Re: [secdir] secdir review of draft-ietf-spring-segment-routing-13
Eric Rescorla <ekr@rtfm.com> Sat, 24 March 2018 11:39 UTC
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From: Eric Rescorla <ekr@rtfm.com>
Date: Sat, 24 Mar 2018 11:39:06 +0000
Message-ID: <CABcZeBNkZvmVA-DhyCL=1QFfC+atS3S5WCySa+Gosdpy3Te8nA@mail.gmail.com>
To: "Les Ginsberg (ginsberg)" <ginsberg@cisco.com>
Cc: Alissa Cooper <alissa@cooperw.in>, David Mandelberg <david+work@mandelberg.org>, "iesg@ietf.org" <iesg@ietf.org>, "secdir@ietf.org" <secdir@ietf.org>, "draft-ietf-spring-segment-routing.all@ietf.org" <draft-ietf-spring-segment-routing.all@ietf.org>
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Subject: Re: [secdir] secdir review of draft-ietf-spring-segment-routing-13
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On Sat, Mar 24, 2018 at 11:13 AM, Les Ginsberg (ginsberg) < ginsberg@cisco.com> wrote: > Eric – > > > > Alissa’s comments were addressed – and we have been waiting for a response > from her for nearly 3 months. > > See attached. > > You need to take this up with Alissa. -Ekr > Les > > > > > > *From:* Eric Rescorla <ekr@rtfm.com> > *Sent:* Saturday, March 24, 2018 3:40 AM > *To:* Les Ginsberg (ginsberg) <ginsberg@cisco.com> > *Cc:* David Mandelberg <david+work@mandelberg.org>; iesg@ietf.org; > secdir@ietf.org; draft-ietf-spring-segment-routing.all@ietf.org > > *Subject:* Re: secdir review of draft-ietf-spring-segment-routing-13 > > > > The DISCUSS on this document is being held by Alissa Cooper. > > https://datatracker.ietf.org/doc/draft-ietf-spring-segment-routing/ballot/ > > > > I would suggest responding to her points (there should be an associated > email thread) > > > > -Ekr > > > > > > On Fri, Mar 23, 2018 at 11:27 PM, Les Ginsberg (ginsberg) < > ginsberg@cisco.com> wrote: > > Hmmm...well if you look at https://datatracker.ietf.org/ > doc/draft-ietf-spring-segment-routing/ we see > > > > > > *Reviews* > > OPSDIR Last Call Review (of -13): Ready > <https://datatracker.ietf.org/doc/review-ietf-spring-segment-routing-13-opsdir-lc-ersue-2017-12-19/> > > SECDIR Last Call Review (of -13): Has Nits > <https://datatracker.ietf.org/doc/review-ietf-spring-segment-routing-13-secdir-lc-mandelberg-2017-11-18/> > > RTGDIR Telechat Review (of -13): Ready > <https://datatracker.ietf.org/doc/review-ietf-spring-segment-routing-13-rtgdir-telechat-hardwick-2017-12-12/> > > > > And then the SECDIR review link points to your review: > https://datatracker.ietf.org/doc/review-ietf-spring- > segment-routing-13-secdir-lc-mandelberg-2017-11-18/ > > > > So I don’t know what else needs to be done to clear this. > > > > Bruno? Rob? Can you help here? > > > > Les > > > > > -----Original Message----- > > > From: David Mandelberg <david+work@mandelberg.org> > > > Sent: Friday, March 23, 2018 4:18 PM > > > To: Les Ginsberg (ginsberg) <ginsberg@cisco.com>; iesg@ietf.org; > > > secdir@ietf.org; draft-ietf-spring-segment-routing.all@ietf.org > > > Subject: Re: secdir review of draft-ietf-spring-segment-routing-13 > > > > > > No worries about the delay. And I'm just a secdir reviewer, not an IESG > member, > > > so I can't do anything about a DISCUSS. > > > > > > On 03/23/2018 07:02 PM, Les Ginsberg (ginsberg) wrote: > > > > David - > > > > > > > > Yes - IGP specs have this. See (for example): > > > > > > > > https://tools.ietf.org/html/draft-ietf-isis-segment-routing-extensions > > > > -15#section-2.2.1 > > > > > > > > If this suffices please clear your DISCUSS on the draft. > > > > > > > > Again, apologies for the long delay in responding - it was not > intentional. > > > > > > > > Les > > > > > > > >> -----Original Message----- > > > >> From: David Mandelberg <david+work@mandelberg.org> > > > >> Sent: Friday, March 23, 2018 3:57 PM > > > >> To: Les Ginsberg (ginsberg) <ginsberg@cisco.com>; iesg@ietf.org; > > > >> secdir@ietf.org; draft-ietf-spring-segment-routing.all@ietf.org > > > >> Subject: Re: secdir review of draft-ietf-spring-segment-routing-13 > > > >> > > > >> Thanks, I didn't know it was in the IGP specs. If the usage you > > > >> describe would be clear to anybody using this, then I think you've > > > >> fully addressed my original comment. > > > >> > > > >> On 03/23/2018 06:43 PM, Les Ginsberg (ginsberg) wrote: > > > >>> David - > > > >>> > > > >>> Thanx for the very prompt response. > > > >>> > > > >>> If a controller (for example) is defining a SID stack for an SR > > > >>> Policy, it can > > > >> choose to use an Adj-SID which is advertised as Persistent and be > > > >> confident that the SID will not be reused for some other purpose no > > > >> matter what happens on the owning node. > > > >>> > > > >>> BTW, the flag isn’t new - it has been part of the IGP specifications > > > >>> for quite a > > > >> long while. It just wasn't mentioned in the SR Architecture in > earlier versions. > > > >>> > > > >>> HTH > > > >>> > > > >>> Les > > > >>> > > > >>>> -----Original Message----- > > > >>>> From: David Mandelberg <david+work@mandelberg.org> > > > >>>> Sent: Friday, March 23, 2018 3:17 PM > > > >>>> To: Les Ginsberg (ginsberg) <ginsberg@cisco.com>; iesg@ietf.org; > > > >>>> secdir@ietf.org; draft-ietf-spring-segment-routing.all@ietf.org > > > >>>> Subject: Re: secdir review of draft-ietf-spring-segment-routing-13 > > > >>>> > > > >>>> Hi, > > > >>>> > > > >>>> How will the indication of persistence be used? I scanned the > > > >>>> changes from -13 to -15, but I didn't notice any other text about > the new > > > flag. > > > >>>> > > > >>>> On 03/23/2018 06:34 AM, Les Ginsberg (ginsberg) wrote: > > > >>>>> David - > > > >>>>> > > > >>>>> Apologies. It appears that I neglected to respond to this old > > > >>>>> review comment. > > > >>>>> > > > >>>>> This was not intentional. Authors actively discussed your comment > > > >>>>> promptly and we did add text in V14 of the draft to address this > point: > > > >>>>> > > > >>>>> Please see: > > > >>>>> https://tools.ietf.org/html/draft-ietf-spring-segment-routing-15#s > > > >>>>> ec > > > >>>>> ti > > > >>>>> on-3.4 > > > >>>>> > > > >>>>> /o Indication whether the Adj-SID is persistent across control > > > >>>>> plane/ > > > >>>>> > > > >>>>> / restarts. Persistence is a key attribute in ensuring that > > > >>>>> an SR/ > > > >>>>> > > > >>>>> / Policy does not temporarily result in misforwarding due to/ > > > >>>>> > > > >>>>> / reassignment of an Adj-SID./ > > > >>>>> > > > >>>>> // > > > >>>>> > > > >>>>> Please let us know if this adequately addresses your comment. > > > >>>>> > > > >>>>> Again, apologies for the long delay. > > > >>>>> > > > >>>>> Les > > > >>>>> > > > >>>>> > -----Original Message----- > > > >>>>> > > > >>>>> > From: David Mandelberg <david@mandelberg.org> > > > >>>>> > > > >>>>> > Sent: Thursday, November 02, 2017 10:53 AM > > > >>>>> > > > >>>>> > To: iesg@ietf.org; secdir@ietf.org; > > > >>>>> draft-ietf-spring-segment- > > > >>>>> > > > >>>>> > routing.all@ietf.org > > > >>>>> > > > >>>>> > Subject: secdir review of > > > >>>>> draft-ietf-spring-segment-routing-13 > > > >>>>> > > > >>>>> > > > > >>>>> > > > >>>>> > I have reviewed this document as part of the security > > > >>>>> directorate's ongoing > > > >>>>> > > > >>>>> > effort to review all IETF documents being processed by the > IESG. > > > >>>>> These > > > >>>>> > > > >>>>> > comments were written primarily for the benefit of the > > > >>>>> security area directors. > > > >>>>> > > > >>>>> > Document editors and WG chairs should treat these comments > > > >>>>> just like any > > > >>>>> > > > >>>>> > other last call comments. > > > >>>>> > > > >>>>> > > > > >>>>> > > > >>>>> > The summary of the review is Ready with nits. > > > >>>>> > > > >>>>> > > > > >>>>> > > > >>>>> > This document affects routing within a trusted domain, and > > > >>>>> the security > > > >>>>> > > > >>>>> > considerations section adequately talks about filtering at > > > >>>>> the border of a trusted > > > >>>>> > > > >>>>> > domain. > > > >>>>> > > > >>>>> > > > > >>>>> > > > >>>>> > I do have one question about something I didn't see in the > > > >>>>> document, what > > > >>>>> > > > >>>>> > happens when SIDs change while packets are in transit? Here's > > > >>>>> a hypothetical > > > >>>>> > > > >>>>> > situation that could be bad for security, but I'm not sure > > > >>>>> whether or not it could > > > >>>>> > > > >>>>> > happen: 1. An internal node calculates an SR Policy and sends > > > >>>>> out a packet that > > > >>>>> > > > >>>>> > will eventually egress towards a BGP peer. 2. Multiple links > > > >>>>> on the BGP router go > > > >>>>> > > > >>>>> > down and then back up, but are allocated different PeerAdj > > > >>>>> SIDs than they had > > > >>>>> > > > >>>>> > before. 3. The packet reaches the BGP router, but egresses to > > > >>>>> the wrong BGP > > > >>>>> > > > >>>>> > peer because the original PeerAdj SID is now mapped to a > > > >>>>> different PeerAdj > > > >>>>> > > > >>>>> > segment. > > > >>>>> > > > >>>>> > > > > >>>>> > > > >>>>> > -- > > > >>>>> > > > >>>>> > Freelance cyber security consultant, software developer, and > > > >>>>> more > > > >>>>> > > > >>>>> > https://david.mandelberg.org/ > > > >>>>> > > > >>>> > > > >>>> > > > >>>> -- > > > >>>> Freelance cyber security consultant, software developer, and more > > > >>>> https://david.mandelberg.org/ > > > >> > > > >> > > > >> -- > > > >> Freelance cyber security consultant, software developer, and more > > > >> https://david.mandelberg.org/ > > > > > > > > > -- > > > Freelance cyber security consultant, software developer, and more > > > https://david.mandelberg.org/ > > > > > ---------- Forwarded message ---------- > From: Alvaro Retana <aretana.ietf@gmail.com> > To: "Les Ginsberg (ginsberg)" <ginsberg@cisco.com>, Alissa Cooper < > alissa@cooperw.in>, The IESG <iesg@ietf.org> > Cc: "spring@ietf.org" <spring@ietf.org>, "spring-chairs@ietf.org" < > spring-chairs@ietf.org>, "draft-ietf-spring-segment-routing@ietf.org" < > draft-ietf-spring-segment-routing@ietf.org>, "martin.vigoureux@nokia.com" > <martin.vigoureux@nokia.com> > Bcc: > Date: Thu, 11 Jan 2018 21:58:49 +0000 > Subject: RE: Alissa Cooper's Discuss on > draft-ietf-spring-segment-routing-13: (with DISCUSS and COMMENT) > Alissa: > > Hi! > > Any thoughts on the update to this document? > > Thanks! > > Alvaro. > > On December 20, 2017 at 6:18:13 PM, Les Ginsberg (ginsberg) ( > ginsberg@cisco.com) wrote: > > Alissa - > > Thanx for the review. > V14 has been published and it attempts to address the Security concerns > raised by you and others. > Look forward to your feedback. > > Inline. > > > -----Original Message----- > > From: Alissa Cooper [mailto:alissa@cooperw.in] > > Sent: Wednesday, December 13, 2017 10:42 AM > > To: The IESG <iesg@ietf.org> > > Cc: draft-ietf-spring-segment-routing@ietf.org; aretana.ietf@gmail.com; > > spring-chairs@ietf.org; martin.vigoureux@nokia.com; spring@ietf.org > > Subject: Alissa Cooper's Discuss on draft-ietf-spring-segment-routing-13: > > > (with DISCUSS and COMMENT) > > > > Alissa Cooper has entered the following ballot position for > > draft-ietf-spring-segment-routing-13: Discuss > > > > When responding, please keep the subject line intact and reply to all > email > > addresses included in the To and CC lines. (Feel free to cut this > introductory > > paragraph, however.) > > > > > > Please refer to https://www.ietf.org/iesg/statement/discuss-criteria. > html > > for more information about IESG DISCUSS and COMMENT positions. > > > > > > The document, along with other ballot positions, can be found here: > > https://datatracker.ietf.org/doc/draft-ietf-spring-segment-routing/ > > > > > > > > ---------------------------------------------------------------------- > > DISCUSS: > > ---------------------------------------------------------------------- > > > > I ended up reading draft-ietf-6man-segment-routing-header in tandem > with > > this document, and I have a question arising out of that. The trust > model for > > SRv6 outlined in this document appears to be one of reliance on the fact > that > > an SRH will only ever be inserted and appear within a single > administrative > > domain. > > But Section 5.2.2 of draft-ietf-6man-segment-routing-header talks about > an > > SRH being inserted by a device outside of the segment routing domain. > > Which is correct? I think this is an important question because the > whole > > trust model for the SR information seems to rely on out-of-band trust > > between participating nodes. > > > > I also think this is important because there is no discussion in this > document > > of the impact of the inclusion of the SR metadata on the fingerprinting > of the > > device that inserted it. Section 5.1.4 of draft-ietf-6man-segment-routing- > > > header sort of alludes to this but seems to equate the capabilities of > an > > active attacker (who can conduct a traceroute) with a passive attacker > who > > could passively collect topology/fingerprinting information simply by > > observing SRHes flowing by on the network. If the limitation to a single > > administrative domain is meant to prevent such a passive attack (not > sure if > > that is really true, but perhaps the document assumes it?), that's > another > > reason that the existence of such a limitation needs to be clarified. > > > > > [Les:] We share a common concern regarding trust issues. The architecture > draft speaks to the default policy of only allowing trusted sources to > insert SRH. > The 6man draft currently discusses exceptions under the protection of > authentication. I don’t see that as a contradiction. > The risk/reward of allowing such exceptions can (and should) be discussed > in the review of the 6man draft, but I am not convinced the architecture > draft needs to speak to this since it is a clearly stated exception to the > base trust model. > > The point that SR is intended to operate within a trusted domain has been > clarified/reemphasized in the Security section changes. > > Les > > > > > ---------------------------------------------------------------------- > > COMMENT: > > ---------------------------------------------------------------------- > > > > > > Per my DISCUSS comment, I think this document needs to include some > > considerations concerning the additional metadata that SRv6 adds to the > > packet. > > This has implications not just for passive observers but also for any > node that > > logs the SRH. > > > > >
- [secdir] secdir review of draft-ietf-spring-segme… David Mandelberg
- Re: [secdir] secdir review of draft-ietf-spring-s… Les Ginsberg (ginsberg)
- Re: [secdir] secdir review of draft-ietf-spring-s… David Mandelberg
- Re: [secdir] secdir review of draft-ietf-spring-s… Les Ginsberg (ginsberg)
- Re: [secdir] secdir review of draft-ietf-spring-s… David Mandelberg
- Re: [secdir] secdir review of draft-ietf-spring-s… Les Ginsberg (ginsberg)
- Re: [secdir] secdir review of draft-ietf-spring-s… David Mandelberg
- Re: [secdir] secdir review of draft-ietf-spring-s… Les Ginsberg (ginsberg)
- Re: [secdir] secdir review of draft-ietf-spring-s… Eric Rescorla
- Re: [secdir] secdir review of draft-ietf-spring-s… Les Ginsberg (ginsberg)
- Re: [secdir] secdir review of draft-ietf-spring-s… Eric Rescorla
- Re: [secdir] secdir review of draft-ietf-spring-s… Benjamin Kaduk
- Re: [secdir] secdir review of draft-ietf-spring-s… David Mandelberg
- Re: [secdir] secdir review of draft-ietf-spring-s… Benjamin Kaduk
- Re: [secdir] secdir review of draft-ietf-spring-s… Tero Kivinen
- Re: [secdir] secdir review of draft-ietf-spring-s… Benjamin Kaduk
- Re: [secdir] secdir review of draft-ietf-spring-s… David Mandelberg
- Re: [secdir] secdir review of draft-ietf-spring-s… Benjamin Kaduk