diff options
Diffstat (limited to 'src/feature/dirauth/shared_random_state.c')
| -rw-r--r-- | src/feature/dirauth/shared_random_state.c | 1326 |
1 files changed, 1326 insertions, 0 deletions
diff --git a/src/feature/dirauth/shared_random_state.c b/src/feature/dirauth/shared_random_state.c new file mode 100644 index 0000000000..87ddcc0736 --- /dev/null +++ b/src/feature/dirauth/shared_random_state.c @@ -0,0 +1,1326 @@ +/* Copyright (c) 2016-2018, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file shared_random_state.c + * + * \brief Functions and data structures for the state of the random protocol + * as defined in proposal #250. + **/ + +#define SHARED_RANDOM_STATE_PRIVATE + +#include "or/or.h" +#include "or/config.h" +#include "or/confparse.h" +#include "lib/crypt_ops/crypto_util.h" +#include "or/dirauth/dirvote.h" +#include "or/networkstatus.h" +#include "or/router.h" +#include "or/dirauth/shared_random.h" +#include "or/shared_random_client.h" +#include "or/dirauth/shared_random_state.h" +#include "or/voting_schedule.h" +#include "lib/encoding/confline.h" + +#include "or/or_state_st.h" + +/* Default filename of the shared random state on disk. */ +static const char default_fname[] = "sr-state"; + +/* String representation of a protocol phase. */ +static const char *phase_str[] = { "unknown", "commit", "reveal" }; + +/* Our shared random protocol state. There is only one possible state per + * protocol run so this is the global state which is reset at every run once + * the shared random value has been computed. */ +static sr_state_t *sr_state = NULL; + +/* Representation of our persistent state on disk. The sr_state above + * contains the data parsed from this state. When we save to disk, we + * translate the sr_state to this sr_disk_state. */ +static sr_disk_state_t *sr_disk_state = NULL; + +/* Disk state file keys. */ +static const char dstate_commit_key[] = "Commit"; +static const char dstate_prev_srv_key[] = "SharedRandPreviousValue"; +static const char dstate_cur_srv_key[] = "SharedRandCurrentValue"; + +/** dummy instance of sr_disk_state_t, used for type-checking its + * members with CONF_CHECK_VAR_TYPE. */ +DUMMY_TYPECHECK_INSTANCE(sr_disk_state_t); + +/* These next two are duplicates or near-duplicates from config.c */ +#define VAR(name, conftype, member, initvalue) \ + { name, CONFIG_TYPE_ ## conftype, offsetof(sr_disk_state_t, member), \ + initvalue CONF_TEST_MEMBERS(sr_disk_state_t, conftype, member) } +/* As VAR, but the option name and member name are the same. */ +#define V(member, conftype, initvalue) \ + VAR(#member, conftype, member, initvalue) +/* Our persistent state magic number. */ +#define SR_DISK_STATE_MAGIC 0x98AB1254 + +static int +disk_state_validate_cb(void *old_state, void *state, void *default_state, + int from_setconf, char **msg); + +/* Array of variables that are saved to disk as a persistent state. */ +static config_var_t state_vars[] = { + V(Version, UINT, "0"), + V(TorVersion, STRING, NULL), + V(ValidAfter, ISOTIME, NULL), + V(ValidUntil, ISOTIME, NULL), + + V(Commit, LINELIST, NULL), + + V(SharedRandValues, LINELIST_V, NULL), + VAR("SharedRandPreviousValue",LINELIST_S, SharedRandValues, NULL), + VAR("SharedRandCurrentValue", LINELIST_S, SharedRandValues, NULL), + END_OF_CONFIG_VARS +}; + +/* "Extra" variable in the state that receives lines we can't parse. This + * lets us preserve options from versions of Tor newer than us. */ +static config_var_t state_extra_var = { + "__extra", CONFIG_TYPE_LINELIST, + offsetof(sr_disk_state_t, ExtraLines), NULL + CONF_TEST_MEMBERS(sr_disk_state_t, LINELIST, ExtraLines) +}; + +/* Configuration format of sr_disk_state_t. */ +static const config_format_t state_format = { + sizeof(sr_disk_state_t), + SR_DISK_STATE_MAGIC, + offsetof(sr_disk_state_t, magic_), + NULL, + NULL, + state_vars, + disk_state_validate_cb, + &state_extra_var, +}; + +/* Return a string representation of a protocol phase. */ +STATIC const char * +get_phase_str(sr_phase_t phase) +{ + const char *the_string = NULL; + + switch (phase) { + case SR_PHASE_COMMIT: + case SR_PHASE_REVEAL: + the_string = phase_str[phase]; + break; + default: + /* Unknown phase shouldn't be possible. */ + tor_assert(0); + } + + return the_string; +} +/* Return the time we should expire the state file created at <b>now</b>. + * We expire the state file in the beginning of the next protocol run. */ +STATIC time_t +get_state_valid_until_time(time_t now) +{ + int total_rounds = SHARED_RANDOM_N_ROUNDS * SHARED_RANDOM_N_PHASES; + int current_round, voting_interval, rounds_left; + time_t valid_until, beginning_of_current_round; + + voting_interval = get_voting_interval(); + /* Find the time the current round started. */ + beginning_of_current_round = get_start_time_of_current_round(); + + /* Find how many rounds are left till the end of the protocol run */ + current_round = (now / voting_interval) % total_rounds; + rounds_left = total_rounds - current_round; + + /* To find the valid-until time now, take the start time of the current + * round and add to it the time it takes for the leftover rounds to + * complete. */ + valid_until = beginning_of_current_round + (rounds_left * voting_interval); + + { /* Logging */ + char tbuf[ISO_TIME_LEN + 1]; + format_iso_time(tbuf, valid_until); + log_debug(LD_DIR, "SR: Valid until time for state set to %s.", tbuf); + } + + return valid_until; +} + +/* Given the consensus 'valid-after' time, return the protocol phase we should + * be in. */ +STATIC sr_phase_t +get_sr_protocol_phase(time_t valid_after) +{ + /* Shared random protocol has two phases, commit and reveal. */ + int total_periods = SHARED_RANDOM_N_ROUNDS * SHARED_RANDOM_N_PHASES; + int current_slot; + + /* Split time into slots of size 'voting_interval'. See which slot we are + * currently into, and find which phase it corresponds to. */ + current_slot = (valid_after / get_voting_interval()) % total_periods; + + if (current_slot < SHARED_RANDOM_N_ROUNDS) { + return SR_PHASE_COMMIT; + } else { + return SR_PHASE_REVEAL; + } +} + +/* Add the given <b>commit</b> to <b>state</b>. It MUST be a valid commit + * and there shouldn't be a commit from the same authority in the state + * already else verification hasn't been done prior. This takes ownership of + * the commit once in our state. */ +static void +commit_add_to_state(sr_commit_t *commit, sr_state_t *state) +{ + sr_commit_t *saved_commit; + + tor_assert(commit); + tor_assert(state); + + saved_commit = digestmap_set(state->commits, commit->rsa_identity, + commit); + if (saved_commit != NULL) { + /* This means we already have that commit in our state so adding twice + * the same commit is either a code flow error, a corrupted disk state + * or some new unknown issue. */ + log_warn(LD_DIR, "SR: Commit from %s exists in our state while " + "adding it: '%s'", sr_commit_get_rsa_fpr(commit), + commit->encoded_commit); + sr_commit_free(saved_commit); + } +} + +/* Helper: deallocate a commit object. (Used with digestmap_free(), which + * requires a function pointer whose argument is void *). */ +static void +commit_free_(void *p) +{ + sr_commit_free_(p); +} + +#define state_free(val) \ + FREE_AND_NULL(sr_state_t, state_free_, (val)) + +/* Free a state that was allocated with state_new(). */ +static void +state_free_(sr_state_t *state) +{ + if (state == NULL) { + return; + } + tor_free(state->fname); + digestmap_free(state->commits, commit_free_); + tor_free(state->current_srv); + tor_free(state->previous_srv); + tor_free(state); +} + +/* Allocate an sr_state_t object and returns it. If no <b>fname</b>, the + * default file name is used. This function does NOT initialize the state + * timestamp, phase or shared random value. NULL is never returned. */ +static sr_state_t * +state_new(const char *fname, time_t now) +{ + sr_state_t *new_state = tor_malloc_zero(sizeof(*new_state)); + /* If file name is not provided, use default. */ + if (fname == NULL) { + fname = default_fname; + } + new_state->fname = tor_strdup(fname); + new_state->version = SR_PROTO_VERSION; + new_state->commits = digestmap_new(); + new_state->phase = get_sr_protocol_phase(now); + new_state->valid_until = get_state_valid_until_time(now); + return new_state; +} + +/* Set our global state pointer with the one given. */ +static void +state_set(sr_state_t *state) +{ + tor_assert(state); + if (sr_state != NULL) { + state_free(sr_state); + } + sr_state = state; +} + +#define disk_state_free(val) \ + FREE_AND_NULL(sr_disk_state_t, disk_state_free_, (val)) + +/* Free an allocated disk state. */ +static void +disk_state_free_(sr_disk_state_t *state) +{ + if (state == NULL) { + return; + } + config_free(&state_format, state); +} + +/* Allocate a new disk state, initialize it and return it. */ +static sr_disk_state_t * +disk_state_new(time_t now) +{ + sr_disk_state_t *new_state = tor_malloc_zero(sizeof(*new_state)); + + new_state->magic_ = SR_DISK_STATE_MAGIC; + new_state->Version = SR_PROTO_VERSION; + new_state->TorVersion = tor_strdup(get_version()); + new_state->ValidUntil = get_state_valid_until_time(now); + new_state->ValidAfter = now; + + /* Init config format. */ + config_init(&state_format, new_state); + return new_state; +} + +/* Set our global disk state with the given state. */ +static void +disk_state_set(sr_disk_state_t *state) +{ + tor_assert(state); + if (sr_disk_state != NULL) { + disk_state_free(sr_disk_state); + } + sr_disk_state = state; +} + +/* Return -1 if the disk state is invalid (something in there that we can't or + * shouldn't use). Return 0 if everything checks out. */ +static int +disk_state_validate(const sr_disk_state_t *state) +{ + time_t now; + + tor_assert(state); + + /* Do we support the protocol version in the state or is it 0 meaning + * Version wasn't found in the state file or bad anyway ? */ + if (state->Version == 0 || state->Version > SR_PROTO_VERSION) { + goto invalid; + } + + /* If the valid until time is before now, we shouldn't use that state. */ + now = time(NULL); + if (state->ValidUntil < now) { + log_info(LD_DIR, "SR: Disk state has expired. Ignoring it."); + goto invalid; + } + + /* Make sure we don't have a valid after time that is earlier than a valid + * until time which would make things not work well. */ + if (state->ValidAfter >= state->ValidUntil) { + log_info(LD_DIR, "SR: Disk state valid after/until times are invalid."); + goto invalid; + } + + return 0; + + invalid: + return -1; +} + +/* Validate the disk state (NOP for now). */ +static int +disk_state_validate_cb(void *old_state, void *state, void *default_state, + int from_setconf, char **msg) +{ + /* We don't use these; only options do. */ + (void) from_setconf; + (void) default_state; + (void) old_state; + + /* This is called by config_dump which is just before we are about to + * write it to disk. At that point, our global memory state has been + * copied to the disk state so it's fair to assume it's trustable. */ + (void) state; + (void) msg; + return 0; +} + +/* Parse the Commit line(s) in the disk state and translate them to the + * the memory state. Return 0 on success else -1 on error. */ +static int +disk_state_parse_commits(sr_state_t *state, + const sr_disk_state_t *disk_state) +{ + config_line_t *line; + smartlist_t *args = NULL; + + tor_assert(state); + tor_assert(disk_state); + + for (line = disk_state->Commit; line; line = line->next) { + sr_commit_t *commit = NULL; + + /* Extra safety. */ + if (strcasecmp(line->key, dstate_commit_key) || + line->value == NULL) { + /* Ignore any lines that are not commits. */ + tor_fragile_assert(); + continue; + } + args = smartlist_new(); + smartlist_split_string(args, line->value, " ", + SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0); + if (smartlist_len(args) < 3) { + log_warn(LD_BUG, "SR: Too few arguments in Commit Line: %s", + escaped(line->value)); + goto error; + } + commit = sr_parse_commit(args); + if (commit == NULL) { + /* Ignore badly formed commit. It could also be a authority + * fingerprint that we don't know about so it shouldn't be used. */ + smartlist_free(args); + continue; + } + /* We consider parseable commit from our disk state to be valid because + * they need to be in the first place to get in there. */ + commit->valid = 1; + /* Add commit to our state pointer. */ + commit_add_to_state(commit, state); + + SMARTLIST_FOREACH(args, char *, cp, tor_free(cp)); + smartlist_free(args); + } + + return 0; + + error: + SMARTLIST_FOREACH(args, char *, cp, tor_free(cp)); + smartlist_free(args); + return -1; +} + +/* Parse a share random value line from the disk state and save it to dst + * which is an allocated srv object. Return 0 on success else -1. */ +static int +disk_state_parse_srv(const char *value, sr_srv_t *dst) +{ + int ret = -1; + smartlist_t *args; + sr_srv_t *srv; + + tor_assert(value); + tor_assert(dst); + + args = smartlist_new(); + smartlist_split_string(args, value, " ", + SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0); + if (smartlist_len(args) < 2) { + log_warn(LD_BUG, "SR: Too few arguments in shared random value. " + "Line: %s", escaped(value)); + goto error; + } + srv = sr_parse_srv(args); + if (srv == NULL) { + goto error; + } + dst->num_reveals = srv->num_reveals; + memcpy(dst->value, srv->value, sizeof(dst->value)); + tor_free(srv); + ret = 0; + + error: + SMARTLIST_FOREACH(args, char *, s, tor_free(s)); + smartlist_free(args); + return ret; +} + +/* Parse both SharedRandCurrentValue and SharedRandPreviousValue line from + * the state. Return 0 on success else -1. */ +static int +disk_state_parse_sr_values(sr_state_t *state, + const sr_disk_state_t *disk_state) +{ + /* Only one value per type (current or previous) is allowed so we keep + * track of it with these flag. */ + unsigned int seen_previous = 0, seen_current = 0; + config_line_t *line; + sr_srv_t *srv = NULL; + + tor_assert(state); + tor_assert(disk_state); + + for (line = disk_state->SharedRandValues; line; line = line->next) { + if (line->value == NULL) { + continue; + } + srv = tor_malloc_zero(sizeof(*srv)); + if (disk_state_parse_srv(line->value, srv) < 0) { + log_warn(LD_BUG, "SR: Broken current SRV line in state %s", + escaped(line->value)); + goto bad; + } + if (!strcasecmp(line->key, dstate_prev_srv_key)) { + if (seen_previous) { + log_warn(LD_DIR, "SR: Second previous SRV value seen. Bad state"); + goto bad; + } + state->previous_srv = srv; + seen_previous = 1; + } else if (!strcasecmp(line->key, dstate_cur_srv_key)) { + if (seen_current) { + log_warn(LD_DIR, "SR: Second current SRV value seen. Bad state"); + goto bad; + } + state->current_srv = srv; + seen_current = 1; + } else { + /* Unknown key. Ignoring. */ + tor_free(srv); + } + } + + return 0; + bad: + tor_free(srv); + return -1; +} + +/* Parse the given disk state and set a newly allocated state. On success, + * return that state else NULL. */ +static sr_state_t * +disk_state_parse(const sr_disk_state_t *new_disk_state) +{ + sr_state_t *new_state = state_new(default_fname, time(NULL)); + + tor_assert(new_disk_state); + + new_state->version = new_disk_state->Version; + new_state->valid_until = new_disk_state->ValidUntil; + new_state->valid_after = new_disk_state->ValidAfter; + + /* Set our current phase according to the valid-after time in our disk + * state. The disk state we are parsing contains everything for the phase + * starting at valid_after so make sure our phase reflects that. */ + new_state->phase = get_sr_protocol_phase(new_state->valid_after); + + /* Parse the shared random values. */ + if (disk_state_parse_sr_values(new_state, new_disk_state) < 0) { + goto error; + } + /* Parse the commits. */ + if (disk_state_parse_commits(new_state, new_disk_state) < 0) { + goto error; + } + /* Great! This new state contains everything we had on disk. */ + return new_state; + + error: + state_free(new_state); + return NULL; +} + +/* From a valid commit object and an allocated config line, set the line's + * value to the state string representation of a commit. */ +static void +disk_state_put_commit_line(const sr_commit_t *commit, config_line_t *line) +{ + char *reveal_str = NULL; + + tor_assert(commit); + tor_assert(line); + + if (!tor_mem_is_zero(commit->encoded_reveal, + sizeof(commit->encoded_reveal))) { + /* Add extra whitespace so we can format the line correctly. */ + tor_asprintf(&reveal_str, " %s", commit->encoded_reveal); + } + tor_asprintf(&line->value, "%u %s %s %s%s", + SR_PROTO_VERSION, + crypto_digest_algorithm_get_name(commit->alg), + sr_commit_get_rsa_fpr(commit), + commit->encoded_commit, + reveal_str != NULL ? reveal_str : ""); + if (reveal_str != NULL) { + memwipe(reveal_str, 0, strlen(reveal_str)); + tor_free(reveal_str); + } +} + +/* From a valid srv object and an allocated config line, set the line's + * value to the state string representation of a shared random value. */ +static void +disk_state_put_srv_line(const sr_srv_t *srv, config_line_t *line) +{ + char encoded[SR_SRV_VALUE_BASE64_LEN + 1]; + + tor_assert(line); + + /* No SRV value thus don't add the line. This is possible since we might + * not have a current or previous SRV value in our state. */ + if (srv == NULL) { + return; + } + sr_srv_encode(encoded, sizeof(encoded), srv); + tor_asprintf(&line->value, "%" PRIu64 " %s", srv->num_reveals, encoded); +} + +/* Reset disk state that is free allocated memory and zeroed the object. */ +static void +disk_state_reset(void) +{ + /* Free allocated memory */ + config_free_lines(sr_disk_state->Commit); + config_free_lines(sr_disk_state->SharedRandValues); + config_free_lines(sr_disk_state->ExtraLines); + tor_free(sr_disk_state->TorVersion); + + /* Clean up the struct */ + memset(sr_disk_state, 0, sizeof(*sr_disk_state)); + + /* Reset it with useful data */ + sr_disk_state->magic_ = SR_DISK_STATE_MAGIC; + sr_disk_state->TorVersion = tor_strdup(get_version()); +} + +/* Update our disk state based on our global SR state. */ +static void +disk_state_update(void) +{ + config_line_t **next, *line; + + tor_assert(sr_disk_state); + tor_assert(sr_state); + + /* Reset current disk state. */ + disk_state_reset(); + + /* First, update elements that we don't need to do a construction. */ + sr_disk_state->Version = sr_state->version; + sr_disk_state->ValidUntil = sr_state->valid_until; + sr_disk_state->ValidAfter = sr_state->valid_after; + + /* Shared random values. */ + next = &sr_disk_state->SharedRandValues; + if (sr_state->previous_srv != NULL) { + *next = line = tor_malloc_zero(sizeof(config_line_t)); + line->key = tor_strdup(dstate_prev_srv_key); + disk_state_put_srv_line(sr_state->previous_srv, line); + /* Go to the next shared random value. */ + next = &(line->next); + } + if (sr_state->current_srv != NULL) { + *next = line = tor_malloc_zero(sizeof(*line)); + line->key = tor_strdup(dstate_cur_srv_key); + disk_state_put_srv_line(sr_state->current_srv, line); + } + + /* Parse the commits and construct config line(s). */ + next = &sr_disk_state->Commit; + DIGESTMAP_FOREACH(sr_state->commits, key, sr_commit_t *, commit) { + *next = line = tor_malloc_zero(sizeof(*line)); + line->key = tor_strdup(dstate_commit_key); + disk_state_put_commit_line(commit, line); + next = &(line->next); + } DIGESTMAP_FOREACH_END; +} + +/* Load state from disk and put it into our disk state. If the state passes + * validation, our global state will be updated with it. Return 0 on + * success. On error, -EINVAL is returned if the state on disk did contained + * something malformed or is unreadable. -ENOENT is returned indicating that + * the state file is either empty of non existing. */ +static int +disk_state_load_from_disk(void) +{ + int ret; + char *fname; + + fname = get_datadir_fname(default_fname); + ret = disk_state_load_from_disk_impl(fname); + tor_free(fname); + + return ret; +} + +/* Helper for disk_state_load_from_disk(). */ +STATIC int +disk_state_load_from_disk_impl(const char *fname) +{ + int ret; + char *content = NULL; + sr_state_t *parsed_state = NULL; + sr_disk_state_t *disk_state = NULL; + + /* Read content of file so we can parse it. */ + if ((content = read_file_to_str(fname, 0, NULL)) == NULL) { + log_warn(LD_FS, "SR: Unable to read SR state file %s", + escaped(fname)); + ret = -errno; + goto error; + } + + { + config_line_t *lines = NULL; + char *errmsg = NULL; + + /* Every error in this code path will return EINVAL. */ + ret = -EINVAL; + if (config_get_lines(content, &lines, 0) < 0) { + config_free_lines(lines); + goto error; + } + + disk_state = disk_state_new(time(NULL)); + config_assign(&state_format, disk_state, lines, 0, &errmsg); + config_free_lines(lines); + if (errmsg) { + log_warn(LD_DIR, "SR: Reading state error: %s", errmsg); + tor_free(errmsg); + goto error; + } + } + + /* So far so good, we've loaded our state file into our disk state. Let's + * validate it and then parse it. */ + if (disk_state_validate(disk_state) < 0) { + ret = -EINVAL; + goto error; + } + + parsed_state = disk_state_parse(disk_state); + if (parsed_state == NULL) { + ret = -EINVAL; + goto error; + } + state_set(parsed_state); + disk_state_set(disk_state); + tor_free(content); + log_info(LD_DIR, "SR: State loaded successfully from file %s", fname); + return 0; + + error: + disk_state_free(disk_state); + tor_free(content); + return ret; +} + +/* Save the disk state to disk but before that update it from the current + * state so we always have the latest. Return 0 on success else -1. */ +static int +disk_state_save_to_disk(void) +{ + int ret; + char *state, *content = NULL, *fname = NULL; + char tbuf[ISO_TIME_LEN + 1]; + time_t now = time(NULL); + + /* If we didn't have the opportunity to setup an internal disk state, + * don't bother saving something to disk. */ + if (sr_disk_state == NULL) { + ret = 0; + goto done; + } + + /* Make sure that our disk state is up to date with our memory state + * before saving it to disk. */ + disk_state_update(); + state = config_dump(&state_format, NULL, sr_disk_state, 0, 0); + format_local_iso_time(tbuf, now); + tor_asprintf(&content, + "# Tor shared random state file last generated on %s " + "local time\n" + "# Other times below are in UTC\n" + "# Please *do not* edit this file.\n\n%s", + tbuf, state); + tor_free(state); + fname = get_datadir_fname(default_fname); + if (write_str_to_file(fname, content, 0) < 0) { + log_warn(LD_FS, "SR: Unable to write SR state to file %s", fname); + ret = -1; + goto done; + } + ret = 0; + log_debug(LD_DIR, "SR: Saved state to file %s", fname); + + done: + tor_free(fname); + tor_free(content); + return ret; +} + +/* Reset our state to prepare for a new protocol run. Once this returns, all + * commits in the state will be removed and freed. */ +STATIC void +reset_state_for_new_protocol_run(time_t valid_after) +{ + tor_assert(sr_state); + + /* Keep counters in track */ + sr_state->n_reveal_rounds = 0; + sr_state->n_commit_rounds = 0; + sr_state->n_protocol_runs++; + + /* Reset valid-until */ + sr_state->valid_until = get_state_valid_until_time(valid_after); + sr_state->valid_after = valid_after; + + /* We are in a new protocol run so cleanup commits. */ + sr_state_delete_commits(); +} + +/* This is the first round of the new protocol run starting at + * <b>valid_after</b>. Do the necessary housekeeping. */ +STATIC void +new_protocol_run(time_t valid_after) +{ + sr_commit_t *our_commitment = NULL; + + /* Only compute the srv at the end of the reveal phase. */ + if (sr_state->phase == SR_PHASE_REVEAL) { + /* We are about to compute a new shared random value that will be set in + * our state as the current value so rotate values. */ + state_rotate_srv(); + /* Compute the shared randomness value of the day. */ + sr_compute_srv(); + } + + /* Prepare for the new protocol run by reseting the state */ + reset_state_for_new_protocol_run(valid_after); + + /* Do some logging */ + log_info(LD_DIR, "SR: Protocol run #%" PRIu64 " starting!", + sr_state->n_protocol_runs); + + /* Generate fresh commitments for this protocol run */ + our_commitment = sr_generate_our_commit(valid_after, + get_my_v3_authority_cert()); + if (our_commitment) { + /* Add our commitment to our state. In case we are unable to create one + * (highly unlikely), we won't vote for this protocol run since our + * commitment won't be in our state. */ + sr_state_add_commit(our_commitment); + } +} + +/* Return 1 iff the <b>next_phase</b> is a phase transition from the current + * phase that is it's different. */ +STATIC int +is_phase_transition(sr_phase_t next_phase) +{ + return sr_state->phase != next_phase; +} + +/* Helper function: return a commit using the RSA fingerprint of the + * authority or NULL if no such commit is known. */ +static sr_commit_t * +state_query_get_commit(const char *rsa_fpr) +{ + tor_assert(rsa_fpr); + return digestmap_get(sr_state->commits, rsa_fpr); +} + +/* Helper function: This handles the GET state action using an + * <b>obj_type</b> and <b>data</b> needed for the action. */ +static void * +state_query_get_(sr_state_object_t obj_type, const void *data) +{ + void *obj = NULL; + + switch (obj_type) { + case SR_STATE_OBJ_COMMIT: + { + obj = state_query_get_commit(data); + break; + } + case SR_STATE_OBJ_COMMITS: + obj = sr_state->commits; + break; + case SR_STATE_OBJ_CURSRV: + obj = sr_state->current_srv; + break; + case SR_STATE_OBJ_PREVSRV: + obj = sr_state->previous_srv; + break; + case SR_STATE_OBJ_PHASE: + obj = &sr_state->phase; + break; + case SR_STATE_OBJ_VALID_AFTER: + default: + tor_assert(0); + } + return obj; +} + +/* Helper function: This handles the PUT state action using an + * <b>obj_type</b> and <b>data</b> needed for the action. */ +static void +state_query_put_(sr_state_object_t obj_type, void *data) +{ + switch (obj_type) { + case SR_STATE_OBJ_COMMIT: + { + sr_commit_t *commit = data; + tor_assert(commit); + commit_add_to_state(commit, sr_state); + break; + } + case SR_STATE_OBJ_CURSRV: + sr_state->current_srv = (sr_srv_t *) data; + break; + case SR_STATE_OBJ_PREVSRV: + sr_state->previous_srv = (sr_srv_t *) data; + break; + case SR_STATE_OBJ_VALID_AFTER: + sr_state->valid_after = *((time_t *) data); + break; + /* It's not allowed to change the phase nor the full commitments map from + * the state. The phase is decided during a strict process post voting and + * the commits should be put individually. */ + case SR_STATE_OBJ_PHASE: + case SR_STATE_OBJ_COMMITS: + default: + tor_assert(0); + } +} + +/* Helper function: This handles the DEL_ALL state action using an + * <b>obj_type</b> and <b>data</b> needed for the action. */ +static void +state_query_del_all_(sr_state_object_t obj_type) +{ + switch (obj_type) { + case SR_STATE_OBJ_COMMIT: + { + /* We are in a new protocol run so cleanup commitments. */ + DIGESTMAP_FOREACH_MODIFY(sr_state->commits, key, sr_commit_t *, c) { + sr_commit_free(c); + MAP_DEL_CURRENT(key); + } DIGESTMAP_FOREACH_END; + break; + } + /* The following object are _NOT_ suppose to be removed. */ + case SR_STATE_OBJ_CURSRV: + case SR_STATE_OBJ_PREVSRV: + case SR_STATE_OBJ_PHASE: + case SR_STATE_OBJ_COMMITS: + case SR_STATE_OBJ_VALID_AFTER: + default: + tor_assert(0); + } +} + +/* Helper function: This handles the DEL state action using an + * <b>obj_type</b> and <b>data</b> needed for the action. */ +static void +state_query_del_(sr_state_object_t obj_type, void *data) +{ + (void) data; + + switch (obj_type) { + case SR_STATE_OBJ_PREVSRV: + tor_free(sr_state->previous_srv); + break; + case SR_STATE_OBJ_CURSRV: + tor_free(sr_state->current_srv); + break; + case SR_STATE_OBJ_COMMIT: + case SR_STATE_OBJ_COMMITS: + case SR_STATE_OBJ_PHASE: + case SR_STATE_OBJ_VALID_AFTER: + default: + tor_assert(0); + } +} + +/* Query state using an <b>action</b> for an object type <b>obj_type</b>. + * The <b>data</b> pointer needs to point to an object that the action needs + * to use and if anything is required to be returned, it is stored in + * <b>out</b>. + * + * This mechanism exists so we have one single point where we synchronized + * our memory state with our disk state for every actions that changes it. + * We then trigger a write on disk immediately. + * + * This should be the only entry point to our memory state. It's used by all + * our state accessors and should be in the future. */ +static void +state_query(sr_state_action_t action, sr_state_object_t obj_type, + void *data, void **out) +{ + switch (action) { + case SR_STATE_ACTION_GET: + *out = state_query_get_(obj_type, data); + break; + case SR_STATE_ACTION_PUT: + state_query_put_(obj_type, data); + break; + case SR_STATE_ACTION_DEL: + state_query_del_(obj_type, data); + break; + case SR_STATE_ACTION_DEL_ALL: + state_query_del_all_(obj_type); + break; + case SR_STATE_ACTION_SAVE: + /* Only trigger a disk state save. */ + break; + default: + tor_assert(0); + } + + /* If the action actually changes the state, immediately save it to disk. + * The following will sync the state -> disk state and then save it. */ + if (action != SR_STATE_ACTION_GET) { + disk_state_save_to_disk(); + } +} + +/* Delete the current SRV value from the state freeing it and the value is set + * to NULL meaning empty. */ +static void +state_del_current_srv(void) +{ + state_query(SR_STATE_ACTION_DEL, SR_STATE_OBJ_CURSRV, NULL, NULL); +} + +/* Delete the previous SRV value from the state freeing it and the value is + * set to NULL meaning empty. */ +static void +state_del_previous_srv(void) +{ + state_query(SR_STATE_ACTION_DEL, SR_STATE_OBJ_PREVSRV, NULL, NULL); +} + +/* Rotate SRV value by freeing the previous value, assigning the current + * value to the previous one and nullifying the current one. */ +STATIC void +state_rotate_srv(void) +{ + /* First delete previous SRV from the state. Object will be freed. */ + state_del_previous_srv(); + /* Set previous SRV with the current one. */ + sr_state_set_previous_srv(sr_state_get_current_srv()); + /* Nullify the current srv. */ + sr_state_set_current_srv(NULL); +} + +/* Set valid after time in the our state. */ +void +sr_state_set_valid_after(time_t valid_after) +{ + state_query(SR_STATE_ACTION_PUT, SR_STATE_OBJ_VALID_AFTER, + (void *) &valid_after, NULL); +} + +/* Return the phase we are currently in according to our state. */ +sr_phase_t +sr_state_get_phase(void) +{ + void *ptr; + state_query(SR_STATE_ACTION_GET, SR_STATE_OBJ_PHASE, NULL, &ptr); + return *(sr_phase_t *) ptr; +} + +/* Return the previous SRV value from our state. Value CAN be NULL. */ +const sr_srv_t * +sr_state_get_previous_srv(void) +{ + const sr_srv_t *srv; + state_query(SR_STATE_ACTION_GET, SR_STATE_OBJ_PREVSRV, NULL, + (void *) &srv); + return srv; +} + +/* Set the current SRV value from our state. Value CAN be NULL. The srv + * object ownership is transferred to the state object. */ +void +sr_state_set_previous_srv(const sr_srv_t *srv) +{ + state_query(SR_STATE_ACTION_PUT, SR_STATE_OBJ_PREVSRV, (void *) srv, + NULL); +} + +/* Return the current SRV value from our state. Value CAN be NULL. */ +const sr_srv_t * +sr_state_get_current_srv(void) +{ + const sr_srv_t *srv; + state_query(SR_STATE_ACTION_GET, SR_STATE_OBJ_CURSRV, NULL, + (void *) &srv); + return srv; +} + +/* Set the current SRV value from our state. Value CAN be NULL. The srv + * object ownership is transferred to the state object. */ +void +sr_state_set_current_srv(const sr_srv_t *srv) +{ + state_query(SR_STATE_ACTION_PUT, SR_STATE_OBJ_CURSRV, (void *) srv, + NULL); +} + +/* Clean all the SRVs in our state. */ +void +sr_state_clean_srvs(void) +{ + /* Remove SRVs from state. They will be set to NULL as "empty". */ + state_del_previous_srv(); + state_del_current_srv(); +} + +/* Return a pointer to the commits map from our state. CANNOT be NULL. */ +digestmap_t * +sr_state_get_commits(void) +{ + digestmap_t *commits; + state_query(SR_STATE_ACTION_GET, SR_STATE_OBJ_COMMITS, + NULL, (void *) &commits); + tor_assert(commits); + return commits; +} + +/* Update the current SR state as needed for the upcoming voting round at + * <b>valid_after</b>. */ +void +sr_state_update(time_t valid_after) +{ + sr_phase_t next_phase; + + tor_assert(sr_state); + + /* Don't call this function twice in the same voting period. */ + if (valid_after <= sr_state->valid_after) { + log_info(LD_DIR, "SR: Asked to update state twice. Ignoring."); + return; + } + + /* Get phase of upcoming round. */ + next_phase = get_sr_protocol_phase(valid_after); + + /* If we are transitioning to a new protocol phase, prepare the stage. */ + if (is_phase_transition(next_phase)) { + if (next_phase == SR_PHASE_COMMIT) { + /* Going into commit phase means we are starting a new protocol run. */ + new_protocol_run(valid_after); + } + /* Set the new phase for this round */ + sr_state->phase = next_phase; + } else if (sr_state->phase == SR_PHASE_COMMIT && + digestmap_size(sr_state->commits) == 0) { + /* We are _NOT_ in a transition phase so if we are in the commit phase + * and have no commit, generate one. Chances are that we are booting up + * so let's have a commit in our state for the next voting period. */ + sr_commit_t *our_commit = + sr_generate_our_commit(valid_after, get_my_v3_authority_cert()); + if (our_commit) { + /* Add our commitment to our state. In case we are unable to create one + * (highly unlikely), we won't vote for this protocol run since our + * commitment won't be in our state. */ + sr_state_add_commit(our_commit); + } + } + + sr_state_set_valid_after(valid_after); + + /* Count the current round */ + if (sr_state->phase == SR_PHASE_COMMIT) { + /* invariant check: we've not entered reveal phase yet */ + tor_assert(sr_state->n_reveal_rounds == 0); + sr_state->n_commit_rounds++; + } else { + sr_state->n_reveal_rounds++; + } + + { /* Debugging. */ + char tbuf[ISO_TIME_LEN + 1]; + format_iso_time(tbuf, valid_after); + log_info(LD_DIR, "SR: State prepared for upcoming voting period (%s). " + "Upcoming phase is %s (counters: %d commit & %d reveal rounds).", + tbuf, get_phase_str(sr_state->phase), + sr_state->n_commit_rounds, sr_state->n_reveal_rounds); + } +} + +/* Return commit object from the given authority digest <b>rsa_identity</b>. + * Return NULL if not found. */ +sr_commit_t * +sr_state_get_commit(const char *rsa_identity) +{ + sr_commit_t *commit; + + tor_assert(rsa_identity); + + state_query(SR_STATE_ACTION_GET, SR_STATE_OBJ_COMMIT, + (void *) rsa_identity, (void *) &commit); + return commit; +} + +/* Add <b>commit</b> to the permanent state. The commit object ownership is + * transferred to the state so the caller MUST not free it. */ +void +sr_state_add_commit(sr_commit_t *commit) +{ + tor_assert(commit); + + /* Put the commit to the global state. */ + state_query(SR_STATE_ACTION_PUT, SR_STATE_OBJ_COMMIT, + (void *) commit, NULL); + + log_debug(LD_DIR, "SR: Commit from %s has been added to our state.", + sr_commit_get_rsa_fpr(commit)); +} + +/* Remove all commits from our state. */ +void +sr_state_delete_commits(void) +{ + state_query(SR_STATE_ACTION_DEL_ALL, SR_STATE_OBJ_COMMIT, NULL, NULL); +} + +/* Copy the reveal information from <b>commit</b> into <b>saved_commit</b>. + * This <b>saved_commit</b> MUST come from our current SR state. Once modified, + * the disk state is updated. */ +void +sr_state_copy_reveal_info(sr_commit_t *saved_commit, const sr_commit_t *commit) +{ + tor_assert(saved_commit); + tor_assert(commit); + + saved_commit->reveal_ts = commit->reveal_ts; + memcpy(saved_commit->random_number, commit->random_number, + sizeof(saved_commit->random_number)); + + strlcpy(saved_commit->encoded_reveal, commit->encoded_reveal, + sizeof(saved_commit->encoded_reveal)); + state_query(SR_STATE_ACTION_SAVE, 0, NULL, NULL); + log_debug(LD_DIR, "SR: Reveal value learned %s (for commit %s) from %s", + saved_commit->encoded_reveal, saved_commit->encoded_commit, + sr_commit_get_rsa_fpr(saved_commit)); +} + +/* Set the fresh SRV flag from our state. This doesn't need to trigger a + * disk state synchronization so we directly change the state. */ +void +sr_state_set_fresh_srv(void) +{ + sr_state->is_srv_fresh = 1; +} + +/* Unset the fresh SRV flag from our state. This doesn't need to trigger a + * disk state synchronization so we directly change the state. */ +void +sr_state_unset_fresh_srv(void) +{ + sr_state->is_srv_fresh = 0; +} + +/* Return the value of the fresh SRV flag. */ +unsigned int +sr_state_srv_is_fresh(void) +{ + return sr_state->is_srv_fresh; +} + +/* Cleanup and free our disk and memory state. */ +void +sr_state_free_all(void) +{ + state_free(sr_state); + disk_state_free(sr_disk_state); + /* Nullify our global state. */ + sr_state = NULL; + sr_disk_state = NULL; +} + +/* Save our current state in memory to disk. */ +void +sr_state_save(void) +{ + /* Query a SAVE action on our current state so it's synced and saved. */ + state_query(SR_STATE_ACTION_SAVE, 0, NULL, NULL); +} + +/* Return 1 iff the state has been initialized that is it exists in memory. + * Return 0 otherwise. */ +int +sr_state_is_initialized(void) +{ + return sr_state == NULL ? 0 : 1; +} + +/* Initialize the disk and memory state. + * + * If save_to_disk is set to 1, the state is immediately saved to disk after + * creation else it's not thus only kept in memory. + * If read_from_disk is set to 1, we try to load the state from the disk and + * if not found, a new state is created. + * + * Return 0 on success else a negative value on error. */ +int +sr_state_init(int save_to_disk, int read_from_disk) +{ + int ret = -ENOENT; + time_t now = time(NULL); + + /* We shouldn't have those assigned. */ + tor_assert(sr_disk_state == NULL); + tor_assert(sr_state == NULL); + + /* First, try to load the state from disk. */ + if (read_from_disk) { + ret = disk_state_load_from_disk(); + } + + if (ret < 0) { + switch (-ret) { + case EINVAL: + /* We have a state on disk but it contains something we couldn't parse + * or an invalid entry in the state file. Let's remove it since it's + * obviously unusable and replace it by an new fresh state below. */ + case ENOENT: + { + /* No state on disk so allocate our states for the first time. */ + sr_state_t *new_state = state_new(default_fname, now); + sr_disk_state_t *new_disk_state = disk_state_new(now); + state_set(new_state); + /* It's important to set our disk state pointer since the save call + * below uses it to synchronized it with our memory state. */ + disk_state_set(new_disk_state); + /* No entry, let's save our new state to disk. */ + if (save_to_disk && disk_state_save_to_disk() < 0) { + goto error; + } + break; + } + default: + /* Big problem. Not possible. */ + tor_assert(0); + } + } + /* We have a state in memory, let's make sure it's updated for the current + * and next voting round. */ + { + time_t valid_after = voting_schedule_get_next_valid_after_time(); + sr_state_update(valid_after); + } + return 0; + + error: + return -1; +} + +#ifdef TOR_UNIT_TESTS + +/* Set the current phase of the protocol. Used only by unit tests. */ +void +set_sr_phase(sr_phase_t phase) +{ + tor_assert(sr_state); + sr_state->phase = phase; +} + +/* Get the SR state. Used only by unit tests */ +sr_state_t * +get_sr_state(void) +{ + return sr_state; +} + +#endif /* defined(TOR_UNIT_TESTS) */ |