From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 860C26B0005 for ; Wed, 20 Jul 2016 06:24:13 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id y134so91237779pfg.1 for ; Wed, 20 Jul 2016 03:24:13 -0700 (PDT) Received: from mail-pa0-x244.google.com (mail-pa0-x244.google.com. [2607:f8b0:400e:c03::244]) by mx.google.com with ESMTPS id b6si2714268pag.62.2016.07.20.03.24.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Jul 2016 03:24:12 -0700 (PDT) Received: by mail-pa0-x244.google.com with SMTP id q2so3084928pap.0 for ; Wed, 20 Jul 2016 03:24:12 -0700 (PDT) Message-ID: <1469010283.2800.5.camel@gmail.com> Subject: Re: [PATCH v3 02/11] mm: Hardened usercopy From: Balbir Singh Date: Wed, 20 Jul 2016 20:24:43 +1000 In-Reply-To: References: <1468619065-3222-1-git-send-email-keescook@chromium.org> <1468619065-3222-3-git-send-email-keescook@chromium.org> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Kees Cook , Laura Abbott Cc: LKML , Daniel Micay , Josh Poimboeuf , Rik van Riel , Casey Schaufler , PaX Team , Brad Spengler , Russell King , Catalin Marinas , Will Deacon , Ard Biesheuvel , Benjamin Herrenschmidt , Michael Ellerman , Tony Luck , Fenghua Yu , "David S. Miller" , "x86@kernel.org" , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Andy Lutomirski , Borislav Petkov , Mathias Krause , Jan Kara , Vitaly Wool , Andrea Arcangeli , Dmitry Vyukov , "linux-arm-kernel@lists.infradead.org" , linux-ia64@vger.kernel.org, "linuxppc-dev@lists.ozlabs.org" , sparclinux , linux-arch , Linux-MM , "kernel-hardening@lists.openwall.com" On Tue, 2016-07-19 at 11:48 -0700, Kees Cook wrote: > On Mon, Jul 18, 2016 at 6:06 PM, Laura Abbott wrote: > >A > > On 07/15/2016 02:44 PM, Kees Cook wrote: > >A > > This doesn't work when copying CMA allocated memory since CMA purposely > > allocates larger than a page block size without setting head pages. > > Given CMA may be used with drivers doing zero copy buffers, I think it > > should be permitted. > >A > > Something like the following lets it pass (I can clean up and submit > > the is_migrate_cma_page APIs as a separate patch for review) > Yeah, this would be great. I'd rather use an accessor to check this > than a direct check for MIGRATE_CMA. > > > A A A A A A A A A */ > > A A A A A A A A for (; ptr <= end ; ptr += PAGE_SIZE, page = virt_to_head_page(ptr)) > > { > > -A A A A A A A A A A A A A A A if (!PageReserved(page)) > > +A A A A A A A A A A A A A A A if (!PageReserved(page) && !is_migrate_cma_page(page)) > > A A A A A A A A A A A A A A A A A A A A A A A A return ""; > > A A A A A A A A } > Yeah, I'll modify this a bit so that which type it starts as is > maintained for all pages (rather than allowing to flip back and forth > -- even though that is likely impossible). >A Sorry, I completely missed the MIGRATE_CMA bits. Could you clarify if you caught this in testing/review? Balbir Singh. -- 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