linux-kernel - Re: [kernel-hardening] [PATCH 4/6] Protectable Memory

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Message-ID: <13a50f85-bbd8-5d78-915a-a29c4a9f0c32@redhat.com>
Date:   Tue, 13 Feb 2018 10:10:13 -0800
From:   Laura Abbott <labbott@...hat.com>
To:     Igor Stoppa <igor.stoppa@...wei.com>,
        Kees Cook <keescook@...omium.org>
Cc:     Boris Lukashev <blukashev@...pervictus.com>,
        Christopher Lameter <cl@...ux.com>,
        Matthew Wilcox <willy@...radead.org>,
        Jann Horn <jannh@...gle.com>,
        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: [kernel-hardening] [PATCH 4/6] Protectable Memory

On 02/13/2018 07:20 AM, Igor Stoppa wrote:
> Why alterations of page properties are not considered a risk and the physmap is?
> And how would it be easier (i suppose) to attack the latter?

Alterations are certainly a risk but with the physmap the
mapping is already there. Find the address and you have
access vs. needing to actually modify the properties
then do the access. I could also be complete off base
on my threat model here so please correct me if I'm
wrong.

I think your other summaries are good points though
and should go in the cover letter.

Thanks,
Laura