From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id D18A86B0055 for ; Thu, 28 May 2009 08:48:03 -0400 (EDT) Date: Thu, 28 May 2009 14:48:40 +0200 From: Pavel Machek Subject: Re: [patch 0/5] Support for sanitization flag in low-level page allocator Message-ID: <20090528124840.GB1421@ucw.cz> References: <20090520183045.GB10547@oblivion.subreption.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090520183045.GB10547@oblivion.subreption.com> Sender: owner-linux-mm@kvack.org To: "Larry H." Cc: linux-kernel@vger.kernel.org, Linus Torvalds , linux-mm@kvack.org, Ingo Molnar List-ID: Hi! > Index: linux-2.6/mm/Kconfig > =================================================================== > --- linux-2.6.orig/mm/Kconfig > +++ linux-2.6/mm/Kconfig > @@ -155,6 +155,26 @@ config PAGEFLAGS_EXTENDED > def_bool y > depends on 64BIT || SPARSEMEM_VMEMMAP || !NUMA || !SPARSEMEM > > +config PAGE_SENSITIVE > + bool "Support for selective page sanitization" > + help > + This option provides support for honoring the sensitive bit > + in the low level page allocator. This bit is used to mark > + pages that will contain sensitive information (such as > + cryptographic secrets and credentials). > + > + Pages marked with the sensitive bit will be sanitized upon > + release, to prevent information leaks and data remanence that > + could allow Iceman/coldboot attacks to reveal such data. > + > + If you are unsure, select N. This option might introduce a > + minimal performance impact on those subsystems that make > + use of the flag associated with the sensitive bit. > + > + If you use the cryptographic API or want to prevent tty > + information leaks locally, you most likely want to enable > + this. This should not be configurable. Runtime config, defaulting to 'sanitize' may make some sense, but... better just be secure. -- (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