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From: "Stephen Röttger" <sroettger@google.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: jeffxu@chromium.org, luto@kernel.org, jorgelo@chromium.org,
	keescook@chromium.org, groeck@chromium.org, jannh@google.com,
	akpm@linux-foundation.org, jeffxu@google.com,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-mm@kvack.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH 0/6] Memory Mapping (VMA) protection using PKU - set 1
Date: Tue, 16 May 2023 09:06:32 +0200	[thread overview]
Message-ID: <CAEAAPHYdRyZEMp97919errF7SDuYBJoSrD5i1wrTx1sMdr_ZdQ@mail.gmail.com> (raw)
In-Reply-To: <2bcffc9f-9244-0362-2da9-ece230055320@intel.com>

[-- Attachment #1: Type: text/plain, Size: 1249 bytes --]

On Mon, May 15, 2023 at 4:28 PM Dave Hansen <dave.hansen@intel.com> wrote:
>
> On 5/15/23 06:05, jeffxu@chromium.org wrote:
> > We're using PKU for in-process isolation to enforce control-flow integrity
> > for a JIT compiler. In our threat model, an attacker exploits a
> > vulnerability and has arbitrary read/write access to the whole process
> > space concurrently to other threads being executed. This attacker can
> > manipulate some arguments to syscalls from some threads.
>
> This all sounds like it hinges on the contents of PKRU in the attacker
> thread.
>
> Could you talk a bit about how the attacker is prevented from running
> WRPKRU, XRSTOR or compelling the kernel to write to PKRU like at sigreturn?

(resending without html)

Since we're using the feature for control-flow integrity, we assume
the control-flow is still intact at this point. I.e. the attacker
thread can't run arbitrary instructions.
* For JIT code, we're going to scan it for wrpkru instructions before
writing it to executable memory
* For regular code, we only use wrpkru around short critical sections
to temporarily enable write access

Sigreturn is a separate problem that we hope to solve by adding pkey
support to sigaltstack

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  reply	other threads:[~2023-05-16  7:06 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-15 13:05 [PATCH 0/6] Memory Mapping (VMA) protection using PKU - set 1 jeffxu
2023-05-15 13:05 ` [PATCH 1/6] PKEY: Introduce PKEY_ENFORCE_API flag jeffxu
2023-05-16 23:14   ` Dave Hansen
2023-05-16 23:55     ` Jeff Xu
2023-05-17 11:07     ` Stephen Röttger
2023-05-15 13:05 ` [PATCH 2/6] PKEY: Add arch_check_pkey_enforce_api() jeffxu
2023-05-18 21:43   ` Dave Hansen
2023-05-18 22:51     ` Jeff Xu
2023-05-19  0:00       ` Dave Hansen
2023-05-19 11:22         ` Stephen Röttger
2023-05-15 13:05 ` [PATCH 3/6] PKEY: Apply PKEY_ENFORCE_API to mprotect jeffxu
2023-05-16 20:07   ` Kees Cook
2023-05-16 22:23     ` Jeff Xu
2023-05-16 23:18   ` Dave Hansen
2023-05-16 23:36     ` Jeff Xu
2023-05-17  4:50       ` Jeff Xu
2023-05-15 13:05 ` [PATCH 4/6] PKEY:selftest pkey_enforce_api for mprotect jeffxu
2023-05-15 13:05 ` [PATCH 5/6] KEY: Apply PKEY_ENFORCE_API to munmap jeffxu
2023-05-16 20:06   ` Kees Cook
2023-05-16 22:24     ` Jeff Xu
2023-05-16 23:23   ` Dave Hansen
2023-05-17  0:08     ` Jeff Xu
2023-05-15 13:05 ` [PATCH 6/6] PKEY:selftest pkey_enforce_api for munmap jeffxu
2023-05-15 14:28 ` [PATCH 0/6] Memory Mapping (VMA) protection using PKU - set 1 Dave Hansen
2023-05-16  7:06   ` Stephen Röttger [this message]
2023-05-16 22:41     ` Dave Hansen
2023-05-17 10:51       ` Stephen Röttger
2023-05-17 15:07         ` Dave Hansen
2023-05-17 15:21           ` Jeff Xu
2023-05-17 15:29             ` Dave Hansen
2023-05-17 23:48               ` Jeff Xu
2023-05-18 15:37                 ` Dave Hansen
2023-05-18 20:20                   ` Jeff Xu
2023-05-18 21:04                     ` Dave Hansen
2023-05-19 11:13                       ` Stephen Röttger
2023-05-24 20:15                       ` Jeff Xu
2023-06-01  1:39                       ` Jeff Xu
2023-06-01 16:16                         ` Dave Hansen
2023-05-31 23:02                   ` Jeff Xu
2023-05-16 20:08 ` Kees Cook
2023-05-16 22:17   ` Jeff Xu
2023-05-16 22:30     ` Dave Hansen
2023-05-16 23:39       ` Jeff Xu
2023-05-17 10:49   ` Stephen Röttger

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