diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/or/hs_cache.c | 63 | ||||
| -rw-r--r-- | src/or/hs_cache.h | 6 |
2 files changed, 56 insertions, 13 deletions
diff --git a/src/or/hs_cache.c b/src/or/hs_cache.c index 7f2a9cbbb7..3ebe13fb4d 100644 --- a/src/or/hs_cache.c +++ b/src/or/hs_cache.c @@ -20,6 +20,9 @@ #include "hs_cache.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. */ @@ -356,12 +359,27 @@ store_v3_desc_as_client(hs_cache_client_descriptor_t *desc) rend_cache_increment_allocation(cache_get_client_entry_size(desc)); } -/* Query our cache and return the entry or NULL if not found. */ +/* 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); - return digest256map_get(hs_cache_v3_client, 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 @@ -388,7 +406,10 @@ cache_client_desc_new(const char *desc_str, /* 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); - client_desc->created_ts = approx_time(); + /* 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); @@ -603,9 +624,8 @@ cache_store_as_client(hs_cache_client_descriptor_t *client_desc) 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) { - log_info(LD_REND, "We already have fresher descriptor. Ignoring."); + if (BUG(cache_entry->desc->plaintext_data.revision_counter > + client_desc->desc->plaintext_data.revision_counter)) { cache_client_desc_free(client_desc); goto done; } @@ -621,7 +641,30 @@ cache_store_as_client(hs_cache_client_descriptor_t *client_desc) return 0; } -/* Clean the client cache using now as the current time. Return the total size +/* 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) @@ -635,11 +678,9 @@ cache_clean_v3_as_client(time_t now) DIGEST256MAP_FOREACH_MODIFY(hs_cache_v3_client, key, hs_cache_client_descriptor_t *, entry) { size_t entry_size; - time_t cutoff = now - rend_cache_max_entry_lifetime(); - /* 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) { + /* 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. */ diff --git a/src/or/hs_cache.h b/src/or/hs_cache.h index 8dbc842b95..a6beaebc10 100644 --- a/src/or/hs_cache.h +++ b/src/or/hs_cache.h @@ -103,8 +103,10 @@ typedef struct hs_cache_client_descriptor_t { /* This object is indexed using the service identity public key */ ed25519_public_key_t key; - /* When was this entry created. Used to expire entries. */ - time_t created_ts; + /* When will this entry expire? We expire cached client descriptors in the + * start of the next time period, since that's when clients need to start + * using the next blinded key of the service. */ + time_t expiration_ts; /* The cached descriptor, this object is the owner. It can't be NULL. A * cache object without a valid descriptor is not possible. */ |