W3C home > Mailing lists > Public > public-webappsec@w3.org > January 2015

Re: [CSP] Clarifications regarding the HTTP LINK Header

From: Mike West <mkwst@google.com>
Date: Tue, 20 Jan 2015 11:39:32 +0100
Message-ID: <CAKXHy=c0U6YbG=EwvtcZZdB5J-EVPRU2vR-TME8+_3HWfNj9vw@mail.gmail.com>
To: Brian Smith <brian@briansmith.org>
Cc: Anne van Kesteren <annevk@annevk.nl>, Deian Stefan <deian@cs.stanford.edu>, Brad Hill <hillbrad@fb.com>, Ilya Grigorik <ilya@igvita.com>, Boris Zbarsky <bzbarsky@mit.edu>, "public-webappsec@w3.org" <public-webappsec@w3.org>
On Mon, Jan 19, 2015 at 10:53 PM, Brian Smith <brian@briansmith.org> wrote:

> I suggest you replace "In practice, this implies that user agents
> should wait until all headers have been processed before beginning to
> prefetch resources" with "User agents MUST wait until all header
> fields have been received and until all Content-Security-Policy header
> fields have been processed before fetching or prefetching resources."
> Note, in particular, the replacement of "should" with "MUST."

I think the requirement is already pretty clearly contained in the previous
sentences ("a response returning the following headers ... MUST have the
same behavior"). I've MUSTed the last sentence for good measure, but I'm
not sure it actually adds anything.

> It would be good to expand the text in the section on <meta> to more
> explicitly call out what can go wrong with using <meta>-specified
> policies. The current text is good in pointing out that content that
> appears before the <meta> element will not be restricted by the policy
> in the <meta> element, but it would be good to explicitly call out the
> specific cases we are aware of, .e.g. "In particular, resources
> fetched or prefetched using Link: HTTP header fields and/or resource
> fetched or prefetched using <link> elements that precede a <meta> CSP
> policy will not be restricted by the policy."

Accepted this more or less verbatim.



Mike West <mkwst@google.com>, @mikewest

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Received on Tuesday, 20 January 2015 10:40:20 UTC

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