Network Working Group M. West Internet-Draft Google, Inc Intended status: Standards Track October 6, 2015 Expires: April 8, 2016 Content Security Policy Directive Registry draft-west-webappsec-csp-reg-00 Abstract This document establishes an Internet Assigned Number Authority (IANA) registry for Content Security Policy directives. It populates the registry with the directives defined in the CSP specification. 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 http://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 April 8, 2016. Copyright Notice Copyright (c) 2015 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 (http://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. West Expires April 8, 2016 [Page 1] Internet-Draft webappsec-csp-reg October 2015 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Use of the Registry . . . . . . . . . . . . . . . . . . . . . 2 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 4.1. Content Security Policy directives Registry . . . . . . . 3 4.2. Registration Policy for Content Security Policy directives . . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 6.1. Normative References . . . . . . . . . . . . . . . . . . 4 6.2. Informative References . . . . . . . . . . . . . . . . . 5 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction The Content Security Policy specification [CSP] defines a mechanism by which web developers can control the resources which a particular page can fetch or execute, as well as a number of security-relevant policy decisions. The policy language specified in that document consists of an extensible set of "directives", each of which controls a specific resource type or policy decision. This specification establishes a registry to ensure that extensions to CSP are listed and standardized. 2. Terminology 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]. 3. Use of the Registry Content Security Policy directives MUST be documented in a readily available public specification in order to be registered by IANA. This documentation MUST fully explain the syntax, intended usage, and semantics of the directive. The intent of this requirement is to assure interoperable independent implementations, and to prevent accidental namespace collisions between implementations of dissimilar features. Documents defining new Content Security Policy directives MUST register them with IANA, as described in Section 4. The IANA West Expires April 8, 2016 [Page 2] Internet-Draft webappsec-csp-reg October 2015 registration policy for such parameters is "Specification Required, Designated Expert", and is further discussed in Section 4.2. 4. IANA Considerations This specification creates a new IANA registry named "Content Security Policy directives". 4.1. Content Security Policy directives Registry New Content Security Policy directives, and updates to existing directives, MUST be registered with IANA. When registering a new Content Security Policy directive, the following information MUST be provided: o The directive's name (which MUST be an ASCII string) o A reference to the readily available public specification defining the new directive's syntax, usage, and semantics. The following table contains the initial values for this registry: +-----------------+-----------+ | Directive Name | Reference | +-----------------+-----------+ | base-uri | [CSP] | | child-src | [CSP] | | connect-src | [CSP] | | default-src | [CSP] | | font-src | [CSP] | | form-action | [CSP] | | frame-ancestors | [CSP] | | frame-src | [CSP] | | img-src | [CSP] | | media-src | [CSP] | | object-src | [CSP] | | plugin-types | [CSP] | | report-uri | [CSP] | | sandbox | [CSP] | | script-src | [CSP] | | style-src | [CSP] | +-----------------+-----------+ West Expires April 8, 2016 [Page 3] Internet-Draft webappsec-csp-reg October 2015 4.2. Registration Policy for Content Security Policy directives As per the terminology in [RFC5226] and actions accorded to such a role, the registration policy for Content Security Policy directives is "Specification Required, Designated Expert" (the former implies the latter). The Designated Expert, when deliberating on whether to include a new directive in the registry, MAY use the criteria provided below to reach a decision. These are not an exhaustive list, but representative of the issues to consider when rendering an equitable decision): o Content Security Policy is a restrictive feature, which allows web developers to deny themselves access to resources and APIs which would otherwise be available. Deploying Content Security Policy is, therefore, a strict reduction in risk. The expert should carefully consider whether proposed directives would violate this property. o Granular directives are valuable, but the expert should strive to strike a reasonable balance between providing developers with all the knobs and switches possible, and providing only those with known security implications. 5. Security Considerations The registry in this document does not in itself have security implications. The directives specified, however, certainly do. The documents referenced when registering new directives MUST contain detailed security and privacy considerations sections, and SHOULD contain usage information which informs web developers as to the directive's expected implementation. 6. References 6.1. Normative References [CSP] West, M. and D. Veditz, "Content Security Policy", n.d., . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ RFC2119, March 1997, . West Expires April 8, 2016 [Page 4] Internet-Draft webappsec-csp-reg October 2015 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, DOI 10.17487/RFC5226, May 2008, . 6.2. Informative References [RFC5341] Jennings, C. and V. Gurbani, "The Internet Assigned Number Authority (IANA) tel Uniform Resource Identifier (URI) Parameter Registry", RFC 5341, DOI 10.17487/RFC5341, September 2008, . Appendix A. Acknowledgements I've cargo-culted this document from [RFC5341], so thank you to Cullen Jennings and Vijay K. Gurbani for giving me a reasonable template to work within. Author's Address Mike West Google, Inc Email: mkwst@google.com URI: https://mikewest.org/ West Expires April 8, 2016 [Page 5]