Re: [Dots] Adoption call for draft-reddy-dots-home-network-04

["Konda, Tirumaleswar Reddy" <[e-mail]>]

> -----Original Message-----
> From: [e-mail]
> <[e-mail]>
> Sent: Wednesday, April 24, 2019 4:48 PM
> To: Konda, Tirumaleswar Reddy
> <[e-mail]>; Valery Smyslov
> <[e-mail]>; [e-mail]
> Cc: [e-mail]; [e-mail]
> Subject: RE: [Dots] Adoption call for draft-reddy-dots-home-network-04
> 
> This email originated from outside of the organization. Do not click links or
> open attachments unless you recognize the sender and know the content is
> safe.
> 
> Re-,
> 
> Please see inline.
> 
> Cheers,
> Med
> 
> > -----Message d'origine-----
> > De : Konda, Tirumaleswar Reddy
> > [mailto:[e-mail]]
> > Envoyé : mercredi 24 avril 2019 13:01
> > À : BOUCADAIR Mohamed TGI/OLN; Valery Smyslov; [e-mail] Cc :
> > [e-mail]; [e-mail] Objet : RE: [Dots] Adoption call
> > for draft-reddy-dots-home-network-04
> >
> > > -----Original Message-----
> > > From: [e-mail]
> > > <[e-mail]>
> > > Sent: Wednesday, April 24, 2019 12:18 PM
> > > To: Konda, Tirumaleswar Reddy
> > > <[e-mail]>; Valery Smyslov
> > > <[e-mail]>; [e-mail]
> > > Cc: [e-mail]; [e-mail]
> > > Subject: RE: [Dots] Adoption call for
> > > draft-reddy-dots-home-network-04
> > >
> > >
> > >
> > > Re-,
> > >
> > > Please see inline.
> > >
> > > Cheers,
> > > Med
> > >
> > > > -----Message d'origine-----
> > > > De : Konda, Tirumaleswar Reddy
> > > > [mailto:[e-mail]]
> > > > Envoyé : mercredi 24 avril 2019 08:13 À : BOUCADAIR Mohamed
> > > > TGI/OLN; Valery Smyslov; [e-mail] Cc :
> > > > [e-mail]; [e-mail] Objet : RE: [Dots] Adoption
> > > > call for draft-reddy-dots-home-network-04
> > > >
> > > > > -----Original Message-----
> > > > > From: Dots <[e-mail]> On Behalf Of
> > > > > [e-mail]
> > > > > Sent: Wednesday, April 24, 2019 11:26 AM
> > > > > To: Valery Smyslov <[e-mail]>; [e-mail]
> > > > > Cc: [e-mail]; [e-mail]
> > > > > Subject: Re: [Dots] Adoption call for
> > > > > draft-reddy-dots-home-network-04
> > > > >
> > > > > This email originated from outside of the organization. Do not
> > > > > click links
> > > > or
> > > > > open attachments unless you recognize the sender and know the
> > > > > content is safe.
> > > > >
> > > > > Re-,
> > > > >
> > > > > Please see inline.
> > > > >
> > > > > Cheers,
> > > > > Med
> > > > >
> > > > > > -----Message d'origine-----
> > > > > > De : Dots [mailto:[e-mail]] De la part de Valery
> > > > > > Smyslov Envoyé : mercredi 24 avril 2019 07:02 À : [e-mail] Cc :
> > > > > > [e-mail]; [e-mail] Objet : Re: [Dots]
> > > > > > Adoption call for draft-reddy-dots-home-network-04
> > > > > >
> > > > > > Hi,
> > > > > >
> > > > > > we received a lot of replies supporting adoption of the document.
> > > > > > So, the document is adopted. Authors, please re-submit it as
> > > > > > WG
> > draft.
> > > > > >
> > > > > > A couple of comments.
> > > > > > 1. The draft uses few times a keyword "MAY NOT". This
> > > > > > combination is
> > > not
> > > > > >      among the list of RFC requirement keywords (it is not
> > > > > > listed
> > neither
> > > > > >      in RFC2119, nor in RFC8174). If the intent was to use RFC
> > > > requirement
> > > > > >      language, then I'd suggest replacing it with one of MUST
> > > > > > NOT, SHALL NOT,
> > > > > >      SHOULD NOT. Otherwise please make it lowcase.
> > > > > >
> > > > >
> > > > > [Med] Good catch. Fixed.
> > > > >
> > > > > > 2. When describing transport, the draft allows both TLS and DTLS.
> > What
> > > > > >      makes me confusing is that the draft describes it several
> > > > > > times as "TCP/TLS or DTLS".
> > > > > >      Why TCP is ever mentioned here? We all know that TLS
> > > > > > usually runs
> > > > over
> > > > > >      TCP (however we now have QUICK) and DTLS runs over UDP.
> > > > > >      The way it is presented in the draft makes me think that
> > probably
> > > > > >      plain TCP is also allowed as a transport, but is seems to
> > contradict
> > > > > >      everything I read about DOTS. Am I missing something here?
> > > > > >
> > > > >
> > > > > [Med] Plain TCP is not allowed. The intent was to be explicit
> > > > > that there is
> > > > a
> > > > > reversal in both TCP and TLS layers, but as you rightfully
> > > > > raised this may
> > > > be
> > > > > confusing since, for the DOTS case, it is trivial that the
> > > > > reversal of TLS
> > > > roles
> > > > > implies the reversal of TCP ones.
> > > >
> > > > RESTCONF call home only reverses the TCP role but not the TLS
> > > > role. In DOTS case, the server has to initiate DTLS handshake for
> > > > UDP. To keep the roles same for TCP,  TLS handshake is also initiated by
> the server.
> > >
> > > [Med] You missed "for the DOTS case" in my previous reply :-)
> > >
> > > We do have the following in the draft:
> > >
> > >                    DOTS                                DOTS
> > >                   Server                              Client
> > >                     |                                    |
> > >                     |         1. (D)TLS connection       |
> > >                     |----------------------------------->|
> > >                     |         2. Mitigation request      |
> > >                     |<-----------------------------------|
> > >                     |                                    |
> > >
> > > That can be trivially expanded as follows for the TLS case:
> > >
> > >                    DOTS                                DOTS
> > >                   Server                              Client
> > >                     |                                    |
> > >                     |         1.1. TCP                   |
> > >                     |----------------------------------->|
> > >                     |         1.2. TLS                   |
> > >                     |----------------------------------->|
> > >                     |         2. Mitigation request      |
> > >                     |<-----------------------------------|
> > >                     |                                    |
> >
> > Okay.
> >
> > >
> > >
> > > As mentioned earlier, the use of TCP/TLS is OK but it may be
> > > confusing as initially raised by Valery.
> >
> > The updated text is not accurate if TCP is not covered, role reversal
> > at TLS does not mean role reversal at TCP.
> 
> [Med] The updated text is still fine (ref to Figure 1). We don't have any
> ambiguity in the procedure part with regards to TCP. We explicitly say the
> following:
> 
>        If TCP is used, the DOTS server begins by initiating a TCP
>        connection to the DOTS client.  The DOTS client MUST support
>        accepting TCP connections on the IANA-assigned port number
>        defined in Section 4.1, but MAY be configured to listen to a
>        different port number.  Using this TCP connection, the DOTS
>        server initiates a TLS connection to the DOTS client.
> 
> > Similar to (D)TLS, I prefer explicit text to say role reversal at TCP.
> 
> [Med] We already have such text (see the above excerpt).

[TR] Yes, but the updated sentences are incomplete/incorrect at various places. I have listed one of the inconsistencies below

   The one and only role reversal that
   occurs are at the TLS or DTLS layers; that is, the DOTS server acts
   as a DTLS client and the DOTS client acts as a DTLS server or the
   DOTS server acts as a TLS client and the DOTS client acts as a TLS
   server.  The DOTS server initiates TLS handshake or DTLS handshake to
   the DOTS client.

The above update means no role reversal at the TCP layer !

-Tiru

> 
>  The
> > security considerations section says " DOTS agents MUST authenticate
> > each other using (D)TLS before a DOTS signal channel session is
> > considered valid.", so clear text DOTS traffic is ruled out.
> 
> [Med] Fully agree.