[whatwg] updateWithSanitizedHTML (was Re: innerStaticHTML)
whatwg at adambarth.com
Tue Dec 1 07:05:13 PST 2009
2009/12/1 Kornel Lesiński <kornel at geekhood.net>:
>> The WebKit community is considering taking up such an experimental
>> implementation. Here's my current proposal for how this might work:
>> I would appreciate any feedback on the design.
> Whitelist requires developers to know about potential risks of each
> element/property, and that's not obvious to everyone: e.g. one might want to
> allow object/embed (for harmless YouTube videos) without realizing that it
> enables XSS.
That's true. It would be interesting to know how often developers
screw this up with Ruby-on-Rails' version of the API.
> It's also non-obvious that style attribute is XSS risk (via behavior
> property). Higher-level filtering option could allow style attribute, and
> only filter out that property. Current proposal would need another whitelist
> for CSS properties.
Script-in-CSS is subtle enough that it's explicitly blocked (like
> And even whitelist for CSS properties couldn't be used to implement "No
> external access" policy (allow images with data: urls, allow http: links,
> but not http: images). This would be useful for webmails and other places
> where website doesn't want to allow 3rd parties tracking views.
I don't think an no external access policy is worth supporting
explicitly. If it falls out of a general design, that's great, but I
don't think the use case is compelling enough to accept the design
constraints required to support it.
> "No clickjacking" option might be useful as well.
I don't have a clear idea how this would work. Did you have something
different in mind than X-Frame-Options (already supported by WebKit)?
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