From: Khalid Aziz <khalid.aziz@oracle.com>
To: Kees Cook <keescook@google.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Nadav Amit <nadav.amit@gmail.com>, Ingo Molnar <mingo@kernel.org>,
Juerg Haefliger <juergh@gmail.com>,
Tycho Andersen <tycho@tycho.ws>,
Julian Stecklina <jsteckli@amazon.de>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Juerg Haefliger <juerg.haefliger@canonical.com>,
deepa.srinivasan@oracle.com, chris hyser <chris.hyser@oracle.com>,
Tyler Hicks <tyhicks@canonical.com>,
David Woodhouse <dwmw@amazon.co.uk>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Jon Masters <jcm@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
iommu <iommu@lists.linux-foundation.org>, X86 ML <x86@kernel.org>,
"linux-alpha@vger.kernel.org"
<linux-arm-kernel@lists.infradead.org>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
LSM List <linux-security-module@vger.kernel.org>,
Khalid Aziz <khalid@gonehiking.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Dave Hansen <dave@sr71.net>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Arjan van de Ven <arjan@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [RFC PATCH v9 03/13] mm: Add support for eXclusive Page Frame Ownership (XPFO)
Date: Mon, 22 Apr 2019 13:30:41 -0600 [thread overview]
Message-ID: <302e3d5b-d2fd-3c25-335b-466ba83035c5@oracle.com> (raw)
In-Reply-To: <8f9d059d-e720-cd24-faa6-45493fc012e0@oracle.com>
On 4/18/19 8:34 AM, Khalid Aziz wrote:
> On 4/17/19 11:41 PM, Kees Cook wrote:
>> On Wed, Apr 17, 2019 at 11:41 PM Andy Lutomirski <luto@kernel.org> wrote:
>>> I don't think this type of NX goof was ever the argument for XPFO.
>>> The main argument I've heard is that a malicious user program writes a
>>> ROP payload into user memory (regular anonymous user memory) and then
>>> gets the kernel to erroneously set RSP (*not* RIP) to point there.
>>
>> Well, more than just ROP. Any of the various attack primitives. The NX
>> stuff is about moving RIP: SMEP-bypassing. But there is still basic
>> SMAP-bypassing for putting a malicious structure in userspace and
>> having the kernel access it via the linear mapping, etc.
>>
>>> I find this argument fairly weak for a couple reasons. First, if
>>> we're worried about this, let's do in-kernel CFI, not XPFO, to
>>
>> CFI is getting much closer. Getting the kernel happy under Clang, LTO,
>> and CFI is under active development. (It's functional for arm64
>> already, and pieces have been getting upstreamed.)
>>
>
> CFI theoretically offers protection with fairly low overhead. I have not
> played much with CFI in clang. I agree with Linus that probability of
> bugs in XPFO implementation itself is a cause of concern. If CFI in
> Clang can provide us the same level of protection as XPFO does, I
> wouldn't want to push for an expensive change like XPFO.
>
> If Clang/CFI can't get us there for extended period of time, does it
> make sense to continue to poke at XPFO?
Any feedback on continued effort on XPFO? If it makes sense to have XPFO
available as a solution for ret2dir issue in case Clang/CFI does not
work out, I will continue to refine it.
--
Khalid
next prev parent reply other threads:[~2019-04-22 19:31 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-03 17:34 [RFC PATCH v9 00/13] Add support for eXclusive Page Frame Ownership Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 01/13] mm: add MAP_HUGETLB support to vm_mmap Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 02/13] x86: always set IF before oopsing from page fault Khalid Aziz
2019-04-04 0:12 ` Andy Lutomirski
2019-04-04 1:42 ` Tycho Andersen
2019-04-04 4:12 ` Andy Lutomirski
2019-04-04 15:47 ` Tycho Andersen
2019-04-04 16:23 ` Sebastian Andrzej Siewior
2019-04-04 16:28 ` Thomas Gleixner
2019-04-04 17:11 ` Andy Lutomirski
2019-04-03 17:34 ` [RFC PATCH v9 03/13] mm: Add support for eXclusive Page Frame Ownership (XPFO) Khalid Aziz
2019-04-04 7:21 ` Peter Zijlstra
2019-04-04 9:25 ` Peter Zijlstra
2019-04-04 14:48 ` Tycho Andersen
2019-04-04 7:43 ` Peter Zijlstra
2019-04-04 15:15 ` Khalid Aziz
2019-04-04 17:01 ` Peter Zijlstra
2019-04-17 16:15 ` Ingo Molnar
2019-04-17 16:49 ` Khalid Aziz
2019-04-17 17:09 ` Ingo Molnar
2019-04-17 17:19 ` Nadav Amit
2019-04-17 17:26 ` Ingo Molnar
2019-04-17 17:44 ` Nadav Amit
2019-04-17 21:19 ` Thomas Gleixner
2019-04-17 23:18 ` Linus Torvalds
2019-04-17 23:42 ` Thomas Gleixner
2019-04-17 23:52 ` Linus Torvalds
2019-04-18 4:41 ` Andy Lutomirski
2019-04-18 5:41 ` Kees Cook
2019-04-18 14:34 ` Khalid Aziz
2019-04-22 19:30 ` Khalid Aziz [this message]
2019-04-22 22:23 ` Kees Cook
2019-04-18 6:14 ` Thomas Gleixner
2019-04-17 17:33 ` Khalid Aziz
2019-04-17 19:49 ` Andy Lutomirski
2019-04-17 19:52 ` Tycho Andersen
2019-04-17 20:12 ` Khalid Aziz
2019-05-01 14:49 ` Waiman Long
2019-05-01 15:18 ` Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 04/13] xpfo, x86: Add support for XPFO for x86-64 Khalid Aziz
2019-04-04 7:52 ` Peter Zijlstra
2019-04-04 15:40 ` Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 05/13] mm: add a user_virt_to_phys symbol Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 06/13] lkdtm: Add test for XPFO Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 07/13] arm64/mm: Add support " Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 08/13] swiotlb: Map the buffer if it was unmapped by XPFO Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 09/13] xpfo: add primitives for mapping underlying memory Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 10/13] arm64/mm, xpfo: temporarily map dcache regions Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 11/13] xpfo, mm: optimize spinlock usage in xpfo_kunmap Khalid Aziz
2019-04-04 7:56 ` Peter Zijlstra
2019-04-04 16:06 ` Khalid Aziz
2019-04-03 17:34 ` [RFC PATCH v9 12/13] xpfo, mm: Defer TLB flushes for non-current CPUs (x86 only) Khalid Aziz
2019-04-04 4:10 ` Andy Lutomirski
[not found] ` <91f1dbce-332e-25d1-15f6-0e9cfc8b797b@oracle.com>
2019-04-05 7:17 ` Thomas Gleixner
2019-04-05 14:44 ` Dave Hansen
2019-04-05 15:24 ` Andy Lutomirski
2019-04-05 15:56 ` Tycho Andersen
2019-04-05 16:32 ` Andy Lutomirski
2019-04-05 15:56 ` Khalid Aziz
2019-04-05 16:01 ` Dave Hansen
2019-04-05 16:27 ` Andy Lutomirski
2019-04-05 16:41 ` Peter Zijlstra
2019-04-05 17:35 ` Khalid Aziz
2019-04-05 15:44 ` Khalid Aziz
2019-04-05 15:24 ` Andy Lutomirski
2019-04-04 8:18 ` Peter Zijlstra
2019-04-03 17:34 ` [RFC PATCH v9 13/13] xpfo, mm: Optimize XPFO TLB flushes by batching them together Khalid Aziz
2019-04-04 16:44 ` [RFC PATCH v9 00/13] Add support for eXclusive Page Frame Ownership Nadav Amit
2019-04-04 17:18 ` Khalid Aziz
2019-04-06 6:40 ` Jon Masters
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