From: Kees Cook <keescook@chromium.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Rik van Riel <riel@surriel.com>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [PATCH] mm: Prevent mapping slab pages to userspace
Date: Tue, 29 Jan 2019 08:00:14 +1300 [thread overview]
Message-ID: <CAGXu5jJkf4pKr0WVUcFitZnnUbq3annautZxzYPC0TQaB5HaGA@mail.gmail.com> (raw)
In-Reply-To: <20190128102055.5b0790549542891c4dca47a3@linux-foundation.org>
On Tue, Jan 29, 2019 at 7:21 AM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Fri, 25 Jan 2019 09:38:27 -0800 Matthew Wilcox <willy@infradead.org> wrote:
>
> > It's never appropriate to map a page allocated by SLAB into userspace.
> > A buggy device driver might try this, or an attacker might be able to
> > find a way to make it happen.
>
> It wouldn't surprise me if someone somewhere is doing this. Rather
> than mysteriously breaking their code, how about we emit a warning and
> still permit it to proceed, for a while?
It seems like a fatal condition to me? There's nothing to check that
such a page wouldn't get freed by the slab while still mapped to
userspace, right?
But I'll take warning over not checking. :)
--
Kees Cook
next prev parent reply other threads:[~2019-01-28 19:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-25 17:38 Matthew Wilcox
2019-01-25 18:44 ` Kees Cook
2019-01-25 18:44 ` Kees Cook
2019-01-25 19:30 ` Matthew Wilcox
2019-01-28 18:20 ` Andrew Morton
2019-01-28 19:00 ` Kees Cook [this message]
2019-01-28 20:08 ` Christopher Lameter
2019-01-31 0:37 ` Michael Ellerman
2019-01-31 6:03 ` Pekka Enberg
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