Internet DRAFT - draft-ietf-secevent-delivery
draft-ietf-secevent-delivery
Network Working Group P. Hunt, Ed.
Internet-Draft Oracle
Intended status: Standards Track M. Scurtescu
Expires: September 5, 2018 Google
M. Ansari
Cisco
A. Nadalin
Microsoft
A. Backman
Amazon
March 4, 2018
SET Token Delivery Using HTTP
draft-ietf-secevent-delivery-02
Abstract
This specification defines how a series of security event tokens
(SETs) may be delivered to a previously registered receiver using
HTTP POST over TLS initiated as a push to the receiver, or as a poll
by the receiver. The specification also defines how delivery can be
assured subject to the SET Token Receiver's need for assurance.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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 September 5, 2018.
Copyright Notice
Copyright (c) 2018 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
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(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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described in the Simplified BSD License.
Table of Contents
1. Introduction and Overview . . . . . . . . . . . . . . . . . . 2
1.1. Notational Conventions . . . . . . . . . . . . . . . . . 3
1.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . 3
2. SET Event Stream Protocol . . . . . . . . . . . . . . . . . . 4
2.1. Event Delivery Process . . . . . . . . . . . . . . . . . 4
2.2. Push Delivery using HTTP . . . . . . . . . . . . . . . . 6
2.3. Polling Delivery using HTTP . . . . . . . . . . . . . . . 8
2.3.1. Polling HTTP Request Attributes . . . . . . . . . . . 8
2.3.2. Polling HTTP Response Attributes . . . . . . . . . . 10
2.3.3. Poll Request . . . . . . . . . . . . . . . . . . . . 10
2.3.4. Poll Response . . . . . . . . . . . . . . . . . . . . 14
2.4. Error Response Handling . . . . . . . . . . . . . . . . . 16
3. Authentication and Authorization . . . . . . . . . . . . . . 17
3.1. Use of Tokens as Authorizations . . . . . . . . . . . . . 18
4. Security Considerations . . . . . . . . . . . . . . . . . . . 18
4.1. Authentication Using Signed SETs . . . . . . . . . . . . 18
4.2. HTTP Considerations . . . . . . . . . . . . . . . . . . . 19
4.3. TLS Support Considerations . . . . . . . . . . . . . . . 19
4.4. Authorization Token Considerations . . . . . . . . . . . 19
4.4.1. Bearer Token Considerations . . . . . . . . . . . . . 19
5. Privacy Considerations . . . . . . . . . . . . . . . . . . . 20
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
7.1. Normative References . . . . . . . . . . . . . . . . . . 20
7.2. Informative References . . . . . . . . . . . . . . . . . 22
Appendix A. Other Streaming Specifications . . . . . . . . . . . 23
Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 24
Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction and Overview
This specification defines how a stream of SETs (see
[I-D.ietf-secevent-token]) can be transmitted to a previously
registered Event Receiver using HTTP [RFC7231] over TLS. The
specification defines a method to push SETs via HTTP POST and another
method to poll for SETs using HTTP POST.
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This specification defines two methods of SET delivery in what is
known as Event Streams.
This specification does not define the method by which Event Streams
are defined, provisioned, managed, monitored, and configured and is
out of scope of this specification.
[[This work is TBD by the SECEVENTS WG]]
1.1. Notational Conventions
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.
For purposes of readability examples are not URL encoded.
Implementers MUST percent encode URLs as described in Section 2.1 of
[RFC3986] .
Throughout this documents all figures MAY contain spaces and extra
line-wrapping for readability and space limitations. Similarly, some
URI's contained within examples, have been shortened for space and
readability reasons.
1.2. Definitions
This specification assumes terminology defined in the Security Event
Token specification[I-D.ietf-secevent-token] .
The following definitions are defined for Security Event
distribution:
Event Transmitter
A service provider that delivers SETs to other providers known as
Event Receivers. An Event Transmitter is responsible for offering
a service that allows the Event Receiver to check the Event Stream
configuration and status known as the "Control Plane".
Event Receiver
A service provider that registers to receive SETs from an Event
Transmitter and provides an endpoint to receive SETs via HTTP
POST. Event Receivers can check current Event Stream
configuration and status by accessing the Event Transmitters
"Control Plane".
Event Stream
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An Event Stream is a defined location, distribution method and
whereby an Event Transmitter and Event Receiver exchange a pre-
defined family of SETs. A Stream is assumed to have configuration
data such as HTTP endpoints, timeouts, public key sets for signing
and encryption, and Event Families.
Subject
The security subject around which a security event has occurred.
For example, a security subject might per a user, a person, an
email address, a service provider entity, an IP address, an OAuth
Client, a mobile device, or any identifiable thing referenced in
security and authorization systems.
Event
An Event is defined to be an event as represented by a security
event token (SET). See [I-D.ietf-secevent-token].
NumericDate
A JSON numeric value representing the number of seconds from
1970-01-01T00:00:00Z UTC until the specified UTC date/time,
ignoring leap seconds. This is equivalent to the IEEE Std 1003.1,
2013 Edition [POSIX.1] definition "Seconds Since the Epoch", in
which each day is accounted for by exactly 86400 seconds, other
than that non-integer values can be represented. See [RFC3339]
for details regarding date/times in general and UTC in particular.
2. SET Event Stream Protocol
An Event Stream represents the communication channel over which a
series of SETs are delivered to a configured Event Receiver.
2.1. Event Delivery Process
When an Event occurs, the Event Transmitter constructs a SET token
[I-D.ietf-secevent-token] that describes the Event. The Event
Transmitter determines the Event Streams over which the SET should be
distributed to.
How SETs are defined and the process by which Events are identified
for Event Receivers is out-of-scope of this specification.
When a SET is available for an Event Receiver, the Event Transmitter
attempts to deliver the SET based on the Event Receiver's registered
delivery mechanism:
o The Event Transmitter uses an HTTP/1.1 POST to the Event Receiver
endpoint to deliver the SET;
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o The Event Transmitter queues up the SET in a buffer so that an
Event Receiver MAY poll for SETs using HTTP/1.1 POST.
o Or, the Event Transmitter delivers the Event through a different
method not defined by this specification.
Delivery of SETs MAY be delivered using one of two modes:
PUSH
In which SETs are delivered one at a time using HTTP POST requests
by an Event Transmitter to an Event Receiver. The HTTP request
body is a JSON Web Token [RFC7519] with a "Content-Type" header of
"application/secevent+jwt" as defined in Section 2.2 and 6.2 of
[I-D.ietf-secevent-token]. Upon receipt, the Event Receiver
acknowledges receipt with a response with HTTP Status 202, as
described below in Section 2.2.
POLLING Where multiple SETs are delivered in a JSON document
[RFC7159] to an Event Receiver in response to an HTTP POST request
to the Event Transmitter. Then in a following request, the Event
Receiver acknowledges received SETs and MAY poll for more. In
POLLING mode, all requests and responses are JSON documents and
use a "Content-Type" of "application/json" as described in
Section 2.3.
After successful (acknowledged) SET delivery, Event Transmitters
SHOULD NOT be required to maintain or record SETs for recovery. Once
a SET is acknowledged, the Event Receiver SHALL be responsible for
retention and recovery.
Transmitted SETs SHOULD be self-validating (e.g. signed) if there is
a requirement to verify they were issued by the Event Transmitter at
a later date when de-coupled from the original delivery where
authenticity could be checked via the HTTP or TLS mutual
authentication.
Upon receiving a SET, the Event Receiver reads the SET and validates
it. The Event Receiver MUST acknowledge receipt to the Event
Transmitter, using the defined acknowledgement or error method
depending on the method of transfer.
The Event Receiver SHALL NOT use the Event acknowledgement mechanism
to report Event errors other than relating to the parsing and
validation of the SET.
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2.2. Push Delivery using HTTP
This method allows an Event Transmitter to use HTTP POST
(Section 4.3.3 [RFC7231]) to deliver SETs to a previously registered
web callback URI supplied by the Event Receiver as part of an Event
Stream configuration process (not defined by this document).
The SET to be delivered MAY be signed and/or encrypted as defined in
[I-D.ietf-secevent-token].
The Event Stream configuration defines a URI of an Event Receiver
provided endpoint which accepts HTTP POST requests (e.g.
"https://rp.example.com/Events").
The HTTP Content-Type (see Section 3.1.1.5 [RFC7231]) for the HTTP
POST is "application/secevent+jwt" and SHALL consist of a single SET
(see [I-D.ietf-secevent-token]). As per Section 5.3.2 [RFC7231], the
expected media type ("Accept" header) response is "application/json".
To deliver an Event, the Event Transmitter generates an event
delivery message and uses HTTP POST to the configured endpoint with
the appropriate "Accept" and "Content-Type" headers.
POST /Events HTTP/1.1
Host: notify.examplerp.com
Accept: application/json
Authorization: Bearer h480djs93hd8
Content-Type: application/secevent+jwt
eyJhbGciOiJub25lIn0
.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.
Figure 1: Example HTTP POST Request
Upon receipt of the request, the Event Receiver SHALL validate the
JWT structure of the SET as defined in Section 7.2 [RFC7519]. The
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Event Receiver SHALL also validate the SET information as described
in Section 2 [I-D.ietf-secevent-token].
If the SET is determined to be valid, the Event Receiver SHALL
"acknowledge" successful submission by responding with HTTP Status
202 as "Accepted" (see Section 6.3.3 [RFC7231]).
In order to maintain compatibility with other methods of
transmission, the Event Receiver SHOULD NOT include an HTTP response
body representation of the submitted SET or what the SET's pending
status is when acknowledging success. In the case of an error (e.g.
HTTP Status 400), the purpose of the HTTP response body is to
indicate any SET parsing, validation, or cryptographic errors.
The following is a non-normative example of a successful receipt of a
SET.
HTTP/1.1 202 Accepted
Figure 2: Example Successful Delivery Response
Note that the purpose of the "acknowledgement" response is to let the
Event Transmitter know that a SET has been delivered and the
information no longer needs to be retained by the Event Transmitter.
Before acknowledgement, Event Receivers SHOULD ensure they have
validated received SETs and retained them in a manner appropriate to
information retention requirements appropriate to the SET event types
signaled. The level and method of retention of SETs by Event
Receivers is out-of-scope of this specification.
In the Event of a general HTTP error condition, the Event Receiver
MAY respond with an appropriate HTTP Status code as defined in
Section 6 [RFC7231].
When the Event Receiver detects an error parsing or validating a
received SET (as defined by [I-D.ietf-secevent-token]), the Event
Receiver SHALL indicate an HTTP Status 400 error with an error code
as described in Section 2.4.
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The following is an example non-normative error response.
HTTP/1.1 400 Bad Request
Content-Type: application/json
{
"err":"dup",
"description":"SET already received. Ignored."
}
Figure 3: Example HTTP Status 400 Response
2.3. Polling Delivery using HTTP
This method allows an Event Receiver to use HTTP POST (Section 4.3.3
[RFC7231]) to acknowledge SETs and to check for and receive zero or
more SETs. Requests MAY be made at a periodic interval (short
polling) or requests MAY wait pending availability of new SETs using
long polling (see Section 2 [RFC6202]).
The delivery of SETs in this method is facilitated by HTTP POST
requests initiated by the Event Receiver in which:
o The Event Receiver makes a request for available SETs using an
HTTP POST to a pre-arranged endpoint provided by the Event
Transmitter. Or,
o After validating previously received SETs, the Event Receiver
initiates another poll request using HTTP POST that includes
acknowledgement of previous SETs, and waits for the next batch of
SETs.
The purpose of the "acknowledgement" is to inform the Event
Transmitter that has successfully been delivered and attempts to re-
deliver are no longer required. Before acknowledgement, Event
Receivers SHOULD ensure received SETs have been validated and
retained in a manner appropriate to the receiver's retention
requirements. The level and method of retention of SETs by Event
Receivers is out-of-scope of this specification.
2.3.1. Polling HTTP Request Attributes
When initiating a poll request, the Event Receiver constructs a JSON
document that consists of polling request parameters and SET
acknowledgement parameters in the form of JSON attributes.
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The request payloads are delivered in one of two forms as described
in Section 2.3.3 and Section 2.3.4
When making a request, the HTTP header "Content-Type" is set to
"application/json".
The following JSON Attributes are used in a polling request:
Request Processing Parameters
maxEvents
an OPTIONAL JSON integer value indicating the maximum number of
unacknowledged SETs that SHOULD be returned. If more than the
maximum number of SETs are available, the oldest SETs available
SHOULD be returned first. A value of "0" MAY be used by Event
Receivers that would like to perform an acknowledge only
request. This enables the Receiver to use separate HTTP
requests for acknowledgement and reception of SETs. When zero
returned events is requested, the value of the attribute
"returnImmediately" SHALL be ignored as an immediate response
is expected.
returnImmediately
An OPTIONAL JSON boolean value that indicates the Event
Transmitter SHOULD return an immediate response even if no
results are available (short polling). The default value is
"false" indicates the request is to be treated as an HTTP Long
Poll (see Section 2 [RFC6202]). The time out for the request
is part of the Stream configuration which is out of scope of
this specification.
SET Acknowledgment Parameters
ack
Which is an array of Strings that each correspond to the "jti"
of a successfully received SET. If there are no outstanding
SETs to acknowledge, the attribute MAY be omitted. When
acknowledging a SET, the Event Transmitter is released from any
obligation to retain the SET (e.g. for a future re-try to
receive).
setErrs
A JSON Object that contains one or more nested JSON attributes
that correspond to the "jti" of each invalid SET received. The
value of each is a JSON object whose contents is an "err"
attribute and "description" attribute whose value correspond to
the errors described in Section 2.4.
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2.3.2. Polling HTTP Response Attributes
In response to a poll request, the Event Transmitter checks for
available SET events and responds with a JSON document containing the
following JSON attributes:
sets
A JSON object that contains zero or more nested JSON attributes.
Each nested attribute corresponds to the "jti" of a SET to be
delivered and whose value is a JSON String containing the value of
the encoded corresponding SET. If there are no outstanding SETs
to be transmitted, the JSON object SHALL be empty.
moreAvailable
A JSON boolean value that indicates if more unacknowledged SETs
are available to be returned.
When making a response, the HTTP header "Content-Type" is set to
"application/json".
2.3.3. Poll Request
The Event Receiver performs an HTTP POST (see Section 4.3.4
[RFC7231]) to a pre-arranged polling endpoint URI to check for SETs
that are available. Because the Event Receiver has no prior SETs to
acknowledge, the "ack" and "errs" request parameters are omitted.
If after a period of time, negotiated between the Event Transmitter
and Receiver, an Event Transmitter MAY re-issue SETs it has
previously delivered. The Event Receiver SHOULD accept repeat SETs
and acknowledge the SETs regardless of whether the Receiver believes
it has already acknowledged the SETs previously. An Event
Transmitter MAY limit the number of times it attempts to deliver a
SET. Upon abandoning delivery of a SET, the Event Transmitter SHOULD
have a method to notify the Event Receiver of the loss such as
through a status service (not defined by this specification).
If the Event Receiver has received SETs from the Event Transmitter,
the Event Receiver SHOULD parse and validate received SETs to meet
its own requirements and SHOULD acknowledge receipt in a timely (e.g.
minutes) fashion so that the Event Transmitter may mark the SETs as
received. Event Receivers SHOULD acknowledge receipt before taking
any local actions based on the SETs to avoid unnecessary delay in
acknowledgement where possible.
Poll requests have three variations:
Poll Only
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In which an Event Receiver asks for the next set of Events where
no previous SET deliveries are acknowledged (such as in the
initial poll request).
Acknowledge Only
In which an Event Receiver sets the "maxEvents" attribute to "0"
along with "ack" and "err" attributes indicating the Event
Receiver is acknowledging previously received SETs and does not
want to receive any new SETs in response to the request.
Combined Acknowledge and Poll
In which an Event Receiver is both acknowledging previously
received SETs using the "ack" and "err" attributes and will wait
for the next group of SETs in the Event Transmitters response.
2.3.3.1. Poll Only Request
In the case where no SETs were received in a previous poll (see
Figure 10), the Event Receiver simply polls without acknowledgement
parameters ("sets" and "setErrs").
The following is an example request made by an Event Receiver that
has no outstanding SETs to acknowledge and is polling for available
SETs.
The following is a non-normative example poll request to the
endpoint: "https://nofity.exampleidp.com/Events".
POST /Events HTTP/1.1
Host: notify.exampleidp.com
Authorization: Bearer h480djs93hd8
Accept: application/json
{
"returnImmediately":true
}
Figure 4: Example Initial Poll Request
An Event Receiver MAY poll with no parameters at all by passing an
empty JSON object.
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The following is a non-normative example default poll request to the
endpoint: "https://nofity.exampleidp.com/Events".
POST /Events HTTP/1.1
Host: notify.exampleidp.com
Authorization: Bearer h480djs93hd8
Accept: application/json
{}
Figure 5: Example Default Poll Request
2.3.3.2. Acknowledge Only Request
In this variation, the Event Receiver acknowledges previously
received SETs and indicates it does not want to receive SETs in
response by setting the "maxEvents" attribute to "0".
This variation is typically used when an Event Receiver needs to
acknowledge received SETs independently (e.g. on separate threads)
from the process of receiving SETs.
The following is a non-normative example poll with acknowledgement of
SETs received (for example as shown in Figure 9).
POST /Events HTTP/1.1
Host: notify.exampleidp.com
Authorization: Bearer h480djs93hd8
Content-Type: application/json
Authorization: Bearer h480djs93hd8
{
"ack":[
"4d3559ec67504aaba65d40b0363faad8",
"3d0c3cf797584bd193bd0fb1bd4e7d30"
],
"maxEvents":0
}
Figure 6: Example Acknowledge Only equest
2.3.3.3. Poll with Acknowledgement
This variation allows a receiver thread to simultaneously acknowledge
previously received SETs and wait for the next group of SETs in a
single request.
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The following is a non-normative example poll with acknowledgement of
SETs received in Figure 9.
POST /Events HTTP/1.1
Host: notify.exampleidp.com
Authorization: Bearer h480djs93hd8
Content-Type: application/json
Authorization: Bearer h480djs93hd8
{
"ack":[
"4d3559ec67504aaba65d40b0363faad8",
"3d0c3cf797584bd193bd0fb1bd4e7d30"
],
"returnImmediately":false
}
Figure 7: Example Poll With Acknowledgement and No Errors
In the above acknowledgement, the Event Receiver has acknowledged
receipt of two SETs and has indicated it wants to wait until the next
SET is available.
2.3.3.4. Poll with Acknowledgement and Errors
In the case where errors were detected in previously delivered SETs,
the Event Receiver MAY use the "setErrs" attribute to indicate errors
in the following poll request.
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The following is a non-normative example of a response acknowledging
1 error and 1 receipt of two SETs received in Figure 9.
POST /Events HTTP/1.1
Host: notify.exampleidp.com
Authorization: Bearer h480djs93hd8
Content-Type: application/json
Authorization: Bearer h480djs93hd8
{
"ack":["3d0c3cf797584bd193bd0fb1bd4e7d30"],
"setErrs":{
"4d3559ec67504aaba65d40b0363faad8":{
"err":"jwtAud",
"description":"The audience value was incorrect."
}
},
"returnImmediately":true
}
Figure 8: Example Poll Acknowledgement With Error
2.3.4. Poll Response
In response to a poll request, the service provider MAY respond
immediately if SETs are available to be delivered. If no SETs are
available at the time of the request, the Event Transmitter SHALL
delay responding until a SET is available unless the poll request
parameter "returnImmediately" is "true".
As described in Section 2.3.2 a JSON document is returned containing
a number of attributes including "sets" which SHALL contain zero or
more SETs.
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The following is a non-normative example response to the request
shown Section 2.3.3. This example shows two SETs are returned.
HTTP/1.1 200 OK
Content-Type: application/json
Location: https://notify.exampleidp/Events
{
"sets":{
"4d3559ec67504aaba65d40b0363faad8":
"eyJhbGciOiJub25lIn0.
eyJqdGkiOiI0ZDM1NTllYzY3NTA0YWFiYTY1ZDQwYjAzNjNmYWFkOCIsImlhdCI6MTQ
1ODQ5NjQwNCwiaXNzIjoiaHR0cHM6Ly9zY2ltLmV4YW1wbGUuY29tIiwiYXVkIjpbIm
h0dHBzOi8vc2NpbS5leGFtcGxlLmNvbS9GZWVkcy85OGQ1MjQ2MWZhNWJiYzg3OTU5M
2I3NzU0IiwiaHR0cHM6Ly9zY2ltLmV4YW1wbGUuY29tL0ZlZWRzLzVkNzYwNDUxNmIx
ZDA4NjQxZDc2NzZlZTciXSwiZXZlbnRzIjp7InVybjppZXRmOnBhcmFtczpzY2ltOmV
2ZW50OmNyZWF0ZSI6eyJyZWYiOiJodHRwczovL3NjaW0uZXhhbXBsZS5jb20vVXNlcn
MvNDRmNjE0MmRmOTZiZDZhYjYxZTc1MjFkOSIsImF0dHJpYnV0ZXMiOlsiaWQiLCJuY
W1lIiwidXNlck5hbWUiLCJwYXNzd29yZCIsImVtYWlscyJdfX19.",
"3d0c3cf797584bd193bd0fb1bd4e7d30":
"eyJhbGciOiJub25lIn0.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."
}
}
Figure 9: Example Poll Response
In the above example, a two SETs whose "jti" are
"4d3559ec67504aaba65d40b0363faad8" and
"3d0c3cf797584bd193bd0fb1bd4e7d30" are delivered.
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The following is a non-normative example response to the request
shown Section 2.3.3 showing no new SETs or unacknowledged SETs are
available.
HTTP/1.1 200 OK
Content-Type: application/json
Location: https://notify.exampleidp/Events
{
"sets":{ }
}
Figure 10: Example No SETs Poll Response
Upon receiving the JSON document (e.g. as shown in Figure 9), the
Event Receiver parses and verifies the received SETs and notifies the
Event Transmitter via the next poll request to the Event Transmitter
as described in Section 2.3.3.3 or Section 2.3.3.4.
2.4. Error Response Handling
If a SET is invalid, the following error codes are defined:
+-----------+-------------------------------------------------------+
| Err Value | Description |
+-----------+-------------------------------------------------------+
| json | Invalid JSON object. |
| jwtParse | Invalid or unparsable JWT or JSON structure. |
| jwtHdr | In invalid JWT header was detected. |
| jwtCrypto | Unable to parse due to unsupported algorithm. |
| jws | Signature was not validated. |
| jwe | Unable to decrypt JWE encoded data. |
| jwtAud | Invalid audience value. |
| jwtIss | Issuer not recognized. |
| setType | An unexpected Event type was received. |
| setParse | Invalid structure was encountered such as an |
| | inability to parse or an incomplete set of Event |
| | claims. |
| setData | SET event claims incomplete or invalid. |
| dup | A duplicate SET was received and has been ignored. |
+-----------+-------------------------------------------------------+
Table 1: SET Errors
An error response SHALL include a JSON object which provides details
about the error. The JSON object includes the JSON attributes:
err
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A value which is a keyword that describes the error (see Table 1).
description
A human-readable text that provides additional diagnostic
information.
When included as part of an HTTP Status 400 response, the above JSON
is the HTTP response body (see Figure 3). When included as part of a
batch of SETs, the above JSON is included as part of the "setErrs"
attribute as defined in Section 2.3.2 and Section 2.3.3.4
3. Authentication and Authorization
The SET delivery methods described in this specification are based
upon HTTP and depend on the use of TLS and/or standard HTTP
authentication and authorization schemes as per [RFC7235]. For
example, the following methodologies could be used among others:
TLS Client Authentication
Event delivery endpoints MAY request TLS mutual client
authentication. See Section 7.3 [RFC5246].
Bearer Tokens
Bearer tokens [RFC6750] MAY be used when combined with TLS and a
token framework such as OAuth 2.0 [RFC6749]. For security
considerations regarding the use of bearer tokens in SET delivery
see Section 4.4.1.
Basic Authentication
Usage of basic authentication should be avoided due to its use of
a single factor that is based upon a relatively static, symmetric
secret. Implementers SHOULD combine the use of basic
authentication with other factors. The security considerations of
HTTP BASIC, are well documented in [RFC7617] and SHOULD be
considered along with using signed SETs (see SET Payload
Authentication below).
SET Payload Authentication
In scenarios where SETs are signed and the delivery method is HTTP
POST (see Section 2.2), Event Receivers MAY elect to use Basic
Authentication or not to use HTTP or TLS based authentication at
all. See Section 4.1 for considerations.
As per Section 4.1 of [RFC7235], a SET delivery endpoint SHALL
indicate supported HTTP authentication schemes via the "WWW-
Authenticate" header.
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Because SET Delivery describes a simple function, authorization for
the ability to pick-up or deliver SETs can be derived by considering
the identity of the SET issuer, or via an authentication method
above. This specification considers authentication as a feature to
prevent denial-of-service attacks. Because SETs are not commands
(see ), Event Receivers are free to ignore SETs that are not of
interest.
For illustrative purposes only, SET delivery examples show an OAuth2
bearer token value [RFC6750] in the authorization header. This is
not intended to imply that bearer tokens are preferred. However, the
use of bearer tokens in the specification does reflect common
practice.
3.1. Use of Tokens as Authorizations
When using bearer tokens or proof-of-possession tokens that represent
an authorization grant such as issued by OAuth (see [RFC6749]),
implementers SHOULD consider the type of authorization granted, any
authorized scopes (see Section 3.3 of [RFC6749]), and the security
subject(s) that SHOULD be mapped from the authorization when
considering local access control rules. Section 6 of the OAuth
Assertions draft [RFC7521], documents common scenarios for
authorization including:
o Clients using an assertion to authenticate and/or act on behalf of
itself;
o Clients acting on behalf of a user; and,
o A Client acting on behalf of an anonymous user (e.g., see next
section).
When using OAuth authorization tokens, implementers MUST take into
account the threats and countermeasures documented in the security
considerations for the use of client authorizations (see Section 8 of
[RFC7521]). When using other token formats or frameworks,
implementers MUST take into account similar threats and
countermeasures, especially those documented by the relevant
specifications.
4. Security Considerations
4.1. Authentication Using Signed SETs
In scenarios where HTTP authorization or TLS mutual authentication
are not used or are considered weak, JWS signed SETs SHOULD be used
(see [RFC7515] and Security Considerations
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[I-D.ietf-secevent-token]). This enables the Event Receiver to
validate that the SET issuer is authorized to deliver SETs.
4.2. HTTP Considerations
SET delivery depends on the use of Hypertext Transfer Protocol and
thus subject to the security considerations of HTTP Section 9
[RFC7230] and its related specifications.
As stated in Section 2.7.1 [RFC7230], an HTTP requestor MUST NOT
generate the "userinfo" (i.e., username and password) component (and
its "@" delimiter) when an "http" URI reference is generated with a
message as they are now disallowed in HTTP.
4.3. TLS Support Considerations
SETs contain sensitive information that is considered PII (e.g.
subject claims). Therefore, Event Transmitters and Event Receivers
MUST require the use of a transport-layer security mechanism. Event
delivery endpoints MUST support TLS 1.2 [RFC5246] and MAY support
additional transport-layer mechanisms meeting its security
requirements. When using TLS, the client MUST perform a TLS/SSL
server certificate check, per [RFC6125]. Implementation security
considerations for TLS can be found in "Recommendations for Secure
Use of TLS and DTLS" [RFC7525].
4.4. Authorization Token Considerations
When using authorization tokens such as those issued by OAuth 2.0
[RFC6749], implementers MUST take into account threats and
countermeasures documented in Section 8 of [RFC7521].
4.4.1. Bearer Token Considerations
Due to the possibility of interception, Bearer tokens MUST be
exchanged using TLS.
Bearer tokens MUST have a limited lifetime that can be determined
directly or indirectly (e.g., by checking with a validation service)
by the service provider. By expiring tokens, clients are forced to
obtain a new token (which usually involves re-authentication) for
continued authorized access. For example, in OAuth2, a client MAY
use OAuth token refresh to obtain a new bearer token after
authenticating to an authorization server. See Section 6 of
[RFC6749].
Implementations supporting OAuth bearer tokens need to factor in
security considerations of this authorization method [RFC7521].
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Since security is only as good as the weakest link, implementers also
need to consider authentication choices coupled with OAuth bearer
tokens. The security considerations of the default authentication
method for OAuth bearer tokens, HTTP BASIC, are well documented in
[RFC7617], therefore implementers are encouraged to prefer stronger
authentication methods. Designating the specific methods of
authentication and authorization are out-of-scope for the delivery of
SET tokens, however this information is provided as a resource to
implementers.
5. Privacy Considerations
If a SET needs to be retained for audit purposes, JWS MAY be used to
provide verification of its authenticity.
Event Transmitters SHOULD attempt to specialize Event Streams so that
the content is targeted to the specific business and protocol needs
of subscribers.
When sharing personally identifiable information or information that
is otherwise considered confidential to affected users, Event
Transmitters and Receivers MUST have the appropriate legal agreements
and user consent or terms of service in place.
The propagation of subject identifiers can be perceived as personally
identifiable information. Where possible, Event Transmitters and
Receivers SHOULD devise approaches that prevent propagation -- for
example, the passing of a hash value that requires the subscriber to
already know the subject.
6. IANA Considerations
There are no IANA considerations.
7. References
7.1. Normative References
[I-D.ietf-secevent-token]
Hunt, P., Denniss, W., Ansari, M., and M. Jones, "Security
Event Token (SET)", draft-ietf-secevent-token-00 (work in
progress), January 2017.
[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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[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.
[RFC5988] Nottingham, M., "Web Linking", RFC 5988,
DOI 10.17487/RFC5988, October 2010,
<https://www.rfc-editor.org/info/rfc5988>.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
2011, <https://www.rfc-editor.org/info/rfc6125>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <https://www.rfc-editor.org/info/rfc7159>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>.
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517,
DOI 10.17487/RFC7517, May 2015,
<https://www.rfc-editor.org/info/rfc7517>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <https://www.rfc-editor.org/info/rfc7525>.
[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>.
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7.2. Informative References
[openid-connect-core]
NRI, "OpenID Connect Core 1.0", Nov 2014.
[POSIX.1] Institute of Electrical and Electronics Engineers, "The
Open Group Base Specifications Issue 7", IEEE Std 1003.1,
2013 Edition, 2013.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.
[RFC6202] Loreto, S., Saint-Andre, P., Salsano, S., and G. Wilkins,
"Known Issues and Best Practices for the Use of Long
Polling and Streaming in Bidirectional HTTP", RFC 6202,
DOI 10.17487/RFC6202, April 2011,
<https://www.rfc-editor.org/info/rfc6202>.
[RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
RFC 6749, DOI 10.17487/RFC6749, October 2012,
<https://www.rfc-editor.org/info/rfc6749>.
[RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
Framework: Bearer Token Usage", RFC 6750,
DOI 10.17487/RFC6750, October 2012,
<https://www.rfc-editor.org/info/rfc6750>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014,
<https://www.rfc-editor.org/info/rfc7230>.
[RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Authentication", RFC 7235,
DOI 10.17487/RFC7235, June 2014,
<https://www.rfc-editor.org/info/rfc7235>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC7516] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
RFC 7516, DOI 10.17487/RFC7516, May 2015,
<https://www.rfc-editor.org/info/rfc7516>.
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[RFC7521] Campbell, B., Mortimore, C., Jones, M., and Y. Goland,
"Assertion Framework for OAuth 2.0 Client Authentication
and Authorization Grants", RFC 7521, DOI 10.17487/RFC7521,
May 2015, <https://www.rfc-editor.org/info/rfc7521>.
[RFC7617] Reschke, J., "The 'Basic' HTTP Authentication Scheme",
RFC 7617, DOI 10.17487/RFC7617, September 2015,
<https://www.rfc-editor.org/info/rfc7617>.
[saml-core-2.0]
Internet2, "Assertions and Protocols for the OASIS
Security Assertion Markup Language (SAML) V2.0", March
2005.
Appendix A. Other Streaming Specifications
[[EDITORS NOTE: This section to be removed prior to publication]]
The following pub/sub, queuing, streaming systems were reviewed as
possible solutions or as input to the current draft:
XMPP Events
The WG considered the XMPP events ands its ability to provide a
single messaging solution without the need for both polling and push
modes. The feeling was the size and methodology of XMPP was to far
apart from the current capabilities of the SECEVENTs community which
focuses in on HTTP based service delivery and authorization.
Amazon Simple Notification Service
Simple Notification Service, is a pub/sub messaging product from AWS.
SNS supports a variety of subscriber types: HTTP/HTTPS endpoints, AWS
Lambda functions, email addresses (as JSON or plain text), phone
numbers (via SMS), and AWS SQS standard queues. It doesn't directly
support pull, but subscribers can get the pull model by creating an
SQS queue and subscribing it to the topic. Note that this puts the
cost of pull support back onto the subscriber, just as it is in the
push model. It is not clear that one way is strictly better than the
other; larger, sophisticated developers may be happy to own message
persistence so they can have their own internal delivery guarantees.
The long tail of OIDC clients may not care about that, or may fail to
get it right. Regardless, I think we can learn something from the
Delivery Policies supported by SNS, as well as the delivery controls
that SQS offers (e.g. Visibility Timeout, Dead-Letter Queues). I'm
not suggesting that we need all of these things in the spec, but they
give an idea of what features people have found useful.
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Other information:
o API Reference:
http://docs.aws.amazon.com/AWSSimpleQueueService/latest/
APIReference/Welcome.html
o Visibility Timeouts:
http://docs.aws.amazon.com/AWSSimpleQueueService/latest/
SQSDeveloperGuide/sqs-visibility-timeout.html
Apache Kafka
Apache Kafka is an Apache open source project based upon TCP for
distributed streaming. It prescribes some interesting general
purpose features that seem to extend far beyond the simpler streaming
model SECEVENTs is after. A comment from MS has been that Kafka does
an acknowledge with poll combination event which seems to be a
performance advantage. See: https://kafka.apache.org/intro
Google Pub/Sub
Google Pub Sub system favours a model whereby polling and
acknowledgement of events is done as separate endpoints as separate
functions.
Information:
o Cloud Overview - https://cloud.google.com/pubsub/
o Subscriber Overview - https://cloud.google.com/pubsub/docs/
subscriber
o Subscriber Pull(poll) - https://cloud.google.com/pubsub/docs/pull
Appendix B. Acknowledgments
The editors would like to thanks the members of the SCIM WG which
began discussions of provisioning events starting with: draft-hunt-
scim-notify-00 in 2015.
The editor would like to thank the participants in the the SECEVENTS
working group for their support of this specification.
Appendix C. Change Log
Draft 00 - PH - Based on draft-hunt-secevent.distribution with the
following additions:
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o Removed Control Plane from specification
o Added new HTTP Polling delivery method
o Added general HTTP security considerations
o Added authentication and authorization
o Revised Verify Event to work with both types of delivery
Draft 01 - PH - Removed Verification section per feedback from
IETF99.
Draft 02 - MS -
o Minor editorial improvements
o Removed Identity Provider / Relying Party Terminology
o Changed boilerplate language according to RFC8174
This draft was based on draft-hunt-secevent.distribution revision
history:
o Draft 00 - PH - First Draft based on reduced version of draft-
hunt-idevent-distribution
o Draft 01 - PH -
* Reworked terminology to match new WG Transmitter/Receiver terms
* Reworked sections into Data Plane vs. Control Plane
* Removed method transmission registry in order to simplify the
specification
* Made Create, Update operations optional for Control Plane (Read
is MTI)
o Draft 02 - PH
* Added iss metadata for Event Stream
* Changed to using JWKS_uri for issuer and receiver.
* Control Plane sections moved to draft-hunt-secevent-stream-mgmt
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* Added support for delivering multiple events using HTTP POST
polling
Authors' Addresses
Phil Hunt (editor)
Oracle Corporation
Email: phil.hunt@yahoo.com
Marius Scurtescu
Google
Email: mscurtescu@google.com
Morteza Ansari
Cisco
Email: morteza.ansari@cisco.com
Anthony Nadalin
Microsoft
Email: tonynad@microsoft.com
Annabelle Richard Backman
Amazon
Email: richanna@amazon.com
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