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toxcore/toxcore/onion_announce.c

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/* SPDX-License-Identifier: GPL-3.0-or-later
* Copyright © 2016-2018 The TokTok team.
* Copyright © 2013 Tox project.
*/
/*
* Implementation of the announce part of docs/Prevent_Tracking.txt
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "onion_announce.h"
#include <stdlib.h>
#include <string.h>
#include "LAN_discovery.h"
#include "mono_time.h"
#include "util.h"
#define PING_ID_TIMEOUT ONION_ANNOUNCE_TIMEOUT
#define ANNOUNCE_REQUEST_SIZE_RECV (ONION_ANNOUNCE_REQUEST_SIZE + ONION_RETURN_3)
#define DATA_REQUEST_MIN_SIZE ONION_DATA_REQUEST_MIN_SIZE
#define DATA_REQUEST_MIN_SIZE_RECV (DATA_REQUEST_MIN_SIZE + ONION_RETURN_3)
typedef struct Onion_Announce_Entry {
uint8_t public_key[CRYPTO_PUBLIC_KEY_SIZE];
IP_Port ret_ip_port;
uint8_t ret[ONION_RETURN_3];
uint8_t data_public_key[CRYPTO_PUBLIC_KEY_SIZE];
uint64_t time;
} Onion_Announce_Entry;
struct Onion_Announce {
Mono_Time *mono_time;
DHT *dht;
Networking_Core *net;
Onion_Announce_Entry entries[ONION_ANNOUNCE_MAX_ENTRIES];
/* This is CRYPTO_SYMMETRIC_KEY_SIZE long just so we can use new_symmetric_key() to fill it */
uint8_t secret_bytes[CRYPTO_SYMMETRIC_KEY_SIZE];
Shared_Keys shared_keys_recv;
};
uint8_t *onion_announce_entry_public_key(Onion_Announce *onion_a, uint32_t entry)
{
return onion_a->entries[entry].public_key;
}
void onion_announce_entry_set_time(Onion_Announce *onion_a, uint32_t entry, uint64_t time)
{
onion_a->entries[entry].time = time;
}
/* Create an onion announce request packet in packet of max_packet_length (recommended size ONION_ANNOUNCE_REQUEST_SIZE).
*
* dest_client_id is the public key of the node the packet will be sent to.
* public_key and secret_key is the kepair which will be used to encrypt the request.
* ping_id is the ping id that will be sent in the request.
* client_id is the client id of the node we are searching for.
* data_public_key is the public key we want others to encrypt their data packets with.
* sendback_data is the data of ONION_ANNOUNCE_SENDBACK_DATA_LENGTH length that we expect to
* receive back in the response.
*
* return -1 on failure.
* return packet length on success.
*/
int create_announce_request(uint8_t *packet, uint16_t max_packet_length, const uint8_t *dest_client_id,
const uint8_t *public_key, const uint8_t *secret_key, const uint8_t *ping_id, const uint8_t *client_id,
const uint8_t *data_public_key, uint64_t sendback_data)
{
if (max_packet_length < ONION_ANNOUNCE_REQUEST_SIZE) {
return -1;
}
uint8_t plain[ONION_PING_ID_SIZE + CRYPTO_PUBLIC_KEY_SIZE + CRYPTO_PUBLIC_KEY_SIZE +
ONION_ANNOUNCE_SENDBACK_DATA_LENGTH];
memcpy(plain, ping_id, ONION_PING_ID_SIZE);
memcpy(plain + ONION_PING_ID_SIZE, client_id, CRYPTO_PUBLIC_KEY_SIZE);
memcpy(plain + ONION_PING_ID_SIZE + CRYPTO_PUBLIC_KEY_SIZE, data_public_key, CRYPTO_PUBLIC_KEY_SIZE);
memcpy(plain + ONION_PING_ID_SIZE + CRYPTO_PUBLIC_KEY_SIZE + CRYPTO_PUBLIC_KEY_SIZE, &sendback_data,
sizeof(sendback_data));
packet[0] = NET_PACKET_ANNOUNCE_REQUEST;
random_nonce(packet + 1);
int len = encrypt_data(dest_client_id, secret_key, packet + 1, plain, sizeof(plain),
packet + 1 + CRYPTO_NONCE_SIZE + CRYPTO_PUBLIC_KEY_SIZE);
if ((uint32_t)len + 1 + CRYPTO_NONCE_SIZE + CRYPTO_PUBLIC_KEY_SIZE != ONION_ANNOUNCE_REQUEST_SIZE) {
return -1;
}
memcpy(packet + 1 + CRYPTO_NONCE_SIZE, public_key, CRYPTO_PUBLIC_KEY_SIZE);
return ONION_ANNOUNCE_REQUEST_SIZE;
}
/* Create an onion data request packet in packet of max_packet_length (recommended size ONION_MAX_PACKET_SIZE).
*
* public_key is the real public key of the node which we want to send the data of length length to.
* encrypt_public_key is the public key used to encrypt the data packet.
*
* nonce is the nonce to encrypt this packet with
*
* return -1 on failure.
* return 0 on success.
*/
int create_data_request(uint8_t *packet, uint16_t max_packet_length, const uint8_t *public_key,
const uint8_t *encrypt_public_key, const uint8_t *nonce, const uint8_t *data, uint16_t length)
{
if (DATA_REQUEST_MIN_SIZE + length > max_packet_length) {
return -1;
}
if (DATA_REQUEST_MIN_SIZE + length > ONION_MAX_DATA_SIZE) {
return -1;
}
packet[0] = NET_PACKET_ONION_DATA_REQUEST;
memcpy(packet + 1, public_key, CRYPTO_PUBLIC_KEY_SIZE);
memcpy(packet + 1 + CRYPTO_PUBLIC_KEY_SIZE, nonce, CRYPTO_NONCE_SIZE);
uint8_t random_public_key[CRYPTO_PUBLIC_KEY_SIZE];
uint8_t random_secret_key[CRYPTO_SECRET_KEY_SIZE];
crypto_new_keypair(random_public_key, random_secret_key);
memcpy(packet + 1 + CRYPTO_PUBLIC_KEY_SIZE + CRYPTO_NONCE_SIZE, random_public_key, CRYPTO_PUBLIC_KEY_SIZE);
int len = encrypt_data(encrypt_public_key, random_secret_key, packet + 1 + CRYPTO_PUBLIC_KEY_SIZE, data, length,
packet + 1 + CRYPTO_PUBLIC_KEY_SIZE + CRYPTO_NONCE_SIZE + CRYPTO_PUBLIC_KEY_SIZE);
if (1 + CRYPTO_PUBLIC_KEY_SIZE + CRYPTO_NONCE_SIZE + CRYPTO_PUBLIC_KEY_SIZE + len != DATA_REQUEST_MIN_SIZE +
length) {
return -1;
}
return DATA_REQUEST_MIN_SIZE + length;
}
/* Create and send an onion announce request packet.
*
* path is the path the request will take before it is sent to dest.
*
* public_key and secret_key is the kepair which will be used to encrypt the request.
* ping_id is the ping id that will be sent in the request.
* client_id is the client id of the node we are searching for.
* data_public_key is the public key we want others to encrypt their data packets with.
* sendback_data is the data of ONION_ANNOUNCE_SENDBACK_DATA_LENGTH length that we expect to
* receive back in the response.
*
* return -1 on failure.
* return 0 on success.
*/
int send_announce_request(Networking_Core *net, const Onion_Path *path, Node_format dest, const uint8_t *public_key,
const uint8_t *secret_key, const uint8_t *ping_id, const uint8_t *client_id, const uint8_t *data_public_key,
uint64_t sendback_data)
{
uint8_t request[ONION_ANNOUNCE_REQUEST_SIZE];
int len = create_announce_request(request, sizeof(request), dest.public_key, public_key, secret_key, ping_id, client_id,
data_public_key, sendback_data);
if (len != sizeof(request)) {
return -1;
}
uint8_t packet[ONION_MAX_PACKET_SIZE];
len = create_onion_packet(packet, sizeof(packet), path, dest.ip_port, request, sizeof(request));
if (len == -1) {
return -1;
}
if (sendpacket(net, path->ip_port1, packet, len) != len) {
return -1;
}
return 0;
}
/* Create and send an onion data request packet.
*
* path is the path the request will take before it is sent to dest.
* (if dest knows the person with the public_key they should
* send the packet to that person in the form of a response)
*
* public_key is the real public key of the node which we want to send the data of length length to.
* encrypt_public_key is the public key used to encrypt the data packet.
*
* nonce is the nonce to encrypt this packet with
*
* return -1 on failure.
* return 0 on success.
*/
int send_data_request(Networking_Core *net, const Onion_Path *path, IP_Port dest, const uint8_t *public_key,
const uint8_t *encrypt_public_key, const uint8_t *nonce, const uint8_t *data, uint16_t length)
{
uint8_t request[ONION_MAX_DATA_SIZE];
int len = create_data_request(request, sizeof(request), public_key, encrypt_public_key, nonce, data, length);
if (len == -1) {
return -1;
}
uint8_t packet[ONION_MAX_PACKET_SIZE];
len = create_onion_packet(packet, sizeof(packet), path, dest, request, len);
if (len == -1) {
return -1;
}
if (sendpacket(net, path->ip_port1, packet, len) != len) {
return -1;
}
return 0;
}
/* Generate a ping_id and put it in ping_id */
static void generate_ping_id(const Onion_Announce *onion_a, uint64_t time, const uint8_t *public_key,
IP_Port ret_ip_port, uint8_t *ping_id)
{
time /= PING_ID_TIMEOUT;
uint8_t data[CRYPTO_SYMMETRIC_KEY_SIZE + sizeof(time) + CRYPTO_PUBLIC_KEY_SIZE + sizeof(ret_ip_port)];
memcpy(data, onion_a->secret_bytes, CRYPTO_SYMMETRIC_KEY_SIZE);
memcpy(data + CRYPTO_SYMMETRIC_KEY_SIZE, &time, sizeof(time));
memcpy(data + CRYPTO_SYMMETRIC_KEY_SIZE + sizeof(time), public_key, CRYPTO_PUBLIC_KEY_SIZE);
memcpy(data + CRYPTO_SYMMETRIC_KEY_SIZE + sizeof(time) + CRYPTO_PUBLIC_KEY_SIZE, &ret_ip_port, sizeof(ret_ip_port));
crypto_sha256(ping_id, data, sizeof(data));
}
/* check if public key is in entries list
*
* return -1 if no
* return position in list if yes
*/
static int in_entries(const Onion_Announce *onion_a, const uint8_t *public_key)
{
unsigned int i;
for (i = 0; i < ONION_ANNOUNCE_MAX_ENTRIES; ++i) {
if (!mono_time_is_timeout(onion_a->mono_time, onion_a->entries[i].time, ONION_ANNOUNCE_TIMEOUT)
&& public_key_cmp(onion_a->entries[i].public_key, public_key) == 0) {
return i;
}
}
return -1;
}
typedef struct Cmp_data {
const Mono_Time *mono_time;
const uint8_t *base_public_key;
Onion_Announce_Entry entry;
} Cmp_data;
static int cmp_entry(const void *a, const void *b)
{
Cmp_data cmp1, cmp2;
memcpy(&cmp1, a, sizeof(Cmp_data));
memcpy(&cmp2, b, sizeof(Cmp_data));
Onion_Announce_Entry entry1 = cmp1.entry;
Onion_Announce_Entry entry2 = cmp2.entry;
const uint8_t *cmp_public_key = cmp1.base_public_key;
int t1 = mono_time_is_timeout(cmp1.mono_time, entry1.time, ONION_ANNOUNCE_TIMEOUT);
int t2 = mono_time_is_timeout(cmp1.mono_time, entry2.time, ONION_ANNOUNCE_TIMEOUT);
if (t1 && t2) {
return 0;
}
if (t1) {
return -1;
}
if (t2) {
return 1;
}
int close = id_closest(cmp_public_key, entry1.public_key, entry2.public_key);
if (close == 1) {
return 1;
}
if (close == 2) {
return -1;
}
return 0;
}
static void sort_onion_announce_list(Onion_Announce_Entry *list, unsigned int length, const Mono_Time *mono_time,
const uint8_t *comp_public_key)
{
// Pass comp_public_key to qsort with each Client_data entry, so the
// comparison function can use it as the base of comparison.
VLA(Cmp_data, cmp_list, length);
for (uint32_t i = 0; i < length; ++i) {
cmp_list[i].mono_time = mono_time;
cmp_list[i].base_public_key = comp_public_key;
cmp_list[i].entry = list[i];
}
qsort(cmp_list, length, sizeof(Cmp_data), cmp_entry);
for (uint32_t i = 0; i < length; ++i) {
list[i] = cmp_list[i].entry;
}
}
/* add entry to entries list
*
* return -1 if failure
* return position if added
*/
static int add_to_entries(Onion_Announce *onion_a, IP_Port ret_ip_port, const uint8_t *public_key,
const uint8_t *data_public_key, const uint8_t *ret)
{
int pos = in_entries(onion_a, public_key);
if (pos == -1) {
for (unsigned i = 0; i < ONION_ANNOUNCE_MAX_ENTRIES; ++i) {
if (mono_time_is_timeout(onion_a->mono_time, onion_a->entries[i].time, ONION_ANNOUNCE_TIMEOUT)) {
pos = i;
}
}
}
if (pos == -1) {
if (id_closest(dht_get_self_public_key(onion_a->dht), public_key, onion_a->entries[0].public_key) == 1) {
pos = 0;
}
}
if (pos == -1) {
return -1;
}
memcpy(onion_a->entries[pos].public_key, public_key, CRYPTO_PUBLIC_KEY_SIZE);
onion_a->entries[pos].ret_ip_port = ret_ip_port;
memcpy(onion_a->entries[pos].ret, ret, ONION_RETURN_3);
memcpy(onion_a->entries[pos].data_public_key, data_public_key, CRYPTO_PUBLIC_KEY_SIZE);
onion_a->entries[pos].time = mono_time_get(onion_a->mono_time);
sort_onion_announce_list(onion_a->entries, ONION_ANNOUNCE_MAX_ENTRIES, onion_a->mono_time,
dht_get_self_public_key(onion_a->dht));
return in_entries(onion_a, public_key);
}
static int handle_announce_request(void *object, IP_Port source, const uint8_t *packet, uint16_t length, void *userdata)
{
Onion_Announce *onion_a = (Onion_Announce *)object;
if (length != ANNOUNCE_REQUEST_SIZE_RECV) {
return 1;
}
const uint8_t *packet_public_key = packet + 1 + CRYPTO_NONCE_SIZE;
uint8_t shared_key[CRYPTO_SHARED_KEY_SIZE];
get_shared_key(onion_a->mono_time, &onion_a->shared_keys_recv, shared_key, dht_get_self_secret_key(onion_a->dht),
packet_public_key);
uint8_t plain[ONION_PING_ID_SIZE + CRYPTO_PUBLIC_KEY_SIZE + CRYPTO_PUBLIC_KEY_SIZE +
ONION_ANNOUNCE_SENDBACK_DATA_LENGTH];
int len = decrypt_data_symmetric(shared_key, packet + 1, packet + 1 + CRYPTO_NONCE_SIZE + CRYPTO_PUBLIC_KEY_SIZE,
ONION_PING_ID_SIZE + CRYPTO_PUBLIC_KEY_SIZE + CRYPTO_PUBLIC_KEY_SIZE + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH +
CRYPTO_MAC_SIZE, plain);
if ((uint32_t)len != sizeof(plain)) {
return 1;
}
uint8_t ping_id1[ONION_PING_ID_SIZE];
generate_ping_id(onion_a, mono_time_get(onion_a->mono_time), packet_public_key, source, ping_id1);
uint8_t ping_id2[ONION_PING_ID_SIZE];
generate_ping_id(onion_a, mono_time_get(onion_a->mono_time) + PING_ID_TIMEOUT, packet_public_key, source, ping_id2);
int index;
uint8_t *data_public_key = plain + ONION_PING_ID_SIZE + CRYPTO_PUBLIC_KEY_SIZE;
if (crypto_memcmp(ping_id1, plain, ONION_PING_ID_SIZE) == 0
|| crypto_memcmp(ping_id2, plain, ONION_PING_ID_SIZE) == 0) {
index = add_to_entries(onion_a, source, packet_public_key, data_public_key,
packet + (ANNOUNCE_REQUEST_SIZE_RECV - ONION_RETURN_3));
} else {
index = in_entries(onion_a, plain + ONION_PING_ID_SIZE);
}
/*Respond with a announce response packet*/
Node_format nodes_list[MAX_SENT_NODES];
unsigned int num_nodes =
get_close_nodes(onion_a->dht, plain + ONION_PING_ID_SIZE, nodes_list, net_family_unspec, ip_is_lan(source.ip), 1);
uint8_t nonce[CRYPTO_NONCE_SIZE];
random_nonce(nonce);
uint8_t pl[1 + ONION_PING_ID_SIZE + sizeof(nodes_list)];
if (index == -1) {
pl[0] = 0;
memcpy(pl + 1, ping_id2, ONION_PING_ID_SIZE);
} else {
if (public_key_cmp(onion_a->entries[index].public_key, packet_public_key) == 0) {
if (public_key_cmp(onion_a->entries[index].data_public_key, data_public_key) != 0) {
pl[0] = 0;
memcpy(pl + 1, ping_id2, ONION_PING_ID_SIZE);
} else {
pl[0] = 2;
memcpy(pl + 1, ping_id2, ONION_PING_ID_SIZE);
}
} else {
pl[0] = 1;
memcpy(pl + 1, onion_a->entries[index].data_public_key, CRYPTO_PUBLIC_KEY_SIZE);
}
}
int nodes_length = 0;
if (num_nodes != 0) {
nodes_length = pack_nodes(pl + 1 + ONION_PING_ID_SIZE, sizeof(nodes_list), nodes_list, num_nodes);
if (nodes_length <= 0) {
return 1;
}
}
uint8_t data[ONION_ANNOUNCE_RESPONSE_MAX_SIZE];
len = encrypt_data_symmetric(shared_key, nonce, pl, 1 + ONION_PING_ID_SIZE + nodes_length,
data + 1 + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + CRYPTO_NONCE_SIZE);
if (len != 1 + ONION_PING_ID_SIZE + nodes_length + CRYPTO_MAC_SIZE) {
return 1;
}
data[0] = NET_PACKET_ANNOUNCE_RESPONSE;
memcpy(data + 1, plain + ONION_PING_ID_SIZE + CRYPTO_PUBLIC_KEY_SIZE + CRYPTO_PUBLIC_KEY_SIZE,
ONION_ANNOUNCE_SENDBACK_DATA_LENGTH);
memcpy(data + 1 + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH, nonce, CRYPTO_NONCE_SIZE);
if (send_onion_response(onion_a->net, source, data,
1 + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + CRYPTO_NONCE_SIZE + len,
packet + (ANNOUNCE_REQUEST_SIZE_RECV - ONION_RETURN_3)) == -1) {
return 1;
}
return 0;
}
static int handle_data_request(void *object, IP_Port source, const uint8_t *packet, uint16_t length, void *userdata)
{
Onion_Announce *onion_a = (Onion_Announce *)object;
if (length <= DATA_REQUEST_MIN_SIZE_RECV) {
return 1;
}
if (length > ONION_MAX_PACKET_SIZE) {
return 1;
}
int index = in_entries(onion_a, packet + 1);
if (index == -1) {
return 1;
}
VLA(uint8_t, data, length - (CRYPTO_PUBLIC_KEY_SIZE + ONION_RETURN_3));
data[0] = NET_PACKET_ONION_DATA_RESPONSE;
memcpy(data + 1, packet + 1 + CRYPTO_PUBLIC_KEY_SIZE, length - (1 + CRYPTO_PUBLIC_KEY_SIZE + ONION_RETURN_3));
if (send_onion_response(onion_a->net, onion_a->entries[index].ret_ip_port, data, SIZEOF_VLA(data),
onion_a->entries[index].ret) == -1) {
return 1;
}
return 0;
}
Onion_Announce *new_onion_announce(Mono_Time *mono_time, DHT *dht)
{
if (dht == nullptr) {
return nullptr;
}
Onion_Announce *onion_a = (Onion_Announce *)calloc(1, sizeof(Onion_Announce));
if (onion_a == nullptr) {
return nullptr;
}
onion_a->mono_time = mono_time;
onion_a->dht = dht;
onion_a->net = dht_get_net(dht);
new_symmetric_key(onion_a->secret_bytes);
networking_registerhandler(onion_a->net, NET_PACKET_ANNOUNCE_REQUEST, &handle_announce_request, onion_a);
networking_registerhandler(onion_a->net, NET_PACKET_ONION_DATA_REQUEST, &handle_data_request, onion_a);
return onion_a;
}
void kill_onion_announce(Onion_Announce *onion_a)
{
if (onion_a == nullptr) {
return;
}
networking_registerhandler(onion_a->net, NET_PACKET_ANNOUNCE_REQUEST, nullptr, nullptr);
networking_registerhandler(onion_a->net, NET_PACKET_ONION_DATA_REQUEST, nullptr, nullptr);
free(onion_a);
}
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