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Re: A Somewhat Critical View of SOP (Same Origin Policy)

From: Harry Halpin <hhalpin@w3.org>
Date: Thu, 24 Sep 2015 14:50:01 -0400
Message-ID: <560445D9.8000304@w3.org>
To: Dave Longley <dlongley@digitalbazaar.com>
CC: public-web-security@w3.org, "public-webappsec@w3.org" <public-webappsec@w3.org>

On 09/24/2015 11:57 AM, Dave Longley wrote:
> On 09/24/2015 01:07 AM, Harry Halpin wrote:
>> On 09/23/2015 11:56 PM, Dave Longley wrote:
>>> As this has degenerated into what I consider flaming, I've removed
>>> others from the CC list and I don't plan on responding further.
>>> On 09/23/2015 09:12 PM, Harry Halpin wrote:
>>>> TL;DR
>>>> As its pretty clear we're just rehashing known problems with
>>>> violating same origin policy and basic crypto key management
>>>> issues, I will now turn my spam filter back on :)
>>> I do agree we're getting no where, but for different reasons.
>>> Accusing someone of positions they don't hold and then telling them
>>> any response will be considered spam isn't a discussion. No wonder
>>> the motivations of others are unclear to you.
>> I apologize if I've misconstrued your position from specs you've
>> written, code you've written, or blog posts.
> Thank you, apology accepted.
> Also, as always, we do plan on updating our specs as time permits.
> Unfortunately, there's typically a lot going on ... all the time.
> Please keep in mind the "credentials-retrospective" post you referenced
> is a draft. Perhaps we should add a section on differentiating
> technologies from how they are spec'd at the protocol level (as I'm sure
> you know, OAuth 2.0 removed signatures from the spec, with much
> controversy and fallout [1][2]) vs. how they are used or could be used
> and augmented in practice. The same treatment should be applied to all
> specs and feedback is welcome.
> 1.
> http://hueniverse.com/2010/09/15/oauth-2-0-without-signatures-is-bad-for-the-web/
> 2. http://hueniverse.com/2012/07/26/oauth-2-0-and-the-road-to-hell/

Great! Then again - let's work on a redesign *from the ground up* if
needs be of the ideas in WebID and Credentials while maintaining SOP and
reasonable security/privacy constraints.

Although OAuth does effectively do signatures today, it has become more
complex. Speaking of Eran, look at his latest blog posts -  it might be
useful to look at Eran's latest redesign of OAuth called Oz that tries a
vast simplification [1]. There's also been very good privacy analysis of
OAuth that notes that some form of mediators could lead to better
anonymity by Danezis et al. [2].

Note that use of OAuth does *not* violate SOP because it asks for and
gets permissions, and the data transfer is done server-to-server.
Client-based sending of personal data has real difficulty in a
multi-device world due to issues of syncing and devices being offline.
However, you can *do* data transfer server-to-server with digital
signatures and anonymizing property. But building from these kind of
OAuth data-flows is probably the way to go, where key material can be
dynamically bound to the session (ala TLS Token Binding) so avoiding
"one key per user" designs. This slide-deck is a good overview [3].

Any re-design of these protocols will not come from a Community Group
alone. While the work of some CGs have been evocative and interesting,
they are not ready for standardization. Instead, a new effort will need
a broad-based coalition that involves leading security experts,
industry, and IETF/W3C. A solution that respects SOP, simplifies current
flows, does not depend (but is ideally compatible with) on legacy
non-Web standards, and offers better privacy/security *would* get uptake.

While this would require *everyone* leaving their comfort zones, that is
something I am interested in working on.


[2] http://www0.cs.ucl.ac.uk/staff/G.Danezis/papers/popets15-brokid.pdf
[3] http://www.ietf.org/proceedings/91/slides/slides-91-uta-2.pdf
Received on Thursday, 24 September 2015 18:50:04 UTC

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