Re: [Edbrowse-dev] zip and security

[Kevin Carhart <kevin@carhart.net>]

On Mon, 5 Mar 2018, Dominique Martinet wrote:

> Karl Dahlke wrote on Mon, Mar 05, 2018:
>> He writes a web page with javascript that does an xhr request to
>> zipxd://foo.zip@:@top
>
> I think it's a matter of priority, but now we have javascript working a
> bit better we might soon find time to make it more restricted somehow.
>
> I still think allowing any site to do xhr requests anywhere is not
> something we will want.

I completely agree.  For a long time we've been in a pocket.  It didn't 
matter that much because we didn't have a lot of pages that were getting 
all the way through the several steps of retrieving responseText, going to 
a callback, processing the content, and innerHTML side effects take it 
back to EBML.  (!)  It's very exciting that we started to get this, so 
congratulations, our prize for breaking through is a new tier of robust 
worries..

I could write the same-origin restriction into javascript.  Not that this 
covers it entirely, but at least the default would be strict and we would 
block some opportunists.  Suppose I have just loaded abc.com, and I 
instantiate a new XHRHttpRequest object.  I try to retrieve a page from 
def.com.  Should I intercept this in javascript before it gets to 
fetchHTTP, and fail silently?  Or throw something?






> I started writing a mail about this ages ago (August last year!) and it