[tor-bugs] #31107 [Core Tor/Tor]: channel: channel_tls_handle_cell() CELL_VERSIONS code reached

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#31107: channel: channel_tls_handle_cell() CELL_VERSIONS code reached
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 Reporter:  dgoulet                              |          Owner:  nickm
     Type:  defect                               |         Status:
                                                 |  accepted
 Priority:  High                                 |      Milestone:  Tor:
                                                 |  0.4.2.x-final
Component:  Core Tor/Tor                         |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  tor-relay, tor-channel 042-must      |  Actual Points:
  029-backport? 035-backport 040-backport        |
  041-backport BugSmashFund                      |
Parent ID:                                       |         Points:
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------

Comment (by nickm):

 Okay, here is a better diagnosis.

 The problem is that cell_command_is_var_length() looks at the link
 protocol version when deciding whether a cell is variable-length.  That's
 cool, but it does mean that CELL_VERSIONS is not necessarily a variable-
 length cell.  So if somebody sends a VERSIONS cell on a v1 connection,
 we'll hit this warning.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/31107#comment:10>
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