linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@linux.intel.com>, Sasha Levin <sashal@kernel.org>,
	linux-kernel@vger.kernel.org, bp@alien8.de, luto@kernel.org,
	hpa@zytor.com, dave.hansen@intel.com, tony.luck@intel.com,
	ravi.v.shankar@intel.com, chang.seok.bae@intel.com
Subject: Re: [PATCH v12 00/18] Enable FSGSBASE instructions
Date: Tue, 19 May 2020 19:48:53 +0300	[thread overview]
Message-ID: <20200519164853.GA19706@linux.intel.com> (raw)
In-Reply-To: <87v9ksvoaq.fsf@nanos.tec.linutronix.de>

On Tue, May 19, 2020 at 01:03:25AM +0200, Thomas Gleixner wrote:
> Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> writes:
> > On Mon, 2020-05-18 at 08:34 -0700, Andi Kleen wrote:
> >> > Yes, for SGX this is functional feature because enclave entry points,
> >> > thread control structures (aka TCS's), reset FSBASE and GSBASE registers
> >> > to fixed (albeit user defined) values. And syscall's can be done only
> >> > outside of enclave.
> >> > 
> >> > This is a required feature for fancier runtimes (such as Graphene).
> >> 
> >> Can you please explain a bit more? What do they need GS for?
> >
> > Apparently, uses only wrfsbase:
> >
> > https://raw.githubusercontent.com/oscarlab/graphene/master/Pal/src/host/Linux-SGX/db_misc.c
> >
> > I'm not too familiar with the codebase yet but by reading some research
> > papers in the past the idea is to multiplex one TCS for multiple virtual
> > threads inside the enclave.
> >
> > E.g. TCS could represent a vcpu for a libos type of container and on
> > entry would pick on a thread and set fsbase accordingly for a thread
> > control block.
> 
> That justifies to write books which recommend to load a kernel module
> which creates a full unpriviledged root hole. I bet none of these papers
> ever mentioned that.

Fully agree that oot lkm for this is a worst idea ever.

That's why I want to help with this.

/Jarkko

  reply	other threads:[~2020-05-19 16:49 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-11  4:52 [PATCH v12 00/18] Enable FSGSBASE instructions Sasha Levin
2020-05-11  4:52 ` [PATCH v12 01/18] x86/ptrace: Prevent ptrace from clearing the FS/GS selector Sasha Levin
2020-05-11  4:52 ` [PATCH v12 02/18] selftests/x86/fsgsbase: Test GS selector on ptracer-induced GS base write Sasha Levin
2020-05-11  4:52 ` [PATCH v12 03/18] x86/cpu: Add 'unsafe_fsgsbase' to enable CR4.FSGSBASE Sasha Levin
2020-05-11  4:52 ` [PATCH v12 04/18] x86/entry/64: Clean up paranoid exit Sasha Levin
2020-05-11  4:52 ` [PATCH v12 05/18] x86/entry/64: Switch CR3 before SWAPGS in paranoid entry Sasha Levin
2020-05-11  4:52 ` [PATCH v12 06/18] x86/entry/64: Introduce the FIND_PERCPU_BASE macro Sasha Levin
2020-05-11  4:53 ` [PATCH v12 07/18] x86/entry/64: Handle FSGSBASE enabled paranoid entry/exit Sasha Levin
2020-05-11  4:53 ` [PATCH v12 08/18] x86/entry/64: Document GSBASE handling in the paranoid path Sasha Levin
2020-05-11  4:53 ` [PATCH v12 09/18] x86/fsgsbase/64: Add intrinsics for FSGSBASE instructions Sasha Levin
2020-05-11  4:53 ` [PATCH v12 10/18] x86/fsgsbase/64: Enable FSGSBASE instructions in helper functions Sasha Levin
2020-05-18 18:20   ` Thomas Gleixner
2020-05-18 20:24     ` Sasha Levin
2020-05-18 22:59       ` Thomas Gleixner
2020-05-19 12:20       ` David Laight
2020-05-19 14:48         ` Thomas Gleixner
2020-05-20  9:13           ` David Laight
2020-05-11  4:53 ` [PATCH v12 11/18] x86/fsgsbase/64: Use FSGSBASE in switch_to() if available Sasha Levin
2020-05-11  4:53 ` [PATCH v12 12/18] x86/fsgsbase/64: move save_fsgs to header file Sasha Levin
2020-05-11  4:53 ` [PATCH v12 13/18] x86/fsgsbase/64: Use FSGSBASE instructions on thread copy and ptrace Sasha Levin
2020-05-11  4:53 ` [PATCH v12 14/18] x86/speculation/swapgs: Check FSGSBASE in enabling SWAPGS mitigation Sasha Levin
2020-05-11  4:53 ` [PATCH v12 15/18] selftests/x86/fsgsbase: Test ptracer-induced GS base write with FSGSBASE Sasha Levin
2020-05-11  4:53 ` [PATCH v12 16/18] x86/fsgsbase/64: Enable FSGSBASE on 64bit by default and add a chicken bit Sasha Levin
2020-05-11  4:53 ` [PATCH v12 17/18] x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2 Sasha Levin
2020-05-11  4:53 ` [PATCH v12 18/18] Documentation/x86/64: Add documentation for GS/FS addressing mode Sasha Levin
2020-05-15  9:24 ` [PATCH v12 00/18] Enable FSGSBASE instructions Jarkko Sakkinen
2020-05-15 16:40   ` Sasha Levin
2020-05-15 17:55     ` Andi Kleen
2020-05-15 23:07       ` Sasha Levin
2020-05-16 12:21       ` Jarkko Sakkinen
2020-05-16  9:50     ` Jarkko Sakkinen
2020-05-18 15:34       ` Andi Kleen
2020-05-18 20:01         ` Jarkko Sakkinen
2020-05-18 23:03           ` Thomas Gleixner
2020-05-19 16:48             ` Jarkko Sakkinen [this message]
2020-05-22 20:14               ` Don Porter
2020-05-22 20:55                 ` Dave Hansen
2020-05-23  0:45                 ` Thomas Gleixner
2020-05-24 19:45                   ` hpa
2020-05-24 21:19                     ` Sasha Levin
2020-05-24 23:44                       ` hpa
2020-05-25  7:54                       ` Richard Weinberger
2020-05-25 21:56                         ` Tony Luck
2020-05-26  8:12                         ` David Laight
2020-05-26  8:23                           ` Richard Weinberger
2020-05-27  8:31                     ` Jarkko Sakkinen
2020-05-26 12:42                   ` Don Porter
2020-05-26 20:27                     ` Sasha Levin
2020-05-26 22:03                       ` Don Porter
2020-05-26 22:51                         ` Sasha Levin
2020-05-28 17:37                           ` Don Porter
2020-05-28 10:29                     ` Thomas Gleixner
2020-05-28 17:40                       ` Don Porter
2020-05-28 18:38                         ` Andy Lutomirski
2020-05-29 15:27                           ` Wojtek Porczyk
2020-06-25 15:27                             ` Don Porter
2020-06-25 21:37                               ` Jarkko Sakkinen
2020-07-18 18:19                                 ` Don Porter
2020-07-23  3:23                                   ` Jarkko Sakkinen
2020-05-28 19:19                         ` Jarkko Sakkinen
2020-05-28 19:41                           ` Sasha Levin
2020-05-29  3:07                             ` Jarkko Sakkinen
2020-05-29  3:10                               ` Jarkko Sakkinen
2020-06-25 15:30                                 ` Don Porter
2020-06-25 21:40                                   ` Jarkko Sakkinen
2020-05-23  4:19                 ` Andi Kleen
2020-05-28 10:36                   ` Thomas Gleixner
2020-05-27  8:20                 ` Jarkko Sakkinen
2020-05-27 12:42                   ` Wojtek Porczyk
2020-05-18  9:51     ` Thomas Gleixner
2020-05-18 15:16       ` Sasha Levin
2020-05-18 18:28         ` Thomas Gleixner
2020-05-18 19:36       ` Jarkko Sakkinen
2020-05-18  6:18 ` Christoph Hellwig
2020-05-18 12:33   ` Sasha Levin
2020-05-18 14:53 ` Thomas Gleixner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200519164853.GA19706@linux.intel.com \
    --to=jarkko.sakkinen@linux.intel.com \
    --cc=ak@linux.intel.com \
    --cc=bp@alien8.de \
    --cc=chang.seok.bae@intel.com \
    --cc=dave.hansen@intel.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@kernel.org \
    --cc=ravi.v.shankar@intel.com \
    --cc=sashal@kernel.org \
    --cc=tglx@linutronix.de \
    --cc=tony.luck@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).