diff options
Diffstat (limited to 'src/or/dirvote.c')
| -rw-r--r-- | src/or/dirvote.c | 215 |
1 files changed, 135 insertions, 80 deletions
diff --git a/src/or/dirvote.c b/src/or/dirvote.c index e6a745612e..fbd112d488 100644 --- a/src/or/dirvote.c +++ b/src/or/dirvote.c @@ -1,6 +1,6 @@ /* Copyright (c) 2001-2004, Roger Dingledine. * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. - * Copyright (c) 2007-2016, The Tor Project, Inc. */ + * Copyright (c) 2007-2017, The Tor Project, Inc. */ /* See LICENSE for licensing information */ #define DIRVOTE_PRIVATE @@ -26,6 +26,39 @@ /** * \file dirvote.c * \brief Functions to compute directory consensus, and schedule voting. + * + * This module is the center of the consensus-voting based directory + * authority system. With this system, a set of authorities first + * publish vote based on their opinions of the network, and then compute + * a consensus from those votes. Each authority signs the consensus, + * and clients trust the consensus if enough known authorities have + * signed it. + * + * The code in this module is only invoked on directory authorities. It's + * responsible for: + * + * <ul> + * <li>Generating this authority's vote networkstatus, based on the + * authority's view of the network as represented in dirserv.c + * <li>Formatting the vote networkstatus objects. + * <li>Generating the microdescriptors that correspond to our own + * vote. + * <li>Sending votes to all the other authorities. + * <li>Trying to fetch missing votes from other authorities. + * <li>Computing the consensus from a set of votes, as well as + * a "detached signature" object for other authorities to fetch. + * <li>Collecting other authorities' signatures on the same consensus, + * until there are enough. + * <li>Publishing the consensus to the reset of the directory system. + * <li>Scheduling all of the above operations. + * </ul> + * + * The main entry points are in dirvote_act(), which handles scheduled + * actions; and dirvote_add_vote() and dirvote_add_signatures(), which + * handle uploaded and downloaded votes and signatures. + * + * (See dir-spec.txt from torspec.git for a complete specification of + * the directory protocol and voting algorithms.) **/ /** A consensus that we have built and are appending signatures to. Once it's @@ -250,11 +283,11 @@ format_networkstatus_vote(crypto_pk_t *private_signing_key, smartlist_add(chunks, rsf); for (h = vrs->microdesc; h; h = h->next) { - smartlist_add(chunks, tor_strdup(h->microdesc_hash_line)); + smartlist_add_strdup(chunks, h->microdesc_hash_line); } } SMARTLIST_FOREACH_END(vrs); - smartlist_add(chunks, tor_strdup("directory-footer\n")); + smartlist_add_strdup(chunks, "directory-footer\n"); /* The digest includes everything up through the space after * directory-signature. (Yuck.) */ @@ -273,7 +306,6 @@ format_networkstatus_vote(crypto_pk_t *private_signing_key, signing_key_fingerprint); } - note_crypto_pk_op(SIGN_DIR); { char *sig = router_get_dirobj_signature(digest, DIGEST_LEN, private_signing_key); @@ -509,8 +541,8 @@ compute_routerstatus_consensus(smartlist_t *votes, int consensus_method, if (cur_n > most_n || (cur && cur_n == most_n && cur->status.published_on > most_published)) { most = cur; - most_n = cur_n; - most_published = cur->status.published_on; + // most_n = cur_n; // unused after this point. + // most_published = cur->status.published_on; // unused after this point. } tor_assert(most); @@ -712,12 +744,12 @@ dirvote_get_intermediate_param_value(const smartlist_t *param_list, } } SMARTLIST_FOREACH_END(k_v_pair); - if (n_found == 1) + if (n_found == 1) { return value; - else if (BUG(n_found > 1)) - return default_val; - else + } else { + tor_assert_nonfatal(n_found == 0); return default_val; + } } /** Minimum number of directory authorities voting for a parameter to @@ -902,7 +934,7 @@ networkstatus_check_weights(int64_t Wgg, int64_t Wgd, int64_t Wmg, * * It returns true if weights could be computed, false otherwise. */ -static int +int networkstatus_compute_bw_weights_v10(smartlist_t *chunks, int64_t G, int64_t M, int64_t E, int64_t D, int64_t T, int64_t weight_scale) @@ -984,7 +1016,7 @@ networkstatus_compute_bw_weights_v10(smartlist_t *chunks, int64_t G, Wgd = weight_scale; } } else { // Subcase b: R+D >= S - casename = "Case 2b1 (Wgg=1, Wmd=Wgd)"; + casename = "Case 2b1 (Wgg=weight_scale, Wmd=Wgd)"; Wee = (weight_scale*(E - G + M))/E; Wed = (weight_scale*(D - 2*E + 4*G - 2*M))/(3*D); Wme = (weight_scale*(G-M))/E; @@ -997,7 +1029,7 @@ networkstatus_compute_bw_weights_v10(smartlist_t *chunks, int64_t G, weight_scale, G, M, E, D, T, 10, 1); if (berr) { - casename = "Case 2b2 (Wgg=1, Wee=1)"; + casename = "Case 2b2 (Wgg=weight_scale, Wee=weight_scale)"; Wgg = weight_scale; Wee = weight_scale; Wed = (weight_scale*(D - 2*E + G + M))/(3*D); @@ -1066,7 +1098,7 @@ networkstatus_compute_bw_weights_v10(smartlist_t *chunks, int64_t G, } else { // Subcase b: S+D >= T/3 // D != 0 because S+D >= T/3 if (G < E) { - casename = "Case 3bg (G scarce, Wgg=1, Wmd == Wed)"; + casename = "Case 3bg (G scarce, Wgg=weight_scale, Wmd == Wed)"; Wgg = weight_scale; Wgd = (weight_scale*(D - 2*G + E + M))/(3*D); Wmg = 0; @@ -1078,7 +1110,7 @@ networkstatus_compute_bw_weights_v10(smartlist_t *chunks, int64_t G, berr = networkstatus_check_weights(Wgg, Wgd, Wmg, Wme, Wmd, Wee, Wed, weight_scale, G, M, E, D, T, 10, 1); } else { // G >= E - casename = "Case 3be (E scarce, Wee=1, Wmd == Wgd)"; + casename = "Case 3be (E scarce, Wee=weight_scale, Wmd == Wgd)"; Wee = weight_scale; Wed = (weight_scale*(D - 2*E + G + M))/(3*D); Wme = 0; @@ -1112,7 +1144,7 @@ networkstatus_compute_bw_weights_v10(smartlist_t *chunks, int64_t G, tor_assert(0 < weight_scale && weight_scale <= INT32_MAX); /* - * Provide Wgm=Wgg, Wmm=1, Wem=Wee, Weg=Wed. May later determine + * Provide Wgm=Wgg, Wmm=weight_scale, Wem=Wee, Weg=Wed. May later determine * that middle nodes need different bandwidth weights for dirport traffic, * or that weird exit policies need special weight, or that bridges * need special weight. @@ -1295,7 +1327,17 @@ compute_nth_protocol_set(int n, int n_voters, const smartlist_t *votes) * value in a newly allocated string. * * Note: this function DOES NOT check whether the votes are from - * recognized authorities. (dirvote_add_vote does that.) */ + * recognized authorities. (dirvote_add_vote does that.) + * + * <strong>WATCH OUT</strong>: You need to think before you change the + * behavior of this function, or of the functions it calls! If some + * authorities compute the consensus with a different algorithm than + * others, they will not reach the same result, and they will not all + * sign the same thing! If you really need to change the algorithm + * here, you should allocate a new "consensus_method" for the new + * behavior, and make the new behavior conditional on a new-enough + * consensus_method. + **/ char * networkstatus_compute_consensus(smartlist_t *votes, int total_authorities, @@ -1314,7 +1356,7 @@ networkstatus_compute_consensus(smartlist_t *votes, smartlist_t *flags; const char *flavor_name; uint32_t max_unmeasured_bw_kb = DEFAULT_MAX_UNMEASURED_BW_KB; - int64_t G=0, M=0, E=0, D=0, T=0; /* For bandwidth weights */ + int64_t G, M, E, D, T; /* For bandwidth weights */ const routerstatus_format_type_t rs_format = flavor == FLAV_NS ? NS_V3_CONSENSUS : NS_V3_CONSENSUS_MICRODESC; char *params = NULL; @@ -1346,6 +1388,16 @@ networkstatus_compute_consensus(smartlist_t *votes, consensus_method = MAX_SUPPORTED_CONSENSUS_METHOD; } + if (consensus_method >= MIN_METHOD_FOR_INIT_BW_WEIGHTS_ONE) { + /* It's smarter to initialize these weights to 1, so that later on, + * we can't accidentally divide by zero. */ + G = M = E = D = 1; + T = 4; + } else { + /* ...but originally, they were set to zero. */ + G = M = E = D = T = 0; + } + /* Compute medians of time-related things, and figure out how many * routers we might need to talk about. */ { @@ -1385,7 +1437,7 @@ networkstatus_compute_consensus(smartlist_t *votes, smartlist_free(sv); /* elements get freed later. */ } SMARTLIST_FOREACH(v->known_flags, const char *, cp, - smartlist_add(flags, tor_strdup(cp))); + smartlist_add_strdup(flags, cp)); } SMARTLIST_FOREACH_END(v); valid_after = median_time(va_times, n_votes); fresh_until = median_time(fu_times, n_votes); @@ -1418,7 +1470,7 @@ networkstatus_compute_consensus(smartlist_t *votes, smartlist_free(combined_client_versions); if (consensus_method >= MIN_METHOD_FOR_ED25519_ID_VOTING) - smartlist_add(flags, tor_strdup("NoEdConsensus")); + smartlist_add_strdup(flags, "NoEdConsensus"); smartlist_sort_strings(flags); smartlist_uniq_strings(flags); @@ -1482,9 +1534,9 @@ networkstatus_compute_consensus(smartlist_t *votes, total_authorities); if (smartlist_len(param_list)) { params = smartlist_join_strings(param_list, " ", 0, NULL); - smartlist_add(chunks, tor_strdup("params ")); + smartlist_add_strdup(chunks, "params "); smartlist_add(chunks, params); - smartlist_add(chunks, tor_strdup("\n")); + smartlist_add_strdup(chunks, "\n"); } if (consensus_method >= MIN_METHOD_FOR_SHARED_RANDOM) { @@ -2071,10 +2123,10 @@ networkstatus_compute_consensus(smartlist_t *votes, smartlist_join_strings(chosen_flags, " ", 0, NULL)); /* Now the version line. */ if (chosen_version) { - smartlist_add(chunks, tor_strdup("\nv ")); - smartlist_add(chunks, tor_strdup(chosen_version)); + smartlist_add_strdup(chunks, "\nv "); + smartlist_add_strdup(chunks, chosen_version); } - smartlist_add(chunks, tor_strdup("\n")); + smartlist_add_strdup(chunks, "\n"); if (chosen_protocol_list && consensus_method >= MIN_METHOD_FOR_RS_PROTOCOLS) { smartlist_add_asprintf(chunks, "pr %s\n", chosen_protocol_list); @@ -2127,7 +2179,7 @@ networkstatus_compute_consensus(smartlist_t *votes, } /* Mark the directory footer region */ - smartlist_add(chunks, tor_strdup("directory-footer\n")); + smartlist_add_strdup(chunks, "directory-footer\n"); { int64_t weight_scale = BW_WEIGHT_SCALE; @@ -2178,7 +2230,7 @@ networkstatus_compute_consensus(smartlist_t *votes, const char *algname = crypto_digest_algorithm_get_name(digest_alg); char *signature; - smartlist_add(chunks, tor_strdup("directory-signature ")); + smartlist_add_strdup(chunks, "directory-signature "); /* Compute the hash of the chunks. */ crypto_digest_smartlist(digest, digest_len, chunks, "", digest_alg); @@ -2205,7 +2257,7 @@ networkstatus_compute_consensus(smartlist_t *votes, smartlist_add(chunks, signature); if (legacy_id_key_digest && legacy_signing_key) { - smartlist_add(chunks, tor_strdup("directory-signature ")); + smartlist_add_strdup(chunks, "directory-signature "); base16_encode(fingerprint, sizeof(fingerprint), legacy_id_key_digest, DIGEST_LEN); crypto_pk_get_fingerprint(legacy_signing_key, @@ -2518,7 +2570,7 @@ networkstatus_format_signatures(networkstatus_t *consensus, base64_encode(buf, sizeof(buf), sig->signature, sig->signature_len, BASE64_ENCODE_MULTILINE); strlcat(buf, "-----END SIGNATURE-----\n", sizeof(buf)); - smartlist_add(elements, tor_strdup(buf)); + smartlist_add_strdup(elements, buf); } SMARTLIST_FOREACH_END(sig); } SMARTLIST_FOREACH_END(v); @@ -2743,48 +2795,10 @@ dirvote_get_start_of_next_interval(time_t now, int interval, int offset) return next; } -/* Using the time <b>now</b>, return the next voting valid-after time. */ -time_t -get_next_valid_after_time(time_t now) -{ - time_t next_valid_after_time; - const or_options_t *options = get_options(); - voting_schedule_t *new_voting_schedule = - get_voting_schedule(options, now, LOG_INFO); - tor_assert(new_voting_schedule); - - next_valid_after_time = new_voting_schedule->interval_starts; - voting_schedule_free(new_voting_schedule); - - return next_valid_after_time; -} - -static voting_schedule_t voting_schedule; - -/** Set voting_schedule to hold the timing for the next vote we should be - * doing. */ -void -dirvote_recalculate_timing(const or_options_t *options, time_t now) -{ - voting_schedule_t *new_voting_schedule; - - if (!authdir_mode_v3(options)) { - return; - } - - /* get the new voting schedule */ - new_voting_schedule = get_voting_schedule(options, now, LOG_NOTICE); - tor_assert(new_voting_schedule); - - /* Fill in the global static struct now */ - memcpy(&voting_schedule, new_voting_schedule, sizeof(voting_schedule)); - voting_schedule_free(new_voting_schedule); -} - /* Populate and return a new voting_schedule_t that can be used to schedule * voting. The object is allocated on the heap and it's the responsibility of * the caller to free it. Can't fail. */ -voting_schedule_t * +static voting_schedule_t * get_voting_schedule(const or_options_t *options, time_t now, int severity) { int interval, vote_delay, dist_delay; @@ -2839,7 +2853,7 @@ get_voting_schedule(const or_options_t *options, time_t now, int severity) /** Frees a voting_schedule_t. This should be used instead of the generic * tor_free. */ -void +static void voting_schedule_free(voting_schedule_t *voting_schedule_to_free) { if (!voting_schedule_to_free) @@ -2847,13 +2861,53 @@ voting_schedule_free(voting_schedule_t *voting_schedule_to_free) tor_free(voting_schedule_to_free); } +static voting_schedule_t voting_schedule; + +/* Using the time <b>now</b>, return the next voting valid-after time. */ +time_t +dirvote_get_next_valid_after_time(void) +{ + /* This is a safe guard in order to make sure that the voting schedule + * static object is at least initialized. Using this function with a zeroed + * voting schedule can lead to bugs. */ + if (tor_mem_is_zero((const char *) &voting_schedule, + sizeof(voting_schedule))) { + dirvote_recalculate_timing(get_options(), time(NULL)); + voting_schedule.created_on_demand = 1; + } + return voting_schedule.interval_starts; +} + +/** Set voting_schedule to hold the timing for the next vote we should be + * doing. All type of tor do that because HS subsystem needs the timing as + * well to function properly. */ +void +dirvote_recalculate_timing(const or_options_t *options, time_t now) +{ + voting_schedule_t *new_voting_schedule; + + /* get the new voting schedule */ + new_voting_schedule = get_voting_schedule(options, now, LOG_INFO); + tor_assert(new_voting_schedule); + + /* Fill in the global static struct now */ + memcpy(&voting_schedule, new_voting_schedule, sizeof(voting_schedule)); + voting_schedule_free(new_voting_schedule); +} + /** Entry point: Take whatever voting actions are pending as of <b>now</b>. */ void dirvote_act(const or_options_t *options, time_t now) { if (!authdir_mode_v3(options)) return; - if (!voting_schedule.voting_starts) { + tor_assert_nonfatal(voting_schedule.voting_starts); + /* If we haven't initialized this object through this codeflow, we need to + * recalculate the timings to match our vote. The reason to do that is if we + * have a voting schedule initialized 1 minute ago, the voting timings might + * not be aligned to what we should expect with "now". This is especially + * true for TestingTorNetwork using smaller timings. */ + if (voting_schedule.created_on_demand) { char *keys = list_v3_auth_ids(); authority_cert_t *c = get_my_v3_authority_cert(); log_notice(LD_DIR, "Scheduling voting. Known authority IDs are %s. " @@ -3628,8 +3682,8 @@ dirvote_add_signatures(const char *detached_signatures_body, "Queuing it for the next consensus.", source); if (!pending_consensus_signature_list) pending_consensus_signature_list = smartlist_new(); - smartlist_add(pending_consensus_signature_list, - tor_strdup(detached_signatures_body)); + smartlist_add_strdup(pending_consensus_signature_list, + detached_signatures_body); *msg = "Signature queued"; return 0; } @@ -3949,14 +4003,15 @@ dirvote_format_all_microdesc_vote_lines(const routerinfo_t *ri, time_t now, while ((ep = entries)) { char buf[128]; vote_microdesc_hash_t *h; - dirvote_format_microdesc_vote_line(buf, sizeof(buf), ep->md, - ep->low, ep->high); - h = tor_malloc_zero(sizeof(vote_microdesc_hash_t)); - h->microdesc_hash_line = tor_strdup(buf); - h->next = result; - result = h; - ep->md->last_listed = now; - smartlist_add(microdescriptors_out, ep->md); + if (dirvote_format_microdesc_vote_line(buf, sizeof(buf), ep->md, + ep->low, ep->high) >= 0) { + h = tor_malloc_zero(sizeof(vote_microdesc_hash_t)); + h->microdesc_hash_line = tor_strdup(buf); + h->next = result; + result = h; + ep->md->last_listed = now; + smartlist_add(microdescriptors_out, ep->md); + } entries = ep->next; tor_free(ep); } |