February 2018 - tor-commits - lists.torproject.org

[tor/release-0.2.9] test: DoS test to make sure we exclude known relays
by nickm＠torproject.org 16 Feb '18

16 Feb '18

commit 1a4fc9cddf27595db6f5da981a557f768fa32f66 Author: David Goulet <dgoulet(a)torproject.org> Date: Fri Feb 9 11:31:01 2018 -0500 test: DoS test to make sure we exclude known relays Part of #25193 Signed-off-by: David Goulet <dgoulet(a)torproject.org> --- src/test/test_dos.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) diff --git a/src/test/test_dos.c b/src/test/test_dos.c index 6db98b9ed..cb9d9e559 100644 --- a/src/test/test_dos.c +++ b/src/test/test_dos.c @@ -10,9 +10,36 @@ #include "circuitlist.h" #include "geoip.h" #include "channel.h" +#include "microdesc.h" +#include "networkstatus.h" +#include "nodelist.h" +#include "routerlist.h" #include "test.h" #include "log_test_helpers.h" +static networkstatus_t *dummy_ns = NULL; +static networkstatus_t * +mock_networkstatus_get_latest_consensus(void) +{ + return dummy_ns; +} + +static networkstatus_t * +mock_networkstatus_get_latest_consensus_by_flavor(consensus_flavor_t f) +{ + tor_assert(f == FLAV_MICRODESC); + return dummy_ns; +} + +/* Number of address a single node_t can have. Default to the production + * value. This is to control the size of the bloom filter. */ +static int addr_per_node = 2; +static int +mock_get_estimated_address_per_node(void) +{ + return addr_per_node; +} + static unsigned int mock_enable_dos_protection(const networkstatus_t *ns) { @@ -385,10 +412,86 @@ test_dos_bucket_refill(void *arg) dos_free_all(); } +/* Test if we avoid counting a known relay. */ +static void +test_known_relay(void *arg) +{ + clientmap_entry_t *entry = NULL; + routerstatus_t *rs = NULL; microdesc_t *md = NULL; routerinfo_t *ri = NULL; + + (void) arg; + + MOCK(networkstatus_get_latest_consensus, + mock_networkstatus_get_latest_consensus); + MOCK(networkstatus_get_latest_consensus_by_flavor, + mock_networkstatus_get_latest_consensus_by_flavor); + MOCK(get_estimated_address_per_node, + mock_get_estimated_address_per_node); + MOCK(get_param_cc_enabled, mock_enable_dos_protection); + + dos_init(); + + dummy_ns = tor_malloc_zero(sizeof(*dummy_ns)); + dummy_ns->flavor = FLAV_MICRODESC; + dummy_ns->routerstatus_list = smartlist_new(); + + /* Setup an OR conn so we can pass it to the DoS subsystem. */ + or_connection_t or_conn; + tor_addr_parse(&or_conn.real_addr, "42.42.42.42"); + + rs = tor_malloc_zero(sizeof(*rs)); + rs->addr = tor_addr_to_ipv4h(&or_conn.real_addr); + crypto_rand(rs->identity_digest, sizeof(rs->identity_digest)); + smartlist_add(dummy_ns->routerstatus_list, rs); + + /* This will make the nodelist bloom filter very large + * (the_nodelist->node_addrs) so we will fail the contain test rarely. */ + addr_per_node = 1024; + nodelist_set_consensus(dummy_ns); + + /* We have now a node in our list so we'll make sure we don't count it as a + * client connection. */ + geoip_note_client_seen(GEOIP_CLIENT_CONNECT, &or_conn.real_addr, NULL, 0); + /* Suppose we have 5 connections in rapid succession, the counter should + * always be 0 because we should ignore this. */ + dos_new_client_conn(&or_conn); + dos_new_client_conn(&or_conn); + dos_new_client_conn(&or_conn); + dos_new_client_conn(&or_conn); + dos_new_client_conn(&or_conn); + entry = geoip_lookup_client(&or_conn.real_addr, NULL, GEOIP_CLIENT_CONNECT); + tt_assert(entry); + /* We should have a count of 0. */ + tt_uint_op(entry->dos_stats.concurrent_count, OP_EQ, 0); + + /* To make sure that his is working properly, make a unknown client + * connection and see if we do get it. */ + tor_addr_parse(&or_conn.real_addr, "42.42.42.43"); + geoip_note_client_seen(GEOIP_CLIENT_CONNECT, &or_conn.real_addr, NULL, 0); + dos_new_client_conn(&or_conn); + dos_new_client_conn(&or_conn); + entry = geoip_lookup_client(&or_conn.real_addr, NULL, GEOIP_CLIENT_CONNECT); + tt_assert(entry); + /* We should have a count of 2. */ + tt_uint_op(entry->dos_stats.concurrent_count, OP_EQ, 2); + + done: + routerstatus_free(rs); routerinfo_free(ri); microdesc_free(md); + smartlist_clear(dummy_ns->routerstatus_list); + networkstatus_vote_free(dummy_ns); + dos_free_all(); + UNMOCK(networkstatus_get_latest_consensus); + UNMOCK(networkstatus_get_latest_consensus_by_flavor); + UNMOCK(get_estimated_address_per_node); + UNMOCK(get_param_cc_enabled); +} + struct testcase_t dos_tests[] = { { "conn_creation", test_dos_conn_creation, TT_FORK, NULL, NULL }, { "circuit_creation", test_dos_circuit_creation, TT_FORK, NULL, NULL }, { "bucket_refill", test_dos_bucket_refill, TT_FORK, NULL, NULL }, + { "known_relay" , test_known_relay, TT_FORK, + NULL, NULL }, END_OF_TESTCASES };

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[tor/maint-0.3.2] dos: Add changes file for ticket 24902
by nickm＠torproject.org 16 Feb '18

16 Feb '18

commit 9aca7d47306222f2870ec16a7291a8215d6c3316 Author: David Goulet <dgoulet(a)torproject.org> Date: Tue Jan 30 09:15:33 2018 -0500 dos: Add changes file for ticket 24902 Signed-off-by: David Goulet <dgoulet(a)torproject.org> --- changes/ticket24902 | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/changes/ticket24902 b/changes/ticket24902 new file mode 100644 index 000000000..1a2ef95cc --- /dev/null +++ b/changes/ticket24902 @@ -0,0 +1,13 @@ + o Major features (denial of service mitigation): + - Give relays some defenses against the recent network overload. We start + with three defenses (default parameters in parentheses). First: if a + single client address makes too many concurrent connections (>100), hang + up on further connections. Second: if a single client address makes + circuits too quickly (more than 3 per second, with an allowed burst of + 90) while also having too many connections open (3), refuse new create + cells for the next while (1-2 hours). Third: if a client asks to + establish a rendezvous point to you directly, ignore the request. These + defenses can be manually controlled by new torrc options, but relays + will also take guidance from consensus parameters, so there's no need to + configure anything manually. Implements ticket 24902. +

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[tor/maint-0.3.2] Merge branch 'ticket25122_029_02' into ticket24902_029_05
by nickm＠torproject.org 16 Feb '18

16 Feb '18

commit 475218c108ad84aa302f0daec013faab9ff778f2 Merge: 33d9889a2 e758d659a Author: David Goulet <dgoulet(a)torproject.org> Date: Fri Feb 2 14:55:01 2018 -0500 Merge branch 'ticket25122_029_02' into ticket24902_029_05 changes/ticket25122 | 4 ++ src/or/geoip.c | 148 ++++++++++++++++++++++++++++++++++++++++++++++++++-- src/or/geoip.h | 2 + src/or/relay.c | 16 ++++-- src/test/test.c | 18 +++++++ 5 files changed, 180 insertions(+), 8 deletions(-) diff --cc src/or/geoip.c index 4e4f6e639,76fca43f6..20dad5f15 --- a/src/or/geoip.c +++ b/src/or/geoip.c @@@ -516,9 -574,7 +557,10 @@@ clientmap_entry_free(clientmap_entry_t if (!ent) return; + /* This entry is about to be freed so pass it to the DoS subsystem to see if + * any actions can be taken about it. */ + dos_geoip_entry_about_to_free(ent); + geoip_decrement_client_history_cache_size(clientmap_entry_size(ent)); tor_free(ent->transport_name); tor_free(ent); @@@ -573,13 -651,13 +640,9 @@@ geoip_note_client_seen(geoip_client_act safe_str_client(fmt_addr((addr))), transport_name ? transport_name : "<no transport>"); - tor_addr_copy(&lookup.addr, addr); - lookup.action = (int)action; - lookup.transport_name = (char*) transport_name; - ent = HT_FIND(clientmap, &client_history, &lookup); - + ent = geoip_lookup_client(addr, transport_name, action); if (! ent) { - ent = tor_malloc_zero(sizeof(clientmap_entry_t)); - tor_addr_copy(&ent->addr, addr); - if (transport_name) - ent->transport_name = tor_strdup(transport_name); - ent->action = (int)action; + ent = clientmap_entry_new(action, addr, transport_name); HT_INSERT(clientmap, &client_history, ent); } if (now / 60 <= (int)MAX_LAST_SEEN_IN_MINUTES && now >= 0) @@@ -621,25 -699,81 +684,100 @@@ geoip_remove_old_clients(time_t cutoff &cutoff); } +/* Return a client entry object matching the given address, transport name and + * geoip action from the clientmap. NULL if not found. The transport_name can + * be NULL. */ +clientmap_entry_t * +geoip_lookup_client(const tor_addr_t *addr, const char *transport_name, + geoip_client_action_t action) +{ + clientmap_entry_t lookup; + + tor_assert(addr); + + /* We always look for a client connection with no transport. */ + tor_addr_copy(&lookup.addr, addr); + lookup.action = action; + lookup.transport_name = (char *) transport_name; + + return HT_FIND(clientmap, &client_history, &lookup); +} + + /* Cleanup client entries older than the cutoff. Used for the OOM. Return the + * number of bytes freed. If 0 is returned, nothing was freed. */ + static size_t + oom_clean_client_entries(time_t cutoff) + { + size_t bytes = 0; + clientmap_entry_t **ent, **ent_next; + + for (ent = HT_START(clientmap, &client_history); ent; ent = ent_next) { + clientmap_entry_t *entry = *ent; + if (entry->last_seen_in_minutes < (cutoff / 60)) { + ent_next = HT_NEXT_RMV(clientmap, &client_history, ent); + bytes += clientmap_entry_size(entry); + clientmap_entry_free(entry); + } else { + ent_next = HT_NEXT(clientmap, &client_history, ent); + } + } + return bytes; + } + + /* Below this minimum lifetime, the OOM won't cleanup any entries. */ + #define GEOIP_CLIENT_CACHE_OOM_MIN_CUTOFF (4 * 60 * 60) + /* The OOM moves the cutoff by that much every run. */ + #define GEOIP_CLIENT_CACHE_OOM_STEP (15 * 50) + + /* Cleanup the geoip client history cache called from the OOM handler. Return + * the amount of bytes removed. This can return a value below or above + * min_remove_bytes but will stop as oon as the min_remove_bytes has been + * reached. */ + size_t + geoip_client_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); + + /* Set k to the initial cutoff of an entry. We then going to move it by step + * to try to remove as much as we can. */ + k = WRITE_STATS_INTERVAL; + + do { + time_t cutoff; + + /* If k has reached the minimum lifetime, we have to stop else we might + * remove every single entries which would be pretty bad for the DoS + * mitigation subsystem if by just filling the geoip cache, it was enough + * to trigger the OOM and clean every single entries. */ + if (k <= GEOIP_CLIENT_CACHE_OOM_MIN_CUTOFF) { + break; + } + + cutoff = now - k; + bytes_removed += oom_clean_client_entries(cutoff); + k -= GEOIP_CLIENT_CACHE_OOM_STEP; + } while (bytes_removed < min_remove_bytes); + + return bytes_removed; + } + + /* Return the total size in bytes of the client history cache. */ + size_t + geoip_client_cache_total_allocation(void) + { + size_t bytes = 0; + clientmap_entry_t **ent; + + HT_FOREACH(ent, clientmap, &client_history) { + bytes += clientmap_entry_size(*ent); + } + return bytes; + } + /** How many responses are we giving to clients requesting v3 network * statuses? */ static uint32_t ns_v3_responses[GEOIP_NS_RESPONSE_NUM]; diff --cc src/or/geoip.h index aa0fca50f,42d0c1cfd..c8ea9f85e --- a/src/or/geoip.h +++ b/src/or/geoip.h @@@ -57,9 -33,8 +57,11 @@@ void geoip_note_client_seen(geoip_clien const tor_addr_t *addr, const char *transport_name, time_t now); void geoip_remove_old_clients(time_t cutoff); +clientmap_entry_t *geoip_lookup_client(const tor_addr_t *addr, + const char *transport_name, + geoip_client_action_t action); + size_t geoip_client_cache_total_allocation(void); + size_t geoip_client_cache_handle_oom(time_t now, size_t min_remove_bytes); void geoip_note_ns_response(geoip_ns_response_t response); char *geoip_get_transport_history(void);

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[tor/maint-0.3.2] dos: Clear connection tracked flag if geoip entry is removed
by nickm＠torproject.org 16 Feb '18

16 Feb '18

commit 82de4ea900c5d3513214b127421890595343bfaa Author: David Goulet <dgoulet(a)torproject.org> Date: Thu Jan 25 09:44:21 2018 -0500 dos: Clear connection tracked flag if geoip entry is removed Imagine this scenario. We had 10 connections over the 24h lifetime of a geoip cache entry. The lifetime of the entry has been reached so it is about to get freed but 2 connections remain for it. After the free, a third connection comes in thus making us create a new geoip entry for that address matching the 2 previous ones that are still alive. If they end up being closed, we'll have a concurrent count desynch from what the reality is. To mitigate this probably very rare scenario in practice, when we free a geoip entry and it has a concurrent count above 0, we'll go over all connections matching the address and clear out the tracked flag. So once they are closed, we don't try to decrement the count. Signed-off-by: David Goulet <dgoulet(a)torproject.org> --- src/or/dos.c | 35 +++++++++++++++++++++++++++++++++++ src/or/dos.h | 4 ++++ src/or/geoip.c | 4 ++++ 3 files changed, 43 insertions(+) diff --git a/src/or/dos.c b/src/or/dos.c index 40e88aead..5af75ca57 100644 --- a/src/or/dos.c +++ b/src/or/dos.c @@ -528,6 +528,41 @@ dos_conn_addr_get_defense_type(const tor_addr_t *addr) /* General API */ +/* Take any appropriate actions for the given geoip entry that is about to get + * freed. This is called for every entry that is being freed. + * + * This function will clear out the connection tracked flag if the concurrent + * count of the entry is above 0 so if those connections end up being seen by + * this subsystem, we won't try to decrement the counter for a new geoip entry + * that might have been added after this call for the same address. */ +void +dos_geoip_entry_about_to_free(const clientmap_entry_t *geoip_ent) +{ + tor_assert(geoip_ent); + + /* The count is down to 0 meaning no connections right now, we can safely + * clear the geoip entry from the cache. */ + if (geoip_ent->dos_stats.concurrent_count == 0) { + goto end; + } + + /* For each connection matching the geoip entry address, we'll clear the + * tracked flag because the entry is about to get removed from the geoip + * cache. We do not try to decrement if the flag is not set. */ + SMARTLIST_FOREACH_BEGIN(get_connection_array(), connection_t *, conn) { + if (conn->type == CONN_TYPE_OR) { + or_connection_t *or_conn = TO_OR_CONN(conn); + if (!tor_addr_compare(&geoip_ent->addr, &or_conn->real_addr, + CMP_EXACT)) { + or_conn->tracked_for_dos_mitigation = 0; + } + } + } SMARTLIST_FOREACH_END(conn); + + end: + return; +} + /* Note down that we've just refused a single hop client. This increments a * counter later used for the heartbeat. */ void diff --git a/src/or/dos.h b/src/or/dos.h index 56835169d..9ce1baddb 100644 --- a/src/or/dos.h +++ b/src/or/dos.h @@ -43,11 +43,15 @@ typedef struct dos_client_stats_t { /* General API. */ +/* Stub. */ +struct clientmap_entry_t; + void dos_init(void); void dos_free_all(void); void dos_consensus_has_changed(const networkstatus_t *ns); int dos_enabled(void); void dos_log_heartbeat(void); +void dos_geoip_entry_about_to_free(const struct clientmap_entry_t *geoip_ent); void dos_new_client_conn(or_connection_t *or_conn); void dos_close_client_conn(const or_connection_t *or_conn); diff --git a/src/or/geoip.c b/src/or/geoip.c index 5f0b04b56..4e4f6e639 100644 --- a/src/or/geoip.c +++ b/src/or/geoip.c @@ -516,6 +516,10 @@ clientmap_entry_free(clientmap_entry_t *ent) if (!ent) return; + /* This entry is about to be freed so pass it to the DoS subsystem to see if + * any actions can be taken about it. */ + dos_geoip_entry_about_to_free(ent); + tor_free(ent->transport_name); tor_free(ent); }

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[tor/maint-0.3.2] dos: Add a heartbeat log
by nickm＠torproject.org 16 Feb '18

16 Feb '18

commit 14a8b87852887f8c20a424ff32a2b6746105dd6c Author: David Goulet <dgoulet(a)torproject.org> Date: Thu Jan 25 16:36:05 2018 -0500 dos: Add a heartbeat log Signed-off-by: David Goulet <dgoulet(a)torproject.org> --- src/or/dos.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ src/or/dos.h | 1 + src/or/status.c | 2 ++ 3 files changed, 48 insertions(+) diff --git a/src/or/dos.c b/src/or/dos.c index d98d3db16..40e88aead 100644 --- a/src/or/dos.c +++ b/src/or/dos.c @@ -555,6 +555,51 @@ dos_should_refuse_single_hop_client(void) 0 /* default */, 0, 1); } +/* Log a heartbeat message with some statistics. */ +void +dos_log_heartbeat(void) +{ + char *conn_msg = NULL; + char *cc_msg = NULL; + char *single_hop_client_msg = NULL; + + if (!dos_is_enabled()) { + goto end; + } + + if (dos_cc_enabled) { + tor_asprintf(&cc_msg, + " %" PRIu64 " circuits rejected," + " %" PRIu32 " marked addresses.", + cc_num_rejected_cells, cc_num_marked_addrs); + } + + if (dos_conn_enabled) { + tor_asprintf(&conn_msg, + " %" PRIu64 " connections closed.", + conn_num_addr_rejected); + } + + if (dos_should_refuse_single_hop_client()) { + tor_asprintf(&single_hop_client_msg, + " %" PRIu64 " single hop clients refused.", + num_single_hop_client_refused); + } + + log_notice(LD_HEARTBEAT, + "DoS mitigation since startup:%s%s%s", + (cc_msg != NULL) ? cc_msg : " [cc not enabled]", + (conn_msg != NULL) ? conn_msg : " [conn not enabled]", + (single_hop_client_msg != NULL) ? single_hop_client_msg : ""); + + tor_free(conn_msg); + tor_free(cc_msg); + tor_free(single_hop_client_msg); + + end: + return; +} + /* Called when a new client connection has been established on the given * address. */ void diff --git a/src/or/dos.h b/src/or/dos.h index ec4c033ae..56835169d 100644 --- a/src/or/dos.h +++ b/src/or/dos.h @@ -47,6 +47,7 @@ void dos_init(void); void dos_free_all(void); void dos_consensus_has_changed(const networkstatus_t *ns); int dos_enabled(void); +void dos_log_heartbeat(void); void dos_new_client_conn(or_connection_t *or_conn); void dos_close_client_conn(const or_connection_t *or_conn); diff --git a/src/or/status.c b/src/or/status.c index fce6a1015..fa2238b9f 100644 --- a/src/or/status.c +++ b/src/or/status.c @@ -27,6 +27,7 @@ #include "hibernate.h" #include "rephist.h" #include "statefile.h" +#include "dos.h" static void log_accounting(const time_t now, const or_options_t *options); #include "geoip.h" @@ -145,6 +146,7 @@ log_heartbeat(time_t now) if (public_server_mode(options)) { rep_hist_log_circuit_handshake_stats(now); rep_hist_log_link_protocol_counts(); + dos_log_heartbeat(); } circuit_log_ancient_one_hop_circuits(1800);

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[tor/maint-0.3.2] dos: Man page entry for DoS mitigation
by nickm＠torproject.org 16 Feb '18

16 Feb '18

commit a3714268f659998dc879ed723852440cd8be1b04 Author: David Goulet <dgoulet(a)torproject.org> Date: Fri Jan 26 09:00:17 2018 -0500 dos: Man page entry for DoS mitigation Signed-off-by: David Goulet <dgoulet(a)torproject.org> --- doc/tor.1.txt | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 90 insertions(+) diff --git a/doc/tor.1.txt b/doc/tor.1.txt index 4c5d5359a..a2bbb8ab6 100644 --- a/doc/tor.1.txt +++ b/doc/tor.1.txt @@ -2441,6 +2441,96 @@ The following options are used to configure a hidden service. including setting SOCKSPort to "0". (Default: 0) +DENIAL OF SERVICE MITIGATION OPTIONS +------------------------------------ + +The following options are useful only for a public relay. They control the +Denial of Service mitigation subsystem. + +[[DoSCircuitCreationEnabled]] **DoSCircuitCreationEnabled** **0**|**1**|**auto**:: + + Enable circuit creation DoS mitigation. If enabled, tor will cache client + IPs along with statistics in order to detect circuit DoS attacks. If an + address is positively identified, tor will activate defenses against the + address. See the DoSCircuitCreationDefenseType option for more details. + This is a client to relay detection only. "auto" means use the consensus + parameter. + (Default: auto) + +[[DoSCircuitCreationMinConnections]] **DoSCircuitCreationMinConnections** __NUM__:: + + Minimum threshold of concurrent connections before a client address can be + flagged as executing a circuit creation DoS. In other words, once a client + address reaches the circuit rate and has a minimum of NUM concurrent + connections, a detection is positive. "0" means use the consensus + parameter. + (Default: 0) + +[[DoSCircuitCreationRateTenths]] **DoSCircuitCreationRateTenths** __NUM__:: + + The allowed circuit creation rate in tenths of circuit per second applied + per client IP address. For example, if you want to set a rate of 5 + circuits per second allowed per IP address, this value should be set to + 50. If this option is 0, it obeys a consensus parameter. (Default: 0) + +[[DoSCircuitCreationBurst]] **DoSCircuitCreationBurst** __NUM__:: + + The allowed circuit creation burst per client IP address. If the circuit + rate and the burst are reached, a client is marked as executing a circuit + creation DoS. "0" means use the consensus parameter. + (Default: 0) + +[[DoSCircuitCreationDefenseType]] **DoSCircuitCreationDefenseType** __NUM__:: + + This is the type of defense applied to a detected client address. The + possible values are: + + 1: No defense. + 2: Refuse circuit creation for the DoSCircuitCreationDefenseTimePeriod period of time. ++ + "0" means use the consensus parameter. + (Default: 0) + +[[DoSCircuitCreationDefenseTimePeriod]] **DoSCircuitCreationDefenseTimePeriod** __NUM__:: + + The base time period that the DoS defense is activated for. The actual + value is selected randomly for each activation from NUM+1 to 3/2 * NUM. + "0" means use the consensus parameter. + (Default: 0) + +[[DoSConnectionEnabled]] **DoSConnectionEnabled** **0**|**1**|**auto**:: + + Enable the connection DoS mitigation. For client address only, this allows + tor to mitigate against large number of concurrent connections made by a + single IP address. "auto" means use the consensus parameter. + (Default: auto) + +[[DoSConnectionMaxConcurrentCount]] **DoSConnectionMaxConcurrentCount** __NUM__:: + + The maximum threshold of concurrent connection from a client IP address. + Above this limit, a defense selected by DoSConnectionDefenseType is + applied. "0" means use the consensus parameter. + (Default: 0) + +[[DoSConnectionDefenseType]] **DoSConnectionDefenseType** __NUM__:: + + This is the type of defense applied to a detected client address for the + connection mitigation. The possible values are: + + 1: No defense. + 2: Immediately close new connections. ++ + "0" means use the consensus parameter. + (Default: 0) + +[[DoSRefuseSingleHopClientRendezvous]] **DoSRefuseSingleHopClientRendezvous** **0**|**1**|**auto**:: + + Refuse establishment of rendezvous points for single hop clients. In other + words, if a client directly connects to the relay and sends an + ESTABLISH_RENDEZVOUS cell, it is silently dropped. "auto" means use the + consensus parameter. + (Default: auto) + TESTING NETWORK OPTIONS -----------------------

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[tor/maint-0.3.2] channel_tls_get_remote_addr_method now returns real_addr.
by nickm＠torproject.org 16 Feb '18

16 Feb '18

commit 33d9889a2bdd611bcc255c68c43d60b8919ab663 Author: Fernando Fernandez Mancera <ffmancera(a)riseup.net> Date: Mon Jan 22 15:20:17 2018 +0100 channel_tls_get_remote_addr_method now returns real_addr. The accurate address of a connection is real_addr, not the addr member. channel_tls_get_remote_addr_method() now returns real_addr instead. Fixes #24952; bugfix on 707c1e2 in 0.2.4.11-alpha. Signed-off-by: Fernando Fernandez Mancera <ffmancera(a)riseup.net> --- changes/bug24952 | 5 +++++ src/or/channeltls.c | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/changes/bug24952 b/changes/bug24952 new file mode 100644 index 000000000..93174c04f --- /dev/null +++ b/changes/bug24952 @@ -0,0 +1,5 @@ + o Minor bugfix (channel connection): + - The accurate address of a connection is real_addr, not the addr member. + TLS Channel remote address is now real_addr content instead of addr + member. Fixes bug 24952; bugfix on 707c1e2e26 in 0.2.4.11-alpha. + Patch by "ffmancera". diff --git a/src/or/channeltls.c b/src/or/channeltls.c index 09cca95b6..890646989 100644 --- a/src/or/channeltls.c +++ b/src/or/channeltls.c @@ -514,7 +514,7 @@ channel_tls_get_remote_addr_method(channel_t *chan, tor_addr_t *addr_out) tor_assert(addr_out); if (tlschan->conn) { - tor_addr_copy(addr_out, &(TO_CONN(tlschan->conn)->addr)); + tor_addr_copy(addr_out, &(tlschan->conn->real_addr)); rv = 1; } else tor_addr_make_unspec(addr_out);

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[tor/maint-0.3.2] test: Add unit tests for the DoS subsystem
by nickm＠torproject.org 16 Feb '18

16 Feb '18

commit c3c2b55decc80028728780422fe2766ec6517246 Author: George Kadianakis <desnacked(a)riseup.net> Date: Thu Jan 25 16:38:59 2018 -0500 test: Add unit tests for the DoS subsystem Signed-off-by: David Goulet <dgoulet(a)torproject.org> --- src/or/channel.c | 4 +- src/or/channel.h | 3 +- src/test/include.am | 1 + src/test/test.c | 1 + src/test/test.h | 1 + src/test/test_dos.c | 248 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 255 insertions(+), 3 deletions(-) diff --git a/src/or/channel.c b/src/or/channel.c index fdd3f81e8..54e10666d 100644 --- a/src/or/channel.c +++ b/src/or/channel.c @@ -3845,8 +3845,8 @@ channel_get_canonical_remote_descr(channel_t *chan) * supports this operation, and return 1. Return 0 if the underlying transport * doesn't let us do this. */ -int -channel_get_addr_if_possible(channel_t *chan, tor_addr_t *addr_out) +MOCK_IMPL(int, +channel_get_addr_if_possible,(channel_t *chan, tor_addr_t *addr_out)) { tor_assert(chan); tor_assert(addr_out); diff --git a/src/or/channel.h b/src/or/channel.h index a711b56d4..bcd345e8d 100644 --- a/src/or/channel.h +++ b/src/or/channel.h @@ -550,7 +550,8 @@ MOCK_DECL(void, channel_dump_statistics, (channel_t *chan, int severity)); void channel_dump_transport_statistics(channel_t *chan, int severity); const char * channel_get_actual_remote_descr(channel_t *chan); const char * channel_get_actual_remote_address(channel_t *chan); -int channel_get_addr_if_possible(channel_t *chan, tor_addr_t *addr_out); +MOCK_DECL(int, channel_get_addr_if_possible, (channel_t *chan, + tor_addr_t *addr_out)); const char * channel_get_canonical_remote_descr(channel_t *chan); int channel_has_queued_writes(channel_t *chan); int channel_is_bad_for_new_circs(channel_t *chan); diff --git a/src/test/include.am b/src/test/include.am index 8ecfaf10c..91b0a5910 100644 --- a/src/test/include.am +++ b/src/test/include.am @@ -87,6 +87,7 @@ src_test_test_SOURCES = \ src/test/test_controller.c \ src/test/test_controller_events.c \ src/test/test_crypto.c \ + src/test/test_dos.c \ src/test/test_data.c \ src/test/test_dir.c \ src/test/test_dir_common.c \ diff --git a/src/test/test.c b/src/test/test.c index 9a41b976b..f66dee2d0 100644 --- a/src/test/test.c +++ b/src/test/test.c @@ -1197,6 +1197,7 @@ struct testgroup_t testgroups[] = { { "control/", controller_tests }, { "control/event/", controller_event_tests }, { "crypto/", crypto_tests }, + { "dos/", dos_tests }, { "dir/", dir_tests }, { "dir_handle_get/", dir_handle_get_tests }, { "dir/md/", microdesc_tests }, diff --git a/src/test/test.h b/src/test/test.h index 25336ac83..41df6b134 100644 --- a/src/test/test.h +++ b/src/test/test.h @@ -190,6 +190,7 @@ extern struct testcase_t container_tests[]; extern struct testcase_t controller_tests[]; extern struct testcase_t controller_event_tests[]; extern struct testcase_t crypto_tests[]; +extern struct testcase_t dos_tests[]; extern struct testcase_t dir_tests[]; extern struct testcase_t dir_handle_get_tests[]; extern struct testcase_t entryconn_tests[]; diff --git a/src/test/test_dos.c b/src/test/test_dos.c new file mode 100644 index 000000000..5a8474ad8 --- /dev/null +++ b/src/test/test_dos.c @@ -0,0 +1,248 @@ +/* Copyright (c) 2018, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +#define DOS_PRIVATE +#define TOR_CHANNEL_INTERNAL_ +#define CIRCUITLIST_PRIVATE + +#include "or.h" +#include "dos.h" +#include "circuitlist.h" +#include "geoip.h" +#include "channel.h" +#include "test.h" +#include "log_test_helpers.h" + +static unsigned int +mock_enable_dos_protection(const networkstatus_t *ns) +{ + (void) ns; + return 1; +} + +/** Test that the connection tracker of the DoS subsystem will block clients + * who try to establish too many connections */ +static void +test_dos_conn_creation(void *arg) +{ + (void) arg; + + MOCK(get_param_cc_enabled, mock_enable_dos_protection); + MOCK(get_param_conn_enabled, mock_enable_dos_protection); + + /* Initialize test data */ + or_connection_t or_conn; + time_t now = 1281533250; /* 2010-08-11 13:27:30 UTC */ + tt_int_op(AF_INET,OP_EQ, tor_addr_parse(&or_conn.real_addr, + "18.0.0.1")); + tor_addr_t *addr = &or_conn.real_addr; + + /* Get DoS subsystem limits */ + dos_init(); + uint32_t max_concurrent_conns = get_param_conn_max_concurrent_count(NULL); + + /* Introduce new client */ + geoip_note_client_seen(GEOIP_CLIENT_CONNECT, addr, NULL, now); + { /* Register many conns from this client but not enough to get it blocked */ + unsigned int i; + for (i = 0; i < max_concurrent_conns; i++) { + dos_new_client_conn(&or_conn); + } + } + + /* Check that new conns are still permitted */ + tt_int_op(DOS_CONN_DEFENSE_NONE, OP_EQ, + dos_conn_addr_get_defense_type(addr)); + + /* Register another conn and check that new conns are not allowed anymore */ + dos_new_client_conn(&or_conn); + tt_int_op(DOS_CONN_DEFENSE_CLOSE, OP_EQ, + dos_conn_addr_get_defense_type(addr)); + + /* Close a client conn and see that a new conn will be permitted again */ + dos_close_client_conn(&or_conn); + tt_int_op(DOS_CONN_DEFENSE_NONE, OP_EQ, + dos_conn_addr_get_defense_type(addr)); + + /* Register another conn and see that defense measures get reactivated */ + dos_new_client_conn(&or_conn); + tt_int_op(DOS_CONN_DEFENSE_CLOSE, OP_EQ, + dos_conn_addr_get_defense_type(addr)); + + done: + dos_free_all(); +} + +/** Helper mock: Place a fake IP addr for this channel in <b>addr_out</b> */ +static int +mock_channel_get_addr_if_possible(channel_t *chan, tor_addr_t *addr_out) +{ + (void)chan; + tt_int_op(AF_INET,OP_EQ, tor_addr_parse(addr_out, "18.0.0.1"));; + return 1; + + done: + return 0; +} + +/** Test that the circuit tracker of the DoS subsystem will block clients who + * try to establish too many circuits. */ +static void +test_dos_circuit_creation(void *arg) +{ + (void) arg; + unsigned int i; + + MOCK(get_param_cc_enabled, mock_enable_dos_protection); + MOCK(get_param_conn_enabled, mock_enable_dos_protection); + MOCK(channel_get_addr_if_possible, + mock_channel_get_addr_if_possible); + + /* Initialize channels/conns/circs that will be used */ + channel_t *chan = tor_malloc_zero(sizeof(channel_t)); + channel_init(chan); + chan->is_client = 1; + + /* Initialize test data */ + or_connection_t or_conn; + time_t now = 1281533250; /* 2010-08-11 13:27:30 UTC */ + tt_int_op(AF_INET,OP_EQ, tor_addr_parse(&or_conn.real_addr, + "18.0.0.1")); + tor_addr_t *addr = &or_conn.real_addr; + + /* Get DoS subsystem limits */ + dos_init(); + uint32_t max_circuit_count = get_param_cc_circuit_burst(NULL); + uint32_t min_conc_conns_for_cc = + get_param_cc_min_concurrent_connection(NULL); + + /* Introduce new client and establish enough connections to activate the + * circuit counting subsystem */ + geoip_note_client_seen(GEOIP_CLIENT_CONNECT, addr, NULL, now); + for (i = 0; i < min_conc_conns_for_cc ; i++) { + dos_new_client_conn(&or_conn); + } + + /* Register new circuits for this client and conn, but not enough to get + * detected as dos */ + for (i=0; i < max_circuit_count-1; i++) { + dos_cc_new_create_cell(chan); + } + /* see that we didn't get detected for dosing */ + tt_int_op(DOS_CC_DEFENSE_NONE, OP_EQ, dos_cc_get_defense_type(chan)); + + /* Register another CREATE cell that will push us over the limit. Check that + * the cell gets refused. */ + dos_cc_new_create_cell(chan); + tt_int_op(DOS_CC_DEFENSE_REFUSE_CELL, OP_EQ, dos_cc_get_defense_type(chan)); + + /* TODO: Wait a few seconds before sending the cell, and check that the + buckets got refilled properly. */ + /* TODO: Actually send a Tor cell (instead of calling the DoS function) and + * check that it will get refused */ + + done: + tor_free(chan); + dos_free_all(); +} + +/** Test that the DoS subsystem properly refills the circuit token buckets. */ +static void +test_dos_bucket_refill(void *arg) +{ + (void) arg; + int i; + /* For this test, this variable is set to the current circ count of the token + * bucket. */ + uint32_t current_circ_count; + + MOCK(get_param_cc_enabled, mock_enable_dos_protection); + MOCK(get_param_conn_enabled, mock_enable_dos_protection); + MOCK(channel_get_addr_if_possible, + mock_channel_get_addr_if_possible); + + time_t now = 1281533250; /* 2010-08-11 13:27:30 UTC */ + update_approx_time(now); + + /* Initialize channels/conns/circs that will be used */ + channel_t *chan = tor_malloc_zero(sizeof(channel_t)); + channel_init(chan); + chan->is_client = 1; + or_connection_t or_conn; + tt_int_op(AF_INET,OP_EQ, tor_addr_parse(&or_conn.real_addr, + "18.0.0.1")); + tor_addr_t *addr = &or_conn.real_addr; + + /* Initialize DoS subsystem and get relevant limits */ + dos_init(); + uint32_t max_circuit_count = get_param_cc_circuit_burst(NULL); + int circ_rate = tor_lround(get_circuit_rate_per_second()); + /* Check that the circuit rate is a positive number and smaller than the max + * circuit count */ + tt_int_op(circ_rate, OP_GT, 1); + tt_int_op(circ_rate, OP_LT, max_circuit_count); + + /* Register this client */ + geoip_note_client_seen(GEOIP_CLIENT_CONNECT, addr, NULL, now); + dos_new_client_conn(&or_conn); + + /* Fetch this client from the geoip cache and get its DoS structs */ + clientmap_entry_t *entry = geoip_lookup_client(addr, NULL, + GEOIP_CLIENT_CONNECT); + tt_assert(entry); + dos_client_stats_t* dos_stats = &entry->dos_stats; + /* Check that the circuit bucket is still uninitialized */ + tt_uint_op(dos_stats->cc_stats.circuit_bucket, OP_EQ, 0); + + /* Send a create cell: then check that the circ token bucket got initialized + * and one circ was subtracted. */ + dos_cc_new_create_cell(chan); + current_circ_count = max_circuit_count - 1; + tt_uint_op(dos_stats->cc_stats.circuit_bucket, OP_EQ, current_circ_count); + + /* Now send 29 more CREATEs and ensure that the bucket is missing 30 + * tokens */ + for (i=0; i < 29; i++) { + dos_cc_new_create_cell(chan); + current_circ_count--; + } + tt_uint_op(dos_stats->cc_stats.circuit_bucket, OP_EQ, current_circ_count); + + /* OK! Progress time forward one sec, refill the bucket and check that the + * refill happened correctly. */ + now += 1; + update_approx_time(now); + cc_stats_refill_bucket(&dos_stats->cc_stats, addr); + /* check refill */ + current_circ_count += circ_rate; + tt_uint_op(dos_stats->cc_stats.circuit_bucket, OP_EQ, current_circ_count); + + /* Now send as many CREATE cells as needed to deplete our token bucket + * completely */ + for (; current_circ_count != 0; current_circ_count--) { + dos_cc_new_create_cell(chan); + } + tt_uint_op(current_circ_count, OP_EQ, 0); + tt_uint_op(dos_stats->cc_stats.circuit_bucket, OP_EQ, current_circ_count); + + /* Now progress time a week forward, and check that the token bucket does not + * have more than max_circs allowance, even tho we let it simmer for so + * long. */ + now += 604800; /* a week */ + update_approx_time(now); + cc_stats_refill_bucket(&dos_stats->cc_stats, addr); + current_circ_count += max_circuit_count; + tt_uint_op(dos_stats->cc_stats.circuit_bucket, OP_EQ, current_circ_count); + + done: + tor_free(chan); + dos_free_all(); +} + +struct testcase_t dos_tests[] = { + { "conn_creation", test_dos_conn_creation, TT_FORK, NULL, NULL }, + { "circuit_creation", test_dos_circuit_creation, TT_FORK, NULL, NULL }, + { "bucket_refill", test_dos_bucket_refill, TT_FORK, NULL, NULL }, + END_OF_TESTCASES +}; +

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[tor/maint-0.3.2] geoip: Add clientmap_entry_new() function
by nickm＠torproject.org 16 Feb '18

16 Feb '18

commit e758d659a0bc8b9a0e2bd6a0126755fd1fb58e0a Author: David Goulet <dgoulet(a)torproject.org> Date: Fri Feb 2 13:24:37 2018 -0500 geoip: Add clientmap_entry_new() function Signed-off-by: David Goulet <dgoulet(a)torproject.org> --- src/or/geoip.c | 32 ++++++++++++++++++++++++++------ 1 file changed, 26 insertions(+), 6 deletions(-) diff --git a/src/or/geoip.c b/src/or/geoip.c index 92db9742e..76fca43f6 100644 --- a/src/or/geoip.c +++ b/src/or/geoip.c @@ -580,6 +580,31 @@ clientmap_entry_free(clientmap_entry_t *ent) tor_free(ent); } +/* Return a newly allocated clientmap entry with the given action and address + * that are mandatory. The transport_name can be optional. This can't fail. */ +static clientmap_entry_t * +clientmap_entry_new(geoip_client_action_t action, const tor_addr_t *addr, + const char *transport_name) +{ + clientmap_entry_t *entry; + + tor_assert(action == GEOIP_CLIENT_CONNECT || + action == GEOIP_CLIENT_NETWORKSTATUS); + tor_assert(addr); + + entry = tor_malloc_zero(sizeof(clientmap_entry_t)); + entry->action = action; + tor_addr_copy(&entry->addr, addr); + if (transport_name) { + entry->transport_name = tor_strdup(transport_name); + } + + /* Allocated and initialized, note down its size for the OOM handler. */ + geoip_increment_client_history_cache_size(clientmap_entry_size(entry)); + + return entry; +} + /** Clear history of connecting clients used by entry and bridge stats. */ static void client_history_clear(void) @@ -632,13 +657,8 @@ geoip_note_client_seen(geoip_client_action_t action, ent = HT_FIND(clientmap, &client_history, &lookup); if (! ent) { - ent = tor_malloc_zero(sizeof(clientmap_entry_t)); - tor_addr_copy(&ent->addr, addr); - if (transport_name) - ent->transport_name = tor_strdup(transport_name); - ent->action = (int)action; + ent = clientmap_entry_new(action, addr, transport_name); HT_INSERT(clientmap, &client_history, ent); - geoip_increment_client_history_cache_size(clientmap_entry_size(ent)); } if (now / 60 <= (int)MAX_LAST_SEEN_IN_MINUTES && now >= 0) ent->last_seen_in_minutes = (unsigned)(now/60);

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[tor/maint-0.3.2] dos: Make circuit rate limit per second, not tenths anymore
by nickm＠torproject.org 16 Feb '18

16 Feb '18

commit e58a4fc6cfcdeafc2ebfb61fd3cf6d163ce2436c Author: David Goulet <dgoulet(a)torproject.org> Date: Mon Jan 29 11:50:11 2018 -0500 dos: Make circuit rate limit per second, not tenths anymore Because this touches too many commits at once, it is made into one single commit. Remove the use of "tenths" for the circuit rate to simplify things. We can only refill the buckets at best once every second because of the use of approx_time() and our token system is set to be 1 token = 1 circuit so make the rate a flat integer of circuit per second. Signed-off-by: David Goulet <dgoulet(a)torproject.org> --- doc/tor.1.txt | 8 +++----- src/or/config.c | 2 +- src/or/dos.c | 32 ++++++++------------------------ src/or/dos.h | 2 +- src/or/or.h | 5 ++--- 5 files changed, 15 insertions(+), 34 deletions(-) diff --git a/doc/tor.1.txt b/doc/tor.1.txt index a2bbb8ab6..58997cdf3 100644 --- a/doc/tor.1.txt +++ b/doc/tor.1.txt @@ -2466,12 +2466,10 @@ Denial of Service mitigation subsystem. parameter. (Default: 0) -[[DoSCircuitCreationRateTenths]] **DoSCircuitCreationRateTenths** __NUM__:: +[[DoSCircuitCreationRate]] **DoSCircuitCreationRate** __NUM__:: - The allowed circuit creation rate in tenths of circuit per second applied - per client IP address. For example, if you want to set a rate of 5 - circuits per second allowed per IP address, this value should be set to - 50. If this option is 0, it obeys a consensus parameter. (Default: 0) + The allowed circuit creation rate per second applied per client IP + address. If this option is 0, it obeys a consensus parameter. (Default: 0) [[DoSCircuitCreationBurst]] **DoSCircuitCreationBurst** __NUM__:: diff --git a/src/or/config.c b/src/or/config.c index c651c202e..3b4027433 100644 --- a/src/or/config.c +++ b/src/or/config.c @@ -245,7 +245,7 @@ static config_var_t option_vars_[] = { /* DoS circuit creation options. */ V(DoSCircuitCreationEnabled, AUTOBOOL, "auto"), V(DoSCircuitCreationMinConnections, UINT, "0"), - V(DoSCircuitCreationRateTenths, UINT, "0"), + V(DoSCircuitCreationRate, UINT, "0"), V(DoSCircuitCreationBurst, UINT, "0"), V(DoSCircuitCreationDefenseType, INT, "0"), V(DoSCircuitCreationDefenseTimePeriod, INTERVAL, "0"), diff --git a/src/or/dos.c b/src/or/dos.c index 5af75ca57..a614d1231 100644 --- a/src/or/dos.c +++ b/src/or/dos.c @@ -31,7 +31,7 @@ static unsigned int dos_cc_enabled = 0; /* Consensus parameters. They can be changed when a new consensus arrives. * They are initialized with the hardcoded default values. */ static uint32_t dos_cc_min_concurrent_conn; -static uint32_t dos_cc_circuit_rate_tenths; +static uint32_t dos_cc_circuit_rate; static uint32_t dos_cc_circuit_burst; static dos_cc_defense_type_t dos_cc_defense_type; static int32_t dos_cc_defense_time_period; @@ -93,14 +93,14 @@ get_param_cc_min_concurrent_connection(const networkstatus_t *ns) /* Return the parameter for the time rate that is how many circuits over this * time span. */ static uint32_t -get_param_cc_circuit_rate_tenths(const networkstatus_t *ns) +get_param_cc_circuit_rate(const networkstatus_t *ns) { /* This is in seconds. */ - if (get_options()->DoSCircuitCreationRateTenths) { - return get_options()->DoSCircuitCreationRateTenths; + if (get_options()->DoSCircuitCreationRate) { + return get_options()->DoSCircuitCreationRate; } - return networkstatus_get_param(ns, "DoSCircuitCreationRateTenths", - DOS_CC_CIRCUIT_RATE_TENTHS_DEFAULT, + return networkstatus_get_param(ns, "DoSCircuitCreationRate", + DOS_CC_CIRCUIT_RATE_DEFAULT, 1, INT32_MAX); } @@ -189,7 +189,7 @@ set_dos_parameters(const networkstatus_t *ns) /* Get the default consensus param values. */ dos_cc_enabled = get_param_cc_enabled(ns); dos_cc_min_concurrent_conn = get_param_cc_min_concurrent_connection(ns); - dos_cc_circuit_rate_tenths = get_param_cc_circuit_rate_tenths(ns); + dos_cc_circuit_rate = get_param_cc_circuit_rate(ns); dos_cc_circuit_burst = get_param_cc_circuit_burst(ns); dos_cc_defense_time_period = get_param_cc_defense_time_period(ns); dos_cc_defense_type = get_param_cc_defense_type(ns); @@ -225,23 +225,7 @@ cc_consensus_has_changed(const networkstatus_t *ns) STATIC uint32_t get_circuit_rate_per_second(void) { - int64_t circ_rate; - - /* We take the burst divided by the rate which is in tenths of a second so - * convert to get a circuit rate per second. */ - circ_rate = dos_cc_circuit_rate_tenths / 10; - if (circ_rate < 0) { - /* Safety check, never allow it to go below 0 else the bucket will always - * be empty resulting in every address to be detected. */ - circ_rate = 1; - } - - /* Clamp it down to a 32 bit value because a rate of 2^32 circuits per - * second is just too much in any circumstances. */ - if (circ_rate > UINT32_MAX) { - circ_rate = UINT32_MAX; - } - return (uint32_t) circ_rate; + return dos_cc_circuit_rate; } /* Given the circuit creation client statistics object, refill the circuit diff --git a/src/or/dos.h b/src/or/dos.h index 9ce1baddb..8695512ea 100644 --- a/src/or/dos.h +++ b/src/or/dos.h @@ -70,7 +70,7 @@ void dos_note_refuse_single_hop_client(void); /* DoSCircuitCreationMinConnections default */ #define DOS_CC_MIN_CONCURRENT_CONN_DEFAULT 3 /* DoSCircuitCreationRateTenths is 3 per seconds. */ -#define DOS_CC_CIRCUIT_RATE_TENTHS_DEFAULT (3 * 10) +#define DOS_CC_CIRCUIT_RATE_DEFAULT 3 /* DoSCircuitCreationBurst default. */ #define DOS_CC_CIRCUIT_BURST_DEFAULT 90 /* DoSCircuitCreationDefenseTimePeriod in seconds. */ diff --git a/src/or/or.h b/src/or/or.h index 454d05ed5..024a9cff0 100644 --- a/src/or/or.h +++ b/src/or/or.h @@ -4520,9 +4520,8 @@ typedef struct { /** Minimum concurrent connection needed from one single address before any * defense is used. */ int DoSCircuitCreationMinConnections; - /** Circuit rate, in tenths of a second, that is used to refill the token - * bucket at this given rate. */ - int DoSCircuitCreationRateTenths; + /** Circuit rate used to refill the token bucket. */ + int DoSCircuitCreationRate; /** Maximum allowed burst of circuits. Reaching that value, the address is * detected as malicious and a defense might be used. */ int DoSCircuitCreationBurst;

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