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From: Florian Weimer <fweimer@redhat.com>
To: Markus Armbruster <armbru@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>
Cc: libvir-list@redhat.com, mprivozn@redhat.com,
	nbd-general@lists.sf.net,
	"Richard W.M. Jones" <rjones@redhat.com>,
	qemu-devel@nongnu.org, Hani Benhabiles <kroosec@gmail.com>,
	nick@bytemark.co.uk, Wouter Verhelst <w@uter.be>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Max Reitz <mreitz@redhat.com>
Subject: Re: [Qemu-devel] spec, RFC: TLS support for NBD
Date: Mon, 20 Oct 2014 13:56:43 +0200	[thread overview]
Message-ID: <5444F87B.7010708@redhat.com> (raw)
In-Reply-To: <8738ajq7qo.fsf@blackfin.pond.sub.org>

On 10/20/2014 01:51 PM, Markus Armbruster wrote:
> Furthermore, STARTTLS is vulnerable to active attacks: if you can get
> between the peers, you can make them fall back to unencrypted silently.
> How do you plan to guard against that?

The usual way to deal with this is to use different syntax for 
TLS-enabled and non-TLS addresses (e.g., https:// and http://).  With a 
TLS address, the client must enforce that only TLS-enabled connections 
are possible.  STARTTLS isn't the problem here, it's just an accident of 
history that many STARTTLS client implementations do not require a TLS 
handshake before proceeding.

I cannot comment on whether the proposed STARTTLS command is at the 
correct stage of the NBD protocol.  If there is a protocol description 
for NBD, I can have a look.

-- 
Florian Weimer / Red Hat Product Security

  reply	other threads:[~2014-10-20 11:57 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-03 16:44 [Qemu-devel] NBD TLS support in QEMU Stefan Hajnoczi
2014-09-04 14:19 ` Benoît Canet
2014-09-04 14:34   ` [Qemu-devel] [libvirt] " Daniel P. Berrange
2014-09-04 15:04     ` Benoît Canet
2014-09-04 15:45       ` Stefan Hajnoczi
2014-09-04 15:54     ` John Snow
2014-09-04 22:07   ` [Qemu-devel] " Wouter Verhelst
2014-09-04 22:54     ` Benoît Canet
2014-09-05  8:42       ` Wouter Verhelst
2014-09-05 12:15       ` Stefan Hajnoczi
2014-09-04 22:02 ` Wouter Verhelst
2014-09-05  8:13   ` Daniel P. Berrange
2014-09-05  8:34     ` Wouter Verhelst
2014-09-05 12:21   ` Stefan Hajnoczi
2014-09-05  6:23 ` [Qemu-devel] [libvirt] " Michal Privoznik
2014-09-05  8:10   ` Daniel P. Berrange
2014-09-05  8:46 ` [Qemu-devel] " Hani Benhabiles
2014-09-05 12:31   ` Stefan Hajnoczi
2014-09-05 13:26   ` Wouter Verhelst
2014-10-01 20:23     ` Wouter Verhelst
2014-10-02 11:00       ` Paolo Bonzini
2014-10-02 13:50         ` Wouter Verhelst
2014-10-08 18:16           ` Wouter Verhelst
2014-10-09 12:42             ` Paolo Bonzini
2014-10-02 11:05       ` Daniel P. Berrange
2014-10-02 11:28         ` Paolo Bonzini
2014-10-17 22:03           ` [Qemu-devel] spec, RFC: TLS support for NBD Wouter Verhelst
2014-10-18  6:33             ` Richard W.M. Jones
2014-10-20  7:58               ` Daniel P. Berrange
2014-10-20  9:56                 ` Stefan Hajnoczi
2014-10-20 11:51                   ` Markus Armbruster
2014-10-20 11:56                     ` Florian Weimer [this message]
2014-10-20 12:48                       ` Richard W.M. Jones
2014-10-20 22:10                       ` Wouter Verhelst
2014-10-21  9:35                         ` Daniel P. Berrange
2014-10-21 18:02                           ` Wouter Verhelst
2014-10-20 12:08                     ` Daniel P. Berrange
2014-10-20 21:53                     ` [Qemu-devel] spec, RFC: TLS support for NBDµ Wouter Verhelst
2014-10-21  8:17                       ` Markus Armbruster
2014-10-21 18:30                         ` Wouter Verhelst
2014-10-25 10:43                           ` [Qemu-devel] [Nbd] " Wouter Verhelst
2014-10-30 10:40                             ` Stefan Hajnoczi
2014-10-31 18:15                               ` Wouter Verhelst
2014-11-03 14:30                                 ` Stefan Hajnoczi

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