rendcache.c 34 KB

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  1. /* Copyright (c) 2015-2017, The Tor Project, Inc. */
  2. /* See LICENSE for licensing information */
  3. /**
  4. * \file rendcache.c
  5. * \brief Hidden service descriptor cache.
  6. **/
  7. #define RENDCACHE_PRIVATE
  8. #include "rendcache.h"
  9. #include "config.h"
  10. #include "rephist.h"
  11. #include "routerlist.h"
  12. #include "routerparse.h"
  13. #include "rendcommon.h"
  14. /** Map from service id (as generated by rend_get_service_id) to
  15. * rend_cache_entry_t. */
  16. STATIC strmap_t *rend_cache = NULL;
  17. /** Map from service id to rend_cache_entry_t; only for hidden services. */
  18. static strmap_t *rend_cache_local_service = NULL;
  19. /** Map from descriptor id to rend_cache_entry_t; only for hidden service
  20. * directories. */
  21. STATIC digestmap_t *rend_cache_v2_dir = NULL;
  22. /** (Client side only) Map from service id to rend_cache_failure_t. This
  23. * cache is used to track intro point(IP) failures so we know when to keep
  24. * or discard a new descriptor we just fetched. Here is a description of the
  25. * cache behavior.
  26. *
  27. * Everytime tor discards an IP (ex: receives a NACK), we add an entry to
  28. * this cache noting the identity digest of the IP and it's failure type for
  29. * the service ID. The reason we indexed this cache by service ID is to
  30. * differentiate errors that can occur only for a specific service like a
  31. * NACK for instance. It applies for one but maybe not for the others.
  32. *
  33. * Once a service descriptor is fetched and considered valid, each IP is
  34. * looked up in this cache and if present, it is discarded from the fetched
  35. * descriptor. At the end, all IP(s) in the cache, for a specific service
  36. * ID, that were NOT present in the descriptor are removed from this cache.
  37. * Which means that if at least one IP was not in this cache, thus usuable,
  38. * it's considered a new descriptor so we keep it. Else, if all IPs were in
  39. * this cache, we discard the descriptor as it's considered unusable.
  40. *
  41. * Once a descriptor is removed from the rend cache or expires, the entry
  42. * in this cache is also removed for the service ID.
  43. *
  44. * This scheme allows us to not relay on the descriptor's timestamp (which
  45. * is rounded down to the hour) to know if we have a newer descriptor. We
  46. * only rely on the usability of intro points from an internal state. */
  47. STATIC strmap_t *rend_cache_failure = NULL;
  48. /* DOCDOC */
  49. STATIC size_t rend_cache_total_allocation = 0;
  50. /** Initializes the service descriptor cache.
  51. */
  52. void
  53. rend_cache_init(void)
  54. {
  55. rend_cache = strmap_new();
  56. rend_cache_v2_dir = digestmap_new();
  57. rend_cache_local_service = strmap_new();
  58. rend_cache_failure = strmap_new();
  59. }
  60. /** Return the approximate number of bytes needed to hold <b>e</b>. */
  61. STATIC size_t
  62. rend_cache_entry_allocation(const rend_cache_entry_t *e)
  63. {
  64. if (!e)
  65. return 0;
  66. /* This doesn't count intro_nodes or key size */
  67. return sizeof(*e) + e->len + sizeof(*e->parsed);
  68. }
  69. /* DOCDOC */
  70. size_t
  71. rend_cache_get_total_allocation(void)
  72. {
  73. return rend_cache_total_allocation;
  74. }
  75. /** Decrement the total bytes attributed to the rendezvous cache by n. */
  76. void
  77. rend_cache_decrement_allocation(size_t n)
  78. {
  79. static int have_underflowed = 0;
  80. if (rend_cache_total_allocation >= n) {
  81. rend_cache_total_allocation -= n;
  82. } else {
  83. rend_cache_total_allocation = 0;
  84. if (! have_underflowed) {
  85. have_underflowed = 1;
  86. log_warn(LD_BUG, "Underflow in rend_cache_decrement_allocation");
  87. }
  88. }
  89. }
  90. /** Increase the total bytes attributed to the rendezvous cache by n. */
  91. void
  92. rend_cache_increment_allocation(size_t n)
  93. {
  94. static int have_overflowed = 0;
  95. if (rend_cache_total_allocation <= SIZE_MAX - n) {
  96. rend_cache_total_allocation += n;
  97. } else {
  98. rend_cache_total_allocation = SIZE_MAX;
  99. if (! have_overflowed) {
  100. have_overflowed = 1;
  101. log_warn(LD_BUG, "Overflow in rend_cache_increment_allocation");
  102. }
  103. }
  104. }
  105. /** Helper: free a rend cache failure intro object. */
  106. STATIC void
  107. rend_cache_failure_intro_entry_free_(rend_cache_failure_intro_t *entry)
  108. {
  109. if (entry == NULL) {
  110. return;
  111. }
  112. tor_free(entry);
  113. }
  114. static void
  115. rend_cache_failure_intro_entry_free_void(void *entry)
  116. {
  117. rend_cache_failure_intro_entry_free_(entry);
  118. }
  119. /** Allocate a rend cache failure intro object and return it. <b>failure</b>
  120. * is set into the object. This function can not fail. */
  121. STATIC rend_cache_failure_intro_t *
  122. rend_cache_failure_intro_entry_new(rend_intro_point_failure_t failure)
  123. {
  124. rend_cache_failure_intro_t *entry = tor_malloc(sizeof(*entry));
  125. entry->failure_type = failure;
  126. entry->created_ts = time(NULL);
  127. return entry;
  128. }
  129. /** Helper: free a rend cache failure object. */
  130. STATIC void
  131. rend_cache_failure_entry_free_(rend_cache_failure_t *entry)
  132. {
  133. if (entry == NULL) {
  134. return;
  135. }
  136. /* Free and remove every intro failure object. */
  137. digestmap_free(entry->intro_failures,
  138. rend_cache_failure_intro_entry_free_void);
  139. tor_free(entry);
  140. }
  141. /** Helper: deallocate a rend_cache_failure_t. (Used with strmap_free(),
  142. * which requires a function pointer whose argument is void*). */
  143. STATIC void
  144. rend_cache_failure_entry_free_void(void *entry)
  145. {
  146. rend_cache_failure_entry_free_(entry);
  147. }
  148. /** Allocate a rend cache failure object and return it. This function can
  149. * not fail. */
  150. STATIC rend_cache_failure_t *
  151. rend_cache_failure_entry_new(void)
  152. {
  153. rend_cache_failure_t *entry = tor_malloc(sizeof(*entry));
  154. entry->intro_failures = digestmap_new();
  155. return entry;
  156. }
  157. /** Remove failure cache entry for the service ID in the given descriptor
  158. * <b>desc</b>. */
  159. STATIC void
  160. rend_cache_failure_remove(rend_service_descriptor_t *desc)
  161. {
  162. char service_id[REND_SERVICE_ID_LEN_BASE32 + 1];
  163. rend_cache_failure_t *entry;
  164. if (desc == NULL) {
  165. return;
  166. }
  167. if (rend_get_service_id(desc->pk, service_id) < 0) {
  168. return;
  169. }
  170. entry = strmap_get_lc(rend_cache_failure, service_id);
  171. if (entry != NULL) {
  172. strmap_remove_lc(rend_cache_failure, service_id);
  173. rend_cache_failure_entry_free(entry);
  174. }
  175. }
  176. /** Helper: free storage held by a single service descriptor cache entry. */
  177. STATIC void
  178. rend_cache_entry_free_(rend_cache_entry_t *e)
  179. {
  180. if (!e)
  181. return;
  182. rend_cache_decrement_allocation(rend_cache_entry_allocation(e));
  183. /* We are about to remove a descriptor from the cache so remove the entry
  184. * in the failure cache. */
  185. rend_cache_failure_remove(e->parsed);
  186. rend_service_descriptor_free(e->parsed);
  187. tor_free(e->desc);
  188. tor_free(e);
  189. }
  190. /** Helper: deallocate a rend_cache_entry_t. (Used with strmap_free(), which
  191. * requires a function pointer whose argument is void*). */
  192. static void
  193. rend_cache_entry_free_void(void *p)
  194. {
  195. rend_cache_entry_free_(p);
  196. }
  197. /** Free all storage held by the service descriptor cache. */
  198. void
  199. rend_cache_free_all(void)
  200. {
  201. strmap_free(rend_cache, rend_cache_entry_free_void);
  202. digestmap_free(rend_cache_v2_dir, rend_cache_entry_free_void);
  203. strmap_free(rend_cache_local_service, rend_cache_entry_free_void);
  204. strmap_free(rend_cache_failure, rend_cache_failure_entry_free_void);
  205. rend_cache = NULL;
  206. rend_cache_v2_dir = NULL;
  207. rend_cache_local_service = NULL;
  208. rend_cache_failure = NULL;
  209. rend_cache_total_allocation = 0;
  210. }
  211. /** Remove all entries that re REND_CACHE_FAILURE_MAX_AGE old. This is
  212. * called every second.
  213. *
  214. * We have to clean these regurlarly else if for whatever reasons an hidden
  215. * service goes offline and a client tries to connect to it during that
  216. * time, a failure entry is created and the client will be unable to connect
  217. * for a while even though the service has return online. */
  218. void
  219. rend_cache_failure_clean(time_t now)
  220. {
  221. time_t cutoff = now - REND_CACHE_FAILURE_MAX_AGE;
  222. STRMAP_FOREACH_MODIFY(rend_cache_failure, key,
  223. rend_cache_failure_t *, ent) {
  224. /* Free and remove every intro failure object that match the cutoff. */
  225. DIGESTMAP_FOREACH_MODIFY(ent->intro_failures, ip_key,
  226. rend_cache_failure_intro_t *, ip_ent) {
  227. if (ip_ent->created_ts < cutoff) {
  228. rend_cache_failure_intro_entry_free(ip_ent);
  229. MAP_DEL_CURRENT(ip_key);
  230. }
  231. } DIGESTMAP_FOREACH_END;
  232. /* If the entry is now empty of intro point failures, remove it. */
  233. if (digestmap_isempty(ent->intro_failures)) {
  234. rend_cache_failure_entry_free(ent);
  235. MAP_DEL_CURRENT(key);
  236. }
  237. } STRMAP_FOREACH_END;
  238. }
  239. /** Removes all old entries from the client or service descriptor cache.
  240. */
  241. void
  242. rend_cache_clean(time_t now, rend_cache_type_t cache_type)
  243. {
  244. strmap_iter_t *iter;
  245. const char *key;
  246. void *val;
  247. rend_cache_entry_t *ent;
  248. time_t cutoff = now - REND_CACHE_MAX_AGE - REND_CACHE_MAX_SKEW;
  249. strmap_t *cache = NULL;
  250. if (cache_type == REND_CACHE_TYPE_CLIENT) {
  251. cache = rend_cache;
  252. } else if (cache_type == REND_CACHE_TYPE_SERVICE) {
  253. cache = rend_cache_local_service;
  254. }
  255. tor_assert(cache);
  256. for (iter = strmap_iter_init(cache); !strmap_iter_done(iter); ) {
  257. strmap_iter_get(iter, &key, &val);
  258. ent = (rend_cache_entry_t*)val;
  259. if (ent->parsed->timestamp < cutoff) {
  260. iter = strmap_iter_next_rmv(cache, iter);
  261. rend_cache_entry_free(ent);
  262. } else {
  263. iter = strmap_iter_next(cache, iter);
  264. }
  265. }
  266. }
  267. /** Remove ALL entries from the rendezvous service descriptor cache.
  268. */
  269. void
  270. rend_cache_purge(void)
  271. {
  272. if (rend_cache) {
  273. log_info(LD_REND, "Purging HS v2 descriptor cache");
  274. strmap_free(rend_cache, rend_cache_entry_free_void);
  275. }
  276. rend_cache = strmap_new();
  277. }
  278. /** Remove ALL entries from the failure cache. This is also called when a
  279. * NEWNYM signal is received. */
  280. void
  281. rend_cache_failure_purge(void)
  282. {
  283. if (rend_cache_failure) {
  284. log_info(LD_REND, "Purging HS v2 failure cache");
  285. strmap_free(rend_cache_failure, rend_cache_failure_entry_free_void);
  286. }
  287. rend_cache_failure = strmap_new();
  288. }
  289. /** Lookup the rend failure cache using a relay identity digest in
  290. * <b>identity</b> which has DIGEST_LEN bytes and service ID <b>service_id</b>
  291. * which is a null-terminated string. If found, the intro failure is set in
  292. * <b>intro_entry</b> else it stays untouched. Return 1 iff found else 0. */
  293. STATIC int
  294. cache_failure_intro_lookup(const uint8_t *identity, const char *service_id,
  295. rend_cache_failure_intro_t **intro_entry)
  296. {
  297. rend_cache_failure_t *elem;
  298. rend_cache_failure_intro_t *intro_elem;
  299. tor_assert(rend_cache_failure);
  300. if (intro_entry) {
  301. *intro_entry = NULL;
  302. }
  303. /* Lookup descriptor and return it. */
  304. elem = strmap_get_lc(rend_cache_failure, service_id);
  305. if (elem == NULL) {
  306. goto not_found;
  307. }
  308. intro_elem = digestmap_get(elem->intro_failures, (char *) identity);
  309. if (intro_elem == NULL) {
  310. goto not_found;
  311. }
  312. if (intro_entry) {
  313. *intro_entry = intro_elem;
  314. }
  315. return 1;
  316. not_found:
  317. return 0;
  318. }
  319. /** Allocate a new cache failure intro object and copy the content from
  320. * <b>entry</b> to this newly allocated object. Return it. */
  321. static rend_cache_failure_intro_t *
  322. cache_failure_intro_dup(const rend_cache_failure_intro_t *entry)
  323. {
  324. rend_cache_failure_intro_t *ent_dup =
  325. rend_cache_failure_intro_entry_new(entry->failure_type);
  326. ent_dup->created_ts = entry->created_ts;
  327. return ent_dup;
  328. }
  329. /** Add an intro point failure to the failure cache using the relay
  330. * <b>identity</b> and service ID <b>service_id</b>. Record the
  331. * <b>failure</b> in that object. */
  332. STATIC void
  333. cache_failure_intro_add(const uint8_t *identity, const char *service_id,
  334. rend_intro_point_failure_t failure)
  335. {
  336. rend_cache_failure_t *fail_entry;
  337. rend_cache_failure_intro_t *entry, *old_entry;
  338. /* Make sure we have a failure object for this service ID and if not,
  339. * create it with this new intro failure entry. */
  340. fail_entry = strmap_get_lc(rend_cache_failure, service_id);
  341. if (fail_entry == NULL) {
  342. fail_entry = rend_cache_failure_entry_new();
  343. /* Add failure entry to global rend failure cache. */
  344. strmap_set_lc(rend_cache_failure, service_id, fail_entry);
  345. }
  346. entry = rend_cache_failure_intro_entry_new(failure);
  347. old_entry = digestmap_set(fail_entry->intro_failures,
  348. (char *) identity, entry);
  349. /* This _should_ be NULL, but in case it isn't, free it. */
  350. rend_cache_failure_intro_entry_free(old_entry);
  351. }
  352. /** Using a parsed descriptor <b>desc</b>, check if the introduction points
  353. * are present in the failure cache and if so they are removed from the
  354. * descriptor and kept into the failure cache. Then, each intro points that
  355. * are NOT in the descriptor but in the failure cache for the given
  356. * <b>service_id</b> are removed from the failure cache. */
  357. STATIC void
  358. validate_intro_point_failure(const rend_service_descriptor_t *desc,
  359. const char *service_id)
  360. {
  361. rend_cache_failure_t *new_entry, *cur_entry;
  362. /* New entry for the service ID that will be replacing the one in the
  363. * failure cache since we have a new descriptor. In the case where all
  364. * intro points are removed, we are assured that the new entry is the same
  365. * as the current one. */
  366. new_entry = tor_malloc(sizeof(*new_entry));
  367. new_entry->intro_failures = digestmap_new();
  368. tor_assert(desc);
  369. SMARTLIST_FOREACH_BEGIN(desc->intro_nodes, rend_intro_point_t *, intro) {
  370. int found;
  371. rend_cache_failure_intro_t *entry;
  372. const uint8_t *identity =
  373. (uint8_t *) intro->extend_info->identity_digest;
  374. found = cache_failure_intro_lookup(identity, service_id, &entry);
  375. if (found) {
  376. /* Dup here since it will be freed at the end when removing the
  377. * original entry in the cache. */
  378. rend_cache_failure_intro_t *ent_dup = cache_failure_intro_dup(entry);
  379. /* This intro point is in our cache, discard it from the descriptor
  380. * because chances are that it's unusable. */
  381. SMARTLIST_DEL_CURRENT(desc->intro_nodes, intro);
  382. /* Keep it for our new entry. */
  383. digestmap_set(new_entry->intro_failures, (char *) identity, ent_dup);
  384. /* Only free it when we're done looking at it. */
  385. rend_intro_point_free(intro);
  386. continue;
  387. }
  388. } SMARTLIST_FOREACH_END(intro);
  389. /* Swap the failure entry in the cache and free the current one. */
  390. cur_entry = strmap_get_lc(rend_cache_failure, service_id);
  391. if (cur_entry != NULL) {
  392. rend_cache_failure_entry_free(cur_entry);
  393. }
  394. strmap_set_lc(rend_cache_failure, service_id, new_entry);
  395. }
  396. /** Note down an intro failure in the rend failure cache using the type of
  397. * failure in <b>failure</b> for the relay identity digest in
  398. * <b>identity</b> and service ID <b>service_id</b>. If an entry already
  399. * exists in the cache, the failure type is changed with <b>failure</b>. */
  400. void
  401. rend_cache_intro_failure_note(rend_intro_point_failure_t failure,
  402. const uint8_t *identity,
  403. const char *service_id)
  404. {
  405. int found;
  406. rend_cache_failure_intro_t *entry;
  407. found = cache_failure_intro_lookup(identity, service_id, &entry);
  408. if (!found) {
  409. cache_failure_intro_add(identity, service_id, failure);
  410. } else {
  411. /* Replace introduction point failure with this one. */
  412. entry->failure_type = failure;
  413. }
  414. }
  415. /** Remove all old v2 descriptors and those for which this hidden service
  416. * directory is not responsible for any more. The cutoff is the time limit for
  417. * which we want to keep the cache entry. In other words, any entry created
  418. * before will be removed. */
  419. size_t
  420. rend_cache_clean_v2_descs_as_dir(time_t cutoff)
  421. {
  422. digestmap_iter_t *iter;
  423. size_t bytes_removed = 0;
  424. for (iter = digestmap_iter_init(rend_cache_v2_dir);
  425. !digestmap_iter_done(iter); ) {
  426. const char *key;
  427. void *val;
  428. rend_cache_entry_t *ent;
  429. digestmap_iter_get(iter, &key, &val);
  430. ent = val;
  431. if (ent->parsed->timestamp < cutoff) {
  432. char key_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
  433. base32_encode(key_base32, sizeof(key_base32), key, DIGEST_LEN);
  434. log_info(LD_REND, "Removing descriptor with ID '%s' from cache",
  435. safe_str_client(key_base32));
  436. bytes_removed += rend_cache_entry_allocation(ent);
  437. iter = digestmap_iter_next_rmv(rend_cache_v2_dir, iter);
  438. rend_cache_entry_free(ent);
  439. } else {
  440. iter = digestmap_iter_next(rend_cache_v2_dir, iter);
  441. }
  442. }
  443. return bytes_removed;
  444. }
  445. /** Lookup in the client cache the given service ID <b>query</b> for
  446. * <b>version</b>.
  447. *
  448. * Return 0 if found and if <b>e</b> is non NULL, set it with the entry
  449. * found. Else, a negative value is returned and <b>e</b> is untouched.
  450. * -EINVAL means that <b>query</b> is not a valid service id.
  451. * -ENOENT means that no entry in the cache was found. */
  452. int
  453. rend_cache_lookup_entry(const char *query, int version, rend_cache_entry_t **e)
  454. {
  455. int ret = 0;
  456. char key[REND_SERVICE_ID_LEN_BASE32 + 2]; /* <version><query>\0 */
  457. rend_cache_entry_t *entry = NULL;
  458. static const int default_version = 2;
  459. tor_assert(rend_cache);
  460. tor_assert(query);
  461. if (!rend_valid_v2_service_id(query)) {
  462. ret = -EINVAL;
  463. goto end;
  464. }
  465. switch (version) {
  466. case 0:
  467. log_warn(LD_REND, "Cache lookup of a v0 renddesc is deprecated.");
  468. break;
  469. case 2:
  470. /* Default is version 2. */
  471. default:
  472. tor_snprintf(key, sizeof(key), "%d%s", default_version, query);
  473. entry = strmap_get_lc(rend_cache, key);
  474. break;
  475. }
  476. if (!entry) {
  477. ret = -ENOENT;
  478. goto end;
  479. }
  480. tor_assert(entry->parsed && entry->parsed->intro_nodes);
  481. if (e) {
  482. *e = entry;
  483. }
  484. end:
  485. return ret;
  486. }
  487. /*
  488. * Lookup the v2 service descriptor with the service ID <b>query</b> in the
  489. * local service descriptor cache. Return 0 if found and if <b>e</b> is
  490. * non NULL, set it with the entry found. Else, a negative value is returned
  491. * and <b>e</b> is untouched.
  492. * -EINVAL means that <b>query</b> is not a valid service id.
  493. * -ENOENT means that no entry in the cache was found. */
  494. int
  495. rend_cache_lookup_v2_desc_as_service(const char *query, rend_cache_entry_t **e)
  496. {
  497. int ret = 0;
  498. rend_cache_entry_t *entry = NULL;
  499. tor_assert(rend_cache_local_service);
  500. tor_assert(query);
  501. if (!rend_valid_v2_service_id(query)) {
  502. ret = -EINVAL;
  503. goto end;
  504. }
  505. /* Lookup descriptor and return. */
  506. entry = strmap_get_lc(rend_cache_local_service, query);
  507. if (!entry) {
  508. ret = -ENOENT;
  509. goto end;
  510. }
  511. if (e) {
  512. *e = entry;
  513. }
  514. end:
  515. return ret;
  516. }
  517. /** Lookup the v2 service descriptor with base32-encoded <b>desc_id</b> and
  518. * copy the pointer to it to *<b>desc</b>. Return 1 on success, 0 on
  519. * well-formed-but-not-found, and -1 on failure.
  520. */
  521. int
  522. rend_cache_lookup_v2_desc_as_dir(const char *desc_id, const char **desc)
  523. {
  524. rend_cache_entry_t *e;
  525. char desc_id_digest[DIGEST_LEN];
  526. tor_assert(rend_cache_v2_dir);
  527. if (base32_decode(desc_id_digest, DIGEST_LEN,
  528. desc_id, REND_DESC_ID_V2_LEN_BASE32) < 0) {
  529. log_fn(LOG_PROTOCOL_WARN, LD_REND,
  530. "Rejecting v2 rendezvous descriptor request -- descriptor ID "
  531. "contains illegal characters: %s",
  532. safe_str(desc_id));
  533. return -1;
  534. }
  535. /* Lookup descriptor and return. */
  536. e = digestmap_get(rend_cache_v2_dir, desc_id_digest);
  537. if (e) {
  538. *desc = e->desc;
  539. e->last_served = approx_time();
  540. return 1;
  541. }
  542. return 0;
  543. }
  544. /** Parse the v2 service descriptor(s) in <b>desc</b> and store it/them to the
  545. * local rend cache. Don't attempt to decrypt the included list of introduction
  546. * points (as we don't have a descriptor cookie for it).
  547. *
  548. * If we have a newer descriptor with the same ID, ignore this one.
  549. * If we have an older descriptor with the same ID, replace it.
  550. *
  551. * Return 0 on success, or -1 if we couldn't parse any of them.
  552. *
  553. * We should only call this function for public (e.g. non bridge) relays.
  554. */
  555. int
  556. rend_cache_store_v2_desc_as_dir(const char *desc)
  557. {
  558. const or_options_t *options = get_options();
  559. rend_service_descriptor_t *parsed;
  560. char desc_id[DIGEST_LEN];
  561. char *intro_content;
  562. size_t intro_size;
  563. size_t encoded_size;
  564. char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
  565. int number_parsed = 0, number_stored = 0;
  566. const char *current_desc = desc;
  567. const char *next_desc;
  568. rend_cache_entry_t *e;
  569. time_t now = time(NULL);
  570. tor_assert(rend_cache_v2_dir);
  571. tor_assert(desc);
  572. while (rend_parse_v2_service_descriptor(&parsed, desc_id, &intro_content,
  573. &intro_size, &encoded_size,
  574. &next_desc, current_desc, 1) >= 0) {
  575. number_parsed++;
  576. /* We don't care about the introduction points. */
  577. tor_free(intro_content);
  578. /* For pretty log statements. */
  579. base32_encode(desc_id_base32, sizeof(desc_id_base32),
  580. desc_id, DIGEST_LEN);
  581. /* Is descriptor too old? */
  582. if (parsed->timestamp < now - REND_CACHE_MAX_AGE-REND_CACHE_MAX_SKEW) {
  583. log_info(LD_REND, "Service descriptor with desc ID %s is too old.",
  584. safe_str(desc_id_base32));
  585. goto skip;
  586. }
  587. /* Is descriptor too far in the future? */
  588. if (parsed->timestamp > now + REND_CACHE_MAX_SKEW) {
  589. log_info(LD_REND, "Service descriptor with desc ID %s is too far in the "
  590. "future.",
  591. safe_str(desc_id_base32));
  592. goto skip;
  593. }
  594. /* Do we already have a newer descriptor? */
  595. e = digestmap_get(rend_cache_v2_dir, desc_id);
  596. if (e && e->parsed->timestamp > parsed->timestamp) {
  597. log_info(LD_REND, "We already have a newer service descriptor with the "
  598. "same desc ID %s and version.",
  599. safe_str(desc_id_base32));
  600. goto skip;
  601. }
  602. /* Do we already have this descriptor? */
  603. if (e && !strcmp(desc, e->desc)) {
  604. log_info(LD_REND, "We already have this service descriptor with desc "
  605. "ID %s.", safe_str(desc_id_base32));
  606. goto skip;
  607. }
  608. /* Store received descriptor. */
  609. if (!e) {
  610. e = tor_malloc_zero(sizeof(rend_cache_entry_t));
  611. digestmap_set(rend_cache_v2_dir, desc_id, e);
  612. /* Treat something just uploaded as having been served a little
  613. * while ago, so that flooding with new descriptors doesn't help
  614. * too much.
  615. */
  616. e->last_served = approx_time() - 3600;
  617. } else {
  618. rend_cache_decrement_allocation(rend_cache_entry_allocation(e));
  619. rend_service_descriptor_free(e->parsed);
  620. tor_free(e->desc);
  621. }
  622. e->parsed = parsed;
  623. e->desc = tor_strndup(current_desc, encoded_size);
  624. e->len = encoded_size;
  625. rend_cache_increment_allocation(rend_cache_entry_allocation(e));
  626. log_info(LD_REND, "Successfully stored service descriptor with desc ID "
  627. "'%s' and len %d.",
  628. safe_str(desc_id_base32), (int)encoded_size);
  629. /* Statistics: Note down this potentially new HS. */
  630. if (options->HiddenServiceStatistics) {
  631. rep_hist_stored_maybe_new_hs(e->parsed->pk);
  632. }
  633. number_stored++;
  634. goto advance;
  635. skip:
  636. rend_service_descriptor_free(parsed);
  637. advance:
  638. /* advance to next descriptor, if available. */
  639. current_desc = next_desc;
  640. /* check if there is a next descriptor. */
  641. if (!current_desc ||
  642. strcmpstart(current_desc, "rendezvous-service-descriptor "))
  643. break;
  644. }
  645. if (!number_parsed) {
  646. log_info(LD_REND, "Could not parse any descriptor.");
  647. return -1;
  648. }
  649. log_info(LD_REND, "Parsed %d and added %d descriptor%s.",
  650. number_parsed, number_stored, number_stored != 1 ? "s" : "");
  651. return 0;
  652. }
  653. /** Parse the v2 service descriptor in <b>desc</b> and store it to the
  654. * local service rend cache. Don't attempt to decrypt the included list of
  655. * introduction points.
  656. *
  657. * If we have a newer descriptor with the same ID, ignore this one.
  658. * If we have an older descriptor with the same ID, replace it.
  659. *
  660. * Return 0 on success, or -1 if we couldn't understand the descriptor.
  661. */
  662. int
  663. rend_cache_store_v2_desc_as_service(const char *desc)
  664. {
  665. rend_service_descriptor_t *parsed = NULL;
  666. char desc_id[DIGEST_LEN];
  667. char *intro_content = NULL;
  668. size_t intro_size;
  669. size_t encoded_size;
  670. const char *next_desc;
  671. char service_id[REND_SERVICE_ID_LEN_BASE32+1];
  672. rend_cache_entry_t *e;
  673. int retval = -1;
  674. tor_assert(rend_cache_local_service);
  675. tor_assert(desc);
  676. /* Parse the descriptor. */
  677. if (rend_parse_v2_service_descriptor(&parsed, desc_id, &intro_content,
  678. &intro_size, &encoded_size,
  679. &next_desc, desc, 0) < 0) {
  680. log_warn(LD_REND, "Could not parse descriptor.");
  681. goto err;
  682. }
  683. /* Compute service ID from public key. */
  684. if (rend_get_service_id(parsed->pk, service_id)<0) {
  685. log_warn(LD_REND, "Couldn't compute service ID.");
  686. goto err;
  687. }
  688. /* Do we already have a newer descriptor? Allow new descriptors with a
  689. rounded timestamp equal to or newer than the current descriptor */
  690. e = (rend_cache_entry_t*) strmap_get_lc(rend_cache_local_service,
  691. service_id);
  692. if (e && e->parsed->timestamp > parsed->timestamp) {
  693. log_info(LD_REND, "We already have a newer service descriptor for "
  694. "service ID %s.", safe_str_client(service_id));
  695. goto okay;
  696. }
  697. /* We don't care about the introduction points. */
  698. tor_free(intro_content);
  699. if (!e) {
  700. e = tor_malloc_zero(sizeof(rend_cache_entry_t));
  701. strmap_set_lc(rend_cache_local_service, service_id, e);
  702. } else {
  703. rend_cache_decrement_allocation(rend_cache_entry_allocation(e));
  704. rend_service_descriptor_free(e->parsed);
  705. tor_free(e->desc);
  706. }
  707. e->parsed = parsed;
  708. e->desc = tor_malloc_zero(encoded_size + 1);
  709. strlcpy(e->desc, desc, encoded_size + 1);
  710. e->len = encoded_size;
  711. rend_cache_increment_allocation(rend_cache_entry_allocation(e));
  712. log_debug(LD_REND,"Successfully stored rend desc '%s', len %d.",
  713. safe_str_client(service_id), (int)encoded_size);
  714. return 0;
  715. okay:
  716. retval = 0;
  717. err:
  718. rend_service_descriptor_free(parsed);
  719. tor_free(intro_content);
  720. return retval;
  721. }
  722. /** Parse the v2 service descriptor in <b>desc</b>, decrypt the included list
  723. * of introduction points with <b>descriptor_cookie</b> (which may also be
  724. * <b>NULL</b> if decryption is not necessary), and store the descriptor to
  725. * the local cache under its version and service id.
  726. *
  727. * If we have a newer v2 descriptor with the same ID, ignore this one.
  728. * If we have an older descriptor with the same ID, replace it.
  729. * If the descriptor's service ID does not match
  730. * <b>rend_query</b>-\>onion_address, reject it.
  731. *
  732. * If the descriptor's descriptor ID doesn't match <b>desc_id_base32</b>,
  733. * reject it.
  734. *
  735. * Return 0 on success, or -1 if we rejected the descriptor.
  736. * If entry is not NULL, set it with the cache entry pointer of the descriptor.
  737. */
  738. int
  739. rend_cache_store_v2_desc_as_client(const char *desc,
  740. const char *desc_id_base32,
  741. const rend_data_t *rend_query,
  742. rend_cache_entry_t **entry)
  743. {
  744. /*XXXX this seems to have a bit of duplicate code with
  745. * rend_cache_store_v2_desc_as_dir(). Fix that. */
  746. /* Though having similar elements, both functions were separated on
  747. * purpose:
  748. * - dirs don't care about encoded/encrypted introduction points, clients
  749. * do.
  750. * - dirs store descriptors in a separate cache by descriptor ID, whereas
  751. * clients store them by service ID; both caches are different data
  752. * structures and have different access methods.
  753. * - dirs store a descriptor only if they are responsible for its ID,
  754. * clients do so in every way (because they have requested it before).
  755. * - dirs can process multiple concatenated descriptors which is required
  756. * for replication, whereas clients only accept a single descriptor.
  757. * Thus, combining both methods would result in a lot of if statements
  758. * which probably would not improve, but worsen code readability. -KL */
  759. rend_service_descriptor_t *parsed = NULL;
  760. char desc_id[DIGEST_LEN];
  761. char *intro_content = NULL;
  762. size_t intro_size;
  763. size_t encoded_size;
  764. const char *next_desc;
  765. time_t now = time(NULL);
  766. char key[REND_SERVICE_ID_LEN_BASE32+2];
  767. char service_id[REND_SERVICE_ID_LEN_BASE32+1];
  768. char want_desc_id[DIGEST_LEN];
  769. rend_cache_entry_t *e;
  770. int retval = -1;
  771. rend_data_v2_t *rend_data = TO_REND_DATA_V2(rend_query);
  772. tor_assert(rend_cache);
  773. tor_assert(desc);
  774. tor_assert(desc_id_base32);
  775. memset(want_desc_id, 0, sizeof(want_desc_id));
  776. if (entry) {
  777. *entry = NULL;
  778. }
  779. if (base32_decode(want_desc_id, sizeof(want_desc_id),
  780. desc_id_base32, strlen(desc_id_base32)) != 0) {
  781. log_warn(LD_BUG, "Couldn't decode base32 %s for descriptor id.",
  782. escaped_safe_str_client(desc_id_base32));
  783. goto err;
  784. }
  785. /* Parse the descriptor. */
  786. if (rend_parse_v2_service_descriptor(&parsed, desc_id, &intro_content,
  787. &intro_size, &encoded_size,
  788. &next_desc, desc, 0) < 0) {
  789. log_warn(LD_REND, "Could not parse descriptor.");
  790. goto err;
  791. }
  792. /* Compute service ID from public key. */
  793. if (rend_get_service_id(parsed->pk, service_id)<0) {
  794. log_warn(LD_REND, "Couldn't compute service ID.");
  795. goto err;
  796. }
  797. if (rend_data->onion_address[0] != '\0' &&
  798. strcmp(rend_data->onion_address, service_id)) {
  799. log_warn(LD_REND, "Received service descriptor for service ID %s; "
  800. "expected descriptor for service ID %s.",
  801. service_id, safe_str(rend_data->onion_address));
  802. goto err;
  803. }
  804. if (tor_memneq(desc_id, want_desc_id, DIGEST_LEN)) {
  805. log_warn(LD_REND, "Received service descriptor for %s with incorrect "
  806. "descriptor ID.", service_id);
  807. goto err;
  808. }
  809. /* Decode/decrypt introduction points. */
  810. if (intro_content && intro_size > 0) {
  811. int n_intro_points;
  812. if (rend_data->auth_type != REND_NO_AUTH &&
  813. !tor_mem_is_zero(rend_data->descriptor_cookie,
  814. sizeof(rend_data->descriptor_cookie))) {
  815. char *ipos_decrypted = NULL;
  816. size_t ipos_decrypted_size;
  817. if (rend_decrypt_introduction_points(&ipos_decrypted,
  818. &ipos_decrypted_size,
  819. rend_data->descriptor_cookie,
  820. intro_content,
  821. intro_size) < 0) {
  822. log_warn(LD_REND, "Failed to decrypt introduction points. We are "
  823. "probably unable to parse the encoded introduction points.");
  824. } else {
  825. /* Replace encrypted with decrypted introduction points. */
  826. log_info(LD_REND, "Successfully decrypted introduction points.");
  827. tor_free(intro_content);
  828. intro_content = ipos_decrypted;
  829. intro_size = ipos_decrypted_size;
  830. }
  831. }
  832. n_intro_points = rend_parse_introduction_points(parsed, intro_content,
  833. intro_size);
  834. if (n_intro_points <= 0) {
  835. log_warn(LD_REND, "Failed to parse introduction points. Either the "
  836. "service has published a corrupt descriptor or you have "
  837. "provided invalid authorization data, or (maybe!) the "
  838. "server is deliberately serving broken data in an attempt "
  839. "to crash you with bug 21018.");
  840. goto err;
  841. } else if (n_intro_points > MAX_INTRO_POINTS) {
  842. log_warn(LD_REND, "Found too many introduction points on a hidden "
  843. "service descriptor for %s. This is probably a (misguided) "
  844. "attempt to improve reliability, but it could also be an "
  845. "attempt to do a guard enumeration attack. Rejecting.",
  846. safe_str_client(service_id));
  847. goto err;
  848. }
  849. } else {
  850. log_info(LD_REND, "Descriptor does not contain any introduction points.");
  851. parsed->intro_nodes = smartlist_new();
  852. }
  853. /* We don't need the encoded/encrypted introduction points any longer. */
  854. tor_free(intro_content);
  855. /* Is descriptor too old? */
  856. if (parsed->timestamp < now - REND_CACHE_MAX_AGE-REND_CACHE_MAX_SKEW) {
  857. log_warn(LD_REND, "Service descriptor with service ID %s is too old.",
  858. safe_str_client(service_id));
  859. goto err;
  860. }
  861. /* Is descriptor too far in the future? */
  862. if (parsed->timestamp > now + REND_CACHE_MAX_SKEW) {
  863. log_warn(LD_REND, "Service descriptor with service ID %s is too far in "
  864. "the future.", safe_str_client(service_id));
  865. goto err;
  866. }
  867. /* Do we have the same exact copy already in our cache? */
  868. tor_snprintf(key, sizeof(key), "2%s", service_id);
  869. e = (rend_cache_entry_t*) strmap_get_lc(rend_cache, key);
  870. if (e && !strcmp(desc, e->desc)) {
  871. log_info(LD_REND,"We already have this service descriptor %s.",
  872. safe_str_client(service_id));
  873. goto okay;
  874. }
  875. /* Verify that we are not replacing an older descriptor. It's important to
  876. * avoid an evil HSDir serving old descriptor. We validate if the
  877. * timestamp is greater than and not equal because it's a rounded down
  878. * timestamp to the hour so if the descriptor changed in the same hour,
  879. * the rend cache failure will tell us if we have a new descriptor. */
  880. if (e && e->parsed->timestamp > parsed->timestamp) {
  881. log_info(LD_REND, "We already have a new enough service descriptor for "
  882. "service ID %s with the same desc ID and version.",
  883. safe_str_client(service_id));
  884. goto okay;
  885. }
  886. /* Lookup our failure cache for intro point that might be unusable. */
  887. validate_intro_point_failure(parsed, service_id);
  888. /* It's now possible that our intro point list is empty, which means that
  889. * this descriptor is useless to us because intro points have all failed
  890. * somehow before. Discard the descriptor. */
  891. if (smartlist_len(parsed->intro_nodes) == 0) {
  892. log_info(LD_REND, "Service descriptor with service ID %s has no "
  893. "usable intro points. Discarding it.",
  894. safe_str_client(service_id));
  895. goto err;
  896. }
  897. /* Now either purge the current one and replace its content or create a
  898. * new one and add it to the rend cache. */
  899. if (!e) {
  900. e = tor_malloc_zero(sizeof(rend_cache_entry_t));
  901. strmap_set_lc(rend_cache, key, e);
  902. } else {
  903. rend_cache_decrement_allocation(rend_cache_entry_allocation(e));
  904. rend_cache_failure_remove(e->parsed);
  905. rend_service_descriptor_free(e->parsed);
  906. tor_free(e->desc);
  907. }
  908. e->parsed = parsed;
  909. e->desc = tor_malloc_zero(encoded_size + 1);
  910. strlcpy(e->desc, desc, encoded_size + 1);
  911. e->len = encoded_size;
  912. rend_cache_increment_allocation(rend_cache_entry_allocation(e));
  913. log_debug(LD_REND,"Successfully stored rend desc '%s', len %d.",
  914. safe_str_client(service_id), (int)encoded_size);
  915. if (entry) {
  916. *entry = e;
  917. }
  918. return 0;
  919. okay:
  920. if (entry) {
  921. *entry = e;
  922. }
  923. retval = 0;
  924. err:
  925. rend_service_descriptor_free(parsed);
  926. tor_free(intro_content);
  927. return retval;
  928. }