draft-ietf-stir-rph-emergency-services-02.txt   draft-ietf-stir-rph-emergency-services-03.txt 
STIR M. Dolly STIR M. Dolly
Internet-Draft AT&T Internet-Draft AT&T
Intended status: Standards Track C. Wendt Intended status: Standards Track C. Wendt
Expires: January 14, 2021 Comcast Expires: April 9, 2021 Comcast
July 13, 2020 October 06, 2020
Assertion Values for a Resource Priority Header Claim and a SIP Priority Assertion Values for a Resource Priority Header Claim and a SIP Priority
Header Claim in Support of Emergency Services Networks Header Claim in Support of Emergency Services Networks
draft-ietf-stir-rph-emergency-services-02 draft-ietf-stir-rph-emergency-services-03
Abstract Abstract
This document adds new assertion values for a Resource Priority This document adds new assertion values for a Resource Priority
Header ("rph") claim and a new SIP Priority Header claim ("sph") for Header ("rph") claim and a new SIP Priority Header claim ("sph") for
protection of the "psap-callback" value as part of the "rph" PASSporT protection of the "psap-callback" value as part of the "rph" PASSporT
extension, in support of the security of Emergency Services Networks extension, in support of the security of Emergency Services Networks
for emergency call origination and callback. for emergency call origination and callback.
Status of This Memo Status of This Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 14, 2021. This Internet-Draft will expire on April 9, 2021.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. New Assertion Values for "rph" claim . . . . . . . . . . . . 3 3. New Assertion Values for "rph" claim . . . . . . . . . . . . 3
3.1. ESorig . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. EScallback . . . . . . . . . . . . . . . . . . . . . . . 4
4. The SIP Priority header "sph" claim . . . . . . . . . . . . . 4 4. The SIP Priority header "sph" claim . . . . . . . . . . . . . 4
5. Order of Claim Keys . . . . . . . . . . . . . . . . . . . . . 5 5. Order of Claim Keys . . . . . . . . . . . . . . . . . . . . . 5
6. Compact Form of PASSporT . . . . . . . . . . . . . . . . . . 5 6. Compact Form of PASSporT . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7.1. PASSporT Resource Priority Header (rph) Types . . . . . . 5 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7.2. JSON Web Token claims . . . . . . . . . . . . . . . . . . 6 8.1. JSON Web Token claims . . . . . . . . . . . . . . . . . . 6
8. Security Considerations . . . . . . . . . . . . . . . . . . . 6 9. Security Considerations . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . 6 10.1. Normative References . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . 7 10.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
Personal Assertion Token (PASSporT) Extension for Resource Priority Personal Assertion Token (PASSporT) Extension for Resource Priority
Authorization [RFC8443] extended the Personal Assertion Token Authorization [RFC8443] extended the Personal Assertion Token
(PASSporT) specification defined in [RFC8225] to allow the inclusion (PASSporT) specification defined in [RFC8225] to allow the inclusion
of cryptographically signed assertions of authorization for the of cryptographically signed assertions of authorization for the
values populated in the Session Initiation Protocol (SIP) "Resource- values populated in the Session Initiation Protocol (SIP) "Resource-
Priority" header field [RFC4412], which is used for communications Priority" header field [RFC4412]. [I-D.rosen-stir-emergency-calls]
resource prioritization and the SIP "Priority" header field, used for introduces the need and justification for the protection of both the
categorizing the priority use of the call. SIP "Resource-Priority" and "Priority" header fields, used for
categorizing the priority use of the call in the telephone network,
specifically for emergency calls.
Compromise of the SIP "Resource-Priority" header field could lead to Compromise of the SIP "Resource-Priority" or "Priority" header fields
misuse of network resources (i.e., during congestion scenarios), could lead to misuse of network resources (i.e., during congestion
impacting the application services supported using the SIP "Resource- scenarios), impacting the application services supported using the
Priority" header field. SIP "Resource-Priority" header field and the handling of Public
Saftey Answering Point (PSAP) callbacks.
[RFC8225] allows extensions by which an authority on the originating [RFC8225] allows extensions by which an authority on the originating
side verifying the authorization of a particular communication for side verifying the authorization of a particular communication for
the SIP "Resource-Priority" header field or the SIP "Priority" header the SIP "Resource-Priority" header field or the SIP "Priority" header
field can use PASSPorT claims to cryptographically sign the field can use PASSPorT claims to cryptographically sign the
information associated with either the SIP "Resource-Priority" or information associated with either the SIP "Resource-Priority" or
"Priority" header fields and convey assertion of those values by the "Priority" header field and convey assertion of those values by the
signing party authorization. A signed SIP "Resource-Priority" or signing party authorization. A signed SIP "Resource-Priority" or
"Priority" header fields will allow a receiving entity (including "Priority" header field will allow a receiving entity (including
entities located in different network domains/boundaries) to verify entities located in different network domains/boundaries) to verify
the validity of assertions to act on the information with confidence the validity of assertions to act on the information with confidence
that the information has not been spoofed or compromised. that the information has not been spoofed or compromised.
This document adds new assertion values for a Resource Priority This document adds new "auth" array key values for a Resource
Header ("rph") claim defined in [RFC8443], in support of Emergency Priority Header ("rph") claim defined in [RFC8443], in support of
Services Networks for emergency call origination and callback. This Emergency Services Networks for emergency call origination and
document also defines a new claim, "sph", including protection of the callback. This document additionally defines a new PASSporT claim,
SIP Priority header for the indication of an emergency service call- "sph", including protection of the SIP Priority header for the
back assigned the value "psap-callback" as defined in [RFC7090]. The indication of an emergency service call-back assigned the value
use of these new assertion values for real-time communications "psap-callback" as defined in [RFC7090]. The use of the newly
supported using the SIP 'Resource-Priority' and 'Priority' header defined claim and key values corresponding to the SIP 'Resource-
fields for emergency services is introduced in Priority' and 'Priority' header fields for emergency services is
[I-D.rosen-stir-emergency-calls] but otherwise out-of-scope of this introduced in [I-D.rosen-stir-emergency-calls] but otherwise out-of-
document. In addition, the PASSPorT claims and values defined in scope of this document. In addition, the PASSPorT claims and values
this document are intended for use in environments where there are defined in this document are intended for use in environments where
means to verify that the signer of the SIP 'Resource-Priority' and there are means to verify that the signer of the SIP 'Resource-
'Priority' header fields is authoritative. Priority' and 'Priority' header fields is authoritative.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. New Assertion Values for "rph" claim 3. New Assertion Values for "rph" claim
This specification defines new assertions values for: This specification defines the ability to sign the SIP Resource-
Priority Header field namespace for local emergency communications
* "ESorig": Emergency Services call origination defined in [RFC7135] and represented by the string "esnet.x" where x
* "EScallback": Emergency Services callback. is the priority-level allowed in the esnet namespace. As of the
writing of this specification the priority-level is between 0 and 4,
but may be extended by future specifications.
3.1. ESorig Similar to the values allowed by [RFC8443] for the "auth" JSON object
key inside the "rph" claim, the string "esnet.x" with the appropriate
value should be used when resource priority is required for local
emergency communications corresponding and exactly matching the SIP
Resource-Priority header string representing the namespace invoked in
the call.
When using "ESorig" as the "rph" assertion value, the "orig" claim of When using "esnet.x" as the "auth" assertion value in emergency
the PASSporT MUST represent the calling party number that initiates service destined calls, the "orig" claim of the PASSporT MUST
the call to emergency services. The "dest" claim MUST either be a represent the calling party number that initiates the call to
country or region specific dial string (e.g., "911" for North America emergency services. The "dest" claim MUST either be a country or
or "112" GSM defined string used in Europe and other countries) or region specific dial string (e.g., "911" for North America or "112"
"urn:service:sos" as defined in TBD, representing the emergency GSM defined string used in Europe and other countries) or
"urn:service:sos" as defined in [RFC5031], representing the emergency
services destination of the call. services destination of the call.
The following is an example of an "rph" claim for SIP 'Resource- The following is an example of an "rph" claim for SIP 'Resource-
Priority' header field with a "ESorig" assertion: Priority' header field with an "esnet.1" assertion:
{ {
"orig":{"tn":"12155551212"}, "orig":{"tn":"12155551212"},
"dest":{["uri":"urn:service:sos"]}, "dest":{["uri":"urn:service:sos"]},
"iat":1443208345, "iat":1443208345,
"rph":{"ESorig":["esnet,x"]} "rph":{"auth":["esnet.1"]}
} }
3.2. EScallback For emergency services callbacks, the "orig" claim of the "rph"
PASSporT MUST represent the Public Saftey Answering Point (PSAP)
When using "EScallback" as the "rph" assertion value, the "orig" telephone number. The "dest" claim MUST be the telephone number
claim of the PASSporT MUST represent the emergency network telephone representing the original calling party of the emergency service call
number. The "dest" claim MUST be the telephone number representing that is being called back.
the original calling party of the emergency service call that is
being called back.
The following is an example of an "rph" claim for SIP 'Resource- The following is an example of an "rph" claim for SIP 'Resource-
Priority' header field with a "EScallback" assertion: Priority' header field with a "esnet.0" assertion:
{ {
"orig":{"tn":"12155551213"}, "orig":{"tn":"12155551213"},
"dest":{["tn":"12155551212"]}, "dest":{["tn":"12155551212"]},
"iat":1443208345, "iat":1443208345,
"rph":{"EScallback":["esnet,x"]} "rph":{"auth":["esnet.0"]}
} }
After the header and claims PASSporT objects have been constructed, After the header and claims PASSporT objects have been constructed,
their signature is generated normally per the guidance in [RFC8225] their signature is generated normally per the guidance in [RFC8225]
using the full form of PASSPorT. The credentials (i.e., Certificate) using the full form of PASSPorT. The credentials (i.e., Certificate)
used to create the signature must have authority over the namespace used to create the signature must have authority over the namespace
of the "rph" claim, and there is only one authority per claim. The of the "rph" claim, and there is only one authority per claim. The
authority MUST use its credentials associated with the specific authority MUST use its credentials associated with the specific
service supported by the resource priority namespace in the claim. service supported by the resource priority namespace in the claim.
If r-values are added or dropped by the intermediaries along the If r-values are added or dropped by the intermediaries along the
path, the intermediaries must generate a new "rph" header and sign path, the intermediaries must generate a new "rph" header and sign
the claim with their own authority. the claim with their own authority.
4. The SIP Priority header "sph" claim 4. The SIP Priority header "sph" claim
As discussed in [I-D.rosen-stir-emergency-calls], and as defined in As defined in [RFC7090] the SIP Priority header may be set to the
[RFC7090] the SIP Priority header may be set to the value "psap- value "psap-callback" for emergency services callback calls. Because
callback" for emergency services callback calls. Because some SIP some SIP networks may act on this value and provide priority or other
networks may act on this value and provide priority or other special special routing based on this value, it is important to protect and
routing based on this value, it is important to protect and validate validate the authoritative use associated with it.
the authoritative use associated with it.
Therefore, we define a new claim key as part of the "rph" PASSporT, Therefore, we define a new claim key as part of the "rph" PASSporT,
"sph", which MUST be used only for authorized emergency callbacks and "sph", which MUST be used only for authorized emergency callbacks and
correspond to a SIP Priority header with the value "psap-callback". correspond to a SIP Priority header with the value "psap-callback".
The value of the "sph" claim key should only be "psap-callback" to The value of the "sph" claim key should only be "psap-callback" to
match the SIP Priority header field value for authorized emergency match the SIP Priority header field value for authorized emergency
services callbacks. services callbacks.
The following is an example of an "sph" claim for SIP 'Priority' The following is an example of an "sph" claim for SIP 'Priority'
header field with the value "psap-callback": header field with the value "psap-callback":
{ {
"orig":{"tn":"12155551213"}, "orig":{"tn":"12155551213"},
"dest":{["tn":"12155551212"]}, "dest":{["tn":"12155551212"]},
"iat":1443208345, "iat":1443208345,
"rph":{"EScallback":["esnet,x"]}, "rph":{"auth":["esnet.0"]},
"sph":"psap-callback" "sph":"psap-callback"
} }
5. Order of Claim Keys 5. Order of Claim Keys
The order of the claim keys MUST follow the rules of [RFC8225] The order of the claim keys MUST follow the rules of [RFC8225]
Section 9; the claim keys MUST appear in lexicographic order. Section 9; the claim keys MUST appear in lexicographic order.
Therefore, the claim keys discussed in this document appear in the Therefore, the claim keys discussed in this document appear in the
PASSporT Payload in the following order, PASSporT Payload in the following order,
skipping to change at page 5, line 42 skipping to change at page 5, line 46
o rph o rph
o sph o sph
6. Compact Form of PASSporT 6. Compact Form of PASSporT
The use of the compact form of PASSporT is not specified in this The use of the compact form of PASSporT is not specified in this
document or recommended for 'rph' PASSporTs. document or recommended for 'rph' PASSporTs.
7. IANA Considerations 7. Acknowledgements
7.1. PASSporT Resource Priority Header (rph) Types
This specification requests that the IANA add two new assertion
values to the "PASSporT Resource Priority Header (rph) Types"
Registry as defined in [RFC8443].
The following assertion values will be added to the registry:
* "ESorig": Emergency Services call origination The authors would like to thank Brian Rosen, Terry Reese, and Jon
* "EScallback": Emergency Services callback Peterson for helpful suggestions, comments, and corrections.
+--------------+------------+ 8. IANA Considerations
| rph Type | Reference |
+--------------+------------+
| ESorig | [this RFC] |
+--------------+------------+
| EScallback | [this RFC] |
+--------------+------------+
7.2. JSON Web Token claims 8.1. JSON Web Token claims
This specification requests that the IANA add two new claims to the This specification requests that the IANA add one new claim to the
JSON Web Token Claims registry as defined in [RFC7519]. JSON Web Token Claims registry as defined in [RFC7519].
Claim Name: "sph" Claim Name: "sph"
Claim Description: SIP Priority header field Claim Description: SIP Priority header field
Change Controller: IESG Change Controller: IESG
Specification Document(s): [RFCThis] Specification Document(s): [RFCThis]
8. Security Considerations 9. Security Considerations
The security considerations discussed in [RFC8224], Section 12, are The security considerations discussed in [RFC8224], Section 12, are
applicable here. applicable here.
9. References 10. References
9.1. Normative References 10.1. Normative References
[I-D.rosen-stir-emergency-calls] [I-D.rosen-stir-emergency-calls]
Rosen, B., "Non-Interactive Emergency Calls", draft-rosen- Rosen, B., "Non-Interactive Emergency Calls", draft-rosen-
stir-emergency-calls-00 (work in progress), March 2020. stir-emergency-calls-00 (work in progress), March 2020.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002, DOI 10.17487/RFC3261, June 2002,
<https://www.rfc-editor.org/info/rfc3261>. <https://www.rfc-editor.org/info/rfc3261>.
[RFC4412] Schulzrinne, H. and J. Polk, "Communications Resource [RFC4412] Schulzrinne, H. and J. Polk, "Communications Resource
Priority for the Session Initiation Protocol (SIP)", Priority for the Session Initiation Protocol (SIP)",
RFC 4412, DOI 10.17487/RFC4412, February 2006, RFC 4412, DOI 10.17487/RFC4412, February 2006,
<https://www.rfc-editor.org/info/rfc4412>. <https://www.rfc-editor.org/info/rfc4412>.
[RFC5031] Schulzrinne, H., "A Uniform Resource Name (URN) for
Emergency and Other Well-Known Services", RFC 5031,
DOI 10.17487/RFC5031, January 2008,
<https://www.rfc-editor.org/info/rfc5031>.
[RFC7090] Schulzrinne, H., Tschofenig, H., Holmberg, C., and M. [RFC7090] Schulzrinne, H., Tschofenig, H., Holmberg, C., and M.
Patel, "Public Safety Answering Point (PSAP) Callback", Patel, "Public Safety Answering Point (PSAP) Callback",
RFC 7090, DOI 10.17487/RFC7090, April 2014, RFC 7090, DOI 10.17487/RFC7090, April 2014,
<https://www.rfc-editor.org/info/rfc7090>. <https://www.rfc-editor.org/info/rfc7090>.
[RFC7135] Polk, J., "Registering a SIP Resource Priority Header
Field Namespace for Local Emergency Communications",
RFC 7135, DOI 10.17487/RFC7135, May 2014,
<https://www.rfc-editor.org/info/rfc7135>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token [RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>. <https://www.rfc-editor.org/info/rfc7519>.
[RFC8224] Peterson, J., Jennings, C., Rescorla, E., and C. Wendt, [RFC8224] Peterson, J., Jennings, C., Rescorla, E., and C. Wendt,
"Authenticated Identity Management in the Session "Authenticated Identity Management in the Session
Initiation Protocol (SIP)", RFC 8224, Initiation Protocol (SIP)", RFC 8224,
DOI 10.17487/RFC8224, February 2018, DOI 10.17487/RFC8224, February 2018,
<https://www.rfc-editor.org/info/rfc8224>. <https://www.rfc-editor.org/info/rfc8224>.
skipping to change at page 7, line 34 skipping to change at page 7, line 34
[RFC8226] Peterson, J. and S. Turner, "Secure Telephone Identity [RFC8226] Peterson, J. and S. Turner, "Secure Telephone Identity
Credentials: Certificates", RFC 8226, Credentials: Certificates", RFC 8226,
DOI 10.17487/RFC8226, February 2018, DOI 10.17487/RFC8226, February 2018,
<https://www.rfc-editor.org/info/rfc8226>. <https://www.rfc-editor.org/info/rfc8226>.
[RFC8443] Singh, R., Dolly, M., Das, S., and A. Nguyen, "Personal [RFC8443] Singh, R., Dolly, M., Das, S., and A. Nguyen, "Personal
Assertion Token (PASSporT) Extension for Resource Priority Assertion Token (PASSporT) Extension for Resource Priority
Authorization", RFC 8443, DOI 10.17487/RFC8443, August Authorization", RFC 8443, DOI 10.17487/RFC8443, August
2018, <https://www.rfc-editor.org/info/rfc8443>. 2018, <https://www.rfc-editor.org/info/rfc8443>.
9.2. Informative References 10.2. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC7340] Peterson, J., Schulzrinne, H., and H. Tschofenig, "Secure [RFC7340] Peterson, J., Schulzrinne, H., and H. Tschofenig, "Secure
Telephone Identity Problem Statement and Requirements", Telephone Identity Problem Statement and Requirements",
RFC 7340, DOI 10.17487/RFC7340, September 2014, RFC 7340, DOI 10.17487/RFC7340, September 2014,
<https://www.rfc-editor.org/info/rfc7340>. <https://www.rfc-editor.org/info/rfc7340>.
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