From: Stefan Berger <stefanb@linux.vnet.ibm.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] virtio-rng and fd passing
Date: Fri, 01 Mar 2013 15:13:10 -0500 [thread overview]
Message-ID: <51310BD6.20708@linux.vnet.ibm.com> (raw)
In-Reply-To: <51310365.8040102@zytor.com>
On 03/01/2013 02:37 PM, H. Peter Anvin wrote:
> On 02/28/2013 04:36 PM, Eric Blake wrote:
>> Stefan Berger and I discovered on IRC that virtio-rng is unable to
>> support fd passing. We attempted:
>>
>> qemu-system-x86_64 ... -add-fd
>> set=4,fd=34,opaque=RDONLY:/dev/urandom
> ^^^^^^^^^^^^
>> -object rng-random,id=rng0,filename=/dev/fdset/4 -device
>> virtio-rng-pci,rng=rng0,bus=pci.0,addr=0x6
>>
> Unrelated, but you really, really, really don't want to pass
> /dev/urandom there, use /dev/random.
From what I am reading about /dev/random is that it will start blocking
once not enough entropy is available anymore. Sounds like this could be
abused if multiple VMs were using this device and one drains the
entropy.. An alternative may be to pick go through a crypto library that
seeds itself with entropy and implements random number generators
following NIST 800-90 for example. Freebl would offer at least one such
implementation:
http://dxr.mozilla.org/mozilla-central/security/nss/lib/freebl/drbg.c.html
- search for 'NIST' there
Stefan
next prev parent reply other threads:[~2013-03-01 20:13 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <512FF819.7050505@redhat.com>
2013-03-01 9:51 ` [Qemu-devel] virtio-rng and fd passing Paolo Bonzini
2013-03-04 4:29 ` Amit Shah
2013-03-06 6:20 ` Amit Shah
2013-03-01 19:37 ` H. Peter Anvin
2013-03-01 20:13 ` Stefan Berger [this message]
2013-03-01 20:15 ` H. Peter Anvin
2013-03-01 20:41 ` Paolo Bonzini
2013-03-01 20:04 ` Anthony Liguori
2013-03-01 20:34 ` Stefan Berger
2013-03-01 21:08 ` Anthony Liguori
2013-03-01 21:13 ` Eric Blake
2013-03-01 23:05 ` Anthony Liguori
2013-03-01 23:14 ` Eric Blake
2013-03-01 23:59 ` Anthony Liguori
2013-03-02 0:29 ` Eric Blake
2013-03-02 3:13 ` Anthony Liguori
2013-03-02 12:23 ` Paolo Bonzini
2013-03-03 21:05 ` Anthony Liguori
2013-03-04 21:57 ` Eric Blake
2013-03-04 22:24 ` Anthony Liguori
2013-03-04 22:35 ` Eric Blake
2013-03-05 4:44 ` H. Peter Anvin
2013-03-04 21:54 ` Eric Blake
2013-03-02 0:34 ` Stefan Berger
2013-03-02 3:17 ` Anthony Liguori
2013-03-02 3:34 ` Stefan Berger
2013-03-03 21:06 ` Anthony Liguori
2013-03-04 15:27 ` Corey Bryant
2013-03-04 10:29 ` Daniel P. Berrange
2013-03-04 15:55 ` Corey Bryant
2013-03-01 22:59 ` Peter Krempa
2013-03-01 23:14 ` Anthony Liguori
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