From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Janne Karhunen <janne.karhunen@gmail.com>
Cc: linux-integrity@vger.kernel.org,
David Safford <david.safford@ge.com>,
Pascal Van Leeuwen <pvanleeuwen@verimatrix.com>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
open list <linux-kernel@vger.kernel.org>,
Mimi Zohar <zohar@linux.ibm.com>
Subject: Re: [PATCH] tpm: Salt tpm_get_random() result with get_random_bytes()
Date: Wed, 16 Oct 2019 13:41:10 +0300 [thread overview]
Message-ID: <20191016104110.GB10184@linux.intel.com> (raw)
In-Reply-To: <CAE=NcraH_6nDe4Ax9axsbsrMf+EggCQFibY3dpNNgGm7NYTtJQ@mail.gmail.com>
On Wed, Oct 16, 2019 at 10:02:01AM +0300, Janne Karhunen wrote:
> On Tue, Oct 15, 2019 at 3:50 PM Jarkko Sakkinen
> <jarkko.sakkinen@linux.intel.com> wrote:
> >
> > Salt the result that comes from the TPM RNG with random bytes from the
> > kernel RNG. This will allow to use tpm_get_random() as a substitute for
> > get_random_bytes(). TPM could have a bug (making results predicatable),
> > backdoor or even an inteposer in the bus. Salting gives protections
> > against these concerns.
>
> The current issue in the randomness from my point of view is that
> encrypted filesystems, ima etc in common deployments require high
> quality entropy just few seconds after the system has powered on for
> the first time. It is likely that people want to keep their keys
> device specific, so the keys need to be generated on the first boot
> before any of the filesystems mount.
This patch does not have the described issue.
Which call sites are you talking about?
/Jarkko
next prev parent reply other threads:[~2019-10-16 10:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-15 12:47 [PATCH] tpm: Salt tpm_get_random() result with get_random_bytes() Jarkko Sakkinen
2019-10-15 17:04 ` Jason Gunthorpe
2019-10-16 10:38 ` Jarkko Sakkinen
2019-10-16 10:43 ` Jarkko Sakkinen
2019-10-16 16:09 ` Jason Gunthorpe
2019-10-17 16:21 ` Jarkko Sakkinen
2019-10-16 7:02 ` Janne Karhunen
2019-10-16 10:41 ` Jarkko Sakkinen [this message]
2019-10-16 11:16 ` Janne Karhunen
2019-10-16 16:23 ` Jarkko Sakkinen
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