[EXT] Re: [PATCH v5 3/5] KEYS: trusted: allow trust sources to use kernel RNG for key material

[Pankaj Gupta]

Reviewed-by: Pankaj Gupta <pankaj.gupta at nxp.com>

> -----Original Message-----
> From: Ahmad Fatoum <a.fatoum at pengutronix.de>
> Sent: Wednesday, February 23, 2022 9:53 PM
> To: James Bottomley <jejb at linux.ibm.com>; Jarkko Sakkinen
> <jarkko at kernel.org>; Mimi Zohar <zohar at linux.ibm.com>; David Howells
> <dhowells at redhat.com>
> Cc: kernel at pengutronix.de; Sumit Garg <sumit.garg at linaro.org>; David Gstir
> <david at sigma-star.at>; tharvey at gateworks.com; James Morris
> <jmorris at namei.org>; Serge E. Hallyn <serge at hallyn.com>; Horia Geanta
> <horia.geanta at nxp.com>; Aymen Sghaier <aymen.sghaier at nxp.com>; Herbert
> Xu <herbert at gondor.apana.org.au>; David S. Miller <davem at davemloft.net>;
> Eric Biggers <ebiggers at kernel.org>; Jan Luebbe <j.luebbe at pengutronix.de>;
> Richard Weinberger <richard at nod.at>; Franck Lenormand
> <franck.lenormand at nxp.com>; Matthias Schiffer <matthias.schiffer at ew.tq-
> group.com>; Pankaj Gupta <pankaj.gupta at nxp.com>; keyrings at vger.kernel.org;
> linux-crypto at vger.kernel.org; linux-integrity at vger.kernel.org; linux-
> kernel at vger.kernel.org; linux-security-module at vger.kernel.org
> Subject: [EXT] Re: [PATCH v5 3/5] KEYS: trusted: allow trust sources to use
> kernel RNG for key material
> 
> Caution: EXT Email
> 
> On 22.02.22 20:58, Ahmad Fatoum wrote:
> > The two existing trusted key sources don't make use of the kernel RNG,
> > but instead let the hardware that does the sealing/unsealing also
> > generate the random key material. While a previous change offers users
> > the choice to use the kernel RNG instead for both, new trust sources
> > may want to unconditionally use the kernel RNG for generating key
> > material, like it's done elsewhere in the kernel.
> >
> > This is especially prudent for hardware that has proven-in-production
> > HWRNG drivers implemented, as otherwise code would have to be
> > duplicated only to arrive at a possibly worse result.
> >
> > Make this possible by turning struct trusted_key_ops::get_random into
> > an optional member. If a driver leaves it NULL, kernel RNG will be
> > used instead.
> 
> The rebase on the change in scope of the previous commit made this one here
> quite small. I would squash it into the previous commit for v6, unless there are
> objections.
> 
> 
> >
> > Acked-by: Sumit Garg <sumit.garg at linaro.org>
> > Reviewed-by: David Gstir <david at sigma-star.at>
> > Tested-By: Tim Harvey <tharvey at gateworks.com>
> > Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> > ---
> > To: James Bottomley <jejb at linux.ibm.com>
> > To: Jarkko Sakkinen <jarkko at kernel.org>
> > To: Mimi Zohar <zohar at linux.ibm.com>
> > To: David Howells <dhowells at redhat.com>
> > Cc: James Morris <jmorris at namei.org>
> > Cc: "Serge E. Hallyn" <serge at hallyn.com>
> > Cc: "Horia Geantă" <horia.geanta at nxp.com>
> > Cc: Aymen Sghaier <aymen.sghaier at nxp.com>
> > Cc: Herbert Xu <herbert at gondor.apana.org.au>
> > Cc: "David S. Miller" <davem at davemloft.net>
> > Cc: Eric Biggers <ebiggers at kernel.org>
> > Cc: Jan Luebbe <j.luebbe at pengutronix.de>
> > Cc: David Gstir <david at sigma-star.at>
> > Cc: Richard Weinberger <richard at nod.at>
> > Cc: Franck LENORMAND <franck.lenormand at nxp.com>
> > Cc: Sumit Garg <sumit.garg at linaro.org>
> > Cc: Tim Harvey <tharvey at gateworks.com>
> > Cc: Matthias Schiffer <matthias.schiffer at ew.tq-group.com>
> > Cc: Pankaj Gupta <pankaj.gupta at nxp.com>
> > Cc: keyrings at vger.kernel.org
> > Cc: linux-crypto at vger.kernel.org
> > Cc: linux-integrity at vger.kernel.org
> > Cc: linux-kernel at vger.kernel.org
> > Cc: linux-security-module at vger.kernel.org
> > ---
> >  include/keys/trusted-type.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h
> > index d89fa2579ac0..4eb64548a74f 100644
> > --- a/include/keys/trusted-type.h
> > +++ b/include/keys/trusted-type.h
> > @@ -64,7 +64,7 @@ struct trusted_key_ops {
> >       /* Unseal a key. */
> >       int (*unseal)(struct trusted_key_payload *p, char *datablob);
> >
> > -     /* Get a randomized key. */
> > +     /* Optional: Get a randomized key. */
> >       int (*get_random)(unsigned char *key, size_t key_len);
> >
> >       /* Exit key interface. */
> 
> 
> --
> Pengutronix e.K.                           |                             |
> Steuerwalder Str. 21                       |
> https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.pen
> gutronix.de%2F&data=04%7C01%7Cpankaj.gupta%40nxp.com%7Cd6143a
> 1791a8494849f208d9f6e8cef8%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0
> %7C0%7C637812302026139014%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4
> wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&am
> p;sdata=2QRFygy%2BVafXrLIkF1BOHtDiwP%2Fz9kwU9ovtG1WJBTY%3D&r
> eserved=0  |
> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |