From: Ken Goldman <kgold@linux.ibm.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>,
linux-integrity@vger.kernel.org
Cc: Mimi Zohar <zohar@linux.ibm.com>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
David Woodhouse <dwmw2@infradead.org>,
keyrings@vger.kernel.org, David Howells <dhowells@redhat.com>
Subject: Re: [PATCH v14 3/5] security: keys: trusted: fix TPM2 authorizations
Date: Tue, 22 Dec 2020 18:01:46 -0500 [thread overview]
Message-ID: <dfd33d3d-8e1c-8acf-a3aa-3b62659d5d68@linux.ibm.com> (raw)
In-Reply-To: <20201129222004.4428-4-James.Bottomley@HansenPartnership.com>
On 11/29/2020 5:20 PM, James Bottomley wrote:
>
> Note this is both and enhancement and a potential bug fix. The TPM
> 2.0 spec requires us to strip leading zeros, meaning empyty
> authorization is a zero length HMAC whereas we're currently passing in
> 20 bytes of zeros. A lot of TPMs simply accept this as OK, but the
> Microsoft TPM emulator rejects it with TPM_RC_BAD_AUTH, so this patch
> makes the Microsoft TPM emulator work with trusted keys.
1 - To be precise, it strips trailing zeros, but 20 bytes of zero
results in an empty buffer either way.
"
Part 1 19.6.4.3 Authorization Size Convention
Trailing octets of zero are to be removed from any string before it is used as an authValue.
"
2 - If you have a test case for the MS simulator, post it and I'll give it a try.
I did a quick test, power cycle to set platform auth to empty, than
create primary with a parent password 20 bytes of zero, and the
SW TPM accepted it.
This was a password session, not an HMAC session.
next prev parent reply other threads:[~2020-12-22 23:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-29 22:19 [PATCH v14 0/5] TPM 2.0 trusted key rework James Bottomley
2020-11-29 22:20 ` [PATCH v14 1/5] lib: add ASN.1 encoder James Bottomley
2020-12-04 4:43 ` Jarkko Sakkinen
2020-12-04 4:44 ` Jarkko Sakkinen
2020-11-29 22:20 ` [PATCH v14 2/5] oid_registry: Add TCG defined OIDS for TPM keys James Bottomley
2020-11-29 22:20 ` [PATCH v14 3/5] security: keys: trusted: fix TPM2 authorizations James Bottomley
2020-12-22 23:01 ` Ken Goldman [this message]
2020-12-23 19:58 ` James Bottomley
2021-01-04 21:56 ` Jarkko Sakkinen
2020-11-29 22:20 ` [PATCH v14 4/5] security: keys: trusted: use ASN.1 TPM2 key format for the blobs James Bottomley
2020-11-30 2:10 ` kernel test robot
2020-11-30 19:58 ` James Bottomley
2020-12-04 4:49 ` Jarkko Sakkinen
2020-12-04 4:50 ` Jarkko Sakkinen
2020-12-07 16:23 ` James Bottomley
2020-12-08 11:02 ` Jarkko Sakkinen
2020-11-29 22:20 ` [PATCH v14 5/5] security: keys: trusted: Make sealed key properly interoperable James Bottomley
2020-12-04 13:40 ` [PATCH v14 1/5] lib: add ASN.1 encoder David Howells
2020-12-04 13:44 ` [PATCH v14 2/5] oid_registry: Add TCG defined OIDS for TPM keys David Howells
2020-12-04 16:01 ` James Bottomley
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