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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
**/
#include "or.h"
#include "hs_circuit.h"
#include "hs_ident.h"
#include "connection_edge.h"
#include "rendclient.h"
#include "hs_descriptor.h"
#include "hs_cache.h"
#include "config.h"
#include "directory.h"
#include "hs_client.h"
#include "router.h"
/* 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)
{
(void) hs_conn_ident;
/* TODO: When implementing client side */
return;
}
/* 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 1 on
* success or -1 on error. */
static int
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(approx_time());
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 -1;
}
/* Copy onion pk to a dir_ident so that we attach it to the dir conn */
ed25519_pubkey_copy(&hs_conn_dir_ident.identity_pk, onion_identity_pk);
/* 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_upload_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 1;
}
/** 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(approx_time());
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, 1 is returned. If no hidden service is left to ask, return 0.
* On error, -1 is returned. */
static int
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 0;
}
return directory_launch_v3_desc_fetch(onion_identity_pk, hsdir_rs);
}
/** 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];
tor_assert(desc_str);
tor_assert(service_identity_pk);
tor_assert(desc);
/* Create subcredential for this HS so that we can decrypt */
{
ed25519_public_key_t blinded_pubkey;
uint64_t current_time_period = hs_get_time_period_num(approx_time());
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");
goto err;
}
return 0;
err:
return -1;
}
/** Return true if there are any usable intro points in the v3 HS descriptor
* <b>desc</b>. */
int
hs_client_any_intro_points_usable(const hs_descriptor_t *desc)
{
/* XXX stub waiting for more client-side work:
equivalent to v2 rend_client_any_intro_points_usable() */
tor_assert(desc);
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.
*
* On success, 1 is returned. If no hidden service is left to ask, return 0.
* On error, -1 is returned. (retval is only used by unittests right now) */
int
hs_client_refetch_hsdesc(const ed25519_public_key_t *identity_pk)
{
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.");
return 0;
}
/* 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(cached_desc)) {
log_warn(LD_GENERAL, "We would fetch a v3 hidden service descriptor "
"but we already have a useable descriprot.");
return 0;
}
}
return fetch_v3_desc(identity_pk);
}
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