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-rw-r--r--src/or/circuitbuild.c272
1 files changed, 125 insertions, 147 deletions
diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 5f1f8122fd..6881e0ebb8 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -43,7 +43,7 @@
#include "connection_edge.h"
#include "connection_or.h"
#include "control.h"
-#include "crypto.h"
+#include "crypto_rand.h"
#include "directory.h"
#include "entrynodes.h"
#include "hs_ntor.h"
@@ -56,6 +56,7 @@
#include "onion_fast.h"
#include "policies.h"
#include "relay.h"
+#include "relay_crypto.h"
#include "rendcommon.h"
#include "rephist.h"
#include "router.h"
@@ -71,10 +72,7 @@ static channel_t * channel_connect_for_circuit(const tor_addr_t *addr,
static int circuit_deliver_create_cell(circuit_t *circ,
const create_cell_t *create_cell,
int relayed);
-static int onion_pick_cpath_exit(origin_circuit_t *circ, extend_info_t *exit,
- int is_hs_v3_rp_circuit);
static crypt_path_t *onion_next_hop_in_cpath(crypt_path_t *cpath);
-static int onion_extend_cpath(origin_circuit_t *circ);
STATIC int onion_append_hop(crypt_path_t **head_ptr, extend_info_t *choice);
static int circuit_send_first_onion_skin(origin_circuit_t *circ);
static int circuit_build_no_more_hops(origin_circuit_t *circ);
@@ -417,7 +415,7 @@ onion_populate_cpath(origin_circuit_t *circ)
circ->cpath->extend_info->identity_digest);
/* If we don't know the node and its descriptor, we must be bootstrapping.
*/
- if (!node || !node_has_descriptor(node)) {
+ if (!node || !node_has_preferred_descriptor(node, 1)) {
return 0;
}
}
@@ -1055,7 +1053,7 @@ circuit_build_no_more_hops(origin_circuit_t *circ)
clear_broken_connection_map(1);
if (server_mode(options) && !check_whether_orport_reachable(options)) {
inform_testing_reachability();
- consider_testing_reachability(1, 1);
+ router_do_reachability_checks(1, 1);
}
}
@@ -1336,69 +1334,10 @@ circuit_init_cpath_crypto(crypt_path_t *cpath,
const char *key_data, size_t key_data_len,
int reverse, int is_hs_v3)
{
- crypto_digest_t *tmp_digest;
- crypto_cipher_t *tmp_crypto;
- size_t digest_len = 0;
- size_t cipher_key_len = 0;
tor_assert(cpath);
- tor_assert(key_data);
- tor_assert(!(cpath->f_crypto || cpath->b_crypto ||
- cpath->f_digest || cpath->b_digest));
-
- /* Basic key size validation */
- if (is_hs_v3 && BUG(key_data_len != HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN)) {
- return -1;
- } else if (!is_hs_v3 && BUG(key_data_len != CPATH_KEY_MATERIAL_LEN)) {
- return -1;
- }
-
- /* If we are using this cpath for next gen onion services use SHA3-256,
- otherwise use good ol' SHA1 */
- if (is_hs_v3) {
- digest_len = DIGEST256_LEN;
- cipher_key_len = CIPHER256_KEY_LEN;
- cpath->f_digest = crypto_digest256_new(DIGEST_SHA3_256);
- cpath->b_digest = crypto_digest256_new(DIGEST_SHA3_256);
- } else {
- digest_len = DIGEST_LEN;
- cipher_key_len = CIPHER_KEY_LEN;
- cpath->f_digest = crypto_digest_new();
- cpath->b_digest = crypto_digest_new();
- }
-
- tor_assert(digest_len != 0);
- tor_assert(cipher_key_len != 0);
- const int cipher_key_bits = (int) cipher_key_len * 8;
-
- crypto_digest_add_bytes(cpath->f_digest, key_data, digest_len);
- crypto_digest_add_bytes(cpath->b_digest, key_data+digest_len, digest_len);
-
- cpath->f_crypto = crypto_cipher_new_with_bits(key_data+(2*digest_len),
- cipher_key_bits);
- if (!cpath->f_crypto) {
- log_warn(LD_BUG,"Forward cipher initialization failed.");
- return -1;
- }
-
- cpath->b_crypto = crypto_cipher_new_with_bits(
- key_data+(2*digest_len)+cipher_key_len,
- cipher_key_bits);
- if (!cpath->b_crypto) {
- log_warn(LD_BUG,"Backward cipher initialization failed.");
- return -1;
- }
-
- if (reverse) {
- tmp_digest = cpath->f_digest;
- cpath->f_digest = cpath->b_digest;
- cpath->b_digest = tmp_digest;
- tmp_crypto = cpath->f_crypto;
- cpath->f_crypto = cpath->b_crypto;
- cpath->b_crypto = tmp_crypto;
- }
-
- return 0;
+ return relay_crypto_init(&cpath->crypto, key_data, key_data_len, reverse,
+ is_hs_v3);
}
/** A "created" cell <b>reply</b> came back to us on circuit <b>circ</b>.
@@ -1521,7 +1460,6 @@ onionskin_answer(or_circuit_t *circ,
const uint8_t *rend_circ_nonce)
{
cell_t cell;
- crypt_path_t *tmp_cpath;
tor_assert(keys_len == CPATH_KEY_MATERIAL_LEN);
@@ -1532,25 +1470,15 @@ onionskin_answer(or_circuit_t *circ,
}
cell.circ_id = circ->p_circ_id;
- tmp_cpath = tor_malloc_zero(sizeof(crypt_path_t));
- tmp_cpath->magic = CRYPT_PATH_MAGIC;
-
circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_OPEN);
log_debug(LD_CIRC,"init digest forward 0x%.8x, backward 0x%.8x.",
(unsigned int)get_uint32(keys),
(unsigned int)get_uint32(keys+20));
- if (circuit_init_cpath_crypto(tmp_cpath, keys, keys_len, 0, 0)<0) {
+ if (relay_crypto_init(&circ->crypto, keys, keys_len, 0, 0)<0) {
log_warn(LD_BUG,"Circuit initialization failed");
- tor_free(tmp_cpath);
return -1;
}
- circ->n_digest = tmp_cpath->f_digest;
- circ->n_crypto = tmp_cpath->f_crypto;
- circ->p_digest = tmp_cpath->b_digest;
- circ->p_crypto = tmp_cpath->b_crypto;
- tmp_cpath->magic = 0;
- tor_free(tmp_cpath);
memcpy(circ->rend_circ_nonce, rend_circ_nonce, DIGEST_LEN);
@@ -1611,7 +1539,7 @@ onionskin_answer(or_circuit_t *circ,
* rend_service_launch_establish_intro())
*
* - We are a router testing its own reachabiity
- * (CIRCUIT_PURPOSE_TESTING, via consider_testing_reachability())
+ * (CIRCUIT_PURPOSE_TESTING, via router_do_reachability_checks())
*
* onion_pick_cpath_exit() bypasses us (by not calling
* new_route_len()) in the one-hop tunnel case, so we don't need to
@@ -1827,7 +1755,7 @@ ap_stream_wants_exit_attention(connection_t *conn)
* Return NULL if we can't find any suitable routers.
*/
static const node_t *
-choose_good_exit_server_general(int need_uptime, int need_capacity)
+choose_good_exit_server_general(router_crn_flags_t flags)
{
int *n_supported;
int n_pending_connections = 0;
@@ -1837,6 +1765,9 @@ choose_good_exit_server_general(int need_uptime, int need_capacity)
const or_options_t *options = get_options();
const smartlist_t *the_nodes;
const node_t *selected_node=NULL;
+ const int need_uptime = (flags & CRN_NEED_UPTIME) != 0;
+ const int need_capacity = (flags & CRN_NEED_CAPACITY) != 0;
+ const int direct_conn = (flags & CRN_DIRECT_CONN) != 0;
connections = get_connection_array();
@@ -1869,7 +1800,7 @@ choose_good_exit_server_general(int need_uptime, int need_capacity)
*/
continue;
}
- if (!node_has_descriptor(node)) {
+ if (!node_has_preferred_descriptor(node, direct_conn)) {
n_supported[i] = -1;
continue;
}
@@ -1982,7 +1913,8 @@ choose_good_exit_server_general(int need_uptime, int need_capacity)
need_capacity?", fast":"",
need_uptime?", stable":"");
tor_free(n_supported);
- return choose_good_exit_server_general(0, 0);
+ flags &= ~(CRN_NEED_UPTIME|CRN_NEED_CAPACITY);
+ return choose_good_exit_server_general(flags);
}
log_notice(LD_CIRC, "All routers are down or won't exit%s -- "
"choosing a doomed exit at random.",
@@ -2229,17 +2161,11 @@ pick_restricted_middle_node(router_crn_flags_t flags,
* toward the preferences in 'options'.
*/
static const node_t *
-choose_good_exit_server(origin_circuit_t *circ, int need_uptime,
- int need_capacity, int is_internal, int need_hs_v3)
+choose_good_exit_server(origin_circuit_t *circ,
+ router_crn_flags_t flags, int is_internal)
{
const or_options_t *options = get_options();
- router_crn_flags_t flags = CRN_NEED_DESC;
- if (need_uptime)
- flags |= CRN_NEED_UPTIME;
- if (need_capacity)
- flags |= CRN_NEED_CAPACITY;
- if (need_hs_v3)
- flags |= CRN_RENDEZVOUS_V3;
+ flags |= CRN_NEED_DESC;
switch (TO_CIRCUIT(circ)->purpose) {
case CIRCUIT_PURPOSE_C_HSDIR_GET:
@@ -2253,7 +2179,7 @@ choose_good_exit_server(origin_circuit_t *circ, int need_uptime,
if (is_internal) /* pick it like a middle hop */
return router_choose_random_node(NULL, options->ExcludeNodes, flags);
else
- return choose_good_exit_server_general(need_uptime,need_capacity);
+ return choose_good_exit_server_general(flags);
case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
{
/* Pick a new RP */
@@ -2354,7 +2280,7 @@ warn_if_last_router_excluded(origin_circuit_t *circ,
* be used as an HS v3 rendezvous point.
*
* Return 0 if ok, -1 if circuit should be closed. */
-static int
+STATIC int
onion_pick_cpath_exit(origin_circuit_t *circ, extend_info_t *exit_ei,
int is_hs_v3_rp_circuit)
{
@@ -2378,15 +2304,22 @@ onion_pick_cpath_exit(origin_circuit_t *circ, extend_info_t *exit_ei,
extend_info_describe(exit_ei));
exit_ei = extend_info_dup(exit_ei);
} else { /* we have to decide one */
+ router_crn_flags_t flags = CRN_NEED_DESC;
+ if (state->need_uptime)
+ flags |= CRN_NEED_UPTIME;
+ if (state->need_capacity)
+ flags |= CRN_NEED_CAPACITY;
+ if (is_hs_v3_rp_circuit)
+ flags |= CRN_RENDEZVOUS_V3;
+ if (state->onehop_tunnel)
+ flags |= CRN_DIRECT_CONN;
const node_t *node =
- choose_good_exit_server(circ, state->need_uptime,
- state->need_capacity, state->is_internal,
- is_hs_v3_rp_circuit);
+ choose_good_exit_server(circ, flags, state->is_internal);
if (!node) {
log_warn(LD_CIRC,"Failed to choose an exit server");
return -1;
}
- exit_ei = extend_info_from_node(node, 0);
+ exit_ei = extend_info_from_node(node, state->onehop_tunnel);
if (BUG(exit_ei == NULL))
return -1;
}
@@ -2443,6 +2376,10 @@ circuit_extend_to_new_exit(origin_circuit_t *circ, extend_info_t *exit_ei)
/** Return the number of routers in <b>routers</b> that are currently up
* and available for building circuits through.
+ *
+ * (Note that this function may overcount or undercount, if we have
+ * descriptors that are not the type we would prefer to use for some
+ * particular router. See bug #25885.)
*/
MOCK_IMPL(STATIC int,
count_acceptable_nodes, (smartlist_t *nodes))
@@ -2459,7 +2396,7 @@ count_acceptable_nodes, (smartlist_t *nodes))
if (! node->is_valid)
// log_debug(LD_CIRC,"Nope, the directory says %d is not valid.",i);
continue;
- if (! node_has_descriptor(node))
+ if (! node_has_any_descriptor(node))
continue;
/* The node has a descriptor, so we can just check the ntor key directly */
if (!node_has_curve25519_onion_key(node))
@@ -2514,12 +2451,71 @@ cpath_get_n_hops(crypt_path_t **head_ptr)
#endif /* defined(TOR_UNIT_TESTS) */
/**
+ * Build the exclude list for vanguard circuits.
+ *
+ * For vanguard circuits we exclude all the already chosen nodes (including the
+ * exit) from being middle hops to prevent the creation of A - B - A subpaths.
+ * We also allow the 4th hop to be the same as the guard node so as to not leak
+ * guard information to RP/IP/HSDirs.
+ *
+ * For vanguard circuits, we don't apply any subnet or family restrictions.
+ * This is to avoid impossible-to-build circuit paths, or just situations where
+ * our earlier guards prevent us from using most of our later ones.
+ *
+ * The alternative is building the circuit in reverse. Reverse calls to
+ * onion_extend_cpath() (ie: select outer hops first) would then have the
+ * property that you don't gain information about inner hops by observing
+ * outer ones. See https://trac.torproject.org/projects/tor/ticket/24487
+ * for this.
+ *
+ * (Note further that we still exclude the exit to prevent A - B - A
+ * at the end of the path. */
+static smartlist_t *
+build_vanguard_middle_exclude_list(uint8_t purpose,
+ cpath_build_state_t *state,
+ crypt_path_t *head,
+ int cur_len)
+{
+ smartlist_t *excluded;
+ const node_t *r;
+ crypt_path_t *cpath;
+ int i;
+
+ (void) purpose;
+
+ excluded = smartlist_new();
+
+ /* Add the exit to the exclude list (note that the exit/last hop is always
+ * chosen first in circuit_establish_circuit()). */
+ if ((r = build_state_get_exit_node(state))) {
+ smartlist_add(excluded, (node_t*)r);
+ }
+
+ /* If we are picking the 4th hop, allow that node to be the guard too.
+ * This prevents us from avoiding the Guard for those hops, which
+ * gives the adversary information about our guard if they control
+ * the RP, IP, or HSDIR. We don't do this check based on purpose
+ * because we also want to allow HS_VANGUARDS pre-build circuits
+ * to use the guard for that last hop.
+ */
+ if (cur_len == DEFAULT_ROUTE_LEN+1) {
+ /* Skip the first hop for the exclude list below */
+ head = head->next;
+ cur_len--;
+ }
+
+ for (i = 0, cpath = head; cpath && i < cur_len; ++i, cpath=cpath->next) {
+ if ((r = node_get_by_id(cpath->extend_info->identity_digest))) {
+ smartlist_add(excluded, (node_t*)r);
+ }
+ }
+
+ return excluded;
+}
+
+/**
* Build a list of nodes to exclude from the choice of this middle
* hop, based on already chosen nodes.
- *
- * XXX: At present, this function does not exclude any nodes from
- * the vanguard circuits. See
- * https://trac.torproject.org/projects/tor/ticket/24487
*/
static smartlist_t *
build_middle_exclude_list(uint8_t purpose,
@@ -2532,32 +2528,21 @@ build_middle_exclude_list(uint8_t purpose,
crypt_path_t *cpath;
int i;
+ /** Vanguard circuits have their own path selection rules */
+ if (circuit_should_use_vanguards(purpose)) {
+ return build_vanguard_middle_exclude_list(purpose, state, head, cur_len);
+ }
+
excluded = smartlist_new();
- /* Add the exit to the exclude list (note that the exit/last hop is always
- * chosen first in circuit_establish_circuit()). */
+ /* For non-vanguard circuits, add the exit and its family to the exclude list
+ * (note that the exit/last hop is always chosen first in
+ * circuit_establish_circuit()). */
if ((r = build_state_get_exit_node(state))) {
nodelist_add_node_and_family(excluded, r);
}
- /* XXX: We don't apply any other previously selected node restrictions for
- * vanguards, and allow nodes to be reused for those hop positions in the
- * same circuit. This is because after many rotations, you get to learn
- * inner guard nodes through the nodes that are not selected for outer
- * hops.
- *
- * The alternative is building the circuit in reverse. Reverse calls to
- * onion_extend_cpath() (ie: select outer hops first) would then have the
- * property that you don't gain information about inner hops by observing
- * outer ones. See https://trac.torproject.org/projects/tor/ticket/24487
- * for this.
- *
- * (Note further that we can and do still exclude the exit in the block
- * above, because it is chosen first in circuit_establish_circuit()..) */
- if (circuit_should_use_vanguards(purpose)) {
- return excluded;
- }
-
+ /* also exclude all other already chosen nodes and their family */
for (i = 0, cpath = head; cpath && i < cur_len; ++i, cpath=cpath->next) {
if ((r = node_get_by_id(cpath->extend_info->identity_digest))) {
nodelist_add_node_and_family(excluded, r);
@@ -2657,7 +2642,9 @@ choose_good_middle_server(uint8_t purpose,
/** If a hidden service circuit wants a specific middle node, pin it. */
if (middle_node_must_be_vanguard(options, purpose, cur_len)) {
log_debug(LD_GENERAL, "Picking a sticky node (cur_len = %d)", cur_len);
- return pick_vanguard_middle_node(options, flags, cur_len, excluded);
+ choice = pick_vanguard_middle_node(options, flags, cur_len, excluded);
+ smartlist_free(excluded);
+ return choice;
}
choice = router_choose_random_node(excluded, options->ExcludeNodes, flags);
@@ -2697,7 +2684,7 @@ choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state,
/* This request is for an entry server to use for a regular circuit,
* and we use entry guard nodes. Just return one of the guard nodes. */
tor_assert(guard_state_out);
- return guards_choose_guard(state, guard_state_out);
+ return guards_choose_guard(state, purpose, guard_state_out);
}
excluded = smartlist_new();
@@ -2740,7 +2727,7 @@ onion_next_hop_in_cpath(crypt_path_t *cpath)
* Return 1 if the path is complete, 0 if we successfully added a hop,
* and -1 on error.
*/
-static int
+STATIC int
onion_extend_cpath(origin_circuit_t *circ)
{
uint8_t purpose = circ->base_.purpose;
@@ -2847,9 +2834,10 @@ extend_info_new(const char *nickname,
* of the node (i.e. its IPv4 address) unless
* <b>for_direct_connect</b> is true, in which case the preferred
* address is used instead. May return NULL if there is not enough
- * info about <b>node</b> to extend to it--for example, if there is no
- * routerinfo_t or microdesc_t, or if for_direct_connect is true and none of
- * the node's addresses are allowed by tor's firewall and IP version config.
+ * info about <b>node</b> to extend to it--for example, if the preferred
+ * routerinfo_t or microdesc_t is missing, or if for_direct_connect is
+ * true and none of the node's addresses is allowed by tor's firewall
+ * and IP version config.
**/
extend_info_t *
extend_info_from_node(const node_t *node, int for_direct_connect)
@@ -2857,27 +2845,17 @@ extend_info_from_node(const node_t *node, int for_direct_connect)
tor_addr_port_t ap;
int valid_addr = 0;
- const int is_bridge = node_is_a_configured_bridge(node);
- const int we_use_mds = we_use_microdescriptors_for_circuits(get_options());
-
- if ((is_bridge && for_direct_connect) || !we_use_mds) {
- /* We need an ri in this case. */
- if (!node->ri)
- return NULL;
- } else {
- /* Otherwise we need an md. */
- if (node->rs == NULL || node->md == NULL)
- return NULL;
+ if (!node_has_preferred_descriptor(node, for_direct_connect)) {
+ return NULL;
}
- /* Choose a preferred address first, but fall back to an allowed address.
- * choose_address returns 1 on success, but get_prim_orport returns 0. */
+ /* Choose a preferred address first, but fall back to an allowed address. */
if (for_direct_connect)
- valid_addr = fascist_firewall_choose_address_node(node,
- FIREWALL_OR_CONNECTION,
- 0, &ap);
- else
- valid_addr = !node_get_prim_orport(node, &ap);
+ fascist_firewall_choose_address_node(node, FIREWALL_OR_CONNECTION, 0, &ap);
+ else {
+ node_get_prim_orport(node, &ap);
+ }
+ valid_addr = tor_addr_port_is_valid_ap(&ap, 0);
if (valid_addr)
log_debug(LD_CIRC, "using %s for %s",
7apu2bq3rhoylwmucxizk54afw5jyda7pho4j5zdcqpwkufke7zdzwad.onion