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From: "Stephan Müller" <smueller@chronox.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"Alexander E. Patrakov" <patrakov@gmail.com>,
	"Ahmed S. Darwish" <darwish.07@gmail.com>,
	"Theodore Y. Ts'o" <tytso@mit.edu>, Willy Tarreau <w@1wt.eu>,
	Matthew Garrett <mjg59@srcf.ucam.org>,
	Vito Caputo <vcaputo@pengaru.com>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	Jan Kara <jack@suse.cz>, Ray Strode <rstrode@redhat.com>,
	William Jon McCann <mccann@jhu.edu>,
	zhangjs <zachary@baishancloud.com>,
	Florian Weimer <fweimer@redhat.com>,
	Lennart Poettering <mzxreary@0pointer.de>,
	Nicolai Stange <nstange@suse.de>,
	"Peter, Matthias" <matthias.peter@bsi.bund.de>,
	Marcelo Henrique Cerri <marcelo.cerri@canonical.com>,
	Roman Drahtmueller <draht@schaltsekun.de>,
	Neil Horman <nhorman@redhat.com>
Subject: Re: [PATCH v24 00/12] /dev/random - a new approach with full SP800-90B compliance
Date: Wed, 13 Nov 2019 13:16:36 +0100	[thread overview]
Message-ID: <4999435.M7Dy0bkext@positron.chronox.de> (raw)
In-Reply-To: <CALCETrVHdauN2ptZLSYAUDm=S3OGkxq=iH4qGxCuH0XCMKjGkQ@mail.gmail.com>

Am Mittwoch, 13. November 2019, 05:48:30 CET schrieb Andy Lutomirski:

Hi Andy,

> 
> > - 6a26a3146e5fb90878dca9fde8caa1ca4233156a: My handler for /dev/urandom
> > and
> > getrandom(..., 0) are using one callback which issues a warning in both
> > use
> > cases (see lrng_sdrng_read). So I think this patch may not be applicable
> > as
> > the LRNG code implements warning about being unseeded.
> 
> Probably true.
> 
> What is the actual semantics of /dev/urandom with your series applied?
>  Is there any situation in which it will block?

The LRNG tries to provide a 100% identical user interface to the existing /
dev/random:

- /dev/urandom never blocks

- getrandom(..., 0) blocks until the LRNG has received 256 bits of entropy 
(i.e. the LRNG is fully seeded)

Yet, both may issue a warning if CONFIG_WARN_ALL_UNSEEDED_RANDOM is set.
> 
> > - 3e8e159da49b44ae0bb08e68fa2be760722fa033: I am happy to take that code
> > which would almost directly apply. The last hunk however would be:
> > 
> > if (!(flags & GRND_INSECURE) && unlikely(!lrng_state_operational())) {
> > 
> > ==> Shall I apply it to my code base? If yes, how shall the changes to
> > random.h be handled?
> 
> This might be a question for Ted.  Once the merge window opens, I'll
> resubmit it.

Ok, I will keep it out of the LRNG for now, but once your patch is merged, I 
would integrate it.
> 
> > - 920e97e7fc508e6f0da9c7dec94c8073fd63ab4d: I would pass on this patch due
> > to the following: it unconditionally starts removing the access to the
> > TRNG (the LRNG's logical equivalent to the blocking_pool). As patch 10/12
> > of the LRNG patch series provides the TRNG that is a compile time option,
> > your patch would logically and functionally be equivalent when
> > deselecting
> > CONFIG_LRNG_TRNG_SUPPORT in the LRNG without any further changes to the
> > LRNG code.
> 
> Given your previous email about the TRNG, I'm wondering what the API
> for the TRNG should be.  I am willing to grant that there are users
> who need a TRNG for various reasons, and that not all of them can use
> hwrng.  (And the current hwrng API is pretty bad.)  But I'm not
> convinced that /dev/random or getrandom(..., GRND_RANDOM) is a
> reasonable way to access it.  A blocking_pool-style TRNG is a very
> limited resource, and I think it could make sense to require some sort
> of actual permission to use it.  GRND_RANDOM has no access control at
> all, and everyone expects /dev/random to be world-readable.  The most
> widespread user of /dev/random that I know of is gnupg, and gnupg
> really should not be using it.
> 
> Would it make sense to have a /dev/true_random that is 0400 by default
> for users who actually need it?  Then /dev/random and GRND_RANDOM
> could work as they do with my patch, and maybe it does the right thing
> for everyone.

That is surely a reasonable way to do it. But I am not sure 0400 should be 
applied, but rather 0440. This should allow introducing a group in user space 
that processes who need the TRNG are not required to have root privilege, but 
rather need to be a member of some otherwise unprivileged group.
> 
> > - 693b9ffdf0fdc93456b5ad293ac05edf240a531b: This patch is applicable to
> > the
> > LRNG. In case CONFIG_LRNG_TRNG_SUPPORT is not set, the TRNG is not
> > present.
> > Yet, the /dev/random and getrandom(GRND_RANDOM) would behave blocked until
> > fully initialized. I have now added the general blocking until the LRNG is
> > fully initialized to the common /dev/random and getrandom(GRND_RANDOM)
> > interface function of lrng_trng_read_common. With that, the LRNG would be
> > fully equivalent to this patch if CONFIG_LRNG_TRNG_SUPPORT is not set.
> 
> Sounds reasonable.
> 
> > By making the TRNG compile-time selectable, I was hoping to serve all
> > users: I wanted to cover the conclusions of the discussion to remove the
> > blocking_pool. On the other hand, however, I want to support requirements
> > that need the blocking behavior.
> 
> I find it odd that /dev/random would be either a TRNG or not a TRNG
> depending on kernel configuration.  For the small fraction of users
> that actually want a TRNG, wouldn't it be better to have an interface
> that fails outright if the TRNG is not enabled?

Sure, I would have no concerns here.

> 
> --Andy


Ciao
Stephan



  reply	other threads:[~2019-11-13 12:18 UTC|newest]

Thread overview: 162+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-11 18:17 [PATCH v24 00/12] /dev/random - a new approach with full SP800-90B compliance Stephan Müller
2019-11-11 18:18 ` [PATCH v24 01/12] Linux Random Number Generator Stephan Müller
2019-11-11 23:54   ` Thomas Gleixner
2019-11-12  2:25     ` Stephan Müller
2019-11-12 10:16       ` Thomas Gleixner
2019-11-12 22:30   ` kbuild test robot
2019-11-12 23:15     ` Stephan Müller
2019-11-13  0:14   ` kbuild test robot
2019-11-13  0:25     ` Stephan Müller
2019-11-24  4:51   ` Sandy Harris
2019-11-24  9:02     ` Stephan Mueller
2019-11-11 18:19 ` [PATCH v24 02/12] LRNG - allocate one SDRNG instance per NUMA node Stephan Müller
2019-11-11 18:20 ` [PATCH v24 03/12] LRNG - /proc interface Stephan Müller
2019-11-11 18:20 ` [PATCH v24 04/12] LRNG - add switchable DRNG support Stephan Müller
2019-11-11 18:21 ` [PATCH v24 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller
2019-11-11 18:21 ` [PATCH v24 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller
2019-11-11 18:22 ` [PATCH v24 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller
2019-11-11 18:23 ` [PATCH v24 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller
2019-11-11 18:23 ` [PATCH v24 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller
2019-11-11 18:24 ` [PATCH v24 10/12] LRNG - add TRNG support Stephan Müller
2019-11-11 18:26 ` [PATCH v24 11/12] LRNG - add SP800-90B compliant health tests Stephan Müller
2019-11-12 19:58   ` Alexander E. Patrakov
2019-11-12 23:11     ` Stephan Müller
2019-11-13  0:36     ` Stephan Müller
2019-11-13  6:02       ` Alexander E. Patrakov
2019-11-14  1:46         ` Stephan Müller
2019-11-11 18:26 ` [PATCH v24 12/12] LRNG - add interface for gathering of raw entropy Stephan Müller
2019-11-12 20:55   ` kbuild test robot
2019-11-12 23:13     ` Stephan Müller
2019-11-12 13:23 ` [PATCH v24 00/12] /dev/random - a new approach with full SP800-90B compliance Florian Weimer
2019-11-12 22:43   ` Stephan Müller
2019-11-12 15:33 ` Andy Lutomirski
2019-11-12 23:03   ` Stephan Müller
2019-11-12 23:26     ` Stephan Müller
2019-11-13  4:24   ` Stephan Müller
2019-11-13  4:48     ` Andy Lutomirski
2019-11-13 12:16       ` Stephan Müller [this message]
2019-11-16  9:32 ` [PATCH v25 00/12] /dev/random - a new approach with full SP800-90B Stephan Müller
2019-11-16  9:33   ` [PATCH v25 01/12] Linux Random Number Generator Stephan Müller
2019-11-16 11:25     ` Thomas Gleixner
2019-11-17 10:30       ` Stephan Müller
2019-11-16 18:13     ` Nicolai Stange
2019-11-17 11:01       ` Stephan Müller
2019-11-16  9:33   ` [PATCH v25 02/12] LRNG - allocate one SDRNG instance per NUMA node Stephan Müller
2019-11-16  9:34   ` [PATCH v25 03/12] LRNG - /proc interface Stephan Müller
2019-11-16 16:39     ` Andy Lutomirski
2019-11-17 12:16       ` Stephan Müller
2019-11-19 10:06         ` Andy Lutomirski
2019-11-19 10:55           ` Stephan Mueller
2019-11-19 17:40             ` Andy Lutomirski
2019-11-16 23:36     ` Eric W. Biederman
2019-11-17 11:37       ` Stephan Müller
2019-11-16  9:34   ` [PATCH v25 04/12] LRNG - add switchable DRNG support Stephan Müller
2019-11-16  9:35   ` [PATCH v25 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller
2019-11-16  9:35   ` [PATCH v25 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller
2019-11-16  9:35   ` [PATCH v25 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller
2019-11-16  9:36   ` [PATCH v25 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller
2019-11-16  9:36   ` [PATCH v25 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller
2019-11-20 13:33     ` Neil Horman
2019-11-20 20:07       ` Stephan Müller
2019-11-21 14:19         ` Neil Horman
2019-11-21 14:33           ` Stephan Mueller
2019-11-16  9:37   ` [PATCH v25 10/12] LRNG - add TRNG support Stephan Müller
2019-11-16 16:09     ` Andy Lutomirski
2019-11-17 11:10       ` Stephan Müller
2019-11-19 10:07         ` Andy Lutomirski
2019-11-19 10:46           ` Stephan Mueller
2019-11-19 12:41           ` Greg Kroah-Hartman
2019-11-20  8:58             ` Stephan Müller
2019-11-20  9:55               ` Alexander E. Patrakov
2019-11-20 13:29               ` Greg Kroah-Hartman
2019-11-20 19:51                 ` Stephan Müller
2019-11-20 19:57                   ` Alexander E. Patrakov
2019-11-20 20:32                   ` Greg Kroah-Hartman
2019-11-21 13:06                     ` Stephan Müller
2019-11-16  9:37   ` [PATCH v25 11/12] LRNG - add SP800-90B compliant health tests Stephan Müller
2019-11-16  9:38   ` [PATCH v25 12/12] LRNG - add interface for gathering of raw entropy Stephan Müller
2019-11-16 16:51     ` Andy Lutomirski
2019-11-17 22:55       ` Stephan Müller
2019-11-19 10:04         ` Andy Lutomirski
2019-11-19 17:17     ` Randy Dunlap
2019-11-20  9:01       ` Stephan Müller
2019-11-21 12:18     ` Nicolai Stange
2019-11-21 15:18       ` Stephan Müller
2019-11-23 20:08   ` [PATCH v26 00/12] /dev/random - a new approach with full SP800-90B Stephan Müller
2019-11-23 20:10     ` [PATCH v26 01/12] Linux Random Number Generator Stephan Müller
2019-11-24 22:44       ` kbuild test robot
2019-11-25  6:29         ` Stephan Mueller
2019-11-23 20:10     ` [PATCH v26 02/12] LRNG - allocate one SDRNG instance per NUMA node Stephan Müller
2019-11-23 20:11     ` [PATCH v26 03/12] LRNG - sysctls and /proc interface Stephan Müller
2019-11-23 20:11     ` [PATCH v26 04/12] LRNG - add switchable DRNG support Stephan Müller
2019-11-23 20:31     ` [PATCH v26 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller
2019-11-23 20:32     ` [PATCH v26 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller
2019-11-23 20:32     ` [PATCH v26 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller
2019-11-23 20:33     ` [PATCH v26 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller
2019-11-23 20:34     ` [PATCH v26 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller
2019-11-23 20:34     ` [PATCH v26 10/12] LRNG - add TRNG support Stephan Müller
2019-11-23 20:34     ` [PATCH v26 11/12] LRNG - add SP800-90B compliant health tests Stephan Müller
2019-11-23 20:35     ` [PATCH v26 12/12] LRNG - add interface for gathering of raw entropy Stephan Müller
2020-01-09  8:29     ` [PATCH v27 00/12] /dev/random - a new approach with full SP800-90B Stephan Müller
2020-01-09  8:30       ` [PATCH v27 01/12] Linux Random Number Generator Stephan Müller
2020-01-16  6:09         ` kbuild test robot
2020-01-16  6:41           ` Stephan Mueller
2020-01-09  8:31       ` [PATCH v27 02/12] LRNG - allocate one DRNG instance per NUMA node Stephan Müller
2020-01-09  8:31       ` [PATCH v27 03/12] LRNG - sysctls and /proc interface Stephan Müller
2020-01-09  8:32       ` [PATCH v27 04/12] LRNG - add switchable DRNG support Stephan Müller
2020-01-11  7:09         ` kbuild test robot
2020-01-12 10:12           ` Stephan Müller
2020-01-09  8:32       ` [PATCH v27 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller
2020-01-09  8:32       ` [PATCH v27 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller
2020-01-09  8:33       ` [PATCH v27 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller
2020-01-09  8:33       ` [PATCH v27 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller
2020-01-09  8:34       ` [PATCH v27 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller
2020-01-10  0:24         ` Randy Dunlap
2020-01-10  7:45           ` Stephan Mueller
2020-01-09  8:34       ` [PATCH v27 10/12] LRNG - add SP800-90B compliant health tests Stephan Müller
2020-01-10  0:20         ` Randy Dunlap
2020-01-10  8:27           ` Stephan Mueller
2020-01-09  8:35       ` [PATCH v27 11/12] LRNG - add interface for gathering of raw entropy Stephan Müller
2020-01-09  8:35       ` [PATCH v27 12/12] LRNG - add power-on and runtime self-tests Stephan Müller
2020-01-10  0:22         ` Randy Dunlap
2020-01-10  7:48           ` Stephan Mueller
2020-01-13 10:39         ` Dan Carpenter
2020-01-13 10:46           ` Stephan Mueller
2020-01-15 10:31       ` [PATCH v28 00/12] /dev/random - a new approach with full SP800-90B Stephan Müller
2020-01-15 10:31         ` [PATCH v28 01/12] Linux Random Number Generator Stephan Müller
2020-01-16  0:11           ` Randy Dunlap
2020-01-16  7:22             ` Stephan Mueller
2020-01-15 10:32         ` [PATCH v28 02/12] LRNG - allocate one DRNG instance per NUMA node Stephan Müller
2020-01-15 10:32         ` [PATCH v28 03/12] LRNG - sysctls and /proc interface Stephan Müller
2020-01-15 10:32         ` [PATCH v28 04/12] LRNG - add switchable DRNG support Stephan Müller
2020-01-15 10:33         ` [PATCH v28 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller
2020-01-15 10:33         ` [PATCH v28 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller
2020-01-16  0:14           ` Randy Dunlap
2020-01-16  6:55             ` Stephan Mueller
2020-01-15 10:34         ` [PATCH v28 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller
2020-01-16  0:15           ` Randy Dunlap
2020-01-16  6:54             ` Stephan Mueller
2020-01-15 10:34         ` [PATCH v28 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller
2020-01-15 10:34         ` [PATCH v28 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller
2020-01-16  0:17           ` Randy Dunlap
2020-01-16  6:51             ` Stephan Mueller
2020-01-15 10:35         ` [PATCH v28 10/12] LRNG - add SP800-90B compliant health tests Stephan Müller
2020-01-15 10:35         ` [PATCH v28 11/12] LRNG - add interface for gathering of raw entropy Stephan Müller
2020-01-16  0:18           ` Randy Dunlap
2020-01-16  6:43             ` Stephan Mueller
2020-01-16  6:48               ` Randy Dunlap
2020-01-16  6:52                 ` Stephan Mueller
2020-01-15 10:36         ` [PATCH v28 12/12] LRNG - add power-on and runtime self-tests Stephan Müller
2020-01-19 21:12         ` [PATCH v29 00/12] /dev/random - a new approach with full SP800-90B Stephan Müller
2020-01-19 21:13           ` [PATCH v29 01/12] Linux Random Number Generator Stephan Müller
2020-01-19 21:13           ` [PATCH v29 02/12] LRNG - allocate one DRNG instance per NUMA node Stephan Müller
2020-01-19 21:14           ` [PATCH v29 03/12] LRNG - sysctls and /proc interface Stephan Müller
2020-01-19 21:14           ` [PATCH v29 04/12] LRNG - add switchable DRNG support Stephan Müller
2020-01-19 21:15           ` [PATCH v29 05/12] crypto: DRBG - externalize DRBG functions for LRNG Stephan Müller
2020-01-19 21:16           ` [PATCH v29 06/12] LRNG - add SP800-90A DRBG extension Stephan Müller
2020-01-19 21:16           ` [PATCH v29 07/12] LRNG - add kernel crypto API PRNG extension Stephan Müller
2020-01-19 21:17           ` [PATCH v29 08/12] crypto: provide access to a static Jitter RNG state Stephan Müller
2020-01-19 21:18           ` [PATCH v29 09/12] LRNG - add Jitter RNG fast noise source Stephan Müller
2020-01-19 21:18           ` [PATCH v29 10/12] LRNG - add SP800-90B compliant health tests Stephan Müller
2020-01-19 21:19           ` [PATCH v29 11/12] LRNG - add interface for gathering of raw entropy Stephan Müller
2020-01-19 21:20           ` [PATCH v29 12/12] LRNG - add power-on and runtime self-tests Stephan Müller

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