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[tor-bugs] #8062 [Tor]: We try to squeeze a two-byte version into a one-byte link_proto

#8062: We try to squeeze a two-byte version into a one-byte link_proto
--------------------+-------------------------------------------------------
 Reporter:  arma    |          Owner:                    
     Type:  defect  |         Status:  new               
 Priority:  normal  |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor     |        Version:                    
 Keywords:          |         Parent:                    
   Points:          |   Actualpoints:                    
--------------------+-------------------------------------------------------
 {{{
   int highest_supported_version = 0;
 ...
     uint16_t v = ntohs(get_uint16(cp));
     if (is_or_protocol_version_known(v) && v > highest_supported_version)
       highest_supported_version = v;
 ...
   chan->conn->link_proto = highest_supported_version;
 }}}

 But
 {{{
   uint8_t link_proto; /**< What protocol version are we using? 0 for
                        * "none negotiated yet." */
 }}}

 So these checks in channel_tls_process_versions_cell():
 {{{
   if (!highest_supported_version) {
 ...
   } else if (highest_supported_version == 1) {
 ...
   } else if (highest_supported_version < 3 &&
              chan->conn->base_.state ==  OR_CONN_STATE_OR_HANDSHAKING_V3)
 {
 ...
   } else if (highest_supported_version != 2 &&
              chan->conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V2) {
 }}}
 can all be bypassed by sending 0x0101 rather than 0x0001, etc.

 Reported by bob from irc. He says there are triggerable asserts, but he
 didn't clarify which one.

 See also #8059 for a nearby bug.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/8062>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
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