From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Mimi Zohar <zohar@linux.ibm.com>
Cc: David Safford <david.safford@ge.com>,
linux-integrity@vger.kernel.org, stable@vger.kernel.org,
David Howells <dhowells@redhat.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>,
"open list:ASYMMETRIC KEYS" <keyrings@vger.kernel.org>,
"open list:CRYPTO API" <linux-crypto@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] KEYS: asym_tpm: Switch to get_random_bytes()
Date: Fri, 4 Oct 2019 00:57:43 +0300 [thread overview]
Message-ID: <20191003215743.GB30511@linux.intel.com> (raw)
In-Reply-To: <20191003215125.GA30511@linux.intel.com>
On Fri, Oct 04, 2019 at 12:51:25AM +0300, Jarkko Sakkinen wrote:
> On Thu, Oct 03, 2019 at 02:53:47PM -0400, Mimi Zohar wrote:
> > [Cc'ing David Safford]
> >
> > On Thu, 2019-10-03 at 20:58 +0300, Jarkko Sakkinen wrote:
> > > On Thu, Oct 03, 2019 at 09:02:32AM -0400, Mimi Zohar wrote:
> > > > On Thu, 2019-10-03 at 14:41 +0300, Jarkko Sakkinen wrote:
> > > > > On Wed, Oct 02, 2019 at 10:00:19AM -0400, Mimi Zohar wrote:
> > > > > > On Thu, 2019-09-26 at 20:16 +0300, Jarkko Sakkinen wrote:
> > > > > > > Only the kernel random pool should be used for generating random numbers.
> > > > > > > TPM contributes to that pool among the other sources of entropy. In here it
> > > > > > > is not, agreed, absolutely critical because TPM is what is trusted anyway
> > > > > > > but in order to remove tpm_get_random() we need to first remove all the
> > > > > > > call sites.
> > > > > >
> > > > > > At what point during boot is the kernel random pool available? Does
> > > > > > this imply that you're planning on changing trusted keys as well?
> > > > >
> > > > > Well trusted keys *must* be changed to use it. It is not a choice
> > > > > because using a proprietary random number generator instead of defacto
> > > > > one in the kernel can be categorized as a *regression*.
> > > >
> > > > I really don't see how using the TPM random number for TPM trusted
> > > > keys would be considered a regression. That by definition is a
> > > > trusted key. If anything, changing what is currently being done would
> > > > be the regression.
> > >
> > > It is really not a TPM trusted key. It trusted key that gets sealed with
> > > the TPM. The key itself is used in clear by kernel. The random number
> > > generator exists in the kernel to for a reason.
> > >
> > > It is without doubt a regression.
> >
> > You're misusing the term "regression" here. A regression is something
> > that previously worked and has stopped working. In this case, trusted
> > keys has always been based on the TPM random number generator. Before
> > changing this, there needs to be some guarantees that the kernel
> > random number generator has a pool of random numbers early, on all
> > systems including embedded devices, not just servers.
>
> I'm not using the term regression incorrectly here. Wrong function
> was used to generate random numbers for the payload here. It is an
> obvious bug.
At the time when trusted keys was introduced I'd say that it was a wrong
design decision and badly implemented code. But you are right in that as
far that code is considered it would unfair to speak of a regression.
asym-tpm.c on the other hand this is fresh new code. There has been
*countless* of discussions over the years that random numbers should
come from multiple sources of entropy. There is no other categorization
than a bug for the tpm_get_random() there.
/Jarkko
next prev parent reply other threads:[~2019-10-03 21:57 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 17:16 [PATCH] KEYS: asym_tpm: Switch to get_random_bytes() Jarkko Sakkinen
2019-09-28 18:05 ` Jerry Snitselaar
2019-10-01 20:54 ` Jarkko Sakkinen
2019-10-02 14:00 ` Mimi Zohar
2019-10-03 11:41 ` Jarkko Sakkinen
2019-10-03 11:43 ` Jarkko Sakkinen
2019-10-03 13:02 ` Mimi Zohar
2019-10-03 17:58 ` Jarkko Sakkinen
2019-10-03 18:53 ` Mimi Zohar
2019-10-03 21:51 ` Jarkko Sakkinen
2019-10-03 21:57 ` Jarkko Sakkinen [this message]
2019-10-03 22:08 ` Mimi Zohar
2019-10-03 23:59 ` James Bottomley
2019-10-04 18:22 ` Jarkko Sakkinen
2019-10-04 18:24 ` James Bottomley
2019-10-04 18:33 ` Jerry Snitselaar
2019-10-04 18:42 ` James Bottomley
2019-10-04 20:07 ` Jerry Snitselaar
2019-10-04 20:11 ` Jerry Snitselaar
2019-10-04 22:11 ` James Bottomley
2019-10-06 0:38 ` Mimi Zohar
2019-10-06 23:52 ` Jarkko Sakkinen
2019-10-07 18:08 ` Mimi Zohar
2019-10-04 18:20 ` Jarkko Sakkinen
2019-10-03 22:10 ` Jarkko Sakkinen
2019-10-04 13:26 ` Safford, David (GE Global Research, US)
2019-10-04 18:27 ` Jarkko Sakkinen
2019-10-04 18:30 ` Jarkko Sakkinen
2019-10-04 19:56 ` Safford, David (GE Global Research, US)
2019-10-07 0:05 ` Jarkko Sakkinen
2019-10-07 22:13 ` Ken Goldman
2019-10-08 23:49 ` Jarkko Sakkinen
2019-10-08 23:53 ` Jarkko Sakkinen
2019-10-09 7:10 ` Pascal Van Leeuwen
2019-10-09 7:33 ` Jarkko Sakkinen
2019-10-09 7:41 ` Jarkko Sakkinen
2019-10-09 8:09 ` Pascal Van Leeuwen
2019-10-14 19:11 ` Jarkko Sakkinen
2019-10-09 8:02 ` Pascal Van Leeuwen
2019-10-09 12:11 ` Safford, David (GE Global Research, US)
2019-10-14 19:00 ` Jarkko Sakkinen
2019-10-14 19:29 ` Jarkko Sakkinen
2019-10-14 19:29 ` James Bottomley
2019-10-16 11:00 ` Jarkko Sakkinen
2019-10-16 12:34 ` James Bottomley
2019-10-16 16:25 ` Jarkko Sakkinen
2019-10-16 19:10 ` James Bottomley
2019-10-17 12:52 ` Sumit Garg
2019-10-17 12:58 ` James Bottomley
2019-10-17 18:04 ` Jarkko Sakkinen
2019-10-21 11:39 ` Jarkko Sakkinen
2019-10-29 8:42 ` Jarkko Sakkinen
2019-10-29 14:58 ` James Bottomley
2019-10-31 21:03 ` Jarkko Sakkinen
2019-10-18 7:32 ` Janne Karhunen
2019-10-03 18:02 ` Jarkko Sakkinen
2019-10-03 18:15 ` Jarkko Sakkinen
2019-10-07 10:33 ` Janne Karhunen
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