[tor-talk] tor 0.2.8.5-rc connecting to 18.0.0.1

[Roger Dingledine]

On Fri, Aug 19, 2016 at 04:05:07AM +0100, landers at tutanota.com wrote:
> I'd like to ask why is tor-win32-0.2.8.5-rc.zip and torbrowser-install-6.5a2_en-US.exe connecting to 18.0.0.1 ?
>[...]
> is tor 0.2.8.5-rc binding a socket to 18.0.0.1 ? or is it something else?  if so why is this not on the changelog?
> 
> 
> this was a bug 4 or 5 years ago for mac users, had a ticket and its been solved.
> https://trac.torproject.org/projects/tor/ticket/1827 

Neat! It looks like that behavior is back.

> the simple notion that tor connects to an ip with 18.0.0.1 seems unsettling specially when a old ticket solved the issue
> although it was for mac users, i have never encounter this behavior before when using previous versions of TBB or tor packages in windows.
> 
> the other recent version "torbrowser-install-6.0.3_en-US.exe" (e8ca44a4d73bc0183973e3e7abbbaf546c2a1d2cae3df58b76e929332e02a277) simply
> connects to 127.0.0.1 no other behavior is shown.

Sounds like a regression. A search in the code for "18.0.0.1" led me to
get_interface_address6_via_udp_socket_hack(). Looking at the recent
commits that mention that function we have:
https://trac.torproject.org/projects/tor/ticket/17950
and
https://trac.torproject.org/projects/tor/ticket/17951

The ChangeLog entries are:

  o Minor features (relay, address discovery):
    - Add a family argument to get_interface_addresses_raw() and
      subfunctions to make network interface address interogation more
      efficient. Now Tor can specifically ask for IPv4, IPv6 or both
      types of interfaces from the operating system. Resolves
      ticket 17950.
    - When get_interface_address6_list(.,AF_UNSPEC,.) is called and
      fails to enumerate interface addresses using the platform-specific
      API, have it rely on the UDP socket fallback technique to try and
      find out what IP addresses (both IPv4 and IPv6) our machine has.
      Resolves ticket 17951.

That second one looks very related.

Can you open a new ticket on https://bugs.torproject.org/ pointing to
the original issue (#1827) plus these two new ones? Hopefully teor and
rl1987 will notice and work on a fix.

Thanks,
--Roger