[tor-bugs] #17901 [Tor]: Tor would bind ControlPort to public ip address if it has no localhost interface

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#17901: Tor would bind ControlPort to public ip address if it has no localhost
interface
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 Reporter:  s7r                        |          Owner:
     Type:  defect                     |         Status:  new
 Priority:  High                       |      Milestone:  Tor:
Component:  Tor                        |  0.2.8.x-final
 Severity:  Major                      |        Version:  Tor: 0.2.7.6
 Keywords:  027-backport 026-backport  |     Resolution:
Parent ID:                             |  Actual Points:
  Sponsor:                             |         Points:
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Comment (by s7r):

 I think we should automatically disable ControlPort, ExtORPort, TransPort
 and DNSPort if we have no `lo` interface (127.0.0.1 localhost address) and
 they are set with just the port number or auto. If the setting for them is
 <pulic IP / NAT IP>:<port> we assume it's wanted and expected to be open
 there and proceed, but with loud warnings that it's a terrible idea. Maybe
 we should require authentication for ControlPort if opened on public / nat
 IP or quit otherwise? Not entirely sure if it's worth it.

 For ORPort and DirPort binding to whatever IP address it sees is fine, we
 shouldn't change the behavior for these two, so whatever fixes we apply
 should be related to `ControlPort` `TransPort` `DNSPort` `ExtORPort` and
 `SocksPort`. Hope I didn't miss anything.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/17901#comment:9>
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