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tor/src/or/hs_client.c

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/* Copyright (c) 2016-2017, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file hs_client.c
* \brief Implement next generation hidden service client functionality
**/
#define HS_CLIENT_PRIVATE
#include "or.h"
#include "hs_circuit.h"
#include "hs_ident.h"
#include "connection_edge.h"
#include "container.h"
#include "rendclient.h"
#include "hs_descriptor.h"
#include "hs_cache.h"
#include "hs_cell.h"
#include "hs_ident.h"
#include "config.h"
#include "directory.h"
#include "hs_client.h"
#include "router.h"
#include "routerset.h"
#include "circuitlist.h"
#include "circuituse.h"
#include "connection.h"
#include "nodelist.h"
#include "circpathbias.h"
#include "connection.h"
#include "hs_ntor.h"
#include "circuitbuild.h"
#include "networkstatus.h"
#include "reasons.h"
/* Return a human-readable string for the client fetch status code. */
static const char *
fetch_status_to_string(hs_client_fetch_status_t status)
{
switch (status) {
case HS_CLIENT_FETCH_ERROR:
return "Internal error";
case HS_CLIENT_FETCH_LAUNCHED:
return "Descriptor fetch launched";
case HS_CLIENT_FETCH_HAVE_DESC:
return "Already have descriptor";
case HS_CLIENT_FETCH_NO_HSDIRS:
return "No more HSDir available to query";
case HS_CLIENT_FETCH_NOT_ALLOWED:
return "Fetching descriptors is not allowed";
case HS_CLIENT_FETCH_MISSING_INFO:
return "Missing directory information";
case HS_CLIENT_FETCH_PENDING:
return "Pending descriptor fetch";
default:
return "(Unknown client fetch status code)";
}
}
/* Return true iff tor should close the SOCKS request(s) for the descriptor
* fetch that ended up with this given status code. */
static int
fetch_status_should_close_socks(hs_client_fetch_status_t status)
{
switch (status) {
case HS_CLIENT_FETCH_NO_HSDIRS:
/* No more HSDir to query, we can't complete the SOCKS request(s). */
case HS_CLIENT_FETCH_ERROR:
/* The fetch triggered an internal error. */
case HS_CLIENT_FETCH_NOT_ALLOWED:
/* Client is not allowed to fetch (FetchHidServDescriptors 0). */
goto close;
case HS_CLIENT_FETCH_MISSING_INFO:
case HS_CLIENT_FETCH_HAVE_DESC:
case HS_CLIENT_FETCH_PENDING:
case HS_CLIENT_FETCH_LAUNCHED:
/* The rest doesn't require tor to close the SOCKS request(s). */
goto no_close;
}
no_close:
return 0;
close:
return 1;
}
/* Cancel all descriptor fetches currently in progress. */
static void
cancel_descriptor_fetches(void)
{
smartlist_t *conns =
connection_list_by_type_state(CONN_TYPE_DIR, DIR_PURPOSE_FETCH_HSDESC);
SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
const hs_ident_dir_conn_t *ident = TO_DIR_CONN(conn)->hs_ident;
if (BUG(ident == NULL)) {
/* A directory connection fetching a service descriptor can't have an
* empty hidden service identifier. */
continue;
}
log_debug(LD_REND, "Marking for close a directory connection fetching "
"a hidden service descriptor for service %s.",
safe_str_client(ed25519_fmt(&ident->identity_pk)));
connection_mark_for_close(conn);
} SMARTLIST_FOREACH_END(conn);
/* No ownership of the objects in this list. */
smartlist_free(conns);
log_info(LD_REND, "Hidden service client descriptor fetches cancelled.");
}
/* Get all connections that are waiting on a circuit and flag them back to
* waiting for a hidden service descriptor for the given service key
* service_identity_pk. */
static void
flag_all_conn_wait_desc(const ed25519_public_key_t *service_identity_pk)
{
tor_assert(service_identity_pk);
smartlist_t *conns =
connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_CIRCUIT_WAIT);
SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
edge_connection_t *edge_conn;
if (BUG(!CONN_IS_EDGE(conn))) {
continue;
}
edge_conn = TO_EDGE_CONN(conn);
if (edge_conn->hs_ident &&
ed25519_pubkey_eq(&edge_conn->hs_ident->identity_pk,
service_identity_pk)) {
connection_ap_mark_as_non_pending_circuit(TO_ENTRY_CONN(conn));
conn->state = AP_CONN_STATE_RENDDESC_WAIT;
}
} SMARTLIST_FOREACH_END(conn);
smartlist_free(conns);
}
/* Remove tracked HSDir requests from our history for this hidden service
* identity public key. */
static void
purge_hid_serv_request(const ed25519_public_key_t *identity_pk)
{
char base64_blinded_pk[ED25519_BASE64_LEN + 1];
ed25519_public_key_t blinded_pk;
tor_assert(identity_pk);
/* Get blinded pubkey of hidden service. It is possible that we just moved
* to a new time period meaning that we won't be able to purge the request
* from the previous time period. That is fine because they will expire at
* some point and we don't care about those anymore. */
hs_build_blinded_pubkey(identity_pk, NULL, 0,
hs_get_time_period_num(0), &blinded_pk);
if (BUG(ed25519_public_to_base64(base64_blinded_pk, &blinded_pk) < 0)) {
return;
}
/* Purge last hidden service request from cache for this blinded key. */
hs_purge_hid_serv_from_last_hid_serv_requests(base64_blinded_pk);
}
/* Return true iff there is at least one pending directory descriptor request
* for the service identity_pk. */
static int
directory_request_is_pending(const ed25519_public_key_t *identity_pk)
{
int ret = 0;
smartlist_t *conns =
connection_list_by_type_purpose(CONN_TYPE_DIR, DIR_PURPOSE_FETCH_HSDESC);
SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
const hs_ident_dir_conn_t *ident = TO_DIR_CONN(conn)->hs_ident;
if (BUG(ident == NULL)) {
/* A directory connection fetching a service descriptor can't have an
* empty hidden service identifier. */
continue;
}
if (!ed25519_pubkey_eq(identity_pk, &ident->identity_pk)) {
continue;
}
ret = 1;
break;
} SMARTLIST_FOREACH_END(conn);
/* No ownership of the objects in this list. */
smartlist_free(conns);
return ret;
}
/* We failed to fetch a descriptor for the service with <b>identity_pk</b>
* because of <b>status</b>. Find all pending SOCKS connections for this
* service that are waiting on the descriptor and close them with
* <b>reason</b>. */
static void
close_all_socks_conns_waiting_for_desc(const ed25519_public_key_t *identity_pk,
hs_client_fetch_status_t status,
int reason)
{
unsigned int count = 0;
time_t now = approx_time();
smartlist_t *conns =
connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_RENDDESC_WAIT);
SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
entry_connection_t *entry_conn = TO_ENTRY_CONN(base_conn);
const edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(entry_conn);
/* Only consider the entry connections that matches the service for which
* we tried to get the descriptor */
if (!edge_conn->hs_ident ||
!ed25519_pubkey_eq(identity_pk,
&edge_conn->hs_ident->identity_pk)) {
continue;
}
assert_connection_ok(base_conn, now);
/* Unattach the entry connection which will close for the reason. */
connection_mark_unattached_ap(entry_conn, reason);
count++;
} SMARTLIST_FOREACH_END(base_conn);
if (count > 0) {
char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
hs_build_address(identity_pk, HS_VERSION_THREE, onion_address);
log_notice(LD_REND, "Closed %u streams for service %s.onion "
"for reason %s. Fetch status: %s.",
count, safe_str_client(onion_address),
stream_end_reason_to_string(reason),
fetch_status_to_string(status));
}
/* No ownership of the object(s) in this list. */
smartlist_free(conns);
}
/* Find all pending SOCKS connection waiting for a descriptor and retry them
* all. This is called when the directory information changed. */
static void
retry_all_socks_conn_waiting_for_desc(void)
{
smartlist_t *conns =
connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_RENDDESC_WAIT);
SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
hs_client_fetch_status_t status;
const edge_connection_t *edge_conn =
ENTRY_TO_EDGE_CONN(TO_ENTRY_CONN(base_conn));
/* Ignore non HS or non v3 connection. */
if (edge_conn->hs_ident == NULL) {
continue;
}
/* In this loop, we will possibly try to fetch a descriptor for the
* pending connections because we just got more directory information.
* However, the refetch process can cleanup all SOCKS request so the same
* service if an internal error happens. Thus, we can end up with closed
* connections in our list. */
if (base_conn->marked_for_close) {
continue;
}
/* XXX: There is an optimization we could do which is that for a service
* key, we could check if we can fetch and remember that decision. */
/* Order a refetch in case it works this time. */
status = hs_client_refetch_hsdesc(&edge_conn->hs_ident->identity_pk);
if (BUG(status == HS_CLIENT_FETCH_HAVE_DESC)) {
/* This case is unique because it can NOT happen in theory. Once we get
* a new descriptor, the HS client subsystem is notified immediately and
* the connections waiting for it are handled which means the state will
* change from renddesc wait state. Log this and continue to next
* connection. */
continue;
}
/* In the case of an error, either all SOCKS connections have been
* closed or we are still missing directory information. Leave the
* connection in renddesc wait state so when we get more info, we'll be
* able to try it again. */
} SMARTLIST_FOREACH_END(base_conn);
/* We don't have ownership of those objects. */
smartlist_free(conns);
}
/* A v3 HS circuit successfully connected to the hidden service. Update the
* stream state at <b>hs_conn_ident</b> appropriately. */
static void
note_connection_attempt_succeeded(const hs_ident_edge_conn_t *hs_conn_ident)
{
tor_assert(hs_conn_ident);
/* Remove from the hid serv cache all requests for that service so we can
* query the HSDir again later on for various reasons. */
purge_hid_serv_request(&hs_conn_ident->identity_pk);
/* The v2 subsystem cleans up the intro point time out flag at this stage.
* We don't try to do it here because we still need to keep intact the intro
* point state for future connections. Even though we are able to connect to
* the service, doesn't mean we should reset the timed out intro points.
*
* It is not possible to have successfully connected to an intro point
* present in our cache that was on error or timed out. Every entry in that
* cache have a 2 minutes lifetime so ultimately the intro point(s) state
* will be reset and thus possible to be retried. */
}
/* Given the pubkey of a hidden service in <b>onion_identity_pk</b>, fetch its
* descriptor by launching a dir connection to <b>hsdir</b>. Return a
* hs_client_fetch_status_t status code depending on how it went. */
static hs_client_fetch_status_t
directory_launch_v3_desc_fetch(const ed25519_public_key_t *onion_identity_pk,
const routerstatus_t *hsdir)
{
uint64_t current_time_period = hs_get_time_period_num(0);
ed25519_public_key_t blinded_pubkey;
char base64_blinded_pubkey[ED25519_BASE64_LEN + 1];
hs_ident_dir_conn_t hs_conn_dir_ident;
int retval;
tor_assert(hsdir);
tor_assert(onion_identity_pk);
/* Get blinded pubkey */
hs_build_blinded_pubkey(onion_identity_pk, NULL, 0,
current_time_period, &blinded_pubkey);
/* ...and base64 it. */
retval = ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey);
if (BUG(retval < 0)) {
return HS_CLIENT_FETCH_ERROR;
}
/* Copy onion pk to a dir_ident so that we attach it to the dir conn */
hs_ident_dir_conn_init(onion_identity_pk, &blinded_pubkey,
&hs_conn_dir_ident);
/* Setup directory request */
directory_request_t *req =
directory_request_new(DIR_PURPOSE_FETCH_HSDESC);
directory_request_set_routerstatus(req, hsdir);
directory_request_set_indirection(req, DIRIND_ANONYMOUS);
directory_request_set_resource(req, base64_blinded_pubkey);
directory_request_fetch_set_hs_ident(req, &hs_conn_dir_ident);
directory_initiate_request(req);
directory_request_free(req);
log_info(LD_REND, "Descriptor fetch request for service %s with blinded "
"key %s to directory %s",
safe_str_client(ed25519_fmt(onion_identity_pk)),
safe_str_client(base64_blinded_pubkey),
safe_str_client(routerstatus_describe(hsdir)));
/* Cleanup memory. */
memwipe(&blinded_pubkey, 0, sizeof(blinded_pubkey));
memwipe(base64_blinded_pubkey, 0, sizeof(base64_blinded_pubkey));
memwipe(&hs_conn_dir_ident, 0, sizeof(hs_conn_dir_ident));
return HS_CLIENT_FETCH_LAUNCHED;
}
/** Return the HSDir we should use to fetch the descriptor of the hidden
* service with identity key <b>onion_identity_pk</b>. */
STATIC routerstatus_t *
pick_hsdir_v3(const ed25519_public_key_t *onion_identity_pk)
{
int retval;
char base64_blinded_pubkey[ED25519_BASE64_LEN + 1];
uint64_t current_time_period = hs_get_time_period_num(0);
smartlist_t *responsible_hsdirs;
ed25519_public_key_t blinded_pubkey;
routerstatus_t *hsdir_rs = NULL;
tor_assert(onion_identity_pk);
responsible_hsdirs = smartlist_new();
/* Get blinded pubkey of hidden service */
hs_build_blinded_pubkey(onion_identity_pk, NULL, 0,
current_time_period, &blinded_pubkey);
/* ...and base64 it. */
retval = ed25519_public_to_base64(base64_blinded_pubkey, &blinded_pubkey);
if (BUG(retval < 0)) {
return NULL;
}
/* Get responsible hsdirs of service for this time period */
hs_get_responsible_hsdirs(&blinded_pubkey, current_time_period,
0, 1, responsible_hsdirs);
log_debug(LD_REND, "Found %d responsible HSDirs and about to pick one.",
smartlist_len(responsible_hsdirs));
/* Pick an HSDir from the responsible ones. The ownership of
* responsible_hsdirs is given to this function so no need to free it. */
hsdir_rs = hs_pick_hsdir(responsible_hsdirs, base64_blinded_pubkey);
return hsdir_rs;
}
/** Fetch a v3 descriptor using the given <b>onion_identity_pk</b>.
*
* On success, HS_CLIENT_FETCH_LAUNCHED is returned. Otherwise, an error from
* hs_client_fetch_status_t is returned. */
MOCK_IMPL(STATIC hs_client_fetch_status_t,
fetch_v3_desc, (const ed25519_public_key_t *onion_identity_pk))
{
routerstatus_t *hsdir_rs =NULL;
tor_assert(onion_identity_pk);
hsdir_rs = pick_hsdir_v3(onion_identity_pk);
if (!hsdir_rs) {
log_info(LD_REND, "Couldn't pick a v3 hsdir.");
return HS_CLIENT_FETCH_NO_HSDIRS;
}
return directory_launch_v3_desc_fetch(onion_identity_pk, hsdir_rs);
}
/* Make sure that the given v3 origin circuit circ is a valid correct
* introduction circuit. This will BUG() on any problems and hard assert if
* the anonymity of the circuit is not ok. Return 0 on success else -1 where
* the circuit should be mark for closed immediately. */
static int
intro_circ_is_ok(const origin_circuit_t *circ)
{
int ret = 0;
tor_assert(circ);
if (BUG(TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCING &&
TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT &&
TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACKED)) {
ret = -1;
}
if (BUG(circ->hs_ident == NULL)) {
ret = -1;
}
if (BUG(!hs_ident_intro_circ_is_valid(circ->hs_ident))) {
ret = -1;
}
/* This can stop the tor daemon but we want that since if we don't have
* anonymity on this circuit, something went really wrong. */
assert_circ_anonymity_ok(circ, get_options());
return ret;
}
/* Find a descriptor intro point object that matches the given ident in the
* given descriptor desc. Return NULL if not found. */
static const hs_desc_intro_point_t *
find_desc_intro_point_by_ident(const hs_ident_circuit_t *ident,
const hs_descriptor_t *desc)
{
const hs_desc_intro_point_t *intro_point = NULL;
tor_assert(ident);
tor_assert(desc);
SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
const hs_desc_intro_point_t *, ip) {
if (ed25519_pubkey_eq(&ident->intro_auth_pk,
&ip->auth_key_cert->signed_key)) {
intro_point = ip;
break;
}
} SMARTLIST_FOREACH_END(ip);
return intro_point;
}
/* Find a descriptor intro point object from the descriptor object desc that
* matches the given legacy identity digest in legacy_id. Return NULL if not
* found. */
static hs_desc_intro_point_t *
find_desc_intro_point_by_legacy_id(const char *legacy_id,
const hs_descriptor_t *desc)
{
hs_desc_intro_point_t *ret_ip = NULL;
tor_assert(legacy_id);
tor_assert(desc);
/* We will go over every intro point and try to find which one is linked to
* that circuit. Those lists are small so it's not that expensive. */
SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
hs_desc_intro_point_t *, ip) {
SMARTLIST_FOREACH_BEGIN(ip->link_specifiers,
const hs_desc_link_specifier_t *, lspec) {
/* Not all tor node have an ed25519 identity key so we still rely on the
* legacy identity digest. */
if (lspec->type != LS_LEGACY_ID) {
continue;
}
if (fast_memneq(legacy_id, lspec->u.legacy_id, DIGEST_LEN)) {
break;
}
/* Found it. */
ret_ip = ip;
goto end;
} SMARTLIST_FOREACH_END(lspec);
} SMARTLIST_FOREACH_END(ip);
end:
return ret_ip;
}
/* Send an INTRODUCE1 cell along the intro circuit and populate the rend
* circuit identifier with the needed key material for the e2e encryption.
* Return 0 on success, -1 if there is a transient error such that an action
* has been taken to recover and -2 if there is a permanent error indicating
* that both circuits were closed. */
static int
send_introduce1(origin_circuit_t *intro_circ,
origin_circuit_t *rend_circ)
{
int status;
char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
const ed25519_public_key_t *service_identity_pk = NULL;
const hs_desc_intro_point_t *ip;
tor_assert(rend_circ);
if (intro_circ_is_ok(intro_circ) < 0) {
goto perm_err;
}
service_identity_pk = &intro_circ->hs_ident->identity_pk;
/* For logging purposes. There will be a time where the hs_ident will have a
* version number but for now there is none because it's all v3. */
hs_build_address(service_identity_pk, HS_VERSION_THREE, onion_address);
log_info(LD_REND, "Sending INTRODUCE1 cell to service %s on circuit %u",
safe_str_client(onion_address), TO_CIRCUIT(intro_circ)->n_circ_id);
/* 1) Get descriptor from our cache. */
const hs_descriptor_t *desc =
hs_cache_lookup_as_client(service_identity_pk);
if (desc == NULL || !hs_client_any_intro_points_usable(service_identity_pk,
desc)) {
log_info(LD_REND, "Request to %s %s. Trying to fetch a new descriptor.",
safe_str_client(onion_address),
(desc) ? "didn't have usable intro points" :
"didn't have a descriptor");
hs_client_refetch_hsdesc(service_identity_pk);
/* We just triggered a refetch, make sure every connections are back
* waiting for that descriptor. */
flag_all_conn_wait_desc(service_identity_pk);
/* We just asked for a refetch so this is a transient error. */
goto tran_err;
}
/* We need to find which intro point in the descriptor we are connected to
* on intro_circ. */
ip = find_desc_intro_point_by_ident(intro_circ->hs_ident, desc);
if (BUG(ip == NULL)) {
/* If we can find a descriptor from this introduction circuit ident, we
* must have a valid intro point object. Permanent error. */
goto perm_err;
}
/* Send the INTRODUCE1 cell. */
if (hs_circ_send_introduce1(intro_circ, rend_circ, ip,
desc->subcredential) < 0) {
/* Unable to send the cell, the intro circuit has been marked for close so
* this is a permanent error. */
tor_assert_nonfatal(TO_CIRCUIT(intro_circ)->marked_for_close);
goto perm_err;
}
/* Cell has been sent successfully. Copy the introduction point
* authentication and encryption key in the rendezvous circuit identifier so
* we can compute the ntor keys when we receive the RENDEZVOUS2 cell. */
memcpy(&rend_circ->hs_ident->intro_enc_pk, &ip->enc_key,
sizeof(rend_circ->hs_ident->intro_enc_pk));
ed25519_pubkey_copy(&rend_circ->hs_ident->intro_auth_pk,
&intro_circ->hs_ident->intro_auth_pk);
/* Now, we wait for an ACK or NAK on this circuit. */
circuit_change_purpose(TO_CIRCUIT(intro_circ),
CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT);
/* Set timestamp_dirty, because circuit_expire_building expects it to
* specify when a circuit entered the _C_INTRODUCE_ACK_WAIT state. */
TO_CIRCUIT(intro_circ)->timestamp_dirty = time(NULL);
pathbias_count_use_attempt(intro_circ);
/* Success. */
status = 0;
goto end;
perm_err:
/* Permanent error: it is possible that the intro circuit was closed prior
* because we weren't able to send the cell. Make sure we don't double close
* it which would result in a warning. */
if (!TO_CIRCUIT(intro_circ)->marked_for_close) {
circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_INTERNAL);
}
circuit_mark_for_close(TO_CIRCUIT(rend_circ), END_CIRC_REASON_INTERNAL);
status = -2;
goto end;
tran_err:
status = -1;
end:
memwipe(onion_address, 0, sizeof(onion_address));
return status;
}
/* Using the introduction circuit circ, setup the authentication key of the
* intro point this circuit has extended to. */
static void
setup_intro_circ_auth_key(origin_circuit_t *circ)
{
const hs_descriptor_t *desc;
const hs_desc_intro_point_t *ip;
tor_assert(circ);
desc = hs_cache_lookup_as_client(&circ->hs_ident->identity_pk);
if (BUG(desc == NULL)) {
/* Opening intro circuit without the descriptor is no good... */
goto end;
}
/* We will go over every intro point and try to find which one is linked to
* that circuit. Those lists are small so it's not that expensive. */
ip = find_desc_intro_point_by_legacy_id(
circ->build_state->chosen_exit->identity_digest, desc);
if (ip) {
/* We got it, copy its authentication key to the identifier. */
ed25519_pubkey_copy(&circ->hs_ident->intro_auth_pk,
&ip->auth_key_cert->signed_key);
goto end;
}
/* Reaching this point means we didn't find any intro point for this circuit
* which is not suppose to happen. */
tor_assert_nonfatal_unreached();
end:
return;
}
/* Called when an introduction circuit has opened. */
static void
client_intro_circ_has_opened(origin_circuit_t *circ)
{
tor_assert(circ);
tor_assert(TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_C_INTRODUCING);
log_info(LD_REND, "Introduction circuit %u has opened. Attaching streams.",
(unsigned int) TO_CIRCUIT(circ)->n_circ_id);
/* This is an introduction circuit so we'll attach the correct
* authentication key to the circuit identifier so it can be identified
* properly later on. */
setup_intro_circ_auth_key(circ);
connection_ap_attach_pending(1);
}
/* Called when a rendezvous circuit has opened. */
static void
client_rendezvous_circ_has_opened(origin_circuit_t *circ)
{
tor_assert(circ);
tor_assert(TO_CIRCUIT(circ)->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND);
const extend_info_t *rp_ei = circ->build_state->chosen_exit;
/* Check that we didn't accidentally choose a node that does not understand
* the v3 rendezvous protocol */
if (rp_ei) {
const node_t *rp_node = node_get_by_id(rp_ei->identity_digest);
if (rp_node) {
if (BUG(!node_supports_v3_rendezvous_point(rp_node))) {
return;
}
}
}
log_info(LD_REND, "Rendezvous circuit has opened to %s.",
safe_str_client(extend_info_describe(rp_ei)));
/* Ignore returned value, nothing we can really do. On failure, the circuit
* will be marked for close. */
hs_circ_send_establish_rendezvous(circ);
/* Register rend circuit in circuitmap if it's still alive. */
if (!TO_CIRCUIT(circ)->marked_for_close) {
hs_circuitmap_register_rend_circ_client_side(circ,
circ->hs_ident->rendezvous_cookie);
}
}
/* This is an helper function that convert a descriptor intro point object ip
* to a newly allocated extend_info_t object fully initialized. Return NULL if
* we can't convert it for which chances are that we are missing or malformed
* link specifiers. */
STATIC extend_info_t *
desc_intro_point_to_extend_info(const hs_desc_intro_point_t *ip)
{
extend_info_t *ei;
smartlist_t *lspecs = smartlist_new();
tor_assert(ip);
/* We first encode the descriptor link specifiers into the binary
* representation which is a trunnel object. */
SMARTLIST_FOREACH_BEGIN(ip->link_specifiers,
const hs_desc_link_specifier_t *, desc_lspec) {
link_specifier_t *lspec = hs_desc_lspec_to_trunnel(desc_lspec);
smartlist_add(lspecs, lspec);
} SMARTLIST_FOREACH_END(desc_lspec);
/* Explicitely put the direct connection option to 0 because this is client
* side and there is no such thing as a non anonymous client. */
ei = hs_get_extend_info_from_lspecs(lspecs, &ip->onion_key, 0);
SMARTLIST_FOREACH(lspecs, link_specifier_t *, ls, link_specifier_free(ls));
smartlist_free(lspecs);
return ei;
}
/* Return true iff the intro point ip for the service service_pk is usable.
* This function checks if the intro point is in the client intro state cache
* and checks at the failures. It is considered usable if:
* - No error happened (INTRO_POINT_FAILURE_GENERIC)
* - It is not flagged as timed out (INTRO_POINT_FAILURE_TIMEOUT)
* - The unreachable count is lower than
* MAX_INTRO_POINT_REACHABILITY_FAILURES (INTRO_POINT_FAILURE_UNREACHABLE)
*/
static int
intro_point_is_usable(const ed25519_public_key_t *service_pk,
const hs_desc_intro_point_t *ip)
{
const hs_cache_intro_state_t *state;
tor_assert(service_pk);
tor_assert(ip);
state = hs_cache_client_intro_state_find(service_pk,
&ip->auth_key_cert->signed_key);
if (state == NULL) {
/* This means we've never encountered any problem thus usable. */
goto usable;
}
if (state->error) {
log_info(LD_REND, "Intro point with auth key %s had an error. Not usable",
safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)));
goto not_usable;
}
if (state->timed_out) {
log_info(LD_REND, "Intro point with auth key %s timed out. Not usable",
safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)));
goto not_usable;
}
if (state->unreachable_count >= MAX_INTRO_POINT_REACHABILITY_FAILURES) {
log_info(LD_REND, "Intro point with auth key %s unreachable. Not usable",
safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)));
goto not_usable;
}
usable:
return 1;
not_usable:
return 0;
}
/* Using a descriptor desc, return a newly allocated extend_info_t object of a
* randomly picked introduction point from its list. Return NULL if none are
* usable. */
STATIC extend_info_t *
client_get_random_intro(const ed25519_public_key_t *service_pk)
{
extend_info_t *ei = NULL, *ei_excluded = NULL;
smartlist_t *usable_ips = NULL;
const hs_descriptor_t *desc;
const hs_desc_encrypted_data_t *enc_data;
const or_options_t *options = get_options();
/* Calculate the onion address for logging purposes */
char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
tor_assert(service_pk);
desc = hs_cache_lookup_as_client(service_pk);
/* Assume the service is v3 if the descriptor is missing. This is ok,
* because we only use the address in log messages */
hs_build_address(service_pk,
desc ? desc->plaintext_data.version : HS_VERSION_THREE,
onion_address);
if (desc == NULL || !hs_client_any_intro_points_usable(service_pk,
desc)) {
log_info(LD_REND, "Unable to randomly select an introduction point "
"for service %s because descriptor %s. We can't connect.",
safe_str_client(onion_address),
(desc) ? "doesn't have any usable intro points"
: "is missing (assuming v3 onion address)");
goto end;
}
enc_data = &desc->encrypted_data;
usable_ips = smartlist_new();
smartlist_add_all(usable_ips, enc_data->intro_points);
while (smartlist_len(usable_ips) != 0) {
int idx;
const hs_desc_intro_point_t *ip;
/* Pick a random intro point and immediately remove it from the usable
* list so we don't pick it again if we have to iterate more. */
idx = crypto_rand_int(smartlist_len(usable_ips));
ip = smartlist_get(usable_ips, idx);
smartlist_del(usable_ips, idx);
/* We need to make sure we have a usable intro points which is in a good
* state in our cache. */
if (!intro_point_is_usable(service_pk, ip)) {
continue;
}
/* Generate an extend info object from the intro point object. */
ei = desc_intro_point_to_extend_info(ip);
if (ei == NULL) {
/* We can get here for instance if the intro point is a private address
* and we aren't allowed to extend to those. */
log_info(LD_REND, "Unable to select introduction point with auth key %s "
"for service %s, because we could not extend to it.",
safe_str_client(ed25519_fmt(&ip->auth_key_cert->signed_key)),
safe_str_client(onion_address));
continue;
}
/* Test the pick against ExcludeNodes. */
if (routerset_contains_extendinfo(options->ExcludeNodes, ei)) {
/* If this pick is in the ExcludeNodes list, we keep its reference so if
* we ever end up not being able to pick anything else and StrictNodes is
* unset, we'll use it. */
if (ei_excluded) {
/* If something was already here free it. After the loop is gone we
* will examine the last excluded intro point, and that's fine since
* that's random anyway */
extend_info_free(ei_excluded);
}
ei_excluded = ei;
continue;
}
/* Good pick! Let's go with this. */
goto end;
}
/* Reaching this point means a couple of things. Either we can't use any of
* the intro point listed because the IP address can't be extended to or it
* is listed in the ExcludeNodes list. In the later case, if StrictNodes is
* set, we are forced to not use anything. */
ei = ei_excluded;
if (options->StrictNodes) {
log_warn(LD_REND, "Every introduction point for service %s is in the "
"ExcludeNodes set and StrictNodes is set. We can't connect.",
safe_str_client(onion_address));
extend_info_free(ei);
ei = NULL;
} else {
log_fn(LOG_PROTOCOL_WARN, LD_REND, "Every introduction point for service "
"%s is unusable or we can't extend to it. We can't connect.",
safe_str_client(onion_address));
}
end:
smartlist_free(usable_ips);
memwipe(onion_address, 0, sizeof(onion_address));
return ei;
}
/* For this introduction circuit, we'll look at if we have any usable
* introduction point left for this service. If so, we'll use the circuit to
* re-extend to a new intro point. Else, we'll close the circuit and its
* corresponding rendezvous circuit. Return 0 if we are re-extending else -1
* if we are closing the circuits.
*
* This is called when getting an INTRODUCE_ACK cell with a NACK. */
static int
close_or_reextend_intro_circ(origin_circuit_t *intro_circ)
{
int ret = -1;
const hs_descriptor_t *desc;
origin_circuit_t *rend_circ;
tor_assert(intro_circ);
desc = hs_cache_lookup_as_client(&intro_circ->hs_ident->identity_pk);
if (BUG(desc == NULL)) {
/* We can't continue without a descriptor. */
goto close;
}
/* We still have the descriptor, great! Let's try to see if we can
* re-extend by looking up if there are any usable intro points. */
if (!hs_client_any_intro_points_usable(&intro_circ->hs_ident->identity_pk,
desc)) {
goto close;
}
/* Try to re-extend now. */
if (hs_client_reextend_intro_circuit(intro_circ) < 0) {
goto close;
}
/* Success on re-extending. Don't return an error. */
ret = 0;
goto end;
close:
/* Change the intro circuit purpose before so we don't report an intro point
* failure again triggering an extra descriptor fetch. The circuit can
* already be closed on failure to re-extend. */
if (!TO_CIRCUIT(intro_circ)->marked_for_close) {
circuit_change_purpose(TO_CIRCUIT(intro_circ),
CIRCUIT_PURPOSE_C_INTRODUCE_ACKED);
circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_FINISHED);
}
/* Close the related rendezvous circuit. */
rend_circ = hs_circuitmap_get_rend_circ_client_side(
intro_circ->hs_ident->rendezvous_cookie);
/* The rendezvous circuit might have collapsed while the INTRODUCE_ACK was
* inflight so we can't expect one every time. */
if (rend_circ) {
circuit_mark_for_close(TO_CIRCUIT(rend_circ), END_CIRC_REASON_FINISHED);
}
end:
return ret;
}
/* Called when we get an INTRODUCE_ACK success status code. Do the appropriate
* actions for the rendezvous point and finally close intro_circ. */
static void
handle_introduce_ack_success(origin_circuit_t *intro_circ)
{
origin_circuit_t *rend_circ = NULL;
tor_assert(intro_circ);
log_info(LD_REND, "Received INTRODUCE_ACK ack! Informing rendezvous");
/* Get the rendezvous circuit for this rendezvous cookie. */
uint8_t *rendezvous_cookie = intro_circ->hs_ident->rendezvous_cookie;
rend_circ = hs_circuitmap_get_rend_circ_client_side(rendezvous_cookie);
if (rend_circ == NULL) {
log_warn(LD_REND, "Can't find any rendezvous circuit. Stopping");
goto end;
}
assert_circ_anonymity_ok(rend_circ, get_options());
/* It is possible to get a RENDEZVOUS2 cell before the INTRODUCE_ACK which
* means that the circuit will be joined and already transmitting data. In
* that case, simply skip the purpose change and close the intro circuit
* like it should be. */
if (TO_CIRCUIT(rend_circ)->purpose == CIRCUIT_PURPOSE_C_REND_JOINED) {
goto end;
}
circuit_change_purpose(TO_CIRCUIT(rend_circ),
CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED);
/* Set timestamp_dirty, because circuit_expire_building expects it to
* specify when a circuit entered the
* CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED state. */
TO_CIRCUIT(rend_circ)->timestamp_dirty = time(NULL);
end:
/* We don't need the intro circuit anymore. It did what it had to do! */
circuit_change_purpose(TO_CIRCUIT(intro_circ),
CIRCUIT_PURPOSE_C_INTRODUCE_ACKED);
circuit_mark_for_close(TO_CIRCUIT(intro_circ), END_CIRC_REASON_FINISHED);
/* XXX: Close pending intro circuits we might have in parallel. */
return;
}
/* Called when we get an INTRODUCE_ACK failure status code. Depending on our
* failure cache status, either close the circuit or re-extend to a new
* introduction point. */
static void
handle_introduce_ack_bad(origin_circuit_t *circ, int status)
{
tor_assert(circ);
log_info(LD_REND, "Received INTRODUCE_ACK nack by %s. Reason: %u",
safe_str_client(extend_info_describe(circ->build_state->chosen_exit)),
status);
/* It's a NAK. The introduction point didn't relay our request. */
circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_INTRODUCING);
/* Note down this failure in the intro point failure cache. Depending on how
* many times we've tried this intro point, close it or reextend. */
hs_cache_client_intro_state_note(&circ->hs_ident->identity_pk,
&circ->hs_ident->intro_auth_pk,
INTRO_POINT_FAILURE_GENERIC);
}
/* Called when we get an INTRODUCE_ACK on the intro circuit circ. The encoded
* cell is in payload of length payload_len. Return 0 on success else a
* negative value. The circuit is either close or reuse to re-extend to a new
* introduction point. */
static int
handle_introduce_ack(origin_circuit_t *circ, const uint8_t *payload,
size_t payload_len)
{
int status, ret = -1;
tor_assert(circ);
tor_assert(circ->build_state);
tor_assert(circ->build_state->chosen_exit);
assert_circ_anonymity_ok(circ, get_options());
tor_assert(payload);
status = hs_cell_parse_introduce_ack(payload, payload_len);
switch (status) {
case HS_CELL_INTRO_ACK_SUCCESS:
ret = 0;
handle_introduce_ack_success(circ);
goto end;
case HS_CELL_INTRO_ACK_FAILURE:
case HS_CELL_INTRO_ACK_BADFMT:
case HS_CELL_INTRO_ACK_NORELAY:
handle_introduce_ack_bad(circ, status);
/* We are going to see if we have to close the circuits (IP and RP) or we
* can re-extend to a new intro point. */
ret = close_or_reextend_intro_circ(circ);
break;
default:
log_info(LD_PROTOCOL, "Unknown INTRODUCE_ACK status code %u from %s",
status,
safe_str_client(extend_info_describe(circ->build_state->chosen_exit)));
break;
}
end:
return ret;
}
/* Called when we get a RENDEZVOUS2 cell on the rendezvous circuit circ. The
* encoded cell is in payload of length payload_len. Return 0 on success or a
* negative value on error. On error, the circuit is marked for close. */
STATIC int
handle_rendezvous2(origin_circuit_t *circ, const uint8_t *payload,
size_t payload_len)
{
int ret = -1;
curve25519_public_key_t server_pk;
uint8_t auth_mac[DIGEST256_LEN] = {0};
uint8_t handshake_info[CURVE25519_PUBKEY_LEN + sizeof(auth_mac)] = {0};
hs_ntor_rend_cell_keys_t keys;
const hs_ident_circuit_t *ident;
tor_assert(circ);
tor_assert(payload);
/* Make things easier. */
ident = circ->hs_ident;
tor_assert(ident);
if (hs_cell_parse_rendezvous2(payload, payload_len, handshake_info,
sizeof(handshake_info)) < 0) {
goto err;
}
/* Get from the handshake info the SERVER_PK and AUTH_MAC. */
memcpy(&server_pk, handshake_info, CURVE25519_PUBKEY_LEN);
memcpy(auth_mac, handshake_info + CURVE25519_PUBKEY_LEN, sizeof(auth_mac));
/* Generate the handshake info. */
if (hs_ntor_client_get_rendezvous1_keys(&ident->intro_auth_pk,
&ident->rendezvous_client_kp,
&ident->intro_enc_pk, &server_pk,
&keys) < 0) {
log_info(LD_REND, "Unable to compute the rendezvous keys.");
goto err;
}
/* Critical check, make sure that the MAC matches what we got with what we
* computed just above. */
if (!hs_ntor_client_rendezvous2_mac_is_good(&keys, auth_mac)) {
log_info(LD_REND, "Invalid MAC in RENDEZVOUS2. Rejecting cell.");
goto err;
}
/* Setup the e2e encryption on the circuit and finalize its state. */
if (hs_circuit_setup_e2e_rend_circ(circ, keys.ntor_key_seed,
sizeof(keys.ntor_key_seed), 0) < 0) {
log_info(LD_REND, "Unable to setup the e2e encryption.");
goto err;
}
/* Success. Hidden service connection finalized! */
ret = 0;
goto end;
err:
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
end:
memwipe(&keys, 0, sizeof(keys));
return ret;
}
/* Return true iff the client can fetch a descriptor for this service public
* identity key and status_out if not NULL is untouched. If the client can
* _not_ fetch the descriptor and if status_out is not NULL, it is set with
* the fetch status code. */
static unsigned int
can_client_refetch_desc(const ed25519_public_key_t *identity_pk,
hs_client_fetch_status_t *status_out)
{
hs_client_fetch_status_t status;
tor_assert(identity_pk);
/* Are we configured to fetch descriptors? */
if (!get_options()->FetchHidServDescriptors) {
log_warn(LD_REND, "We received an onion address for a hidden service "
"descriptor but we are configured to not fetch.");
status = HS_CLIENT_FETCH_NOT_ALLOWED;
goto cannot;
}
/* Without a live consensus we can't do any client actions. It is needed to
* compute the hashring for a service. */
if (!networkstatus_get_live_consensus(approx_time())) {
log_info(LD_REND, "Can't fetch descriptor for service %s because we "
"are missing a live consensus. Stalling connection.",
safe_str_client(ed25519_fmt(identity_pk)));
status = HS_CLIENT_FETCH_MISSING_INFO;
goto cannot;
}
if (!router_have_minimum_dir_info()) {
log_info(LD_REND, "Can't fetch descriptor for service %s because we "
"dont have enough descriptors. Stalling connection.",
safe_str_client(ed25519_fmt(identity_pk)));
status = HS_CLIENT_FETCH_MISSING_INFO;
goto cannot;
}
/* Check if fetching a desc for this HS is useful to us right now */
{
const hs_descriptor_t *cached_desc = NULL;
cached_desc = hs_cache_lookup_as_client(identity_pk);
if (cached_desc && hs_client_any_intro_points_usable(identity_pk,
cached_desc)) {
log_info(LD_GENERAL, "We would fetch a v3 hidden service descriptor "
"but we already have a usable descriptor.");
status = HS_CLIENT_FETCH_HAVE_DESC;
goto cannot;
}
}
/* Don't try to refetch while we have a pending request for it. */
if (directory_request_is_pending(identity_pk)) {
log_info(LD_REND, "Already a pending directory request. Waiting on it.");
status = HS_CLIENT_FETCH_PENDING;
goto cannot;
}
/* Yes, client can fetch! */
return 1;
cannot:
if (status_out) {
*status_out = status;
}
return 0;
}
/* ========== */
/* Public API */
/* ========== */
/** A circuit just finished connecting to a hidden service that the stream
* <b>conn</b> has been waiting for. Let the HS subsystem know about this. */
void
hs_client_note_connection_attempt_succeeded(const edge_connection_t *conn)
{
tor_assert(connection_edge_is_rendezvous_stream(conn));
if (BUG(conn->rend_data && conn->hs_ident)) {
log_warn(LD_BUG, "Stream had both rend_data and hs_ident..."
"Prioritizing hs_ident");
}
if (conn->hs_ident) { /* It's v3: pass it to the prop224 handler */
note_connection_attempt_succeeded(conn->hs_ident);
return;
} else if (conn->rend_data) { /* It's v2: pass it to the legacy handler */
rend_client_note_connection_attempt_ended(conn->rend_data);
return;
}
}
/* With the given encoded descriptor in desc_str and the service key in
* service_identity_pk, decode the descriptor and set the desc pointer with a
* newly allocated descriptor object.
*
* Return 0 on success else a negative value and desc is set to NULL. */
int
hs_client_decode_descriptor(const char *desc_str,
const ed25519_public_key_t *service_identity_pk,
hs_descriptor_t **desc)
{
int ret;
uint8_t subcredential[DIGEST256_LEN];
ed25519_public_key_t blinded_pubkey;
tor_assert(desc_str);
tor_assert(service_identity_pk);
tor_assert(desc);
/* Create subcredential for this HS so that we can decrypt */
{
uint64_t current_time_period = hs_get_time_period_num(0);
hs_build_blinded_pubkey(service_identity_pk, NULL, 0, current_time_period,
&blinded_pubkey);
hs_get_subcredential(service_identity_pk, &blinded_pubkey, subcredential);
}
/* Parse descriptor */
ret = hs_desc_decode_descriptor(desc_str, subcredential, desc);
memwipe(subcredential, 0, sizeof(subcredential));
if (ret < 0) {
log_warn(LD_GENERAL, "Could not parse received descriptor as client.");
if (get_options()->SafeLogging_ == SAFELOG_SCRUB_NONE) {
log_warn(LD_GENERAL, "%s", escaped(desc_str));
}
goto err;
}
/* Make sure the descriptor signing key cross certifies with the computed
* blinded key. Without this validation, anyone knowing the subcredential
* and onion address can forge a descriptor. */
tor_cert_t *cert = (*desc)->plaintext_data.signing_key_cert;
if (tor_cert_checksig(cert,
&blinded_pubkey, approx_time()) < 0) {
log_warn(LD_GENERAL, "Descriptor signing key certificate signature "
"doesn't validate with computed blinded key: %s",
tor_cert_describe_signature_status(cert));
goto err;
}
return 0;
err:
return -1;
}
/* Return true iff there are at least one usable intro point in the service
* descriptor desc. */
int
hs_client_any_intro_points_usable(const ed25519_public_key_t *service_pk,
const hs_descriptor_t *desc)
{
tor_assert(service_pk);
tor_assert(desc);
SMARTLIST_FOREACH_BEGIN(desc->encrypted_data.intro_points,
const hs_desc_intro_point_t *, ip) {
if (intro_point_is_usable(service_pk, ip)) {
goto usable;
}
} SMARTLIST_FOREACH_END(ip);
return 0;
usable:
return 1;
}
/** Launch a connection to a hidden service directory to fetch a hidden
* service descriptor using <b>identity_pk</b> to get the necessary keys.
*
* A hs_client_fetch_status_t code is returned. */
int
hs_client_refetch_hsdesc(const ed25519_public_key_t *identity_pk)
{
hs_client_fetch_status_t status;
tor_assert(identity_pk);
if (!can_client_refetch_desc(identity_pk, &status)) {
return status;
}
/* Try to fetch the desc and if we encounter an unrecoverable error, mark
* the desc as unavailable for now. */
status = fetch_v3_desc(identity_pk);
if (fetch_status_should_close_socks(status)) {
close_all_socks_conns_waiting_for_desc(identity_pk, status,
END_STREAM_REASON_RESOLVEFAILED);
/* Remove HSDir fetch attempts so that we can retry later if the user
* wants us to regardless of if we closed any connections. */
purge_hid_serv_request(identity_pk);
}
return status;
}
/* This is called when we are trying to attach an AP connection to these
* hidden service circuits from connection_ap_handshake_attach_circuit().
* Return 0 on success, -1 for a transient error that is actions were
* triggered to recover or -2 for a permenent error where both circuits will
* marked for close.
*
* The following supports every hidden service version. */
int
hs_client_send_introduce1(origin_circuit_t *intro_circ,
origin_circuit_t *rend_circ)
{
return (intro_circ->hs_ident) ? send_introduce1(intro_circ, rend_circ) :
rend_client_send_introduction(intro_circ,
rend_circ);
}
/* Called when the client circuit circ has been established. It can be either
* an introduction or rendezvous circuit. This function handles all hidden
* service versions. */
void
hs_client_circuit_has_opened(origin_circuit_t *circ)
{
tor_assert(circ);
/* Handle both version. v2 uses rend_data and v3 uses the hs circuit
* identifier hs_ident. Can't be both. */
switch (TO_CIRCUIT(circ)->purpose) {
case CIRCUIT_PURPOSE_C_INTRODUCING:
if (circ->hs_ident) {
client_intro_circ_has_opened(circ);
} else {
rend_client_introcirc_has_opened(circ);
}
break;
case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
if (circ->hs_ident) {
client_rendezvous_circ_has_opened(circ);
} else {
rend_client_rendcirc_has_opened(circ);
}
break;
default:
tor_assert_nonfatal_unreached();
}
}
/* Called when we receive a RENDEZVOUS_ESTABLISHED cell. Change the state of
* the circuit to CIRCUIT_PURPOSE_C_REND_READY. Return 0 on success else a
* negative value and the circuit marked for close. */
int
hs_client_receive_rendezvous_acked(origin_circuit_t *circ,
const uint8_t *payload, size_t payload_len)
{
tor_assert(circ);
tor_assert(payload);
(void) payload_len;
if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND) {
log_warn(LD_PROTOCOL, "Got a RENDEZVOUS_ESTABLISHED but we were not "
"expecting one. Closing circuit.");
goto err;
}
log_info(LD_REND, "Received an RENDEZVOUS_ESTABLISHED. This circuit is "
"now ready for rendezvous.");
circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_REND_READY);
/* Set timestamp_dirty, because circuit_expire_building expects it to
* specify when a circuit entered the _C_REND_READY state. */
TO_CIRCUIT(circ)->timestamp_dirty = time(NULL);
/* From a path bias point of view, this circuit is now successfully used.
* Waiting any longer opens us up to attacks from malicious hidden services.
* They could induce the client to attempt to connect to their hidden
* service and never reply to the client's rend requests */
pathbias_mark_use_success(circ);
/* If we already have the introduction circuit built, make sure we send
* the INTRODUCE cell _now_ */
connection_ap_attach_pending(1);
return 0;
err:
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
return -1;
}
/* This is called when a descriptor has arrived following a fetch request and
* has been stored in the client cache. Every entry connection that matches
* the service identity key in the ident will get attached to the hidden
* service circuit. */
void
hs_client_desc_has_arrived(const hs_ident_dir_conn_t *ident)
{
time_t now = time(NULL);
smartlist_t *conns = NULL;
tor_assert(ident);
conns = connection_list_by_type_state(CONN_TYPE_AP,
AP_CONN_STATE_RENDDESC_WAIT);
SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
const hs_descriptor_t *desc;
entry_connection_t *entry_conn = TO_ENTRY_CONN(base_conn);
const edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(entry_conn);
/* Only consider the entry connections that matches the service for which
* we just fetched its descriptor. */
if (!edge_conn->hs_ident ||
!ed25519_pubkey_eq(&ident->identity_pk,
&edge_conn->hs_ident->identity_pk)) {
continue;
}
assert_connection_ok(base_conn, now);
/* We were just called because we stored the descriptor for this service
* so not finding a descriptor means we have a bigger problem. */
desc = hs_cache_lookup_as_client(&ident->identity_pk);
if (BUG(desc == NULL)) {
goto end;
}
if (!hs_client_any_intro_points_usable(&ident->identity_pk, desc)) {
log_info(LD_REND, "Hidden service descriptor is unusable. "
"Closing streams.");
connection_mark_unattached_ap(entry_conn,
END_STREAM_REASON_RESOLVEFAILED);
/* We are unable to use the descriptor so remove the directory request
* from the cache so the next connection can try again. */
note_connection_attempt_succeeded(edge_conn->hs_ident);
goto end;
}
log_info(LD_REND, "Descriptor has arrived. Launching circuits.");
/* Because the connection can now proceed to opening circuit and
* ultimately connect to the service, reset those timestamp so the
* connection is considered "fresh" and can continue without being closed
* too early. */
base_conn->timestamp_created = now;
base_conn->timestamp_lastread = now;
base_conn->timestamp_lastwritten = now;
/* Change connection's state into waiting for a circuit. */
base_conn->state = AP_CONN_STATE_CIRCUIT_WAIT;
connection_ap_mark_as_pending_circuit(entry_conn);
} SMARTLIST_FOREACH_END(base_conn);
end:
/* We don't have ownership of the objects in this list. */
smartlist_free(conns);
}
/* Return a newly allocated extend_info_t for a randomly chosen introduction
* point for the given edge connection identifier ident. Return NULL if we
* can't pick any usable introduction points. */
extend_info_t *
hs_client_get_random_intro_from_edge(const edge_connection_t *edge_conn)
{
tor_assert(edge_conn);
return (edge_conn->hs_ident) ?
client_get_random_intro(&edge_conn->hs_ident->identity_pk) :
rend_client_get_random_intro(edge_conn->rend_data);
}
/* Called when get an INTRODUCE_ACK cell on the introduction circuit circ.
* Return 0 on success else a negative value is returned. The circuit will be
* closed or reuse to extend again to another intro point. */
int
hs_client_receive_introduce_ack(origin_circuit_t *circ,
const uint8_t *payload, size_t payload_len)
{
int ret = -1;
tor_assert(circ);
tor_assert(payload);
if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) {
log_warn(LD_PROTOCOL, "Unexpected INTRODUCE_ACK on circuit %u.",
(unsigned int) TO_CIRCUIT(circ)->n_circ_id);
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
goto end;
}
ret = (circ->hs_ident) ? handle_introduce_ack(circ, payload, payload_len) :
rend_client_introduction_acked(circ, payload,
payload_len);
/* For path bias: This circuit was used successfully. NACK or ACK counts. */
pathbias_mark_use_success(circ);
end:
return ret;
}
/* Called when get a RENDEZVOUS2 cell on the rendezvous circuit circ. Return
* 0 on success else a negative value is returned. The circuit will be closed
* on error. */
int
hs_client_receive_rendezvous2(origin_circuit_t *circ,
const uint8_t *payload, size_t payload_len)
{
int ret = -1;
tor_assert(circ);
tor_assert(payload);
/* Circuit can possibly be in both state because we could receive a
* RENDEZVOUS2 cell before the INTRODUCE_ACK has been received. */
if (TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_REND_READY &&
TO_CIRCUIT(circ)->purpose != CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) {
log_warn(LD_PROTOCOL, "Unexpected RENDEZVOUS2 cell on circuit %u. "
"Closing circuit.",
(unsigned int) TO_CIRCUIT(circ)->n_circ_id);
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
goto end;
}
log_info(LD_REND, "Got RENDEZVOUS2 cell from hidden service on circuit %u.",
TO_CIRCUIT(circ)->n_circ_id);
ret = (circ->hs_ident) ? handle_rendezvous2(circ, payload, payload_len) :
rend_client_receive_rendezvous(circ, payload,
payload_len);
end:
return ret;
}
/* Extend the introduction circuit circ to another valid introduction point
* for the hidden service it is trying to connect to, or mark it and launch a
* new circuit if we can't extend it. Return 0 on success or possible
* success. Return -1 and mark the introduction circuit for close on permanent
* failure.
*
* On failure, the caller is responsible for marking the associated rendezvous
* circuit for close. */
int
hs_client_reextend_intro_circuit(origin_circuit_t *circ)
{
int ret = -1;
extend_info_t *ei;
tor_assert(circ);
ei = (circ->hs_ident) ?
client_get_random_intro(&circ->hs_ident->identity_pk) :
rend_client_get_random_intro(circ->rend_data);
if (ei == NULL) {
log_warn(LD_REND, "No usable introduction points left. Closing.");
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL);
goto end;
}
if (circ->remaining_relay_early_cells) {
log_info(LD_REND, "Re-extending circ %u, this time to %s.",
(unsigned int) TO_CIRCUIT(circ)->n_circ_id,
safe_str_client(extend_info_describe(ei)));
ret = circuit_extend_to_new_exit(circ, ei);
if (ret == 0) {
/* We were able to extend so update the timestamp so we avoid expiring
* this circuit too early. The intro circuit is short live so the
* linkability issue is minimized, we just need the circuit to hold a
* bit longer so we can introduce. */
TO_CIRCUIT(circ)->timestamp_dirty = time(NULL);
}
} else {
log_info(LD_REND, "Closing intro circ %u (out of RELAY_EARLY cells).",
(unsigned int) TO_CIRCUIT(circ)->n_circ_id);
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED);
/* connection_ap_handshake_attach_circuit will launch a new intro circ. */
ret = 0;
}
end:
extend_info_free(ei);
return ret;
}
/* Release all the storage held by the client subsystem. */
void
hs_client_free_all(void)
{
/* Purge the hidden service request cache. */
hs_purge_last_hid_serv_requests();
}
/* Purge all potentially remotely-detectable state held in the hidden
* service client code. Called on SIGNAL NEWNYM. */
void
hs_client_purge_state(void)
{
/* v2 subsystem. */
rend_client_purge_state();
/* Cancel all descriptor fetches. Do this first so once done we are sure
* that our descriptor cache won't modified. */
cancel_descriptor_fetches();
/* Purge the introduction point state cache. */
hs_cache_client_intro_state_purge();
/* Purge the descriptor cache. */
hs_cache_purge_as_client();
/* Purge the last hidden service request cache. */
hs_purge_last_hid_serv_requests();
log_info(LD_REND, "Hidden service client state has been purged.");
}
/* Called when our directory information has changed. */
void
hs_client_dir_info_changed(void)
{
/* We have possibly reached the minimum directory information or new
* consensus so retry all pending SOCKS connection in
* AP_CONN_STATE_RENDDESC_WAIT state in order to fetch the descriptor. */
retry_all_socks_conn_waiting_for_desc();
}
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