[tor-bugs] #6833 [Tor Directory Authority]: Tor authorities don't handle votes with more than 64 known-flags

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#6833: Tor authorities don't handle votes with more than 64 known-flags
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 Reporter:  nickm                    |          Owner:                    
     Type:  defect                   |         Status:  new               
 Priority:  normal                   |      Milestone:  Tor: 0.2.4.x-final
Component:  Tor Directory Authority  |        Version:                    
 Keywords:                           |         Parent:                    
   Points:                           |   Actualpoints:                    
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 When we get more than 64 known-flags in a vote, we try to stuff them all
 in an uint64 anyway, and access them by masking with 1<<flagnum.  That's
 undefined behavior right there.

 For now, authorities should refuse to accept any vote with more than 64
 flags.  (We're not even close to that limit right now.)  Later, we can use
 a bitfield instead or something.

 This is only a vote issue.  Consensus parsing doesn't have this problem,
 since we just look for the flags we recognize when we're parsing a
 consensus.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/6833>
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