commit 9c9214f2c9f4e9511a2e09238e1cc90d81ae02de
Merge: a9c84bfd3 dfc3e552a
Author: Nick Mathewson <nickm(a)torproject.org>
Date: Tue Mar 12 11:03:37 2019 -0400
Merge remote-tracking branch 'tor-github/pr/776' into maint-0.4.0
changes/bug29706_minimal | 4 +
changes/bug29706_refactor | 4 +
src/feature/dirauth/shared_random.c | 8 +-
src/feature/dirauth/shared_random.h | 2 +-
src/feature/dirauth/shared_random_state.c | 60 ++++++--
src/feature/dirauth/shared_random_state.h | 2 +
src/test/test_shared_random.c | 245 +++++++++++++++++++++++++++---
7 files changed, 290 insertions(+), 35 deletions(-)
diff --cc src/feature/dirauth/shared_random.c
index 34b228325,000000000..137c49800
mode 100644,000000..100644
--- a/src/feature/dirauth/shared_random.c
+++ b/src/feature/dirauth/shared_random.c
@@@ -1,1291 -1,0 +1,1291 @@@
+/* Copyright (c) 2016-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file shared_random.c
+ *
+ * \brief Functions and data structure needed to accomplish the shared
+ * random protocol as defined in proposal #250.
+ *
+ * \details
+ *
+ * This file implements the dirauth-only commit-and-reveal protocol specified
+ * by proposal #250. The protocol has two phases (sr_phase_t): the commitment
+ * phase and the reveal phase (see get_sr_protocol_phase()).
+ *
+ * During the protocol, directory authorities keep state in memory (using
+ * sr_state_t) and in disk (using sr_disk_state_t). The synchronization between
+ * these two data structures happens in disk_state_update() and
+ * disk_state_parse().
+ *
+ * Here is a rough protocol outline:
+ *
+ * 1) In the beginning of the commitment phase, dirauths generate a
+ * commitment/reveal value for the current protocol run (see
+ * new_protocol_run() and sr_generate_our_commit()).
+ *
+ * 2) During voting, dirauths publish their commits in their votes
+ * depending on the current phase. Dirauths also include the two
+ * latest shared random values (SRV) in their votes.
+ * (see sr_get_string_for_vote())
+ *
+ * 3) Upon receiving a commit from a vote, authorities parse it, verify
+ * it, and attempt to save any new commitment or reveal information in
+ * their state file (see extract_shared_random_commits() and
+ * sr_handle_received_commits()). They also parse SRVs from votes to
+ * decide which SRV should be included in the final consensus (see
+ * extract_shared_random_srvs()).
+ *
+ * 3) After voting is done, we count the SRVs we extracted from the votes,
+ * to find the one voted by the majority of dirauths which should be
+ * included in the final consensus (see get_majority_srv_from_votes()).
+ * If an appropriate SRV is found, it is embedded in the consensus (see
+ * sr_get_string_for_consensus()).
+ *
+ * 4) At the end of the reveal phase, dirauths compute a fresh SRV for the
+ * day using the active commits (see sr_compute_srv()). This new SRV
+ * is embedded in the votes as described above.
+ *
+ * Some more notes:
+ *
+ * - To support rebooting authorities and to avoid double voting, each dirauth
+ * saves the current state of the protocol on disk so that it can resume
+ * normally in case of reboot. The disk state (sr_disk_state_t) is managed by
+ * shared_random_state.c:state_query() and we go to extra lengths to ensure
+ * that the state is flushed on disk everytime we receive any useful
+ * information like commits or SRVs.
+ *
+ * - When we receive a commit from a vote, we examine it to see if it's useful
+ * to us and whether it's appropriate to receive it according to the current
+ * phase of the protocol (see should_keep_commit()). If the commit is useful
+ * to us, we save it in our disk state using save_commit_to_state(). When we
+ * receive the reveal information corresponding to a commitment, we verify
+ * that they indeed match using verify_commit_and_reveal().
+ *
+ * - We treat consensuses as the ground truth, so everytime we generate a new
+ * consensus we update our SR state accordingly even if our local view was
+ * different (see sr_act_post_consensus()).
+ *
+ * - After a consensus has been composed, the SR protocol state gets prepared
+ * for the next voting session using sr_state_update(). That function takes
+ * care of housekeeping and also rotates the SRVs and commits in case a new
+ * protocol run is coming up. We also call sr_state_update() on bootup (in
+ * sr_state_init()), to prepare the state for the very first voting session.
+ *
+ * Terminology:
+ *
+ * - "Commitment" is the commitment value of the commit-and-reveal protocol.
+ *
+ * - "Reveal" is the reveal value of the commit-and-reveal protocol.
+ *
+ * - "Commit" is a struct (sr_commit_t) that contains a commitment value and
+ * optionally also a corresponding reveal value.
+ *
+ * - "SRV" is the Shared Random Value that gets generated as the result of the
+ * commit-and-reveal protocol.
+ **/
+
+#define SHARED_RANDOM_PRIVATE
+
+#include "core/or/or.h"
+#include "feature/dirauth/shared_random.h"
+#include "app/config/config.h"
+#include "app/config/confparse.h"
+#include "lib/crypt_ops/crypto_rand.h"
+#include "lib/crypt_ops/crypto_util.h"
+#include "feature/nodelist/networkstatus.h"
+#include "feature/relay/router.h"
+#include "feature/relay/routerkeys.h"
+#include "feature/nodelist/dirlist.h"
+#include "feature/hs_common/shared_random_client.h"
+#include "feature/dirauth/shared_random_state.h"
+#include "feature/dircommon/voting_schedule.h"
+
+#include "feature/dirauth/dirvote.h"
+#include "feature/dirauth/authmode.h"
+
+#include "feature/nodelist/authority_cert_st.h"
+#include "feature/nodelist/networkstatus_st.h"
+
+/* String prefix of shared random values in votes/consensuses. */
+static const char previous_srv_str[] = "shared-rand-previous-value";
+static const char current_srv_str[] = "shared-rand-current-value";
+static const char commit_ns_str[] = "shared-rand-commit";
+static const char sr_flag_ns_str[] = "shared-rand-participate";
+
+/* The value of the consensus param AuthDirNumSRVAgreements found in the
+ * vote. This is set once the consensus creation subsystem requests the
+ * SRV(s) that should be put in the consensus. We use this value to decide
+ * if we keep or not an SRV. */
+static int32_t num_srv_agreements_from_vote;
+
+/* Return a heap allocated copy of the SRV <b>orig</b>. */
- STATIC sr_srv_t *
- srv_dup(const sr_srv_t *orig)
++sr_srv_t *
++sr_srv_dup(const sr_srv_t *orig)
+{
+ sr_srv_t *duplicate = NULL;
+
+ if (!orig) {
+ return NULL;
+ }
+
+ duplicate = tor_malloc_zero(sizeof(sr_srv_t));
+ duplicate->num_reveals = orig->num_reveals;
+ memcpy(duplicate->value, orig->value, sizeof(duplicate->value));
+ return duplicate;
+}
+
+/* Allocate a new commit object and initializing it with <b>rsa_identity</b>
+ * that MUST be provided. The digest algorithm is set to the default one
+ * that is supported. The rest is uninitialized. This never returns NULL. */
+static sr_commit_t *
+commit_new(const char *rsa_identity)
+{
+ sr_commit_t *commit;
+
+ tor_assert(rsa_identity);
+
+ commit = tor_malloc_zero(sizeof(*commit));
+ commit->alg = SR_DIGEST_ALG;
+ memcpy(commit->rsa_identity, rsa_identity, sizeof(commit->rsa_identity));
+ base16_encode(commit->rsa_identity_hex, sizeof(commit->rsa_identity_hex),
+ commit->rsa_identity, sizeof(commit->rsa_identity));
+ return commit;
+}
+
+/* Issue a log message describing <b>commit</b>. */
+static void
+commit_log(const sr_commit_t *commit)
+{
+ tor_assert(commit);
+
+ log_debug(LD_DIR, "SR: Commit from %s", sr_commit_get_rsa_fpr(commit));
+ log_debug(LD_DIR, "SR: Commit: [TS: %" PRIu64 "] [Encoded: %s]",
+ commit->commit_ts, commit->encoded_commit);
+ log_debug(LD_DIR, "SR: Reveal: [TS: %" PRIu64 "] [Encoded: %s]",
+ commit->reveal_ts, safe_str(commit->encoded_reveal));
+}
+
+/* Make sure that the commitment and reveal information in <b>commit</b>
+ * match. If they match return 0, return -1 otherwise. This function MUST be
+ * used everytime we receive a new reveal value. Furthermore, the commit
+ * object MUST have a reveal value and the hash of the reveal value. */
+STATIC int
+verify_commit_and_reveal(const sr_commit_t *commit)
+{
+ tor_assert(commit);
+
+ log_debug(LD_DIR, "SR: Validating commit from authority %s",
+ sr_commit_get_rsa_fpr(commit));
+
+ /* Check that the timestamps match. */
+ if (commit->commit_ts != commit->reveal_ts) {
+ log_warn(LD_BUG, "SR: Commit timestamp %" PRIu64 " doesn't match reveal "
+ "timestamp %" PRIu64, commit->commit_ts,
+ commit->reveal_ts);
+ goto invalid;
+ }
+
+ /* Verify that the hashed_reveal received in the COMMIT message, matches
+ * the reveal we just received. */
+ {
+ /* We first hash the reveal we just received. */
+ char received_hashed_reveal[sizeof(commit->hashed_reveal)];
+
+ /* Only sha3-256 is supported. */
+ if (commit->alg != SR_DIGEST_ALG) {
+ goto invalid;
+ }
+
+ /* Use the invariant length since the encoded reveal variable has an
+ * extra byte for the NUL terminated byte. */
+ if (crypto_digest256(received_hashed_reveal, commit->encoded_reveal,
+ SR_REVEAL_BASE64_LEN, commit->alg) < 0) {
+ /* Unable to digest the reveal blob, this is unlikely. */
+ goto invalid;
+ }
+
+ /* Now compare that with the hashed_reveal we received in COMMIT. */
+ if (fast_memneq(received_hashed_reveal, commit->hashed_reveal,
+ sizeof(received_hashed_reveal))) {
+ log_warn(LD_BUG, "SR: Received reveal value from authority %s "
+ "doesn't match the commit value.",
+ sr_commit_get_rsa_fpr(commit));
+ goto invalid;
+ }
+ }
+
+ return 0;
+ invalid:
+ return -1;
+}
+
+/* Return true iff the commit contains an encoded reveal value. */
+STATIC int
+commit_has_reveal_value(const sr_commit_t *commit)
+{
+ return !tor_mem_is_zero(commit->encoded_reveal,
+ sizeof(commit->encoded_reveal));
+}
+
+/* Parse the encoded commit. The format is:
+ * base64-encode( TIMESTAMP || H(REVEAL) )
+ *
+ * If successfully decoded and parsed, commit is updated and 0 is returned.
+ * On error, return -1. */
+STATIC int
+commit_decode(const char *encoded, sr_commit_t *commit)
+{
+ int decoded_len = 0;
+ size_t offset = 0;
+ char b64_decoded[SR_COMMIT_LEN];
+
+ tor_assert(encoded);
+ tor_assert(commit);
+
+ if (strlen(encoded) > SR_COMMIT_BASE64_LEN) {
+ /* This means that if we base64 decode successfully the reveiced commit,
+ * we'll end up with a bigger decoded commit thus unusable. */
+ goto error;
+ }
+
+ /* Decode our encoded commit. Let's be careful here since _encoded_ is
+ * coming from the network in a dirauth vote so we expect nothing more
+ * than the base64 encoded length of a commit. */
+ decoded_len = base64_decode(b64_decoded, sizeof(b64_decoded),
+ encoded, strlen(encoded));
+ if (decoded_len < 0) {
+ log_warn(LD_BUG, "SR: Commit from authority %s can't be decoded.",
+ sr_commit_get_rsa_fpr(commit));
+ goto error;
+ }
+
+ if (decoded_len != SR_COMMIT_LEN) {
+ log_warn(LD_BUG, "SR: Commit from authority %s decoded length doesn't "
+ "match the expected length (%d vs %u).",
+ sr_commit_get_rsa_fpr(commit), decoded_len,
+ (unsigned)SR_COMMIT_LEN);
+ goto error;
+ }
+
+ /* First is the timestamp (8 bytes). */
+ commit->commit_ts = tor_ntohll(get_uint64(b64_decoded));
+ offset += sizeof(uint64_t);
+ /* Next is hashed reveal. */
+ memcpy(commit->hashed_reveal, b64_decoded + offset,
+ sizeof(commit->hashed_reveal));
+ /* Copy the base64 blob to the commit. Useful for voting. */
+ strlcpy(commit->encoded_commit, encoded, sizeof(commit->encoded_commit));
+
+ return 0;
+
+ error:
+ return -1;
+}
+
+/* Parse the b64 blob at <b>encoded</b> containing reveal information and
+ * store the information in-place in <b>commit</b>. Return 0 on success else
+ * a negative value. */
+STATIC int
+reveal_decode(const char *encoded, sr_commit_t *commit)
+{
+ int decoded_len = 0;
+ char b64_decoded[SR_REVEAL_LEN];
+
+ tor_assert(encoded);
+ tor_assert(commit);
+
+ if (strlen(encoded) > SR_REVEAL_BASE64_LEN) {
+ /* This means that if we base64 decode successfully the received reveal
+ * value, we'll end up with a bigger decoded value thus unusable. */
+ goto error;
+ }
+
+ /* Decode our encoded reveal. Let's be careful here since _encoded_ is
+ * coming from the network in a dirauth vote so we expect nothing more
+ * than the base64 encoded length of our reveal. */
+ decoded_len = base64_decode(b64_decoded, sizeof(b64_decoded),
+ encoded, strlen(encoded));
+ if (decoded_len < 0) {
+ log_warn(LD_BUG, "SR: Reveal from authority %s can't be decoded.",
+ sr_commit_get_rsa_fpr(commit));
+ goto error;
+ }
+
+ if (decoded_len != SR_REVEAL_LEN) {
+ log_warn(LD_BUG, "SR: Reveal from authority %s decoded length is "
+ "doesn't match the expected length (%d vs %u)",
+ sr_commit_get_rsa_fpr(commit), decoded_len,
+ (unsigned)SR_REVEAL_LEN);
+ goto error;
+ }
+
+ commit->reveal_ts = tor_ntohll(get_uint64(b64_decoded));
+ /* Copy the last part, the random value. */
+ memcpy(commit->random_number, b64_decoded + 8,
+ sizeof(commit->random_number));
+ /* Also copy the whole message to use during verification */
+ strlcpy(commit->encoded_reveal, encoded, sizeof(commit->encoded_reveal));
+
+ return 0;
+
+ error:
+ return -1;
+}
+
+/* Encode a reveal element using a given commit object to dst which is a
+ * buffer large enough to put the base64-encoded reveal construction. The
+ * format is as follow:
+ * REVEAL = base64-encode( TIMESTAMP || H(RN) )
+ * Return base64 encoded length on success else a negative value.
+ */
+STATIC int
+reveal_encode(const sr_commit_t *commit, char *dst, size_t len)
+{
+ int ret;
+ size_t offset = 0;
+ char buf[SR_REVEAL_LEN] = {0};
+
+ tor_assert(commit);
+ tor_assert(dst);
+
+ set_uint64(buf, tor_htonll(commit->reveal_ts));
+ offset += sizeof(uint64_t);
+ memcpy(buf + offset, commit->random_number,
+ sizeof(commit->random_number));
+
+ /* Let's clean the buffer and then b64 encode it. */
+ memset(dst, 0, len);
+ ret = base64_encode(dst, len, buf, sizeof(buf), 0);
+ /* Wipe this buffer because it contains our random value. */
+ memwipe(buf, 0, sizeof(buf));
+ return ret;
+}
+
+/* Encode the given commit object to dst which is a buffer large enough to
+ * put the base64-encoded commit. The format is as follow:
+ * COMMIT = base64-encode( TIMESTAMP || H(H(RN)) )
+ * Return base64 encoded length on success else a negative value.
+ */
+STATIC int
+commit_encode(const sr_commit_t *commit, char *dst, size_t len)
+{
+ size_t offset = 0;
+ char buf[SR_COMMIT_LEN] = {0};
+
+ tor_assert(commit);
+ tor_assert(dst);
+
+ /* First is the timestamp (8 bytes). */
+ set_uint64(buf, tor_htonll(commit->commit_ts));
+ offset += sizeof(uint64_t);
+ /* and then the hashed reveal. */
+ memcpy(buf + offset, commit->hashed_reveal,
+ sizeof(commit->hashed_reveal));
+
+ /* Clean the buffer and then b64 encode it. */
+ memset(dst, 0, len);
+ return base64_encode(dst, len, buf, sizeof(buf), 0);
+}
+
+/* Cleanup both our global state and disk state. */
+static void
+sr_cleanup(void)
+{
+ sr_state_free_all();
+}
+
+/* Using <b>commit</b>, return a newly allocated string containing the commit
+ * information that should be used during SRV calculation. It's the caller
+ * responsibility to free the memory. Return NULL if this is not a commit to be
+ * used for SRV calculation. */
+static char *
+get_srv_element_from_commit(const sr_commit_t *commit)
+{
+ char *element;
+ tor_assert(commit);
+
+ if (!commit_has_reveal_value(commit)) {
+ return NULL;
+ }
+
+ tor_asprintf(&element, "%s%s", sr_commit_get_rsa_fpr(commit),
+ commit->encoded_reveal);
+ return element;
+}
+
+/* Return a srv object that is built with the construction:
+ * SRV = SHA3-256("shared-random" | INT_8(reveal_num) |
+ * INT_4(version) | HASHED_REVEALS | previous_SRV)
+ * This function cannot fail. */
+static sr_srv_t *
+generate_srv(const char *hashed_reveals, uint64_t reveal_num,
+ const sr_srv_t *previous_srv)
+{
+ char msg[DIGEST256_LEN + SR_SRV_MSG_LEN] = {0};
+ size_t offset = 0;
+ sr_srv_t *srv;
+
+ tor_assert(hashed_reveals);
+
+ /* Add the invariant token. */
+ memcpy(msg, SR_SRV_TOKEN, SR_SRV_TOKEN_LEN);
+ offset += SR_SRV_TOKEN_LEN;
+ set_uint64(msg + offset, tor_htonll(reveal_num));
+ offset += sizeof(uint64_t);
+ set_uint32(msg + offset, htonl(SR_PROTO_VERSION));
+ offset += sizeof(uint32_t);
+ memcpy(msg + offset, hashed_reveals, DIGEST256_LEN);
+ offset += DIGEST256_LEN;
+ if (previous_srv != NULL) {
+ memcpy(msg + offset, previous_srv->value, sizeof(previous_srv->value));
+ }
+
+ /* Ok we have our message and key for the HMAC computation, allocate our
+ * srv object and do the last step. */
+ srv = tor_malloc_zero(sizeof(*srv));
+ crypto_digest256((char *) srv->value, msg, sizeof(msg), SR_DIGEST_ALG);
+ srv->num_reveals = reveal_num;
+
+ {
+ /* Debugging. */
+ char srv_hash_encoded[SR_SRV_VALUE_BASE64_LEN + 1];
+ sr_srv_encode(srv_hash_encoded, sizeof(srv_hash_encoded), srv);
+ log_info(LD_DIR, "SR: Generated SRV: %s", srv_hash_encoded);
+ }
+ return srv;
+}
+
+/* Compare reveal values and return the result. This should exclusively be
+ * used by smartlist_sort(). */
+static int
+compare_reveal_(const void **_a, const void **_b)
+{
+ const sr_commit_t *a = *_a, *b = *_b;
+ return fast_memcmp(a->hashed_reveal, b->hashed_reveal,
+ sizeof(a->hashed_reveal));
+}
+
+/* Given <b>commit</b> give the line that we should place in our votes.
+ * It's the responsibility of the caller to free the string. */
+static char *
+get_vote_line_from_commit(const sr_commit_t *commit, sr_phase_t phase)
+{
+ char *vote_line = NULL;
+
+ switch (phase) {
+ case SR_PHASE_COMMIT:
+ tor_asprintf(&vote_line, "%s %u %s %s %s\n",
+ commit_ns_str,
+ SR_PROTO_VERSION,
+ crypto_digest_algorithm_get_name(commit->alg),
+ sr_commit_get_rsa_fpr(commit),
+ commit->encoded_commit);
+ break;
+ case SR_PHASE_REVEAL:
+ {
+ /* Send a reveal value for this commit if we have one. */
+ const char *reveal_str = commit->encoded_reveal;
+ if (tor_mem_is_zero(commit->encoded_reveal,
+ sizeof(commit->encoded_reveal))) {
+ reveal_str = "";
+ }
+ tor_asprintf(&vote_line, "%s %u %s %s %s %s\n",
+ commit_ns_str,
+ SR_PROTO_VERSION,
+ crypto_digest_algorithm_get_name(commit->alg),
+ sr_commit_get_rsa_fpr(commit),
+ commit->encoded_commit, reveal_str);
+ break;
+ }
+ default:
+ tor_assert(0);
+ }
+
+ log_debug(LD_DIR, "SR: Commit vote line: %s", vote_line);
+ return vote_line;
+}
+
+/* Return a heap allocated string that contains the given <b>srv</b> string
+ * representation formatted for a networkstatus document using the
+ * <b>key</b> as the start of the line. This doesn't return NULL. */
+static char *
+srv_to_ns_string(const sr_srv_t *srv, const char *key)
+{
+ char *srv_str;
+ char srv_hash_encoded[SR_SRV_VALUE_BASE64_LEN + 1];
+ tor_assert(srv);
+ tor_assert(key);
+
+ sr_srv_encode(srv_hash_encoded, sizeof(srv_hash_encoded), srv);
+ tor_asprintf(&srv_str, "%s %" PRIu64 " %s\n", key,
+ srv->num_reveals, srv_hash_encoded);
+ log_debug(LD_DIR, "SR: Consensus SRV line: %s", srv_str);
+ return srv_str;
+}
+
+/* Given the previous SRV and the current SRV, return a heap allocated
+ * string with their data that could be put in a vote or a consensus. Caller
+ * must free the returned string. Return NULL if no SRVs were provided. */
+static char *
+get_ns_str_from_sr_values(const sr_srv_t *prev_srv, const sr_srv_t *cur_srv)
+{
+ smartlist_t *chunks = NULL;
+ char *srv_str;
+
+ if (!prev_srv && !cur_srv) {
+ return NULL;
+ }
+
+ chunks = smartlist_new();
+
+ if (prev_srv) {
+ char *srv_line = srv_to_ns_string(prev_srv, previous_srv_str);
+ smartlist_add(chunks, srv_line);
+ }
+
+ if (cur_srv) {
+ char *srv_line = srv_to_ns_string(cur_srv, current_srv_str);
+ smartlist_add(chunks, srv_line);
+ }
+
+ /* Join the line(s) here in one string to return. */
+ srv_str = smartlist_join_strings(chunks, "", 0, NULL);
+ SMARTLIST_FOREACH(chunks, char *, s, tor_free(s));
+ smartlist_free(chunks);
+
+ return srv_str;
+}
+
+/* Return 1 iff the two commits have the same commitment values. This
+ * function does not care about reveal values. */
+STATIC int
+commitments_are_the_same(const sr_commit_t *commit_one,
+ const sr_commit_t *commit_two)
+{
+ tor_assert(commit_one);
+ tor_assert(commit_two);
+
+ if (strcmp(commit_one->encoded_commit, commit_two->encoded_commit)) {
+ return 0;
+ }
+ return 1;
+}
+
+/* We just received a commit from the vote of authority with
+ * <b>identity_digest</b>. Return 1 if this commit is authorititative that
+ * is, it belongs to the authority that voted it. Else return 0 if not. */
+STATIC int
+commit_is_authoritative(const sr_commit_t *commit,
+ const char *voter_key)
+{
+ tor_assert(commit);
+ tor_assert(voter_key);
+
+ return fast_memeq(commit->rsa_identity, voter_key,
+ sizeof(commit->rsa_identity));
+}
+
+/* Decide if the newly received <b>commit</b> should be kept depending on
+ * the current phase and state of the protocol. The <b>voter_key</b> is the
+ * RSA identity key fingerprint of the authority's vote from which the
+ * commit comes from. The <b>phase</b> is the phase we should be validating
+ * the commit for. Return 1 if the commit should be added to our state or 0
+ * if not. */
+STATIC int
+should_keep_commit(const sr_commit_t *commit, const char *voter_key,
+ sr_phase_t phase)
+{
+ const sr_commit_t *saved_commit;
+
+ tor_assert(commit);
+ tor_assert(voter_key);
+
+ log_debug(LD_DIR, "SR: Inspecting commit from %s (voter: %s)?",
+ sr_commit_get_rsa_fpr(commit),
+ hex_str(voter_key, DIGEST_LEN));
+
+ /* For a commit to be considered, it needs to be authoritative (it should
+ * be the voter's own commit). */
+ if (!commit_is_authoritative(commit, voter_key)) {
+ log_debug(LD_DIR, "SR: Ignoring non-authoritative commit.");
+ goto ignore;
+ }
+
+ /* Let's make sure, for extra safety, that this fingerprint is known to
+ * us. Even though this comes from a vote, doesn't hurt to be
+ * extracareful. */
+ if (trusteddirserver_get_by_v3_auth_digest(commit->rsa_identity) == NULL) {
+ log_warn(LD_DIR, "SR: Fingerprint %s is not from a recognized "
+ "authority. Discarding commit.",
+ escaped(commit->rsa_identity));
+ goto ignore;
+ }
+
+ /* Check if the authority that voted for <b>commit</b> has already posted
+ * a commit before. */
+ saved_commit = sr_state_get_commit(commit->rsa_identity);
+
+ switch (phase) {
+ case SR_PHASE_COMMIT:
+ /* Already having a commit for an authority so ignore this one. */
+ if (saved_commit) {
+ /* Receiving known commits should happen naturally since commit phase
+ lasts multiple rounds. However if the commitment value changes
+ during commit phase, it might be a bug so log more loudly. */
+ if (!commitments_are_the_same(commit, saved_commit)) {
+ log_info(LD_DIR,
+ "SR: Received altered commit from %s in commit phase.",
+ sr_commit_get_rsa_fpr(commit));
+ } else {
+ log_debug(LD_DIR, "SR: Ignoring known commit during commit phase.");
+ }
+ goto ignore;
+ }
+
+ /* A commit with a reveal value during commitment phase is very wrong. */
+ if (commit_has_reveal_value(commit)) {
+ log_warn(LD_DIR, "SR: Commit from authority %s has a reveal value "
+ "during COMMIT phase. (voter: %s)",
+ sr_commit_get_rsa_fpr(commit),
+ hex_str(voter_key, DIGEST_LEN));
+ goto ignore;
+ }
+ break;
+ case SR_PHASE_REVEAL:
+ /* We are now in reveal phase. We keep a commit if and only if:
+ *
+ * - We have already seen a commit by this auth, AND
+ * - the saved commit has the same commitment value as this one, AND
+ * - the saved commit has no reveal information, AND
+ * - this commit does have reveal information, AND
+ * - the reveal & commit information are matching.
+ *
+ * If all the above are true, then we are interested in this new commit
+ * for its reveal information. */
+
+ if (!saved_commit) {
+ log_debug(LD_DIR, "SR: Ignoring commit first seen in reveal phase.");
+ goto ignore;
+ }
+
+ if (!commitments_are_the_same(commit, saved_commit)) {
+ log_warn(LD_DIR, "SR: Commit from authority %s is different from "
+ "previous commit in our state (voter: %s)",
+ sr_commit_get_rsa_fpr(commit),
+ hex_str(voter_key, DIGEST_LEN));
+ goto ignore;
+ }
+
+ if (commit_has_reveal_value(saved_commit)) {
+ log_debug(LD_DIR, "SR: Ignoring commit with known reveal info.");
+ goto ignore;
+ }
+
+ if (!commit_has_reveal_value(commit)) {
+ log_debug(LD_DIR, "SR: Ignoring commit without reveal value.");
+ goto ignore;
+ }
+
+ if (verify_commit_and_reveal(commit) < 0) {
+ log_warn(LD_BUG, "SR: Commit from authority %s has an invalid "
+ "reveal value. (voter: %s)",
+ sr_commit_get_rsa_fpr(commit),
+ hex_str(voter_key, DIGEST_LEN));
+ goto ignore;
+ }
+ break;
+ default:
+ tor_assert(0);
+ }
+
+ return 1;
+
+ ignore:
+ return 0;
+}
+
+/* We are in reveal phase and we found a valid and verified <b>commit</b> in
+ * a vote that contains reveal values that we could use. Update the commit
+ * we have in our state. Never call this with an unverified commit. */
+STATIC void
+save_commit_during_reveal_phase(const sr_commit_t *commit)
+{
+ sr_commit_t *saved_commit;
+
+ tor_assert(commit);
+
+ /* Get the commit from our state. */
+ saved_commit = sr_state_get_commit(commit->rsa_identity);
+ tor_assert(saved_commit);
+ /* Safety net. They can not be different commitments at this point. */
+ int same_commits = commitments_are_the_same(commit, saved_commit);
+ tor_assert(same_commits);
+
+ /* Copy reveal information to our saved commit. */
+ sr_state_copy_reveal_info(saved_commit, commit);
+}
+
+/* Save <b>commit</b> to our persistent state. Depending on the current
+ * phase, different actions are taken. Steals reference of <b>commit</b>.
+ * The commit object MUST be valid and verified before adding it to the
+ * state. */
+STATIC void
+save_commit_to_state(sr_commit_t *commit)
+{
+ sr_phase_t phase = sr_state_get_phase();
+
+ ASSERT_COMMIT_VALID(commit);
+
+ switch (phase) {
+ case SR_PHASE_COMMIT:
+ /* During commit phase, just save any new authoritative commit */
+ sr_state_add_commit(commit);
+ break;
+ case SR_PHASE_REVEAL:
+ save_commit_during_reveal_phase(commit);
+ sr_commit_free(commit);
+ break;
+ default:
+ tor_assert(0);
+ }
+}
+
+/* Return 1 if we should we keep an SRV voted by <b>n_agreements</b> auths.
+ * Return 0 if we should ignore it. */
+static int
+should_keep_srv(int n_agreements)
+{
+ /* Check if the most popular SRV has reached majority. */
+ int n_voters = get_n_authorities(V3_DIRINFO);
+ int votes_required_for_majority = (n_voters / 2) + 1;
+
+ /* We need at the very least majority to keep a value. */
+ if (n_agreements < votes_required_for_majority) {
+ log_notice(LD_DIR, "SR: SRV didn't reach majority [%d/%d]!",
+ n_agreements, votes_required_for_majority);
+ return 0;
+ }
+
+ /* When we just computed a new SRV, we need to have super majority in order
+ * to keep it. */
+ if (sr_state_srv_is_fresh()) {
+ /* Check if we have super majority for this new SRV value. */
+ if (n_agreements < num_srv_agreements_from_vote) {
+ log_notice(LD_DIR, "SR: New SRV didn't reach agreement [%d/%d]!",
+ n_agreements, num_srv_agreements_from_vote);
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+/* Helper: compare two DIGEST256_LEN digests. */
+static int
+compare_srvs_(const void **_a, const void **_b)
+{
+ const sr_srv_t *a = *_a, *b = *_b;
+ return tor_memcmp(a->value, b->value, sizeof(a->value));
+}
+
+/* Return the most frequent member of the sorted list of DIGEST256_LEN
+ * digests in <b>sl</b> with the count of that most frequent element. */
+static sr_srv_t *
+smartlist_get_most_frequent_srv(const smartlist_t *sl, int *count_out)
+{
+ return smartlist_get_most_frequent_(sl, compare_srvs_, count_out);
+}
+
+/** Compare two SRVs. Used in smartlist sorting. */
+static int
+compare_srv_(const void **_a, const void **_b)
+{
+ const sr_srv_t *a = *_a, *b = *_b;
+ return fast_memcmp(a->value, b->value,
+ sizeof(a->value));
+}
+
+/* Using a list of <b>votes</b>, return the SRV object from them that has
+ * been voted by the majority of dirauths. If <b>current</b> is set, we look
+ * for the current SRV value else the previous one. The returned pointer is
+ * an object located inside a vote. NULL is returned if no appropriate value
+ * could be found. */
+STATIC sr_srv_t *
+get_majority_srv_from_votes(const smartlist_t *votes, int current)
+{
+ int count = 0;
+ sr_srv_t *most_frequent_srv = NULL;
+ sr_srv_t *the_srv = NULL;
+ smartlist_t *srv_list;
+
+ tor_assert(votes);
+
+ srv_list = smartlist_new();
+
+ /* Walk over votes and register any SRVs found. */
+ SMARTLIST_FOREACH_BEGIN(votes, networkstatus_t *, v) {
+ sr_srv_t *srv_tmp = NULL;
+
+ if (!v->sr_info.participate) {
+ /* Ignore vote that do not participate. */
+ continue;
+ }
+ /* Do we want previous or current SRV? */
+ srv_tmp = current ? v->sr_info.current_srv : v->sr_info.previous_srv;
+ if (!srv_tmp) {
+ continue;
+ }
+
+ smartlist_add(srv_list, srv_tmp);
+ } SMARTLIST_FOREACH_END(v);
+
+ smartlist_sort(srv_list, compare_srv_);
+ most_frequent_srv = smartlist_get_most_frequent_srv(srv_list, &count);
+ if (!most_frequent_srv) {
+ goto end;
+ }
+
+ /* Was this SRV voted by enough auths for us to keep it? */
+ if (!should_keep_srv(count)) {
+ goto end;
+ }
+
+ /* We found an SRV that we can use! Habemus SRV! */
+ the_srv = most_frequent_srv;
+
+ {
+ /* Debugging */
+ char encoded[SR_SRV_VALUE_BASE64_LEN + 1];
+ sr_srv_encode(encoded, sizeof(encoded), the_srv);
+ log_debug(LD_DIR, "SR: Chosen SRV by majority: %s (%d votes)", encoded,
+ count);
+ }
+
+ end:
+ /* We do not free any sr_srv_t values, we don't have the ownership. */
+ smartlist_free(srv_list);
+ return the_srv;
+}
+
+/* Free a commit object. */
+void
+sr_commit_free_(sr_commit_t *commit)
+{
+ if (commit == NULL) {
+ return;
+ }
+ /* Make sure we do not leave OUR random number in memory. */
+ memwipe(commit->random_number, 0, sizeof(commit->random_number));
+ tor_free(commit);
+}
+
+/* Generate the commitment/reveal value for the protocol run starting at
+ * <b>timestamp</b>. <b>my_rsa_cert</b> is our authority RSA certificate. */
+sr_commit_t *
+sr_generate_our_commit(time_t timestamp, const authority_cert_t *my_rsa_cert)
+{
+ sr_commit_t *commit = NULL;
+ char digest[DIGEST_LEN];
+
+ tor_assert(my_rsa_cert);
+
+ /* Get our RSA identity fingerprint */
+ if (crypto_pk_get_digest(my_rsa_cert->identity_key, digest) < 0) {
+ goto error;
+ }
+
+ /* New commit with our identity key. */
+ commit = commit_new(digest);
+
+ /* Generate the reveal random value */
+ crypto_strongest_rand(commit->random_number,
+ sizeof(commit->random_number));
+ commit->commit_ts = commit->reveal_ts = timestamp;
+
+ /* Now get the base64 blob that corresponds to our reveal */
+ if (reveal_encode(commit, commit->encoded_reveal,
+ sizeof(commit->encoded_reveal)) < 0) {
+ log_err(LD_DIR, "SR: Unable to encode our reveal value!");
+ goto error;
+ }
+
+ /* Now let's create the commitment */
+ tor_assert(commit->alg == SR_DIGEST_ALG);
+ /* The invariant length is used here since the encoded reveal variable
+ * has an extra byte added for the NULL terminated byte. */
+ if (crypto_digest256(commit->hashed_reveal, commit->encoded_reveal,
+ SR_REVEAL_BASE64_LEN, commit->alg) < 0) {
+ goto error;
+ }
+
+ /* Now get the base64 blob that corresponds to our commit. */
+ if (commit_encode(commit, commit->encoded_commit,
+ sizeof(commit->encoded_commit)) < 0) {
+ log_err(LD_DIR, "SR: Unable to encode our commit value!");
+ goto error;
+ }
+
+ log_debug(LD_DIR, "SR: Generated our commitment:");
+ commit_log(commit);
+ /* Our commit better be valid :). */
+ commit->valid = 1;
+ return commit;
+
+ error:
+ sr_commit_free(commit);
+ return NULL;
+}
+
+/* Compute the shared random value based on the active commits in our state. */
+void
+sr_compute_srv(void)
+{
+ uint64_t reveal_num = 0;
+ char *reveals = NULL;
+ smartlist_t *chunks, *commits;
+ digestmap_t *state_commits;
+
+ /* Computing a shared random value in the commit phase is very wrong. This
+ * should only happen at the very end of the reveal phase when a new
+ * protocol run is about to start. */
+ if (BUG(sr_state_get_phase() != SR_PHASE_REVEAL))
+ return;
+ state_commits = sr_state_get_commits();
+
+ commits = smartlist_new();
+ chunks = smartlist_new();
+
+ /* We must make a list of commit ordered by authority fingerprint in
+ * ascending order as specified by proposal 250. */
+ DIGESTMAP_FOREACH(state_commits, key, sr_commit_t *, c) {
+ /* Extra safety net, make sure we have valid commit before using it. */
+ ASSERT_COMMIT_VALID(c);
+ /* Let's not use a commit from an authority that we don't know. It's
+ * possible that an authority could be removed during a protocol run so
+ * that commit value should never be used in the SRV computation. */
+ if (trusteddirserver_get_by_v3_auth_digest(c->rsa_identity) == NULL) {
+ log_warn(LD_DIR, "SR: Fingerprint %s is not from a recognized "
+ "authority. Discarding commit for the SRV computation.",
+ sr_commit_get_rsa_fpr(c));
+ continue;
+ }
+ /* We consider this commit valid. */
+ smartlist_add(commits, c);
+ } DIGESTMAP_FOREACH_END;
+ smartlist_sort(commits, compare_reveal_);
+
+ /* Now for each commit for that sorted list in ascending order, we'll
+ * build the element for each authority that needs to go into the srv
+ * computation. */
+ SMARTLIST_FOREACH_BEGIN(commits, const sr_commit_t *, c) {
+ char *element = get_srv_element_from_commit(c);
+ if (element) {
+ smartlist_add(chunks, element);
+ reveal_num++;
+ }
+ } SMARTLIST_FOREACH_END(c);
+ smartlist_free(commits);
+
+ {
+ /* Join all reveal values into one giant string that we'll hash so we
+ * can generated our shared random value. */
+ sr_srv_t *current_srv;
+ char hashed_reveals[DIGEST256_LEN];
+ reveals = smartlist_join_strings(chunks, "", 0, NULL);
+ SMARTLIST_FOREACH(chunks, char *, s, tor_free(s));
+ smartlist_free(chunks);
+ if (crypto_digest256(hashed_reveals, reveals, strlen(reveals),
+ SR_DIGEST_ALG) < 0) {
+ goto end;
+ }
+ current_srv = generate_srv(hashed_reveals, reveal_num,
+ sr_state_get_previous_srv());
+ sr_state_set_current_srv(current_srv);
+ /* We have a fresh SRV, flag our state. */
+ sr_state_set_fresh_srv();
+ }
+
+ end:
+ tor_free(reveals);
+}
+
+/* Parse a commit from a vote or from our disk state and return a newly
+ * allocated commit object. NULL is returned on error.
+ *
+ * The commit's data is in <b>args</b> and the order matters very much:
+ * version, algname, RSA fingerprint, commit value[, reveal value]
+ */
+sr_commit_t *
+sr_parse_commit(const smartlist_t *args)
+{
+ uint32_t version;
+ char *value, digest[DIGEST_LEN];
+ digest_algorithm_t alg;
+ const char *rsa_identity_fpr;
+ sr_commit_t *commit = NULL;
+
+ if (smartlist_len(args) < 4) {
+ goto error;
+ }
+
+ /* First is the version number of the SR protocol which indicates at which
+ * version that commit was created. */
+ value = smartlist_get(args, 0);
+ version = (uint32_t) tor_parse_ulong(value, 10, 1, UINT32_MAX, NULL, NULL);
+ if (version > SR_PROTO_VERSION) {
+ log_info(LD_DIR, "SR: Commit version %" PRIu32 " (%s) is not supported.",
+ version, escaped(value));
+ goto error;
+ }
+
+ /* Second is the algorithm. */
+ value = smartlist_get(args, 1);
+ alg = crypto_digest_algorithm_parse_name(value);
+ if (alg != SR_DIGEST_ALG) {
+ log_warn(LD_BUG, "SR: Commit algorithm %s is not recognized.",
+ escaped(value));
+ goto error;
+ }
+
+ /* Third argument is the RSA fingerprint of the auth and turn it into a
+ * digest value. */
+ rsa_identity_fpr = smartlist_get(args, 2);
+ if (base16_decode(digest, DIGEST_LEN, rsa_identity_fpr,
+ HEX_DIGEST_LEN) < 0) {
+ log_warn(LD_DIR, "SR: RSA fingerprint %s not decodable",
+ escaped(rsa_identity_fpr));
+ goto error;
+ }
+
+ /* Allocate commit since we have a valid identity now. */
+ commit = commit_new(digest);
+
+ /* Fourth argument is the commitment value base64-encoded. */
+ value = smartlist_get(args, 3);
+ if (commit_decode(value, commit) < 0) {
+ goto error;
+ }
+
+ /* (Optional) Fifth argument is the revealed value. */
+ if (smartlist_len(args) > 4) {
+ value = smartlist_get(args, 4);
+ if (reveal_decode(value, commit) < 0) {
+ goto error;
+ }
+ }
+
+ return commit;
+
+ error:
+ sr_commit_free(commit);
+ return NULL;
+}
+
+/* Called when we are done parsing a vote by <b>voter_key</b> that might
+ * contain some useful <b>commits</b>. Find if any of them should be kept
+ * and update our state accordingly. Once done, the list of commitments will
+ * be empty. */
+void
+sr_handle_received_commits(smartlist_t *commits, crypto_pk_t *voter_key)
+{
+ char rsa_identity[DIGEST_LEN];
+
+ tor_assert(voter_key);
+
+ /* It's possible that the vote has _NO_ commits. */
+ if (commits == NULL) {
+ return;
+ }
+
+ /* Get the RSA identity fingerprint of this voter */
+ if (crypto_pk_get_digest(voter_key, rsa_identity) < 0) {
+ return;
+ }
+
+ SMARTLIST_FOREACH_BEGIN(commits, sr_commit_t *, commit) {
+ /* We won't need the commit in this list anymore, kept or not. */
+ SMARTLIST_DEL_CURRENT(commits, commit);
+ /* Check if this commit is valid and should be stored in our state. */
+ if (!should_keep_commit(commit, rsa_identity,
+ sr_state_get_phase())) {
+ sr_commit_free(commit);
+ continue;
+ }
+ /* Ok, we have a valid commit now that we are about to put in our state.
+ * so flag it valid from now on. */
+ commit->valid = 1;
+ /* Everything lines up: save this commit to state then! */
+ save_commit_to_state(commit);
+ } SMARTLIST_FOREACH_END(commit);
+}
+
+/* Return a heap-allocated string containing commits that should be put in
+ * the votes. It's the responsibility of the caller to free the string.
+ * This always return a valid string, either empty or with line(s). */
+char *
+sr_get_string_for_vote(void)
+{
+ char *vote_str = NULL;
+ digestmap_t *state_commits;
+ smartlist_t *chunks = smartlist_new();
+ const or_options_t *options = get_options();
+
+ /* Are we participating in the protocol? */
+ if (!options->AuthDirSharedRandomness) {
+ goto end;
+ }
+
+ log_debug(LD_DIR, "SR: Preparing our vote info:");
+
+ /* First line, put in the vote the participation flag. */
+ {
+ char *sr_flag_line;
+ tor_asprintf(&sr_flag_line, "%s\n", sr_flag_ns_str);
+ smartlist_add(chunks, sr_flag_line);
+ }
+
+ /* In our vote we include every commitment in our permanent state. */
+ state_commits = sr_state_get_commits();
+ smartlist_t *state_commit_vote_lines = smartlist_new();
+ DIGESTMAP_FOREACH(state_commits, key, const sr_commit_t *, commit) {
+ char *line = get_vote_line_from_commit(commit, sr_state_get_phase());
+ smartlist_add(state_commit_vote_lines, line);
+ } DIGESTMAP_FOREACH_END;
+
+ /* Sort the commit strings by version (string, not numeric), algorithm,
+ * and fingerprint. This makes sure the commit lines in votes are in a
+ * recognisable, stable order. */
+ smartlist_sort_strings(state_commit_vote_lines);
+
+ /* Now add the sorted list of commits to the vote */
+ smartlist_add_all(chunks, state_commit_vote_lines);
+ smartlist_free(state_commit_vote_lines);
+
+ /* Add the SRV value(s) if any. */
+ {
+ char *srv_lines = get_ns_str_from_sr_values(sr_state_get_previous_srv(),
+ sr_state_get_current_srv());
+ if (srv_lines) {
+ smartlist_add(chunks, srv_lines);
+ }
+ }
+
+ end:
+ vote_str = smartlist_join_strings(chunks, "", 0, NULL);
+ SMARTLIST_FOREACH(chunks, char *, s, tor_free(s));
+ smartlist_free(chunks);
+ return vote_str;
+}
+
+/* Return a heap-allocated string that should be put in the consensus and
+ * contains the shared randomness values. It's the responsibility of the
+ * caller to free the string. NULL is returned if no SRV(s) available.
+ *
+ * This is called when a consensus (any flavor) is bring created thus it
+ * should NEVER change the state nor the state should be changed in between
+ * consensus creation.
+ *
+ * <b>num_srv_agreements</b> is taken from the votes thus the voted value
+ * that should be used.
+ * */
+char *
+sr_get_string_for_consensus(const smartlist_t *votes,
+ int32_t num_srv_agreements)
+{
+ char *srv_str;
+ const or_options_t *options = get_options();
+
+ tor_assert(votes);
+
+ /* Not participating, avoid returning anything. */
+ if (!options->AuthDirSharedRandomness) {
+ log_info(LD_DIR, "SR: Support disabled (AuthDirSharedRandomness %d)",
+ options->AuthDirSharedRandomness);
+ goto end;
+ }
+
+ /* Set the global value of AuthDirNumSRVAgreements found in the votes. */
+ num_srv_agreements_from_vote = num_srv_agreements;
+
+ /* Check the votes and figure out if SRVs should be included in the final
+ * consensus. */
+ sr_srv_t *prev_srv = get_majority_srv_from_votes(votes, 0);
+ sr_srv_t *cur_srv = get_majority_srv_from_votes(votes, 1);
+ srv_str = get_ns_str_from_sr_values(prev_srv, cur_srv);
+ if (!srv_str) {
+ goto end;
+ }
+
+ return srv_str;
+ end:
+ return NULL;
+}
+
+/* We just computed a new <b>consensus</b>. Update our state with the SRVs
+ * from the consensus (might be NULL as well). Register the SRVs in our SR
+ * state and prepare for the upcoming protocol round. */
+void
+sr_act_post_consensus(const networkstatus_t *consensus)
+{
+ const or_options_t *options = get_options();
+
+ /* Don't act if our state hasn't been initialized. We can be called during
+ * boot time when loading consensus from disk which is prior to the
+ * initialization of the SR subsystem. We also should not be doing
+ * anything if we are _not_ a directory authority and if we are a bridge
+ * authority. */
+ if (!sr_state_is_initialized() || !authdir_mode_v3(options) ||
+ authdir_mode_bridge(options)) {
+ return;
+ }
+
+ /* Set the majority voted SRVs in our state even if both are NULL. It
+ * doesn't matter this is what the majority has decided. Obviously, we can
+ * only do that if we have a consensus. */
+ if (consensus) {
+ /* Start by freeing the current SRVs since the SRVs we believed during
+ * voting do not really matter. Now that all the votes are in, we use the
+ * majority's opinion on which are the active SRVs. */
+ sr_state_clean_srvs();
+ /* Reset the fresh flag of the SRV so we know that from now on we don't
+ * have a new SRV to vote for. We just used the one from the consensus
+ * decided by the majority. */
+ sr_state_unset_fresh_srv();
+ /* Set the SR values from the given consensus. */
- sr_state_set_previous_srv(srv_dup(consensus->sr_info.previous_srv));
- sr_state_set_current_srv(srv_dup(consensus->sr_info.current_srv));
++ sr_state_set_previous_srv(sr_srv_dup(consensus->sr_info.previous_srv));
++ sr_state_set_current_srv(sr_srv_dup(consensus->sr_info.current_srv));
+ }
+
+ /* Prepare our state so that it's ready for the next voting period. */
+ sr_state_update(voting_schedule_get_next_valid_after_time());
+}
+
+/* Initialize shared random subsystem. This MUST be called early in the boot
+ * process of tor. Return 0 on success else -1 on error. */
+int
+sr_init(int save_to_disk)
+{
+ return sr_state_init(save_to_disk, 1);
+}
+
+/* Save our state to disk and cleanup everything. */
+void
+sr_save_and_cleanup(void)
+{
+ sr_state_save();
+ sr_cleanup();
+}
+
+#ifdef TOR_UNIT_TESTS
+
+/* Set the global value of number of SRV agreements so the test can play
+ * along by calling specific functions that don't parse the votes prior for
+ * the AuthDirNumSRVAgreements value. */
+void
+set_num_srv_agreements(int32_t value)
+{
+ num_srv_agreements_from_vote = value;
+}
+
+#endif /* defined(TOR_UNIT_TESTS) */
diff --cc src/feature/dirauth/shared_random.h
index 25d95ebbc,000000000..0b45ad1ed
mode 100644,000000..100644
--- a/src/feature/dirauth/shared_random.h
+++ b/src/feature/dirauth/shared_random.h
@@@ -1,194 -1,0 +1,194 @@@
+/* Copyright (c) 2016-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_SHARED_RANDOM_H
+#define TOR_SHARED_RANDOM_H
+
+/*
+ * This file contains ABI/API of the shared random protocol defined in
+ * proposal #250. Every public functions and data structure are namespaced
+ * with "sr_" which stands for shared random.
+ */
+
+#include "core/or/or.h"
+
+/* Protocol version */
+#define SR_PROTO_VERSION 1
+/* Default digest algorithm. */
+#define SR_DIGEST_ALG DIGEST_SHA3_256
+/* Invariant token in the SRV calculation. */
+#define SR_SRV_TOKEN "shared-random"
+/* Don't count the NUL terminated byte even though the TOKEN has it. */
+#define SR_SRV_TOKEN_LEN (sizeof(SR_SRV_TOKEN) - 1)
+
+/* Length of the random number (in bytes). */
+#define SR_RANDOM_NUMBER_LEN 32
+/* Size of a decoded commit value in a vote or state. It's a hash and a
+ * timestamp. It adds up to 40 bytes. */
+#define SR_COMMIT_LEN (sizeof(uint64_t) + DIGEST256_LEN)
+/* Size of a decoded reveal value from a vote or state. It's a 64 bit
+ * timestamp and the hashed random number. This adds up to 40 bytes. */
+#define SR_REVEAL_LEN (sizeof(uint64_t) + DIGEST256_LEN)
+/* Size of SRV message length. The construction is has follow:
+ * "shared-random" | INT_8(reveal_num) | INT_4(version) | PREV_SRV */
+#define SR_SRV_MSG_LEN \
+ (SR_SRV_TOKEN_LEN + sizeof(uint64_t) + sizeof(uint32_t) + DIGEST256_LEN)
+
+/* Length of base64 encoded commit NOT including the NUL terminated byte.
+ * Formula is taken from base64_encode_size. This adds up to 56 bytes. */
+#define SR_COMMIT_BASE64_LEN (BASE64_LEN(SR_COMMIT_LEN))
+/* Length of base64 encoded reveal NOT including the NUL terminated byte.
+ * Formula is taken from base64_encode_size. This adds up to 56 bytes. */
+#define SR_REVEAL_BASE64_LEN (BASE64_LEN(SR_REVEAL_LEN))
+/* Length of base64 encoded shared random value. It's 32 bytes long so 44
+ * bytes from the base64_encode_size formula. That includes the '='
+ * character at the end. */
+#define SR_SRV_VALUE_BASE64_LEN (BASE64_LEN(DIGEST256_LEN))
+
+/* Assert if commit valid flag is not set. */
+#define ASSERT_COMMIT_VALID(c) tor_assert((c)->valid)
+
+/* Protocol phase. */
+typedef enum {
+ /* Commitment phase */
+ SR_PHASE_COMMIT = 1,
+ /* Reveal phase */
+ SR_PHASE_REVEAL = 2,
+} sr_phase_t;
+
+/* A shared random value (SRV). */
+typedef struct sr_srv_t {
+ /* The number of reveal values used to derive this SRV. */
+ uint64_t num_reveals;
+ /* The actual value. This is the stored result of SHA3-256. */
+ uint8_t value[DIGEST256_LEN];
+} sr_srv_t;
+
+/* A commit (either ours or from another authority). */
+typedef struct sr_commit_t {
+ /* Hashing algorithm used. */
+ digest_algorithm_t alg;
+ /* Indicate if this commit has been verified thus valid. */
+ unsigned int valid:1;
+
+ /* Commit owner info */
+
+ /* The RSA identity key of the authority and its base16 representation,
+ * which includes the NUL terminated byte. */
+ char rsa_identity[DIGEST_LEN];
+ char rsa_identity_hex[HEX_DIGEST_LEN + 1];
+
+ /* Commitment information */
+
+ /* Timestamp of reveal. Correspond to TIMESTAMP. */
+ uint64_t reveal_ts;
+ /* H(REVEAL) as found in COMMIT message. */
+ char hashed_reveal[DIGEST256_LEN];
+ /* Base64 encoded COMMIT. We use this to put it in our vote. */
+ char encoded_commit[SR_COMMIT_BASE64_LEN + 1];
+
+ /* Reveal information */
+
+ /* H(RN) which is what we used as the random value for this commit. We
+ * don't use the raw bytes since those are sent on the network thus
+ * avoiding possible information leaks of our PRNG. */
+ uint8_t random_number[SR_RANDOM_NUMBER_LEN];
+ /* Timestamp of commit. Correspond to TIMESTAMP. */
+ uint64_t commit_ts;
+ /* This is the whole reveal message. We use it during verification */
+ char encoded_reveal[SR_REVEAL_BASE64_LEN + 1];
+} sr_commit_t;
+
+/* API */
+
+/* Public methods used _outside_ of the module.
+ *
+ * We need to nullify them if the module is disabled. */
+#ifdef HAVE_MODULE_DIRAUTH
+
+int sr_init(int save_to_disk);
+void sr_save_and_cleanup(void);
+void sr_act_post_consensus(const networkstatus_t *consensus);
+
+#else /* HAVE_MODULE_DIRAUTH */
+
+static inline int
+sr_init(int save_to_disk)
+{
+ (void) save_to_disk;
+ /* Always return success. */
+ return 0;
+}
+
+static inline void
+sr_save_and_cleanup(void)
+{
+}
+
+static inline void
+sr_act_post_consensus(const networkstatus_t *consensus)
+{
+ (void) consensus;
+}
+
+#endif /* HAVE_MODULE_DIRAUTH */
+
+/* Public methods used only by dirauth code. */
+
+void sr_handle_received_commits(smartlist_t *commits,
+ crypto_pk_t *voter_key);
+sr_commit_t *sr_parse_commit(const smartlist_t *args);
+char *sr_get_string_for_vote(void);
+char *sr_get_string_for_consensus(const smartlist_t *votes,
+ int32_t num_srv_agreements);
+void sr_commit_free_(sr_commit_t *commit);
+#define sr_commit_free(sr) FREE_AND_NULL(sr_commit_t, sr_commit_free_, (sr))
+
+/* Private methods (only used by shared_random_state.c): */
+static inline
+const char *sr_commit_get_rsa_fpr(const sr_commit_t *commit)
+{
+ return commit->rsa_identity_hex;
+}
+
+void sr_compute_srv(void);
+sr_commit_t *sr_generate_our_commit(time_t timestamp,
+ const authority_cert_t *my_rsa_cert);
++sr_srv_t *sr_srv_dup(const sr_srv_t *orig);
+
+#ifdef SHARED_RANDOM_PRIVATE
+
+/* Encode */
+STATIC int reveal_encode(const sr_commit_t *commit, char *dst, size_t len);
+STATIC int commit_encode(const sr_commit_t *commit, char *dst, size_t len);
+/* Decode. */
+STATIC int commit_decode(const char *encoded, sr_commit_t *commit);
+STATIC int reveal_decode(const char *encoded, sr_commit_t *commit);
+
+STATIC int commit_has_reveal_value(const sr_commit_t *commit);
+
+STATIC int verify_commit_and_reveal(const sr_commit_t *commit);
+
+STATIC sr_srv_t *get_majority_srv_from_votes(const smartlist_t *votes,
+ int current);
+
+STATIC void save_commit_to_state(sr_commit_t *commit);
- STATIC sr_srv_t *srv_dup(const sr_srv_t *orig);
+STATIC int commitments_are_the_same(const sr_commit_t *commit_one,
+ const sr_commit_t *commit_two);
+STATIC int commit_is_authoritative(const sr_commit_t *commit,
+ const char *voter_key);
+STATIC int should_keep_commit(const sr_commit_t *commit,
+ const char *voter_key,
+ sr_phase_t phase);
+STATIC void save_commit_during_reveal_phase(const sr_commit_t *commit);
+
+#endif /* defined(SHARED_RANDOM_PRIVATE) */
+
+#ifdef TOR_UNIT_TESTS
+
+void set_num_srv_agreements(int32_t value);
+
+#endif /* TOR_UNIT_TESTS */
+
+#endif /* !defined(TOR_SHARED_RANDOM_H) */
+
diff --cc src/feature/dirauth/shared_random_state.c
index 92f0b3e73,000000000..a7b7480ed
mode 100644,000000..100644
--- a/src/feature/dirauth/shared_random_state.c
+++ b/src/feature/dirauth/shared_random_state.c
@@@ -1,1341 -1,0 +1,1377 @@@
+/* Copyright (c) 2016-2019, 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 "core/or/or.h"
+#include "app/config/config.h"
+#include "app/config/confparse.h"
+#include "lib/crypt_ops/crypto_util.h"
+#include "feature/dirauth/dirvote.h"
+#include "feature/nodelist/networkstatus.h"
+#include "feature/relay/router.h"
+#include "feature/dirauth/shared_random.h"
+#include "feature/hs_common/shared_random_client.h"
+#include "feature/dirauth/shared_random_state.h"
+#include "feature/dircommon/voting_schedule.h"
+#include "lib/encoding/confline.h"
+#include "lib/version/torversion.h"
+
+#include "app/config/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);
+static void disk_state_free_cb(void *);
+
+/* 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,
+ disk_state_free_cb,
+ &state_extra_var,
+};
+
++static void state_query_del_(sr_state_object_t obj_type, void *data);
++
+/* 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;
+}
+
+static void
+disk_state_free_cb(void *state)
+{
+ disk_state_free_(state);
+}
+
+/* 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;
+
+ if (BUG(!sr_disk_state))
+ return;
+ if (BUG(!sr_state))
+ return;
+
+ /* 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)
+{
+ if (BUG(!sr_state))
+ return;
+
+ /* 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)
+{
++ if (BUG(!sr_state))
++ return NULL;
++
+ 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. */
++ * <b>obj_type</b> and <b>data</b> needed for the action.
++ * PUT frees the previous data before replacing it, if needed. */
+static void
+state_query_put_(sr_state_object_t obj_type, void *data)
+{
++ if (BUG(!sr_state))
++ return;
++
+ switch (obj_type) {
+ case SR_STATE_OBJ_COMMIT:
+ {
+ sr_commit_t *commit = data;
+ tor_assert(commit);
++ /* commit_add_to_state() frees the old commit, if there is one */
+ commit_add_to_state(commit, sr_state);
+ break;
+ }
+ case SR_STATE_OBJ_CURSRV:
- sr_state->current_srv = (sr_srv_t *) data;
++ /* Check if the new pointer is the same as the old one: if it is, it's
++ * probably a bug. The caller may have confused current and previous,
++ * or they may have forgotten to sr_srv_dup().
++ * Putting NULL multiple times is allowed. */
++ if (!BUG(data && sr_state->current_srv == (sr_srv_t *) data)) {
++ /* We own the old SRV, so we need to free it. */
++ state_query_del_(SR_STATE_OBJ_CURSRV, NULL);
++ sr_state->current_srv = (sr_srv_t *) data;
++ }
+ break;
+ case SR_STATE_OBJ_PREVSRV:
- sr_state->previous_srv = (sr_srv_t *) data;
++ /* Check if the new pointer is the same as the old one: if it is, it's
++ * probably a bug. The caller may have confused current and previous,
++ * or they may have forgotten to sr_srv_dup().
++ * Putting NULL multiple times is allowed. */
++ if (!BUG(data && sr_state->previous_srv == (sr_srv_t *) data)) {
++ /* We own the old SRV, so we need to free it. */
++ state_query_del_(SR_STATE_OBJ_PREVSRV, NULL);
++ 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)
+{
++ if (BUG(!sr_state))
++ return;
++
+ 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;
+
++ if (BUG(!sr_state))
++ return;
++
+ 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
++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
++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. */
++/* Rotate SRV value by setting the previous SRV to the current SRV, and
++ * clearing the current SRV. */
+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. */
++ /* Set previous SRV to a copy of the current one. */
++ sr_state_set_previous_srv(sr_srv_dup(sr_state_get_current_srv()));
++ /* Free and NULL 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. */
++/* Return the previous SRV value from our state. Value CAN be NULL.
++ * The state object owns the SRV, so the calling code should not free the SRV.
++ * Use sr_srv_dup() if you want to keep a copy of the SRV. */
+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. */
++/* Return the current SRV value from our state. Value CAN be NULL.
++ * The state object owns the SRV, so the calling code should not free the SRV.
++ * Use sr_srv_dup() if you want to keep a copy of the SRV. */
+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;
+
+ if (BUG(!sr_state))
+ return;
+
+ /* 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 */
+ if (BUG(sr_state->n_reveal_rounds != 0))
+ return;
+ 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)
+{
+ if (BUG(!sr_state))
+ return;
+ 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) */
diff --cc src/feature/dirauth/shared_random_state.h
index 35626be3f,000000000..08f999f9d
mode 100644,000000..100644
--- a/src/feature/dirauth/shared_random_state.h
+++ b/src/feature/dirauth/shared_random_state.h
@@@ -1,146 -1,0 +1,148 @@@
+/* Copyright (c) 2016-2019, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_SHARED_RANDOM_STATE_H
+#define TOR_SHARED_RANDOM_STATE_H
+
+#include "feature/dirauth/shared_random.h"
+
+/* Action that can be performed on the state for any objects. */
+typedef enum {
+ SR_STATE_ACTION_GET = 1,
+ SR_STATE_ACTION_PUT = 2,
+ SR_STATE_ACTION_DEL = 3,
+ SR_STATE_ACTION_DEL_ALL = 4,
+ SR_STATE_ACTION_SAVE = 5,
+} sr_state_action_t;
+
+/* Object in the state that can be queried through the state API. */
+typedef enum {
+ /* Will return a single commit using an authority identity key. */
+ SR_STATE_OBJ_COMMIT,
+ /* Returns the entire list of commits from the state. */
+ SR_STATE_OBJ_COMMITS,
+ /* Return the current SRV object pointer. */
+ SR_STATE_OBJ_CURSRV,
+ /* Return the previous SRV object pointer. */
+ SR_STATE_OBJ_PREVSRV,
+ /* Return the phase. */
+ SR_STATE_OBJ_PHASE,
+ /* Get or Put the valid after time. */
+ SR_STATE_OBJ_VALID_AFTER,
+} sr_state_object_t;
+
+/* State of the protocol. It's also saved on disk in fname. This data
+ * structure MUST be synchronized at all time with the one on disk. */
+typedef struct sr_state_t {
+ /* Filename of the state file on disk. */
+ char *fname;
+ /* Version of the protocol. */
+ uint32_t version;
+ /* The valid-after of the voting period we have prepared the state for. */
+ time_t valid_after;
+ /* Until when is this state valid? */
+ time_t valid_until;
+ /* Protocol phase. */
+ sr_phase_t phase;
+
+ /* Number of runs completed. */
+ uint64_t n_protocol_runs;
+ /* The number of commitment rounds we've performed in this protocol run. */
+ unsigned int n_commit_rounds;
+ /* The number of reveal rounds we've performed in this protocol run. */
+ unsigned int n_reveal_rounds;
+
+ /* A map of all the received commitments for this protocol run. This is
+ * indexed by authority RSA identity digest. */
+ digestmap_t *commits;
+
+ /* Current and previous shared random value. */
+ sr_srv_t *previous_srv;
+ sr_srv_t *current_srv;
+
+ /* Indicate if the state contains an SRV that was _just_ generated. This is
+ * used during voting so that we know whether to use the super majority rule
+ * or not when deciding on keeping it for the consensus. It is _always_ set
+ * to 0 post consensus.
+ *
+ * EDGE CASE: if an authority computes a new SRV then immediately reboots
+ * and, once back up, votes for the current round, it won't know if the
+ * SRV is fresh or not ultimately making it _NOT_ use the super majority
+ * when deciding to put or not the SRV in the consensus. This is for now
+ * an acceptable very rare edge case. */
+ unsigned int is_srv_fresh:1;
+} sr_state_t;
+
+/* Persistent state of the protocol, as saved to disk. */
+typedef struct sr_disk_state_t {
+ uint32_t magic_;
+ /* Version of the protocol. */
+ int Version;
+ /* Version of our running tor. */
+ char *TorVersion;
+ /* Creation time of this state */
+ time_t ValidAfter;
+ /* State valid until? */
+ time_t ValidUntil;
+ /* All commits seen that are valid. */
+ struct config_line_t *Commit;
+ /* Previous and current shared random value. */
+ struct config_line_t *SharedRandValues;
+ /* Extra Lines for configuration we might not know. */
+ struct config_line_t *ExtraLines;
+} sr_disk_state_t;
+
+/* API */
+
+/* Public methods: */
+
+void sr_state_update(time_t valid_after);
+
+/* Private methods (only used by shared-random.c): */
+
+void sr_state_set_valid_after(time_t valid_after);
+sr_phase_t sr_state_get_phase(void);
+const sr_srv_t *sr_state_get_previous_srv(void);
+const sr_srv_t *sr_state_get_current_srv(void);
+void sr_state_set_previous_srv(const sr_srv_t *srv);
+void sr_state_set_current_srv(const sr_srv_t *srv);
+void sr_state_clean_srvs(void);
+digestmap_t *sr_state_get_commits(void);
+sr_commit_t *sr_state_get_commit(const char *rsa_fpr);
+void sr_state_add_commit(sr_commit_t *commit);
+void sr_state_delete_commits(void);
+void sr_state_copy_reveal_info(sr_commit_t *saved_commit,
+ const sr_commit_t *commit);
+unsigned int sr_state_srv_is_fresh(void);
+void sr_state_set_fresh_srv(void);
+void sr_state_unset_fresh_srv(void);
+int sr_state_init(int save_to_disk, int read_from_disk);
+int sr_state_is_initialized(void);
+void sr_state_save(void);
+void sr_state_free_all(void);
+
+#ifdef SHARED_RANDOM_STATE_PRIVATE
+
+STATIC int disk_state_load_from_disk_impl(const char *fname);
+
+STATIC sr_phase_t get_sr_protocol_phase(time_t valid_after);
+
+STATIC time_t get_state_valid_until_time(time_t now);
+STATIC const char *get_phase_str(sr_phase_t phase);
+STATIC void reset_state_for_new_protocol_run(time_t valid_after);
+STATIC void new_protocol_run(time_t valid_after);
+STATIC void state_rotate_srv(void);
+STATIC int is_phase_transition(sr_phase_t next_phase);
+
+#endif /* defined(SHARED_RANDOM_STATE_PRIVATE) */
+
+#ifdef TOR_UNIT_TESTS
+
+STATIC void set_sr_phase(sr_phase_t phase);
+STATIC sr_state_t *get_sr_state(void);
++STATIC void state_del_previous_srv(void);
++STATIC void state_del_current_srv(void);
+
+#endif /* defined(TOR_UNIT_TESTS) */
+
+#endif /* !defined(TOR_SHARED_RANDOM_STATE_H) */
