Re: [Pce] PCE WG Last Call - draft-ietf-pce-pceps-04

[DIEGO LOPEZ GARCIA <[e-mail]>]

Hi Tom,

Thanks for the review. We will update the draft text addressing your comments and those we received form Cyril. Some notes inline below

On 4 Nov 2015, at 19:55 , t.p. <[e-mail]<mailto:[e-mail]>> wrote:

s.3 At first, I was unsure whether or not both parties sent a StartTLS.
"The StartTLS message is a PCEP message sent by a PCC to a PCE and by
  a PCE to a PCC " suggests both
"Once the TCP connection has been successfully established, the first
  message sent by the PCC to the PCE or  by the PCE to the PCC MUST be
a
  StartTLS message " suggests only one.
Section 3.3 makes it clearer that both send it.  This is fine but I am
unaware of any other protocol where this happens so I would suggest
/or/and/ in that second sentence and expanding the earlier sentence
OLD
  2.  Initiating the TLS Procedures by the StartTLS message.
NEW
  2.  Initiating the TLS Procedures by the StartTLS message from PCE to
PCC and from PCC to PCE.

DRL> You are right in the ambiguity and we will correct it as you suggest.

I focus on this because I was also looking to see which became TLS
Client.  TLS is asymmetric, designed to authenticate a (HTTP) server to
a client.  Netconf (and SNMP), which I know better, struggled with this
because the key for Netconf is to authenticate the client to the server,
which TLS does not do so well. Posts on the TLS list suggest that there
are very few implementations of TLS client authentication, rather
something else is done once the secure channel has been established.

DRL> I’d not say there are few implementations, but that client authentication is not commonly employed, especially in the web environment where other mechanisms are preferred, like using a TLS connection based on server authentication to retrieve password credentials from the user… As far as I can tell, TLS is only asymmetric in this requirement for authentication of both peers, as the crypto exchanges become essentially equal if client authentication is required.

So, do you care who is TLS client and who TLS server?  It will be
interesting to see a security review of this.

DRL> What we had in mind was that the natural approach taking into account the structure of PCEP was to have the PCC peer acting as client and the PCE acting as server. We’ll include a requirement in section 3.2 on this.  I do not see any security issue here, but we could certainly request the UTA WG to make a review. I’d say this completely falls under their area of interest.

In passing, RFC7465 prohibits RC4 with TLS so I would think it unlikely
that
"SHOULD support  TLS_RSA_WITH_RC4_128_SHA"  will be acceptable.

DRL> Good catch. It will ve deleted in the coming version.

Be goode,

--
"Esta vez no fallaremos, Doctor Infierno"

Dr Diego R. Lopez
Telefonica I+D
http://people.tid.es/diego.lopez/

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Mobile: [phone]
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