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tor/src/or/rendclient.c

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/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2011, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file rendclient.c
* \brief Client code to access location-hidden services.
**/
#include "or.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 "relay.h"
#include "rendclient.h"
#include "rendcommon.h"
#include "rephist.h"
#include "routerlist.h"
/** 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();
}
/** 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");
if (crypto_rand(circ->rend_data->rend_cookie, REND_COOKIE_LEN) < 0) {
log_warn(LD_BUG, "Internal error: Couldn't produce random cookie.");
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL);
return -1;
}
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;
}
/** 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)
{
size_t payload_len;
int r, v3_shift = 0;
char payload[RELAY_PAYLOAD_SIZE];
char tmp[RELAY_PAYLOAD_SIZE];
rend_cache_entry_t *entry;
crypt_path_t *cpath;
off_t dh_offset;
crypto_pk_env_t *intro_key = NULL;
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));
if (rend_cache_lookup_entry(introcirc->rend_data->onion_address, -1,
&entry) < 1) {
log_warn(LD_REND,
"query %s didn't have valid rend desc in cache. Failing.",
escaped_safe_str_client(introcirc->rend_data->onion_address));
goto err;
}
/* first 20 bytes of payload are the hash of the intro key */
intro_key = NULL;
SMARTLIST_FOREACH(entry->parsed->intro_nodes, rend_intro_point_t *,
intro, {
if (!memcmp(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, "Our introduction point knowledge changed in "
"mid-connect! Could not find intro key; we only have a "
"v2 rend desc with %d intro points. Giving up.",
smartlist_len(entry->parsed->intro_nodes));
goto err;
}
if (crypto_pk_get_digest(intro_key, payload)<0) {
log_warn(LD_BUG, "Internal error: couldn't hash public key.");
goto 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->dh_handshake_state = crypto_dh_new())) {
log_warn(LD_BUG, "Internal error: couldn't allocate DH.");
goto err;
}
if (crypto_dh_generate_public(cpath->dh_handshake_state)<0) {
log_warn(LD_BUG, "Internal error: couldn't generate g^x.");
goto 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;
}
set_uint32(tmp+v3_shift+1, htonl((uint32_t)time(NULL)));
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_ipv4h(&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->dh_handshake_state, tmp+dh_offset,
DH_KEY_LEN)<0) {
log_warn(LD_BUG, "Internal error: couldn't extract g^x.");
goto 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.");
goto err;
}
payload_len = DIGEST_LEN + r;
tor_assert(payload_len <= RELAY_PAYLOAD_SIZE); /* we overran something */
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");
return -1;
}
/* Now, we wait for an ACK or NAK on this circuit. */
introcirc->_base.purpose = CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT;
return 0;
err:
circuit_mark_for_close(TO_CIRCUIT(introcirc), END_CIRC_REASON_INTERNAL);
circuit_mark_for_close(TO_CIRCUIT(rendcirc), END_CIRC_REASON_INTERNAL);
return -1;
}
/** 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 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)
{
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 %d.",
circ->_base.n_circ_id);
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
return -1;
}
tor_assert(circ->build_state->chosen_exit);
tor_assert(circ->rend_data);
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_by_rend_query_and_purpose(
circ->rend_data->onion_address, CIRCUIT_PURPOSE_C_REND_READY);
if (rendcirc) { /* remember the ack */
rendcirc->_base.purpose = CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED;
} else {
log_info(LD_REND,"...Found no rend circ. Dropping on the floor.");
}
/* close the circuit: we won't need it anymore. */
circ->_base.purpose = CIRCUIT_PURPOSE_C_INTRODUCE_ACKED;
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED);
} else {
/* It's a NAK; the introduction point didn't relay our request. */
circ->_base.purpose = 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.
*/
if (rend_client_remove_intro_point(circ->build_state->chosen_exit,
circ->rend_data) > 0) {
/* There are introduction points left. Re-extend the circuit to
* another intro point and try again. */
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 introduction points left for %s. Closing.",
escaped_safe_str_client(circ->rend_data->onion_address));
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_INTERNAL);
return -1;
}
if (circ->remaining_relay_early_cells) {
log_info(LD_REND,
"Got nack for %s from %s. Re-extending circ %d, "
"this time to %s.",
escaped_safe_str_client(circ->rend_data->onion_address),
circ->build_state->chosen_exit->nickname,
circ->_base.n_circ_id, extend_info->nickname);
result = circuit_extend_to_new_exit(circ, extend_info);
} else {
log_info(LD_REND,
"Got nack for %s from %s. Building a new introduction "
"circuit, this time to %s.",
escaped_safe_str_client(circ->rend_data->onion_address),
circ->build_state->chosen_exit->nickname,
extend_info->nickname);
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_FINISHED);
if (!circuit_launch_by_extend_info(CIRCUIT_PURPOSE_C_INTRODUCING,
extend_info,
CIRCLAUNCH_IS_INTERNAL)) {
log_warn(LD_REND, "Building introduction circuit failed.");
result = -1;
} else {
result = 0;
}
}
extend_info_free(extend_info);
return result;
}
}
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)
/** Contains the last request times to hidden service directories for
* certain queries; keys are strings consisting of base32-encoded
* hidden service directory identities and base32-encoded descriptor IDs;
* values are pointers to timestamps of the last requests. */
static strmap_t *last_hid_serv_requests = NULL;
/** 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[2 * REND_DESC_ID_V2_LEN_BASE32 + 1];
time_t *last_request_ptr;
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);
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(void)
{
strmap_iter_t *iter;
time_t cutoff = time(NULL) - REND_HID_SERV_DIR_REQUERY_PERIOD;
if (!last_hid_serv_requests)
last_hid_serv_requests = strmap_new();
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);
}
}
}
/** Determine the responsible hidden service directories for <b>desc_id</b>
* and fetch the descriptor belonging to that ID from one of them. Only
* send a request to hidden service directories that we did not try within
* the last REND_HID_SERV_DIR_REQUERY_PERIOD seconds; 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. <b>query</b> is only
* passed for pretty log statements. */
static int
directory_get_from_hs_dir(const char *desc_id, const rend_data_t *rend_query)
{
smartlist_t *responsible_dirs = smartlist_create();
routerstatus_t *hs_dir;
char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
time_t now = time(NULL);
char descriptor_cookie_base64[3*REND_DESC_COOKIE_LEN_BASE64];
tor_assert(desc_id);
tor_assert(rend_query);
/* 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. */
(int) hid_serv_get_responsible_directories(responsible_dirs, desc_id);
base32_encode(desc_id_base32, sizeof(desc_id_base32),
desc_id, DIGEST_LEN);
/* Only select those hidden service directories to which we did not send
* a request recently and for which we have a router descriptor here. */
directory_clean_last_hid_serv_requests(); /* Clean request history first. */
SMARTLIST_FOREACH(responsible_dirs, routerstatus_t *, dir, {
if (lookup_last_hid_serv_request(dir, desc_id_base32, 0, 0) +
REND_HID_SERV_DIR_REQUERY_PERIOD >= now ||
!router_get_by_digest(dir->identity_digest))
SMARTLIST_DEL_CURRENT(responsible_dirs, dir);
});
hs_dir = smartlist_choose(responsible_dirs);
smartlist_free(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.");
return 0;
}
/* 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);
/* Encode descriptor cookie for logging purposes. */
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) {
log_warn(LD_BUG, "Could not base64-encode descriptor cookie.");
return 0;
}
/* Remove == signs and newline. */
descriptor_cookie_base64[strlen(descriptor_cookie_base64)-3] = '\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,
1, 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' on port %d.",
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)),
hs_dir->nickname, hs_dir->dir_port);
return 1;
}
/** 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(const rend_data_t *rend_query)
{
char descriptor_id[DIGEST_LEN];
int replicas_left_to_try[REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS];
int i, tries_left;
rend_cache_entry_t *e = NULL;
tor_assert(rend_query);
/* 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;
}
/* Before fetching, check if we already have the descriptor here. */
if (rend_cache_lookup_entry(rend_query->onion_address, -1, &e) > 0) {
log_info(LD_REND, "We would fetch a v2 rendezvous descriptor, but we "
"already have that descriptor here. Not fetching.");
return;
}
log_debug(LD_REND, "Fetching v2 rendezvous descriptor for service %s",
safe_str_client(rend_query->onion_address));
/* Randomly iterate over the replicas until a descriptor can be fetched
* from one of the consecutive nodes, or no options are left. */
tries_left = REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS;
for (i = 0; i < REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS; i++)
replicas_left_to_try[i] = i;
while (tries_left > 0) {
int rand = crypto_rand_int(tries_left);
int chosen_replica = replicas_left_to_try[rand];
replicas_left_to_try[rand] = replicas_left_to_try[--tries_left];
if (rend_compute_v2_desc_id(descriptor_id, rend_query->onion_address,
rend_query->auth_type == REND_STEALTH_AUTH ?
rend_query->descriptor_cookie : NULL,
time(NULL), chosen_replica) < 0) {
log_warn(LD_REND, "Internal error: Computing v2 rendezvous "
"descriptor ID did not succeed.");
return;
}
if (directory_get_from_hs_dir(descriptor_id, rend_query) != 0)
return; /* either success or failure, but we're done */
}
/* 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.");
/* Close pending connections. */
rend_client_desc_trynow(rend_query->onion_address);
return;
}
/** Remove failed_intro from ent. If ent now has no intro points, or
* service is unrecognized, then launch a new renddesc fetch.
*
* Return -1 if error, 0 if no intro points remain or service
* unrecognized, 1 if recognized and some intro points remain.
*/
int
rend_client_remove_intro_point(extend_info_t *failed_intro,
const rend_data_t *rend_query)
{
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) {
log_warn(LD_BUG, "Malformed service ID %s.",
escaped_safe_str_client(rend_query->onion_address));
return -1;
}
if (r==0) {
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;
}
for (i = 0; i < smartlist_len(ent->parsed->intro_nodes); i++) {
rend_intro_point_t *intro = smartlist_get(ent->parsed->intro_nodes, i);
if (!memcmp(failed_intro->identity_digest,
intro->extend_info->identity_digest, DIGEST_LEN)) {
rend_intro_point_free(intro);
smartlist_del(ent->parsed->intro_nodes, i);
break;
}
}
if (smartlist_len(ent->parsed->intro_nodes) == 0) {
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 */
while ((conn = connection_get_by_type_state_rendquery(CONN_TYPE_AP,
AP_CONN_STATE_CIRCUIT_WAIT,
rend_query->onion_address))) {
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.");
circ->_base.purpose = CIRCUIT_PURPOSE_C_REND_READY;
/* XXXX022 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();
return 0;
}
/** Bob 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 bob. 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->dh_handshake_state);
if (crypto_dh_compute_secret(LOG_PROTOCOL_WARN,
hop->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 (memcmp(keys, request+DH_KEY_LEN, DIGEST_LEN)) {
log_warn(LD_PROTOCOL, "Incorrect digest of key material.");
goto err;
}
crypto_dh_free(hop->dh_handshake_state);
hop->dh_handshake_state = NULL;
/* All is well. Extend the circuit. */
circ->_base.purpose = CIRCUIT_PURPOSE_C_REND_JOINED;
hop->state = CPATH_STATE_OPEN;
/* set the windows to default. these are the windows
* that alice thinks bob has.
*/
hop->package_window = circuit_initial_package_window();
hop->deliver_window = CIRCWINDOW_START;
onion_append_to_cpath(&circ->cpath, hop);
circ->build_state->pending_final_cpath = NULL; /* prevent double-free */
/* XXXX022 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. */
connection_ap_attach_pending();
memset(keys, 0, sizeof(keys));
return 0;
err:
memset(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)
{
edge_connection_t *conn;
rend_cache_entry_t *entry;
time_t now = time(NULL);
smartlist_t *conns = get_connection_array();
SMARTLIST_FOREACH_BEGIN(conns, connection_t *, _conn) {
if (_conn->type != CONN_TYPE_AP ||
_conn->state != AP_CONN_STATE_RENDDESC_WAIT ||
_conn->marked_for_close)
continue;
conn = TO_EDGE_CONN(_conn);
if (!conn->rend_data)
continue;
if (rend_cmp_service_ids(query, conn->rend_data->onion_address))
continue;
assert_connection_ok(TO_CONN(conn), now);
if (rend_cache_lookup_entry(conn->rend_data->onion_address, -1,
&entry) == 1 &&
smartlist_len(entry->parsed->intro_nodes) > 0) {
/* 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.");
conn->_base.state = AP_CONN_STATE_CIRCUIT_WAIT;
/* restart their timeout values, so they get a fair shake at
* connecting to the hidden service. */
conn->_base.timestamp_created = now;
conn->_base.timestamp_lastread = now;
conn->_base.timestamp_lastwritten = now;
if (connection_ap_handshake_attach_circuit(conn) < 0) {
/* it will never work */
log_warn(LD_REND,"Rendezvous attempt failed. Closing.");
if (!conn->_base.marked_for_close)
connection_mark_unattached_ap(conn, END_STREAM_REASON_CANT_ATTACH);
}
} 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);
}
} SMARTLIST_FOREACH_END(_conn);
}
/** 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 i;
rend_cache_entry_t *entry;
rend_intro_point_t *intro;
routerinfo_t *router;
if (rend_cache_lookup_entry(rend_query->onion_address, -1, &entry) < 1) {
log_warn(LD_REND,
"Query '%s' didn't have valid rend desc in cache. Failing.",
safe_str_client(rend_query->onion_address));
return NULL;
}
again:
if (smartlist_len(entry->parsed->intro_nodes) == 0)
return NULL;
i = crypto_rand_int(smartlist_len(entry->parsed->intro_nodes));
intro = smartlist_get(entry->parsed->intro_nodes, i);
/* Do we need to look up the router or is the extend info complete? */
if (!intro->extend_info->onion_key) {
if (tor_digest_is_zero(intro->extend_info->identity_digest))
router = router_get_by_hexdigest(intro->extend_info->nickname);
else
router = router_get_by_digest(intro->extend_info->identity_digest);
if (!router) {
log_info(LD_REND, "Unknown router with nickname '%s'; trying another.",
intro->extend_info->nickname);
rend_intro_point_free(intro);
smartlist_del(entry->parsed->intro_nodes, i);
goto again;
}
extend_info_free(intro->extend_info);
intro->extend_info = extend_info_from_router(router);
}
return extend_info_dup(intro->extend_info);
}
/** 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(or_options_t *options, int validate_only)
{
config_line_t *line;
int res = -1;
strmap_t *parsed = strmap_new();
smartlist_t *sl = smartlist_create();
rend_service_authorization_t *auth = NULL;
for (line = options->HidServAuth; line; line = line->next) {
char *onion_address, *descriptor_cookie;
char descriptor_cookie_tmp[REND_DESC_COOKIE_LEN+2];
char descriptor_cookie_base64ext[REND_DESC_COOKIE_LEN_BASE64+2+1];
int auth_type_val = 0;
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 (strlen(descriptor_cookie) != REND_DESC_COOKIE_LEN_BASE64) {
log_warn(LD_CONFIG, "Authorization cookie has wrong length: '%s'",
descriptor_cookie);
goto err;
}
/* Add trailing zero bytes (AA) to make base64-decoding happy. */
tor_snprintf(descriptor_cookie_base64ext,
REND_DESC_COOKIE_LEN_BASE64+2+1,
"%sAA", descriptor_cookie);
if (base64_decode(descriptor_cookie_tmp, sizeof(descriptor_cookie_tmp),
descriptor_cookie_base64ext,
strlen(descriptor_cookie_base64ext)) < 0) {
log_warn(LD_CONFIG, "Decoding authorization cookie failed: '%s'",
descriptor_cookie);
goto err;
}
auth_type_val = (descriptor_cookie_tmp[16] >> 4) + 1;
if (auth_type_val < 1 || auth_type_val > 2) {
log_warn(LD_CONFIG, "Authorization cookie has unknown authorization "
"type encoded.");
goto err;
}
auth->auth_type = auth_type_val == 1 ? REND_BASIC_AUTH : REND_STEALTH_AUTH;
memcpy(auth->descriptor_cookie, descriptor_cookie_tmp,
REND_DESC_COOKIE_LEN);
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;
}
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