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- /* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2018, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /**
- * \file rendcommon.c
- * \brief Rendezvous implementation: shared code between
- * introducers, services, clients, and rendezvous points.
- **/
- #define RENDCOMMON_PRIVATE
- #include "core/or/or.h"
- #include "core/or/circuitbuild.h"
- #include "core/or/circuitlist.h"
- #include "core/or/circuituse.h"
- #include "app/config/config.h"
- #include "feature/control/control.h"
- #include "lib/crypt_ops/crypto_rand.h"
- #include "lib/crypt_ops/crypto_util.h"
- #include "feature/hs/hs_client.h"
- #include "feature/hs/hs_common.h"
- #include "feature/hs/hs_intropoint.h"
- #include "feature/nodelist/networkstatus.h"
- #include "feature/rend/rendclient.h"
- #include "feature/rend/rendcommon.h"
- #include "feature/rend/rendmid.h"
- #include "feature/rend/rendservice.h"
- #include "feature/stats/rephist.h"
- #include "feature/hs_common/replaycache.h"
- #include "feature/relay/router.h"
- #include "feature/nodelist/routerlist.h"
- #include "feature/nodelist/routerparse.h"
- #include "core/or/cpath_build_state_st.h"
- #include "core/or/crypt_path_st.h"
- #include "core/or/extend_info_st.h"
- #include "feature/nodelist/networkstatus_st.h"
- #include "core/or/origin_circuit_st.h"
- #include "feature/rend/rend_encoded_v2_service_descriptor_st.h"
- #include "feature/rend/rend_intro_point_st.h"
- #include "feature/rend/rend_service_descriptor_st.h"
- #include "feature/nodelist/routerstatus_st.h"
- /** Return 0 if one and two are the same service ids, else -1 or 1 */
- int
- rend_cmp_service_ids(const char *one, const char *two)
- {
- return strcasecmp(one,two);
- }
- /** Free the storage held by the service descriptor <b>desc</b>.
- */
- void
- rend_service_descriptor_free_(rend_service_descriptor_t *desc)
- {
- if (!desc)
- return;
- if (desc->pk)
- crypto_pk_free(desc->pk);
- if (desc->intro_nodes) {
- SMARTLIST_FOREACH(desc->intro_nodes, rend_intro_point_t *, intro,
- rend_intro_point_free(intro););
- smartlist_free(desc->intro_nodes);
- }
- if (desc->successful_uploads) {
- SMARTLIST_FOREACH(desc->successful_uploads, char *, c, tor_free(c););
- smartlist_free(desc->successful_uploads);
- }
- tor_free(desc);
- }
- /** Length of the descriptor cookie that is used for versioned hidden
- * service descriptors. */
- #define REND_DESC_COOKIE_LEN 16
- /** Length of the replica number that is used to determine the secret ID
- * part of versioned hidden service descriptors. */
- #define REND_REPLICA_LEN 1
- /** Compute the descriptor ID for <b>service_id</b> of length
- * <b>REND_SERVICE_ID_LEN</b> and <b>secret_id_part</b> of length
- * <b>DIGEST_LEN</b>, and write it to <b>descriptor_id_out</b> of length
- * <b>DIGEST_LEN</b>. */
- void
- rend_get_descriptor_id_bytes(char *descriptor_id_out,
- const char *service_id,
- const char *secret_id_part)
- {
- crypto_digest_t *digest = crypto_digest_new();
- crypto_digest_add_bytes(digest, service_id, REND_SERVICE_ID_LEN);
- crypto_digest_add_bytes(digest, secret_id_part, DIGEST_LEN);
- crypto_digest_get_digest(digest, descriptor_id_out, DIGEST_LEN);
- crypto_digest_free(digest);
- }
- /** Compute the secret ID part for time_period,
- * a <b>descriptor_cookie</b> of length
- * <b>REND_DESC_COOKIE_LEN</b> which may also be <b>NULL</b> if no
- * descriptor_cookie shall be used, and <b>replica</b>, and write it to
- * <b>secret_id_part</b> of length DIGEST_LEN. */
- static void
- get_secret_id_part_bytes(char *secret_id_part, uint32_t time_period,
- const char *descriptor_cookie, uint8_t replica)
- {
- crypto_digest_t *digest = crypto_digest_new();
- time_period = htonl(time_period);
- crypto_digest_add_bytes(digest, (char*)&time_period, sizeof(uint32_t));
- if (descriptor_cookie) {
- crypto_digest_add_bytes(digest, descriptor_cookie,
- REND_DESC_COOKIE_LEN);
- }
- crypto_digest_add_bytes(digest, (const char *)&replica, REND_REPLICA_LEN);
- crypto_digest_get_digest(digest, secret_id_part, DIGEST_LEN);
- crypto_digest_free(digest);
- }
- /** Return the time period for time <b>now</b> plus a potentially
- * intended <b>deviation</b> of one or more periods, based on the first byte
- * of <b>service_id</b>. */
- static uint32_t
- get_time_period(time_t now, uint8_t deviation, const char *service_id)
- {
- /* The time period is the number of REND_TIME_PERIOD_V2_DESC_VALIDITY
- * intervals that have passed since the epoch, offset slightly so that
- * each service's time periods start and end at a fraction of that
- * period based on their first byte. */
- return (uint32_t)
- (now + ((uint8_t) *service_id) * REND_TIME_PERIOD_V2_DESC_VALIDITY / 256)
- / REND_TIME_PERIOD_V2_DESC_VALIDITY + deviation;
- }
- /** Compute the time in seconds that a descriptor that is generated
- * <b>now</b> for <b>service_id</b> will be valid. */
- static uint32_t
- get_seconds_valid(time_t now, const char *service_id)
- {
- uint32_t result = REND_TIME_PERIOD_V2_DESC_VALIDITY -
- ((uint32_t)
- (now + ((uint8_t) *service_id) * REND_TIME_PERIOD_V2_DESC_VALIDITY / 256)
- % REND_TIME_PERIOD_V2_DESC_VALIDITY);
- return result;
- }
- /** Compute the binary <b>desc_id_out</b> (DIGEST_LEN bytes long) for a given
- * base32-encoded <b>service_id</b> and optional unencoded
- * <b>descriptor_cookie</b> of length REND_DESC_COOKIE_LEN,
- * at time <b>now</b> for replica number
- * <b>replica</b>. <b>desc_id</b> needs to have <b>DIGEST_LEN</b> bytes
- * free. Return 0 for success, -1 otherwise. */
- int
- rend_compute_v2_desc_id(char *desc_id_out, const char *service_id,
- const char *descriptor_cookie, time_t now,
- uint8_t replica)
- {
- char service_id_binary[REND_SERVICE_ID_LEN];
- char secret_id_part[DIGEST_LEN];
- uint32_t time_period;
- if (!service_id ||
- strlen(service_id) != REND_SERVICE_ID_LEN_BASE32) {
- log_warn(LD_REND, "Could not compute v2 descriptor ID: "
- "Illegal service ID: %s",
- safe_str(service_id));
- return -1;
- }
- if (replica >= REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS) {
- log_warn(LD_REND, "Could not compute v2 descriptor ID: "
- "Replica number out of range: %d", replica);
- return -1;
- }
- /* Convert service ID to binary. */
- if (base32_decode(service_id_binary, REND_SERVICE_ID_LEN,
- service_id, REND_SERVICE_ID_LEN_BASE32) < 0) {
- log_warn(LD_REND, "Could not compute v2 descriptor ID: "
- "Illegal characters in service ID: %s",
- safe_str_client(service_id));
- return -1;
- }
- /* Calculate current time-period. */
- time_period = get_time_period(now, 0, service_id_binary);
- /* Calculate secret-id-part = h(time-period | desc-cookie | replica). */
- get_secret_id_part_bytes(secret_id_part, time_period, descriptor_cookie,
- replica);
- /* Calculate descriptor ID: H(permanent-id | secret-id-part) */
- rend_get_descriptor_id_bytes(desc_id_out, service_id_binary, secret_id_part);
- return 0;
- }
- /** Encode the introduction points in <b>desc</b> and write the result to a
- * newly allocated string pointed to by <b>encoded</b>. Return 0 for
- * success, -1 otherwise. */
- static int
- rend_encode_v2_intro_points(char **encoded, rend_service_descriptor_t *desc)
- {
- size_t unenc_len;
- char *unenc = NULL;
- size_t unenc_written = 0;
- int i;
- int r = -1;
- /* Assemble unencrypted list of introduction points. */
- unenc_len = smartlist_len(desc->intro_nodes) * 1000; /* too long, but ok. */
- unenc = tor_malloc_zero(unenc_len);
- for (i = 0; i < smartlist_len(desc->intro_nodes); i++) {
- char id_base32[REND_INTRO_POINT_ID_LEN_BASE32 + 1];
- char *onion_key = NULL;
- size_t onion_key_len;
- crypto_pk_t *intro_key;
- char *service_key = NULL;
- char *address = NULL;
- size_t service_key_len;
- int res;
- rend_intro_point_t *intro = smartlist_get(desc->intro_nodes, i);
- /* Obtain extend info with introduction point details. */
- extend_info_t *info = intro->extend_info;
- /* Encode introduction point ID. */
- base32_encode(id_base32, sizeof(id_base32),
- info->identity_digest, DIGEST_LEN);
- /* Encode onion key. */
- if (crypto_pk_write_public_key_to_string(info->onion_key, &onion_key,
- &onion_key_len) < 0) {
- log_warn(LD_REND, "Could not write onion key.");
- goto done;
- }
- /* Encode intro key. */
- intro_key = intro->intro_key;
- if (!intro_key ||
- crypto_pk_write_public_key_to_string(intro_key, &service_key,
- &service_key_len) < 0) {
- log_warn(LD_REND, "Could not write intro key.");
- tor_free(onion_key);
- goto done;
- }
- /* Assemble everything for this introduction point. */
- address = tor_addr_to_str_dup(&info->addr);
- res = tor_snprintf(unenc + unenc_written, unenc_len - unenc_written,
- "introduction-point %s\n"
- "ip-address %s\n"
- "onion-port %d\n"
- "onion-key\n%s"
- "service-key\n%s",
- id_base32,
- address,
- info->port,
- onion_key,
- service_key);
- tor_free(address);
- tor_free(onion_key);
- tor_free(service_key);
- if (res < 0) {
- log_warn(LD_REND, "Not enough space for writing introduction point "
- "string.");
- goto done;
- }
- /* Update total number of written bytes for unencrypted intro points. */
- unenc_written += res;
- }
- /* Finalize unencrypted introduction points. */
- if (unenc_len < unenc_written + 2) {
- log_warn(LD_REND, "Not enough space for finalizing introduction point "
- "string.");
- goto done;
- }
- unenc[unenc_written++] = '\n';
- unenc[unenc_written++] = 0;
- *encoded = unenc;
- r = 0;
- done:
- if (r<0)
- tor_free(unenc);
- return r;
- }
- /** Encrypt the encoded introduction points in <b>encoded</b> using
- * authorization type 'basic' with <b>client_cookies</b> and write the
- * result to a newly allocated string pointed to by <b>encrypted_out</b> of
- * length <b>encrypted_len_out</b>. Return 0 for success, -1 otherwise. */
- static int
- rend_encrypt_v2_intro_points_basic(char **encrypted_out,
- size_t *encrypted_len_out,
- const char *encoded,
- smartlist_t *client_cookies)
- {
- int r = -1, i, pos, enclen, client_blocks;
- size_t len, client_entries_len;
- char *enc = NULL, iv[CIPHER_IV_LEN], *client_part = NULL,
- session_key[CIPHER_KEY_LEN];
- smartlist_t *encrypted_session_keys = NULL;
- crypto_digest_t *digest;
- crypto_cipher_t *cipher;
- tor_assert(encoded);
- tor_assert(client_cookies && smartlist_len(client_cookies) > 0);
- /* Generate session key. */
- crypto_rand(session_key, CIPHER_KEY_LEN);
- /* Determine length of encrypted introduction points including session
- * keys. */
- client_blocks = 1 + ((smartlist_len(client_cookies) - 1) /
- REND_BASIC_AUTH_CLIENT_MULTIPLE);
- client_entries_len = client_blocks * REND_BASIC_AUTH_CLIENT_MULTIPLE *
- REND_BASIC_AUTH_CLIENT_ENTRY_LEN;
- len = 2 + client_entries_len + CIPHER_IV_LEN + strlen(encoded);
- if (client_blocks >= 256) {
- log_warn(LD_REND, "Too many clients in introduction point string.");
- goto done;
- }
- enc = tor_malloc_zero(len);
- enc[0] = 0x01; /* type of authorization. */
- enc[1] = (uint8_t)client_blocks;
- /* Encrypt with random session key. */
- enclen = crypto_cipher_encrypt_with_iv(session_key,
- enc + 2 + client_entries_len,
- CIPHER_IV_LEN + strlen(encoded), encoded, strlen(encoded));
- if (enclen < 0) {
- log_warn(LD_REND, "Could not encrypt introduction point string.");
- goto done;
- }
- memcpy(iv, enc + 2 + client_entries_len, CIPHER_IV_LEN);
- /* Encrypt session key for cookies, determine client IDs, and put both
- * in a smartlist. */
- encrypted_session_keys = smartlist_new();
- SMARTLIST_FOREACH_BEGIN(client_cookies, const char *, cookie) {
- client_part = tor_malloc_zero(REND_BASIC_AUTH_CLIENT_ENTRY_LEN);
- /* Encrypt session key. */
- cipher = crypto_cipher_new(cookie);
- if (crypto_cipher_encrypt(cipher, client_part +
- REND_BASIC_AUTH_CLIENT_ID_LEN,
- session_key, CIPHER_KEY_LEN) < 0) {
- log_warn(LD_REND, "Could not encrypt session key for client.");
- crypto_cipher_free(cipher);
- tor_free(client_part);
- goto done;
- }
- crypto_cipher_free(cipher);
- /* Determine client ID. */
- digest = crypto_digest_new();
- crypto_digest_add_bytes(digest, cookie, REND_DESC_COOKIE_LEN);
- crypto_digest_add_bytes(digest, iv, CIPHER_IV_LEN);
- crypto_digest_get_digest(digest, client_part,
- REND_BASIC_AUTH_CLIENT_ID_LEN);
- crypto_digest_free(digest);
- /* Put both together. */
- smartlist_add(encrypted_session_keys, client_part);
- } SMARTLIST_FOREACH_END(cookie);
- /* Add some fake client IDs and encrypted session keys. */
- for (i = (smartlist_len(client_cookies) - 1) %
- REND_BASIC_AUTH_CLIENT_MULTIPLE;
- i < REND_BASIC_AUTH_CLIENT_MULTIPLE - 1; i++) {
- client_part = tor_malloc_zero(REND_BASIC_AUTH_CLIENT_ENTRY_LEN);
- crypto_rand(client_part, REND_BASIC_AUTH_CLIENT_ENTRY_LEN);
- smartlist_add(encrypted_session_keys, client_part);
- }
- /* Sort smartlist and put elements in result in order. */
- smartlist_sort_digests(encrypted_session_keys);
- pos = 2;
- SMARTLIST_FOREACH(encrypted_session_keys, const char *, entry, {
- memcpy(enc + pos, entry, REND_BASIC_AUTH_CLIENT_ENTRY_LEN);
- pos += REND_BASIC_AUTH_CLIENT_ENTRY_LEN;
- });
- *encrypted_out = enc;
- *encrypted_len_out = len;
- enc = NULL; /* prevent free. */
- r = 0;
- done:
- tor_free(enc);
- if (encrypted_session_keys) {
- SMARTLIST_FOREACH(encrypted_session_keys, char *, d, tor_free(d););
- smartlist_free(encrypted_session_keys);
- }
- return r;
- }
- /** Encrypt the encoded introduction points in <b>encoded</b> using
- * authorization type 'stealth' with <b>descriptor_cookie</b> of length
- * REND_DESC_COOKIE_LEN and write the result to a newly allocated string
- * pointed to by <b>encrypted_out</b> of length <b>encrypted_len_out</b>.
- * Return 0 for success, -1 otherwise. */
- static int
- rend_encrypt_v2_intro_points_stealth(char **encrypted_out,
- size_t *encrypted_len_out,
- const char *encoded,
- const char *descriptor_cookie)
- {
- int r = -1, enclen;
- char *enc;
- tor_assert(encoded);
- tor_assert(descriptor_cookie);
- enc = tor_malloc_zero(1 + CIPHER_IV_LEN + strlen(encoded));
- enc[0] = 0x02; /* Auth type */
- enclen = crypto_cipher_encrypt_with_iv(descriptor_cookie,
- enc + 1,
- CIPHER_IV_LEN+strlen(encoded),
- encoded, strlen(encoded));
- if (enclen < 0) {
- log_warn(LD_REND, "Could not encrypt introduction point string.");
- goto done;
- }
- *encrypted_out = enc;
- *encrypted_len_out = enclen;
- enc = NULL; /* prevent free */
- r = 0;
- done:
- tor_free(enc);
- return r;
- }
- /** Attempt to parse the given <b>desc_str</b> and return true if this
- * succeeds, false otherwise. */
- STATIC int
- rend_desc_v2_is_parsable(rend_encoded_v2_service_descriptor_t *desc)
- {
- rend_service_descriptor_t *test_parsed = NULL;
- char test_desc_id[DIGEST_LEN];
- char *test_intro_content = NULL;
- size_t test_intro_size;
- size_t test_encoded_size;
- const char *test_next;
- int res = rend_parse_v2_service_descriptor(&test_parsed, test_desc_id,
- &test_intro_content,
- &test_intro_size,
- &test_encoded_size,
- &test_next, desc->desc_str, 1);
- rend_service_descriptor_free(test_parsed);
- tor_free(test_intro_content);
- return (res >= 0);
- }
- /** Free the storage held by an encoded v2 service descriptor. */
- void
- rend_encoded_v2_service_descriptor_free_(
- rend_encoded_v2_service_descriptor_t *desc)
- {
- if (!desc)
- return;
- tor_free(desc->desc_str);
- tor_free(desc);
- }
- /** Free the storage held by an introduction point info. */
- void
- rend_intro_point_free_(rend_intro_point_t *intro)
- {
- if (!intro)
- return;
- extend_info_free(intro->extend_info);
- crypto_pk_free(intro->intro_key);
- if (intro->accepted_intro_rsa_parts != NULL) {
- replaycache_free(intro->accepted_intro_rsa_parts);
- }
- tor_free(intro);
- }
- /** Encode a set of rend_encoded_v2_service_descriptor_t's for <b>desc</b>
- * at time <b>now</b> using <b>service_key</b>, depending on
- * <b>auth_type</b> a <b>descriptor_cookie</b> and a list of
- * <b>client_cookies</b> (which are both <b>NULL</b> if no client
- * authorization is performed), and <b>period</b> (e.g. 0 for the current
- * period, 1 for the next period, etc.) and add them to the existing list
- * <b>descs_out</b>; return the number of seconds that the descriptors will
- * be found by clients, or -1 if the encoding was not successful. */
- int
- rend_encode_v2_descriptors(smartlist_t *descs_out,
- rend_service_descriptor_t *desc, time_t now,
- uint8_t period, rend_auth_type_t auth_type,
- crypto_pk_t *client_key,
- smartlist_t *client_cookies)
- {
- char service_id[DIGEST_LEN];
- char service_id_base32[REND_SERVICE_ID_LEN_BASE32+1];
- uint32_t time_period;
- char *ipos_base64 = NULL, *ipos = NULL, *ipos_encrypted = NULL,
- *descriptor_cookie = NULL;
- size_t ipos_len = 0, ipos_encrypted_len = 0;
- int k;
- uint32_t seconds_valid;
- crypto_pk_t *service_key;
- if (!desc) {
- log_warn(LD_BUG, "Could not encode v2 descriptor: No desc given.");
- return -1;
- }
- service_key = (auth_type == REND_STEALTH_AUTH) ? client_key : desc->pk;
- tor_assert(service_key);
- if (auth_type == REND_STEALTH_AUTH) {
- descriptor_cookie = smartlist_get(client_cookies, 0);
- tor_assert(descriptor_cookie);
- }
- /* Obtain service_id from public key. */
- if (crypto_pk_get_digest(service_key, service_id) < 0) {
- log_warn(LD_BUG, "Couldn't compute service key digest.");
- return -1;
- }
- /* Calculate current time-period. */
- time_period = get_time_period(now, period, service_id);
- /* Determine how many seconds the descriptor will be valid. */
- seconds_valid = period * REND_TIME_PERIOD_V2_DESC_VALIDITY +
- get_seconds_valid(now, service_id);
- /* Assemble, possibly encrypt, and encode introduction points. */
- if (smartlist_len(desc->intro_nodes) > 0) {
- if (rend_encode_v2_intro_points(&ipos, desc) < 0) {
- log_warn(LD_REND, "Encoding of introduction points did not succeed.");
- return -1;
- }
- switch (auth_type) {
- case REND_NO_AUTH:
- ipos_len = strlen(ipos);
- break;
- case REND_BASIC_AUTH:
- if (rend_encrypt_v2_intro_points_basic(&ipos_encrypted,
- &ipos_encrypted_len, ipos,
- client_cookies) < 0) {
- log_warn(LD_REND, "Encrypting of introduction points did not "
- "succeed.");
- tor_free(ipos);
- return -1;
- }
- tor_free(ipos);
- ipos = ipos_encrypted;
- ipos_len = ipos_encrypted_len;
- break;
- case REND_STEALTH_AUTH:
- if (rend_encrypt_v2_intro_points_stealth(&ipos_encrypted,
- &ipos_encrypted_len, ipos,
- descriptor_cookie) < 0) {
- log_warn(LD_REND, "Encrypting of introduction points did not "
- "succeed.");
- tor_free(ipos);
- return -1;
- }
- tor_free(ipos);
- ipos = ipos_encrypted;
- ipos_len = ipos_encrypted_len;
- break;
- default:
- log_warn(LD_REND|LD_BUG, "Unrecognized authorization type %d",
- (int)auth_type);
- tor_free(ipos);
- return -1;
- }
- /* Base64-encode introduction points. */
- ipos_base64 = tor_calloc(ipos_len, 2);
- if (base64_encode(ipos_base64, ipos_len * 2, ipos, ipos_len,
- BASE64_ENCODE_MULTILINE)<0) {
- log_warn(LD_REND, "Could not encode introduction point string to "
- "base64. length=%d", (int)ipos_len);
- tor_free(ipos_base64);
- tor_free(ipos);
- return -1;
- }
- tor_free(ipos);
- }
- /* Encode REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS descriptors. */
- for (k = 0; k < REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS; k++) {
- char secret_id_part[DIGEST_LEN];
- char secret_id_part_base32[REND_SECRET_ID_PART_LEN_BASE32 + 1];
- char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
- char *permanent_key = NULL;
- size_t permanent_key_len;
- char published[ISO_TIME_LEN+1];
- int i;
- char protocol_versions_string[16]; /* max len: "0,1,2,3,4,5,6,7\0" */
- size_t protocol_versions_written;
- size_t desc_len;
- char *desc_str = NULL;
- int result = 0;
- size_t written = 0;
- char desc_digest[DIGEST_LEN];
- rend_encoded_v2_service_descriptor_t *enc =
- tor_malloc_zero(sizeof(rend_encoded_v2_service_descriptor_t));
- /* Calculate secret-id-part = h(time-period | cookie | replica). */
- get_secret_id_part_bytes(secret_id_part, time_period, descriptor_cookie,
- k);
- base32_encode(secret_id_part_base32, sizeof(secret_id_part_base32),
- secret_id_part, DIGEST_LEN);
- /* Calculate descriptor ID. */
- rend_get_descriptor_id_bytes(enc->desc_id, service_id, secret_id_part);
- base32_encode(desc_id_base32, sizeof(desc_id_base32),
- enc->desc_id, DIGEST_LEN);
- /* PEM-encode the public key */
- if (crypto_pk_write_public_key_to_string(service_key, &permanent_key,
- &permanent_key_len) < 0) {
- log_warn(LD_BUG, "Could not write public key to string.");
- rend_encoded_v2_service_descriptor_free(enc);
- goto err;
- }
- /* Encode timestamp. */
- format_iso_time(published, desc->timestamp);
- /* Write protocol-versions bitmask to comma-separated value string. */
- protocol_versions_written = 0;
- for (i = 0; i < 8; i++) {
- if (desc->protocols & 1 << i) {
- tor_snprintf(protocol_versions_string + protocol_versions_written,
- 16 - protocol_versions_written, "%d,", i);
- protocol_versions_written += 2;
- }
- }
- if (protocol_versions_written)
- protocol_versions_string[protocol_versions_written - 1] = '\0';
- else
- protocol_versions_string[0]= '\0';
- /* Assemble complete descriptor. */
- desc_len = 2000 + smartlist_len(desc->intro_nodes) * 1000; /* far too long,
- but okay.*/
- enc->desc_str = desc_str = tor_malloc_zero(desc_len);
- result = tor_snprintf(desc_str, desc_len,
- "rendezvous-service-descriptor %s\n"
- "version 2\n"
- "permanent-key\n%s"
- "secret-id-part %s\n"
- "publication-time %s\n"
- "protocol-versions %s\n",
- desc_id_base32,
- permanent_key,
- secret_id_part_base32,
- published,
- protocol_versions_string);
- tor_free(permanent_key);
- if (result < 0) {
- log_warn(LD_BUG, "Descriptor ran out of room.");
- rend_encoded_v2_service_descriptor_free(enc);
- goto err;
- }
- written = result;
- /* Add introduction points. */
- if (ipos_base64) {
- result = tor_snprintf(desc_str + written, desc_len - written,
- "introduction-points\n"
- "-----BEGIN MESSAGE-----\n%s"
- "-----END MESSAGE-----\n",
- ipos_base64);
- if (result < 0) {
- log_warn(LD_BUG, "could not write introduction points.");
- rend_encoded_v2_service_descriptor_free(enc);
- goto err;
- }
- written += result;
- }
- /* Add signature. */
- strlcpy(desc_str + written, "signature\n", desc_len - written);
- written += strlen(desc_str + written);
- if (crypto_digest(desc_digest, desc_str, written) < 0) {
- log_warn(LD_BUG, "could not create digest.");
- rend_encoded_v2_service_descriptor_free(enc);
- goto err;
- }
- if (router_append_dirobj_signature(desc_str + written,
- desc_len - written,
- desc_digest, DIGEST_LEN,
- service_key) < 0) {
- log_warn(LD_BUG, "Couldn't sign desc.");
- rend_encoded_v2_service_descriptor_free(enc);
- goto err;
- }
- written += strlen(desc_str+written);
- if (written+2 > desc_len) {
- log_warn(LD_BUG, "Could not finish desc.");
- rend_encoded_v2_service_descriptor_free(enc);
- goto err;
- }
- desc_str[written++] = 0;
- /* Check if we can parse our own descriptor. */
- if (!rend_desc_v2_is_parsable(enc)) {
- log_warn(LD_BUG, "Could not parse my own descriptor: %s", desc_str);
- rend_encoded_v2_service_descriptor_free(enc);
- goto err;
- }
- smartlist_add(descs_out, enc);
- /* Add the uploaded descriptor to the local service's descriptor cache */
- rend_cache_store_v2_desc_as_service(enc->desc_str);
- base32_encode(service_id_base32, sizeof(service_id_base32),
- service_id, REND_SERVICE_ID_LEN);
- control_event_hs_descriptor_created(service_id_base32, desc_id_base32, k);
- }
- log_info(LD_REND, "Successfully encoded a v2 descriptor and "
- "confirmed that it is parsable.");
- goto done;
- err:
- SMARTLIST_FOREACH(descs_out, rend_encoded_v2_service_descriptor_t *, d,
- rend_encoded_v2_service_descriptor_free(d););
- smartlist_clear(descs_out);
- seconds_valid = -1;
- done:
- tor_free(ipos_base64);
- return seconds_valid;
- }
- /** Sets <b>out</b> to the first 10 bytes of the digest of <b>pk</b>,
- * base32 encoded. NUL-terminates out. (We use this string to
- * identify services in directory requests and .onion URLs.)
- */
- int
- rend_get_service_id(crypto_pk_t *pk, char *out)
- {
- char buf[DIGEST_LEN];
- tor_assert(pk);
- if (crypto_pk_get_digest(pk, buf) < 0)
- return -1;
- base32_encode(out, REND_SERVICE_ID_LEN_BASE32+1, buf, REND_SERVICE_ID_LEN);
- return 0;
- }
- /** Return true iff <b>query</b> is a syntactically valid service ID (as
- * generated by rend_get_service_id). */
- int
- rend_valid_v2_service_id(const char *query)
- {
- if (strlen(query) != REND_SERVICE_ID_LEN_BASE32)
- return 0;
- if (strspn(query, BASE32_CHARS) != REND_SERVICE_ID_LEN_BASE32)
- return 0;
- return 1;
- }
- /** Return true iff <b>query</b> is a syntactically valid descriptor ID.
- * (as generated by rend_get_descriptor_id_bytes). */
- int
- rend_valid_descriptor_id(const char *query)
- {
- if (strlen(query) != REND_DESC_ID_V2_LEN_BASE32) {
- goto invalid;
- }
- if (strspn(query, BASE32_CHARS) != REND_DESC_ID_V2_LEN_BASE32) {
- goto invalid;
- }
- return 1;
- invalid:
- return 0;
- }
- /** Return true iff <b>client_name</b> is a syntactically valid name
- * for rendezvous client authentication. */
- int
- rend_valid_client_name(const char *client_name)
- {
- size_t len = strlen(client_name);
- if (len < 1 || len > REND_CLIENTNAME_MAX_LEN) {
- return 0;
- }
- if (strspn(client_name, REND_LEGAL_CLIENTNAME_CHARACTERS) != len) {
- return 0;
- }
- return 1;
- }
- /** Called when we get a rendezvous-related relay cell on circuit
- * <b>circ</b>. Dispatch on rendezvous relay command. */
- void
- rend_process_relay_cell(circuit_t *circ, const crypt_path_t *layer_hint,
- int command, size_t length,
- const uint8_t *payload)
- {
- or_circuit_t *or_circ = NULL;
- origin_circuit_t *origin_circ = NULL;
- int r = -2;
- if (CIRCUIT_IS_ORIGIN(circ)) {
- origin_circ = TO_ORIGIN_CIRCUIT(circ);
- if (!layer_hint || layer_hint != origin_circ->cpath->prev) {
- log_fn(LOG_PROTOCOL_WARN, LD_APP,
- "Relay cell (rend purpose %d) from wrong hop on origin circ",
- command);
- origin_circ = NULL;
- }
- } else {
- or_circ = TO_OR_CIRCUIT(circ);
- }
- switch (command) {
- case RELAY_COMMAND_ESTABLISH_INTRO:
- if (or_circ)
- r = hs_intro_received_establish_intro(or_circ,payload,length);
- break;
- case RELAY_COMMAND_ESTABLISH_RENDEZVOUS:
- if (or_circ)
- r = rend_mid_establish_rendezvous(or_circ,payload,length);
- break;
- case RELAY_COMMAND_INTRODUCE1:
- if (or_circ)
- r = hs_intro_received_introduce1(or_circ,payload,length);
- break;
- case RELAY_COMMAND_INTRODUCE2:
- if (origin_circ)
- r = hs_service_receive_introduce2(origin_circ,payload,length);
- break;
- case RELAY_COMMAND_INTRODUCE_ACK:
- if (origin_circ)
- r = hs_client_receive_introduce_ack(origin_circ,payload,length);
- break;
- case RELAY_COMMAND_RENDEZVOUS1:
- if (or_circ)
- r = rend_mid_rendezvous(or_circ,payload,length);
- break;
- case RELAY_COMMAND_RENDEZVOUS2:
- if (origin_circ)
- r = hs_client_receive_rendezvous2(origin_circ,payload,length);
- break;
- case RELAY_COMMAND_INTRO_ESTABLISHED:
- if (origin_circ)
- r = hs_service_receive_intro_established(origin_circ,payload,length);
- break;
- case RELAY_COMMAND_RENDEZVOUS_ESTABLISHED:
- if (origin_circ)
- r = hs_client_receive_rendezvous_acked(origin_circ,payload,length);
- break;
- default:
- tor_fragile_assert();
- }
- if (r == 0 && origin_circ) {
- /* This was a valid cell. Count it as delivered + overhead. */
- circuit_read_valid_data(origin_circ, length);
- }
- if (r == -2)
- log_info(LD_PROTOCOL, "Dropping cell (type %d) for wrong circuit type.",
- command);
- }
- /** Determine the routers that are responsible for <b>id</b> (binary) and
- * add pointers to those routers' routerstatus_t to <b>responsible_dirs</b>.
- * Return -1 if we're returning an empty smartlist, else return 0.
- */
- int
- hid_serv_get_responsible_directories(smartlist_t *responsible_dirs,
- const char *id)
- {
- int start, found, n_added = 0, i;
- networkstatus_t *c = networkstatus_get_latest_consensus();
- if (!c || !smartlist_len(c->routerstatus_list)) {
- log_warn(LD_REND, "We don't have a consensus, so we can't perform v2 "
- "rendezvous operations.");
- return -1;
- }
- tor_assert(id);
- start = networkstatus_vote_find_entry_idx(c, id, &found);
- if (start == smartlist_len(c->routerstatus_list)) start = 0;
- i = start;
- do {
- routerstatus_t *r = smartlist_get(c->routerstatus_list, i);
- if (r->is_hs_dir) {
- smartlist_add(responsible_dirs, r);
- if (++n_added == REND_NUMBER_OF_CONSECUTIVE_REPLICAS)
- return 0;
- }
- if (++i == smartlist_len(c->routerstatus_list))
- i = 0;
- } while (i != start);
- /* Even though we don't have the desired number of hidden service
- * directories, be happy if we got any. */
- return smartlist_len(responsible_dirs) ? 0 : -1;
- }
- /* Length of the 'extended' auth cookie used to encode auth type before
- * base64 encoding. */
- #define REND_DESC_COOKIE_LEN_EXT (REND_DESC_COOKIE_LEN + 1)
- /* Length of the zero-padded auth cookie when base64 encoded. These two
- * padding bytes always (A=) are stripped off of the returned cookie. */
- #define REND_DESC_COOKIE_LEN_EXT_BASE64 (REND_DESC_COOKIE_LEN_BASE64 + 2)
- /** Encode a client authorization descriptor cookie.
- * The result of this function is suitable for use in the HidServAuth
- * option. The trailing padding characters are removed, and the
- * auth type is encoded into the cookie.
- *
- * Returns a new base64-encoded cookie. This function cannot fail.
- * The caller is responsible for freeing the returned value.
- */
- char *
- rend_auth_encode_cookie(const uint8_t *cookie_in, rend_auth_type_t auth_type)
- {
- uint8_t extended_cookie[REND_DESC_COOKIE_LEN_EXT];
- char *cookie_out = tor_malloc_zero(REND_DESC_COOKIE_LEN_EXT_BASE64 + 1);
- int re;
- tor_assert(cookie_in);
- memcpy(extended_cookie, cookie_in, REND_DESC_COOKIE_LEN);
- extended_cookie[REND_DESC_COOKIE_LEN] = ((int)auth_type - 1) << 4;
- re = base64_encode(cookie_out, REND_DESC_COOKIE_LEN_EXT_BASE64 + 1,
- (const char *) extended_cookie, REND_DESC_COOKIE_LEN_EXT,
- 0);
- tor_assert(re == REND_DESC_COOKIE_LEN_EXT_BASE64);
- /* Remove the trailing 'A='. Auth type is encoded in the high bits
- * of the last byte, so the last base64 character will always be zero
- * (A). This is subtly different behavior from base64_encode_nopad. */
- cookie_out[REND_DESC_COOKIE_LEN_BASE64] = '\0';
- memwipe(extended_cookie, 0, sizeof(extended_cookie));
- return cookie_out;
- }
- /** Decode a base64-encoded client authorization descriptor cookie.
- * The descriptor_cookie can be truncated to REND_DESC_COOKIE_LEN_BASE64
- * characters (as given to clients), or may include the two padding
- * characters (as stored by the service).
- *
- * The result is stored in REND_DESC_COOKIE_LEN bytes of cookie_out.
- * The rend_auth_type_t decoded from the cookie is stored in the
- * optional auth_type_out parameter.
- *
- * Return 0 on success, or -1 on error. The caller is responsible for
- * freeing the returned err_msg.
- */
- int
- rend_auth_decode_cookie(const char *cookie_in, uint8_t *cookie_out,
- rend_auth_type_t *auth_type_out, char **err_msg_out)
- {
- uint8_t descriptor_cookie_decoded[REND_DESC_COOKIE_LEN_EXT + 1] = { 0 };
- char descriptor_cookie_base64ext[REND_DESC_COOKIE_LEN_EXT_BASE64 + 1];
- const char *descriptor_cookie = cookie_in;
- char *err_msg = NULL;
- int auth_type_val = 0;
- int res = -1;
- int decoded_len;
- size_t len = strlen(descriptor_cookie);
- if (len == REND_DESC_COOKIE_LEN_BASE64) {
- /* Add a trailing zero byte to make base64-decoding happy. */
- tor_snprintf(descriptor_cookie_base64ext,
- sizeof(descriptor_cookie_base64ext),
- "%sA=", descriptor_cookie);
- descriptor_cookie = descriptor_cookie_base64ext;
- } else if (len != REND_DESC_COOKIE_LEN_EXT_BASE64) {
- tor_asprintf(&err_msg, "Authorization cookie has wrong length: %s",
- escaped(cookie_in));
- goto err;
- }
- decoded_len = base64_decode((char *) descriptor_cookie_decoded,
- sizeof(descriptor_cookie_decoded),
- descriptor_cookie,
- REND_DESC_COOKIE_LEN_EXT_BASE64);
- if (decoded_len != REND_DESC_COOKIE_LEN &&
- decoded_len != REND_DESC_COOKIE_LEN_EXT) {
- tor_asprintf(&err_msg, "Authorization cookie has invalid characters: %s",
- escaped(cookie_in));
- goto err;
- }
- if (auth_type_out) {
- auth_type_val = (descriptor_cookie_decoded[REND_DESC_COOKIE_LEN] >> 4) + 1;
- if (auth_type_val < 1 || auth_type_val > 2) {
- tor_asprintf(&err_msg, "Authorization cookie type is unknown: %s",
- escaped(cookie_in));
- goto err;
- }
- *auth_type_out = auth_type_val == 1 ? REND_BASIC_AUTH : REND_STEALTH_AUTH;
- }
- memcpy(cookie_out, descriptor_cookie_decoded, REND_DESC_COOKIE_LEN);
- res = 0;
- err:
- if (err_msg_out) {
- *err_msg_out = err_msg;
- } else {
- tor_free(err_msg);
- }
- memwipe(descriptor_cookie_decoded, 0, sizeof(descriptor_cookie_decoded));
- memwipe(descriptor_cookie_base64ext, 0, sizeof(descriptor_cookie_base64ext));
- return res;
- }
- /* Is this a rend client or server that allows direct (non-anonymous)
- * connections?
- * Clients must be specifically compiled and configured in this mode.
- * Onion services can be configured to start in this mode.
- * Prefer rend_client_allow_non_anonymous_connection() or
- * rend_service_allow_non_anonymous_connection() whenever possible, so that
- * checks are specific to Single Onion Services or Tor2web. */
- int
- rend_allow_non_anonymous_connection(const or_options_t* options)
- {
- return (rend_client_allow_non_anonymous_connection(options)
- || rend_service_allow_non_anonymous_connection(options));
- }
- /* Is this a rend client or server in non-anonymous mode?
- * Clients must be specifically compiled in this mode.
- * Onion services can be configured to start in this mode.
- * Prefer rend_client_non_anonymous_mode_enabled() or
- * rend_service_non_anonymous_mode_enabled() whenever possible, so that checks
- * are specific to Single Onion Services or Tor2web. */
- int
- rend_non_anonymous_mode_enabled(const or_options_t *options)
- {
- return (rend_client_non_anonymous_mode_enabled(options)
- || rend_service_non_anonymous_mode_enabled(options));
- }
- /* Make sure that tor only builds one-hop circuits when they would not
- * compromise user anonymity.
- *
- * One-hop circuits are permitted in Tor2web or Single Onion modes.
- *
- * Tor2web or Single Onion modes are also allowed to make multi-hop circuits.
- * For example, single onion HSDir circuits are 3-hop to prevent denial of
- * service.
- */
- void
- assert_circ_anonymity_ok(const origin_circuit_t *circ,
- const or_options_t *options)
- {
- tor_assert(options);
- tor_assert(circ);
- tor_assert(circ->build_state);
- if (circ->build_state->onehop_tunnel) {
- tor_assert(rend_allow_non_anonymous_connection(options));
- }
- }
- /* Return 1 iff the given <b>digest</b> of a permenanent hidden service key is
- * equal to the digest in the origin circuit <b>ocirc</b> of its rend data .
- * If the rend data doesn't exist, 0 is returned. This function is agnostic to
- * the rend data version. */
- int
- rend_circuit_pk_digest_eq(const origin_circuit_t *ocirc,
- const uint8_t *digest)
- {
- size_t rend_pk_digest_len;
- const uint8_t *rend_pk_digest;
- tor_assert(ocirc);
- tor_assert(digest);
- if (ocirc->rend_data == NULL) {
- goto no_match;
- }
- rend_pk_digest = rend_data_get_pk_digest(ocirc->rend_data,
- &rend_pk_digest_len);
- if (tor_memeq(rend_pk_digest, digest, rend_pk_digest_len)) {
- goto match;
- }
- no_match:
- return 0;
- match:
- return 1;
- }
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