On Jan 28, 2011, at 4:10 PM, Tab Atkins Jr. wrote:

> On Fri, Jan 28, 2011 at 4:07 PM, Maciej Stachowiak <m...@apple.com> wrote:
>> On Jan 28, 2011, at 3:44 PM, Adam Barth wrote:
>>> On Fri, Jan 28, 2011 at 3:11 PM, Maciej Stachowiak <m...@apple.com> wrote:
>>>> On Jan 28, 2011, at 3:06 PM, Tab Atkins Jr. wrote:
>>>>> The WOFF font specification requires that browsers apply Same Origin
>>>>> Restrictions (SOR) to WOFF fonts.  So far, Firefox and IE9 follow this
>>>>> requirement, while we and Opera don't.
>>>>> 
>>>>> As far as I know, our lack of SOR is basically an accident; we
>>>>> implemented support for WOFF before this requirement was added, and
>>>>> just haven't gotten around to adding it in yet.
>>>>> 
>>>>> Chrome people seem amenable to applying SOR to WOFF fonts in Chrome.
>>>>> Is it okay to add this across all our webkit ports?
>>>> 
>>>> It's not an accident. It has been our intent to willfully ignore this 
>>>> requirement.
>>> 
>>> What's the long-term plan here?  Are we hoping the other folks will
>>> come around to this point of view eventually?  From a game-theory
>>> point-of-view, it seems likely that the most permissive behavior is
>>> likely to become wide-spread over time.
>> 
>> A number of us at Apple who have followed downloadable fonts are not keen on 
>> adding pseudo-DRM code to WebKit. That's not the way the Web has worked 
>> historically, and there doesn't seem to be a good reason to special-case 
>> fonts. It's true that other people have come to the opposite conclusion, but 
>> there doesn't seem to be much reason to take their point of view.
>> 
>> We also think it's bad to have this requirement in the spec. But we are 
>> willing to ignore the spec if it's not changed, as with other specs that we 
>> think are a bad idea. I don't think we are too concerned with whether other 
>> implementors come around to this idea, since it's unlikely to hurt our 
>> compatibility. We think of it as having an extra feature.
>> 
>> Bottom line: if there's a strong desire to do this for Chrome, please at 
>> least make it switchable so we don't have to enable it for Safari.
> 
> When the webfont discussion started, two years ago on the CSSWG
> mailing list, Safari appeared to be in favor of SOR
> <http://lists.w3.org/Archives/Public/www-style/2008Oct/0185.html>.
> I'm curious to know the reasoning behind the reversal, so I can tell
> if my own support for SOR is wrong-headed.

I think what I said above roughly summarizes at least my own current thinking.

In the earlier discussion you cite, the context was EOT vs. vanilla OTF; WOFF 
itself hadn't been proposed. At the time, it seemed like a reasonable 
compromise to adopt same-origin if it would get everyone else to go with OTF 
and not push EOT on the Web. Microsoft at the time claimed they would never 
support normal OpenType/TrueType fonts, and it seemed useful to break the 
logjam.

Since then, the situation has changed. Web services have popped up which work 
around the licensing issues on regular fonts. IE9 is also gaining support for 
OpenType and TrueType in addition to WOFF. So the reasons for WOFF's creation 
seem weaker than they ever were. If TrueType fonts with no SOR restriction 
don't cause the sky to fall, then neither will WOFF fonts with no SOR 
restriction. We're choosing to support WOFF in Apple's WebKit because it is 
trivial to do so, but we no longer see same-origin restrictions as useful or 
necessary. In fact, in some ways it would be better if WOFF itself would go 
away, since it has no real benefit over other font formats. But it may have too 
much momentum for that at this point.

In addition to this, notwithstanding my 2008-era ill-considered statement, 
using CORS to relax same-origin restrictions on resource embedding doesn't seem 
like a good fit. CORS is designed to work around cases where you can't even 
send the request, and CORS requests are normally sent with no credentials. But 
we can't reasonably make every font request a proper CORS request, including 
sending OPTIONS preflight requests to get permission to send credentials. And 
we don't know the format until after we know the response content type. Looking 
at CORS headers in a response that is not to a CORS request would break the 
CORS model and add needless complexity to a security-sensitive technology. It 
simply  muddies the waters to use a cross-site communication technology for DRM 
purposes instead.

Regards,
Maciej

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