From: Ralph Campbell <rcampbell@nvidia.com>
To: Tycho Andersen <tycho@docker.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Marco Benatto <marco.antonio.780@gmail.com>,
Juerg Haefliger <juerg.haefliger@canonical.com>,
"x86@kernel.org" <x86@kernel.org>
Subject: RE: [PATCH v6 03/11] mm, x86: Add support for eXclusive Page Frame Ownership (XPFO)
Date: Thu, 7 Sep 2017 18:33:09 +0000 [thread overview]
Message-ID: <c08ca2d4ac7f4b9a8987f282e697d30c@HQMAIL105.nvidia.com> (raw)
In-Reply-To: <20170907173609.22696-4-tycho@docker.com>
> -----Original Message-----
> From: owner-linux-mm@kvack.org [mailto:owner-linux-mm@kvack.org] On
> Behalf Of Tycho Andersen
> Sent: Thursday, September 7, 2017 10:36 AM
> To: linux-kernel@vger.kernel.org
> Cc: linux-mm@kvack.org; kernel-hardening@lists.openwall.com; Marco Benatto
> <marco.antonio.780@gmail.com>; Juerg Haefliger
> <juerg.haefliger@canonical.com>; x86@kernel.org; Tycho Andersen
> <tycho@docker.com>
> Subject: [PATCH v6 03/11] mm, x86: Add support for eXclusive Page Frame
> Ownership (XPFO)
>
> From: Juerg Haefliger <juerg.haefliger@canonical.com>
>
> This patch adds support for XPFO which protects against 'ret2dir' kernel attacks.
> The basic idea is to enforce exclusive ownership of page frames by either the
> kernel or userspace, unless explicitly requested by the kernel. Whenever a page
> destined for userspace is allocated, it is unmapped from physmap (the kernel's
> page table). When such a page is reclaimed from userspace, it is mapped back to
> physmap.
>
> Additional fields in the page_ext struct are used for XPFO housekeeping,
> specifically:
> - two flags to distinguish user vs. kernel pages and to tag unmapped
> pages.
> - a reference counter to balance kmap/kunmap operations.
> - a lock to serialize access to the XPFO fields.
>
> This patch is based on the work of Vasileios P. Kemerlis et al. who published their
> work in this paper:
> http://www.cs.columbia.edu/~vpk/papers/ret2dir.sec14.pdf
>
> v6: * use flush_tlb_kernel_range() instead of __flush_tlb_one, so we flush
> the tlb entry on all CPUs when unmapping it in kunmap
> * handle lookup_page_ext()/lookup_xpfo() returning NULL
> * drop lots of BUG()s in favor of WARN()
> * don't disable irqs in xpfo_kmap/xpfo_kunmap, export
> __split_large_page so we can do our own alloc_pages(GFP_ATOMIC) to
> pass it
>
> CC: x86@kernel.org
> Suggested-by: Vasileios P. Kemerlis <vpk@cs.columbia.edu>
> Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>
> Signed-off-by: Tycho Andersen <tycho@docker.com>
> Signed-off-by: Marco Benatto <marco.antonio.780@gmail.com>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 2 +
> arch/x86/Kconfig | 1 +
> arch/x86/include/asm/pgtable.h | 25 +++
> arch/x86/mm/Makefile | 1 +
> arch/x86/mm/pageattr.c | 22 +--
> arch/x86/mm/xpfo.c | 114 ++++++++++++
> include/linux/highmem.h | 15 +-
> include/linux/xpfo.h | 42 +++++
> mm/Makefile | 1 +
> mm/page_alloc.c | 2 +
> mm/page_ext.c | 4 +
> mm/xpfo.c | 222 ++++++++++++++++++++++++
> security/Kconfig | 19 ++
> 13 files changed, 449 insertions(+), 21 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt
> b/Documentation/admin-guide/kernel-parameters.txt
> index d9c171ce4190..444d83183f75 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2736,6 +2736,8 @@
>
> nox2apic [X86-64,APIC] Do not enable x2APIC mode.
>
> + noxpfo [X86-64] Disable XPFO when CONFIG_XPFO is on.
> +
> cpu0_hotplug [X86] Turn on CPU0 hotplug feature when
> CONFIG_BOOTPARAM_HOTPLUG_CPU0 is off.
> Some features depend on CPU0. Known dependencies
<... snip>
A bit more description for system administrators would be very useful.
Perhaps something like:
noxpfo [XPFO,X86-64] Disable eXclusive Page Frame Ownership (XPFO)
Physical pages mapped into user applications will also be mapped
in the kernel's address space as if CONFIG_XPFO was not enabled.
Patch 05 should also update kernel-parameters.txt and add "ARM64" to the config option list for noxpfo.
next prev parent reply other threads:[~2017-09-07 18:35 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-07 17:35 [PATCH v6 00/11] Add support for eXclusive Page Frame Ownership Tycho Andersen
2017-09-07 17:35 ` [PATCH v6 01/11] mm: add MAP_HUGETLB support to vm_mmap Tycho Andersen
2017-09-08 7:42 ` Christoph Hellwig
2017-09-07 17:36 ` [PATCH v6 02/11] x86: always set IF before oopsing from page fault Tycho Andersen
2017-09-07 17:36 ` [PATCH v6 03/11] mm, x86: Add support for eXclusive Page Frame Ownership (XPFO) Tycho Andersen
2017-09-07 18:33 ` Ralph Campbell [this message]
2017-09-07 18:50 ` Tycho Andersen
2017-09-08 7:51 ` Christoph Hellwig
2017-09-08 14:58 ` Tycho Andersen
2017-09-09 15:35 ` Laura Abbott
2017-09-11 15:03 ` Tycho Andersen
2017-09-11 7:24 ` Yisheng Xie
2017-09-11 14:50 ` Tycho Andersen
2017-09-11 16:03 ` Juerg Haefliger
2017-09-11 16:59 ` Tycho Andersen
2017-09-12 8:05 ` Yisheng Xie
2017-09-12 14:36 ` Tycho Andersen
2017-09-12 18:13 ` Tycho Andersen
2017-09-14 6:15 ` Yisheng Xie
2017-09-20 23:46 ` Dave Hansen
2017-09-21 0:02 ` Tycho Andersen
2017-09-21 0:04 ` Dave Hansen
2017-09-11 18:32 ` Tycho Andersen
2017-09-11 21:54 ` Marco Benatto
2017-09-20 15:48 ` Dave Hansen
2017-09-20 22:34 ` Tycho Andersen
2017-09-20 23:21 ` Dave Hansen
2017-09-21 0:09 ` Tycho Andersen
2017-09-21 0:27 ` Dave Hansen
2017-09-21 1:37 ` Tycho Andersen
2017-11-10 1:09 ` Tycho Andersen
2017-11-13 22:20 ` Dave Hansen
2017-11-13 22:46 ` Dave Hansen
2017-11-15 0:33 ` [kernel-hardening] " Tycho Andersen
2017-11-15 0:37 ` Dave Hansen
2017-11-15 0:42 ` Tycho Andersen
2017-11-15 3:44 ` Matthew Wilcox
2017-11-15 7:00 ` Dave Hansen
2017-11-15 14:58 ` Matthew Wilcox
2017-11-15 16:20 ` [kernel-hardening] " Tycho Andersen
2017-11-15 21:34 ` Matthew Wilcox
2017-09-21 0:03 ` Dave Hansen
2017-09-21 0:28 ` Dave Hansen
2017-09-21 1:04 ` Tycho Andersen
2017-09-07 17:36 ` [PATCH v6 04/11] swiotlb: Map the buffer if it was unmapped by XPFO Tycho Andersen
2017-09-07 18:10 ` Christoph Hellwig
2017-09-07 18:44 ` Tycho Andersen
2017-09-08 7:13 ` Christoph Hellwig
2017-09-07 17:36 ` [PATCH v6 05/11] arm64/mm: Add support for XPFO Tycho Andersen
2017-09-08 7:53 ` Christoph Hellwig
2017-09-08 17:24 ` Tycho Andersen
2017-09-14 10:41 ` Julien Grall
2017-09-14 11:29 ` Juergen Gross
2017-09-14 18:22 ` [kernel-hardening] " Mark Rutland
2017-09-18 21:27 ` Tycho Andersen
2017-09-07 17:36 ` [PATCH v6 06/11] xpfo: add primitives for mapping underlying memory Tycho Andersen
2017-09-07 17:36 ` [PATCH v6 07/11] arm64/mm, xpfo: temporarily map dcache regions Tycho Andersen
2017-09-14 18:25 ` Mark Rutland
2017-09-18 21:29 ` Tycho Andersen
2017-09-07 17:36 ` [PATCH v6 08/11] arm64/mm: Add support for XPFO to swiotlb Tycho Andersen
2017-09-07 17:36 ` [PATCH v6 09/11] arm64/mm: disable section/contiguous mappings if XPFO is enabled Tycho Andersen
2017-09-09 15:38 ` Laura Abbott
2017-09-07 17:36 ` [PATCH v6 10/11] mm: add a user_virt_to_phys symbol Tycho Andersen
2017-09-08 7:55 ` Christoph Hellwig
2017-09-08 15:44 ` Kees Cook
2017-09-11 7:36 ` Christoph Hellwig
2017-09-14 18:34 ` [kernel-hardening] " Mark Rutland
2017-09-18 20:56 ` Tycho Andersen
2017-09-07 17:36 ` [PATCH v6 11/11] lkdtm: Add test for XPFO Tycho Andersen
2017-09-07 19:08 ` Kees Cook
2017-09-10 0:57 ` kbuild test robot
2017-09-11 10:34 ` [PATCH v6 00/11] Add support for eXclusive Page Frame Ownership Yisheng Xie
2017-09-11 15:02 ` Tycho Andersen
2017-09-12 7:07 ` Yisheng Xie
2017-09-12 7:40 ` Juerg Haefliger
2017-09-12 8:11 ` Yisheng Xie
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