[tor-bugs] #4587 [Tor Client]: Bugs in tor_tls_got_client_hello()

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#4587: Bugs in tor_tls_got_client_hello()
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 Reporter:  Sebastian   |          Owner:                    
     Type:  defect      |         Status:  needs_review      
 Priority:  normal      |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor Client  |        Version:                    
 Keywords:              |         Parent:                    
   Points:              |   Actualpoints:                    
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Comment(by troll_un):

 Replying to [comment:15 troll_un]:
 > Replying to [comment:12 asn]:
 > > Hm, looking at #4594. Do you think we can get the correct count of
 handshakes by only counting them in `SSL3_ST_SR_CLNT_HELLO_A`?
 > For distinguish reneg req only you need another logic (not depends of
 state during callbacks).

 Actually, You could detect parasitic hello instead of try to detect
 correct count of handshakes (in other words all that not a parasitic hello
 will be reneg request).

 You need to remember the ssl->state for each callback and then to compare
 previous state and current state. Working condition could be looks like:
 {{{
  if ((prev == SSL3_ST_SR_CERT_A || prev == SSL3_ST_SR_CERT_B) &&
      curr == SSL3_ST_SR_CLNT_HELLO_C) { /* parasitic hello detected */
 }}}

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/4587#comment:16>
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