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tor/src/feature/rend/rendcommon.c

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/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2018, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file rendcommon.c
* \brief Rendezvous implementation: shared code between
* introducers, services, clients, and rendezvous points.
**/
#define RENDCOMMON_PRIVATE
#include "core/or/or.h"
#include "core/or/circuitbuild.h"
#include "core/or/circuitlist.h"
#include "core/or/circuituse.h"
#include "app/config/config.h"
#include "feature/control/control.h"
#include "lib/crypt_ops/crypto_rand.h"
#include "lib/crypt_ops/crypto_util.h"
#include "feature/hs/hs_client.h"
#include "feature/hs/hs_common.h"
#include "feature/hs/hs_intropoint.h"
#include "feature/nodelist/networkstatus.h"
#include "feature/rend/rendclient.h"
#include "feature/rend/rendcommon.h"
#include "feature/rend/rendmid.h"
#include "feature/rend/rendparse.h"
#include "feature/rend/rendservice.h"
#include "feature/stats/rephist.h"
#include "feature/hs_common/replaycache.h"
#include "feature/relay/router.h"
#include "feature/nodelist/routerlist.h"
#include "feature/dirparse/signing.h"
#include "core/or/cpath_build_state_st.h"
#include "core/or/crypt_path_st.h"
#include "core/or/extend_info_st.h"
#include "feature/nodelist/networkstatus_st.h"
#include "core/or/origin_circuit_st.h"
#include "feature/rend/rend_encoded_v2_service_descriptor_st.h"
#include "feature/rend/rend_intro_point_st.h"
#include "feature/rend/rend_service_descriptor_st.h"
#include "feature/nodelist/routerstatus_st.h"
/** Return 0 if one and two are the same service ids, else -1 or 1 */
int
rend_cmp_service_ids(const char *one, const char *two)
{
return strcasecmp(one,two);
}
/** Free the storage held by the service descriptor <b>desc</b>.
*/
void
rend_service_descriptor_free_(rend_service_descriptor_t *desc)
{
if (!desc)
return;
if (desc->pk)
crypto_pk_free(desc->pk);
if (desc->intro_nodes) {
SMARTLIST_FOREACH(desc->intro_nodes, rend_intro_point_t *, intro,
rend_intro_point_free(intro););
smartlist_free(desc->intro_nodes);
}
if (desc->successful_uploads) {
SMARTLIST_FOREACH(desc->successful_uploads, char *, c, tor_free(c););
smartlist_free(desc->successful_uploads);
}
tor_free(desc);
}
/** Length of the descriptor cookie that is used for versioned hidden
* service descriptors. */
#define REND_DESC_COOKIE_LEN 16
/** Length of the replica number that is used to determine the secret ID
* part of versioned hidden service descriptors. */
#define REND_REPLICA_LEN 1
/** Compute the descriptor ID for <b>service_id</b> of length
* <b>REND_SERVICE_ID_LEN</b> and <b>secret_id_part</b> of length
* <b>DIGEST_LEN</b>, and write it to <b>descriptor_id_out</b> of length
* <b>DIGEST_LEN</b>. */
void
rend_get_descriptor_id_bytes(char *descriptor_id_out,
const char *service_id,
const char *secret_id_part)
{
crypto_digest_t *digest = crypto_digest_new();
crypto_digest_add_bytes(digest, service_id, REND_SERVICE_ID_LEN);
crypto_digest_add_bytes(digest, secret_id_part, DIGEST_LEN);
crypto_digest_get_digest(digest, descriptor_id_out, DIGEST_LEN);
crypto_digest_free(digest);
}
/** Compute the secret ID part for time_period,
* a <b>descriptor_cookie</b> of length
* <b>REND_DESC_COOKIE_LEN</b> which may also be <b>NULL</b> if no
* descriptor_cookie shall be used, and <b>replica</b>, and write it to
* <b>secret_id_part</b> of length DIGEST_LEN. */
static void
get_secret_id_part_bytes(char *secret_id_part, uint32_t time_period,
const char *descriptor_cookie, uint8_t replica)
{
crypto_digest_t *digest = crypto_digest_new();
time_period = htonl(time_period);
crypto_digest_add_bytes(digest, (char*)&time_period, sizeof(uint32_t));
if (descriptor_cookie) {
crypto_digest_add_bytes(digest, descriptor_cookie,
REND_DESC_COOKIE_LEN);
}
crypto_digest_add_bytes(digest, (const char *)&replica, REND_REPLICA_LEN);
crypto_digest_get_digest(digest, secret_id_part, DIGEST_LEN);
crypto_digest_free(digest);
}
/** Return the time period for time <b>now</b> plus a potentially
* intended <b>deviation</b> of one or more periods, based on the first byte
* of <b>service_id</b>. */
static uint32_t
get_time_period(time_t now, uint8_t deviation, const char *service_id)
{
/* The time period is the number of REND_TIME_PERIOD_V2_DESC_VALIDITY
* intervals that have passed since the epoch, offset slightly so that
* each service's time periods start and end at a fraction of that
* period based on their first byte. */
return (uint32_t)
(now + ((uint8_t) *service_id) * REND_TIME_PERIOD_V2_DESC_VALIDITY / 256)
/ REND_TIME_PERIOD_V2_DESC_VALIDITY + deviation;
}
/** Compute the time in seconds that a descriptor that is generated
* <b>now</b> for <b>service_id</b> will be valid. */
static uint32_t
get_seconds_valid(time_t now, const char *service_id)
{
uint32_t result = REND_TIME_PERIOD_V2_DESC_VALIDITY -
((uint32_t)
(now + ((uint8_t) *service_id) * REND_TIME_PERIOD_V2_DESC_VALIDITY / 256)
% REND_TIME_PERIOD_V2_DESC_VALIDITY);
return result;
}
/** Compute the binary <b>desc_id_out</b> (DIGEST_LEN bytes long) for a given
* base32-encoded <b>service_id</b> and optional unencoded
* <b>descriptor_cookie</b> of length REND_DESC_COOKIE_LEN,
* at time <b>now</b> for replica number
* <b>replica</b>. <b>desc_id</b> needs to have <b>DIGEST_LEN</b> bytes
* free. Return 0 for success, -1 otherwise. */
int
rend_compute_v2_desc_id(char *desc_id_out, const char *service_id,
const char *descriptor_cookie, time_t now,
uint8_t replica)
{
char service_id_binary[REND_SERVICE_ID_LEN];
char secret_id_part[DIGEST_LEN];
uint32_t time_period;
if (!service_id ||
strlen(service_id) != REND_SERVICE_ID_LEN_BASE32) {
log_warn(LD_REND, "Could not compute v2 descriptor ID: "
"Illegal service ID: %s",
safe_str(service_id));
return -1;
}
if (replica >= REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS) {
log_warn(LD_REND, "Could not compute v2 descriptor ID: "
"Replica number out of range: %d", replica);
return -1;
}
/* Convert service ID to binary. */
if (base32_decode(service_id_binary, REND_SERVICE_ID_LEN,
service_id, REND_SERVICE_ID_LEN_BASE32) < 0) {
log_warn(LD_REND, "Could not compute v2 descriptor ID: "
"Illegal characters in service ID: %s",
safe_str_client(service_id));
return -1;
}
/* Calculate current time-period. */
time_period = get_time_period(now, 0, service_id_binary);
/* Calculate secret-id-part = h(time-period | desc-cookie | replica). */
get_secret_id_part_bytes(secret_id_part, time_period, descriptor_cookie,
replica);
/* Calculate descriptor ID: H(permanent-id | secret-id-part) */
rend_get_descriptor_id_bytes(desc_id_out, service_id_binary, secret_id_part);
return 0;
}
/** Encode the introduction points in <b>desc</b> and write the result to a
* newly allocated string pointed to by <b>encoded</b>. Return 0 for
* success, -1 otherwise. */
static int
rend_encode_v2_intro_points(char **encoded, rend_service_descriptor_t *desc)
{
size_t unenc_len;
char *unenc = NULL;
size_t unenc_written = 0;
int i;
int r = -1;
/* Assemble unencrypted list of introduction points. */
unenc_len = smartlist_len(desc->intro_nodes) * 1000; /* too long, but ok. */
unenc = tor_malloc_zero(unenc_len);
for (i = 0; i < smartlist_len(desc->intro_nodes); i++) {
char id_base32[REND_INTRO_POINT_ID_LEN_BASE32 + 1];
char *onion_key = NULL;
size_t onion_key_len;
crypto_pk_t *intro_key;
char *service_key = NULL;
char *address = NULL;
size_t service_key_len;
int res;
rend_intro_point_t *intro = smartlist_get(desc->intro_nodes, i);
/* Obtain extend info with introduction point details. */
extend_info_t *info = intro->extend_info;
/* Encode introduction point ID. */
base32_encode(id_base32, sizeof(id_base32),
info->identity_digest, DIGEST_LEN);
/* Encode onion key. */
if (crypto_pk_write_public_key_to_string(info->onion_key, &onion_key,
&onion_key_len) < 0) {
log_warn(LD_REND, "Could not write onion key.");
goto done;
}
/* Encode intro key. */
intro_key = intro->intro_key;
if (!intro_key ||
crypto_pk_write_public_key_to_string(intro_key, &service_key,
&service_key_len) < 0) {
log_warn(LD_REND, "Could not write intro key.");
tor_free(onion_key);
goto done;
}
/* Assemble everything for this introduction point. */
address = tor_addr_to_str_dup(&info->addr);
res = tor_snprintf(unenc + unenc_written, unenc_len - unenc_written,
"introduction-point %s\n"
"ip-address %s\n"
"onion-port %d\n"
"onion-key\n%s"
"service-key\n%s",
id_base32,
address,
info->port,
onion_key,
service_key);
tor_free(address);
tor_free(onion_key);
tor_free(service_key);
if (res < 0) {
log_warn(LD_REND, "Not enough space for writing introduction point "
"string.");
goto done;
}
/* Update total number of written bytes for unencrypted intro points. */
unenc_written += res;
}
/* Finalize unencrypted introduction points. */
if (unenc_len < unenc_written + 2) {
log_warn(LD_REND, "Not enough space for finalizing introduction point "
"string.");
goto done;
}
unenc[unenc_written++] = '\n';
unenc[unenc_written++] = 0;
*encoded = unenc;
r = 0;
done:
if (r<0)
tor_free(unenc);
return r;
}
/** Encrypt the encoded introduction points in <b>encoded</b> using
* authorization type 'basic' with <b>client_cookies</b> and write the
* result to a newly allocated string pointed to by <b>encrypted_out</b> of
* length <b>encrypted_len_out</b>. Return 0 for success, -1 otherwise. */
static int
rend_encrypt_v2_intro_points_basic(char **encrypted_out,
size_t *encrypted_len_out,
const char *encoded,
smartlist_t *client_cookies)
{
int r = -1, i, pos, enclen, client_blocks;
size_t len, client_entries_len;
char *enc = NULL, iv[CIPHER_IV_LEN], *client_part = NULL,
session_key[CIPHER_KEY_LEN];
smartlist_t *encrypted_session_keys = NULL;
crypto_digest_t *digest;
crypto_cipher_t *cipher;
tor_assert(encoded);
tor_assert(client_cookies && smartlist_len(client_cookies) > 0);
/* Generate session key. */
crypto_rand(session_key, CIPHER_KEY_LEN);
/* Determine length of encrypted introduction points including session
* keys. */
client_blocks = 1 + ((smartlist_len(client_cookies) - 1) /
REND_BASIC_AUTH_CLIENT_MULTIPLE);
client_entries_len = client_blocks * REND_BASIC_AUTH_CLIENT_MULTIPLE *
REND_BASIC_AUTH_CLIENT_ENTRY_LEN;
len = 2 + client_entries_len + CIPHER_IV_LEN + strlen(encoded);
if (client_blocks >= 256) {
log_warn(LD_REND, "Too many clients in introduction point string.");
goto done;
}
enc = tor_malloc_zero(len);
enc[0] = 0x01; /* type of authorization. */
enc[1] = (uint8_t)client_blocks;
/* Encrypt with random session key. */
enclen = crypto_cipher_encrypt_with_iv(session_key,
enc + 2 + client_entries_len,
CIPHER_IV_LEN + strlen(encoded), encoded, strlen(encoded));
if (enclen < 0) {
log_warn(LD_REND, "Could not encrypt introduction point string.");
goto done;
}
memcpy(iv, enc + 2 + client_entries_len, CIPHER_IV_LEN);
/* Encrypt session key for cookies, determine client IDs, and put both
* in a smartlist. */
encrypted_session_keys = smartlist_new();
SMARTLIST_FOREACH_BEGIN(client_cookies, const char *, cookie) {
client_part = tor_malloc_zero(REND_BASIC_AUTH_CLIENT_ENTRY_LEN);
/* Encrypt session key. */
cipher = crypto_cipher_new(cookie);
if (crypto_cipher_encrypt(cipher, client_part +
REND_BASIC_AUTH_CLIENT_ID_LEN,
session_key, CIPHER_KEY_LEN) < 0) {
log_warn(LD_REND, "Could not encrypt session key for client.");
crypto_cipher_free(cipher);
tor_free(client_part);
goto done;
}
crypto_cipher_free(cipher);
/* Determine client ID. */
digest = crypto_digest_new();
crypto_digest_add_bytes(digest, cookie, REND_DESC_COOKIE_LEN);
crypto_digest_add_bytes(digest, iv, CIPHER_IV_LEN);
crypto_digest_get_digest(digest, client_part,
REND_BASIC_AUTH_CLIENT_ID_LEN);
crypto_digest_free(digest);
/* Put both together. */
smartlist_add(encrypted_session_keys, client_part);
} SMARTLIST_FOREACH_END(cookie);
/* Add some fake client IDs and encrypted session keys. */
for (i = (smartlist_len(client_cookies) - 1) %
REND_BASIC_AUTH_CLIENT_MULTIPLE;
i < REND_BASIC_AUTH_CLIENT_MULTIPLE - 1; i++) {
client_part = tor_malloc_zero(REND_BASIC_AUTH_CLIENT_ENTRY_LEN);
crypto_rand(client_part, REND_BASIC_AUTH_CLIENT_ENTRY_LEN);
smartlist_add(encrypted_session_keys, client_part);
}
/* Sort smartlist and put elements in result in order. */
smartlist_sort_digests(encrypted_session_keys);
pos = 2;
SMARTLIST_FOREACH(encrypted_session_keys, const char *, entry, {
memcpy(enc + pos, entry, REND_BASIC_AUTH_CLIENT_ENTRY_LEN);
pos += REND_BASIC_AUTH_CLIENT_ENTRY_LEN;
});
*encrypted_out = enc;
*encrypted_len_out = len;
enc = NULL; /* prevent free. */
r = 0;
done:
tor_free(enc);
if (encrypted_session_keys) {
SMARTLIST_FOREACH(encrypted_session_keys, char *, d, tor_free(d););
smartlist_free(encrypted_session_keys);
}
return r;
}
/** Encrypt the encoded introduction points in <b>encoded</b> using
* authorization type 'stealth' with <b>descriptor_cookie</b> of length
* REND_DESC_COOKIE_LEN and write the result to a newly allocated string
* pointed to by <b>encrypted_out</b> of length <b>encrypted_len_out</b>.
* Return 0 for success, -1 otherwise. */
static int
rend_encrypt_v2_intro_points_stealth(char **encrypted_out,
size_t *encrypted_len_out,
const char *encoded,
const char *descriptor_cookie)
{
int r = -1, enclen;
char *enc;
tor_assert(encoded);
tor_assert(descriptor_cookie);
enc = tor_malloc_zero(1 + CIPHER_IV_LEN + strlen(encoded));
enc[0] = 0x02; /* Auth type */
enclen = crypto_cipher_encrypt_with_iv(descriptor_cookie,
enc + 1,
CIPHER_IV_LEN+strlen(encoded),
encoded, strlen(encoded));
if (enclen < 0) {
log_warn(LD_REND, "Could not encrypt introduction point string.");
goto done;
}
*encrypted_out = enc;
*encrypted_len_out = enclen;
enc = NULL; /* prevent free */
r = 0;
done:
tor_free(enc);
return r;
}
/** Attempt to parse the given <b>desc_str</b> and return true if this
* succeeds, false otherwise. */
STATIC int
rend_desc_v2_is_parsable(rend_encoded_v2_service_descriptor_t *desc)
{
rend_service_descriptor_t *test_parsed = NULL;
char test_desc_id[DIGEST_LEN];
char *test_intro_content = NULL;
size_t test_intro_size;
size_t test_encoded_size;
const char *test_next;
int res = rend_parse_v2_service_descriptor(&test_parsed, test_desc_id,
&test_intro_content,
&test_intro_size,
&test_encoded_size,
&test_next, desc->desc_str, 1);
rend_service_descriptor_free(test_parsed);
tor_free(test_intro_content);
return (res >= 0);
}
/** Free the storage held by an encoded v2 service descriptor. */
void
rend_encoded_v2_service_descriptor_free_(
rend_encoded_v2_service_descriptor_t *desc)
{
if (!desc)
return;
tor_free(desc->desc_str);
tor_free(desc);
}
/** Free the storage held by an introduction point info. */
void
rend_intro_point_free_(rend_intro_point_t *intro)
{
if (!intro)
return;
extend_info_free(intro->extend_info);
crypto_pk_free(intro->intro_key);
if (intro->accepted_intro_rsa_parts != NULL) {
replaycache_free(intro->accepted_intro_rsa_parts);
}
tor_free(intro);
}
/** Encode a set of rend_encoded_v2_service_descriptor_t's for <b>desc</b>
* at time <b>now</b> using <b>service_key</b>, depending on
* <b>auth_type</b> a <b>descriptor_cookie</b> and a list of
* <b>client_cookies</b> (which are both <b>NULL</b> if no client
* authorization is performed), and <b>period</b> (e.g. 0 for the current
* period, 1 for the next period, etc.) and add them to the existing list
* <b>descs_out</b>; return the number of seconds that the descriptors will
* be found by clients, or -1 if the encoding was not successful. */
int
rend_encode_v2_descriptors(smartlist_t *descs_out,
rend_service_descriptor_t *desc, time_t now,
uint8_t period, rend_auth_type_t auth_type,
crypto_pk_t *client_key,
smartlist_t *client_cookies)
{
char service_id[DIGEST_LEN];
char service_id_base32[REND_SERVICE_ID_LEN_BASE32+1];
uint32_t time_period;
char *ipos_base64 = NULL, *ipos = NULL, *ipos_encrypted = NULL,
*descriptor_cookie = NULL;
size_t ipos_len = 0, ipos_encrypted_len = 0;
int k;
uint32_t seconds_valid;
crypto_pk_t *service_key;
if (!desc) {
log_warn(LD_BUG, "Could not encode v2 descriptor: No desc given.");
return -1;
}
service_key = (auth_type == REND_STEALTH_AUTH) ? client_key : desc->pk;
tor_assert(service_key);
if (auth_type == REND_STEALTH_AUTH) {
descriptor_cookie = smartlist_get(client_cookies, 0);
tor_assert(descriptor_cookie);
}
/* Obtain service_id from public key. */
if (crypto_pk_get_digest(service_key, service_id) < 0) {
log_warn(LD_BUG, "Couldn't compute service key digest.");
return -1;
}
/* Calculate current time-period. */
time_period = get_time_period(now, period, service_id);
/* Determine how many seconds the descriptor will be valid. */
seconds_valid = period * REND_TIME_PERIOD_V2_DESC_VALIDITY +
get_seconds_valid(now, service_id);
/* Assemble, possibly encrypt, and encode introduction points. */
if (smartlist_len(desc->intro_nodes) > 0) {
if (rend_encode_v2_intro_points(&ipos, desc) < 0) {
log_warn(LD_REND, "Encoding of introduction points did not succeed.");
return -1;
}
switch (auth_type) {
case REND_NO_AUTH:
ipos_len = strlen(ipos);
break;
case REND_BASIC_AUTH:
if (rend_encrypt_v2_intro_points_basic(&ipos_encrypted,
&ipos_encrypted_len, ipos,
client_cookies) < 0) {
log_warn(LD_REND, "Encrypting of introduction points did not "
"succeed.");
tor_free(ipos);
return -1;
}
tor_free(ipos);
ipos = ipos_encrypted;
ipos_len = ipos_encrypted_len;
break;
case REND_STEALTH_AUTH:
if (rend_encrypt_v2_intro_points_stealth(&ipos_encrypted,
&ipos_encrypted_len, ipos,
descriptor_cookie) < 0) {
log_warn(LD_REND, "Encrypting of introduction points did not "
"succeed.");
tor_free(ipos);
return -1;
}
tor_free(ipos);
ipos = ipos_encrypted;
ipos_len = ipos_encrypted_len;
break;
default:
log_warn(LD_REND|LD_BUG, "Unrecognized authorization type %d",
(int)auth_type);
tor_free(ipos);
return -1;
}
/* Base64-encode introduction points. */
ipos_base64 = tor_calloc(ipos_len, 2);
if (base64_encode(ipos_base64, ipos_len * 2, ipos, ipos_len,
BASE64_ENCODE_MULTILINE)<0) {
log_warn(LD_REND, "Could not encode introduction point string to "
"base64. length=%d", (int)ipos_len);
tor_free(ipos_base64);
tor_free(ipos);
return -1;
}
tor_free(ipos);
}
/* Encode REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS descriptors. */
for (k = 0; k < REND_NUMBER_OF_NON_CONSECUTIVE_REPLICAS; k++) {
char secret_id_part[DIGEST_LEN];
char secret_id_part_base32[REND_SECRET_ID_PART_LEN_BASE32 + 1];
char desc_id_base32[REND_DESC_ID_V2_LEN_BASE32 + 1];
char *permanent_key = NULL;
size_t permanent_key_len;
char published[ISO_TIME_LEN+1];
int i;
char protocol_versions_string[16]; /* max len: "0,1,2,3,4,5,6,7\0" */
size_t protocol_versions_written;
size_t desc_len;
char *desc_str = NULL;
int result = 0;
size_t written = 0;
char desc_digest[DIGEST_LEN];
rend_encoded_v2_service_descriptor_t *enc =
tor_malloc_zero(sizeof(rend_encoded_v2_service_descriptor_t));
/* Calculate secret-id-part = h(time-period | cookie | replica). */
get_secret_id_part_bytes(secret_id_part, time_period, descriptor_cookie,
k);
base32_encode(secret_id_part_base32, sizeof(secret_id_part_base32),
secret_id_part, DIGEST_LEN);
/* Calculate descriptor ID. */
rend_get_descriptor_id_bytes(enc->desc_id, service_id, secret_id_part);
base32_encode(desc_id_base32, sizeof(desc_id_base32),
enc->desc_id, DIGEST_LEN);
/* PEM-encode the public key */
if (crypto_pk_write_public_key_to_string(service_key, &permanent_key,
&permanent_key_len) < 0) {
log_warn(LD_BUG, "Could not write public key to string.");
rend_encoded_v2_service_descriptor_free(enc);
goto err;
}
/* Encode timestamp. */
format_iso_time(published, desc->timestamp);
/* Write protocol-versions bitmask to comma-separated value string. */
protocol_versions_written = 0;
for (i = 0; i < 8; i++) {
if (desc->protocols & 1 << i) {
tor_snprintf(protocol_versions_string + protocol_versions_written,
16 - protocol_versions_written, "%d,", i);
protocol_versions_written += 2;
}
}
if (protocol_versions_written)
protocol_versions_string[protocol_versions_written - 1] = '\0';
else
protocol_versions_string[0]= '\0';
/* Assemble complete descriptor. */
desc_len = 2000 + smartlist_len(desc->intro_nodes) * 1000; /* far too long,
but okay.*/
enc->desc_str = desc_str = tor_malloc_zero(desc_len);
result = tor_snprintf(desc_str, desc_len,
"rendezvous-service-descriptor %s\n"
"version 2\n"
"permanent-key\n%s"
"secret-id-part %s\n"
"publication-time %s\n"
"protocol-versions %s\n",
desc_id_base32,
permanent_key,
secret_id_part_base32,
published,
protocol_versions_string);
tor_free(permanent_key);
if (result < 0) {
log_warn(LD_BUG, "Descriptor ran out of room.");
rend_encoded_v2_service_descriptor_free(enc);
goto err;
}
written = result;
/* Add introduction points. */
if (ipos_base64) {
result = tor_snprintf(desc_str + written, desc_len - written,
"introduction-points\n"
"-----BEGIN MESSAGE-----\n%s"
"-----END MESSAGE-----\n",
ipos_base64);
if (result < 0) {
log_warn(LD_BUG, "could not write introduction points.");
rend_encoded_v2_service_descriptor_free(enc);
goto err;
}
written += result;
}
/* Add signature. */
strlcpy(desc_str + written, "signature\n", desc_len - written);
written += strlen(desc_str + written);
if (crypto_digest(desc_digest, desc_str, written) < 0) {
log_warn(LD_BUG, "could not create digest.");
rend_encoded_v2_service_descriptor_free(enc);
goto err;
}
if (router_append_dirobj_signature(desc_str + written,
desc_len - written,
desc_digest, DIGEST_LEN,
service_key) < 0) {
log_warn(LD_BUG, "Couldn't sign desc.");
rend_encoded_v2_service_descriptor_free(enc);
goto err;
}
written += strlen(desc_str+written);
if (written+2 > desc_len) {
log_warn(LD_BUG, "Could not finish desc.");
rend_encoded_v2_service_descriptor_free(enc);
goto err;
}
desc_str[written++] = 0;
/* Check if we can parse our own descriptor. */
if (!rend_desc_v2_is_parsable(enc)) {
log_warn(LD_BUG, "Could not parse my own descriptor: %s", desc_str);
rend_encoded_v2_service_descriptor_free(enc);
goto err;
}
smartlist_add(descs_out, enc);
/* Add the uploaded descriptor to the local service's descriptor cache */
rend_cache_store_v2_desc_as_service(enc->desc_str);
base32_encode(service_id_base32, sizeof(service_id_base32),
service_id, REND_SERVICE_ID_LEN);
control_event_hs_descriptor_created(service_id_base32, desc_id_base32, k);
}
log_info(LD_REND, "Successfully encoded a v2 descriptor and "
"confirmed that it is parsable.");
goto done;
err:
SMARTLIST_FOREACH(descs_out, rend_encoded_v2_service_descriptor_t *, d,
rend_encoded_v2_service_descriptor_free(d););
smartlist_clear(descs_out);
seconds_valid = -1;
done:
tor_free(ipos_base64);
return seconds_valid;
}
/** Sets <b>out</b> to the first 10 bytes of the digest of <b>pk</b>,
* base32 encoded. NUL-terminates out. (We use this string to
* identify services in directory requests and .onion URLs.)
*/
int
rend_get_service_id(crypto_pk_t *pk, char *out)
{
char buf[DIGEST_LEN];
tor_assert(pk);
if (crypto_pk_get_digest(pk, buf) < 0)
return -1;
base32_encode(out, REND_SERVICE_ID_LEN_BASE32+1, buf, REND_SERVICE_ID_LEN);
return 0;
}
/** Return true iff <b>query</b> is a syntactically valid service ID (as
* generated by rend_get_service_id). */
int
rend_valid_v2_service_id(const char *query)
{
if (strlen(query) != REND_SERVICE_ID_LEN_BASE32)
return 0;
if (strspn(query, BASE32_CHARS) != REND_SERVICE_ID_LEN_BASE32)
return 0;
return 1;
}
/** Return true iff <b>query</b> is a syntactically valid descriptor ID.
* (as generated by rend_get_descriptor_id_bytes). */
int
rend_valid_descriptor_id(const char *query)
{
if (strlen(query) != REND_DESC_ID_V2_LEN_BASE32) {
goto invalid;
}
if (strspn(query, BASE32_CHARS) != REND_DESC_ID_V2_LEN_BASE32) {
goto invalid;
}
return 1;
invalid:
return 0;
}
/** Return true iff <b>client_name</b> is a syntactically valid name
* for rendezvous client authentication. */
int
rend_valid_client_name(const char *client_name)
{
size_t len = strlen(client_name);
if (len < 1 || len > REND_CLIENTNAME_MAX_LEN) {
return 0;
}
if (strspn(client_name, REND_LEGAL_CLIENTNAME_CHARACTERS) != len) {
return 0;
}
return 1;
}
/** Called when we get a rendezvous-related relay cell on circuit
* <b>circ</b>. Dispatch on rendezvous relay command. */
void
rend_process_relay_cell(circuit_t *circ, const crypt_path_t *layer_hint,
int command, size_t length,
const uint8_t *payload)
{
or_circuit_t *or_circ = NULL;
origin_circuit_t *origin_circ = NULL;
int r = -2;
if (CIRCUIT_IS_ORIGIN(circ)) {
origin_circ = TO_ORIGIN_CIRCUIT(circ);
if (!layer_hint || layer_hint != origin_circ->cpath->prev) {
log_fn(LOG_PROTOCOL_WARN, LD_APP,
"Relay cell (rend purpose %d) from wrong hop on origin circ",
command);
origin_circ = NULL;
}
} else {
or_circ = TO_OR_CIRCUIT(circ);
}
switch (command) {
case RELAY_COMMAND_ESTABLISH_INTRO:
if (or_circ)
r = hs_intro_received_establish_intro(or_circ,payload,length);
break;
case RELAY_COMMAND_ESTABLISH_RENDEZVOUS:
if (or_circ)
r = rend_mid_establish_rendezvous(or_circ,payload,length);
break;
case RELAY_COMMAND_INTRODUCE1:
if (or_circ)
r = hs_intro_received_introduce1(or_circ,payload,length);
break;
case RELAY_COMMAND_INTRODUCE2:
if (origin_circ)
r = hs_service_receive_introduce2(origin_circ,payload,length);
break;
case RELAY_COMMAND_INTRODUCE_ACK:
if (origin_circ)
r = hs_client_receive_introduce_ack(origin_circ,payload,length);
break;
case RELAY_COMMAND_RENDEZVOUS1:
if (or_circ)
r = rend_mid_rendezvous(or_circ,payload,length);
break;
case RELAY_COMMAND_RENDEZVOUS2:
if (origin_circ)
r = hs_client_receive_rendezvous2(origin_circ,payload,length);
break;
case RELAY_COMMAND_INTRO_ESTABLISHED:
if (origin_circ)
r = hs_service_receive_intro_established(origin_circ,payload,length);
break;
case RELAY_COMMAND_RENDEZVOUS_ESTABLISHED:
if (origin_circ)
r = hs_client_receive_rendezvous_acked(origin_circ,payload,length);
break;
default:
tor_fragile_assert();
}
if (r == 0 && origin_circ) {
/* This was a valid cell. Count it as delivered + overhead. */
circuit_read_valid_data(origin_circ, length);
}
if (r == -2)
log_info(LD_PROTOCOL, "Dropping cell (type %d) for wrong circuit type.",
command);
}
/** Determine the routers that are responsible for <b>id</b> (binary) and
* add pointers to those routers' routerstatus_t to <b>responsible_dirs</b>.
* Return -1 if we're returning an empty smartlist, else return 0.
*/
int
hid_serv_get_responsible_directories(smartlist_t *responsible_dirs,
const char *id)
{
int start, found, n_added = 0, i;
networkstatus_t *c = networkstatus_get_latest_consensus();
if (!c || !smartlist_len(c->routerstatus_list)) {
log_info(LD_REND, "We don't have a consensus, so we can't perform v2 "
"rendezvous operations.");
return -1;
}
tor_assert(id);
start = networkstatus_vote_find_entry_idx(c, id, &found);
if (start == smartlist_len(c->routerstatus_list)) start = 0;
i = start;
do {
routerstatus_t *r = smartlist_get(c->routerstatus_list, i);
if (r->is_hs_dir) {
smartlist_add(responsible_dirs, r);
if (++n_added == REND_NUMBER_OF_CONSECUTIVE_REPLICAS)
return 0;
}
if (++i == smartlist_len(c->routerstatus_list))
i = 0;
} while (i != start);
/* Even though we don't have the desired number of hidden service
* directories, be happy if we got any. */
return smartlist_len(responsible_dirs) ? 0 : -1;
}
/* Length of the 'extended' auth cookie used to encode auth type before
* base64 encoding. */
#define REND_DESC_COOKIE_LEN_EXT (REND_DESC_COOKIE_LEN + 1)
/* Length of the zero-padded auth cookie when base64 encoded. These two
* padding bytes always (A=) are stripped off of the returned cookie. */
#define REND_DESC_COOKIE_LEN_EXT_BASE64 (REND_DESC_COOKIE_LEN_BASE64 + 2)
/** Encode a client authorization descriptor cookie.
* The result of this function is suitable for use in the HidServAuth
* option. The trailing padding characters are removed, and the
* auth type is encoded into the cookie.
*
* Returns a new base64-encoded cookie. This function cannot fail.
* The caller is responsible for freeing the returned value.
*/
char *
rend_auth_encode_cookie(const uint8_t *cookie_in, rend_auth_type_t auth_type)
{
uint8_t extended_cookie[REND_DESC_COOKIE_LEN_EXT];
char *cookie_out = tor_malloc_zero(REND_DESC_COOKIE_LEN_EXT_BASE64 + 1);
int re;
tor_assert(cookie_in);
memcpy(extended_cookie, cookie_in, REND_DESC_COOKIE_LEN);
extended_cookie[REND_DESC_COOKIE_LEN] = ((int)auth_type - 1) << 4;
re = base64_encode(cookie_out, REND_DESC_COOKIE_LEN_EXT_BASE64 + 1,
(const char *) extended_cookie, REND_DESC_COOKIE_LEN_EXT,
0);
tor_assert(re == REND_DESC_COOKIE_LEN_EXT_BASE64);
/* Remove the trailing 'A='. Auth type is encoded in the high bits
* of the last byte, so the last base64 character will always be zero
* (A). This is subtly different behavior from base64_encode_nopad. */
cookie_out[REND_DESC_COOKIE_LEN_BASE64] = '\0';
memwipe(extended_cookie, 0, sizeof(extended_cookie));
return cookie_out;
}
/** Decode a base64-encoded client authorization descriptor cookie.
* The descriptor_cookie can be truncated to REND_DESC_COOKIE_LEN_BASE64
* characters (as given to clients), or may include the two padding
* characters (as stored by the service).
*
* The result is stored in REND_DESC_COOKIE_LEN bytes of cookie_out.
* The rend_auth_type_t decoded from the cookie is stored in the
* optional auth_type_out parameter.
*
* Return 0 on success, or -1 on error. The caller is responsible for
* freeing the returned err_msg.
*/
int
rend_auth_decode_cookie(const char *cookie_in, uint8_t *cookie_out,
rend_auth_type_t *auth_type_out, char **err_msg_out)
{
uint8_t descriptor_cookie_decoded[REND_DESC_COOKIE_LEN_EXT + 1] = { 0 };
char descriptor_cookie_base64ext[REND_DESC_COOKIE_LEN_EXT_BASE64 + 1];
const char *descriptor_cookie = cookie_in;
char *err_msg = NULL;
int auth_type_val = 0;
int res = -1;
int decoded_len;
size_t len = strlen(descriptor_cookie);
if (len == REND_DESC_COOKIE_LEN_BASE64) {
/* Add a trailing zero byte to make base64-decoding happy. */
tor_snprintf(descriptor_cookie_base64ext,
sizeof(descriptor_cookie_base64ext),
"%sA=", descriptor_cookie);
descriptor_cookie = descriptor_cookie_base64ext;
} else if (len != REND_DESC_COOKIE_LEN_EXT_BASE64) {
tor_asprintf(&err_msg, "Authorization cookie has wrong length: %s",
escaped(cookie_in));
goto err;
}
decoded_len = base64_decode((char *) descriptor_cookie_decoded,
sizeof(descriptor_cookie_decoded),
descriptor_cookie,
REND_DESC_COOKIE_LEN_EXT_BASE64);
if (decoded_len != REND_DESC_COOKIE_LEN &&
decoded_len != REND_DESC_COOKIE_LEN_EXT) {
tor_asprintf(&err_msg, "Authorization cookie has invalid characters: %s",
escaped(cookie_in));
goto err;
}
if (auth_type_out) {
auth_type_val = (descriptor_cookie_decoded[REND_DESC_COOKIE_LEN] >> 4) + 1;
if (auth_type_val < 1 || auth_type_val > 2) {
tor_asprintf(&err_msg, "Authorization cookie type is unknown: %s",
escaped(cookie_in));
goto err;
}
*auth_type_out = auth_type_val == 1 ? REND_BASIC_AUTH : REND_STEALTH_AUTH;
}
memcpy(cookie_out, descriptor_cookie_decoded, REND_DESC_COOKIE_LEN);
res = 0;
err:
if (err_msg_out) {
*err_msg_out = err_msg;
} else {
tor_free(err_msg);
}
memwipe(descriptor_cookie_decoded, 0, sizeof(descriptor_cookie_decoded));
memwipe(descriptor_cookie_base64ext, 0, sizeof(descriptor_cookie_base64ext));
return res;
}
/* Is this a rend client or server that allows direct (non-anonymous)
* connections?
* Onion services can be configured to start in this mode for single onion. */
int
rend_allow_non_anonymous_connection(const or_options_t* options)
{
return rend_service_allow_non_anonymous_connection(options);
}
/* Is this a rend client or server in non-anonymous mode?
* Onion services can be configured to start in this mode for single onion. */
int
rend_non_anonymous_mode_enabled(const or_options_t *options)
{
return rend_service_non_anonymous_mode_enabled(options);
}
/* Make sure that tor only builds one-hop circuits when they would not
* compromise user anonymity.
*
* One-hop circuits are permitted in Single Onion modes.
*
* Single Onion modes are also allowed to make multi-hop circuits.
* For example, single onion HSDir circuits are 3-hop to prevent denial of
* service.
*/
void
assert_circ_anonymity_ok(const origin_circuit_t *circ,
const or_options_t *options)
{
tor_assert(options);
tor_assert(circ);
tor_assert(circ->build_state);
if (circ->build_state->onehop_tunnel) {
tor_assert(rend_allow_non_anonymous_connection(options));
}
}
/* Return 1 iff the given <b>digest</b> of a permenanent hidden service key is
* equal to the digest in the origin circuit <b>ocirc</b> of its rend data .
* If the rend data doesn't exist, 0 is returned. This function is agnostic to
* the rend data version. */
int
rend_circuit_pk_digest_eq(const origin_circuit_t *ocirc,
const uint8_t *digest)
{
size_t rend_pk_digest_len;
const uint8_t *rend_pk_digest;
tor_assert(ocirc);
tor_assert(digest);
if (ocirc->rend_data == NULL) {
goto no_match;
}
rend_pk_digest = rend_data_get_pk_digest(ocirc->rend_data,
&rend_pk_digest_len);
if (tor_memeq(rend_pk_digest, digest, rend_pk_digest_len)) {
goto match;
}
no_match:
return 0;
match:
return 1;
}
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