[webkit-dev] Security problems with CSS shaders (was Re: Starting implementation on W3C Filter Effects)

Adam Barth abarth at webkit.org
Tue Oct 25 10:18:04 PDT 2011

On Tue, Oct 25, 2011 at 10:07 AM, Dean Jackson <dino at apple.com> wrote:
> On 25/10/2011, at 9:49 AM, Adam Barth wrote:
>>> Adam's point in the bug is that any operation that can access colour channels might be able to perform a timing attack. This would include SVG filters operating on HTML content without any hardware acceleration.
>>> For this reason I'm still tempted to suggest the combination of CSS_FILTERS + WEBGL is enough of a switch for ports to disable this, but I'm happy to add another one.
>>> I'm not sure at what point we should take the discussion from this list and onto bugzilla.
>> I don't believe you understand the security issue.  I'd recommend you
>> seek the advice of security experts to help you make this decision.
> OK, I'll make sure CSS Shaders has a separate flag which allows ports to turn it off. But you'll still be susceptible to the same problems with CSS_FILTERS, and with the current implementation of SVG filters that you support.

Thanks.  I'll flag CSS_FILTERS for further security review.


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