[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

Re: [tor-bugs] #20004 [Core Tor/Tor]: prop224: Add a trunnel subdirectory specifically for HS

#20004: prop224: Add a trunnel subdirectory specifically for HS
-----------------------------+------------------------------------
 Reporter:  dgoulet          |          Owner:  dgoulet
     Type:  enhancement      |         Status:  needs_review
 Priority:  Medium           |      Milestone:  Tor: 0.2.9.x-final
Component:  Core Tor/Tor     |        Version:
 Severity:  Normal           |     Resolution:
 Keywords:  tor-hs, prop224  |  Actual Points:  0.5
Parent ID:  #17241           |         Points:  1
 Reviewer:                   |        Sponsor:  SponsorR-must
-----------------------------+------------------------------------
Changes (by asn):

 * status:  needs_revision => needs_review


Comment:

 Another issue with ESTABLISH_INTRO:

 In the spec we say:
 {{{
    The HANDSHAKE_AUTH field contains the MAC of all earlier fields in
    the cell using as its key the shared per-circuit material ("KH")
    generated during the circuit extension protocol; see tor-spec.txt
    section 5.2, "Setting circuit keys". It prevents replays of
    ESTABLISH_INTRO cells.
 }}}

 In this case, `end_mac_data` should be right before the `handshake_mac`
 field and not in the end. Also, there should probably be another `ptr`
 called `end_sig_data` right before the sig. Or do you think the spec is
 wrong?

 Here is how Alex had his pointers, and that's how I have it in my code.
 Let's keep the same ptr position if possible:

 {{{
 struct hs_establish_intro_cell {
   @ptr start_cell;
   u8 auth_key_type;
   u16 auth_key_len;
   u8 auth_key[auth_key_len];
   u8 n_extensions;
   struct extension extensions[n_extensions];
   @ptr end_mac_fields;
   /* Modify if any new handshake types are added */
   union handshake[auth_key_type] {
     2: u8 sha3_256[SHA3_256_MAC_LEN];
     default: fail;
   };
   u16 siglen;
   @ptr end_sig_fields;
   u8 sig[siglen];
 };
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/20004#comment:4>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online
_______________________________________________
tor-bugs mailing list
tor-bugs@xxxxxxxxxxxxxxxxxxxx
https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-bugs