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From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Matthew Garrett <matthewgarrett@google.com>,
	linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org,
	linux-pm@vger.kernel.org, keyrings@vger.kernel.org,
	zohar@linux.ibm.com, jejb@linux.ibm.com, corbet@lwn.net,
	rjw@rjwysocki.net, Matthew Garrett <mjg59@google.com>
Subject: Re: [PATCH 5/9] security: keys: trusted: Allow storage of PCR values in creation data
Date: Mon, 22 Feb 2021 07:41:10 +0000	[thread overview]
Message-ID: <20210222074110.GC30403@codon.org.uk> (raw)
In-Reply-To: <YDB9U2oyt0fmvLDF@kernel.org>

On Sat, Feb 20, 2021 at 05:09:07AM +0200, Jarkko Sakkinen wrote:

> Something popped into mind: could we make PCR 23 reservation dynamic
> instead of a config option.
>
> E.g. if the user space uses it, then it's dirty and hibernate will
> fail. I really dislike the static compilation time firewall on it.

We can fail hibernation if userland hasn't flagged things, but the
concern is that if you hibernate with PCR 23 blocking enabled and then
reboot with the blocking disabled, userland can obtain the blob from the
hibernation image, extend PCR 23, modify the image and use the key
they've recovered to make it look legitimate, enable PCR 23 blocking
again and then resume into their own code.

  parent reply	other threads:[~2021-02-22  7:42 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-20  1:32 [PATCH 0/9] Enable hibernation when Lockdown is enabled Matthew Garrett
2021-02-20  1:32 ` [PATCH 1/9] tpm: Add support for in-kernel resetting of PCRs Matthew Garrett
2021-02-20  2:52   ` Jarkko Sakkinen
2021-02-20  1:32 ` [PATCH 2/9] tpm: Allow PCR 23 to be restricted to kernel-only use Matthew Garrett
2021-02-20  3:02   ` Jarkko Sakkinen
2021-02-24 17:12   ` Jarkko Sakkinen
2021-02-24 18:00   ` James Bottomley
2021-02-28  7:59     ` Matthew Garrett
2021-02-20  1:32 ` [PATCH 3/9] security: keys: trusted: Parse out individual components of the key blob Matthew Garrett
2021-02-20  3:05   ` Jarkko Sakkinen
2021-02-22  7:36     ` Matthew Garrett
2021-02-24 17:22       ` Jarkko Sakkinen
2021-02-20  1:32 ` [PATCH 4/9] security: keys: trusted: Store the handle of a loaded key Matthew Garrett
2021-02-20  3:06   ` Jarkko Sakkinen
2021-02-20  1:32 ` [PATCH 5/9] security: keys: trusted: Allow storage of PCR values in creation data Matthew Garrett
2021-02-20  3:09   ` Jarkko Sakkinen
2021-02-21 19:44     ` Ben Boeckel
2021-02-22  7:41     ` Matthew Garrett [this message]
2021-02-20  1:32 ` [PATCH 6/9] pm: hibernate: Optionally store and verify a hash of the image Matthew Garrett
2021-05-05 18:18   ` Evan Green
2021-02-20  1:32 ` [PATCH 7/9] pm: hibernate: Optionally use TPM-backed keys to protect image integrity Matthew Garrett
2021-02-20  2:20   ` Randy Dunlap
2021-02-22  7:41     ` Matthew Garrett
2021-02-20  1:32 ` [PATCH 8/9] pm: hibernate: Verify the digest encryption key Matthew Garrett
2021-02-20  1:32 ` [PATCH 9/9] pm: hibernate: seal the encryption key with a PCR policy Matthew Garrett
2021-05-04 21:56 ` [PATCH 0/9] Enable hibernation when Lockdown is enabled Evan Green
2021-05-05  3:18   ` Jarkko Sakkinen
2021-05-05  3:19     ` Jarkko Sakkinen
2021-05-05 18:02       ` Evan Green

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