Re: [rtcweb] Please require user consent for data channels

[Roman Shpount <[e-mail]>]

Hi Randell,

I do agree with most of your argument regarding fingerprinting and gUM. I
also agree that this is not just the data channel issue and similar
exploits can be created using audio or video connections. Furthermore,
these usage patterns are very difficult to distinguish from legitimate
applications. On the other hand I would argue that all of this exploits do
not matter, since you can get the same information using non webrtc related
HTML functionality.

One thing that I do not agree with is that PeerConnection introduced a
significant new behavior -- routing data over the non-default network
interface. This is something that was not possible before. There is no way
to overwrite default routing with HTTP request or anything similar
generated by the browser. Overwriting default routing would allow creation
of a whole new class of exploits, from determining user other IP addresses
to forcing traffic over unexpected networks and generating expenses for the
 user. My suggestion is that until system wide preferences are exposed via
some other mechanism defined by MIF, web browser should follow the local
policy and do not overwrite local routing metrics by sending ICE requests
over specific interfaces. At the very least, this should only be enabled
via some sort of configuration option which should be disabled by default.
I understand that using only default routes can decrease the chances of
connection, but from my experience* we are talking about less then 0.1% of
all the users.

Also, please note that a lot of software VPNs do allow routing over
secondary gateways. There is nothing fake or unusual about them. For
instance Microsoft default PPTP VPN simply creates a virtual adapter for
the VPN connection and creates a route with lower metric. This virtual
adapter, on the other hand is using the previous default route for PPTP
connection.

* We have deployed a VoIP system with 500K users that used ICE in
combination with TURNs over default route with HTTP connect option. Total
number of users who could not place a call even though they could connect
to the web server was less then 0.1%.
_____________
Roman Shpount