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tor/src/or/rendclient.c
Nick Mathewson 9f0cb5af15 Merge branch 'feature-17178-v7-squashed-v2'
2016-09-13 10:20:08 -04:00

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/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2016, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file rendclient.c
* \brief Client code to access location-hidden services.
**/
#include "or.h"
#include "circpathbias.h"
#include "circuitbuild.h"
#include "circuitlist.h"
#include "circuituse.h"
#include "config.h"
#include "connection.h"
#include "connection_edge.h"
#include "directory.h"
#include "main.h"
#include "networkstatus.h"
#include "nodelist.h"
#include "relay.h"
#include "rendclient.h"
#include "rendcommon.h"
#include "rephist.h"
#include "router.h"
#include "routerlist.h"
#include "routerset.h"
#include "control.h"
static extend_info_t *rend_client_get_random_intro_impl(
const rend_cache_entry_t *rend_query,
const int strict, const int warnings);
/** Purge all potentially remotely-detectable state held in the hidden
* service client code. Called on SIGNAL NEWNYM. */
void
rend_client_purge_state(void)
{
rend_cache_purge();
rend_cache_failure_purge();
rend_client_cancel_descriptor_fetches();
rend_client_purge_last_hid_serv_requests();
}
/** Called when we've established a circuit to an introduction point:
* send the introduction request. */
void
rend_client_introcirc_has_opened(origin_circuit_t *circ)
{
tor_assert(circ->base_.purpose == CIRCUIT_PURPOSE_C_INTRODUCING);
tor_assert(circ->cpath);
log_info(LD_REND,"introcirc is open");
connection_ap_attach_pending(1);
}
/** Send the establish-rendezvous cell along a rendezvous circuit. if
* it fails, mark the circ for close and return -1. else return 0.
*/
static int
rend_client_send_establish_rendezvous(origin_circuit_t *circ)
{
tor_assert(circ->base_.purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND);
tor_assert(circ->rend_data);
log_info(LD_REND, "Sending an ESTABLISH_RENDEZVOUS cell");
crypto_rand(circ->rend_data->rend_cookie, REND_COOKIE_LEN);
/* Set timestamp_dirty, because circuit_expire_building expects it,
* and the rend cookie also means we've used the circ. */
circ->base_.timestamp_dirty = time(NULL);
/* We've attempted to use this circuit. Probe it if we fail */
pathbias_count_use_attempt(circ);
if (relay_send_command_from_edge(0, TO_CIRCUIT(circ),
RELAY_COMMAND_ESTABLISH_RENDEZVOUS,
circ->rend_data->rend_cookie,
REND_COOKIE_LEN,
circ->cpath->prev)<0) {
/* circ is already marked for close */
log_warn(LD_GENERAL, "Couldn't send ESTABLISH_RENDEZVOUS cell");
return -1;
}
return 0;
}
/** Extend the introduction circuit <b>circ</b> 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. */
static int
rend_client_reextend_intro_circuit(origin_circuit_t *circ)
{
extend_info_t *extend_info;
int result;
extend_info = rend_client_get_random_intro(circ->rend_data);
if (!extend_info) {
log_warn(LD_REND,
"No usable introduction points left for %s. Closing.",
safe_str_client(circ->rend_data->onion_address));
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL);
return -1;
}
// XXX: should we not re-extend if hs_circ_has_timed_out?
if (circ->remaining_relay_early_cells) {
log_info(LD_REND,
"Re-extending circ %u, this time to %s.",
(unsigned)circ->base_.n_circ_id,
safe_str_client(extend_info_describe(extend_info)));
result = circuit_extend_to_new_exit(circ, extend_info);
} else {
log_info(LD_REND,
"Closing intro circ %u (out of RELAY_EARLY cells).",
(unsigned)circ->base_.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. */
result = 0;
}
extend_info_free(extend_info);
return result;
}
/** Called when we're trying to connect an ap conn; sends an INTRODUCE1 cell
* down introcirc if possible.
*/
int
rend_client_send_introduction(origin_circuit_t *introcirc,
origin_circuit_t *rendcirc)
{
const or_options_t *options = get_options();
size_t payload_len;
int r, v3_shift = 0;
char payload[RELAY_PAYLOAD_SIZE];
char tmp[RELAY_PAYLOAD_SIZE];
rend_cache_entry_t *entry = NULL;
crypt_path_t *cpath;
off_t dh_offset;
crypto_pk_t *intro_key = NULL;
int status = 0;
tor_assert(introcirc->base_.purpose == CIRCUIT_PURPOSE_C_INTRODUCING);
tor_assert(rendcirc->base_.purpose == CIRCUIT_PURPOSE_C_REND_READY);
tor_assert(introcirc->rend_data);
tor_assert(rendcirc->rend_data);
tor_assert(!rend_cmp_service_ids(introcirc->rend_data->onion_address,
rendcirc->rend_data->onion_address));
assert_circ_anonymity_ok(introcirc, options);
assert_circ_anonymity_ok(rendcirc, options);
r = rend_cache_lookup_entry(introcirc->rend_data->onion_address, -1,
&entry);
/* An invalid onion address is not possible else we have a big issue. */
tor_assert(r != -EINVAL);
if (r < 0 || !rend_client_any_intro_points_usable(entry)) {
/* If the descriptor is not found or the intro points are not usable
* anymore, trigger a fetch. */
log_info(LD_REND,
"query %s didn't have valid rend desc in cache. "
"Refetching descriptor.",
safe_str_client(introcirc->rend_data->onion_address));
rend_client_refetch_v2_renddesc(introcirc->rend_data);
{
connection_t *conn;
while ((conn = connection_get_by_type_state_rendquery(CONN_TYPE_AP,
AP_CONN_STATE_CIRCUIT_WAIT,
introcirc->rend_data->onion_address))) {
connection_ap_mark_as_non_pending_circuit(TO_ENTRY_CONN(conn));
conn->state = AP_CONN_STATE_RENDDESC_WAIT;
}
}
status = -1;
goto cleanup;
}
/* first 20 bytes of payload are the hash of the service's pk */
intro_key = NULL;
SMARTLIST_FOREACH(entry->parsed->intro_nodes, rend_intro_point_t *,
intro, {
if (tor_memeq(introcirc->build_state->chosen_exit->identity_digest,
intro->extend_info->identity_digest, DIGEST_LEN)) {
intro_key = intro->intro_key;
break;
}
});
if (!intro_key) {
log_info(LD_REND, "Could not find intro key for %s at %s; we "
"have a v2 rend desc with %d intro points. "
"Trying a different intro point...",
safe_str_client(introcirc->rend_data->onion_address),
safe_str_client(extend_info_describe(
introcirc->build_state->chosen_exit)),
smartlist_len(entry->parsed->intro_nodes));
if (rend_client_reextend_intro_circuit(introcirc)) {
status = -2;
goto perm_err;
} else {
status = -1;
goto cleanup;
}
}
if (crypto_pk_get_digest(intro_key, payload)<0) {
log_warn(LD_BUG, "Internal error: couldn't hash public key.");
status = -2;
goto perm_err;
}
/* Initialize the pending_final_cpath and start the DH handshake. */
cpath = rendcirc->build_state->pending_final_cpath;
if (!cpath) {
cpath = rendcirc->build_state->pending_final_cpath =
tor_malloc_zero(sizeof(crypt_path_t));
cpath->magic = CRYPT_PATH_MAGIC;
if (!(cpath->rend_dh_handshake_state = crypto_dh_new(DH_TYPE_REND))) {
log_warn(LD_BUG, "Internal error: couldn't allocate DH.");
status = -2;
goto perm_err;
}
if (crypto_dh_generate_public(cpath->rend_dh_handshake_state)<0) {
log_warn(LD_BUG, "Internal error: couldn't generate g^x.");
status = -2;
goto perm_err;
}
}
/* If version is 3, write (optional) auth data and timestamp. */
if (entry->parsed->protocols & (1<<3)) {
tmp[0] = 3; /* version 3 of the cell format */
tmp[1] = (uint8_t)introcirc->rend_data->auth_type; /* auth type, if any */
v3_shift = 1;
if (introcirc->rend_data->auth_type != REND_NO_AUTH) {
set_uint16(tmp+2, htons(REND_DESC_COOKIE_LEN));
memcpy(tmp+4, introcirc->rend_data->descriptor_cookie,
REND_DESC_COOKIE_LEN);
v3_shift += 2+REND_DESC_COOKIE_LEN;
}
/* Once this held a timestamp. */
set_uint32(tmp+v3_shift+1, 0);
v3_shift += 4;
} /* if version 2 only write version number */
else if (entry->parsed->protocols & (1<<2)) {
tmp[0] = 2; /* version 2 of the cell format */
}
/* write the remaining items into tmp */
if (entry->parsed->protocols & (1<<3) || entry->parsed->protocols & (1<<2)) {
/* version 2 format */
extend_info_t *extend_info = rendcirc->build_state->chosen_exit;
int klen;
/* nul pads */
set_uint32(tmp+v3_shift+1, tor_addr_to_ipv4n(&extend_info->addr));
set_uint16(tmp+v3_shift+5, htons(extend_info->port));
memcpy(tmp+v3_shift+7, extend_info->identity_digest, DIGEST_LEN);
klen = crypto_pk_asn1_encode(extend_info->onion_key,
tmp+v3_shift+7+DIGEST_LEN+2,
sizeof(tmp)-(v3_shift+7+DIGEST_LEN+2));
set_uint16(tmp+v3_shift+7+DIGEST_LEN, htons(klen));
memcpy(tmp+v3_shift+7+DIGEST_LEN+2+klen, rendcirc->rend_data->rend_cookie,
REND_COOKIE_LEN);
dh_offset = v3_shift+7+DIGEST_LEN+2+klen+REND_COOKIE_LEN;
} else {
/* Version 0. */
strncpy(tmp, rendcirc->build_state->chosen_exit->nickname,
(MAX_NICKNAME_LEN+1)); /* nul pads */
memcpy(tmp+MAX_NICKNAME_LEN+1, rendcirc->rend_data->rend_cookie,
REND_COOKIE_LEN);
dh_offset = MAX_NICKNAME_LEN+1+REND_COOKIE_LEN;
}
if (crypto_dh_get_public(cpath->rend_dh_handshake_state, tmp+dh_offset,
DH_KEY_LEN)<0) {
log_warn(LD_BUG, "Internal error: couldn't extract g^x.");
status = -2;
goto perm_err;
}
note_crypto_pk_op(REND_CLIENT);
/*XXX maybe give crypto_pk_public_hybrid_encrypt a max_len arg,
* to avoid buffer overflows? */
r = crypto_pk_public_hybrid_encrypt(intro_key, payload+DIGEST_LEN,
sizeof(payload)-DIGEST_LEN,
tmp,
(int)(dh_offset+DH_KEY_LEN),
PK_PKCS1_OAEP_PADDING, 0);
if (r<0) {
log_warn(LD_BUG,"Internal error: hybrid pk encrypt failed.");
status = -2;
goto perm_err;
}
payload_len = DIGEST_LEN + r;
tor_assert(payload_len <= RELAY_PAYLOAD_SIZE); /* we overran something */
/* Copy the rendezvous cookie from rendcirc to introcirc, so that
* when introcirc gets an ack, we can change the state of the right
* rendezvous circuit. */
memcpy(introcirc->rend_data->rend_cookie, rendcirc->rend_data->rend_cookie,
REND_COOKIE_LEN);
log_info(LD_REND, "Sending an INTRODUCE1 cell");
if (relay_send_command_from_edge(0, TO_CIRCUIT(introcirc),
RELAY_COMMAND_INTRODUCE1,
payload, payload_len,
introcirc->cpath->prev)<0) {
/* introcirc is already marked for close. leave rendcirc alone. */
log_warn(LD_BUG, "Couldn't send INTRODUCE1 cell");
status = -2;
goto cleanup;
}
/* Now, we wait for an ACK or NAK on this circuit. */
circuit_change_purpose(TO_CIRCUIT(introcirc),
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. */
introcirc->base_.timestamp_dirty = time(NULL);
pathbias_count_use_attempt(introcirc);
goto cleanup;
perm_err:
if (!introcirc->base_.marked_for_close)
circuit_mark_for_close(TO_CIRCUIT(introcirc), END_CIRC_REASON_INTERNAL);
circuit_mark_for_close(TO_CIRCUIT(rendcirc), END_CIRC_REASON_INTERNAL);
cleanup:
memwipe(payload, 0, sizeof(payload));
memwipe(tmp, 0, sizeof(tmp));
return status;
}
/** Called when a rendezvous circuit is open; sends a establish
* rendezvous circuit as appropriate. */
void
rend_client_rendcirc_has_opened(origin_circuit_t *circ)
{
tor_assert(circ->base_.purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND);
log_info(LD_REND,"rendcirc is open");
/* generate a rendezvous cookie, store it in circ */
if (rend_client_send_establish_rendezvous(circ) < 0) {
return;
}
}
/**
* Called to close other intro circuits we launched in parallel.
*/
static void
rend_client_close_other_intros(const char *onion_address)
{
/* abort parallel intro circs, if any */
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, c) {
if ((c->purpose == CIRCUIT_PURPOSE_C_INTRODUCING ||
c->purpose == CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) &&
!c->marked_for_close && CIRCUIT_IS_ORIGIN(c)) {
origin_circuit_t *oc = TO_ORIGIN_CIRCUIT(c);
if (oc->rend_data &&
!rend_cmp_service_ids(onion_address,
oc->rend_data->onion_address)) {
log_info(LD_REND|LD_CIRC, "Closing introduction circuit %d that we "
"built in parallel (Purpose %d).", oc->global_identifier,
c->purpose);
circuit_mark_for_close(c, END_CIRC_REASON_IP_NOW_REDUNDANT);
}
}
}
SMARTLIST_FOREACH_END(c);
}
/** Called when get an ACK or a NAK for a REND_INTRODUCE1 cell.
*/
int
rend_client_introduction_acked(origin_circuit_t *circ,
const uint8_t *request, size_t request_len)
{
const or_options_t *options = get_options();
origin_circuit_t *rendcirc;
(void) request; // XXXX Use this.
if (circ->base_.purpose != CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT) {
log_warn(LD_PROTOCOL,
"Received REND_INTRODUCE_ACK on unexpected circuit %u.",
(unsigned)circ->base_.n_circ_id);
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
return -1;
}
tor_assert(circ->build_state);
tor_assert(circ->build_state->chosen_exit);
assert_circ_anonymity_ok(circ, options);
tor_assert(circ->rend_data);
/* For path bias: This circuit was used successfully. Valid
* nacks and acks count. */
pathbias_mark_use_success(circ);
if (request_len == 0) {
/* It's an ACK; the introduction point relayed our introduction request. */
/* Locate the rend circ which is waiting to hear about this ack,
* and tell it.
*/
log_info(LD_REND,"Received ack. Telling rend circ...");
rendcirc = circuit_get_ready_rend_circ_by_rend_data(circ->rend_data);
if (rendcirc) { /* remember the ack */
assert_circ_anonymity_ok(rendcirc, options);
circuit_change_purpose(TO_CIRCUIT(rendcirc),
CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED);
/* Set timestamp_dirty, because circuit_expire_building expects
* it to specify when a circuit entered the
* _C_REND_READY_INTRO_ACKED state. */
rendcirc->base_.timestamp_dirty = time(NULL);
} else {
log_info(LD_REND,"...Found no rend circ. Dropping on the floor.");
}
/* close the circuit: we won't need it anymore. */
circuit_change_purpose(TO_CIRCUIT(circ),
CIRCUIT_PURPOSE_C_INTRODUCE_ACKED);
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED);
/* close any other intros launched in parallel */
rend_client_close_other_intros(circ->rend_data->onion_address);
} else {
/* It's a NAK; the introduction point didn't relay our request. */
circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_INTRODUCING);
/* Remove this intro point from the set of viable introduction
* points. If any remain, extend to a new one and try again.
* If none remain, refetch the service descriptor.
*/
log_info(LD_REND, "Got nack for %s from %s...",
safe_str_client(circ->rend_data->onion_address),
safe_str_client(extend_info_describe(circ->build_state->chosen_exit)));
if (rend_client_report_intro_point_failure(circ->build_state->chosen_exit,
circ->rend_data,
INTRO_POINT_FAILURE_GENERIC)>0) {
/* There are introduction points left. Re-extend the circuit to
* another intro point and try again. */
int result = rend_client_reextend_intro_circuit(circ);
/* XXXX If that call failed, should we close the rend circuit,
* too? */
return result;
} else {
/* Close circuit because no more intro points are usable thus not
* useful anymore. Change it's purpose before so we don't report an
* intro point failure again triggering an extra descriptor fetch. */
circuit_change_purpose(TO_CIRCUIT(circ),
CIRCUIT_PURPOSE_C_INTRODUCE_ACKED);
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED);
}
}
return 0;
}
/** The period for which a hidden service directory cannot be queried for
* the same descriptor ID again. */
#define REND_HID_SERV_DIR_REQUERY_PERIOD (15 * 60)
/** Test networks generate a new consensus every 5 or 10 seconds.
* So allow them to requery HSDirs much faster. */
#define REND_HID_SERV_DIR_REQUERY_PERIOD_TESTING (5)
/** Return the period for which a hidden service directory cannot be queried
* for the same descriptor ID again, taking TestingTorNetwork into account. */
static time_t
hsdir_requery_period(const or_options_t *options)
{
tor_assert(options);
if (options->TestingTorNetwork) {
return REND_HID_SERV_DIR_REQUERY_PERIOD_TESTING;
} else {
return REND_HID_SERV_DIR_REQUERY_PERIOD;
}
}
/** Contains the last request times to hidden service directories for
* certain queries; each key is a string consisting of the
* concatenation of a base32-encoded HS directory identity digest and
* base32-encoded HS descriptor ID; each value is a pointer to a time_t
* holding the time of the last request for that descriptor ID to that
* HS directory. */
static strmap_t *last_hid_serv_requests_ = NULL;
/** Returns last_hid_serv_requests_, initializing it to a new strmap if
* necessary. */
static strmap_t *
get_last_hid_serv_requests(void)
{
if (!last_hid_serv_requests_)
last_hid_serv_requests_ = strmap_new();
return last_hid_serv_requests_;
}
#define LAST_HID_SERV_REQUEST_KEY_LEN (REND_DESC_ID_V2_LEN_BASE32 + \
REND_DESC_ID_V2_LEN_BASE32)
/** Look up the last request time to hidden service directory <b>hs_dir</b>
* for descriptor ID <b>desc_id_base32</b>. If <b>set</b> is non-zero,
* assign the current time <b>now</b> and return that. Otherwise, return the
* most recent request time, or 0 if no such request has been sent before.
*/
static time_t
lookup_last_hid_serv_request(routerstatus_t *hs_dir,
const char *desc_id_base32,
time_t now, int set)
{
char hsdir_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
char hsdir_desc_comb_id[LAST_HID_SERV_REQUEST_KEY_LEN + 1];
time_t *last_request_ptr;
strmap_t *last_hid_serv_requests = get_last_hid_serv_requests();
base32_encode(hsdir_id_base32, sizeof(hsdir_id_base32),
hs_dir->identity_digest, DIGEST_LEN);
tor_snprintf(hsdir_desc_comb_id, sizeof(hsdir_desc_comb_id), "%s%s",
hsdir_id_base32,
desc_id_base32);
/* XXX++?? tor_assert(strlen(hsdir_desc_comb_id) ==
LAST_HID_SERV_REQUEST_KEY_LEN); */
if (set) {
time_t *oldptr;
last_request_ptr = tor_malloc_zero(sizeof(time_t));
*last_request_ptr = now;
oldptr = strmap_set(last_hid_serv_requests, hsdir_desc_comb_id,
last_request_ptr);
tor_free(oldptr);
} else
last_request_ptr = strmap_get_lc(last_hid_serv_requests,
hsdir_desc_comb_id);
return (last_request_ptr) ? *last_request_ptr : 0;
}
/** Clean the history of request times to hidden service directories, so that
* it does not contain requests older than REND_HID_SERV_DIR_REQUERY_PERIOD
* seconds any more. */
static void
directory_clean_last_hid_serv_requests(time_t now)
{
strmap_iter_t *iter;
time_t cutoff = now - hsdir_requery_period(get_options());
strmap_t *last_hid_serv_requests = get_last_hid_serv_requests();
for (iter = strmap_iter_init(last_hid_serv_requests);
!strmap_iter_done(iter); ) {
const char *key;
void *val;
time_t *ent;
strmap_iter_get(iter, &key, &val);
ent = (time_t *) val;
if (*ent < cutoff) {
iter = strmap_iter_next_rmv(last_hid_serv_requests, iter);
tor_free(ent);
} else {
iter = strmap_iter_next(last_hid_serv_requests, iter);
}
}
}
/** Remove all requests related to the descriptor ID <b>desc_id</b> from the
* history of times of requests to hidden service directories.
* <b>desc_id</b> is an unencoded descriptor ID of size DIGEST_LEN.
*
* This is called from rend_client_note_connection_attempt_ended(), which
* must be idempotent, so any future changes to this function must leave it
* idempotent too. */
static void
purge_hid_serv_from_last_hid_serv_requests(const char *desc_id)
{
strmap_iter_t *iter;
strmap_t *last_hid_serv_requests = get_last_hid_serv_requests();
char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
/* Key is stored with the base32 encoded desc_id. */
base32_encode(desc_id_base32, sizeof(desc_id_base32), desc_id,
DIGEST_LEN);
for (iter = strmap_iter_init(last_hid_serv_requests);
!strmap_iter_done(iter); ) {
const char *key;
void *val;
strmap_iter_get(iter, &key, &val);
/* XXX++?? tor_assert(strlen(key) == LAST_HID_SERV_REQUEST_KEY_LEN); */
if (tor_memeq(key + LAST_HID_SERV_REQUEST_KEY_LEN -
REND_DESC_ID_V2_LEN_BASE32,
desc_id_base32,
REND_DESC_ID_V2_LEN_BASE32)) {
iter = strmap_iter_next_rmv(last_hid_serv_requests, iter);
tor_free(val);
} else {
iter = strmap_iter_next(last_hid_serv_requests, iter);
}
}
}
/** Purge the history of request times to hidden service directories,
* so that future lookups of an HS descriptor will not fail because we
* accessed all of the HSDir relays responsible for the descriptor
* recently. */
void
rend_client_purge_last_hid_serv_requests(void)
{
/* Don't create the table if it doesn't exist yet (and it may very
* well not exist if the user hasn't accessed any HSes)... */
strmap_t *old_last_hid_serv_requests = last_hid_serv_requests_;
/* ... and let get_last_hid_serv_requests re-create it for us if
* necessary. */
last_hid_serv_requests_ = NULL;
if (old_last_hid_serv_requests != NULL) {
log_info(LD_REND, "Purging client last-HS-desc-request-time table");
strmap_free(old_last_hid_serv_requests, tor_free_);
}
}
/** This returns a good valid hs dir that should be used for the given
* descriptor id.
*
* Return NULL on error else the hsdir node pointer. */
static routerstatus_t *
pick_hsdir(const char *desc_id, const char *desc_id_base32)
{
smartlist_t *responsible_dirs = smartlist_new();
smartlist_t *usable_responsible_dirs = smartlist_new();
const or_options_t *options = get_options();
routerstatus_t *hs_dir;
time_t now = time(NULL);
int excluded_some;
tor_assert(desc_id);
tor_assert(desc_id_base32);
/* Determine responsible dirs. Even if we can't get all we want, work with
* the ones we have. If it's empty, we'll notice below. */
hid_serv_get_responsible_directories(responsible_dirs, desc_id);
/* Clean request history first. */
directory_clean_last_hid_serv_requests(now);
/* Only select those hidden service directories to which we did not send a
* request recently and for which we have a router descriptor here. */
SMARTLIST_FOREACH_BEGIN(responsible_dirs, routerstatus_t *, dir) {
time_t last = lookup_last_hid_serv_request(dir, desc_id_base32,
0, 0);
const node_t *node = node_get_by_id(dir->identity_digest);
if (last + hsdir_requery_period(options) >= now ||
!node || !node_has_descriptor(node)) {
SMARTLIST_DEL_CURRENT(responsible_dirs, dir);
continue;
}
if (!routerset_contains_node(options->ExcludeNodes, node)) {
smartlist_add(usable_responsible_dirs, dir);
}
} SMARTLIST_FOREACH_END(dir);
excluded_some =
smartlist_len(usable_responsible_dirs) < smartlist_len(responsible_dirs);
hs_dir = smartlist_choose(usable_responsible_dirs);
if (!hs_dir && !options->StrictNodes) {
hs_dir = smartlist_choose(responsible_dirs);
}
smartlist_free(responsible_dirs);
smartlist_free(usable_responsible_dirs);
if (!hs_dir) {
log_info(LD_REND, "Could not pick one of the responsible hidden "
"service directories, because we requested them all "
"recently without success.");
if (options->StrictNodes && excluded_some) {
log_warn(LD_REND, "Could not pick a hidden service directory for the "
"requested hidden service: they are all either down or "
"excluded, and StrictNodes is set.");
}
} else {
/* Remember that we are requesting a descriptor from this hidden service
* directory now. */
lookup_last_hid_serv_request(hs_dir, desc_id_base32, now, 1);
}
return hs_dir;
}
/** Determine the responsible hidden service directories for <b>desc_id</b>
* and fetch the descriptor with that ID from one of them. Only
* send a request to a hidden service directory that we have not yet tried
* during this attempt to connect to this hidden service; on success, return 1,
* in the case that no hidden service directory is left to ask for the
* descriptor, return 0, and in case of a failure -1. */
static int
directory_get_from_hs_dir(const char *desc_id, const rend_data_t *rend_query,
routerstatus_t *rs_hsdir)
{
routerstatus_t *hs_dir = rs_hsdir;
char *hsdir_fp;
char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
char descriptor_cookie_base64[3*REND_DESC_COOKIE_LEN_BASE64];
#ifdef ENABLE_TOR2WEB_MODE
const int tor2web_mode = get_options()->Tor2webMode;
const int how_to_fetch = tor2web_mode ? DIRIND_ONEHOP : DIRIND_ANONYMOUS;
#else
const int how_to_fetch = DIRIND_ANONYMOUS;
#endif
tor_assert(desc_id);
base32_encode(desc_id_base32, sizeof(desc_id_base32),
desc_id, DIGEST_LEN);
/* Automatically pick an hs dir if none given. */
if (!rs_hsdir) {
hs_dir = pick_hsdir(desc_id, desc_id_base32);
if (!hs_dir) {
/* No suitable hs dir can be found, stop right now. */
return 0;
}
}
/* Add a copy of the HSDir identity digest to the query so we can track it
* on the control port. */
hsdir_fp = tor_memdup(hs_dir->identity_digest,
sizeof(hs_dir->identity_digest));
smartlist_add(rend_query->hsdirs_fp, hsdir_fp);
/* Encode descriptor cookie for logging purposes. Also, if the cookie is
* malformed, no fetch is triggered thus this needs to be done before the
* fetch request. */
if (rend_query->auth_type != REND_NO_AUTH) {
if (base64_encode(descriptor_cookie_base64,
sizeof(descriptor_cookie_base64),
rend_query->descriptor_cookie, REND_DESC_COOKIE_LEN,
0)<0) {
log_warn(LD_BUG, "Could not base64-encode descriptor cookie.");
return 0;
}
/* Remove == signs. */
descriptor_cookie_base64[strlen(descriptor_cookie_base64)-2] = '\0';
} else {
strlcpy(descriptor_cookie_base64, "(none)",
sizeof(descriptor_cookie_base64));
}
/* Send fetch request. (Pass query and possibly descriptor cookie so that
* they can be written to the directory connection and be referred to when
* the response arrives. */
directory_initiate_command_routerstatus_rend(hs_dir,
DIR_PURPOSE_FETCH_RENDDESC_V2,
ROUTER_PURPOSE_GENERAL,
how_to_fetch,
desc_id_base32,
NULL, 0, 0,
rend_query);
log_info(LD_REND, "Sending fetch request for v2 descriptor for "
"service '%s' with descriptor ID '%s', auth type %d, "
"and descriptor cookie '%s' to hidden service "
"directory %s",
rend_query->onion_address, desc_id_base32,
rend_query->auth_type,
(rend_query->auth_type == REND_NO_AUTH ? "[none]" :
escaped_safe_str_client(descriptor_cookie_base64)),
routerstatus_describe(hs_dir));
control_event_hs_descriptor_requested(rend_query,
hs_dir->identity_digest,
desc_id_base32);
return 1;
}
/** Fetch a v2 descriptor using the given descriptor id. If any hsdir(s) are
* given, they will be used instead.
*
* On success, 1 is returned. If no hidden service is left to ask, return 0.
* On error, -1 is returned. */
static int
fetch_v2_desc_by_descid(const char *desc_id, const rend_data_t *rend_query,
smartlist_t *hsdirs)
{
int ret;
tor_assert(rend_query);
if (!hsdirs) {
ret = directory_get_from_hs_dir(desc_id, rend_query, NULL);
goto end; /* either success or failure, but we're done */
}
/* Using the given hsdir list, trigger a fetch on each of them. */
SMARTLIST_FOREACH_BEGIN(hsdirs, routerstatus_t *, hs_dir) {
/* This should always be a success. */
ret = directory_get_from_hs_dir(desc_id, rend_query, hs_dir);
tor_assert(ret);
} SMARTLIST_FOREACH_END(hs_dir);
/* Everything went well. */
ret = 0;
end:
return ret;
}
/** Fetch a v2 descriptor using the onion address in the given query object.
* This will compute the descriptor id for each replicas and fetch it on the
* given hsdir(s) if any or the responsible ones that are choosen
* automatically.
*
* On success, 1 is returned. If no hidden service is left to ask, return 0.
* On error, -1 is returned. */
static int
fetch_v2_desc_by_addr(rend_data_t *query, smartlist_t *hsdirs)
{
char descriptor_id[DIGEST_LEN];
int replicas_left_to_try[REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS];
int i, tries_left, ret;
tor_assert(query);
/* Randomly iterate over the replicas until a descriptor can be fetched
* from one of the consecutive nodes, or no options are left. */
for (i = 0; i < REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS; i++) {
replicas_left_to_try[i] = i;
}
tries_left = REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS;
while (tries_left > 0) {
int rand_val = crypto_rand_int(tries_left);
int chosen_replica = replicas_left_to_try[rand_val];
replicas_left_to_try[rand_val] = replicas_left_to_try[--tries_left];
ret = rend_compute_v2_desc_id(descriptor_id, query->onion_address,
query->auth_type == REND_STEALTH_AUTH ?
query->descriptor_cookie : NULL,
time(NULL), chosen_replica);
if (ret < 0) {
/* Normally, on failure the descriptor_id is untouched but let's be
* safe in general in case the function changes at some point. */
goto end;
}
if (tor_memcmp(descriptor_id, query->descriptor_id[chosen_replica],
sizeof(descriptor_id)) != 0) {
/* Not equal from what we currently have so purge the last hid serv
* request cache and update the descriptor ID with the new value. */
purge_hid_serv_from_last_hid_serv_requests(
query->descriptor_id[chosen_replica]);
memcpy(query->descriptor_id[chosen_replica], descriptor_id,
sizeof(query->descriptor_id[chosen_replica]));
}
/* Trigger the fetch with the computed descriptor ID. */
ret = fetch_v2_desc_by_descid(descriptor_id, query, hsdirs);
if (ret != 0) {
/* Either on success or failure, as long as we tried a fetch we are
* done here. */
goto end;
}
}
/* If we come here, there are no hidden service directories left. */
log_info(LD_REND, "Could not pick one of the responsible hidden "
"service directories to fetch descriptors, because "
"we already tried them all unsuccessfully.");
ret = 0;
end:
memwipe(descriptor_id, 0, sizeof(descriptor_id));
return ret;
}
/** Fetch a v2 descriptor using the given query. If any hsdir are specified,
* use them for the fetch.
*
* On success, 1 is returned. If no hidden service is left to ask, return 0.
* On error, -1 is returned. */
int
rend_client_fetch_v2_desc(rend_data_t *query, smartlist_t *hsdirs)
{
int ret;
tor_assert(query);
/* Depending on what's available in the rend data query object, we will
* trigger a fetch by HS address or using a descriptor ID. */
if (query->onion_address[0] != '\0') {
ret = fetch_v2_desc_by_addr(query, hsdirs);
} else if (!tor_digest_is_zero(query->desc_id_fetch)) {
ret = fetch_v2_desc_by_descid(query->desc_id_fetch, query, hsdirs);
} else {
/* Query data is invalid. */
ret = -1;
goto error;
}
error:
return ret;
}
/** Unless we already have a descriptor for <b>rend_query</b> with at least
* one (possibly) working introduction point in it, start a connection to a
* hidden service directory to fetch a v2 rendezvous service descriptor. */
void
rend_client_refetch_v2_renddesc(rend_data_t *rend_query)
{
rend_cache_entry_t *e = NULL;
tor_assert(rend_query);
/* Before fetching, check if we already have a usable descriptor here. */
if (rend_cache_lookup_entry(rend_query->onion_address, -1, &e) == 0 &&
rend_client_any_intro_points_usable(e)) {
log_info(LD_REND, "We would fetch a v2 rendezvous descriptor, but we "
"already have a usable descriptor here. Not fetching.");
return;
}
/* Are we configured to fetch descriptors? */
if (!get_options()->FetchHidServDescriptors) {
log_warn(LD_REND, "We received an onion address for a v2 rendezvous "
"service descriptor, but are not fetching service descriptors.");
return;
}
log_debug(LD_REND, "Fetching v2 rendezvous descriptor for service %s",
safe_str_client(rend_query->onion_address));
rend_client_fetch_v2_desc(rend_query, NULL);
/* We don't need to look the error code because either on failure or
* success, the necessary steps to continue the HS connection will be
* triggered once the descriptor arrives or if all fetch failed. */
return;
}
/** Cancel all rendezvous descriptor fetches currently in progress.
*/
void
rend_client_cancel_descriptor_fetches(void)
{
smartlist_t *connection_array = get_connection_array();
SMARTLIST_FOREACH_BEGIN(connection_array, connection_t *, conn) {
if (conn->type == CONN_TYPE_DIR &&
conn->purpose == DIR_PURPOSE_FETCH_RENDDESC_V2) {
/* It's a rendezvous descriptor fetch in progress -- cancel it
* by marking the connection for close.
*
* Even if this connection has already reached EOF, this is
* enough to make sure that if the descriptor hasn't been
* processed yet, it won't be. See the end of
* connection_handle_read; connection_reached_eof (indirectly)
* processes whatever response the connection received. */
const rend_data_t *rd = (TO_DIR_CONN(conn))->rend_data;
if (!rd) {
log_warn(LD_BUG | LD_REND,
"Marking for close dir conn fetching rendezvous "
"descriptor for unknown service!");
} else {
log_debug(LD_REND, "Marking for close dir conn fetching "
"rendezvous descriptor for service %s",
safe_str(rd->onion_address));
}
connection_mark_for_close(conn);
}
} SMARTLIST_FOREACH_END(conn);
}
/** Mark <b>failed_intro</b> as a failed introduction point for the
* hidden service specified by <b>rend_query</b>. If the HS now has no
* usable intro points, or we do not have an HS descriptor for it,
* then launch a new renddesc fetch.
*
* If <b>failure_type</b> is INTRO_POINT_FAILURE_GENERIC, remove the
* intro point from (our parsed copy of) the HS descriptor.
*
* If <b>failure_type</b> is INTRO_POINT_FAILURE_TIMEOUT, mark the
* intro point as 'timed out'; it will not be retried until the
* current hidden service connection attempt has ended or it has
* appeared in a newly fetched rendezvous descriptor.
*
* If <b>failure_type</b> is INTRO_POINT_FAILURE_UNREACHABLE,
* increment the intro point's reachability-failure count; if it has
* now failed MAX_INTRO_POINT_REACHABILITY_FAILURES or more times,
* remove the intro point from (our parsed copy of) the HS descriptor.
*
* Return -1 if error, 0 if no usable intro points remain or service
* unrecognized, 1 if recognized and some intro points remain.
*/
int
rend_client_report_intro_point_failure(extend_info_t *failed_intro,
rend_data_t *rend_query,
unsigned int failure_type)
{
int i, r;
rend_cache_entry_t *ent;
connection_t *conn;
r = rend_cache_lookup_entry(rend_query->onion_address, -1, &ent);
if (r < 0) {
/* Either invalid onion address or cache entry not found. */
switch (-r) {
case EINVAL:
log_warn(LD_BUG, "Malformed service ID %s.",
escaped_safe_str_client(rend_query->onion_address));
return -1;
case ENOENT:
log_info(LD_REND, "Unknown service %s. Re-fetching descriptor.",
escaped_safe_str_client(rend_query->onion_address));
rend_client_refetch_v2_renddesc(rend_query);
return 0;
default:
log_warn(LD_BUG, "Unknown cache lookup returned code: %d", r);
return -1;
}
}
/* The intro points are not checked here if they are usable or not because
* this is called when an intro point circuit is closed thus there must be
* at least one intro point that is usable and is about to be flagged. */
for (i = 0; i < smartlist_len(ent->parsed->intro_nodes); i++) {
rend_intro_point_t *intro = smartlist_get(ent->parsed->intro_nodes, i);
if (tor_memeq(failed_intro->identity_digest,
intro->extend_info->identity_digest, DIGEST_LEN)) {
switch (failure_type) {
default:
log_warn(LD_BUG, "Unknown failure type %u. Removing intro point.",
failure_type);
tor_fragile_assert();
/* fall through */
case INTRO_POINT_FAILURE_GENERIC:
rend_cache_intro_failure_note(failure_type,
(uint8_t *)failed_intro->identity_digest,
rend_query->onion_address);
rend_intro_point_free(intro);
smartlist_del(ent->parsed->intro_nodes, i);
break;
case INTRO_POINT_FAILURE_TIMEOUT:
intro->timed_out = 1;
break;
case INTRO_POINT_FAILURE_UNREACHABLE:
++(intro->unreachable_count);
{
int zap_intro_point =
intro->unreachable_count >= MAX_INTRO_POINT_REACHABILITY_FAILURES;
log_info(LD_REND, "Failed to reach this intro point %u times.%s",
intro->unreachable_count,
zap_intro_point ? " Removing from descriptor.": "");
if (zap_intro_point) {
rend_cache_intro_failure_note(
failure_type,
(uint8_t *) failed_intro->identity_digest,
rend_query->onion_address);
rend_intro_point_free(intro);
smartlist_del(ent->parsed->intro_nodes, i);
}
}
break;
}
break;
}
}
if (! rend_client_any_intro_points_usable(ent)) {
log_info(LD_REND,
"No more intro points remain for %s. Re-fetching descriptor.",
escaped_safe_str_client(rend_query->onion_address));
rend_client_refetch_v2_renddesc(rend_query);
/* move all pending streams back to renddesc_wait */
/* NOTE: We can now do this faster, if we use pending_entry_connections */
while ((conn = connection_get_by_type_state_rendquery(CONN_TYPE_AP,
AP_CONN_STATE_CIRCUIT_WAIT,
rend_query->onion_address))) {
connection_ap_mark_as_non_pending_circuit(TO_ENTRY_CONN(conn));
conn->state = AP_CONN_STATE_RENDDESC_WAIT;
}
return 0;
}
log_info(LD_REND,"%d options left for %s.",
smartlist_len(ent->parsed->intro_nodes),
escaped_safe_str_client(rend_query->onion_address));
return 1;
}
/** Called when we receive a RENDEZVOUS_ESTABLISHED cell; changes the state of
* the circuit to C_REND_READY.
*/
int
rend_client_rendezvous_acked(origin_circuit_t *circ, const uint8_t *request,
size_t request_len)
{
(void) request;
(void) request_len;
/* we just got an ack for our establish-rendezvous. switch purposes. */
if (circ->base_.purpose != CIRCUIT_PURPOSE_C_ESTABLISH_REND) {
log_warn(LD_PROTOCOL,"Got a rendezvous ack when we weren't expecting one. "
"Closing circ.");
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
return -1;
}
log_info(LD_REND,"Got rendezvous ack. 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. */
circ->base_.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);
/* XXXX++ This is a pretty brute-force approach. It'd be better to
* attach only the connections that are waiting on this circuit, rather
* than trying to attach them all. See comments bug 743. */
/* If we already have the introduction circuit built, make sure we send
* the INTRODUCE cell _now_ */
connection_ap_attach_pending(1);
return 0;
}
/** The service sent us a rendezvous cell; join the circuits. */
int
rend_client_receive_rendezvous(origin_circuit_t *circ, const uint8_t *request,
size_t request_len)
{
crypt_path_t *hop;
char keys[DIGEST_LEN+CPATH_KEY_MATERIAL_LEN];
if ((circ->base_.purpose != CIRCUIT_PURPOSE_C_REND_READY &&
circ->base_.purpose != CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED)
|| !circ->build_state->pending_final_cpath) {
log_warn(LD_PROTOCOL,"Got rendezvous2 cell from hidden service, but not "
"expecting it. Closing.");
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
return -1;
}
if (request_len != DH_KEY_LEN+DIGEST_LEN) {
log_warn(LD_PROTOCOL,"Incorrect length (%d) on RENDEZVOUS2 cell.",
(int)request_len);
goto err;
}
log_info(LD_REND,"Got RENDEZVOUS2 cell from hidden service.");
/* first DH_KEY_LEN bytes are g^y from the service. Finish the dh
* handshake...*/
tor_assert(circ->build_state);
tor_assert(circ->build_state->pending_final_cpath);
hop = circ->build_state->pending_final_cpath;
tor_assert(hop->rend_dh_handshake_state);
if (crypto_dh_compute_secret(LOG_PROTOCOL_WARN,
hop->rend_dh_handshake_state, (char*)request,
DH_KEY_LEN,
keys, DIGEST_LEN+CPATH_KEY_MATERIAL_LEN)<0) {
log_warn(LD_GENERAL, "Couldn't complete DH handshake.");
goto err;
}
/* ... and set up cpath. */
if (circuit_init_cpath_crypto(hop, keys+DIGEST_LEN, 0)<0)
goto err;
/* Check whether the digest is right... */
if (tor_memneq(keys, request+DH_KEY_LEN, DIGEST_LEN)) {
log_warn(LD_PROTOCOL, "Incorrect digest of key material.");
goto err;
}
crypto_dh_free(hop->rend_dh_handshake_state);
hop->rend_dh_handshake_state = NULL;
/* All is well. Extend the circuit. */
circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_C_REND_JOINED);
hop->state = CPATH_STATE_OPEN;
/* set the windows to default. these are the windows
* that the client thinks the service has.
*/
hop->package_window = circuit_initial_package_window();
hop->deliver_window = CIRCWINDOW_START;
/* Now that this circuit has finished connecting to its destination,
* make sure circuit_get_open_circ_or_launch is willing to return it
* so we can actually use it. */
circ->hs_circ_has_timed_out = 0;
onion_append_to_cpath(&circ->cpath, hop);
circ->build_state->pending_final_cpath = NULL; /* prevent double-free */
circuit_try_attaching_streams(circ);
memwipe(keys, 0, sizeof(keys));
return 0;
err:
memwipe(keys, 0, sizeof(keys));
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
return -1;
}
/** Find all the apconns in state AP_CONN_STATE_RENDDESC_WAIT that are
* waiting on <b>query</b>. If there's a working cache entry here with at
* least one intro point, move them to the next state. */
void
rend_client_desc_trynow(const char *query)
{
entry_connection_t *conn;
rend_cache_entry_t *entry;
const rend_data_t *rend_data;
time_t now = time(NULL);
smartlist_t *conns = get_connection_array();
SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
if (base_conn->type != CONN_TYPE_AP ||
base_conn->state != AP_CONN_STATE_RENDDESC_WAIT ||
base_conn->marked_for_close)
continue;
conn = TO_ENTRY_CONN(base_conn);
rend_data = ENTRY_TO_EDGE_CONN(conn)->rend_data;
if (!rend_data)
continue;
if (rend_cmp_service_ids(query, rend_data->onion_address))
continue;
assert_connection_ok(base_conn, now);
if (rend_cache_lookup_entry(rend_data->onion_address, -1,
&entry) == 0 &&
rend_client_any_intro_points_usable(entry)) {
/* either this fetch worked, or it failed but there was a
* valid entry from before which we should reuse */
log_info(LD_REND,"Rend desc is usable. Launching circuits.");
base_conn->state = AP_CONN_STATE_CIRCUIT_WAIT;
/* restart their timeout values, so they get a fair shake at
* connecting to the hidden service. */
base_conn->timestamp_created = now;
base_conn->timestamp_lastread = now;
base_conn->timestamp_lastwritten = now;
connection_ap_mark_as_pending_circuit(conn);
} else { /* 404, or fetch didn't get that far */
log_notice(LD_REND,"Closing stream for '%s.onion': hidden service is "
"unavailable (try again later).",
safe_str_client(query));
connection_mark_unattached_ap(conn, END_STREAM_REASON_RESOLVEFAILED);
rend_client_note_connection_attempt_ended(rend_data);
}
} SMARTLIST_FOREACH_END(base_conn);
}
/** Clear temporary state used only during an attempt to connect to the
* hidden service with <b>rend_data</b>. Called when a connection attempt
* has ended; it is possible for this to be called multiple times while
* handling an ended connection attempt, and any future changes to this
* function must ensure it remains idempotent. */
void
rend_client_note_connection_attempt_ended(const rend_data_t *rend_data)
{
unsigned int have_onion = 0;
rend_cache_entry_t *cache_entry = NULL;
if (*rend_data->onion_address != '\0') {
/* Ignore return value; we find an entry, or we don't. */
(void) rend_cache_lookup_entry(rend_data->onion_address, -1,
&cache_entry);
have_onion = 1;
}
/* Clear the timed_out flag on all remaining intro points for this HS. */
if (cache_entry != NULL) {
SMARTLIST_FOREACH(cache_entry->parsed->intro_nodes,
rend_intro_point_t *, ip,
ip->timed_out = 0; );
}
/* Remove the HS's entries in last_hid_serv_requests. */
if (have_onion) {
unsigned int replica;
for (replica = 0; replica < ARRAY_LENGTH(rend_data->descriptor_id);
replica++) {
const char *desc_id = rend_data->descriptor_id[replica];
purge_hid_serv_from_last_hid_serv_requests(desc_id);
}
log_info(LD_REND, "Connection attempt for %s has ended; "
"cleaning up temporary state.",
safe_str_client(rend_data->onion_address));
} else {
/* We only have an ID for a fetch. Probably used by HSFETCH. */
purge_hid_serv_from_last_hid_serv_requests(rend_data->desc_id_fetch);
}
}
/** Return a newly allocated extend_info_t* for a randomly chosen introduction
* point for the named hidden service. Return NULL if all introduction points
* have been tried and failed.
*/
extend_info_t *
rend_client_get_random_intro(const rend_data_t *rend_query)
{
int ret;
extend_info_t *result;
rend_cache_entry_t *entry;
ret = rend_cache_lookup_entry(rend_query->onion_address, -1, &entry);
if (ret < 0 || !rend_client_any_intro_points_usable(entry)) {
log_warn(LD_REND,
"Query '%s' didn't have valid rend desc in cache. Failing.",
safe_str_client(rend_query->onion_address));
/* XXX: Should we refetch the descriptor here if the IPs are not usable
* anymore ?. */
return NULL;
}
/* See if we can get a node that complies with ExcludeNodes */
if ((result = rend_client_get_random_intro_impl(entry, 1, 1)))
return result;
/* If not, and StrictNodes is not set, see if we can return any old node
*/
if (!get_options()->StrictNodes)
return rend_client_get_random_intro_impl(entry, 0, 1);
return NULL;
}
/** As rend_client_get_random_intro, except assume that StrictNodes is set
* iff <b>strict</b> is true. If <b>warnings</b> is false, don't complain
* to the user when we're out of nodes, even if StrictNodes is true.
*/
static extend_info_t *
rend_client_get_random_intro_impl(const rend_cache_entry_t *entry,
const int strict,
const int warnings)
{
int i;
rend_intro_point_t *intro;
const or_options_t *options = get_options();
smartlist_t *usable_nodes;
int n_excluded = 0;
/* We'll keep a separate list of the usable nodes. If this becomes empty,
* no nodes are usable. */
usable_nodes = smartlist_new();
smartlist_add_all(usable_nodes, entry->parsed->intro_nodes);
/* Remove the intro points that have timed out during this HS
* connection attempt from our list of usable nodes. */
SMARTLIST_FOREACH(usable_nodes, rend_intro_point_t *, ip,
if (ip->timed_out) {
SMARTLIST_DEL_CURRENT(usable_nodes, ip);
});
again:
if (smartlist_len(usable_nodes) == 0) {
if (n_excluded && get_options()->StrictNodes && warnings) {
/* We only want to warn if StrictNodes is really set. Otherwise
* we're just about to retry anyways.
*/
log_warn(LD_REND, "All introduction points for hidden service are "
"at excluded relays, and StrictNodes is set. Skipping.");
}
smartlist_free(usable_nodes);
return NULL;
}
i = crypto_rand_int(smartlist_len(usable_nodes));
intro = smartlist_get(usable_nodes, i);
if (BUG(!intro->extend_info)) {
/* This should never happen, but it isn't fatal, just try another */
smartlist_del(usable_nodes, i);
goto again;
}
/* All version 2 HS descriptors come with a TAP onion key.
* Clients used to try to get the TAP onion key from the consensus, but this
* meant that hidden services could discover which consensus clients have. */
if (!extend_info_supports_tap(intro->extend_info)) {
log_info(LD_REND, "The HS descriptor is missing a TAP onion key for the "
"intro-point relay '%s'; trying another.",
safe_str_client(extend_info_describe(intro->extend_info)));
smartlist_del(usable_nodes, i);
goto again;
}
/* Check if we should refuse to talk to this router. */
if (strict &&
routerset_contains_extendinfo(options->ExcludeNodes,
intro->extend_info)) {
n_excluded++;
smartlist_del(usable_nodes, i);
goto again;
}
smartlist_free(usable_nodes);
return extend_info_dup(intro->extend_info);
}
/** Return true iff any introduction points still listed in <b>entry</b> are
* usable. */
int
rend_client_any_intro_points_usable(const rend_cache_entry_t *entry)
{
extend_info_t *extend_info =
rend_client_get_random_intro_impl(entry, get_options()->StrictNodes, 0);
int rv = (extend_info != NULL);
extend_info_free(extend_info);
return rv;
}
/** Client-side authorizations for hidden services; map of onion address to
* rend_service_authorization_t*. */
static strmap_t *auth_hid_servs = NULL;
/** Look up the client-side authorization for the hidden service with
* <b>onion_address</b>. Return NULL if no authorization is available for
* that address. */
rend_service_authorization_t*
rend_client_lookup_service_authorization(const char *onion_address)
{
tor_assert(onion_address);
if (!auth_hid_servs) return NULL;
return strmap_get(auth_hid_servs, onion_address);
}
/** Helper: Free storage held by rend_service_authorization_t. */
static void
rend_service_authorization_free(rend_service_authorization_t *auth)
{
tor_free(auth);
}
/** Helper for strmap_free. */
static void
rend_service_authorization_strmap_item_free(void *service_auth)
{
rend_service_authorization_free(service_auth);
}
/** Release all the storage held in auth_hid_servs.
*/
void
rend_service_authorization_free_all(void)
{
if (!auth_hid_servs) {
return;
}
strmap_free(auth_hid_servs, rend_service_authorization_strmap_item_free);
auth_hid_servs = NULL;
}
/** Parse <b>config_line</b> as a client-side authorization for a hidden
* service and add it to the local map of hidden service authorizations.
* Return 0 for success and -1 for failure. */
int
rend_parse_service_authorization(const or_options_t *options,
int validate_only)
{
config_line_t *line;
int res = -1;
strmap_t *parsed = strmap_new();
smartlist_t *sl = smartlist_new();
rend_service_authorization_t *auth = NULL;
char *err_msg = NULL;
for (line = options->HidServAuth; line; line = line->next) {
char *onion_address, *descriptor_cookie;
auth = NULL;
SMARTLIST_FOREACH(sl, char *, c, tor_free(c););
smartlist_clear(sl);
smartlist_split_string(sl, line->value, " ",
SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 3);
if (smartlist_len(sl) < 2) {
log_warn(LD_CONFIG, "Configuration line does not consist of "
"\"onion-address authorization-cookie [service-name]\": "
"'%s'", line->value);
goto err;
}
auth = tor_malloc_zero(sizeof(rend_service_authorization_t));
/* Parse onion address. */
onion_address = smartlist_get(sl, 0);
if (strlen(onion_address) != REND_SERVICE_ADDRESS_LEN ||
strcmpend(onion_address, ".onion")) {
log_warn(LD_CONFIG, "Onion address has wrong format: '%s'",
onion_address);
goto err;
}
strlcpy(auth->onion_address, onion_address, REND_SERVICE_ID_LEN_BASE32+1);
if (!rend_valid_service_id(auth->onion_address)) {
log_warn(LD_CONFIG, "Onion address has wrong format: '%s'",
onion_address);
goto err;
}
/* Parse descriptor cookie. */
descriptor_cookie = smartlist_get(sl, 1);
if (rend_auth_decode_cookie(descriptor_cookie, auth->descriptor_cookie,
&auth->auth_type, &err_msg) < 0) {
tor_assert(err_msg);
log_warn(LD_CONFIG, "%s", err_msg);
tor_free(err_msg);
goto err;
}
if (strmap_get(parsed, auth->onion_address)) {
log_warn(LD_CONFIG, "Duplicate authorization for the same hidden "
"service.");
goto err;
}
strmap_set(parsed, auth->onion_address, auth);
auth = NULL;
}
res = 0;
goto done;
err:
res = -1;
done:
rend_service_authorization_free(auth);
SMARTLIST_FOREACH(sl, char *, c, tor_free(c););
smartlist_free(sl);
if (!validate_only && res == 0) {
rend_service_authorization_free_all();
auth_hid_servs = parsed;
} else {
strmap_free(parsed, rend_service_authorization_strmap_item_free);
}
return res;
}
/* Can Tor client code make direct (non-anonymous) connections to introduction
* or rendezvous points?
* Returns true if tor was compiled with NON_ANONYMOUS_MODE_ENABLED, and is
* configured in Tor2web mode. */
int
rend_client_allow_non_anonymous_connection(const or_options_t *options)
{
/* Tor2web support needs to be compiled in to a tor binary. */
#ifdef NON_ANONYMOUS_MODE_ENABLED
/* Tor2web */
return options->Tor2webMode ? 1 : 0;
#else
(void)options;
return 0;
#endif
}
/* At compile-time, was non-anonymous mode enabled via
* NON_ANONYMOUS_MODE_ENABLED ? */
int
rend_client_non_anonymous_mode_enabled(const or_options_t *options)
{
(void)options;
/* Tor2web support needs to be compiled in to a tor binary. */
#ifdef NON_ANONYMOUS_MODE_ENABLED
/* Tor2web */
return 1;
#else
return 0;
#endif
}
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