Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Tue, 13 Feb 2018 13:43:49 -0800
From: Kees Cook <keescook@...omium.org>
To: Laura Abbott <labbott@...hat.com>
Cc: Jann Horn <jannh@...gle.com>, Igor Stoppa <igor.stoppa@...wei.com>, 
	Boris Lukashev <blukashev@...pervictus.com>, Christopher Lameter <cl@...ux.com>, 
	Matthew Wilcox <willy@...radead.org>, Jerome Glisse <jglisse@...hat.com>, 
	Michal Hocko <mhocko@...nel.org>, Christoph Hellwig <hch@...radead.org>, 
	linux-security-module <linux-security-module@...r.kernel.org>, Linux-MM <linux-mm@...ck.org>, 
	kernel list <linux-kernel@...r.kernel.org>, 
	Kernel Hardening <kernel-hardening@...ts.openwall.com>
Subject: Re: [PATCH 4/6] Protectable Memory

On Tue, Feb 13, 2018 at 8:09 AM, Laura Abbott <labbott@...hat.com> wrote:
> No, arm64 doesn't fixup the aliases, mostly because arm64 uses larger
> page sizes which can't be broken down at runtime. CONFIG_PAGE_POISONING
> does use 4K pages which could be adjusted at runtime. So yes, you are
> right we would have physmap exposure on arm64 as well.

Errr, so that means even modules and kernel code are writable via the
arm64 physmap? That seems extraordinarily bad. :(

-Kees

-- 
Kees Cook
Pixel Security

Powered by blists - more mailing lists

Your e-mail address:

Powered by Openwall GNU/*/Linux - Powered by OpenVZ