From: Samuel Ortiz <sameo@rivosinc.com>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lukas Wunner <lukas@wunner.de>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Reshetova, Elena" <elena.reshetova@intel.com>,
"Shishkin, Alexander" <alexander.shishkin@intel.com>,
"Shutemov, Kirill" <kirill.shutemov@intel.com>,
"Kuppuswamy,
Sathyanarayanan" <sathyanarayanan.kuppuswamy@intel.com>,
"Kleen, Andi" <andi.kleen@intel.com>,
"Hansen, Dave" <dave.hansen@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
"Poimboe, Josh" <jpoimboe@redhat.com>,
"aarcange@redhat.com" <aarcange@redhat.com>,
Cfir Cohen <cfir@google.com>, Marc Orr <marcorr@google.com>,
"jbachmann@google.com" <jbachmann@google.com>,
"pgonda@google.com" <pgonda@google.com>,
"keescook@chromium.org" <keescook@chromium.org>,
James Morris <jmorris@namei.org>,
Michael Kelley <mikelley@microsoft.com>,
"Lange, Jon" <jlange@microsoft.com>,
"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-pci@vger.kernel.org
Subject: Re: Linux guest kernel threat model for Confidential Computing
Date: Fri, 27 Jan 2023 08:02:16 +0100 [thread overview]
Message-ID: <Y9N2+Bsm0xLbLg5q@vermeer> (raw)
In-Reply-To: <20230126160729.00006843@Huawei.com>
On Thu, Jan 26, 2023 at 04:07:29PM +0000, Jonathan Cameron wrote:
> On Thu, 26 Jan 2023 14:15:05 +0100
> Samuel Ortiz <sameo@rivosinc.com> wrote:
>
> > On Thu, Jan 26, 2023 at 10:58:47AM +0000, Jonathan Cameron wrote:
> > > On Thu, 26 Jan 2023 10:24:32 +0100
> > > Samuel Ortiz <sameo@rivosinc.com> wrote:
> > >
> > > > Hi Lukas,
> > > >
> > > > On Wed, Jan 25, 2023 at 11:03 PM Lukas Wunner <lukas@wunner.de> wrote:
> > > >
> > > > > [cc += Jonathan Cameron, linux-pci]
> > > > >
> > > > > On Wed, Jan 25, 2023 at 02:57:40PM +0000, Dr. David Alan Gilbert wrote:
> > > > > > Greg Kroah-Hartman (gregkh@linuxfoundation.org) wrote:
> > > > > > > Great, so why not have hardware attestation also for your devices you
> > > > > > > wish to talk to? Why not use that as well? Then you don't have to
> > > > > > > worry about anything in the guest.
> > > > > >
> > > > > > There were some talks at Plumbers where PCIe is working on adding that;
> > > > > > it's not there yet though. I think that's PCIe 'Integrity and Data
> > > > > > Encryption' (IDE - sigh), and PCIe 'Security Prtocol and Data Model' -
> > > > > > SPDM. I don't know much of the detail of those, just that they're far
> > > > > > enough off that people aren't depending on them yet.
> > > > >
> > > > > CMA/SPDM (PCIe r6.0 sec 6.31) is in active development on this branch:
> > > > >
> > > > > https://github.com/l1k/linux/commits/doe
> > > >
> > > > Nice, thanks a lot for that.
> > > >
> > > >
> > > >
> > > > > The device authentication service afforded here is generic.
> > > > > It is up to users and vendors to decide how to employ it,
> > > > > be it for "confidential computing" or something else.
> > > > >
> > > > > Trusted root certificates to validate device certificates can be
> > > > > installed into a kernel keyring using the familiar keyctl(1) utility,
> > > > > but platform-specific roots of trust (such as a HSM) could be
> > > > > supported as well.
> > > > >
> > > >
> > > > This may have been discussed at LPC, but are there any plans to also
> > > > support confidential computing flows where the host kernel is not part
> > > > of the TCB and would not be trusted for validating the device cert chain
> > > > nor for running the SPDM challenge?
> > >
> > > There are lots of possible models for this. One simple option if the assigned
> > > VF supports it is a CMA instance per VF. That will let the guest
> > > do full attestation including measurement of whether the device is
> > > appropriately locked down so the hypervisor can't mess with
> > > configuration that affects the guest (without a reset anyway and that
> > > is guest visible).
> >
> > So the VF would be directly assigned to the guest, and the guest kernel
> > would create a CMA instance for the VF, and do the SPDM authentication
> > (based on a guest provided trusted root certificate). I think one
> > security concern with that approach is assigning the VF to the
> > (potentially confidential) guest address space without the guest being
> > able to attest of the device trustworthiness first. That's what TDISP is
> > aiming at fixing (establish a secure SPDM between the confidential guest
> > and the device, lock the device from the guest, attest and then enable
> > DMA).
>
> Agreed, TDISP is more comprehensive, but also much more complex with
> more moving parts that we don't really have yet.
>
> Depending on your IOMMU design (+ related stuff) and interaction with
> the secure guest, you might be able to block any rogue DMA until
> after attestation / lock down checks even if the Hypervisor was letting
> it through.
Provided that the guest or, in the TDX and AP-TEE cases, the TSM have
protected access to the IOMMU, yes. But then the implementation becomes
platform specific.
Cheers,
Samuel.
next prev parent reply other threads:[~2023-01-27 7:02 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-25 12:28 Linux guest kernel threat model for Confidential Computing Reshetova, Elena
2023-01-25 12:43 ` Greg Kroah-Hartman
2023-01-25 13:42 ` Dr. David Alan Gilbert
2023-01-25 14:13 ` Daniel P. Berrangé
2023-01-25 15:29 ` Dr. David Alan Gilbert
2023-01-26 14:23 ` Richard Weinberger
2023-01-26 14:58 ` Dr. David Alan Gilbert
2023-01-26 15:13 ` Richard Weinberger
2023-01-26 15:22 ` Dr. David Alan Gilbert
2023-01-26 15:55 ` Daniel P. Berrangé
2023-01-27 9:02 ` Jörg Rödel
2023-01-26 15:43 ` Daniel P. Berrangé
2023-01-27 11:23 ` Reshetova, Elena
2023-01-30 11:30 ` Christophe de Dinechin
2023-01-25 14:22 ` Greg Kroah-Hartman
2023-01-25 14:30 ` James Bottomley
2023-01-25 14:57 ` Dr. David Alan Gilbert
2023-01-25 15:16 ` Greg Kroah-Hartman
2023-01-25 15:45 ` Michael S. Tsirkin
2023-01-25 16:02 ` Kirill A. Shutemov
2023-01-25 17:47 ` Michael S. Tsirkin
2023-01-25 15:50 ` Dr. David Alan Gilbert
2023-01-25 18:47 ` Jiri Kosina
2023-01-26 9:19 ` Jörg Rödel
2023-01-25 21:53 ` Lukas Wunner
2023-01-26 10:48 ` Dr. David Alan Gilbert
2023-01-26 11:24 ` Jonathan Cameron
2023-01-26 13:32 ` Samuel Ortiz
[not found] ` <CAGXJix9-cXNW7EwJf0PVzj_Qmt5fmQvBX1KvXfRX5NAeEpnMvw@mail.gmail.com>
2023-01-26 10:58 ` Jonathan Cameron
2023-01-26 13:15 ` Samuel Ortiz
2023-01-26 16:07 ` Jonathan Cameron
2023-01-27 7:02 ` Samuel Ortiz [this message]
2023-01-26 15:44 ` Lukas Wunner
2023-01-26 16:25 ` Michael S. Tsirkin
2023-01-26 21:41 ` Lukas Wunner
2023-01-27 7:17 ` Samuel Ortiz
2023-01-25 20:13 ` Jiri Kosina
2023-01-26 13:13 ` Reshetova, Elena
2023-01-25 15:29 ` Reshetova, Elena
2023-01-25 16:40 ` Theodore Ts'o
2023-01-26 8:08 ` Reshetova, Elena
2023-01-26 11:19 ` Leon Romanovsky
2023-01-26 11:29 ` Reshetova, Elena
2023-01-26 12:30 ` Leon Romanovsky
2023-01-26 13:28 ` Reshetova, Elena
2023-01-26 13:50 ` Leon Romanovsky
2023-01-26 20:54 ` Theodore Ts'o
2023-01-27 19:24 ` James Bottomley
2023-01-30 7:42 ` Reshetova, Elena
2023-01-30 12:40 ` James Bottomley
2023-01-31 11:31 ` Reshetova, Elena
2023-01-31 13:28 ` James Bottomley
2023-01-31 15:14 ` Christophe de Dinechin
2023-01-31 17:39 ` Michael S. Tsirkin
2023-02-01 10:52 ` Christophe de Dinechin Dupont de Dinechin
2023-02-01 11:01 ` Michael S. Tsirkin
2023-02-01 13:15 ` Christophe de Dinechin Dupont de Dinechin
2023-02-01 16:02 ` Michael S. Tsirkin
2023-02-01 17:13 ` Christophe de Dinechin
2023-02-06 18:58 ` Dr. David Alan Gilbert
2023-02-02 3:24 ` Jason Wang
2023-02-01 10:24 ` Christophe de Dinechin
2023-01-31 16:34 ` Reshetova, Elena
2023-01-31 17:49 ` James Bottomley
2023-02-02 14:51 ` Jeremi Piotrowski
2023-02-03 14:05 ` Reshetova, Elena
2023-01-27 9:32 ` Jörg Rödel
2023-01-26 13:58 ` Dr. David Alan Gilbert
2023-01-26 17:48 ` Reshetova, Elena
2023-01-26 18:06 ` Leon Romanovsky
2023-01-26 18:14 ` Dr. David Alan Gilbert
2023-01-26 16:29 ` Michael S. Tsirkin
2023-01-27 8:52 ` Reshetova, Elena
2023-01-27 10:04 ` Michael S. Tsirkin
2023-01-27 12:25 ` Reshetova, Elena
2023-01-27 14:32 ` Michael S. Tsirkin
2023-01-27 20:51 ` Carlos Bilbao
2023-01-30 11:36 ` Christophe de Dinechin
2023-01-30 12:00 ` Kirill A. Shutemov
2023-01-30 15:14 ` Michael S. Tsirkin
2023-01-31 10:06 ` Reshetova, Elena
2023-01-31 16:52 ` Christophe de Dinechin
2023-02-02 11:31 ` Reshetova, Elena
2023-02-07 0:27 ` Carlos Bilbao
2023-02-07 6:03 ` Greg Kroah-Hartman
2023-02-07 19:53 ` Carlos Bilbao
2023-02-07 21:55 ` Michael S. Tsirkin
2023-02-08 1:51 ` Theodore Ts'o
2023-02-08 9:31 ` Michael S. Tsirkin
2023-02-08 10:44 ` Reshetova, Elena
2023-02-08 10:58 ` Greg Kroah-Hartman
2023-02-08 16:19 ` Christophe de Dinechin
2023-02-08 17:29 ` Greg Kroah-Hartman
2023-02-08 18:02 ` Dr. David Alan Gilbert
2023-02-08 18:58 ` Thomas Gleixner
2023-02-09 19:48 ` Dr. David Alan Gilbert
2023-02-08 13:00 ` Michael S. Tsirkin
2023-02-08 13:42 ` Theodore Ts'o
2023-02-08 7:19 ` Greg Kroah-Hartman
2023-02-08 10:16 ` Reshetova, Elena
2023-02-08 13:15 ` Michael S. Tsirkin
2023-02-09 14:30 ` Reshetova, Elena
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=Y9N2+Bsm0xLbLg5q@vermeer \
--to=sameo@rivosinc.com \
--cc=Jonathan.Cameron@huawei.com \
--cc=aarcange@redhat.com \
--cc=alexander.shishkin@intel.com \
--cc=andi.kleen@intel.com \
--cc=cfir@google.com \
--cc=dave.hansen@intel.com \
--cc=dgilbert@redhat.com \
--cc=elena.reshetova@intel.com \
--cc=gregkh@linuxfoundation.org \
--cc=jasowang@redhat.com \
--cc=jbachmann@google.com \
--cc=jlange@microsoft.com \
--cc=jmorris@namei.org \
--cc=jpoimboe@redhat.com \
--cc=keescook@chromium.org \
--cc=kirill.shutemov@intel.com \
--cc=linux-coco@lists.linux.dev \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=lukas@wunner.de \
--cc=marcorr@google.com \
--cc=mika.westerberg@linux.intel.com \
--cc=mikelley@microsoft.com \
--cc=mst@redhat.com \
--cc=peterz@infradead.org \
--cc=pgonda@google.com \
--cc=sathyanarayanan.kuppuswamy@intel.com \
--cc=tglx@linutronix.de \
/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).