[tor-bugs] #11743 [Tor]: nodelist_add_microdesc: assign md to all appropriate nodes properly

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#11743: nodelist_add_microdesc: assign md to all appropriate nodes properly
-------------------------+---------------------
 Reporter:  cypherpunks  |          Owner:
     Type:  defect       |         Status:  new
 Priority:  normal       |      Milestone:
Component:  Tor          |        Version:
 Keywords:               |  Actual Points:
Parent ID:               |         Points:
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 Auths can to create the same md for two different relays. Because hash
 collision or evil relay. Last one can to announce any onion keys and
 family, without needs any proofs. All parts of code designed with
 assumption one md per many nodes, except nodelist_add_microdesc.

 nodelist_add_microdesc using
 router_get_consensus_status_by_descriptor_digest which cut off digest,
 digestmap_set using SHA1 while md's digest about SHA256.
 nodelist_add_microdesc can't to assign md to all appropriate nodes, and
 only to first with id returned by
 router_get_consensus_status_by_descriptor_digest.

 If evil relay will craft self id specifically then it will break usage of
 victim's relay for any freshly new clients till updated consensus (it's
 about several hours).

 If to keep nodelist_add_microdesc with md per one node then md format need
 to be more unique generated. Unique md can be generated by adding ID of
 relay, it will stop crafted mds. Which way to choose? Need another ticket
 about it?

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/11743>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
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