Commit b9cc4cc5 authored by Nick Mathewson's avatar Nick Mathewson 🤹
Browse files

Merge branch 'ticket4631_squashed'

parents 98bf7604 bed3b292

changes/bug4631

0 → 100644
+6 −0
Original line number Diff line number Diff line 
  o Minor bugfixes (directory authorities):

    - Directory authorities reject votes that arrive too late. In particular,

      once an authority has started fetching missing votes, it no longer

      accepts new votes posted by other authorities. This change helps prevent

      a consensus split, where only some authorities have the late vote.

      Fixes bug 4631; bugfix on 0.2.0.5-alpha.

src/feature/dirauth/dirvote.c

+53 −22
Original line number Diff line number Diff line
@@ -2963,7 +2963,7 @@ dirvote_perform_vote(void) 
  if (!contents)

    return -1;



  pending_vote = dirvote_add_vote(contents, &msg, &status);

  pending_vote = dirvote_add_vote(contents, 0, &msg, &status);

  tor_free(contents);

  if (!pending_vote) {

    log_warn(LD_DIR, "Couldn't store my own vote! (I told myself, '%s'.)",
@@ -3119,13 +3119,45 @@ list_v3_auth_ids(void) 
  return keys;

}



/* Check the voter information <b>vi</b>, and  assert that at least one

 * signature is good. Asserts on failure. */

static void

assert_any_sig_good(const networkstatus_voter_info_t *vi)

{

  int any_sig_good = 0;

  SMARTLIST_FOREACH(vi->sigs, document_signature_t *, sig,

                    if (sig->good_signature)

                      any_sig_good = 1);

  tor_assert(any_sig_good);

}



/* Add <b>cert</b> to our list of known authority certificates. */

static void

add_new_cert_if_needed(const struct authority_cert_t *cert)

{

  tor_assert(cert);

  if (!authority_cert_get_by_digests(cert->cache_info.identity_digest,

                                     cert->signing_key_digest)) {

    /* Hey, it's a new cert! */

    trusted_dirs_load_certs_from_string(

                               cert->cache_info.signed_descriptor_body,

                               TRUSTED_DIRS_CERTS_SRC_FROM_VOTE, 1 /*flush*/,

                               NULL);

    if (!authority_cert_get_by_digests(cert->cache_info.identity_digest,

                                       cert->signing_key_digest)) {

      log_warn(LD_BUG, "We added a cert, but still couldn't find it.");

    }

  }

}



/** Called when we have received a networkstatus vote in <b>vote_body</b>.

 * Parse and validate it, and on success store it as a pending vote (which we

 * then return).  Return NULL on failure.  Sets *<b>msg_out</b> and

 * *<b>status_out</b> to an HTTP response and status code.  (V3 authority

 * only) */

pending_vote_t *

dirvote_add_vote(const char *vote_body, const char **msg_out, int *status_out)

dirvote_add_vote(const char *vote_body, time_t time_posted,

                 const char **msg_out, int *status_out)

{

  networkstatus_t *vote;

  networkstatus_voter_info_t *vi;
@@ -3156,13 +3188,7 @@ dirvote_add_vote(const char *vote_body, const char **msg_out, int *status_out) 
  }

  tor_assert(smartlist_len(vote->voters) == 1);

  vi = get_voter(vote);

  {

    int any_sig_good = 0;

    SMARTLIST_FOREACH(vi->sigs, document_signature_t *, sig,

                      if (sig->good_signature)

                        any_sig_good = 1);

    tor_assert(any_sig_good);

  }

  assert_any_sig_good(vi);

  ds = trusteddirserver_get_by_v3_auth_digest(vi->identity_digest);

  if (!ds) {

    char *keys = list_v3_auth_ids();
@@ -3175,19 +3201,7 @@ dirvote_add_vote(const char *vote_body, const char **msg_out, int *status_out) 
    *msg_out = "Vote not from a recognized v3 authority";

    goto err;

  }

  tor_assert(vote->cert);

  if (!authority_cert_get_by_digests(vote->cert->cache_info.identity_digest,

                                     vote->cert->signing_key_digest)) {

    /* Hey, it's a new cert! */

    trusted_dirs_load_certs_from_string(

                               vote->cert->cache_info.signed_descriptor_body,

                               TRUSTED_DIRS_CERTS_SRC_FROM_VOTE, 1 /*flush*/,

                               NULL);

    if (!authority_cert_get_by_digests(vote->cert->cache_info.identity_digest,

                                       vote->cert->signing_key_digest)) {

      log_warn(LD_BUG, "We added a cert, but still couldn't find it.");

    }

  }

  add_new_cert_if_needed(vote->cert);



  /* Is it for the right period? */

  if (vote->valid_after != voting_schedule.interval_starts) {
@@ -3200,6 +3214,23 @@ dirvote_add_vote(const char *vote_body, const char **msg_out, int *status_out) 
    goto err;

  }



  /* Check if we received it, as a post, after the cutoff when we

   * start asking other dir auths for it. If we do, the best plan

   * is to discard it, because using it greatly increases the chances

   * of a split vote for this round (some dir auths got it in time,

   * some didn't). */

  if (time_posted && time_posted > voting_schedule.fetch_missing_votes) {

    char tbuf1[ISO_TIME_LEN+1], tbuf2[ISO_TIME_LEN+1];

    format_iso_time(tbuf1, time_posted);

    format_iso_time(tbuf2, voting_schedule.fetch_missing_votes);

    log_warn(LD_DIR, "Rejecting posted vote from %s received at %s; "

             "our cutoff for received votes is %s. Check your clock, "

             "CPU load, and network load. Also check the authority that "

             "posted the vote.", vi->address, tbuf1, tbuf2);

    *msg_out = "Posted vote received too late, would be dangerous to count it";

    goto err;

  }



  /* Fetch any new router descriptors we just learned about */

  update_consensus_router_descriptor_downloads(time(NULL), 1, vote);

src/feature/dirauth/dirvote.h

+6 −1
Original line number Diff line number Diff line
@@ -94,6 +94,7 @@ void dirvote_dirreq_get_status_vote(const char *url, smartlist_t *items, 


/* Storing signatures and votes functions */

struct pending_vote_t * dirvote_add_vote(const char *vote_body,

                                         time_t time_posted,

                                         const char **msg_out,

                                         int *status_out);

int dirvote_add_signatures(const char *detached_signatures_body,
@@ -142,9 +143,13 @@ dirvote_dirreq_get_status_vote(const char *url, smartlist_t *items, 
}



static inline struct pending_vote_t *

dirvote_add_vote(const char *vote_body, const char **msg_out, int *status_out)

dirvote_add_vote(const char *vote_body,

                 time_t time_posted,

                 const char **msg_out,

                 int *status_out)

{

  (void) vote_body;

  (void) time_posted;

  /* If the dirauth module is disabled, this should NEVER be called else we

   * failed to safeguard the dirauth module. */

  tor_assert_nonfatal_unreached();

src/feature/dircache/dircache.c

+1 −1
Original line number Diff line number Diff line
@@ -1696,7 +1696,7 @@ directory_handle_command_post,(dir_connection_t *conn, const char *headers, 
      !strcmp(url,"/tor/post/vote")) { /* v3 networkstatus vote */

    const char *msg = "OK";

    int status;

    if (dirvote_add_vote(body, &msg, &status)) {

    if (dirvote_add_vote(body, approx_time(), &msg, &status)) {

      write_short_http_response(conn, status, "Vote stored");

    } else {

      tor_assert(msg);

src/feature/dirclient/dirclient.c

+1 −1
Original line number Diff line number Diff line
@@ -2364,7 +2364,7 @@ handle_response_fetch_status_vote(dir_connection_t *conn, 
             conn->base_.port, conn->requested_resource);

    return -1;

  }

  dirvote_add_vote(body, &msg, &st);

  dirvote_add_vote(body, 0, &msg, &st);

  if (st > 299) {

    log_warn(LD_DIR, "Error adding retrieved vote: %s", msg);

  } else {