Re: [i2rs] Kathleen Moriarty's Discuss on draft-ietf-i2rs-protocol-security-requirements-07: (with DISCUSS and COMMENT)

[Kathleen Moriarty <[e-mail]>]

I think there are some easy tweaks that could make everyone happy.  We
should be focusing on MTI, not MTU for requirements so that operators
can make decisions as needed.  I think we can all agree with that
statement.  We are worried about a few areas of text in the document,
namely where the data model can trigger the use of an insecure
transport.  The default is a secure transport for the protocol, so
that is MTI across the board.  One of the sections that causes concern
is the following:

Section 3: (I think the latest proposed text)

   I2RS allows the use of an insecure transport for portions of data
   models that clearly indicate the use of an insecure transport.
   Operators deploying I2RS must determine if they want to populate and
   deploy the portions of the data model which use insecure transports.


Which doesn't exactly meet the stated requirement in Section 3.2:

In Section 3.2 in version -08.txt

   SEC-REQ-08: The I2RS protocol MUST be able to transfer data over a
   secure transport and optionally MAY be able to transfer data over a
   non-secure transport.  A secure transport MUST provide data
   confidentiality, data integrity, and replay prevention.

I think if we reword the text in section 3 as follows, the requirement
for support of a secure transport will be clear, a way to mark the
data model for the possible use of insecure transport is possible
(decision of the operator).

How about:
   I2RS allows the use of an insecure transport for portions of data
   models that clearly indicate data confidentiality and integrity
protection may not be necessary.
   Operators deploying I2RS must determine if they want to populate and
   deploy the portions of the data model with a configuration option
to use insecure transports.

I understand this changes your requirements a bit and your
implementation, but is this a way that we could allow some operators
to operate in a secure mode for this data if they choose and also
allow MTU to be less than the default?

If that's agreeable - with the other ADs too - then some more text in
section 3.2 needs to be tweaked in a similar way.

The text in section 3.2 is closer to what I am proposing, you have the sentence:

   A non-secure transport can be used for publishing telemetry data or
   other operational state that was specifically indicated to non-
   confidential in the data model in the Yang syntax.

This talks about the data being marked in terms of a need for
confidentiality (should be integrity too as I could corrupt a clear
text stream in a way that is not detectable) instead of explicitly
stating that the transport should be insecure.  If the data model had
a attribute that had this marking (operator driven), I think that's an
improvement.

How about:

   A non-secure transport can be used for publishing telemetry data or
   other operational state that was specifically indicated as non-
   confidential and does not require integrity protection through an
   option provided in the data model.

I think this text allows for the WG goal of using a data model to
indicate the transport option, but for it to be an operator driven
decision in case some operators prefer to use transport encryption for
this section of the data model... or things change and they all decide
this is a good idea.

I'll get back to the other responses to my comments and discuss in a
separate message (possibly tomorrow).

If this alters discussions from other threads, please point me to the
thread and I'll catch up.

Thanks,
Kathleen

On Thu, Aug 18, 2016 at 4:05 PM, Susan Hares <[e-mail]> wrote:
> Andy:
>
>
>
> If we create a yang data model that is insecure, and mount on another data
> model – does it have the same issue as module augmentation?   Of course, we
> could create a mount point for all insecure data modules, and all data
> placed under that mount point – would be insecure.
>
>
>
> For the BGP route-views use case, this would make it clear that data had to
> be transformed to be insecure transmission.
>
>
>
> Sue
>
>
>
> From: Andy Bierman [mailto:[e-mail]]
> Sent: Thursday, August 18, 2016 4:02 PM
>
>
> To: Susan Hares
> Cc: Alissa Cooper; Joel Halpern; [e-mail]; Juergen Schoenwaelder;
> [e-mail]; Kathleen Moriarty; IESG; Jeffrey Haas;
> [e-mail]
> Subject: Re: [i2rs] Kathleen Moriarty's Discuss on
> draft-ietf-i2rs-protocol-security-requirements-07: (with DISCUSS and
> COMMENT)
>
>
>
>
>
>
>
> On Thu, Aug 18, 2016 at 12:44 PM, Susan Hares <[e-mail]> wrote:
>
> Andy:
>
>
>
> Thank you – I thought it was on whether we could implement insecure
> transport in a Yang module.
>
>
>
> The requirement text you are working with is:
>
>
>
>    SEC-REQ-08: The I2RS protocol MUST be able to transfer data over a
>    secure transport and optionally MAY be able to transfer data over a
>    non-secure transport.
>
>
>
> I do not understand why approving the ok for non-secure transport for some
> modules means the following to you:
>
>
>
> “ the IETF needs to agree that there could never possibly be any deployment
> that would not want to allow exposure of the data.
>
> Not now. Not 20 years from now.”
>
>
>
>
>
>
>
> As I understand it, this requirement has another requirement associated with
> it
>
> that says the data has to be identified as OK-for-nonsecure-transport.
>
>
>
> An extension in the data model says that all instances of the object in
>
> all possible deployments cannot be considered sensistive and therefore
>
> needs disclosure protection.
>
>
>
> It may seem like even a simple octet counter is safe to send in the clear,
>
> but not if that opens up correlation attacks.  (e.g., I can send data to
> some
>
> host.  I can see that index 455992 is incrementing the in-octets counters
>
> in a way that strongly correlates to my test traffic.  Therefore I can learn
>
> that arbitrary index 455992 is really John Doe or really suite #14, etc.
>
>
>
>
>
> I had thought that the security-directorate and other reviewers would look
> at each module that is insecure, and  consider whether it was reasonable for
> the use case at this time.   This is what I understood from Russ Housley’s
> first review of this technology.  Since like you, I believe the operator is
> going to  configure what modules are allowed on systems.   I agree that this
> requirement provides a full scope of the work, but implementers will require
> network operators to configure these features on.
>
>
>
> Sue
>
>
>
> Andy
>
>
>
>
>
>
>
> From: Andy Bierman [mailto:[e-mail]]
> Sent: Thursday, August 18, 2016 2:53 PM
> To: Susan Hares
> Cc: Alissa Cooper; Joel Halpern; [e-mail]; Juergen Schoenwaelder;
> [e-mail]; Kathleen Moriarty; IESG; Jeffrey Haas;
> [e-mail]
> Subject: Re: [i2rs] Kathleen Moriarty's Discuss on
> draft-ietf-i2rs-protocol-security-requirements-07: (with DISCUSS and
> COMMENT)
>
>
>
> Hi,
>
>
>
> I did not think Juergen's comment was about running code.
>
>
>
> In order for a data node to get the "ok-for-nonsecure-transports" approval
>
> in an IETF module, the IETF needs to agree that there could never possibly
> be
>
> any deployment that would not want to allow exposure of the data.
>
> Not now. Not 20 years from now.
>
>
>
> I can see a vendor making that decision for their own proprietary modules,
>
> but it seems less likely for standard modules.
>
>
>
> Seems like the operator is going to have to configure what is allowed
>
> for nonsecure transport anyway, so just let them decide.
>
> I don't really object to the extension or the requirement.
>
> It doesn't help much but it doesn't hurt much either.
>
>
>
>
>
> Andy
>
>
>
>
>
>
>
> On Thu, Aug 18, 2016 at 11:35 AM, Susan Hares <[e-mail]> wrote:
>
> Alissa:
>
> Just a little input you may not know.  My background is 15 years (1995-2010)
> developing a routing/switching platform (denoted as GateD) which was sold to
> over 200 companies.   We developed XML and a binary XML based product that
> configured this product.  It could do 100K configuration lines and reboot in
> less than a second on most hardware.  We also provide status messages in
> secure streams and non-secure streams.    I sold early version of this code
> to companies that Alia has worked for  - so she has personal viewed the
> code.   At the height of our work, our development team ran to 50 people
> which I directed (First as VP of Engineering, and then as CTO). It is due to
> this level of experience that Alia selected me for the co-chair.   Russ
> White has understood Cisco's process, and has also directed software
> development teams for routing.
>
> In order to freshen my direct experience with I2RS on open source work, I am
> working on a publically available work in Quagga based on the confD product
> suggested by Cisco.
>
> In contrast, Juergen is a university professor who has worked on
> proto-types.   He is not working on an implementation.   I hope he will.
>
> I hope you will consider this background in my response to your comments
> below.
>
> Sue
>
>
> -----Original Message-----
> From: Alissa Cooper [mailto:[e-mail]]
> Sent: Thursday, August 18, 2016 12:54 PM
> To: Joel Halpern
> Cc: Susan Hares; Juergen Schoenwaelder; [e-mail]; [e-mail];
> Kathleen Moriarty; IESG; [e-mail];
> [e-mail]
> Subject: Re: [i2rs] Kathleen Moriarty's Discuss on
> draft-ietf-i2rs-protocol-security-requirements-07: (with DISCUSS and
> COMMENT)
>
> Jumping in here because this is relevant to my DISCUSS, hope nobody minds
> (but if you do, I can go back to the other thread).
>
>>> On Aug 18, 2016, at 10:30 AM, Joel Halpern <[e-mail]>
>>> wrote:
>>>
>>> Let me try a different take approach to this particular question.
>>>
>>> Let me start by putting aside the question of where things are marked,
>>> and come back to that afterwards.
>>>
>>> There are a number of cases that I2RS has been asked to cover of high
>>> rate telemetry data.  This may be BGP update information, it may be frequent
>>> information about line card activity.  There are other cases, some of which
>>> have been documented.
>>>
>>> While not completely insensitive, the operators have made clear that they
>>> see protecting this data as unnecessary.  While I would hope over time to
>>> move to a domain where all of it is protect, that is not trivial.  As the
>>> I2RS Architecture points out, it is expected that what we describe as a
>>> single I2RS >communication between a client and agent is actually associated
>>> with multiple channels of communication.
>>>
>>> Now, if you want to say that the I2RS protocol requirements cannot allow
>>> for unprotected channels, I guess we have disconnect between the IESG and
>>> the WG.
>>>
>>> If we say that we can allow for unprotected channels, we then get to the
>>> question of which data can be sent over such channels.  While
>>> architecturally I agree with Juergen that the model is a bad place to
>>> specify it, the obverse is also true.  Not having some limits on what can be
>>> sent unprotected >causes concern about insufficient protection.  If I recall
>>> correctly, earlier security reviews called us to task for being too broad in
>>> what we allowed.
>>>
>>> So, if the IESG wants us to just allow it anywhere, because the model is
>>> an awkward place to define the limitation, I can live with that.  What I
>>> can't live with is being told both that the model is a bad place to define
>>> it and that there must be restrictions on what is sent unprotected,
>>> without any proposal on how we are to move forward.
>
>> Thank you Joel, this explanation helps me a lot. I think there is a
>> disconnect about how the restrictions are expressed. From reading the email
>> traffic about this document, it strikes me that trying to express the
>> restrictions programmatically doesn’t make much sense in this case.
>> I agree with Juergen that it will be challenging to make a judgment a
>> priori in order to bake a restriction into a data model, because data that
>> is considered sensitive enough to warrant a secure transport in one
>> deployment may not be considered sensitive in another deployment.
>> So for any data elements where there is any question at all about whether
>> they might be sensitive (i.e., any data elements that are not already
>> routinely made public),
>> I would expect data model authors to end up indicating that they may be
>> sent over either secure or insecure transport, which renders the indication
>> not useful.
>> Perhaps it would make more sense then to just enumerate in the text the
>> cases that motivate the inclusion of protocol support for insecure
>> transport:
>>
>> 1. For conveyance of information that is already routinely made public.
>> 2. For line card activity data where there is no likely upgrade path to
>> support secure transports in the foreseeable future.
>>
>> Then the normative requirements would be on clients and agents to use
>> secure transports unless those clients and agents are deployed where either
>> of the operational circumstances above necessitate otherwise.
>> Alissa
>
> Point 1:
> I disagree with Juergen on the difficulty in specifying the sections of the
> yang modules.  I have provided a suggested solution in:
> https://tools.ietf.org/html/draft-hares-i2rs-protocol-strawman-03#section-4.5.2.
>
> Given the mount schema functionality, we can mount ephemeral state module
> which augment non-ephemeral state modules which are "in-secure only".
>
> Point 2:
> I am willing to put an enumeration of the use cases in the protocol
> requirement, but I would like to understand the purpose for the enumeration.
> We are not doing a use case, but a requirements document.  This information
> appears to be a "use case" rather than a technical description.   What
> purpose are you looking for this enumeration to server.  Are you looking for
> the enumeration in SEC-REQ-08?
>
> Point 3: Could you review -08.txt on this topic, especially the text below.
> Given your comments, I believe I should change the last line to a MUST.
> New/   The default mode of transport is
>    secure so data models MUST clearly annotate what data nodes can be
>    passed over an insecure connection.
> /
>
> Sue
>
> ===================
> As to the normative requirements (-08.txt) version:
>
> Section 3:
>
>    I2RS allows the use of an insecure transport for portions of data
>    models that clearly indicate the use of an insecure transport.
>    Operators deploying I2RS must determine if they want to populate and
>    deploy the portions of the data model which use insecure transports.
>
> In Section 3.2 in version -08.txt
>
>    SEC-REQ-08: The I2RS protocol MUST be able to transfer data over a
>    secure transport and optionally MAY be able to transfer data over a
>    non-secure transport.  A secure transport MUST provide data
>    confidentiality, data integrity, and replay prevention.
>
>    The default I2RS transport is a secure transport.
>
>    A non-secure transport can be used for publishing telemetry data or
>    other operational state that was specifically indicated to non-
>    confidential in the data model in the Yang syntax.
>
>    The configuration of ephemeral data in the I2RS Agent by the I2RS
>    client SHOULD be done over a secure transport.  It is anticipated
>    that the passing of most I2RS ephemeral state operational status
>    SHOULD be done over a secure transport.  As
>    [I-D.ietf-i2rs-ephemeral-state] notes,  a data model MUST indicate
>    whether the transport exchanging the data between I2RS client and
>    I2RS agent is secure or insecure.
>
>    The default mode of transport is
>    secure so data models SHOULD clearly annotate what data nodes can be
>    passed over an insecure connection.
>
>>
>> Yours,
>> Joel
>>
>> -----Original Message-----
>> From: Susan Hares [mailto:[e-mail]]
>> Sent: Thursday, August 18, 2016 9:17 AM
>> To: 'Juergen Schoenwaelder' <[e-mail]>
>> Cc: [e-mail]; [e-mail]; 'Kathleen Moriarty'
>> <[e-mail]>; 'The IESG' <[e-mail]>;
>> [e-mail];
>> [e-mail]
>> Subject: RE: [i2rs] Kathleen Moriarty's Discuss on
>> draft-ietf-i2rs-protocol-security-requirements-07: (with DISCUSS and
>> COMMENT)
>>
>> Juergen and Kathleen:
>>
>> Let me proceed with two examples: BGP route views data model and the event
>> for the web-service data.
>>
>> The content of these data models are designated as exposed to public.  The
>> routing system only populates the proposed BGP route views data model with
>> the data destined for the BGP looking glass.  The policy on the routing
>> system indicates what information gets transferred.  The data model is
>> completely available to the public.  The Yang Doctors are going to review
>> this by seeing the whole model is public and available via non-secure means.
>> The security people are going to review this seeing that the whole model
>> is public, and available via an unprotect means.  The fact the data model is
>> all public should simplify the review.
>>
>> An event from the I2RS RIB that a web-service route is up is the second
>> case.  The I2RS RIB has an event based on policy that indicates a
>> web-service route is up.  The yang-1.1 doctors must review the content of
>> the event text to see it does not break privacy or provide too much
>> information   The event mechanisms will need to work over secure transport
>> and insecure transport.  Most of the data will go over the secure
>> transport event stream. However, a small amount of information may go over
>> the insecure transport stream.
>>
>> First, let me know if my use cases are understandable.  Second, let me
>> know if you disagree with this use cases.
>>
>> Fyi -  IESG approved the architecture with the insecure stream.
>>
>> Sue
>>
>> -----Original Message-----
>> From: Juergen Schoenwaelder
>> [mailto:[e-mail]]
>> Sent: Thursday, August 18, 2016 9:06 AM
>> To: Susan Hares
>> Cc: [e-mail]; [e-mail]; 'Kathleen Moriarty'; 'The
>> IESG'; [e-mail];
>> [e-mail]
>> Subject: Re: [i2rs] Kathleen Moriarty's Discuss on
>> draft-ietf-i2rs-protocol-security-requirements-07: (with DISCUSS and
>> COMMENT)
>>
>> I just do not know on which basis a data model writer can decide whether a
>> data object can be exposed in an unprotected way. How are YANG doctors going
>> to review this? How are security directorate people going to judge this? But
>> as promised, I leave (still puzzled) now.
>>
>> /js
>>
>> On Thu, Aug 18, 2016 at 09:00:14AM -0400, Susan Hares wrote:
>>> Juergen:
>>>
>>> Yes, we seem to disagree on the value of making it hardwired in the
>>> model.
>>> For me, the value is a common understanding of deployment
>>> distribution
>> such
>>> as the route-views.   Since the operators argued strongly for this point,
>> I
>>> think the best idea is to get it working in code and then see if the
>>> deployment matches the requests.
>>>
>>> Sue
>>>
>>> -----Original Message-----
>>> From: i2rs [mailto:[e-mail]] On Behalf Of Juergen
>>> Schoenwaelder
>>> Sent: Thursday, August 18, 2016 8:14 AM
>>> To: Susan Hares
>>> Cc: [e-mail]; [e-mail]; 'Kathleen Moriarty'; 'The
>>> IESG'; [e-mail];
>>> [e-mail]
>>> Subject: Re: [i2rs] Kathleen Moriarty's Discuss on
>>> draft-ietf-i2rs-protocol-security-requirements-07: (with DISCUSS and
>>> COMMENT)
>>>
>>> Sue,
>>>
>>> I still do not see why the 'mode of exposure' of data benefits from
>>> being hard-wired in the data model. For me, it is a situational and
>>> deployment specific question. But I shut up here since I aired this
>>> concern before (and we simply seem to disagree).
>>>
>>> /js
>>>
>>> On Thu, Aug 18, 2016 at 08:07:18AM -0400, Susan Hares wrote:
>>>> Juergen:
>>>>
>>>> My example is the looking glass servers for the BGP route views
>>>> project
>>>> (http://www.routeviews.org/) or a route indicating the presence of a
>>>> web-server that is public.   For the BGP I2RS route, a yang model could
>>>> replace the looking glass function, and provide events for these looking
>>>> glass functions.    For the web-server route,  an event be sent when
>> that
>>>> one route is added.
>>>>
>>>> Sue
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Juergen Schoenwaelder
>>>> [mailto:[e-mail]]
>>>> Sent: Thursday, August 18, 2016 3:32 AM
>>>> To: Susan Hares
>>>> Cc: 'Kathleen Moriarty'; 'The IESG'; [e-mail]; [e-mail];
>>>> [e-mail];
>>>> [e-mail]
>>>> Subject: Re: [i2rs] Kathleen Moriarty's Discuss on
>>>> draft-ietf-i2rs-protocol-security-requirements-07: (with DISCUSS and
>>>> COMMENT)
>>>>
>>>> On Wed, Aug 17, 2016 at 09:16:48PM -0400, Susan Hares wrote:
>>>>> ------------------------------------------------------------------
>>>>> --
>>>>> --
>>>>> COMMENT:
>>>>> ------------------------------------------------------------------
>>>>> --
>>>>> --
>>>>>
>>>>>> Section 3:
>>>>>> Can you clarify the second to last sentence?  Do you mean there
>>>>>> are
>>>> sections that indicate an insecure transport should be used?
>>>>>>  I2RS allows the use of an
>>>>>> insecure transport for portions of data models that clearly
>>>>>> indicate  insecure transport.
>>>>>
>>>>>> Perhaps:
>>>>>> I2RS allows the use of an
>>>>>> insecure transport for portions of data models that clearly
>>>>>> indicate the use of an  insecure transport.
>>>>
>>>> I still wonder how a data model writer can reasonably decide whether
>>>> a piece of information can be shipped safely over an insecure
>>>> transport since this decision often depends on the specifics of a
>>>> deployment
>>> situation.
>>>>
>>>> /js
>>>>
>>>> PS: I hope we do not end up with defining data multiple times (once
>>>>    for insecure transport and once for secured transports).
>>>>
>>>> --
>>>> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
>>>> Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
>>>> Fax:   [phone]         <http://www.jacobs-university.de/>
>>>>
>>>> _______________________________________________
>>>> i2rs mailing list
>>>> [e-mail]
>>>> https://www.ietf.org/mailman/listinfo/i2rs
>>>
>>> --
>>> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
>>> Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
>>> Fax:   [phone]         <http://www.jacobs-university.de/>
>>>
>>> _______________________________________________
>>> i2rs mailing list
>>> [e-mail]
>>> https://www.ietf.org/mailman/listinfo/i2rs
>>>
>>
>> --
>> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
>> Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
>> Fax:   [phone]         <http://www.jacobs-university.de/>
>>
>
>
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>
>
>
>



-- 

Best regards,
Kathleen