[tor-bugs] #16400 [Tor]: Bug: Assertion cp failed in microdescs_parse_from_string at ../src/or/routerparse.c:4168

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#16400: Bug: Assertion cp failed in microdescs_parse_from_string at
../src/or/routerparse.c:4168
-------------------------+-------------------------------------------------
     Reporter:  torkeln  |      Owner:
         Type:  defect   |     Status:  new
     Priority:  major    |  Milestone:
    Component:  Tor      |    Version:  Tor: 0.2.6.9
   Resolution:           |   Keywords:  routerparse.c, assertion,
Actual Points:           |  025-backport 026-backport
       Points:           |  Parent ID:
-------------------------+-------------------------------------------------

Comment (by cypherpunks_backup):

 Then, it should be ready for missed "onion-key" for every md.
 {{{
 --- routerparse.c       2015-04-06 13:30:54.000000000 +0000
 +++ routerparse.c.edit  2015-06-22 17:04:52.489550356 +0000
 @@ -4156,6 +4156,7 @@

    while (s < eos) {
      int okay = 0;
 +    int digest_computed = 0;

      start_of_next_microdesc = find_start_of_next_microdesc(s, eos);
      if (!start_of_next_microdesc)
 @@ -4165,8 +4166,10 @@
      {
        const char *cp = tor_memstr(s, start_of_next_microdesc-s,
                                    "onion-key");
 -      tor_assert(cp);
 -
 +      if (!cp) {
 +        log_fn(LOG_PROTOCOL_WARN, LD_DIR, "Malformed microdescriptor");
 +        goto next;
 +      }
        md->bodylen = start_of_next_microdesc - cp;
        md->saved_location = where;
        if (copy_body)
 @@ -4176,6 +4179,7 @@
        md->off = cp - start;
      }
      crypto_digest256(md->digest, md->body, md->bodylen, DIGEST_SHA256);
 +    digest_computed = 1;

      if (tokenize_string(area, s, start_of_next_microdesc, tokens,
                          microdesc_token_table, flags)) {
 @@ -4243,7 +4247,7 @@

      md = NULL;
    next:
 -    if (! okay && invalid_digests_out) {
 +    if (! okay && invalid_digests_out && digest_computed) {
        smartlist_add(invalid_digests_out,
                      tor_memdup(md->digest, DIGEST256_LEN));
      }
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16400#comment:11>
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