Commit 2e071322 authored by Nick Mathewson's avatar Nick Mathewson 🦞
Browse files

r13252@catbus: nickm | 2007-06-04 18:57:21 -0400 

 Code to check signatures on consensus directories.


svn:r10492
parent 8b0e6a44

doc/TODO

+1 −1
Original line number Diff line number Diff line
@@ -79,7 +79,7 @@ Things we'd like to do in 0.2.0.x: 
        o Code to generate votes

        o Code to generate consensus from a list of votes

        - Add a signature to a consensus.

        - Code to check signatures on a consensus

        o Code to check signatures on a consensus

        - Push/pull documents as appropriate.

        o Have clients know which authorities are v3 authorities, and what

          their keys are.

src/or/dirvote.c

+62 −0
Original line number Diff line number Diff line
@@ -293,6 +293,7 @@ networkstatus_compute_consensus(smartlist_t *votes, 
    int j;

    SMARTLIST_FOREACH(votes, networkstatus_vote_t *, v,

    {

      tor_assert(v->is_vote);

      smartlist_add(va_times, &v->valid_after);

      smartlist_add(fu_times, &v->fresh_until);

      smartlist_add(vu_times, &v->valid_until);
@@ -629,3 +630,64 @@ networkstatus_compute_consensus(smartlist_t *votes, 
  return result;

}



/** DOCDOC */

int

networkstatus_check_consensus_signature(networkstatus_vote_t *consensus)

{

  int n_good = 0;

  int n_missing_key = 0;

  int n_bad = 0;

  int n_unknown = 0;



  tor_assert(! consensus->is_vote);



  SMARTLIST_FOREACH(consensus->voters, networkstatus_voter_info_t *, voter,

  {

    trusted_dir_server_t *ds =

      trusteddirserver_get_by_v3_auth_digest(voter->identity_digest);

    if (!ds) {

      ++n_unknown;

      continue;

    }

    if (voter->pending_signature) {

      char d[DIGEST_LEN];

      char *signed_digest;

      size_t signed_digest_len;

      tor_assert(!voter->good_signature && !voter->bad_signature);

      if (!ds->v3_cert) {

        ++n_missing_key;

        continue;

      }

      /*XXXX020 check return*/

      crypto_pk_get_digest(ds->v3_cert->signing_key, d);

      if (memcmp(voter->signing_key_digest, d, DIGEST_LEN)) {

        ++n_missing_key;

        continue;

      }

      signed_digest_len = crypto_pk_keysize(ds->v3_cert->signing_key);

      signed_digest = tor_malloc(signed_digest_len);

      if (crypto_pk_public_checksig(ds->v3_cert->signing_key,

                                signed_digest,

                                voter->pending_signature,

                                voter->pending_signature_len) != DIGEST_LEN ||

          memcmp(signed_digest, consensus->networkstatus_digest, DIGEST_LEN)) {

        log_warn(LD_DIR, "Got a bad signature."); /*XXXX020 say more*/

        voter->bad_signature = 1;

      } else {

        voter->good_signature = 1;

      }

      tor_free(voter->pending_signature);

    }

    if (voter->good_signature)

      ++n_good;

    else if (voter->bad_signature)

      ++n_bad;

    else

      tor_assert(0);

  });



  /* XXXX020 actually use the result. */



  return 0;

}

src/or/or.h

+5 −1
Original line number Diff line number Diff line
@@ -1314,7 +1314,8 @@ typedef struct networkstatus_voter_info_t { 


  char *pending_signature;

  int pending_signature_len;

  int bad_signature;

  unsigned int bad_signature : 1;

  unsigned int good_signature : 1;

} networkstatus_voter_info_t;



/*XXXX020 rename to networkstatus_t once it works. */
@@ -1336,6 +1337,8 @@ typedef struct networkstatus_vote_t { 


  struct authority_cert_t *cert; /* vote only. */



  char networkstatus_digest[DIGEST_LEN];



  smartlist_t *routerstatus_list; /* holds vote_routerstatus_t if is_vote,

                                   * otherwise just routerstatus_t. */

} networkstatus_vote_t;
@@ -2732,6 +2735,7 @@ char *networkstatus_compute_consensus(smartlist_t *votes, 
networkstatus_voter_info_t *networkstatus_get_voter_by_id(

                                       networkstatus_vote_t *vote,

                                       const char *identity);

int networkstatus_check_consensus_signature(networkstatus_vote_t *consensus);



/********************************* dns.c ***************************/

src/or/routerparse.c

+2 −0
Original line number Diff line number Diff line
@@ -1801,6 +1801,7 @@ networkstatus_parse_vote_from_string(const char *s, int is_vote) 
  }



  ns = tor_malloc_zero(sizeof(networkstatus_vote_t));

  memcpy(ns->networkstatus_digest, ns_digest, DIGEST_LEN);



  if (is_vote) {

    const char *end_of_cert = NULL;
@@ -2036,6 +2037,7 @@ networkstatus_parse_vote_from_string(const char *s, int is_vote) 
      if (check_signature_token(ns_digest, tok, ns->cert->signing_key, 0,

                                "network-status vote"))

        goto err;

      v->good_signature = 1;

    } else {

      v->pending_signature = tor_memdup(tok->object_body,

                                        tok->object_size);