.com with ESMTP id z8si629991pgk.183.2019.01.16.21.13.44; Wed, 16 Jan 2019 21:14:00 -0800 (PST) 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; Authentication-Results: mx.google.com; dkim=pass header.i=@amazon.de header.s=amazon201209 header.b=B0mp1JeW; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=amazon.de Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393767AbfAPPAA (ORCPT + 99 others); Wed, 16 Jan 2019 10:00:00 -0500 Received: from smtp-fw-9102.amazon.com ([207.171.184.29]:26902 "EHLO smtp-fw-9102.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728675AbfAPPAA (ORCPT ); Wed, 16 Jan 2019 10:00:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazon201209; t=1547650799; x=1579186799; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=RaiNxQUKMt3ENI0wPF/bEAsbn6PzyzrB2L8Q11F+LsQ=; b=B0mp1JeW0Irq10CKbd5zRgNoRO8cJxLlVppKUJP9MQFagYlZVphTifeE XUFxUsDRm0MZoharn4IgmB3Bec/zgEYlKOK2D4B1dYxZE2CYiD+SygAD4 c6TqapEHoIRFUyOlu20OmxSIW2aScCKHnE8d1sK/L2ZLXdH4JoIH/4lEG I=; X-IronPort-AV: E=Sophos;i="5.56,253,1539648000"; d="scan'208";a="653786779" Received: from sea3-co-svc-lb6-vlan3.sea.amazon.com (HELO email-inbound-relay-1d-74cf8b49.us-east-1.amazon.com) ([10.47.22.38]) by smtp-border-fw-out-9102.sea19.amazon.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 16 Jan 2019 14:57:10 +0000 Received: from u54ee758033e858cfa736.ant.amazon.com (iad7-ws-svc-lb50-vlan2.amazon.com [10.0.93.210]) by email-inbound-relay-1d-74cf8b49.us-east-1.amazon.com (8.14.7/8.14.7) with ESMTP id x0GEujFk043915 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Wed, 16 Jan 2019 14:56:47 GMT From: Julian Stecklina To: Khalid Aziz Cc: juergh@gmail.com, tycho@tycho.ws, ak@linux.intel.com, torvalds@linux-foundation.org, liran.alon@oracle.com, keescook@google.com, konrad.wilk@oracle.com, deepa.srinivasan@oracle.com, chris.hyser@oracle.com, tyhicks@canonical.com, dwmw@amazon.co.uk, andrew.cooper3@citrix.com, jcm@redhat.com, boris.ostrovsky@oracle.com, kanth.ghatraju@oracle.com, joao.m.martins@oracle.com, jmattson@google.com, pradeep.vincent@oracle.com, john.haxby@oracle.com, tglx@linutronix.de, kirill.shutemov@linux.intel.com, hch@lst.de, steven.sistare@oracle.com, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v7 00/16] Add support for eXclusive Page Frame Ownership References: Date: Wed, 16 Jan 2019 15:56:44 +0100 In-Reply-To: (Khalid Aziz's message of "Thu, 10 Jan 2019 14:09:32 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Khalid Aziz 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