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From: Amit Shah <amit.shah@redhat.com>
To: Kees Cook <keescook@chromium.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Virtualization List <virtualization@lists.linux-foundation.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Jason Cooper <jason@lakedaemon.net>,
	"# 3.4.x" <stable@vger.kernel.org>
Subject: Re: [PATCH v2 2/2] virtio: rng: ensure reads happen after successful probe
Date: Mon, 7 Jul 2014 11:21:07 +0530	[thread overview]
Message-ID: <20140707055049.GA27024@grmbl.mre> (raw)
In-Reply-To: <CAGXu5jK1wL9DCnH0RcqhantcCvyJhwZfkw+_L7VQi8wfY2Nt_g@mail.gmail.com>

On (Sun) 06 Jul 2014 [21:38:36], Kees Cook wrote:
> On Fri, Jul 4, 2014 at 10:34 PM, Amit Shah <amit.shah@redhat.com> wrote:
> > The hwrng core asks for random data in the hwrng_register() call itself
> > from commit d9e7972619.  This doesn't play well with virtio -- the
> > DRIVER_OK bit is only set by virtio core on a successful probe, and
> > we're not yet out of our probe routine when this call is made.  This
> > causes the host to not acknowledge any requests we put in the virtqueue,
> > and the insmod or kernel boot process just waits for data to arrive from
> > the host, which never happens.
> 
> Doesn't this mean that virtio-rng won't ever contribute entropy to the system?

The initial randomness?  Yes.  But it'll start contributing entropy as
soon as it's used as the current source.

Is this a huge negative?

		Amit

  reply	other threads:[~2014-07-07  5:51 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1404538109.git.amit.shah@redhat.com>
2014-07-05  5:34 ` [PATCH v2 1/2] hwrng: fetch randomness only after device init Amit Shah
2014-07-07  4:41   ` Kees Cook
2014-07-07  5:53     ` Amit Shah
2014-07-07  6:04       ` Amit Shah
2014-07-07  6:39         ` Amit Shah
2014-07-09 11:53   ` Jason Cooper
2014-07-09 13:08     ` Amit Shah
2014-07-09 13:17       ` Jason Cooper
2014-07-09 13:25         ` Amit Shah
2014-07-09 16:07           ` [RFC PATCH] hwrng: sysfs entry rng_seed_kernel, was: "Re: [PATCH v2 1/2] hwrng: fetch randomness only after device init" Jason Cooper
2014-07-11 13:26             ` Amit Shah
2014-07-11 15:44               ` Jason Cooper
2014-07-14 21:50                 ` Kees Cook
2014-07-05  5:34 ` [PATCH v2 2/2] virtio: rng: ensure reads happen after successful probe Amit Shah
2014-07-07  4:38   ` Kees Cook
2014-07-07  5:51     ` Amit Shah [this message]
2014-07-07  6:09       ` Kees Cook
2014-07-07  6:34         ` Amit Shah
2014-07-09 12:08           ` Jason Cooper
2014-07-09 13:15             ` Amit Shah
2014-07-09 16:18   ` Jason Cooper
2014-07-10  8:45     ` Herbert Xu
2014-07-10  9:53       ` Amit Shah
2014-07-10  8:52     ` Amit Shah

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