Re: [secdir] Secdir review of draft-ietf-trill-multilevel-unique-nickname-05
"Zhangmingui (Martin)" <zhangmingui@huawei.com> Mon, 05 March 2018 03:49 UTC
Return-Path: <zhangmingui@huawei.com>
X-Original-To: secdir@ietfa.amsl.com
Delivered-To: secdir@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 66519124C27; Sun, 4 Mar 2018 19:49:56 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.23
X-Spam-Level:
X-Spam-Status: No, score=-4.23 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_PASS=-0.001, T_RP_MATCHES_RCVD=-0.01, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Ulmm5KR0xrlb; Sun, 4 Mar 2018 19:49:53 -0800 (PST)
Received: from huawei.com (lhrrgout.huawei.com [194.213.3.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 8C46D1241F3; Sun, 4 Mar 2018 19:49:53 -0800 (PST)
Received: from LHREML712-CAH.china.huawei.com (unknown [172.18.7.106]) by Forcepoint Email with ESMTP id 3A200BFE55C37; Mon, 5 Mar 2018 03:49:50 +0000 (GMT)
Received: from NKGEML411-HUB.china.huawei.com (10.98.56.70) by LHREML712-CAH.china.huawei.com (10.201.108.35) with Microsoft SMTP Server (TLS) id 14.3.382.0; Mon, 5 Mar 2018 03:49:51 +0000
Received: from NKGEML515-MBX.china.huawei.com ([fe80::a54a:89d2:c471:ff]) by nkgeml411-hub.china.huawei.com ([10.98.56.70]) with mapi id 14.03.0361.001; Mon, 5 Mar 2018 11:49:47 +0800
From: "Zhangmingui (Martin)" <zhangmingui@huawei.com>
To: Donald Eastlake <d3e3e3@gmail.com>, Roman Danyliw <rdd@cert.org>
CC: "iesg@ietf.org" <iesg@ietf.org>, "secdir@ietf.org" <secdir@ietf.org>, "draft-ietf-trill-multilevel-unique-nickname.all@ietf.org" <draft-ietf-trill-multilevel-unique-nickname.all@ietf.org>
Thread-Topic: Secdir review of draft-ietf-trill-multilevel-unique-nickname-05
Thread-Index: AdOyXwuroB0yJVJhRMeJvvm4FEzIkQBSKNIAACNBjRA=
Date: Mon, 05 Mar 2018 03:49:47 +0000
Message-ID: <4552F0907735844E9204A62BBDD325E7AAFE1B27@NKGEML515-MBX.china.huawei.com>
References: <359EC4B99E040048A7131E0F4E113AFC0137F6E1D1@marathon> <CAF4+nEHUNkiXOJrKpeb-esX75mH6xC6_C1scR4Mf8dOugRHohA@mail.gmail.com>
In-Reply-To: <CAF4+nEHUNkiXOJrKpeb-esX75mH6xC6_C1scR4Mf8dOugRHohA@mail.gmail.com>
Accept-Language: en-US, zh-CN
Content-Language: zh-CN
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [10.111.146.93]
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
MIME-Version: 1.0
X-CFilter-Loop: Reflected
Archived-At: <https://mailarchive.ietf.org/arch/msg/secdir/1Dw-CTuNzsd2ThVQl07Q70GOp_Q>
Subject: Re: [secdir] Secdir review of draft-ietf-trill-multilevel-unique-nickname-05
X-BeenThere: secdir@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: Security Area Directorate <secdir.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/secdir>, <mailto:secdir-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/secdir/>
List-Post: <mailto:secdir@ietf.org>
List-Help: <mailto:secdir-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/secdir>, <mailto:secdir-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 05 Mar 2018 03:49:56 -0000
Hi Donald, Roman, Thanks a lot for the review! The comments have been incorporated in the 06 version which has been uploaded. Thanks, Mingui > -----Original Message----- > From: Donald Eastlake [mailto:d3e3e3@gmail.com] > Sent: Monday, March 05, 2018 2:58 AM > To: Roman Danyliw <rdd@cert.org> > Cc: iesg@ietf.org; secdir@ietf.org; > draft-ietf-trill-multilevel-unique-nickname.all@ietf.org > Subject: Re: Secdir review of draft-ietf-trill-multilevel-unique-nickname-05 > > Hi Roman, > > Thanks for doing a review. See responses below. > > On Fri, Mar 2, 2018 at 9:00 PM, Roman Danyliw <rdd@cert.org> wrote: > > Reviewer: Roman Danyliw > > Review result: Ready with nits > > > > 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. > > > > My feedback is as follows: > > > > (1) Section 4.1, Multilevel TRILL Basics, Page 8 > > > > Thus Level 1 link state > > information stays within a Level 1 area and Level 2 link state > > information stays in Level 2 unless there are specific provisions for > > leaking (copying) information between levels. > > > > ** What are these provisions where such leakage of information should occur > beyond expected routing behavior? > > Typically "link state" information stays within a Level 1 area or within the Level > 2 routers. Occasionally there is information that it is desirable to flood > throughout the domain at both Level 1 and Level 2. IS-IS "link state" > information is in the form of TLVs. Typically this domain wide flooding is > accomplished by using two flags in the value portion of the TLV. One flag > indicates the the TLV is to be flooded domain wide while the other is initially > zero and is set when the TLV is flooded from Level 2 to Level 1 -- this second flag > is to stop a TLV from being flooded from Level 2 to Level 1 and then back to > Level 2 again resulting in TLV looping. See, for example, the IS-IS Router > Capabilities TLV D and S flags as specified in Section 2 of RFC 7981. This is all > standard IS-IS machinery that someone familiar with IS-IS would know -- there > is nothing TRILL specific about it. > > > (2) Section 4.2, Nickname Allocation, Page 8-9. > > > > Level 2 RBridges contend for nicknames in the range from 0xF000 > > through 0xFBFF the same way as specified in [RFC6325], using Level 2 > > LSPs. The highest priority border router for a Level 1 area should > > contend with others in Level 2 for smallish blocks of nicknames for > > the range from 0x0001 to 0xEFFF. Blocks of 64 aligned on multiple of > > 64 boundaries are RECOMMENDED in this document. > > > > ** This text provides guidance to allocate nicknames from the range 0x0001 - > 0xFBFF (0x0001 - 0xEFFF and 0xF000 - 0xFBFF); and Section 3.7 of RFC6325 says > that 0xFFC0 - 0xFFFF and 0x0 are reserved. Collectively, these two documents > leave the range of 0xFC00 - 0xFFBF unspecified. If that's intentional, describe > how these values should be handled. Or, perhaps there a typo and L2 Rbridges > should allocate from 0xF000 - 0xFFBF (i.e., s/0xFBFF/0xFFBF/)? > > I believe it's a typo and is should by 0xF000 - 0xFFBF. > > > ** (Editorial) The language "smallish blocks of nicknames" seems imprecise. > > I think we could just delete the word "smallish". > > > (3) Section 6, Security Considerations, Page 12. > > > > With TRILL multilevel, flooding of control traffic for link state > > information of Level 1 and Level 2 is separated. This addresses the > > TRILL scalability issues as specified in Section 2 of [RFC8243] and > > also confines the effective scope of possible malicious events. > > > > ** Per the sentence "With TRILL ... is separated", I recommend > > clarifying the language on what and in what way there is separation > > This is basic to multilevel IS-IS and anyone familiar with that would understand. > We could add a reference to IS-IS. > > > ** Per the follow-up sentence, "... also confines the effective scope of > possible malicious events", I recommend discussing in more detail how the > scope of malicious events is reduced with this approach. > > I suggest the following replacement text: > > Since TRILL multilevel uses the existing IS-IS multilevel facilities [IS-IS], > flooding of control traffic for link state information is automatically confined to > a Level 1 area or to Level 2 except (for limited types of information that can be > specifically flagged for wider flooding). This addresses the TRILL scalability > issues as specified in Section 2 of [RFC8243] and also, except of the wider > flooding case, this confines the scope of the effects of malicious events that > could be communicated through the link state. > > > (4) Section 6, Security Considerations, Page 12. > > > > However, due to the nature that unique nickname areas share a unique > > nickname space, border RBridges still have to leak nickname > > information between levels. For this purpose, border RBridges need to > > fabricate the nickname announcements as specified in Section 4.3. > > > > ** As it is raised as an issue with a mitigation, I recommend articulating the > implication of leaking nicknames across levels. > > Since nicknames must be unique across the multi-level domain, and nicknames > in TRILL are auto-allocated, clearly RBridges inside an area need to know what > nicknames are in use, which is the effect and purpose of leaking nickname claim > information across levels. I suggest the following wording: > > However, due to the nature that unique nickname areas share a common > nickname space, border RBridges still have to leak nickname information > between levels. Such leaking means that nickname related events in one area > can affect other areas. For this purpose, border RBridges need to fabricate the > nickname announcements as specified in Section 4.3. > > > (5) Section 6, Security Considerations, Page 12. > > > > Malicious devices may also fake the NickBlockFlags APPsub-TLV to > > announce a range of nicknames. By doing this, the attacker can attract > > TRILL data packets that are originally to reach a bunch of other > > RBridges. > > > > ** Recommend articulating the implications of a rogue device changing the > path -- it might deny service, expose traffic to inspection, etc. > > This is not that much different from an RBridge announcing low cost to some > MAC address to attract data packets. It is typical that all routers in some > routing domain have to be, to a reasonable extent, trusted since there is a > large variety of information they could maliciously announce to cause problems. > If a rogue router makes false announcements to attract traffic, typically the > traffic goes to that router and not to the intended destination. Anyone familiar > with common routing techniques would be aware of this. > > > ** (Editorial) Recommend alternate language for the colloquial "... bunch of > other RBridges" > > bunch -> number > > > (6) Section 6, Security Considerations, Page 12. > > > > For this reason, RBridges SHOULD be configured to include the IS-IS > > Authentication TLV (10) in the IS-IS PDUs that contains the > > NickBlockFlags APPsub-TLV, so that IS-IS security ([RFC5304] > > [RFC5310]) can be used to secure the network. > > > > ** Should a preference be expressed for RFC5310 over RFC5304? To quote > RFC5310, "[while at the time of this writing there are no openly published > attacks on the HMAC-MD5 mechanism, some reports ([Dobb96a], [Dobb96b]) > create concern about the ultimate strength of the MD5 cryptographic hash > function." > > I would agree that RFC 5310 security is superior to RFC 5304 security. > Perhaps references to 5304 can be removed. > > > ** Recommend being more specific with the language "to secure the > network". Perhaps "For this reason, RBridges SHOULD authenticate their > peer by using the IS-IS Authentication TLV (10) in the IS-IS PDUs that contains > the NickBlockFlags APPsub-TLV." > > Suggest replacing "to secure the network" with "to authenticate those PDUs > and discard them if they are forged." > > > (7) Section 6, Security Considerations, Page 12. > > > > If border RBridges do not prune multi-destination distribution tree > > traffic in Data Labels that are configured to be area local, then > > traffic that should have been contained within an area might be > > wrongly delivered to end stations in that Data Label in other areas. > > This would generally violate security constraints. > > > > ** Recommend being more specific on the security constraints being > > violated > > OK. > > Thanks, > Donald > =============================== > Donald E. Eastlake 3rd +1-508-333-2270 (cell) > 155 Beaver Street, Milford, MA 01757 USA d3e3e3@gmail.com
- [secdir] Secdir review of draft-ietf-trill-multil… Roman Danyliw
- Re: [secdir] Secdir review of draft-ietf-trill-mu… Donald Eastlake
- Re: [secdir] Secdir review of draft-ietf-trill-mu… Zhangmingui (Martin)
- Re: [secdir] Secdir review of draft-ietf-trill-mu… Roman Danyliw
- Re: [secdir] Secdir review of draft-ietf-trill-mu… Roman Danyliw
- Re: [secdir] Secdir review of draft-ietf-trill-mu… Zhangmingui (Martin)
- Re: [secdir] Secdir review of draft-ietf-trill-mu… Kathleen Moriarty
- Re: [secdir] Secdir review of draft-ietf-trill-mu… Donald Eastlake
- Re: [secdir] Secdir review of draft-ietf-trill-mu… Roman Danyliw