Yes, but that’s a new precedent requiring the MR to store state. We should try to make it lighter weight. And you can’t do what you want on the MR, because its the MS’s OTK as spec’ed today that is passed to the ETR.
Dino > On Mar 31, 2020, at 4:58 PM, Joel M. Halpern <j...@joelhalpern.com> wrote: > > We could reuse the OTK directly. My actual inclination would be for the MR > to send back (via the ETR) some data which, when combined with the OTK, > produced a separate key for use with the notify messages. Clearly, the MR > would have to store whatever security key we want it to use as long as the > subscription persisted. > > Yours, > Joel > > On 3/31/2020 7:27 PM, Dino Farinacci wrote: >>> I may have missed something, but I think that in the case of the first >>> notify, it does actually start at the Itr. >>> Specifically, it starts with an ItR sending a subscribe request. The MS >>> responds to that with a notify. What I am suggesting is that (when >>> security is desired) the Itr includes the same kind of information in its >>> subscribe that goes into lisp-sec. And that the reply, instead of going >>> directly from the MS back to the ITR goes through the ETR so that the rest >>> of the lisp-sec procedures can be applied. >> Yes, and in that Subscribe-Request you can include an OTK. But that >> one-time-key would be used more than one time. To send the Map-Notify to >> reply with the RLOC-set to the ITR as well as acknowledger from the >> Map-Server that subscription has been accepted. But then the one-time-key >> would have to be *stored* in the Map-Server and then used later when the >> RLOC-set changes to send an unsolicited Map-Notify. So the one-time-key >> would be “two time” and we would set a precedent to make it no longer >> ephemeral. In previous cases, the OTK was not stored anywhere. >>> I would then use that as a bootstrap, putting necessary secrets to create >>> the key information so that the MS can sign and the ITR can verify future >>> notifies that go directly from the MS to the ITR. >> If the working group believes that the OTK should be stored and then used >> again, then both the Map-Server and ITR would have to store it. In the >> original case, the ITR stores the OTK only until the time a Map-Reply or >> Map-Notify is received. But the Map-Server would have to store it >> indefinintely (per ITR that subscribes). >> Dino >>> >>> Yours, >>> Joel >>> >>> On 3/31/2020 1:33 PM, Dino Farinacci wrote: >>>>> thinking about Alberto's request, and reading the document, I wondered if >>>>> the security could be improved by sending the first notify back via the >>>>> ETR, and coupling it to LISP-SEC to protect the information and provide >>>>> needed keys for further messages? It seems like we do need a way to >>>>> protect the notifications, and requiring associations from every ITR to >>>>> every MS who may provide notifications seems impossible. >>>> You can’t use LISP-SEC because the transactional nature of it starts with >>>> an ITR and a one-time-key, that is used to signed Map-Replies returning to >>>> it. >>>> For Map-Notify messages send from Map-Server via ETR, there would be no >>>> ITR one-time-key. And if the Map-Server used its own one-time-key, the ITR >>>> couldn’t derive it. Note with LISP-SEC the map-server one-time-key is >>>> derived from the ITR’s one-time-key in the Map-Request. >>>> Dino _______________________________________________ lisp mailing list lisp@ietf.org https://www.ietf.org/mailman/listinfo/lisp
