Hi Alexey, Thanks for your comments, see inline...
> -----Original Message----- > From: Pce [mailto:pce-boun...@ietf.org] On Behalf Of Alexey Melnikov > Sent: 03 August 2017 15:35 > To: The IESG <i...@ietf.org> > Cc: cmarga...@juniper.net; draft-ietf-pce-pc...@ietf.org; pce@ietf.org; > pce-cha...@ietf.org > Subject: [Pce] Alexey Melnikov's Discuss on draft-ietf-pce-pceps-15: (with > DISCUSS and COMMENT) > > Alexey Melnikov has entered the following ballot position for > draft-ietf-pce-pceps-15: 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-pce-pceps/ > > > > ---------------------------------------------------------------------- > DISCUSS: > ---------------------------------------------------------------------- > > I am very glad to see this document and I will be switching to "Yes" once > we discuss the following issues: > > 1) > +-+-+ +-+-+ > |PCC| |PCE| > +-+-+ +-+-+ > | | > | StartTLS | > | msg | > |------- | > | \ StartTLS | > | \ msg | > | \ ---------| > | \/ | > | /\ | > | / -------->| > | / | > |<------ | > |:::::::::TLS:::::::::| TLS Establishment > |:::::Establishment:::| Failure > | | > |<--------------------| Send Error-Type TBA2 > | PCErr | Error-Value 3/4 > | | > > Figure 2: Both PCEP Speaker supports PCEPS (strict), but cannot > establish TLS > > Firstly, I think you also need to demonstrate a case when the server end > of TLS is refusing to startTLS before trying TLS negotiation (e.g. if it > doesn't have certificate configured). In this case you need to send PCErr > in the clear. I think earlier text suggest that this case is possible. > [[Dhruv Dhody]] No, the only error to StartTLS is by an implementation that does not understand the message. In case certificate is not configured we would start TLS negotiation, which would fail. > Secondly, does the case depicted on this picture mean that TLS was > negotiated successfully, but TLS identities were not successfully verified? > (I.e. the PCErr is sent over the TLS layer). If TLS failed to negotiate, > you don't have a channel to send data on, as the other end will get > confused. I think you just have to close connection in such case. > [[Dhruv Dhody]] No, the PCErr is sent in clear over the TCP connection (underlying transport). EKR also made a similar point. I updated the text to include this - Note that, the PCEP implementation MUST send the PCErr message once the TLS connection has been closed i.e. the TLS close_notify [RFC5246] has been received from the peer. As per [RFC5246], if the data may be carried over the underlying transport after the TLS connection is closed, the TLS implementation must receive the responding close_notify alert before indicating to the application layer that the TLS connection has ended. > So maybe you need 3 figures describing the above 3 cases. > > 2) In Section 3.4: > > + Implementations MAY allow the configuration of a set of > additional properties of the certificate to check for a > peer's authorization to communicate (e.g., a set of allowed > values in subjectAltName:URI or a set of allowed X509v3 > Certificate Policies) > > Can you give an example of what you expect to see in the > subjectAltName:URI? > Your current text doesn't seem sufficient for interoperability. > [[Dhruv Dhody]] The reference for the text was from RFC6614, with the aim to keep the door open to define application service type portion to be checked as part of URI. I have added text that the definition of these properties is out of scope of this document. > ---------------------------------------------------------------------- > COMMENT: > ---------------------------------------------------------------------- > > I am agreeing with Ekr's DISCUSS points. Some of mine might be just a > different phrasing of his. > > In Section 3.4. TLS Connection Establishment > > * PCEPS implementations MUST, at a minimum, support negotiation > of the TLS_RSA_WITH_AES_128_GCM_SHA256, and SHOULD support > TLS_RSA_WITH_AES_256_GCM_SHA384 as well [RFC5288]. In > addition, PCEPS implementations MUST support negotiation of > the mandatory-to-implement ciphersuites required by the > versions of TLS that they support. > > Should the last sentence apply starting from TLS 1.3 forward? > [[Dhruv Dhody]] Ack. Updated. > In Section 3.5: > > [I-D.ietf-pce-stateful-sync-optimizations] specify a Speaker Entity > Identifier TLV (SPEAKER-ENTITY-ID), as an optional TLV that MAY be > included in the OPEN Object. It contains a unique identifier for the > node that does not change during the lifetime of the PCEP speaker. > An implementation would thus expose the speaker entity identifier as > part of the X509v3 certificate, so that an implementation could use > > Can you be a bit more specific, as this looks underspecified. Are you > thinking about using subject name or subject alt name for this (or either)? > [[Dhruv Dhody]]This has been updated to use subjectAltName:otherName. > this identifier for the peer identification trust model. > > In the Security Considerations sections: > > I think you should also talk about downgrade attacks here, e.g. > man-in-the-middle injecting error response in response to StartTLS command > or man-in-the-middle stripping StartTLS command. > > [[Dhruv Dhody]] Updated to include - PCEPS implementations that continue to accept connections without TLS are susceptible to downgrade attacks as described in [RFC7457]. An attacker could attempt to remove the use of StartTLS message that request the use of TLS as it pass on the wire in clear, and further inject a PCErr message that suggest to attempt PCEP connection without TLS. Regards, Dhruv > _______________________________________________ > Pce mailing list > Pce@ietf.org > https://www.ietf.org/mailman/listinfo/pce _______________________________________________ Pce mailing list Pce@ietf.org https://www.ietf.org/mailman/listinfo/pce
