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From: Matthew Garrett <mjg59@google.com>
To: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: David Tolnay <dtolnay@gmail.com>, Peter Huewe <peterhuewe@gmx.de>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	linux-integrity <linux-integrity@vger.kernel.org>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	virtualization@lists.linux-foundation.org, dgreid@chromium.org,
	apronin@chromium.org
Subject: Re: [PATCH] tpm: Add driver for TPM over virtio
Date: Mon, 25 Feb 2019 13:02:53 -0800	[thread overview]
Message-ID: <CACdnJutzRur52hbJ_Ckm64RPfuv5MrMBY3OwO1yM+QC8Ax_Rvw@mail.gmail.com> (raw)
In-Reply-To: <CACdnJuvObeL75p1Wb2qnTdt1gS28zCMvasogA9=2ksMv=fE82Q@mail.gmail.com>

On Mon, Feb 25, 2019 at 1:00 PM Matthew Garrett <mjg59@google.com> wrote:
> > I'm still looking for the pragmatic use case.  I think yours is attack
> > surface reduction, because the virtio discovery and operation is less
> > code and therefore more secure than physical hardware discovery and
> > operation?  I'm not entirely sure I buy that because the TPM
> > communication interface is pretty simple and it's fairly deep down in
> > the kernel internal stack making it difficult to exploit.
>
> Being able to get away without any LPC support code at all seems like
> a win, as does not having any ACPI or DeviceTree parsing code.
> Injecting the hardware information via the kernel command line isn't
> impossible, but it's not an attractive solution.

Oh, but to be clear - I think the bigger win is having a reduced
surface in the *hypervisor*, not the kernel. Just having enough
support to pass commands through to the vTPM is a lot easier than
emulating the whole hardware interface to the TPM (and see the number
of bugs in things like qemu's floppy drive emulation as an example of
how hard this can be to get right)

  reply	other threads:[~2019-02-25 21:03 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-22  2:14 [PATCH] tpm: Add driver for TPM over virtio David Tolnay
2019-02-22  5:51 ` Michael S. Tsirkin
2019-02-22  5:51   ` Michael S. Tsirkin
2019-02-22 21:40   ` David Tolnay
2019-02-22 22:24     ` Michael S. Tsirkin
2019-02-22 22:24       ` Michael S. Tsirkin
2019-02-23  1:23       ` David Tolnay
2019-02-25  9:58   ` Jarkko Sakkinen
2019-02-22 10:26 ` Jarkko Sakkinen
2019-02-22 15:23   ` Michael S. Tsirkin
2019-02-22 15:23     ` Michael S. Tsirkin
2019-02-22 19:31     ` Jarkko Sakkinen
2019-02-22 19:33       ` Jarkko Sakkinen
2019-02-22 21:25         ` Michael S. Tsirkin
2019-02-22 21:25           ` Michael S. Tsirkin
2019-02-22 21:50           ` Jarkko Sakkinen
2019-02-22 22:24             ` David Tolnay
2019-02-22 22:36               ` Jarkko Sakkinen
2019-02-22 23:05                 ` Michael S. Tsirkin
2019-02-22 23:05                   ` Michael S. Tsirkin
2019-02-24  9:33                   ` Jarkko Sakkinen
2019-02-22 20:55       ` Michael S. Tsirkin
2019-02-22 20:55         ` Michael S. Tsirkin
2019-02-22 21:30         ` Jarkko Sakkinen
2019-02-22 10:30 ` Jarkko Sakkinen
2019-02-22 15:30 ` James Bottomley
2019-02-22 21:16   ` Michael S. Tsirkin
2019-02-22 21:16     ` Michael S. Tsirkin
2019-02-22 21:31     ` Jason Gunthorpe
2019-02-22 21:59       ` Jarkko Sakkinen
2019-02-22 22:07         ` Michael S. Tsirkin
2019-02-22 22:07           ` Michael S. Tsirkin
2019-02-22 22:14           ` Jarkko Sakkinen
2019-02-22 22:00   ` David Tolnay
2019-02-22 22:18     ` James Bottomley
2019-02-23  0:45       ` David Tolnay
2019-02-23  1:34         ` James Bottomley
2019-02-23  2:41           ` David Tolnay
2019-02-24 16:30             ` James Bottomley
2019-02-24 17:51               ` Jarkko Sakkinen
2019-02-24 22:12               ` David Tolnay
2019-02-25  9:55                 ` Jarkko Sakkinen
2019-02-25 15:36                 ` James Bottomley
2019-02-25 19:17                   ` Matthew Garrett
2019-02-25 19:54                     ` Jarkko Sakkinen
2019-02-25 20:20                     ` James Bottomley
2019-02-25 21:00                       ` Matthew Garrett
2019-02-25 21:02                         ` Matthew Garrett [this message]
2019-02-25 22:14                         ` James Bottomley
2019-02-25 22:24                           ` Matthew Garrett
2019-02-25 22:32                             ` James Bottomley
2019-02-25 22:43                               ` Matthew Garrett
2019-02-25 22:51                                 ` James Bottomley
2019-02-25 23:02                                   ` Matthew Garrett
2019-02-25 23:09                                     ` James Bottomley
2019-02-25 21:05                       ` Jarkko Sakkinen
2019-02-25 22:24                         ` James Bottomley

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