From: Laura Abbott <labbott@redhat.com>
To: Kees Cook <keescook@chromium.org>
Cc: Jann Horn <jannh@google.com>,
Igor Stoppa <igor.stoppa@huawei.com>,
Boris Lukashev <blukashev@sempervictus.com>,
Christopher Lameter <cl@linux.com>,
Matthew Wilcox <willy@infradead.org>,
Jerome Glisse <jglisse@redhat.com>,
Michal Hocko <mhocko@kernel.org>,
Christoph Hellwig <hch@infradead.org>,
linux-security-module <linux-security-module@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
kernel list <linux-kernel@vger.kernel.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: arm64 physmap (was Re: [kernel-hardening] [PATCH 4/6] Protectable Memory)
Date: Wed, 14 Feb 2018 11:06:06 -0800 [thread overview]
Message-ID: <2f23544a-bd24-1e71-967b-e8d1cf5a20a3@redhat.com> (raw)
In-Reply-To: <CAGXu5j+zOCLerneUt2b-tvyLLg7fEbr9B0YYow-4DH6oV-nnCw@mail.gmail.com>
On 02/13/2018 01:43 PM, Kees Cook wrote:
> On Tue, Feb 13, 2018 at 8:09 AM, Laura Abbott <labbott@redhat.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
>
(adding linux-arm-kernel and changing the subject)
Kernel code should be fine, if it isn't that is a bug that should be
fixed. Modules yes are not fully protected. The conclusion from past
experience has been that we cannot safely break down larger page sizes
at runtime like x86 does. We could theoretically
add support for fixing up the alias if PAGE_POISONING is enabled but
I don't know who would actually use that in production. Performance
is very poor at that point.
Thanks,
Laura
WARNING: multiple messages have this Message-ID (diff)
From: labbott@redhat.com (Laura Abbott)
To: linux-security-module@vger.kernel.org
Subject: arm64 physmap (was Re: [kernel-hardening] [PATCH 4/6] Protectable Memory)
Date: Wed, 14 Feb 2018 11:06:06 -0800 [thread overview]
Message-ID: <2f23544a-bd24-1e71-967b-e8d1cf5a20a3@redhat.com> (raw)
In-Reply-To: <CAGXu5j+zOCLerneUt2b-tvyLLg7fEbr9B0YYow-4DH6oV-nnCw@mail.gmail.com>
On 02/13/2018 01:43 PM, Kees Cook wrote:
> On Tue, Feb 13, 2018 at 8:09 AM, Laura Abbott <labbott@redhat.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
>
(adding linux-arm-kernel and changing the subject)
Kernel code should be fine, if it isn't that is a bug that should be
fixed. Modules yes are not fully protected. The conclusion from past
experience has been that we cannot safely break down larger page sizes
at runtime like x86 does. We could theoretically
add support for fixing up the alias if PAGE_POISONING is enabled but
I don't know who would actually use that in production. Performance
is very poor at that point.
Thanks,
Laura
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WARNING: multiple messages have this Message-ID (diff)
From: Laura Abbott <labbott@redhat.com>
To: Kees Cook <keescook@chromium.org>
Cc: Jann Horn <jannh@google.com>,
Igor Stoppa <igor.stoppa@huawei.com>,
Boris Lukashev <blukashev@sempervictus.com>,
Christopher Lameter <cl@linux.com>,
Matthew Wilcox <willy@infradead.org>,
Jerome Glisse <jglisse@redhat.com>,
Michal Hocko <mhocko@kernel.org>,
Christoph Hellwig <hch@infradead.org>,
linux-security-module <linux-security-module@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
kernel list <linux-kernel@vger.kernel.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: arm64 physmap (was Re: [kernel-hardening] [PATCH 4/6] Protectable Memory)
Date: Wed, 14 Feb 2018 11:06:06 -0800 [thread overview]
Message-ID: <2f23544a-bd24-1e71-967b-e8d1cf5a20a3@redhat.com> (raw)
In-Reply-To: <CAGXu5j+zOCLerneUt2b-tvyLLg7fEbr9B0YYow-4DH6oV-nnCw@mail.gmail.com>
On 02/13/2018 01:43 PM, Kees Cook wrote:
> On Tue, Feb 13, 2018 at 8:09 AM, Laura Abbott <labbott@redhat.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
>
(adding linux-arm-kernel and changing the subject)
Kernel code should be fine, if it isn't that is a bug that should be
fixed. Modules yes are not fully protected. The conclusion from past
experience has been that we cannot safely break down larger page sizes
at runtime like x86 does. We could theoretically
add support for fixing up the alias if PAGE_POISONING is enabled but
I don't know who would actually use that in production. Performance
is very poor at that point.
Thanks,
Laura
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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see: http://www.linux-mm.org/ .
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WARNING: multiple messages have this Message-ID (diff)
From: labbott@redhat.com (Laura Abbott)
To: linux-arm-kernel@lists.infradead.org
Subject: arm64 physmap (was Re: [kernel-hardening] [PATCH 4/6] Protectable Memory)
Date: Wed, 14 Feb 2018 11:06:06 -0800 [thread overview]
Message-ID: <2f23544a-bd24-1e71-967b-e8d1cf5a20a3@redhat.com> (raw)
In-Reply-To: <CAGXu5j+zOCLerneUt2b-tvyLLg7fEbr9B0YYow-4DH6oV-nnCw@mail.gmail.com>
On 02/13/2018 01:43 PM, Kees Cook wrote:
> On Tue, Feb 13, 2018 at 8:09 AM, Laura Abbott <labbott@redhat.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
>
(adding linux-arm-kernel and changing the subject)
Kernel code should be fine, if it isn't that is a bug that should be
fixed. Modules yes are not fully protected. The conclusion from past
experience has been that we cannot safely break down larger page sizes
at runtime like x86 does. We could theoretically
add support for fixing up the alias if PAGE_POISONING is enabled but
I don't know who would actually use that in production. Performance
is very poor at that point.
Thanks,
Laura
next prev parent reply other threads:[~2018-02-14 19:06 UTC|newest]
Thread overview: 171+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-24 17:56 [kernel-hardening] [RFC PATCH v11 0/6] mm: security: ro protection for dynamic data Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` [kernel-hardening] [PATCH 1/6] genalloc: track beginning of allocations Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` [kernel-hardening] [PATCH 2/6] genalloc: selftest Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` [kernel-hardening] [PATCH 3/6] struct page: add field for vm_struct Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` [kernel-hardening] [PATCH 4/6] Protectable Memory Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 19:10 ` [kernel-hardening] " Jann Horn
2018-01-24 19:10 ` Jann Horn
2018-01-24 19:10 ` Jann Horn
2018-01-25 11:59 ` Igor Stoppa
2018-01-25 11:59 ` Igor Stoppa
2018-01-25 11:59 ` Igor Stoppa
2018-01-25 11:59 ` Igor Stoppa
2018-01-25 15:14 ` Boris Lukashev
2018-01-25 15:14 ` Boris Lukashev
2018-01-25 15:14 ` Boris Lukashev
2018-01-25 15:38 ` Jerome Glisse
2018-01-25 15:38 ` Jerome Glisse
2018-01-25 15:38 ` Jerome Glisse
2018-01-26 12:28 ` Igor Stoppa
2018-01-26 12:28 ` Igor Stoppa
2018-01-26 12:28 ` Igor Stoppa
2018-01-26 16:36 ` Boris Lukashev
2018-01-26 16:36 ` Boris Lukashev
2018-01-26 16:36 ` Boris Lukashev
2018-01-30 13:46 ` Igor Stoppa
2018-01-30 13:46 ` Igor Stoppa
2018-01-30 13:46 ` Igor Stoppa
2018-01-26 5:35 ` Matthew Wilcox
2018-01-26 5:35 ` Matthew Wilcox
2018-01-26 5:35 ` Matthew Wilcox
2018-01-26 11:46 ` Igor Stoppa
2018-01-26 11:46 ` Igor Stoppa
2018-01-26 11:46 ` Igor Stoppa
2018-01-26 11:46 ` Igor Stoppa
2018-02-02 18:39 ` Christopher Lameter
2018-02-02 18:39 ` Christopher Lameter
2018-02-02 18:39 ` Christopher Lameter
2018-02-03 15:38 ` Igor Stoppa
2018-02-03 15:38 ` Igor Stoppa
2018-02-03 15:38 ` Igor Stoppa
2018-02-03 15:38 ` Igor Stoppa
2018-02-03 19:57 ` Igor Stoppa
2018-02-03 19:57 ` Igor Stoppa
2018-02-03 19:57 ` Igor Stoppa
2018-02-03 19:57 ` Igor Stoppa
2018-02-03 20:12 ` Boris Lukashev
2018-02-03 20:12 ` Boris Lukashev
2018-02-03 20:12 ` Boris Lukashev
2018-02-03 20:32 ` Igor Stoppa
2018-02-03 20:32 ` Igor Stoppa
2018-02-03 20:32 ` Igor Stoppa
2018-02-03 22:29 ` Boris Lukashev
2018-02-03 22:29 ` Boris Lukashev
2018-02-03 22:29 ` Boris Lukashev
2018-02-04 15:05 ` Igor Stoppa
2018-02-04 15:05 ` Igor Stoppa
2018-02-04 15:05 ` Igor Stoppa
2018-02-12 23:27 ` Kees Cook
2018-02-12 23:27 ` Kees Cook
2018-02-12 23:27 ` Kees Cook
2018-02-13 0:40 ` Laura Abbott
2018-02-13 0:40 ` Laura Abbott
2018-02-13 0:40 ` Laura Abbott
2018-02-13 1:25 ` Kees Cook
2018-02-13 1:25 ` Kees Cook
2018-02-13 1:25 ` Kees Cook
2018-02-13 3:39 ` Jann Horn
2018-02-13 3:39 ` Jann Horn
2018-02-13 3:39 ` Jann Horn
2018-02-13 16:09 ` Laura Abbott
2018-02-13 16:09 ` Laura Abbott
2018-02-13 16:09 ` Laura Abbott
2018-02-13 21:43 ` Kees Cook
2018-02-13 21:43 ` Kees Cook
2018-02-13 21:43 ` Kees Cook
2018-02-14 19:06 ` Laura Abbott [this message]
2018-02-14 19:06 ` arm64 physmap (was Re: [kernel-hardening] [PATCH 4/6] Protectable Memory) Laura Abbott
2018-02-14 19:06 ` Laura Abbott
2018-02-14 19:06 ` Laura Abbott
2018-02-14 19:28 ` Ard Biesheuvel
2018-02-14 19:28 ` Ard Biesheuvel
2018-02-14 19:28 ` Ard Biesheuvel
2018-02-14 19:28 ` Ard Biesheuvel
2018-02-14 20:13 ` Laura Abbott
2018-02-14 20:13 ` Laura Abbott
2018-02-14 20:13 ` Laura Abbott
2018-02-14 20:13 ` Laura Abbott
2018-02-14 19:29 ` Kees Cook
2018-02-14 19:29 ` Kees Cook
2018-02-14 19:29 ` Kees Cook
2018-02-14 19:29 ` Kees Cook
2018-02-14 19:35 ` Kees Cook
2018-02-14 19:35 ` Kees Cook
2018-02-14 19:35 ` Kees Cook
2018-02-14 19:35 ` Kees Cook
2018-02-20 16:28 ` Igor Stoppa
2018-02-20 16:28 ` Igor Stoppa
2018-02-20 16:28 ` Igor Stoppa
2018-02-20 16:28 ` Igor Stoppa
2018-02-21 22:22 ` Kees Cook
2018-02-21 22:22 ` Kees Cook
2018-02-21 22:22 ` Kees Cook
2018-02-21 22:22 ` Kees Cook
2018-02-14 19:48 ` Kees Cook
2018-02-14 19:48 ` Kees Cook
2018-02-14 19:48 ` Kees Cook
2018-02-14 19:48 ` Kees Cook
2018-02-14 22:13 ` Tycho Andersen
2018-02-14 22:13 ` Tycho Andersen
2018-02-14 22:13 ` Tycho Andersen
2018-02-14 22:13 ` Tycho Andersen
2018-02-14 22:27 ` Kees Cook
2018-02-14 22:27 ` Kees Cook
2018-02-14 22:27 ` Kees Cook
2018-02-14 22:27 ` Kees Cook
2018-02-13 15:20 ` [kernel-hardening] [PATCH 4/6] Protectable Memory Igor Stoppa
2018-02-13 15:20 ` Igor Stoppa
2018-02-13 15:20 ` Igor Stoppa
2018-02-13 15:20 ` Igor Stoppa
2018-02-13 15:20 ` [kernel-hardening] " Igor Stoppa
[not found] ` <5a83024c.64369d0a.a1e94.cdd6SMTPIN_ADDED_BROKEN@mx.google.com>
2018-02-13 18:10 ` Laura Abbott
2018-02-13 18:10 ` Laura Abbott
2018-02-13 18:10 ` Laura Abbott
2018-02-20 17:16 ` Igor Stoppa
2018-02-20 17:16 ` Igor Stoppa
2018-02-20 17:16 ` Igor Stoppa
2018-02-21 22:37 ` Kees Cook
2018-02-21 22:37 ` Kees Cook
2018-02-21 22:37 ` Kees Cook
2018-02-05 15:40 ` Christopher Lameter
2018-02-05 15:40 ` Christopher Lameter
2018-02-05 15:40 ` Christopher Lameter
2018-02-09 11:17 ` Igor Stoppa
2018-02-09 11:17 ` Igor Stoppa
2018-02-09 11:17 ` Igor Stoppa
2018-02-09 11:17 ` Igor Stoppa
2018-01-26 19:41 ` [kernel-hardening] " Igor Stoppa
2018-01-26 19:41 ` Igor Stoppa
2018-01-26 19:41 ` Igor Stoppa
2018-01-26 19:41 ` Igor Stoppa
2018-01-24 17:56 ` [kernel-hardening] [PATCH 5/6] Documentation for Pmalloc Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 19:14 ` [kernel-hardening] " Ralph Campbell
2018-01-24 19:14 ` Ralph Campbell
2018-01-24 19:14 ` Ralph Campbell
2018-01-24 19:14 ` Ralph Campbell
2018-01-25 7:53 ` [kernel-hardening] " Igor Stoppa
2018-01-25 7:53 ` Igor Stoppa
2018-01-25 7:53 ` Igor Stoppa
2018-01-25 7:53 ` Igor Stoppa
2018-01-24 17:56 ` [kernel-hardening] [PATCH 6/6] Pmalloc: self-test Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
2018-01-24 17:56 ` Igor Stoppa
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