From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Jarkko Sakkinen <jarkko@kernel.org>,
Lino Sanfilippo <l.sanfilippo@kunbus.com>,
Alexander Steffen <Alexander.Steffen@infineon.com>,
"Daniel P. Smith" <dpsmith@apertussolutions.com>,
Jason Gunthorpe <jgg@ziepe.ca>, Sasha Levin <sashal@kernel.org>,
linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Ross Philipson <ross.philipson@oracle.com>,
Kanth Ghatraju <kanth.ghatraju@oracle.com>,
Peter Huewe <peterhuewe@gmx.de>
Subject: Re: [PATCH 1/3] tpm: protect against locality counter underflow
Date: Wed, 21 Feb 2024 07:37:01 -0500 [thread overview]
Message-ID: <7a7f8f0c1b9d124bfc01b66082abf2d8445564ce.camel@HansenPartnership.com> (raw)
In-Reply-To: <CZA9GMC718HA.1JFHTTWV563IE@seitikki>
On Tue, 2024-02-20 at 22:31 +0000, Jarkko Sakkinen wrote:
>
> 2. Because localities are not too useful these days given TPM2's
> policy mechanism
Localitites are useful to the TPM2 policy mechanism. When we get key
policy in the kernel it will give us a way to create TPM wrapped keys
that can only be unwrapped in the kernel if we run the kernel in a
different locality from userspace (I already have demo patches doing
this).
> I cannot recall out of top of my head can
> you have two localities open at same time.
I think there's a misunderstanding about what localities are: they're
effectively an additional platform supplied tag to a command. Each
command can therefore have one and only one locality. The TPM doesn't
have a concept of which locality is open; if you look at the reference
implementation, the simulator has a __plat__LocalitySet() function
which places all commands in the just set locality until you change to
a different one.
However, since the way localities are implemented (i.e. what triggers
_plat__LocalitySet()) is implementation defined, each physical TPM
device has a different way of doing the set (for instance, for TIS
TPM's locality is a function of the port set used to address the TPM;
for CRB TPMs it can be an additional tag on the buffer for command
submission). I think the locality request/relinquish was modelled
after some other HW, but I don't know what.
James
next prev parent reply other threads:[~2024-02-21 12:37 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240131170824.6183-1-dpsmith@apertussolutions.com>
2024-01-31 17:08 ` [PATCH 1/3] tpm: protect against locality counter underflow Daniel P. Smith
2024-02-01 22:21 ` Jarkko Sakkinen
2024-02-02 3:08 ` Lino Sanfilippo
2024-02-12 20:05 ` Jarkko Sakkinen
2024-02-19 17:54 ` Daniel P. Smith
2024-02-20 18:42 ` Alexander Steffen
2024-02-20 19:04 ` Jarkko Sakkinen
2024-02-20 20:54 ` Lino Sanfilippo
2024-02-20 22:23 ` Jarkko Sakkinen
2024-02-20 23:19 ` Lino Sanfilippo
2024-02-21 0:40 ` Jarkko Sakkinen
2024-02-23 1:58 ` Daniel P. Smith
2024-02-23 12:58 ` Jarkko Sakkinen
2024-02-25 11:23 ` Daniel P. Smith
2024-02-26 9:39 ` Jarkko Sakkinen
2024-02-20 22:26 ` Jarkko Sakkinen
2024-02-20 22:31 ` Jarkko Sakkinen
2024-02-20 23:26 ` Lino Sanfilippo
2024-02-21 0:42 ` Jarkko Sakkinen
2024-02-21 12:37 ` James Bottomley [this message]
2024-02-21 19:43 ` Jarkko Sakkinen
2024-02-21 19:45 ` Jarkko Sakkinen
2024-02-22 9:06 ` James Bottomley
2024-02-22 23:49 ` Jarkko Sakkinen
2024-02-23 1:57 ` Daniel P. Smith
2024-02-23 20:40 ` Jarkko Sakkinen
2024-02-23 20:42 ` Jarkko Sakkinen
2024-02-23 1:57 ` Daniel P. Smith
2024-02-23 20:50 ` Jarkko Sakkinen
2024-02-20 22:57 ` ross.philipson
2024-02-20 23:10 ` Jarkko Sakkinen
2024-02-20 23:13 ` Jarkko Sakkinen
2024-02-23 1:56 ` Daniel P. Smith
2024-02-23 20:44 ` Jarkko Sakkinen
2024-02-24 2:34 ` Lino Sanfilippo
2024-02-26 9:38 ` Jarkko Sakkinen
2024-02-23 1:55 ` Daniel P. Smith
2024-02-26 12:43 ` Alexander Steffen
2024-02-24 2:06 ` Lino Sanfilippo
2024-02-23 0:01 ` Jarkko Sakkinen
2024-01-31 17:08 ` [PATCH 2/3] tpm: ensure tpm is in known state at startup Daniel P. Smith
2024-02-01 22:33 ` Jarkko Sakkinen
2024-02-19 19:17 ` Daniel P. Smith
2024-02-19 20:17 ` Jarkko Sakkinen
2024-01-31 17:08 ` [PATCH 3/3] tpm: make locality request return value consistent Daniel P. Smith
2024-02-01 22:49 ` Jarkko Sakkinen
2024-02-19 20:29 ` Daniel P. Smith
2024-02-19 20:45 ` Jarkko Sakkinen
2024-02-20 18:57 ` Alexander Steffen
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