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Versions: 00 01 02                                                      
Network Working Group                                           C. Wendt
Internet-Draft                                                   Comcast
Updates: RFC3326 (if approved)                             July 12, 2021
Intended status: Standards Track
Expires: January 13, 2022


                     Identity Header Error Handling
          draft-wendt-stir-identity-header-errors-handling-02

Abstract

   This document extends STIR and the Authenticated Identity Management
   in the Session Initiation Protocol (SIP) related to error handling
   for STIR verification services and how they feedback errors to STIR
   authentication services.  Specifically, the use of a Reason header
   field and addressing scenarios that use multiple identity headers
   where some may have errors and others may not and the handling of
   those situations is defined.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on January 13, 2022.

Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must



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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Use of provisional error responses to signal errors without
       terminating the call  . . . . . . . . . . . . . . . . . . . .   3
   4.  Handling of a verification error when there is multiple
       Identity header fields  . . . . . . . . . . . . . . . . . . .   3
   5.  Handling multiple verification errors . . . . . . . . . . . .   4
   6.  Removal of the Reason header field by Authentication Service    4
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   [RFC8224] in Section 6.2.2 discusses future specifications for
   enhancement of how errors are communicated and the handling of
   multiple Identity header fields.  This specification provides some
   additional mechanisms for solutions to address these problems.

   In some deployments of STIR and specifically using SIP [RFC3261] as
   defined by [RFC8224], one issue with the current error handling,
   specifically with the use of the defined 4xx error responses, is that
   when an error occurs with the verification of the Identity header
   filed or the PASSporT contained in the Identity header field and a
   4xx response is returned, the call is then terminated.  It may be the
   case that the policy for handling errors dictates that calls should
   continue even if there is a verification error, in the case of, for
   example inadvertent errors, however the authentication service should
   still be notified of the error so that corrective action can be
   taken.  This specification will discuss the use of the Reason header
   field in subsequent provisional (1xx) responses in order to
   accomplish this.

   For the handling of multiple Identity header fields and the potential
   situation that some of the Identity header fields in a call may pass
   verification but others may have errors, this document provides a
   mechanism to add an identifier so that the authentication service can
   identify which Identity header field is being referred to in the case
   of an error.



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2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Use of provisional error responses to signal errors without
    terminating the call

   In cases where local policy dictates that a call should continue
   irregardless when any verification errors, including 4XX errors
   described in [RFC8224] Section 6.2.2, then the verification service
   SHOULD not send the 4XX as a response, but rather include the error
   response code and reason phrase in a Reason header field, defined in
   [RFC3326], in the next provisional or final responses sent to the
   authentication service.

   Example Reason header field:

   Reason: SIP ;cause=436 ;text="Bad Identity Info"

4.  Handling of a verification error when there is multiple Identity
    header fields

   In cases where a SIP message includes multiple Identity header fields
   and one of those Identity header fields has an error, the
   verification service SHOULD include the error response code and
   reason phrase associated with the error in a Reason header field,
   defined in [RFC3326], in the next provisional or final responses sent
   to the authentication service.  The reason cause in the Reason header
   field SHOULD represent the error that occurred when verifying the
   contents of the Identity header field.  The association of a Reason
   header field and error to a specific Identity header field is
   accomplished by adding a "ppt" parameter containing the PASSporT that
   generated the error to the Reason header field.  The "ppt" parameter
   for the Reason header field is optional, but RECOMMENDED, in
   particular for cases that a SIP INVITE contains multiple Identity
   header fields.  The PASSporT can be included in full form, or
   optionally in compact form, where only the signature of the PASSporT
   is used to identify the reported Identity header field with an error.

   Example Reason header field with full form PASSporT:







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   Reason: SIP ;cause=436 ;text="Bad Identity Info" ;ppt= \
   "eyJhbGciOiJFUzI1NiIsInR5cCI6InBhc3Nwb3J0IiwieDV1I \
   joiaHR0cHM6Ly9jZXJ0LmV4YW1wbGUub3JnL3Bhc3Nwb3J0LmNlciJ9.eyJ \
   kZXN0Ijp7InVyaSI6WyJzaXA6YWxpY2VAZXhhbXBsZS5jb20iXX0sImlhdC \
   I6IjE0NDMyMDgzNDUiLCJvcmlnIjp7InRuIjoiMTIxNTU1NTEyMTIifX0.r \
   q3pjT1hoRwakEGjHCnWSwUnshd0-zJ6F1VOgFWSjHBr8Qjpjlk-cpFYpFYs \
   ojNCpTzO3QfPOlckGaS6hEck7w"

   Example Reason header field with compact form PASSporT: ~~~~~~~~~~~
   Reason: SIP ;cause=436 ;text="Bad Identity Info" ;ppt= \
   "..rq3pjT1akEGjHCnWSwUnshd0-zJ6F1VOgFWSjHBr8Qjpjlk-cpFYpFYs \
   ojNCpTzO3QfPOlckGaS6hEck7w" ~~~~~~~~~~~

5.  Handling multiple verification errors

   This specification updates [RFC3326] in that for STIR applications
   the use of multiple Reason header fields with the same "SIP" protocol
   string is allowed.  So, if there is multiple Identity header field
   verification errors being reported the verification service SHOULD
   include corresponding Reason header fields with "ppt" parameters
   including full or compact form of the PASSporT with cause and text
   parameters identifying each error.

   Example Reason header fields for two identity info errors:

   Reason: SIP ;cause=436 ;text="Bad Identity Info" ;ppt= \
   "eyJhbGciOiJFUzI1NiIsInR5cCI6InBhc3Nwb3J0IiwieDV1I \
   joiaHR0cHM6Ly9jZXJ0LmV4YW1wbGUub3JnL3Bhc3Nwb3J0LmNlciJ9.eyJ \
   kZXN0Ijp7InVyaSI6WyJzaXA6YWxpY2VAZXhhbXBsZS5jb20iXX0sImlhdC \
   I6IjE0NDMyMDgzNDUiLCJvcmlnIjp7InRuIjoiMTIxNTU1NTEyMTIifX0.r \
   q3pjT1hoRwakEGjHCnWSwUnshd0-zJ6F1VOgFWSjHBr8Qjpjlk-cpFYpFYs \
   ojNCpTzO3QfPOlckGaS6hEck7w"

   Reason: SIP ;cause=436 ; text="Bad Identity Info" ;ppt= \
   "eyJhbGciOiJFUzI1NiIsInR5cCI6InBhc3Nwb3J0IiwieDV1I \
   joiaHR0cHM6Ly9jZXJ0LmV4YW1wbGUub3JnL3Bhc3Nwb3J0LmNlciJ9.eyJ \
   xpY2VAZXhhbXBsZS5jb20iXX0sImlhdCkZXN0Ijp7InVyaSI6WyJzaXA6YW \
   p7InRuIjoiMTIxNTU1NTEyMTIifX0I6IjE0NDMyMDgzNDUiLCJvcmlnIj.r \
   J6F1VOgFWSjHBr8Qjpjlk-cpFYpFYsq3pjT1hoRwakEGjHCnWSwUnshd0-z \
   ckGaS6hEck7wojNCpTzO3QfPOl"


6.  Removal of the Reason header field by Authentication Service

   When an Authentication Service [RFC8224] receives the Reason header
   field with a PASSporT it generated as part of an Identity header
   field and the authentication of a call, it should first follow local
   policy to recognize and acknowledge the error (e.g. perform



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   operational actions like logging or alarming), but then MUST remove
   the identified Reason header field to avoid the PASSporT information
   going upstream to UAC or UAS that may not be authorized to see claim
   information contained in the PASSporT for privacy or other reasons.

7.  Acknowledgements

   Would like to thank David Hancock for help to identify these error
   scenarios and Jon Peterson, Roman Shpount, and STIR working group for
   helpful feedback and discussion.

8.  Security Considerations

   TBD

9.  References

9.1.  Normative References

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              DOI 10.17487/RFC3261, June 2002,
              <https://www.rfc-editor.org/info/rfc3261>.

   [RFC3326]  Schulzrinne, H., Oran, D., and G. Camarillo, "The Reason
              Header Field for the Session Initiation Protocol (SIP)",
              RFC 3326, DOI 10.17487/RFC3326, December 2002,
              <https://www.rfc-editor.org/info/rfc3326>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8224]  Peterson, J., Jennings, C., Rescorla, E., and C. Wendt,
              "Authenticated Identity Management in the Session
              Initiation Protocol (SIP)", RFC 8224,
              DOI 10.17487/RFC8224, February 2018,
              <https://www.rfc-editor.org/info/rfc8224>.

9.2.  Informative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.





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Author's Address

   Chris Wendt
   Comcast
   Comcast Technology Center
   Philadelphia, PA  19103
   USA

   Email: chris-ietf@chriswendt.net










































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