From: Lennart Poettering <mzxreary@0pointer.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Alexander E. Patrakov" <patrakov@gmail.com>,
"Ahmed S. Darwish" <darwish.07@gmail.com>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
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>,
linux-ext4@vger.kernel.org, lkml <linux-kernel@vger.kernel.org>
Subject: Re: Linux 5.3-rc8
Date: Sun, 15 Sep 2019 08:56:55 +0200 [thread overview]
Message-ID: <20190915065655.GB29681@gardel-login> (raw)
In-Reply-To: <CAHk-=wiB0e_uGpidYHf+dV4eeT+XmG-+rQBx=JJ110R48QFFWw@mail.gmail.com>
On Sa, 14.09.19 09:52, Linus Torvalds (torvalds@linux-foundation.org) wrote:
> On Sat, Sep 14, 2019 at 9:35 AM Alexander E. Patrakov
> <patrakov@gmail.com> wrote:
> >
> > Let me repeat: not -EINVAL, please. Please find some other error code,
> > so that the application could sensibly distinguish between this case
> > (low quality entropy is in the buffer) and the "kernel is too dumb" case
> > (and no entropy is in the buffer).
>
> I'm not convinced we want applications to see that difference.
>
> The fact is, every time an application thinks it cares, it has caused
> problems. I can just see systemd saying "ok, the kernel didn't block,
> so I'll just do
>
> while (getrandom(x) == -ENOENTROPY)
> sleep(1);
>
> instead. Which is still completely buggy garbage.
>
> The fact is, we can't guarantee entropy in general. It's probably
> there is practice, particularly with user space saving randomness from
> last boot etc, but that kind of data may be real entropy, but the
> kernel cannot *guarantee* that it is.
I am not expecting the kernel to guarantee entropy. I just expecting
the kernel to not give me garbage knowingly. It's OK if it gives me
garbage unknowingly, but I have a problem if it gives me trash all the
time.
There's benefit in being able to wait until the pool is initialized
before we update the random seed stored on disk with a new one, and
there's benefit in being able to wait until the pool is initialized
before we let cryptsetup read a fresh, one-time key for dm-crypt from
/dev/urandom. I fully understand that any such reporting for
initialization is "best-effort", i.e. to the point where we don't know
anything to the contrary, but at least give userspace that.
Lennart
--
Lennart Poettering, Berlin
next prev parent reply other threads:[~2019-09-15 6:57 UTC|newest]
Thread overview: 211+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAHk-=whBQ+6c-h+htiv6pp8ndtv97+45AH9WvdZougDRM6M4VQ@mail.gmail.com>
2019-09-10 4:21 ` Linux 5.3-rc8 Ahmed S. Darwish
2019-09-10 11:33 ` Linus Torvalds
2019-09-10 12:21 ` Linus Torvalds
2019-09-10 17:33 ` Ahmed S. Darwish
2019-09-10 17:47 ` Reindl Harald
2019-09-10 18:21 ` Linus Torvalds
2019-09-11 16:07 ` Theodore Y. Ts'o
2019-09-11 16:45 ` Linus Torvalds
2019-09-11 17:00 ` Linus Torvalds
2019-09-11 17:36 ` Theodore Y. Ts'o
2019-09-12 3:44 ` Ahmed S. Darwish
2019-09-12 8:25 ` Theodore Y. Ts'o
2019-09-12 11:34 ` Linus Torvalds
2019-09-12 11:58 ` Willy Tarreau
2019-09-14 12:25 ` [PATCH RFC] random: getrandom(2): don't block on non-initialized entropy pool Ahmed S. Darwish
2019-09-14 14:08 ` Alexander E. Patrakov
2019-09-15 5:22 ` [PATCH RFC v2] random: optionally block in getrandom(2) when the CRNG is uninitialized Theodore Y. Ts'o
2019-09-15 8:17 ` [PATCH RFC v3] random: getrandom(2): optionally block when " Ahmed S. Darwish
2019-09-15 8:59 ` Lennart Poettering
2019-09-15 9:30 ` Willy Tarreau
2019-09-15 10:02 ` Ahmed S. Darwish
2019-09-15 10:40 ` Willy Tarreau
2019-09-15 10:55 ` Ahmed S. Darwish
2019-09-15 11:17 ` Willy Tarreau
2019-09-15 17:32 ` [PATCH RFC v2] random: optionally block in getrandom(2) when the " Linus Torvalds
2019-09-15 18:32 ` Willy Tarreau
2019-09-15 18:36 ` Willy Tarreau
2019-09-15 19:08 ` Linus Torvalds
2019-09-15 19:18 ` Willy Tarreau
2019-09-15 19:31 ` Linus Torvalds
2019-09-15 19:54 ` Willy Tarreau
2019-09-15 18:59 ` Linus Torvalds
2019-09-15 19:12 ` Willy Tarreau
2019-09-16 2:45 ` Ahmed S. Darwish
2019-09-16 18:08 ` Lennart Poettering
2019-09-16 19:16 ` Willy Tarreau
2019-09-18 21:15 ` [PATCH RFC v4 0/1] random: WARN on large getrandom() waits and introduce getrandom2() Ahmed S. Darwish
2019-09-18 21:17 ` [PATCH RFC v4 1/1] " Ahmed S. Darwish
2019-09-18 23:57 ` Linus Torvalds
2019-09-19 14:34 ` Theodore Y. Ts'o
2019-09-19 15:20 ` Linus Torvalds
2019-09-19 15:50 ` Linus Torvalds
2019-09-20 13:13 ` Theodore Y. Ts'o
2019-09-19 20:04 ` Linus Torvalds
2019-09-19 20:45 ` Alexander E. Patrakov
2019-09-19 21:47 ` Linus Torvalds
2019-09-19 22:23 ` Alexander E. Patrakov
2019-09-19 23:44 ` Alexander E. Patrakov
2019-09-20 13:16 ` Theodore Y. Ts'o
2019-09-23 11:55 ` David Laight
2019-09-20 13:08 ` Theodore Y. Ts'o
2019-09-20 13:46 ` Ahmed S. Darwish
2019-09-20 14:33 ` Andy Lutomirski
2019-09-20 16:29 ` Linus Torvalds
2019-09-20 17:52 ` Andy Lutomirski
2019-09-20 18:09 ` Linus Torvalds
2019-09-20 18:16 ` Willy Tarreau
2019-09-20 19:12 ` Andy Lutomirski
2019-09-20 19:51 ` Linus Torvalds
2019-09-20 20:11 ` Alexander E. Patrakov
2019-09-20 20:17 ` Matthew Garrett
2019-09-20 20:51 ` Andy Lutomirski
2019-09-20 22:44 ` Linus Torvalds
2019-09-20 23:30 ` Andy Lutomirski
2019-09-21 3:05 ` Willy Tarreau
2019-09-21 6:07 ` Florian Weimer
2019-09-23 18:33 ` Andy Lutomirski
2019-09-26 21:11 ` Ahmed S. Darwish
2019-09-20 18:12 ` Willy Tarreau
2019-09-20 19:22 ` Andy Lutomirski
2019-09-20 19:37 ` Willy Tarreau
2019-09-20 19:52 ` Andy Lutomirski
2019-09-20 20:02 ` Linus Torvalds
2019-09-20 18:15 ` Alexander E. Patrakov
2019-09-20 18:29 ` Andy Lutomirski
2019-09-20 17:26 ` Willy Tarreau
2019-09-20 17:56 ` Ahmed S. Darwish
2019-09-26 20:42 ` [PATCH v5 0/1] random: getrandom(2): warn on large CRNG waits, introduce new flags Ahmed S. Darwish
2019-09-26 20:44 ` [PATCH v5 1/1] " Ahmed S. Darwish
2019-09-26 21:39 ` Andy Lutomirski
2019-09-28 9:30 ` Ahmed S. Darwish
2019-09-14 15:02 ` Linux 5.3-rc8 Ahmed S. Darwish
2019-09-14 16:30 ` Linus Torvalds
2019-09-14 16:35 ` Alexander E. Patrakov
2019-09-14 16:52 ` Linus Torvalds
2019-09-14 17:09 ` Alexander E. Patrakov
2019-09-14 19:19 ` Linus Torvalds
2019-09-15 6:56 ` Lennart Poettering [this message]
2019-09-15 7:01 ` Willy Tarreau
2019-09-15 7:05 ` Lennart Poettering
2019-09-15 7:07 ` Willy Tarreau
2019-09-15 8:34 ` Lennart Poettering
2019-09-15 17:02 ` Linus Torvalds
2019-09-16 3:23 ` Theodore Y. Ts'o
2019-09-16 3:40 ` Linus Torvalds
2019-09-16 3:56 ` Linus Torvalds
2019-09-16 17:00 ` Theodore Y. Ts'o
2019-09-16 17:07 ` Linus Torvalds
2019-09-14 21:11 ` Ahmed S. Darwish
2019-09-14 22:05 ` Martin Steigerwald
2019-09-14 22:24 ` Theodore Y. Ts'o
2019-09-14 22:32 ` Linus Torvalds
2019-09-15 1:00 ` Theodore Y. Ts'o
2019-09-15 1:10 ` Linus Torvalds
2019-09-15 2:05 ` Theodore Y. Ts'o
2019-09-15 2:11 ` Linus Torvalds
2019-09-15 6:33 ` Willy Tarreau
2019-09-15 6:53 ` Willy Tarreau
2019-09-15 6:51 ` Lennart Poettering
2019-09-15 7:27 ` Ahmed S. Darwish
2019-09-15 8:48 ` Lennart Poettering
2019-09-15 16:29 ` Linus Torvalds
2019-09-16 1:40 ` Ahmed S. Darwish
2019-09-16 1:48 ` Vito Caputo
2019-09-16 2:49 ` Theodore Y. Ts'o
2019-09-16 4:29 ` Willy Tarreau
2019-09-16 5:02 ` Linus Torvalds
2019-09-16 6:12 ` Willy Tarreau
2019-09-16 16:17 ` Linus Torvalds
2019-09-16 17:21 ` Theodore Y. Ts'o
2019-09-16 17:44 ` Linus Torvalds
2019-09-16 17:55 ` Serge Belyshev
2019-09-16 19:08 ` Willy Tarreau
2019-09-16 23:02 ` Matthew Garrett
2019-09-16 23:05 ` Linus Torvalds
2019-09-16 23:11 ` Matthew Garrett
2019-09-16 23:13 ` Alexander E. Patrakov
2019-09-16 23:15 ` Matthew Garrett
2019-09-16 23:18 ` Linus Torvalds
2019-09-16 23:29 ` Ahmed S. Darwish
2019-09-17 1:05 ` Linus Torvalds
2019-09-17 1:23 ` Matthew Garrett
2019-09-17 1:41 ` Linus Torvalds
2019-09-17 1:46 ` Matthew Garrett
2019-09-17 5:24 ` Willy Tarreau
2019-09-17 7:33 ` Martin Steigerwald
2019-09-17 8:35 ` Willy Tarreau
2019-09-17 8:44 ` Martin Steigerwald
2019-09-17 12:11 ` Theodore Y. Ts'o
2019-09-17 12:30 ` Ahmed S. Darwish
2019-09-17 12:46 ` Alexander E. Patrakov
2019-09-17 12:47 ` Willy Tarreau
2019-09-17 16:08 ` Lennart Poettering
2019-09-17 16:23 ` Linus Torvalds
2019-09-17 16:34 ` Reindl Harald
2019-09-17 17:42 ` Lennart Poettering
2019-09-17 18:01 ` Linus Torvalds
2019-09-17 20:28 ` Martin Steigerwald
2019-09-17 20:52 ` Ahmed S. Darwish
2019-09-17 21:38 ` Martin Steigerwald
2019-09-17 21:52 ` Matthew Garrett
2019-09-17 22:10 ` Martin Steigerwald
2019-09-18 13:53 ` Lennart Poettering
2019-09-19 7:28 ` Martin Steigerwald
2019-09-17 23:08 ` Linus Torvalds
2019-09-18 13:40 ` Lennart Poettering
2019-09-17 20:58 ` Linus Torvalds
2019-09-18 9:33 ` Rasmus Villemoes
2019-09-18 10:16 ` Willy Tarreau
2019-09-18 10:25 ` Alexander E. Patrakov
2019-09-18 10:42 ` Willy Tarreau
2019-09-18 19:31 ` Linus Torvalds
2019-09-18 19:56 ` Eric W. Biederman
2019-09-18 20:13 ` Linus Torvalds
2019-09-18 20:15 ` Alexander E. Patrakov
2019-09-18 20:26 ` Linus Torvalds
2019-09-18 22:12 ` Willy Tarreau
2019-09-27 13:57 ` Lennart Poettering
2019-09-27 15:58 ` Linus Torvalds
2019-09-29 9:05 ` Lennart Poettering
2019-09-17 13:11 ` Alexander E. Patrakov
2019-09-17 13:37 ` Alexander E. Patrakov
2019-09-17 15:57 ` Lennart Poettering
2019-09-17 16:21 ` Willy Tarreau
2019-09-17 17:13 ` Lennart Poettering
2019-09-17 17:29 ` Willy Tarreau
2019-09-17 20:42 ` Martin Steigerwald
2019-09-18 13:38 ` Lennart Poettering
2019-09-18 13:59 ` Alexander E. Patrakov
2019-09-18 14:50 ` Alexander E. Patrakov
2019-09-17 20:36 ` Martin Steigerwald
2019-09-17 16:27 ` Linus Torvalds
2019-09-17 16:34 ` Matthew Garrett
2019-09-17 17:16 ` Willy Tarreau
2019-09-17 17:20 ` Matthew Garrett
2019-09-17 17:23 ` Matthew Garrett
2019-09-17 17:57 ` Willy Tarreau
2019-09-17 16:58 ` Alexander E. Patrakov
2019-09-17 17:30 ` Lennart Poettering
2019-09-17 17:32 ` Willy Tarreau
2019-09-17 17:41 ` Alexander E. Patrakov
2019-09-17 17:28 ` Lennart Poettering
2019-09-17 0:03 ` Matthew Garrett
2019-09-17 0:40 ` Matthew Garrett
2019-09-17 7:15 ` a sane approach to random numbers (was: Re: Linux 5.3-rc8) Martin Steigerwald
2019-09-16 18:00 ` Linux 5.3-rc8 Alexander E. Patrakov
2019-09-16 19:53 ` Ahmed S. Darwish
2019-09-17 15:32 ` Lennart Poettering
2019-09-16 3:31 ` Linus Torvalds
2019-09-23 20:49 ` chaos generating driver was " Pavel Machek
2019-09-14 9:25 ` Ahmed S. Darwish
2019-09-14 16:27 ` Theodore Y. Ts'o
2019-09-11 21:41 ` Ahmed S. Darwish
2019-09-11 22:37 ` Ahmed S. Darwish
2019-09-16 3:52 ` Herbert Xu
2019-09-16 4:21 ` Linus Torvalds
2019-09-16 4:53 ` Willy Tarreau
2019-09-10 11:56 ` Theodore Y. Ts'o
2019-09-16 10:33 ` Christoph Hellwig
2019-10-03 21:10 ` Jon Masters
2019-10-03 21:31 ` Jon Masters
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