Hi All,
Currently the spec says that a rule like "*.example.com" does not match
a request from example.com. The result is that if you want to give
access to anything coming from example.com, including any subdomains,
you'll have to write a rule like:
Content-Access-Control: allow <*.example.com>, <example.com>
And similarly, if you want to deny requests from evil.com you have to do:
Content-Access-Control: deny <*.evil.com>, <evil.com>
I think it would be better if *.example.com also matched example.com.
Pros:
In many cases you can write simpler rules since I'd imagine it's more
likely that you want to deny or grant access to both a domain and its
subdomains, than that you just want one of the two.
There's no longer a risk that someone will think that *.example.com does
match example.com.
Cons:
There's a risk that someone will think that *.example.com does not match
example.com.
I actually think that the consequences of misunderstanding is smaller in
the latter case. Lets example the possible misunderstandings under the
two algorithms:
== Current algorithm, *.example.com does not match example.com ==
Author uses the rule
Content-Access-Control: allow <*.example.com>
and thinks this grants access to example.com
The consequences aren't very bad, the only thing that will happen is
that when the site example.com is used things will not work. This is
easily detectable and fixed
Author uses the rule
Content-Access-Control: deny <*.example.com>
and thinks this denies access to example.com
The consequences are bad. Access is not denied to example.com even
though that was intended.
== Proposed algorithm, *.example.com does match example.com ==
Author uses the rule
Content-Access-Control: allow <*.example.com>
and thinks this does not grant access to example.com
The consequences are somewhat bad, access is granted to example.com even
though that was not intended. However, it is likely that however runs
example.com could simply set up foo.example.com and use that to get
access. In general I can't think of a real-world example where you'd
trust the subdomains of a site, but not the top domain.
Author uses the rule
Content-Access-Control: deny <*.example.com>
and thinks this does not deny access to example.com
The consequences aren't very bad, the only thing that will happen is
that when the site example.com is used things will not work. This is
easily detectable and fixed.
/ Jonas
