[tor-bugs] #16276 [Onionoo]: bug in onionoo's family set detection

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#16276: bug in onionoo's family set detection
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     Reporter:  cypherpunks  |      Owner:
         Type:  defect       |     Status:  new
     Priority:  major        |  Milestone:
    Component:  Onionoo      |    Version:
   Resolution:               |   Keywords:
Actual Points:               |  Parent ID:
       Points:               |
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Comment (by karsten):

 Wow, this looks like an excellent analysis above.  Sorry for arriving
 late, but it seems you have this pretty much under control.

 Regarding the bug, Onionoo indeed copies whatever relays define in their
 server descriptors to the details document without performing any checks.
 It's only the family parameter that is checked for actually mutual family
 relations.

 As for the fix, let's start with the easy fix, which means fixing the
 documentation.  How about:

 "Array of fingerprints or nicknames of relays in the same family as this
 relay '''as reported by the relay'''.  Omitted if empty or if descriptor
 containing this information cannot be found."

 As long-term fix, let's think about adding separate field
 "effective_family" or similar for the sake of backward compatibility and
 to enable clients to detect misconfigurations.  It's not that making
 backward-incompatible changes wouldn't be possible, but they would require
 a 1-month or better 2-month warning, knowing that some clients won't be
 updated at all in practice.  Happy to do that if necessary, but even
 happier not to.

 The implementation would probably go into `NodeDetailsStatusUpdater`, more
 precisely into phase 3 of the update process there.  Ideally, we would be
 able to remove the related code from `NodeIndexer` and use the results
 from the newly added code.  If anybody wants to start hacking on this,
 please say so here and go ahead.

 Thanks everyone!

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16276#comment:12>
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