From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f50.google.com (mail-wg0-f50.google.com [74.125.82.50]) by kanga.kvack.org (Postfix) with ESMTP id BBE826B0038 for ; Mon, 16 Mar 2015 17:11:25 -0400 (EDT) Received: by wgra20 with SMTP id a20so50235850wgr.3 for ; Mon, 16 Mar 2015 14:11:25 -0700 (PDT) Received: from atrey.karlin.mff.cuni.cz (atrey.karlin.mff.cuni.cz. [195.113.26.193]) by mx.google.com with ESMTP id h5si19970957wie.91.2015.03.16.14.11.24 for ; Mon, 16 Mar 2015 14:11:24 -0700 (PDT) Date: Mon, 16 Mar 2015 22:11:22 +0100 From: Pavel Machek Subject: Re: [RFC, PATCH] pagemap: do not leak physical addresses to non-privileged userspace Message-ID: <20150316211122.GD11441@amd> References: <1425935472-17949-1-git-send-email-kirill@shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1425935472-17949-1-git-send-email-kirill@shutemov.name> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Linus Torvalds , "Kirill A. Shutemov" , Pavel Emelyanov , Konstantin Khlebnikov , Mark Seaborn , Andy Lutomirski On Mon 2015-03-09 23:11:12, Kirill A. Shutemov wrote: > From: "Kirill A. Shutemov" > > As pointed by recent post[1] on exploiting DRAM physical imperfection, > /proc/PID/pagemap exposes sensitive information which can be used to do > attacks. > > This is RFC patch which disallow anybody without CAP_SYS_ADMIN to read > the pagemap. > > Any comments? > > [1] http://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html Note that this kind of attack still works without pagemap, it just takes longer. Actually the first demo program is not using pagemap. Can we do anything about that? Disabling cache flushes from userland should make it no longer exploitable. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org