[tor-bugs] #6866 [Tor Client]: pathbias_count_first_hop(): Bug: circuitbuild.c:2650

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#6866: pathbias_count_first_hop(): Bug: circuitbuild.c:2650
-----------------------------+----------------------------------------------
 Reporter:  fob              |          Owner:  mikeperry         
     Type:  defect           |         Status:  assigned          
 Priority:  major            |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor Client       |        Version:  Tor: 0.2.3.21-rc  
 Keywords:  MikePerry201209  |         Parent:                    
   Points:                   |   Actualpoints:                    
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Changes (by mikeperry):

  * keywords:  => MikePerry201209
  * owner:  => mikeperry
  * status:  new => assigned


Comment:

 Whee. How is it we're building onehop tunnels with something other than 1
 desired hop, I wonder..

 rransom: The problem we face with this code is that weird codepaths like
 this might be possible to exploit to jack up the counts on either side of
 the accounting and thus either force the user to rotate off their guards,
 or induce them into staying longer with malicious guards. That's why I
 added the LD_BUG loglines on other codepaths. In this case it seemed
 "clear" that we should "never" violate that condition, so I added the
 assert..

 I checked for other asserts using git blame for me. In this code, I only
 added this assert, and a matching one on pathbias_count_success().

 Should I change them to LD_BUG notice logs for 0.2.4.x, and LD_BUG info
 lines for 0.2.3.x? I can also add a tor_fragile_assert() instead, I guess,
 though that seems to always do nothing.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6866#comment:3>
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