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Diffstat (limited to 'src/feature/hs/hs_cache.c')
| -rw-r--r-- | src/feature/hs/hs_cache.c | 979 |
1 files changed, 979 insertions, 0 deletions
diff --git a/src/feature/hs/hs_cache.c b/src/feature/hs/hs_cache.c new file mode 100644 index 0000000000..3772e0c0ed --- /dev/null +++ b/src/feature/hs/hs_cache.c @@ -0,0 +1,979 @@ +/* Copyright (c) 2016-2018, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file hs_cache.c + * \brief Handle hidden service descriptor caches. + **/ + +/* For unit tests.*/ +#define HS_CACHE_PRIVATE + +#include "or/or.h" +#include "or/config.h" +#include "lib/crypt_ops/crypto_format.h" +#include "lib/crypt_ops/crypto_util.h" +#include "or/hs_ident.h" +#include "or/hs_common.h" +#include "or/hs_client.h" +#include "or/hs_descriptor.h" +#include "or/networkstatus.h" +#include "or/rendcache.h" + +#include "or/hs_cache.h" + +#include "or/networkstatus_st.h" + +static int cached_client_descriptor_has_expired(time_t now, + const hs_cache_client_descriptor_t *cached_desc); + +/********************** Directory HS cache ******************/ + +/* Directory descriptor cache. Map indexed by blinded key. */ +static digest256map_t *hs_cache_v3_dir; + +/* Remove a given descriptor from our cache. */ +static void +remove_v3_desc_as_dir(const hs_cache_dir_descriptor_t *desc) +{ + tor_assert(desc); + digest256map_remove(hs_cache_v3_dir, desc->key); +} + +/* Store a given descriptor in our cache. */ +static void +store_v3_desc_as_dir(hs_cache_dir_descriptor_t *desc) +{ + tor_assert(desc); + digest256map_set(hs_cache_v3_dir, desc->key, desc); +} + +/* Query our cache and return the entry or NULL if not found. */ +static hs_cache_dir_descriptor_t * +lookup_v3_desc_as_dir(const uint8_t *key) +{ + tor_assert(key); + return digest256map_get(hs_cache_v3_dir, key); +} + +#define cache_dir_desc_free(val) \ + FREE_AND_NULL(hs_cache_dir_descriptor_t, cache_dir_desc_free_, (val)) + +/* Free a directory descriptor object. */ +static void +cache_dir_desc_free_(hs_cache_dir_descriptor_t *desc) +{ + if (desc == NULL) { + return; + } + hs_desc_plaintext_data_free(desc->plaintext_data); + tor_free(desc->encoded_desc); + tor_free(desc); +} + +/* Helper function: Use by the free all function using the digest256map + * interface to cache entries. */ +static void +cache_dir_desc_free_void(void *ptr) +{ + cache_dir_desc_free_(ptr); +} + +/* Create a new directory cache descriptor object from a encoded descriptor. + * On success, return the heap-allocated cache object, otherwise return NULL if + * we can't decode the descriptor. */ +static hs_cache_dir_descriptor_t * +cache_dir_desc_new(const char *desc) +{ + hs_cache_dir_descriptor_t *dir_desc; + + tor_assert(desc); + + dir_desc = tor_malloc_zero(sizeof(hs_cache_dir_descriptor_t)); + dir_desc->plaintext_data = + tor_malloc_zero(sizeof(hs_desc_plaintext_data_t)); + dir_desc->encoded_desc = tor_strdup(desc); + + if (hs_desc_decode_plaintext(desc, dir_desc->plaintext_data) < 0) { + log_debug(LD_DIR, "Unable to decode descriptor. Rejecting."); + goto err; + } + + /* The blinded pubkey is the indexed key. */ + dir_desc->key = dir_desc->plaintext_data->blinded_pubkey.pubkey; + dir_desc->created_ts = time(NULL); + return dir_desc; + + err: + cache_dir_desc_free(dir_desc); + return NULL; +} + +/* Return the size of a cache entry in bytes. */ +static size_t +cache_get_dir_entry_size(const hs_cache_dir_descriptor_t *entry) +{ + return (sizeof(*entry) + hs_desc_plaintext_obj_size(entry->plaintext_data) + + strlen(entry->encoded_desc)); +} + +/* Try to store a valid version 3 descriptor in the directory cache. Return 0 + * on success else a negative value is returned indicating that we have a + * newer version in our cache. On error, caller is responsible to free the + * given descriptor desc. */ +static int +cache_store_v3_as_dir(hs_cache_dir_descriptor_t *desc) +{ + hs_cache_dir_descriptor_t *cache_entry; + + tor_assert(desc); + + /* Verify if we have an entry in the cache for that key and if yes, check + * if we should replace it? */ + cache_entry = lookup_v3_desc_as_dir(desc->key); + if (cache_entry != NULL) { + /* Only replace descriptor if revision-counter is greater than the one + * in our cache */ + if (cache_entry->plaintext_data->revision_counter >= + desc->plaintext_data->revision_counter) { + log_info(LD_REND, "Descriptor revision counter in our cache is " + "greater or equal than the one we received (%d/%d). " + "Rejecting!", + (int)cache_entry->plaintext_data->revision_counter, + (int)desc->plaintext_data->revision_counter); + goto err; + } + /* We now know that the descriptor we just received is a new one so + * remove the entry we currently have from our cache so we can then + * store the new one. */ + remove_v3_desc_as_dir(cache_entry); + rend_cache_decrement_allocation(cache_get_dir_entry_size(cache_entry)); + cache_dir_desc_free(cache_entry); + } + /* Store the descriptor we just got. We are sure here that either we + * don't have the entry or we have a newer descriptor and the old one + * has been removed from the cache. */ + store_v3_desc_as_dir(desc); + + /* Update our total cache size with this entry for the OOM. This uses the + * old HS protocol cache subsystem for which we are tied with. */ + rend_cache_increment_allocation(cache_get_dir_entry_size(desc)); + + /* XXX: Update HS statistics. We should have specific stats for v3. */ + + return 0; + + err: + return -1; +} + +/* Using the query which is the base64 encoded blinded key of a version 3 + * descriptor, lookup in our directory cache the entry. If found, 1 is + * returned and desc_out is populated with a newly allocated string being the + * encoded descriptor. If not found, 0 is returned and desc_out is untouched. + * On error, a negative value is returned and desc_out is untouched. */ +static int +cache_lookup_v3_as_dir(const char *query, const char **desc_out) +{ + int found = 0; + ed25519_public_key_t blinded_key; + const hs_cache_dir_descriptor_t *entry; + + tor_assert(query); + + /* Decode blinded key using the given query value. */ + if (ed25519_public_from_base64(&blinded_key, query) < 0) { + log_info(LD_REND, "Unable to decode the v3 HSDir query %s.", + safe_str_client(query)); + goto err; + } + + entry = lookup_v3_desc_as_dir(blinded_key.pubkey); + if (entry != NULL) { + found = 1; + if (desc_out) { + *desc_out = entry->encoded_desc; + } + } + + return found; + + err: + return -1; +} + +/* Clean the v3 cache by removing any entry that has expired using the + * <b>global_cutoff</b> value. If <b>global_cutoff</b> is 0, the cleaning + * process will use the lifetime found in the plaintext data section. Return + * the number of bytes cleaned. */ +STATIC size_t +cache_clean_v3_as_dir(time_t now, time_t global_cutoff) +{ + size_t bytes_removed = 0; + + /* Code flow error if this ever happens. */ + tor_assert(global_cutoff >= 0); + + if (!hs_cache_v3_dir) { /* No cache to clean. Just return. */ + return 0; + } + + DIGEST256MAP_FOREACH_MODIFY(hs_cache_v3_dir, key, + hs_cache_dir_descriptor_t *, entry) { + size_t entry_size; + time_t cutoff = global_cutoff; + if (!cutoff) { + /* Cutoff is the lifetime of the entry found in the descriptor. */ + cutoff = now - entry->plaintext_data->lifetime_sec; + } + + /* If the entry has been created _after_ the cutoff, not expired so + * continue to the next entry in our v3 cache. */ + if (entry->created_ts > cutoff) { + continue; + } + /* Here, our entry has expired, remove and free. */ + MAP_DEL_CURRENT(key); + entry_size = cache_get_dir_entry_size(entry); + bytes_removed += entry_size; + /* Entry is not in the cache anymore, destroy it. */ + cache_dir_desc_free(entry); + /* Update our cache entry allocation size for the OOM. */ + rend_cache_decrement_allocation(entry_size); + /* Logging. */ + { + char key_b64[BASE64_DIGEST256_LEN + 1]; + digest256_to_base64(key_b64, (const char *) key); + log_info(LD_REND, "Removing v3 descriptor '%s' from HSDir cache", + safe_str_client(key_b64)); + } + } DIGEST256MAP_FOREACH_END; + + return bytes_removed; +} + +/* Given an encoded descriptor, store it in the directory cache depending on + * which version it is. Return a negative value on error. On success, 0 is + * returned. */ +int +hs_cache_store_as_dir(const char *desc) +{ + hs_cache_dir_descriptor_t *dir_desc = NULL; + + tor_assert(desc); + + /* Create a new cache object. This can fail if the descriptor plaintext data + * is unparseable which in this case a log message will be triggered. */ + dir_desc = cache_dir_desc_new(desc); + if (dir_desc == NULL) { + goto err; + } + + /* Call the right function against the descriptor version. At this point, + * we are sure that the descriptor's version is supported else the + * decoding would have failed. */ + switch (dir_desc->plaintext_data->version) { + case HS_VERSION_THREE: + default: + if (cache_store_v3_as_dir(dir_desc) < 0) { + goto err; + } + break; + } + return 0; + + err: + cache_dir_desc_free(dir_desc); + return -1; +} + +/* Using the query, lookup in our directory cache the entry. If found, 1 is + * returned and desc_out is populated with a newly allocated string being + * the encoded descriptor. If not found, 0 is returned and desc_out is + * untouched. On error, a negative value is returned and desc_out is + * untouched. */ +int +hs_cache_lookup_as_dir(uint32_t version, const char *query, + const char **desc_out) +{ + int found; + + tor_assert(query); + /* This should never be called with an unsupported version. */ + tor_assert(hs_desc_is_supported_version(version)); + + switch (version) { + case HS_VERSION_THREE: + default: + found = cache_lookup_v3_as_dir(query, desc_out); + break; + } + + return found; +} + +/* Clean all directory caches using the current time now. */ +void +hs_cache_clean_as_dir(time_t now) +{ + time_t cutoff; + + /* Start with v2 cache cleaning. */ + cutoff = now - rend_cache_max_entry_lifetime(); + rend_cache_clean_v2_descs_as_dir(cutoff); + + /* Now, clean the v3 cache. Set the cutoff to 0 telling the cleanup function + * to compute the cutoff by itself using the lifetime value. */ + cache_clean_v3_as_dir(now, 0); +} + +/********************** Client-side HS cache ******************/ + +/* Client-side HS descriptor cache. Map indexed by service identity key. */ +static digest256map_t *hs_cache_v3_client; + +/* Client-side introduction point state cache. Map indexed by service public + * identity key (onion address). It contains hs_cache_client_intro_state_t + * objects all related to a specific service. */ +static digest256map_t *hs_cache_client_intro_state; + +/* Return the size of a client cache entry in bytes. */ +static size_t +cache_get_client_entry_size(const hs_cache_client_descriptor_t *entry) +{ + return sizeof(*entry) + + strlen(entry->encoded_desc) + hs_desc_obj_size(entry->desc); +} + +/* Remove a given descriptor from our cache. */ +static void +remove_v3_desc_as_client(const hs_cache_client_descriptor_t *desc) +{ + tor_assert(desc); + digest256map_remove(hs_cache_v3_client, desc->key.pubkey); + /* Update cache size with this entry for the OOM handler. */ + rend_cache_decrement_allocation(cache_get_client_entry_size(desc)); +} + +/* Store a given descriptor in our cache. */ +static void +store_v3_desc_as_client(hs_cache_client_descriptor_t *desc) +{ + tor_assert(desc); + digest256map_set(hs_cache_v3_client, desc->key.pubkey, desc); + /* Update cache size with this entry for the OOM handler. */ + rend_cache_increment_allocation(cache_get_client_entry_size(desc)); +} + +/* Query our cache and return the entry or NULL if not found or if expired. */ +STATIC hs_cache_client_descriptor_t * +lookup_v3_desc_as_client(const uint8_t *key) +{ + time_t now = approx_time(); + hs_cache_client_descriptor_t *cached_desc; + + tor_assert(key); + + /* Do the lookup */ + cached_desc = digest256map_get(hs_cache_v3_client, key); + if (!cached_desc) { + return NULL; + } + + /* Don't return expired entries */ + if (cached_client_descriptor_has_expired(now, cached_desc)) { + return NULL; + } + + return cached_desc; +} + +/* Parse the encoded descriptor in <b>desc_str</b> using + * <b>service_identity_pk<b> to decrypt it first. + * + * If everything goes well, allocate and return a new + * hs_cache_client_descriptor_t object. In case of error, return NULL. */ +static hs_cache_client_descriptor_t * +cache_client_desc_new(const char *desc_str, + const ed25519_public_key_t *service_identity_pk) +{ + hs_descriptor_t *desc = NULL; + hs_cache_client_descriptor_t *client_desc = NULL; + + tor_assert(desc_str); + tor_assert(service_identity_pk); + + /* Decode the descriptor we just fetched. */ + if (hs_client_decode_descriptor(desc_str, service_identity_pk, &desc) < 0) { + goto end; + } + tor_assert(desc); + + /* All is good: make a cache object for this descriptor */ + client_desc = tor_malloc_zero(sizeof(hs_cache_client_descriptor_t)); + ed25519_pubkey_copy(&client_desc->key, service_identity_pk); + /* Set expiration time for this cached descriptor to be the start of the next + * time period since that's when clients need to start using the next blinded + * pk of the service (and hence will need its next descriptor). */ + client_desc->expiration_ts = hs_get_start_time_of_next_time_period(0); + client_desc->desc = desc; + client_desc->encoded_desc = tor_strdup(desc_str); + + end: + return client_desc; +} + +#define cache_client_desc_free(val) \ + FREE_AND_NULL(hs_cache_client_descriptor_t, cache_client_desc_free_, (val)) + +/** Free memory allocated by <b>desc</b>. */ +static void +cache_client_desc_free_(hs_cache_client_descriptor_t *desc) +{ + if (desc == NULL) { + return; + } + hs_descriptor_free(desc->desc); + memwipe(&desc->key, 0, sizeof(desc->key)); + memwipe(desc->encoded_desc, 0, strlen(desc->encoded_desc)); + tor_free(desc->encoded_desc); + tor_free(desc); +} + +/** Helper function: Use by the free all function to clear the client cache */ +static void +cache_client_desc_free_void(void *ptr) +{ + hs_cache_client_descriptor_t *desc = ptr; + cache_client_desc_free(desc); +} + +/* Return a newly allocated and initialized hs_cache_intro_state_t object. */ +static hs_cache_intro_state_t * +cache_intro_state_new(void) +{ + hs_cache_intro_state_t *state = tor_malloc_zero(sizeof(*state)); + state->created_ts = approx_time(); + return state; +} + +#define cache_intro_state_free(val) \ + FREE_AND_NULL(hs_cache_intro_state_t, cache_intro_state_free_, (val)) + +/* Free an hs_cache_intro_state_t object. */ +static void +cache_intro_state_free_(hs_cache_intro_state_t *state) +{ + tor_free(state); +} + +/* Helper function: use by the free all function. */ +static void +cache_intro_state_free_void(void *state) +{ + cache_intro_state_free_(state); +} + +/* Return a newly allocated and initialized hs_cache_client_intro_state_t + * object. */ +static hs_cache_client_intro_state_t * +cache_client_intro_state_new(void) +{ + hs_cache_client_intro_state_t *cache = tor_malloc_zero(sizeof(*cache)); + cache->intro_points = digest256map_new(); + return cache; +} + +#define cache_client_intro_state_free(val) \ + FREE_AND_NULL(hs_cache_client_intro_state_t, \ + cache_client_intro_state_free_, (val)) + +/* Free a cache client intro state object. */ +static void +cache_client_intro_state_free_(hs_cache_client_intro_state_t *cache) +{ + if (cache == NULL) { + return; + } + digest256map_free(cache->intro_points, cache_intro_state_free_void); + tor_free(cache); +} + +/* Helper function: use by the free all function. */ +static void +cache_client_intro_state_free_void(void *entry) +{ + cache_client_intro_state_free_(entry); +} + +/* For the given service identity key service_pk and an introduction + * authentication key auth_key, lookup the intro state object. Return 1 if + * found and put it in entry if not NULL. Return 0 if not found and entry is + * untouched. */ +static int +cache_client_intro_state_lookup(const ed25519_public_key_t *service_pk, + const ed25519_public_key_t *auth_key, + hs_cache_intro_state_t **entry) +{ + hs_cache_intro_state_t *state; + hs_cache_client_intro_state_t *cache; + + tor_assert(service_pk); + tor_assert(auth_key); + + /* Lookup the intro state cache for this service key. */ + cache = digest256map_get(hs_cache_client_intro_state, service_pk->pubkey); + if (cache == NULL) { + goto not_found; + } + + /* From the cache we just found for the service, lookup in the introduction + * points map for the given authentication key. */ + state = digest256map_get(cache->intro_points, auth_key->pubkey); + if (state == NULL) { + goto not_found; + } + if (entry) { + *entry = state; + } + return 1; + not_found: + return 0; +} + +/* Note the given failure in state. */ +static void +cache_client_intro_state_note(hs_cache_intro_state_t *state, + rend_intro_point_failure_t failure) +{ + tor_assert(state); + switch (failure) { + case INTRO_POINT_FAILURE_GENERIC: + state->error = 1; + break; + case INTRO_POINT_FAILURE_TIMEOUT: + state->timed_out = 1; + break; + case INTRO_POINT_FAILURE_UNREACHABLE: + state->unreachable_count++; + break; + default: + tor_assert_nonfatal_unreached(); + return; + } +} + +/* For the given service identity key service_pk and an introduction + * authentication key auth_key, add an entry in the client intro state cache + * If no entry exists for the service, it will create one. If state is non + * NULL, it will point to the new intro state entry. */ +static void +cache_client_intro_state_add(const ed25519_public_key_t *service_pk, + const ed25519_public_key_t *auth_key, + hs_cache_intro_state_t **state) +{ + hs_cache_intro_state_t *entry, *old_entry; + hs_cache_client_intro_state_t *cache; + + tor_assert(service_pk); + tor_assert(auth_key); + + /* Lookup the state cache for this service key. */ + cache = digest256map_get(hs_cache_client_intro_state, service_pk->pubkey); + if (cache == NULL) { + cache = cache_client_intro_state_new(); + digest256map_set(hs_cache_client_intro_state, service_pk->pubkey, cache); + } + + entry = cache_intro_state_new(); + old_entry = digest256map_set(cache->intro_points, auth_key->pubkey, entry); + /* This should never happened because the code flow is to lookup the entry + * before adding it. But, just in case, non fatal assert and free it. */ + tor_assert_nonfatal(old_entry == NULL); + tor_free(old_entry); + + if (state) { + *state = entry; + } +} + +/* Remove every intro point state entry from cache that has been created + * before or at the cutoff. */ +static void +cache_client_intro_state_clean(time_t cutoff, + hs_cache_client_intro_state_t *cache) +{ + tor_assert(cache); + + DIGEST256MAP_FOREACH_MODIFY(cache->intro_points, key, + hs_cache_intro_state_t *, entry) { + if (entry->created_ts <= cutoff) { + cache_intro_state_free(entry); + MAP_DEL_CURRENT(key); + } + } DIGEST256MAP_FOREACH_END; +} + +/* Return true iff no intro points are in this cache. */ +static int +cache_client_intro_state_is_empty(const hs_cache_client_intro_state_t *cache) +{ + return digest256map_isempty(cache->intro_points); +} + +/** Check whether <b>client_desc</b> is useful for us, and store it in the + * client-side HS cache if so. The client_desc is freed if we already have a + * fresher (higher revision counter count) in the cache. */ +static int +cache_store_as_client(hs_cache_client_descriptor_t *client_desc) +{ + hs_cache_client_descriptor_t *cache_entry; + + /* TODO: Heavy code duplication with cache_store_as_dir(). Consider + * refactoring and uniting! */ + + tor_assert(client_desc); + + /* Check if we already have a descriptor from this HS in cache. If we do, + * check if this descriptor is newer than the cached one */ + cache_entry = lookup_v3_desc_as_client(client_desc->key.pubkey); + if (cache_entry != NULL) { + /* If we have an entry in our cache that has a revision counter greater + * than the one we just fetched, discard the one we fetched. */ + if (cache_entry->desc->plaintext_data.revision_counter > + client_desc->desc->plaintext_data.revision_counter) { + cache_client_desc_free(client_desc); + goto done; + } + /* Remove old entry. Make space for the new one! */ + remove_v3_desc_as_client(cache_entry); + cache_client_desc_free(cache_entry); + } + + /* Store descriptor in cache */ + store_v3_desc_as_client(client_desc); + + done: + return 0; +} + +/* Return true iff the cached client descriptor at <b>cached_desc</b has + * expired. */ +static int +cached_client_descriptor_has_expired(time_t now, + const hs_cache_client_descriptor_t *cached_desc) +{ + /* We use the current consensus time to see if we should expire this + * descriptor since we use consensus time for all other parts of the protocol + * as well (e.g. to build the blinded key and compute time periods). */ + const networkstatus_t *ns = networkstatus_get_live_consensus(now); + /* If we don't have a recent consensus, consider this entry expired since we + * will want to fetch a new HS desc when we get a live consensus. */ + if (!ns) { + return 1; + } + + if (cached_desc->expiration_ts <= ns->valid_after) { + return 1; + } + + return 0; +} + +/* clean the client cache using now as the current time. Return the total size + * of removed bytes from the cache. */ +static size_t +cache_clean_v3_as_client(time_t now) +{ + size_t bytes_removed = 0; + + if (!hs_cache_v3_client) { /* No cache to clean. Just return. */ + return 0; + } + + DIGEST256MAP_FOREACH_MODIFY(hs_cache_v3_client, key, + hs_cache_client_descriptor_t *, entry) { + size_t entry_size; + + /* If the entry has not expired, continue to the next cached entry */ + if (!cached_client_descriptor_has_expired(now, entry)) { + continue; + } + /* Here, our entry has expired, remove and free. */ + MAP_DEL_CURRENT(key); + entry_size = cache_get_client_entry_size(entry); + bytes_removed += entry_size; + /* Entry is not in the cache anymore, destroy it. */ + cache_client_desc_free(entry); + /* Update our OOM. We didn't use the remove() function because we are in + * a loop so we have to explicitly decrement. */ + rend_cache_decrement_allocation(entry_size); + /* Logging. */ + { + char key_b64[BASE64_DIGEST256_LEN + 1]; + digest256_to_base64(key_b64, (const char *) key); + log_info(LD_REND, "Removing hidden service v3 descriptor '%s' " + "from client cache", + safe_str_client(key_b64)); + } + } DIGEST256MAP_FOREACH_END; + + return bytes_removed; +} + +/** Public API: Given the HS ed25519 identity public key in <b>key</b>, return + * its HS encoded descriptor if it's stored in our cache, or NULL if not. */ +const char * +hs_cache_lookup_encoded_as_client(const ed25519_public_key_t *key) +{ + hs_cache_client_descriptor_t *cached_desc = NULL; + + tor_assert(key); + + cached_desc = lookup_v3_desc_as_client(key->pubkey); + if (cached_desc) { + tor_assert(cached_desc->encoded_desc); + return cached_desc->encoded_desc; + } + + return NULL; +} + +/** Public API: Given the HS ed25519 identity public key in <b>key</b>, return + * its HS descriptor if it's stored in our cache, or NULL if not. */ +const hs_descriptor_t * +hs_cache_lookup_as_client(const ed25519_public_key_t *key) +{ + hs_cache_client_descriptor_t *cached_desc = NULL; + + tor_assert(key); + + cached_desc = lookup_v3_desc_as_client(key->pubkey); + if (cached_desc) { + tor_assert(cached_desc->desc); + return cached_desc->desc; + } + + return NULL; +} + +/** Public API: Given an encoded descriptor, store it in the client HS + * cache. Return -1 on error, 0 on success .*/ +int +hs_cache_store_as_client(const char *desc_str, + const ed25519_public_key_t *identity_pk) +{ + hs_cache_client_descriptor_t *client_desc = NULL; + + tor_assert(desc_str); + tor_assert(identity_pk); + + /* Create client cache descriptor object */ + client_desc = cache_client_desc_new(desc_str, identity_pk); + if (!client_desc) { + log_warn(LD_GENERAL, "Failed to parse received descriptor %s.", + escaped(desc_str)); + goto err; + } + + /* Push it to the cache */ + if (cache_store_as_client(client_desc) < 0) { + goto err; + } + + return 0; + + err: + cache_client_desc_free(client_desc); + return -1; +} + +/* Clean all client caches using the current time now. */ +void +hs_cache_clean_as_client(time_t now) +{ + /* Start with v2 cache cleaning. */ + rend_cache_clean(now, REND_CACHE_TYPE_CLIENT); + /* Now, clean the v3 cache. Set the cutoff to 0 telling the cleanup function + * to compute the cutoff by itself using the lifetime value. */ + cache_clean_v3_as_client(now); +} + +/* Purge the client descriptor cache. */ +void +hs_cache_purge_as_client(void) +{ + DIGEST256MAP_FOREACH_MODIFY(hs_cache_v3_client, key, + hs_cache_client_descriptor_t *, entry) { + size_t entry_size = cache_get_client_entry_size(entry); + MAP_DEL_CURRENT(key); + cache_client_desc_free(entry); + /* Update our OOM. We didn't use the remove() function because we are in + * a loop so we have to explicitly decrement. */ + rend_cache_decrement_allocation(entry_size); + } DIGEST256MAP_FOREACH_END; + + log_info(LD_REND, "Hidden service client descriptor cache purged."); +} + +/* For a given service identity public key and an introduction authentication + * key, note the given failure in the client intro state cache. */ +void +hs_cache_client_intro_state_note(const ed25519_public_key_t *service_pk, + const ed25519_public_key_t *auth_key, + rend_intro_point_failure_t failure) +{ + int found; + hs_cache_intro_state_t *entry; + + tor_assert(service_pk); + tor_assert(auth_key); + + found = cache_client_intro_state_lookup(service_pk, auth_key, &entry); + if (!found) { + /* Create a new entry and add it to the cache. */ + cache_client_intro_state_add(service_pk, auth_key, &entry); + } + /* Note down the entry. */ + cache_client_intro_state_note(entry, failure); +} + +/* For a given service identity public key and an introduction authentication + * key, return true iff it is present in the failure cache. */ +const hs_cache_intro_state_t * +hs_cache_client_intro_state_find(const ed25519_public_key_t *service_pk, + const ed25519_public_key_t *auth_key) +{ + hs_cache_intro_state_t *state = NULL; + cache_client_intro_state_lookup(service_pk, auth_key, &state); + return state; +} + +/* Cleanup the client introduction state cache. */ +void +hs_cache_client_intro_state_clean(time_t now) +{ + time_t cutoff = now - HS_CACHE_CLIENT_INTRO_STATE_MAX_AGE; + + DIGEST256MAP_FOREACH_MODIFY(hs_cache_client_intro_state, key, + hs_cache_client_intro_state_t *, cache) { + /* Cleanup intro points failure. */ + cache_client_intro_state_clean(cutoff, cache); + + /* Is this cache empty for this service key? If yes, remove it from the + * cache. Else keep it. */ + if (cache_client_intro_state_is_empty(cache)) { + cache_client_intro_state_free(cache); + MAP_DEL_CURRENT(key); + } + } DIGEST256MAP_FOREACH_END; +} + +/* Purge the client introduction state cache. */ +void +hs_cache_client_intro_state_purge(void) +{ + DIGEST256MAP_FOREACH_MODIFY(hs_cache_client_intro_state, key, + hs_cache_client_intro_state_t *, cache) { + MAP_DEL_CURRENT(key); + cache_client_intro_state_free(cache); + } DIGEST256MAP_FOREACH_END; + + log_info(LD_REND, "Hidden service client introduction point state " + "cache purged."); +} + +/**************** Generics *********************************/ + +/* Do a round of OOM cleanup on all directory caches. Return the amount of + * removed bytes. It is possible that the returned value is lower than + * min_remove_bytes if the caches get emptied out so the caller should be + * aware of this. */ +size_t +hs_cache_handle_oom(time_t now, size_t min_remove_bytes) +{ + time_t k; + size_t bytes_removed = 0; + + /* Our OOM handler called with 0 bytes to remove is a code flow error. */ + tor_assert(min_remove_bytes != 0); + + /* The algorithm is as follow. K is the oldest expected descriptor age. + * + * 1) Deallocate all entries from v2 cache that are older than K hours. + * 1.1) If the amount of remove bytes has been reached, stop. + * 2) Deallocate all entries from v3 cache that are older than K hours + * 2.1) If the amount of remove bytes has been reached, stop. + * 3) Set K = K - RendPostPeriod and repeat process until K is < 0. + * + * This ends up being O(Kn). + */ + + /* Set K to the oldest expected age in seconds which is the maximum + * lifetime of a cache entry. We'll use the v2 lifetime because it's much + * bigger than the v3 thus leading to cleaning older descriptors. */ + k = rend_cache_max_entry_lifetime(); + + do { + time_t cutoff; + + /* If K becomes negative, it means we've empty the caches so stop and + * return what we were able to cleanup. */ + if (k < 0) { + break; + } + /* Compute a cutoff value with K and the current time. */ + cutoff = now - k; + + /* Start by cleaning the v2 cache with that cutoff. */ + bytes_removed += rend_cache_clean_v2_descs_as_dir(cutoff); + + if (bytes_removed < min_remove_bytes) { + /* We haven't remove enough bytes so clean v3 cache. */ + bytes_removed += cache_clean_v3_as_dir(now, cutoff); + /* Decrement K by a post period to shorten the cutoff. */ + k -= get_options()->RendPostPeriod; + } + } while (bytes_removed < min_remove_bytes); + + return bytes_removed; +} + +/* Return the maximum size of a v3 HS descriptor. */ +unsigned int +hs_cache_get_max_descriptor_size(void) +{ + return (unsigned) networkstatus_get_param(NULL, + "HSV3MaxDescriptorSize", + HS_DESC_MAX_LEN, 1, INT32_MAX); +} + +/* Initialize the hidden service cache subsystem. */ +void +hs_cache_init(void) +{ + /* Calling this twice is very wrong code flow. */ + tor_assert(!hs_cache_v3_dir); + hs_cache_v3_dir = digest256map_new(); + + tor_assert(!hs_cache_v3_client); + hs_cache_v3_client = digest256map_new(); + + tor_assert(!hs_cache_client_intro_state); + hs_cache_client_intro_state = digest256map_new(); +} + +/* Cleanup the hidden service cache subsystem. */ +void +hs_cache_free_all(void) +{ + digest256map_free(hs_cache_v3_dir, cache_dir_desc_free_void); + hs_cache_v3_dir = NULL; + + digest256map_free(hs_cache_v3_client, cache_client_desc_free_void); + hs_cache_v3_client = NULL; + + digest256map_free(hs_cache_client_intro_state, + cache_client_intro_state_free_void); + hs_cache_client_intro_state = NULL; +} |