/* 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 addr_out */ 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 = 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 };