CoAP: Echo, Request-Tag, and Token Processing
draft-ietf-core-echo-request-tag-11
CoRE Working Group C. Amsuess
Internet-Draft
Updates: 7252 (if approved) J. Mattsson
Intended status: Standards Track G. Selander
Expires: May 6, 2021 Ericsson AB
November 02, 2020
CoAP: Echo, Request-Tag, and Token Processing
draft-ietf-core-echo-request-tag-11
Abstract
This document specifies enhancements to the Constrained Application
Protocol (CoAP) that mitigate security issues in particular use
cases. The Echo option enables a CoAP server to verify the freshness
of a request or to force a client to demonstrate reachability at its
claimed network address. The Request-Tag option allows the CoAP
server to match block-wise message fragments belonging to the same
request. This document updates RFC7252 with respect to the client
Token processing requirements, forbidding non-secure reuse of Tokens
to ensure binding of response to request when CoAP is used with a
security protocol, and with respect to amplification mitigation,
where the use of Echo is now recommended.
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 May 6, 2021.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
Amsuess, et al. Expires May 6, 2021 [Page 1]
Internet-Draft CoAP: ERT November 2020
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
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 . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Request Freshness and the Echo Option . . . . . . . . . . . . 4
2.1. Request Freshness . . . . . . . . . . . . . . . . . . . . 4
2.2. The Echo Option . . . . . . . . . . . . . . . . . . . . . 5
2.2.1. Echo Option Format . . . . . . . . . . . . . . . . . 5
2.3. Echo Processing . . . . . . . . . . . . . . . . . . . . . 6
2.4. Applications of the Echo Option . . . . . . . . . . . . . 10
3. Protecting Message Bodies using Request Tags . . . . . . . . 11
3.1. Fragmented Message Body Integrity . . . . . . . . . . . . 11
3.2. The Request-Tag Option . . . . . . . . . . . . . . . . . 12
3.2.1. Request-Tag Option Format . . . . . . . . . . . . . . 12
3.3. Request-Tag Processing by Servers . . . . . . . . . . . . 13
3.4. Setting the Request-Tag . . . . . . . . . . . . . . . . . 14
3.5. Applications of the Request-Tag Option . . . . . . . . . 15
3.5.1. Body Integrity Based on Payload Integrity . . . . . . 15
3.5.2. Multiple Concurrent Block-wise Operations . . . . . . 16
3.5.3. Simplified Block-Wise Handling for Constrained
Proxies . . . . . . . . . . . . . . . . . . . . . . . 17
3.6. Rationale for the Option Properties . . . . . . . . . . . 17
3.7. Rationale for Introducing the Option . . . . . . . . . . 18
3.8. Block2 / ETag Processing . . . . . . . . . . . . . . . . 18
4. Token Processing for Secure Request-Response Binding . . . . 18
4.1. Request-Response Binding . . . . . . . . . . . . . . . . 18
4.2. Updated Token Processing Requirements for Clients . . . . 19
5. Security Considerations . . . . . . . . . . . . . . . . . . . 19
5.1. Token reuse . . . . . . . . . . . . . . . . . . . . . . . 21
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 22
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 23
Show full document text