Re: 'none' in a source list.

fwiw, it looks like Gecko behaves the same way as well

it will honor 'none' only when it's by itself but ignore it if there's
other sources also as a part of the source expression

ignoring 'none' in this case as you suggest makes sense to me

thanks
ian


----- Original Message -----
From: "Mike West" <mkwst@google.com>
To: public-webappsec@w3.org
Cc: "Alex Russell" <slightlyoff@google.com>
Sent: Monday, January 7, 2013 9:59:49 AM
Subject: 'none' in a source list.

Alex Russell brought up an interesting case off-list that I think is
currently under-specified: what do we do when 'none' is included in a
source list?

Currently, we specify "If source list (with leading and trailing
whitespace stripped) is a case insensitive match for the string 'none'
(including the quotation marks), return the empty set." I don't think
we say anything about a hypothetical `script-src 'none'
https://example.com/` or `script-src https://example.com 'none'
https://example.net`.

Alex's suggestion, which I think makes sense, is to explicitly treat
'none' in a source list as a noop. If we think of source lists as
strictly additive, then adding 'none' to the whitelist should have no
effect.

...

Actually, now that I'm typing this, I see that that's more or less
what we do in 3.2.2.1 #3: 'none' doesn't match the source-list
grammar, so it's not included in the list, but simply ignored.

That doesn't match WebKit's implementation, however, so I think it's
worth making sure that we agree that it's the right behavior before I
poke at http://trac.webkit.org/browser/trunk/Source/WebCore/page/ContentSecurityPolicy.cpp#L360

Thanks!

--
Mike West <mkwst@google.com>, Developer Advocate
Google Germany GmbH, Dienerstrasse 12, 80331 M√ľnchen, Germany
Google+: https://mkw.st/+, Twitter: @mikewest, Cell: +49 162 10 255 91

Received on Monday, 7 January 2013 18:14:41 UTC