From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Tadeusz Struk <tadeusz.struk@intel.com>, jarkko.sakkinen@linux.intel.com
Cc: peterz@infradead.org, linux-kernel@vger.kernel.org, jgg@ziepe.ca,
mingo@redhat.com, jeffrin@rajagiritech.edu.in,
linux-integrity@vger.kernel.org, will@kernel.org,
peterhuewe@gmx.de
Subject: Re: [PATCH =v2 3/3] tpm: selftest: cleanup after unseal with wrong auth/policy test
Date: Thu, 12 Dec 2019 15:54:45 -0500 [thread overview]
Message-ID: <1576184085.10287.13.camel@HansenPartnership.com> (raw)
In-Reply-To: <c3bffb8c-d454-1f53-7f7e-8b65884ffaf6@intel.com>
On Thu, 2019-12-12 at 12:49 -0800, Tadeusz Struk wrote:
> On 12/12/19 11:51 AM, James Bottomley wrote:
> > TPM2_Clear reprovisions the SPS ... that would make all currently
> > exported TPM keys go invalid. I know these tests should be
> > connected to a vTPM, so doing this should be safe, but if this
> > accidentally got executed on your laptop all TPM relying functions
> > would be disrupted, which doesn't seem to be the best thing to hard
> > wire into a test.
>
> That is true, but it will need to be executed as root, and root
> should know what she/he is doing ;)
Not in the modern kernel resource manager world: anyone who is in the
tpm group can access the tpmrm device and we haven't added a dangerous
command filter like we promised we would, so unless they have actually
set lockout or platform authorization, they'll find they can execute it
> > What about doing a TPM2_DictionaryAttackLockReset instead, which is
> > the least invasive route to fixing the problem ... provided you
> > know what the lockout authorization is.
>
> I can change tpm2_clear to tpm2_dictionarylockout -c if we want to
> make it foolproof. In this case we can assume that the lockout auth
> is empty.
Well, if it isn't TPM2_Clear would refuse to execute as well since that
requires either lockout auth or platform + physical presence.
James
next prev parent reply other threads:[~2019-12-12 20:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-12 17:48 [PATCH =v2 1/3] tpm: fix invalid locking in NONBLOCKING mode Tadeusz Struk
2019-12-12 17:48 ` [PATCH =v2 2/3] tpm: selftest: add test covering async mode Tadeusz Struk
2019-12-17 1:55 ` Jarkko Sakkinen
2019-12-12 17:48 ` [PATCH =v2 3/3] tpm: selftest: cleanup after unseal with wrong auth/policy test Tadeusz Struk
2019-12-12 19:51 ` James Bottomley
2019-12-12 20:49 ` Tadeusz Struk
2019-12-12 20:54 ` James Bottomley [this message]
2019-12-12 21:07 ` Tadeusz Struk
2019-12-12 21:11 ` James Bottomley
2019-12-17 10:37 ` Jarkko Sakkinen
2019-12-17 1:32 ` [PATCH =v2 1/3] tpm: fix invalid locking in NONBLOCKING mode Jarkko Sakkinen
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