W3C home > Mailing lists > Public > public-webrtc@w3.org > January 2014

Re: What is missing for building "real" services?

From: Randell Jesup <randell-ietf@jesup.org>
Date: Fri, 10 Jan 2014 20:54:35 -0500
Message-ID: <52D0A45B.8040403@jesup.org>
To: public-webrtc@w3.org
On 1/9/2014 8:03 PM, cowwoc wrote:
> On 09/01/2014 6:28 PM, Randell Jesup wrote:
>> On 1/9/2014 12:39 AM, cowwoc wrote:
>>> Okay, so here is my second attempt at this:
>>>
>>> We should be able to share any part of the display that the 
>>> application does not control. Meaning, the webapp might allow users 
>>> to share the contents of Excel so long as it has no control over 
>>> what gets displayed by Excel. Similarly, it should be allowed to 
>>> share any browser tab so long as it plays within its own host/origin.
>>>
>>> Assuming that co-browsing is a non-goal for now, is the above 
>>> (read-only screen sharing) safe from a security point of view?
>>
>> There are security issues even for read-only sharing.
>>
>> If the application can control an iframe in the shared tab/window, it 
>> could flick up images of private data it normally couldn't access 
>> (even via writing to a canvas) due to cross-origin restrictions. Data 
>> such as bank accounts, private user pages, etc.
>
> As I mentioned in a follow-up post, we would not allow cross-origin 
> requests. Any application that enables screen sharing would not be 
> allowed to issue any requests outside of its origin.

Sorry, that's not the problem - it's not that the webrtc app would send 
the request, it's that the page being shared would have on it a hidden 
iframe that would get triggered to flip up the info.  That's for 
tab/browser-window sharing; if the shared window was a native app 
window, one assumes that wouldn't be the problem - but sharing a browser 
window/tab is a primary usecase.  If you block that, you can support 
some usecases relatively safely, but users will be understandably 
annoyed/pissed/confused.

-- 
Randell Jesup -- rjesup a t mozilla d o t com
Received on Saturday, 11 January 2014 01:55:52 UTC

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