HTTP K. Oku Internet-Draft J. Iyengar Intended status: Informational Fastly Expires: 14 February 2022 13 August 2021 Self-Tracing for HTTP draft-kazuho-httpbis-selftrace-00 Abstract This document registers a "Well-Known URI" for exposing state of an HTTP connection to the peer using formats such as qlog schema [QLOG]. 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 14 February 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 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. Oku & Iyengar Expires 14 February 2022 [Page 1] Internet-Draft Self-Tracing for HTTP August 2021 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Notational Conventions . . . . . . . . . . . . . . . . . 2 2. The Self-Trace Well-Known URI . . . . . . . . . . . . . . . . 2 3. Security Considerations . . . . . . . . . . . . . . . . . . . 3 3.1. Cross-Origin Attacks . . . . . . . . . . . . . . . . . . 3 3.2. Coalescing Proxy Acting as Client . . . . . . . . . . . . 3 3.3. Connections Serving Multiple Origins . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 5.1. Normative References . . . . . . . . . . . . . . . . . . 4 5.2. Informative References . . . . . . . . . . . . . . . . . 4 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction One challenge regarding HTTP ([HTTP]) performance or stability analysis is obtaining the sender-side trace of connections. End- users of HTTP who face issues do not have access to the server-side traces. It is also difficult for server-side operators to retain enough amount of fine-grained traces that they can consult when their end-users report issues. Also, there are privacy concerns regarding retaining fine-grained traces. This challenge can be overcome if the server exposes the trace of each HTTP connection on that same connection. When users experience issues, they can report to the server operators with the traces that they obtained on the HTTP connections that suffered. The privacy concern is mitigated as the users will be submitting the trace actively. 1.1. Notational Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. The Self-Trace Well-Known URI When a server receives a GET request at the Self-Trace Well-Known URI, it starts streaming event information that occur on the connection on which that request was received. Note however that, depending on the type of the trace being collected, sending chunks of a trace might cause additonal events that in turn generate more chunks that have to be sent. To prevent Oku & Iyengar Expires 14 February 2022 [Page 2] Internet-Draft Self-Tracing for HTTP August 2021 this infinite feedback loop, a server SHOULD suspend the transmission of self-trace when the self-trace becomes the only HTTP request being inflight on an HTTP connection. When a new HTTP request is opened on the same HTTP connection, the server can resume the transmission of the trace. 3. Security Considerations 3.1. Cross-Origin Attacks To prevent cross-origin attacks, web browser access to the self-trace MUST be resticted to the same origin [FETCH]. 3.2. Coalescing Proxy Acting as Client When a forward proxy that coalesces HTTP requests from multiple end- clients connect to an HTTP server that can serve the self-trace, and if one of the end-clients request the self-trace, the provided trace might contain information regarding requests bein issued by other end-clients. To prevent this attack, servers SHOULD serve self-trace only when HTTPS is being used. The assumption here is that when HTTPS is being used, end-clients are directly connected to the server. 3.3. Connections Serving Multiple Origins Sometimes, reverse proxies are configured as such that one HTTP connection can be used for serving multiple origins maintained by different entities (e.g., CDN using an X.509 certificate that contains multiple customers). In such deployments, a malicious origin might use a script running on a web browser to fetch the self- trace that conains traffic information related to other origins colocated, then upload the fetched trace to extract information. To prevent such attacks, reverse proxies used for forwarding HTTP requests to multiple origins belonging to different entities SHOULD do either of the following: * Serve self-trace only from an origin maintained by the operator of the reverse proxy. * Serve self-trace during only when requests for one origin is inflight on a given connection. Oku & Iyengar Expires 14 February 2022 [Page 3] Internet-Draft Self-Tracing for HTTP August 2021 4. IANA Considerations This specification registers the following value in the "Well-Known URIs" registry established by [RFC5785]: URI suffix: self-trace Change controller: IETF Specification document(s): this document Related information: N/A 5. References 5.1. Normative References [HTTP] Fielding, R. T., Nottingham, M., and J. Reschke, "HTTP/1.1", Work in Progress, Internet-Draft, draft-ietf- httpbis-messaging-17, 25 July 2021, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known Uniform Resource Identifiers (URIs)", RFC 5785, DOI 10.17487/RFC5785, April 2010, . 5.2. Informative References [FETCH] WHATWG, "Fetch - Living Standard", n.d., . [I-D.benfield-http2-debug-state] Benfield, C. and B. Fitzpatrick, "HTTP/2 Implementation Debug State", Work in Progress, Internet-Draft, draft- benfield-http2-debug-state-01, 10 August 2016, . Oku & Iyengar Expires 14 February 2022 [Page 4] Internet-Draft Self-Tracing for HTTP August 2021 [QLOG] Marx, R., Niccolini, L., and M. Seemann, "Main logging schema for qlog", Work in Progress, Internet-Draft, draft- ietf-quic-qlog-main-schema-00, 10 June 2021, . Appendix A. Acknowledgements In [I-D.benfield-http2-debug-state], Cory Benfield presented the idea of exposing a snapshot of an HTTP connection to the client. The key difference from that proposal is that this specification defines a way to "stream" the states as they change. Authors' Addresses Kazuho Oku Fastly Email: kazuhooku@gmail.com Jana Iyengar Fastly Email: jri.ietf@gmail.com Oku & Iyengar Expires 14 February 2022 [Page 5]