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-rw-r--r--src/app/config/config.c10
-rw-r--r--src/app/config/or_options_st.h11
-rw-r--r--src/core/or/circuitpadding.c59
-rw-r--r--src/core/or/circuitpadding.h11
-rw-r--r--src/test/test_circuitpadding.c157
-rw-r--r--src/test/test_options.c1
6 files changed, 245 insertions, 4 deletions
diff --git a/src/app/config/config.c b/src/app/config/config.c
index 26a3061a26..e601bb2ecd 100644
--- a/src/app/config/config.c
+++ b/src/app/config/config.c
@@ -597,6 +597,8 @@ static config_var_t option_vars_[] = {
V(ReducedConnectionPadding, BOOL, "0"),
V(ConnectionPadding, AUTOBOOL, "auto"),
V(RefuseUnknownExits, AUTOBOOL, "auto"),
+ V(CircuitPadding, BOOL, "1"),
+ V(ReducedCircuitPadding, BOOL, "0"),
V(RejectPlaintextPorts, CSV, ""),
V(RelayBandwidthBurst, MEMUNIT, "0"),
V(RelayBandwidthRate, MEMUNIT, "0"),
@@ -3744,6 +3746,14 @@ options_validate(or_options_t *old_options, or_options_t *options,
REJECT("Relays cannot set ReducedConnectionPadding. ");
}
+ if (server_mode(options) && options->CircuitPadding == 0) {
+ REJECT("Relays cannot set CircuitPadding to 0. ");
+ }
+
+ if (server_mode(options) && options->ReducedCircuitPadding == 1) {
+ REJECT("Relays cannot set ReducedCircuitPadding. ");
+ }
+
if (options->BridgeDistribution) {
if (!options->BridgeRelay) {
REJECT("You set BridgeDistribution, but you didn't set BridgeRelay!");
diff --git a/src/app/config/or_options_st.h b/src/app/config/or_options_st.h
index bd707fd193..4e03bec7fa 100644
--- a/src/app/config/or_options_st.h
+++ b/src/app/config/or_options_st.h
@@ -248,6 +248,17 @@ struct or_options_t {
* pad to the server regardless of server support. */
int ConnectionPadding;
+ /** Boolean: if true, then circuit padding will be negotiated by client
+ * and server, subject to consenus limits (default). If 0, it will be fully
+ * disabled. */
+ int CircuitPadding;
+
+ /** Boolean: if true, then this client will only use circuit padding
+ * algorithms that are known to use a low amount of overhead. If false,
+ * we will use all available circuit padding algorithms.
+ */
+ int ReducedCircuitPadding;
+
/** To what authority types do we publish our descriptor? Choices are
* "v1", "v2", "v3", "bridge", or "". */
struct smartlist_t *PublishServerDescriptor;
diff --git a/src/core/or/circuitpadding.c b/src/core/or/circuitpadding.c
index 9253c9e282..f21cf113cc 100644
--- a/src/core/or/circuitpadding.c
+++ b/src/core/or/circuitpadding.c
@@ -81,6 +81,8 @@ static void circpad_setup_machine_on_circ(circuit_t *on_circ,
static double circpad_distribution_sample(circpad_distribution_t dist);
/** Cached consensus params */
+static uint8_t circpad_padding_disabled;
+static uint8_t circpad_padding_reduced;
static uint8_t circpad_global_max_padding_percent;
static uint16_t circpad_global_allowed_cells;
static uint16_t circpad_max_circ_queued_cells;
@@ -1081,6 +1083,14 @@ circpad_send_padding_callback(tor_timer_t *timer, void *args,
void
circpad_new_consensus_params(const networkstatus_t *ns)
{
+ circpad_padding_disabled =
+ networkstatus_get_param(ns, "circpad_padding_disabled",
+ 0, 0, 1);
+
+ circpad_padding_reduced =
+ networkstatus_get_param(ns, "circpad_padding_reduced",
+ 0, 0, 1);
+
circpad_global_allowed_cells =
networkstatus_get_param(ns, "circpad_global_allowed_cells",
0, 0, UINT16_MAX-1);
@@ -1095,6 +1105,24 @@ circpad_new_consensus_params(const networkstatus_t *ns)
}
/**
+ * Return true if padding is allowed by torrc and consensus.
+ */
+STATIC bool
+circpad_is_padding_allowed(void)
+{
+ /* If padding has been disabled in the consensus, don't send any more
+ * padding. Technically the machine should be shut down when the next
+ * machine condition check happens, but machine checks only happen on
+ * certain circuit events, and if padding is disabled due to some
+ * network overload or DoS condition, we really want to stop ASAP. */
+ if (circpad_padding_disabled || !get_options()->CircuitPadding) {
+ return 0;
+ }
+
+ return 1;
+}
+
+/**
* Check this machine against its padding limits, as well as global
* consensus limits.
*
@@ -1115,7 +1143,7 @@ circpad_machine_reached_padding_limit(circpad_machine_runtime_t *mi)
/* If machine_padding_pct is non-zero, and we've sent more
* than the allowed count of padding cells, then check our
* percent limits for this machine. */
- if (machine->max_padding_percent &&
+ if (machine->max_padding_percent &&
mi->padding_sent >= machine->allowed_padding_count) {
uint32_t total_cells = mi->padding_sent + mi->nonpadding_sent;
@@ -1162,6 +1190,18 @@ circpad_machine_schedule_padding,(circpad_machine_runtime_t *mi))
struct timeval timeout;
tor_assert(mi);
+ /* Don't schedule padding if it is disabled */
+ if (!circpad_is_padding_allowed()) {
+ static ratelim_t padding_lim = RATELIM_INIT(600);
+ log_fn_ratelim(&padding_lim,LOG_INFO,LD_CIRC,
+ "Padding has been disabled, but machine still on circuit %"PRIu64
+ ", %d",
+ mi->on_circ->n_chan ? mi->on_circ->n_chan->global_identifier : 0,
+ mi->on_circ->n_circ_id);
+
+ return CIRCPAD_STATE_UNCHANGED;
+ }
+
/* Don't schedule padding if we are currently in dormant mode. */
if (!is_participating_on_network()) {
log_info(LD_CIRC, "Not scheduling padding because we are dormant.");
@@ -1182,7 +1222,8 @@ circpad_machine_schedule_padding,(circpad_machine_runtime_t *mi))
"Padding machine has reached padding limit on circuit %u",
TO_ORIGIN_CIRCUIT(mi->on_circ)->global_identifier);
} else {
- log_fn(LOG_INFO, LD_CIRC,
+ static ratelim_t padding_lim = RATELIM_INIT(600);
+ log_fn_ratelim(&padding_lim,LOG_INFO,LD_CIRC,
"Padding machine has reached padding limit on circuit %"PRIu64
", %d",
mi->on_circ->n_chan ? mi->on_circ->n_chan->global_identifier : 0,
@@ -1621,6 +1662,19 @@ static inline bool
circpad_machine_conditions_met(origin_circuit_t *circ,
const circpad_machine_spec_t *machine)
{
+ /* If padding is disabled, no machines should match/apply. This has
+ * the effect of shutting down all machines, and not adding any more. */
+ if (circpad_padding_disabled || !get_options()->CircuitPadding)
+ return 0;
+
+ /* If the consensus or our torrc has selected reduced connection padding,
+ * then only allow this machine if it is flagged as acceptable under
+ * reduced padding conditions */
+ if (circpad_padding_reduced || get_options()->ReducedCircuitPadding) {
+ if (!machine->conditions.reduced_padding_ok)
+ return 0;
+ }
+
if (!(circpad_circ_purpose_to_mask(TO_CIRCUIT(circ)->purpose)
& machine->conditions.purpose_mask))
return 0;
@@ -2166,6 +2220,7 @@ circpad_circ_client_machine_init(void)
circ_client_machine->conditions.state_mask =
CIRCPAD_CIRC_BUILDING|CIRCPAD_CIRC_OPENED|CIRCPAD_CIRC_HAS_RELAY_EARLY;
circ_client_machine->conditions.purpose_mask = CIRCPAD_PURPOSE_ALL;
+ circ_client_machine->conditions.reduced_padding_ok = 1;
circ_client_machine->target_hopnum = 2;
circ_client_machine->is_origin_side = 1;
diff --git a/src/core/or/circuitpadding.h b/src/core/or/circuitpadding.h
index bc2522c210..f00369eb0a 100644
--- a/src/core/or/circuitpadding.h
+++ b/src/core/or/circuitpadding.h
@@ -152,6 +152,17 @@ typedef struct circpad_machine_conditions_t {
/** Only apply the machine *if* vanguards are enabled */
unsigned requires_vanguards : 1;
+ /**
+ * This machine is ok to use if reduced padding is set in consensus
+ * or torrc. This machine will still be applied even if reduced padding
+ * is not set; this flag only acts to exclude machines that don't have
+ * it set when reduced padding is requested. Therefore, reduced padding
+ * machines should appear at the lowest priority in the padding machine
+ * lists (aka first in the list), so that non-reduced padding machines
+ * for the same purpose are given a chance to apply when reduced padding
+ * is not requested. */
+ unsigned reduced_padding_ok : 1;
+
/** Only apply the machine *if* the circuit's state matches any of
* the bits set in this bitmask. */
circpad_circuit_state_t state_mask;
diff --git a/src/test/test_circuitpadding.c b/src/test/test_circuitpadding.c
index 914bcb97d7..db175fecee 100644
--- a/src/test/test_circuitpadding.c
+++ b/src/test/test_circuitpadding.c
@@ -1685,8 +1685,11 @@ static void
helper_create_conditional_machines(void)
{
circpad_machine_spec_t *add = helper_create_conditional_machine();
- origin_padding_machines = smartlist_new();
- relay_padding_machines = smartlist_new();
+
+ if (!origin_padding_machines)
+ origin_padding_machines = smartlist_new();
+ if (!relay_padding_machines)
+ relay_padding_machines = smartlist_new();
add->machine_num = 2;
add->is_origin_side = 1;
@@ -2398,6 +2401,155 @@ test_circuitpadding_global_rate_limiting(void *arg)
smartlist_free(vote1.net_params);
}
+/* Test reduced and disabled padding */
+static void
+test_circuitpadding_reduce_disable(void *arg)
+{
+ (void) arg;
+ int64_t actual_mocked_monotime_start;
+
+ MOCK(circuitmux_attach_circuit, circuitmux_attach_circuit_mock);
+
+ nodes_init();
+ dummy_channel.cmux = circuitmux_alloc();
+ relay_side = (circuit_t *)new_fake_orcirc(&dummy_channel,
+ &dummy_channel);
+ client_side = (circuit_t *)origin_circuit_new();
+ relay_side->purpose = CIRCUIT_PURPOSE_OR;
+ client_side->purpose = CIRCUIT_PURPOSE_C_GENERAL;
+
+ circpad_machines_init();
+ helper_create_conditional_machines();
+
+ monotime_init();
+ monotime_enable_test_mocking();
+ actual_mocked_monotime_start = MONOTIME_MOCK_START;
+ monotime_set_mock_time_nsec(actual_mocked_monotime_start);
+ monotime_coarse_set_mock_time_nsec(actual_mocked_monotime_start);
+ curr_mocked_time = actual_mocked_monotime_start;
+ timers_initialize();
+
+ /* This is needed so that we are not considered to be dormant */
+ note_user_activity(20);
+
+ MOCK(circuit_package_relay_cell,
+ circuit_package_relay_cell_mock);
+ MOCK(node_get_by_id,
+ node_get_by_id_mock);
+
+ /* Simulate extend. This should result in the original machine getting
+ * added, since the circuit is not built */
+ simulate_single_hop_extend(client_side, relay_side, 1);
+ simulate_single_hop_extend(client_side, relay_side, 1);
+
+ /* Verify that machine #2 is added */
+ tt_int_op(client_side->padding_machine[0]->machine_num, OP_EQ, 2);
+ tt_int_op(relay_side->padding_machine[0]->machine_num, OP_EQ, 2);
+
+ /* Deliver a padding cell to the client, to trigger burst state */
+ circpad_cell_event_padding_sent(client_side);
+
+ /* This should have trigger length shutdown condition on client.. */
+ tt_ptr_op(client_side->padding_info[0], OP_EQ, NULL);
+ tt_ptr_op(client_side->padding_machine[0], OP_EQ, NULL);
+
+ /* Verify machine is gone from both sides */
+ tt_ptr_op(relay_side->padding_info[0], OP_EQ, NULL);
+ tt_ptr_op(relay_side->padding_machine[0], OP_EQ, NULL);
+
+ /* Now test the reduced padding machine by setting up the consensus */
+ networkstatus_t vote1;
+ vote1.net_params = smartlist_new();
+ smartlist_split_string(vote1.net_params,
+ "circpad_padding_reduced=1", NULL, 0, 0);
+
+ /* Register reduced padding machine with the padding subsystem */
+ circpad_new_consensus_params(&vote1);
+
+ simulate_single_hop_extend(client_side, relay_side, 1);
+
+ /* Verify that machine #0 is added */
+ tt_int_op(client_side->padding_machine[0]->machine_num, OP_EQ, 0);
+ tt_int_op(relay_side->padding_machine[0]->machine_num, OP_EQ, 0);
+
+ tt_int_op(
+ circpad_machine_reached_padding_limit(client_side->padding_info[0]),
+ OP_EQ, 0);
+ tt_int_op(
+ circpad_machine_reached_padding_limit(relay_side->padding_info[0]),
+ OP_EQ, 0);
+
+ /* Test that machines get torn down when padding is disabled */
+ SMARTLIST_FOREACH(vote1.net_params, char *, cp, tor_free(cp));
+ smartlist_free(vote1.net_params);
+ vote1.net_params = smartlist_new();
+ smartlist_split_string(vote1.net_params,
+ "circpad_padding_disabled=1", NULL, 0, 0);
+
+ /* Register reduced padding machine with the padding subsystem */
+ circpad_new_consensus_params(&vote1);
+
+ tt_int_op(
+ circpad_machine_schedule_padding(client_side->padding_info[0]),
+ OP_EQ, CIRCPAD_STATE_UNCHANGED);
+ tt_int_op(
+ circpad_machine_schedule_padding(relay_side->padding_info[0]),
+ OP_EQ, CIRCPAD_STATE_UNCHANGED);
+
+ /* Signal that circuit is built: this event causes us to re-evaluate
+ * machine conditions (which don't apply because padding is disabled). */
+ circpad_machine_event_circ_built(TO_ORIGIN_CIRCUIT(client_side));
+
+ tt_ptr_op(client_side->padding_info[0], OP_EQ, NULL);
+ tt_ptr_op(client_side->padding_machine[0], OP_EQ, NULL);
+ tt_ptr_op(relay_side->padding_info[0], OP_EQ, NULL);
+ tt_ptr_op(relay_side->padding_machine[0], OP_EQ, NULL);
+
+ SMARTLIST_FOREACH(vote1.net_params, char *, cp, tor_free(cp));
+ smartlist_free(vote1.net_params);
+ vote1.net_params = NULL;
+ circpad_new_consensus_params(&vote1);
+
+ get_options_mutable()->ReducedCircuitPadding = 1;
+
+ simulate_single_hop_extend(client_side, relay_side, 1);
+
+ /* Verify that machine #0 is added */
+ tt_int_op(client_side->padding_machine[0]->machine_num, OP_EQ, 0);
+ tt_int_op(relay_side->padding_machine[0]->machine_num, OP_EQ, 0);
+
+ tt_int_op(
+ circpad_machine_reached_padding_limit(client_side->padding_info[0]),
+ OP_EQ, 0);
+ tt_int_op(
+ circpad_machine_reached_padding_limit(relay_side->padding_info[0]),
+ OP_EQ, 0);
+
+ get_options_mutable()->CircuitPadding = 0;
+
+ tt_int_op(
+ circpad_machine_schedule_padding(client_side->padding_info[0]),
+ OP_EQ, CIRCPAD_STATE_UNCHANGED);
+ tt_int_op(
+ circpad_machine_schedule_padding(relay_side->padding_info[0]),
+ OP_EQ, CIRCPAD_STATE_UNCHANGED);
+
+ /* Signal that circuit is built: this event causes us to re-evaluate
+ * machine conditions (which don't apply because padding is disabled). */
+
+ circpad_machine_event_circ_built(TO_ORIGIN_CIRCUIT(client_side));
+
+ tt_ptr_op(client_side->padding_info[0], OP_EQ, NULL);
+ tt_ptr_op(client_side->padding_machine[0], OP_EQ, NULL);
+ tt_ptr_op(relay_side->padding_info[0], OP_EQ, NULL);
+ tt_ptr_op(relay_side->padding_machine[0], OP_EQ, NULL);
+
+ done:
+ free_fake_orcirc(relay_side);
+ circuitmux_detach_all_circuits(dummy_channel.cmux, NULL);
+ circuitmux_free(dummy_channel.cmux);
+}
+
#define TEST_CIRCUITPADDING(name, flags) \
{ #name, test_##name, (flags), NULL, NULL }
@@ -2412,6 +2564,7 @@ struct testcase_t circuitpadding_tests[] = {
TEST_CIRCUITPADDING(circuitpadding_sample_distribution, TT_FORK),
TEST_CIRCUITPADDING(circuitpadding_machine_rate_limiting, TT_FORK),
TEST_CIRCUITPADDING(circuitpadding_global_rate_limiting, TT_FORK),
+ TEST_CIRCUITPADDING(circuitpadding_reduce_disable, TT_FORK),
TEST_CIRCUITPADDING(circuitpadding_token_removal_lower, TT_FORK),
TEST_CIRCUITPADDING(circuitpadding_token_removal_higher, TT_FORK),
TEST_CIRCUITPADDING(circuitpadding_closest_token_removal, TT_FORK),
diff --git a/src/test/test_options.c b/src/test/test_options.c
index f12e6b6763..396be6b18d 100644
--- a/src/test/test_options.c
+++ b/src/test/test_options.c
@@ -430,6 +430,7 @@ get_options_test_data(const char *conf)
// Being kinda lame and just fixing the immedate breakage for now..
result->opt->ConnectionPadding = -1; // default must be "auto"
result->opt->DormantClientTimeout = 1800; // must be over 600.
+ result->opt->CircuitPadding = 1; // default must be "1"
rv = config_get_lines(conf, &cl, 1);
tt_int_op(rv, OP_EQ, 0);
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