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From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: linux-integrity@vger.kernel.org, Mimi Zohar <zohar@linux.ibm.com>,
	David Woodhouse <dwmw2@infradead.org>,
	keyrings@vger.kernel.org
Subject: Re: [PATCH v5 3/6] security: keys: trusted fix tpm2 authorizations
Date: Wed, 26 Feb 2020 16:58:11 -0800	[thread overview]
Message-ID: <1582765091.4245.33.camel@HansenPartnership.com> (raw)
In-Reply-To: <20200225164850.GB15662@linux.intel.com>

On Tue, 2020-02-25 at 18:48 +0200, Jarkko Sakkinen wrote:
> On Thu, Jan 30, 2020 at 11:18:09AM +0100, James Bottomley wrote:
> > In TPM 1.2 an authorization was a 20 byte number.  The spec
> > actually recommended you to hash variable length passwords and use
> > the sha1 hash as the authorization.  Because the spec doesn't
> > require this hashing, the current authorization for trusted keys is
> > a 40 digit hex number.  For TPM 2.0 the spec allows the passing in
> > of variable length passwords and passphrases directly, so we should
> > allow that in trusted keys for ease of use.  Update the 'blobauth'
> > parameter to take this into account, so we can now use plain text
> > passwords for the keys.
> > 
> > so before
> > 
> > keyctl add trusted kmk "new 32
> > blobauth=f572d396fae9206628714fb2ce00f72e94f2258f"
> > 
> > after we will accept both the old hex sha1 form as well as a new
> > directly supplied password:
> > 
> > keyctl add trusted kmk "new 32 blobauth=hello keyhandle=81000001"
> > 
> > Since a sha1 hex code must be exactly 40 bytes long and a direct
> > password must be 20 or less, we use the length as the discriminator
> > for which form is input.
> > 
> > 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.
> > 
> > Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.c
> > om>
> 
> Should have a fixes tag.

I made all the other changes, but I'm not sure what to identify in the
fixes tag.  The problem is the code I updated was simply carried over
unaltered from TPM 1.2

You could certainly argue that commit

commit 0fe5480303a1657b328a0a389f8d99249d9961f5
Author: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Date:   Fri Jun 26 22:28:26 2015 +0300

    keys, trusted: seal/unseal with TPM 2.0 chips

Should have updated the blobauth handling ... is that the one you'd
like fixes: to identify?

James


  parent reply	other threads:[~2020-02-27  0:58 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-30 10:18 [PATCH v5 0/6] TPM 2.0 trusted keys with attached policy James Bottomley
2020-01-30 10:18 ` [PATCH v5 1/6] lib: add ASN.1 encoder James Bottomley
2020-01-30 10:18 ` [PATCH v5 2/6] oid_registry: Add TCG defined OIDS for TPM keys James Bottomley
2020-01-30 10:18 ` [PATCH v5 3/6] security: keys: trusted fix tpm2 authorizations James Bottomley
2020-02-25 16:48   ` Jarkko Sakkinen
2020-02-26 15:15     ` Jarkko Sakkinen
2020-02-27  0:58     ` James Bottomley [this message]
2020-02-27 16:19       ` Jarkko Sakkinen
2020-02-27 16:21         ` James Bottomley
2020-02-27 17:49           ` James Bottomley
2020-03-02 11:08             ` Jarkko Sakkinen
2020-01-30 10:18 ` [PATCH v5 4/6] security: keys: trusted: use ASN.1 TPM2 key format for the blobs James Bottomley
2020-02-03 16:54   ` James Prestwood
2020-02-27  0:02     ` James Bottomley
2020-02-27  0:20       ` James Prestwood
2020-02-27  0:54         ` James Bottomley
2020-02-27 17:19           ` James Prestwood
2020-02-27 20:19             ` James Bottomley
2020-02-27 20:26               ` James Bottomley
2020-02-27 20:44                 ` James Prestwood
2020-02-27 20:57               ` James Prestwood
2020-07-12 21:38                 ` Ken Goldman
2020-07-12 21:54                   ` James Bottomley
2020-03-02 19:00               ` James Prestwood
2020-01-30 10:18 ` [PATCH v5 5/6] security: keys: trusted: add ability to specify arbitrary policy James Bottomley
2020-01-30 10:18 ` [PATCH v5 6/6] security: keys: trusted: implement counter/timer policy James Bottomley
2020-02-20 20:17 ` [PATCH v5 0/6] TPM 2.0 trusted keys with attached policy Jarkko Sakkinen

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