From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: "Safford, David (GE Global Research, US)" <david.safford@ge.com>,
Ken Goldman <kgold@linux.ibm.com>,
Mimi Zohar <zohar@linux.ibm.com>,
"linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"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: Tue, 29 Oct 2019 07:58:16 -0700 [thread overview]
Message-ID: <1572361096.4812.3.camel@HansenPartnership.com> (raw)
In-Reply-To: <20191029084258.GA5649@linux.intel.com>
On Tue, 2019-10-29 at 10:42 +0200, Jarkko Sakkinen wrote:
> On Mon, Oct 21, 2019 at 02:39:39PM +0300, Jarkko Sakkinen wrote:
> > On Thu, Oct 17, 2019 at 09:04:40PM +0300, Jarkko Sakkinen wrote:
> > > On Wed, Oct 16, 2019 at 03:10:29PM -0400, James Bottomley wrote:
> > > > On Wed, 2019-10-16 at 19:25 +0300, Jarkko Sakkinen wrote:
> > > > > On Wed, Oct 16, 2019 at 08:34:12AM -0400, James Bottomley
> > > > > wrote:
> > > > > > reversible ciphers are generally frowned upon in random
> > > > > > number
> > > > > > generation, that's why the krng uses chacha20. In general
> > > > > > I think
> > > > > > we shouldn't try to code our own mixing and instead should
> > > > > > get the
> > > > > > krng to do it for us using whatever the algorithm du jour
> > > > > > that the
> > > > > > crypto guys have blessed is. That's why I proposed adding
> > > > > > the TPM
> > > > > > output to the krng as entropy input and then taking the
> > > > > > output of
> > > > > > the krng.
> > > > >
> > > > > It is already registered as hwrng. What else?
> > > >
> > > > It only contributes entropy once at start of OS.
> > >
> > > Ok.
> > >
> > > > > Was the issue that it is only used as seed when the rng is
> > > > > init'd
> > > > > first? I haven't at this point gone to the internals of krng.
> > > >
> > > > Basically it was similar to your xor patch except I got the
> > > > kernel rng
> > > > to do the mixing, so it would use the chacha20 cipher at the
> > > > moment
> > > > until they decide that's unsafe and change it to something
> > > > else:
> > > >
> > > > https://lore.kernel.org/linux-crypto/1570227068.17537.4.camel@H
> > > > ansenPartnership.com/
> > > >
> > > > It uses add_hwgenerator_randomness() to do the mixing. It also
> > > > has an
> > > > unmixed source so that read of the TPM hwrng device works as
> > > > expected.
> > >
> > > Thinking that could this potentially racy? I.e. between the calls
> > > something else could eat the entropy added?
> >
> > Also, what is wrong just taking one value from krng and mixing
> > it with a value from TPM RNG where needed? That would be non-racy
> > too.
>
> I guess we can move forward with this?
Sure I suppose; can we can figure out how to get the mixing function du
jour exposed?
James
next prev parent reply other threads:[~2019-10-29 14:58 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1572361096.4812.3.camel@HansenPartnership.com \
--to=james.bottomley@hansenpartnership.com \
--cc=david.safford@ge.com \
--cc=jarkko.sakkinen@linux.intel.com \
--cc=keyrings@vger.kernel.org \
--cc=kgold@linux.ibm.com \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=stable@vger.kernel.org \
--cc=zohar@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).