Internet DRAFT - draft-damjanovic-websockets-nomasking
draft-damjanovic-websockets-nomasking
HTTP D. Damjanovic
Internet-Draft Microsoft
Intended status: Experimental 27 February 2024
Expires: 30 August 2024
WebSocket Extension to disable masking
draft-damjanovic-websockets-nomasking-02
Abstract
The WebSocket protocol specifies that all frames sent from the client
to the server must be masked. This was introduced as a protection
against a possible attack on the infrastructure. With careful
consideration, the masking could be omitted when intermediaries do
not have access to the unencrypted traffic.
This specification introduces a WebSocket extension that disables the
mandatory masking of frames sent from the client to the server. The
extension is allowed only if the client uses an encrypted connection.
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
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 30 August 2024.
Copyright Notice
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document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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extracted from this document must include Revised BSD License text as
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 2
3. The "no-masking" extension . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
6. Normative References . . . . . . . . . . . . . . . . . . . . 3
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
The WebSocket protocol specifies that all frames sent from the client
to the server must be masked [RFC6455]. This was introduced as a
protection against a possible attack on the infrastructure described
in Section 10.3 of [RFC6455]. The attack can be performed on
intermediaries, such as proxies and it could cause cache poisoning.
Using end-to-end encryption, the attack can be mitigated without the
use of masking. This is because every intermediary will be denied
access to the unencrypted traffic, which prevents the caching attack.
The masking has been made mandatory for the connection using TLS to
protect the infrastructure that is behind TLS terminating proxies.
This specification introduces a WebSocket extension that disables the
masking of frames sent from the client to the server. The support
for the extension will be advertised by the client (see Section 9 of
[RFC6455]). The server may accept or decline the extension. The
client can advertise the extension only if an encrypted connection.
2. Conventions and Definitions
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.
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3. The "no-masking" extension
The "no-masking" extension is negotiated using the WebSocket
extension mechanism described in Section 9 of [RFC6455]. The client
advertises support for the extension by sending "no-masking" in the
list of supported extensions sent in the "Sec-WebSocket-Extensions"
header field. The server accepts the extension, by sending "no-
masking" in the "Sec-WebSocket-Extensions" header value.
The client MUST NOT send the extension if a non-secure connection is
used.
If the "no-masking" extension is negotiated the client and the server
behavior are:
* The client MUST send data to the server without masking. The
client sets the field "frame-masked" to 0 on all frames. As
defined in [RFC6455], the field "frame-masking-key" will not be
present.
* The server must only accept frames with the field "frame-masked"
set to 0. If the server receives a frame with the field "frame-
masked" set to 1, it MUST close the connection with the status
code 1002 define in Section 7.4.1 of [RFC6455].
4. Security Considerations
TBA
5. IANA Considerations
IANA has registered the following WebSocket extension name in the
"WebSocket Extension Name Registry" defined in [RFC6455].
Extension Identifier: no-masking
Extension Common Name: Disable the WebSocket client-to-server masking
Extension Definition: This document.
Known Incompatible Extensions: None
The "no-masking" extension name is used in the "Sec-WebSocket-
Extensions" header in the WebSocket opening handshake to negotiate
disabling of the client-to-server masking.
6. Normative References
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[RFC6455] Fette, I. and A. Melnikov, "The WebSocket Protocol",
RFC 6455, DOI 10.17487/RFC6455, December 2011,
<https://www.rfc-editor.org/info/rfc6455>.
[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>.
[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>.
Acknowledgments
Author's Address
Dragana Damjanovic
Microsoft
Email: dragana.damjano@gmail.com
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