From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
linux-integrity@vger.kernel.org
Cc: Mimi Zohar <zohar@linux.ibm.com>,
David Woodhouse <dwmw2@infradead.org>,
keyrings@vger.kernel.org, David Howells <dhowells@redhat.com>
Subject: Re: [PATCH v9 3/8] security: keys: trusted: fix TPM2 authorizations
Date: Wed, 13 May 2020 18:41:09 -0700 [thread overview]
Message-ID: <1589420469.9117.12.camel@HansenPartnership.com> (raw)
In-Reply-To: <664f00cf18c68e3f6316b50679b2fd56919d5aeb.camel@linux.intel.com>
On Thu, 2020-05-14 at 04:12 +0300, Jarkko Sakkinen wrote:
> On Thu, 2020-05-14 at 04:11 +0300, Jarkko Sakkinen wrote:
> > On Thu, 2020-05-07 at 16:11 -0700, 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.
> > >
> > > Fixes: 0fe5480303a1 ("keys, trusted: seal/unseal with TPM 2.0
> > > chips")
> > > Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership
> > > .com>
> > > Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> >
> > Have not checked yet the tail. Probably won't check before PR for
> > v5.8 is out.
> >
> > Just wondering would it hurt to merge everything up until this
> > patch?
Everything would be OK if you applied 1, 2 and 3. Except we'd have an
ASN.1 API in the tree with no consumers, which excites some people.
> I.e. could land it also to the release.
That would likely be fine and should satisfy the API with no consumers
issue.
James
next prev parent reply other threads:[~2020-05-14 1:41 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 23:11 [PATCH v9 0/8] TPM 2.0 trusted keys with attached policy James Bottomley
2020-05-07 23:11 ` [PATCH v9 1/8] lib: add ASN.1 encoder James Bottomley
2020-05-17 8:17 ` Sakkinen, Jarkko
2020-05-07 23:11 ` [PATCH v9 2/8] oid_registry: Add TCG defined OIDS for TPM keys James Bottomley
2020-05-07 23:11 ` [PATCH v9 3/8] security: keys: trusted: fix TPM2 authorizations James Bottomley
2020-05-14 1:11 ` Jarkko Sakkinen
2020-05-14 1:12 ` Jarkko Sakkinen
2020-05-14 1:41 ` James Bottomley [this message]
2020-05-14 11:19 ` Jarkko Sakkinen
2020-05-07 23:11 ` [PATCH v9 4/8] security: keys: trusted: use ASN.1 TPM2 key format for the blobs James Bottomley
2020-05-17 8:18 ` Sakkinen, Jarkko
2020-05-07 23:11 ` [PATCH v9 5/8] security: keys: trusted: Make sealed key properly interoperable James Bottomley
2020-05-07 23:11 ` [PATCH v9 6/8] security: keys: trusted: add PCR policy to TPM2 keys James Bottomley
2020-05-07 23:11 ` [PATCH v9 7/8] security: keys: trusted: add ability to specify arbitrary policy James Bottomley
2020-05-07 23:11 ` [PATCH v9 8/8] security: keys: trusted: implement counter/timer policy James Bottomley
2020-05-14 14:31 ` [PATCH v9 0/8] TPM 2.0 trusted keys with attached policy Jarkko Sakkinen
2020-05-15 2:22 ` Jarkko Sakkinen
2020-05-15 3:44 ` James Bottomley
2020-05-15 8:47 ` Jarkko Sakkinen
2020-05-15 9:30 ` Jerry Snitselaar
2020-05-15 18:48 ` James Bottomley
2020-05-16 12:24 ` Jarkko Sakkinen
2020-05-16 9:59 ` Jarkko Sakkinen
2020-05-15 19:17 ` Jerry Snitselaar
2020-05-15 19:34 ` James Bottomley
2020-05-15 19:50 ` Mimi Zohar
2020-05-15 20:10 ` James Bottomley
2020-05-15 21:03 ` Kayaalp, Mehmet
2020-05-15 22:19 ` James Bottomley
2020-05-15 23:23 ` James Bottomley
2020-05-16 21:44 ` Jarkko Sakkinen
2020-05-16 13:01 ` Sakkinen, Jarkko
2020-05-16 12:33 ` Jarkko Sakkinen
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