Edit comment LC-2015 for Mobile Web Best Practices Working Group

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Comment LC-2015

Comment Shortname:

Commenter: Sean Owen <srowen@google.com>

Message-id:

Section of the document concerned:

[Free text description]Document as a wholeContent Transformation Guidelines 1.0 Abstract Status of this Document Table of Contents Appendices 1 Introduction (Non-Normative) 1.1 Purpose 1.2 Audience 1.3 Scope 1.4 Summary of Requirements 2 Terminology (Normative) 2.1 Types of Proxy "A transparent proxy is a proxy that does not modify the req... A non-transparent proxy is a proxy that modifies the request... 2.2 Types of Transformation Restructuring content is a process whereby the original layo... Recoding content is a process whereby the layout of the cont... Optimizing content includes removing redundant white space,... 3 Conformance (Normative) 3.1 Classes of Product 3.2 Normative and Informative Parts 3.3 Normative Language for Conformance Requirements 3.4 Content Deployment Conformance 3.5 Transformation Deployment Conformance 4 Behavior of Components (Normative) 4.1 Proxy Forwarding of Request 4.1.1 Applicable HTTP Methods 4.1.2 no-transform directive in Request 4.1.3 Treatment of Requesters that are not Web browsers 4.1.4 Serving Cached Responses 4.1.5 Alteration of HTTP Header Values In this section, the concept of "Web site" is used (rather t... 4.1.5.1 Content Tasting 4.1.5.2 Avoiding "Request Unacceptable" Responses 4.1.5.3 User Selection of Restructured Experience 4.1.5.4 Sequence of Requests 4.1.5.5 Original Headers 4.1.6 Additional HTTP Headers 4.1.6.1 Proxy Treatment of Via Header 4.2 Server Response to Proxy 4.2.1 Use of HTTP 406 Status 4.2.2 Server Origination of Cache-Control: no-transform Including a Cache-Control: no-transform directive can disrup... 4.2.3 Varying Representations 4.2.3.1 Use of Vary HTTP Header 4.2.3.2 Indication of Intended Presentation Media Type of Representation 4.3 Proxy Forwarding of Response to User Agent 4.3.1 Receipt of Cache-Control: no-transform 4.3.2 Receipt of Warning: 214 Transformation Applied 4.3.3 Server Rejection of HTTP Request 4.3.4 Receipt of Vary HTTP Header 4.3.5 Link to "handheld" Representation 4.3.6 Proxy Decision to Transform 4.3.6.1 Alteration of Response 4.3.6.2 HTTPS Link Re-writing 5 Testing (Normative) A References B Example Transformation Interactions (Non-Normative) B.1 Basic Content Tasting by Proxy B.2 Optimization based on Previous Server Interaction B.3 Optimization based on Previous Server Interaction, Server has Changed its Operation B.4 Server Response Indicating that this Representation is Intended for the Target Device B.5 Server Response Indicating that another Representation is Intended for the Target Device C Applicability to Transforming Solutions which are Out of Scope (Non-Normative) D Scope for Future Work (Non-Normative) D.1 POWDER D.2 link HTTP Header D.3 Sources of Device Information D.4 Inter Proxy Communication D.5 Amendment to and Refinement of HTTP E Administrative Arrangements (Non-Normative) F Acknowledgments (Non-Normative)
or

Refinement of the section concerned:

Status:

open proposal pending resolved_yes resolved_no resolved_partial other assigned to Nobody

Type: substantive editorial typo question general comment undefined

Resolution status:

Response drafted Resolution implemented Reply sent to commenter

Response status:

No response from Commenter yet Commenter approved disposition Commenter objected to disposition
Commenter's response (URI):

Comment:

4.3.6.2 I think the Note here is a good one, but may be worth
expanding, since it is apparently already unclear to some how HTTPS
works here. The very purpose of HTTPS is to ensure that content is not
modified or read by third parties in transit, which means a
transforming proxy cannot jump into an HTTPS conversation between
mobile device and origin server. So there's not actually a question of
whether it's illegal or unethical -- it's simply not possible (unless
you have cracked SSL). It can only create a secure connection between
the mobile device and itself, and between itself and the origin
server. This is indeed a situation that the end user needs to
understand:

I suggest wording along these lines, take it or leave it as you see fit --

URIs which begin with the https scheme, when accessed, are secured
against eavesdropping and modification by third parties by the SSL
protocol. It is therefore not possible for a third-party transforming
proxy to participate directly in such a connection between mobile
device and origin server. Transforming proxies may still transform
content of https resources, but at best, it involves creating a
separate secure connection between device and proxy, and between proxy
and origin server. These communications are secure but the secured
content is of course visible to the transforming proxy. This may of
course be undesirable to an end user.

Therefore if a proxy rewrites https links, replacements links MUST at
least use the https scheme as well, and the proxy MUST use https to
communicate with the origin server. In addition the proxy MUST clearly
advise the user that the potentially sensitive contents of the
communication will be visible to the proxy, and must give the user an
option to opt out.

Related issues: (space separated ids)

WG Notes: [Needs to be checked after editorial re-writing] See: http://www.w3.org/2008/10/07-bpwg-minutes.html#item02 Final resolution: - Accept the thrust of Tom's submission on HTTPS, and editor to make sure that the wording is beefed up (e.g. by saying that if a proxy rewrites HTTPS ... rather than saying a proxy MAY) to make it clear that if you _must_ do it the user MUST know and MUST have a choice

Resolution: We agree and have added text to this section that goes some way to addressing your concern.

(Please make sure the resolution is adapted for public consumption)