[tor-bugs] #2667 [Tor Relay]: Exits should block reentry into the tor network

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#2667: Exits should block reentry into the tor network
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 Reporter:  mikeperry  |          Owner:                    
     Type:  defect     |         Status:  new               
 Priority:  major      |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor Relay  |        Version:                    
 Keywords:             |         Parent:  #2664             
   Points:             |   Actualpoints:                    
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Changes (by nickm):

  * priority:  normal => major
  * milestone:  Tor: unspecified => Tor: 0.2.3.x-final


Comment:

 Given recent upswings in the popularity of DOS attacks, I think we should
 plan to do this one for 0.2.3.  Specifically:

   * Exits should block connections to known Tor ORPorts.
   * Bridges (and relays?) should refuse OR connections from exit IPs.
   * Both of these behaviors should be configured via torrc and on-by-
 default.

 The only implementation challenge here will be doing efficient lookup of
 nodes by address or address:port.  (My intuition is that a linear search
 here will be too expensive.)  We can do that by adding another hashmap to
 node_t.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/2667#comment:5>
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