From: Matthew Garrett <mjg59@srcf.ucam.org>
To: "Stephan Müller" <smueller@chronox.de>
Cc: Andy Lutomirski <luto@kernel.org>, Ted Ts'o <tytso@mit.edu>,
LKML <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Kees Cook <keescook@chromium.org>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
"Ahmed S. Darwish" <darwish.07@gmail.com>,
Lennart Poettering <mzxreary@0pointer.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"Alexander E. Patrakov" <patrakov@gmail.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Willy Tarreau <w@1wt.eu>,
Ext4 Developers List <linux-ext4@vger.kernel.org>,
linux-man <linux-man@vger.kernel.org>
Subject: Re: [PATCH v3 0/8] Rework random blocking
Date: Thu, 26 Dec 2019 10:03:34 +0000 [thread overview]
Message-ID: <20191226100334.bsh3b3dphs4j4cvx@srcf.ucam.org> (raw)
In-Reply-To: <9872655.prSdhymlXK@positron.chronox.de>
On Thu, Dec 26, 2019 at 10:29:00AM +0100, Stephan Müller wrote:
>
> What about offering a compile-time option to enable or disable such code?
> Note, with the existing random.c code base, there is no need to have a
> separate blocking_pool. The ChaCha20 DRNG could be used for that very same
> purpose, provided that in case these true random numbers are generated when
> the Chacha20 DRNG received an equal amount of "unused" entropy.
I think it's reasonable to offer such an option as long as it's made
clear that it'll break userland and should only be enabled under very
weird circumstances. We don't want to end up in a situation where
userland developers feel that they need to code to handle such
situations - the only people who care about this distinction should be
in control of their userland stack and able to cope with the
consequences.
> If an unprivileged caller requests true random data, at least 1024 bits of
> entropy is left in the pool. I.e. all entropy above that point is available
> for this request type. Note, even namespaces fall into this category
> considering that unprivileged users can create a user name space in which they
> can become root.
I also feel like describing any of this as "true random data" is
misleading. Most of our entropy sources are devices that could, given
sufficient information, be modelled accurately. We're not sampling
quantum events here.
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2019-12-26 10:21 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-23 8:20 [PATCH v3 0/8] Rework random blocking Andy Lutomirski
2019-12-23 8:20 ` [PATCH v3 1/8] random: Don't wake crng_init_wait when crng_init == 1 Andy Lutomirski
2020-01-07 20:42 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 2/8] random: Add a urandom_read_nowait() for random APIs that don't warn Andy Lutomirski
2020-01-07 20:43 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 3/8] random: Add GRND_INSECURE to return best-effort non-cryptographic bytes Andy Lutomirski
2020-01-07 20:44 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 4/8] random: Ignore GRND_RANDOM in getentropy(2) Andy Lutomirski
2020-01-07 20:44 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 5/8] random: Make /dev/random be almost like /dev/urandom Andy Lutomirski
2020-01-07 21:02 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 6/8] random: Remove the blocking pool Andy Lutomirski
2020-01-07 21:03 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 7/8] random: Delete code to pull data into pools Andy Lutomirski
2020-01-07 21:03 ` Theodore Y. Ts'o
2019-12-23 8:20 ` [PATCH v3 8/8] random: Remove kernel.random.read_wakeup_threshold Andy Lutomirski
2020-01-07 21:04 ` Theodore Y. Ts'o
2019-12-26 9:29 ` [PATCH v3 0/8] Rework random blocking Stephan Müller
2019-12-26 10:03 ` Matthew Garrett [this message]
2019-12-26 11:40 ` Stephan Mueller
2019-12-26 11:12 ` Andy Lutomirski
2019-12-26 12:03 ` Stephan Mueller
2019-12-26 12:46 ` Andy Lutomirski
2019-12-27 9:55 ` Stephan Mueller
2019-12-26 14:04 ` Theodore Y. Ts'o
2019-12-26 23:29 ` Andy Lutomirski
2019-12-27 10:29 ` Stephan Mueller
2019-12-27 13:04 ` Theodore Y. Ts'o
2019-12-27 21:22 ` Stephan Mueller
2019-12-27 22:08 ` Theodore Y. Ts'o
2019-12-28 2:06 ` Andy Lutomirski
2019-12-29 14:49 ` Theodore Y. Ts'o
2019-12-29 15:08 ` Andy Lutomirski
2019-12-28 7:01 ` Willy Tarreau
2020-01-09 22:02 ` Kurt Roeckx
2020-01-09 22:02 ` Kurt Roeckx
2020-01-09 22:40 ` Theodore Y. Ts'o
2020-01-09 22:40 ` Theodore Y. Ts'o
2020-01-09 23:02 ` Kurt Roeckx
2020-01-09 23:02 ` Kurt Roeckx
2020-01-10 7:53 ` Stephan Mueller
2020-01-10 7:53 ` Stephan Mueller
2020-01-10 0:30 ` Andy Lutomirski
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