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toxcore/toxcore/onion.c
irungentoo bd67129c3e
Added a define for the length of onion paths.
2015-05-01 15:46:48 -04:00

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/*
* onion.c -- Implementation of the onion part of docs/Prevent_Tracking.txt
*
* Copyright (C) 2013 Tox project All Rights Reserved.
*
* This file is part of Tox.
*
* Tox is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Tox is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Tox. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "onion.h"
#include "util.h"
#define RETURN_1 ONION_RETURN_1
#define RETURN_2 ONION_RETURN_2
#define RETURN_3 ONION_RETURN_3
#define SEND_BASE ONION_SEND_BASE
#define SEND_3 ONION_SEND_3
#define SEND_2 ONION_SEND_2
#define SEND_1 ONION_SEND_1
/* Change symmetric keys every 2 hours to make paths expire eventually. */
#define KEY_REFRESH_INTERVAL (2 * 60 * 60)
static void change_symmetric_key(Onion *onion)
{
if (is_timeout(onion->timestamp, KEY_REFRESH_INTERVAL)) {
new_symmetric_key(onion->secret_symmetric_key);
onion->timestamp = unix_time();
}
}
/* packing and unpacking functions */
static void ip_pack(uint8_t *data, IP source)
{
to_net_family(&source);
data[0] = source.family;
if (source.family == TOX_AF_INET || source.family == TOX_TCP_INET) {
memset(data + 1, 0, SIZE_IP6);
memcpy(data + 1, source.ip4.uint8, SIZE_IP4);
} else {
memcpy(data + 1, source.ip6.uint8, SIZE_IP6);
}
}
/* return 0 on success, -1 on failure. */
static int ip_unpack(IP *target, const uint8_t *data, unsigned int data_size, _Bool disable_family_check)
{
if (data_size < (1 + SIZE_IP6))
return -1;
target->family = data[0];
if (target->family == TOX_AF_INET || target->family == TOX_TCP_INET) {
memcpy(target->ip4.uint8, data + 1, SIZE_IP4);
} else {
memcpy(target->ip6.uint8, data + 1, SIZE_IP6);
}
if (!disable_family_check) {
return to_host_family(target);
} else {
to_host_family(target);
return 0;
}
}
static void ipport_pack(uint8_t *data, const IP_Port *source)
{
ip_pack(data, source->ip);
memcpy(data + SIZE_IP, &source->port, SIZE_PORT);
}
/* return 0 on success, -1 on failure. */
static int ipport_unpack(IP_Port *target, const uint8_t *data, unsigned int data_size, _Bool disable_family_check)
{
if (data_size < (SIZE_IP + SIZE_PORT))
return -1;
if (ip_unpack(&target->ip, data, data_size, disable_family_check) == -1)
return -1;
memcpy(&target->port, data + SIZE_IP, SIZE_PORT);
return 0;
}
/* Create a new onion path.
*
* Create a new onion path out of nodes (nodes is a list of ONION_PATH_LENGTH nodes)
*
* new_path must be an empty memory location of atleast Onion_Path size.
*
* return -1 on failure.
* return 0 on success.
*/
int create_onion_path(const DHT *dht, Onion_Path *new_path, const Node_format *nodes)
{
if (!new_path || !nodes)
return -1;
encrypt_precompute(nodes[0].public_key, dht->self_secret_key, new_path->shared_key1);
memcpy(new_path->public_key1, dht->self_public_key, crypto_box_PUBLICKEYBYTES);
uint8_t random_public_key[crypto_box_PUBLICKEYBYTES];
uint8_t random_secret_key[crypto_box_SECRETKEYBYTES];
crypto_box_keypair(random_public_key, random_secret_key);
encrypt_precompute(nodes[1].public_key, random_secret_key, new_path->shared_key2);
memcpy(new_path->public_key2, random_public_key, crypto_box_PUBLICKEYBYTES);
crypto_box_keypair(random_public_key, random_secret_key);
encrypt_precompute(nodes[2].public_key, random_secret_key, new_path->shared_key3);
memcpy(new_path->public_key3, random_public_key, crypto_box_PUBLICKEYBYTES);
new_path->ip_port1 = nodes[0].ip_port;
new_path->ip_port2 = nodes[1].ip_port;
new_path->ip_port3 = nodes[2].ip_port;
memcpy(new_path->node_public_key1, nodes[0].public_key, crypto_box_PUBLICKEYBYTES);
memcpy(new_path->node_public_key2, nodes[1].public_key, crypto_box_PUBLICKEYBYTES);
memcpy(new_path->node_public_key3, nodes[2].public_key, crypto_box_PUBLICKEYBYTES);
return 0;
}
/* Dump nodes in onion path to nodes of length num_nodes;
*
* return -1 on failure.
* return 0 on success.
*/
int onion_path_to_nodes(Node_format *nodes, unsigned int num_nodes, const Onion_Path *path)
{
if (num_nodes < ONION_PATH_LENGTH)
return -1;
nodes[0].ip_port = path->ip_port1;
nodes[1].ip_port = path->ip_port2;
nodes[2].ip_port = path->ip_port3;
memcpy(nodes[0].public_key, path->node_public_key1, crypto_box_PUBLICKEYBYTES);
memcpy(nodes[1].public_key, path->node_public_key2, crypto_box_PUBLICKEYBYTES);
memcpy(nodes[2].public_key, path->node_public_key3, crypto_box_PUBLICKEYBYTES);
return 0;
}
/* Create a onion packet.
*
* Use Onion_Path path to create packet for data of length to dest.
* Maximum length of data is ONION_MAX_DATA_SIZE.
* packet should be at least ONION_MAX_PACKET_SIZE big.
*
* return -1 on failure.
* return length of created packet on success.
*/
int create_onion_packet(uint8_t *packet, uint16_t max_packet_length, const Onion_Path *path, IP_Port dest,
const uint8_t *data, uint16_t length)
{
if (1 + length + SEND_1 > max_packet_length || length == 0)
return -1;
uint8_t step1[SIZE_IPPORT + length];
ipport_pack(step1, &dest);
memcpy(step1 + SIZE_IPPORT, data, length);
uint8_t nonce[crypto_box_NONCEBYTES];
random_nonce(nonce);
uint8_t step2[SIZE_IPPORT + SEND_BASE + length];
ipport_pack(step2, &path->ip_port3);
memcpy(step2 + SIZE_IPPORT, path->public_key3, crypto_box_PUBLICKEYBYTES);
int len = encrypt_data_symmetric(path->shared_key3, nonce, step1, sizeof(step1),
step2 + SIZE_IPPORT + crypto_box_PUBLICKEYBYTES);
if (len != SIZE_IPPORT + length + crypto_box_MACBYTES)
return -1;
uint8_t step3[SIZE_IPPORT + SEND_BASE * 2 + length];
ipport_pack(step3, &path->ip_port2);
memcpy(step3 + SIZE_IPPORT, path->public_key2, crypto_box_PUBLICKEYBYTES);
len = encrypt_data_symmetric(path->shared_key2, nonce, step2, sizeof(step2),
step3 + SIZE_IPPORT + crypto_box_PUBLICKEYBYTES);
if (len != SIZE_IPPORT + SEND_BASE + length + crypto_box_MACBYTES)
return -1;
packet[0] = NET_PACKET_ONION_SEND_INITIAL;
memcpy(packet + 1, nonce, crypto_box_NONCEBYTES);
memcpy(packet + 1 + crypto_box_NONCEBYTES, path->public_key1, crypto_box_PUBLICKEYBYTES);
len = encrypt_data_symmetric(path->shared_key1, nonce, step3, sizeof(step3),
packet + 1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES);
if (len != SIZE_IPPORT + SEND_BASE * 2 + length + crypto_box_MACBYTES)
return -1;
return 1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + len;
}
/* Create a onion packet to be sent over tcp.
*
* Use Onion_Path path to create packet for data of length to dest.
* Maximum length of data is ONION_MAX_DATA_SIZE.
* packet should be at least ONION_MAX_PACKET_SIZE big.
*
* return -1 on failure.
* return length of created packet on success.
*/
int create_onion_packet_tcp(uint8_t *packet, uint16_t max_packet_length, const Onion_Path *path, IP_Port dest,
const uint8_t *data, uint16_t length)
{
if (crypto_box_NONCEBYTES + SIZE_IPPORT + SEND_BASE * 2 + length > max_packet_length || length == 0)
return -1;
uint8_t step1[SIZE_IPPORT + length];
ipport_pack(step1, &dest);
memcpy(step1 + SIZE_IPPORT, data, length);
uint8_t nonce[crypto_box_NONCEBYTES];
random_nonce(nonce);
uint8_t step2[SIZE_IPPORT + SEND_BASE + length];
ipport_pack(step2, &path->ip_port3);
memcpy(step2 + SIZE_IPPORT, path->public_key3, crypto_box_PUBLICKEYBYTES);
int len = encrypt_data_symmetric(path->shared_key3, nonce, step1, sizeof(step1),
step2 + SIZE_IPPORT + crypto_box_PUBLICKEYBYTES);
if (len != SIZE_IPPORT + length + crypto_box_MACBYTES)
return -1;
ipport_pack(packet + crypto_box_NONCEBYTES, &path->ip_port2);
memcpy(packet + crypto_box_NONCEBYTES + SIZE_IPPORT, path->public_key2, crypto_box_PUBLICKEYBYTES);
len = encrypt_data_symmetric(path->shared_key2, nonce, step2, sizeof(step2),
packet + crypto_box_NONCEBYTES + SIZE_IPPORT + crypto_box_PUBLICKEYBYTES);
if (len != SIZE_IPPORT + SEND_BASE + length + crypto_box_MACBYTES)
return -1;
memcpy(packet, nonce, crypto_box_NONCEBYTES);
return crypto_box_NONCEBYTES + SIZE_IPPORT + crypto_box_PUBLICKEYBYTES + len;
}
/* Create and send a onion packet.
*
* Use Onion_Path path to send data of length to dest.
* Maximum length of data is ONION_MAX_DATA_SIZE.
*
* return -1 on failure.
* return 0 on success.
*/
int send_onion_packet(Networking_Core *net, const Onion_Path *path, IP_Port dest, const uint8_t *data, uint16_t length)
{
uint8_t packet[ONION_MAX_PACKET_SIZE];
int len = create_onion_packet(packet, sizeof(packet), path, dest, data, length);
if (len == -1)
return -1;
if (sendpacket(net, path->ip_port1, packet, len) != len)
return -1;
return 0;
}
/* Create and send a onion response sent initially to dest with.
* Maximum length of data is ONION_RESPONSE_MAX_DATA_SIZE.
*
* return -1 on failure.
* return 0 on success.
*/
int send_onion_response(Networking_Core *net, IP_Port dest, const uint8_t *data, uint16_t length, const uint8_t *ret)
{
if (length > ONION_RESPONSE_MAX_DATA_SIZE || length == 0)
return -1;
uint8_t packet[1 + RETURN_3 + length];
packet[0] = NET_PACKET_ONION_RECV_3;
memcpy(packet + 1, ret, RETURN_3);
memcpy(packet + 1 + RETURN_3, data, length);
if ((uint32_t)sendpacket(net, dest, packet, sizeof(packet)) != sizeof(packet))
return -1;
return 0;
}
static int handle_send_initial(void *object, IP_Port source, const uint8_t *packet, uint16_t length)
{
Onion *onion = object;
if (length > ONION_MAX_PACKET_SIZE)
return 1;
if (length <= 1 + SEND_1)
return 1;
change_symmetric_key(onion);
uint8_t plain[ONION_MAX_PACKET_SIZE];
uint8_t shared_key[crypto_box_BEFORENMBYTES];
get_shared_key(&onion->shared_keys_1, shared_key, onion->dht->self_secret_key, packet + 1 + crypto_box_NONCEBYTES);
int len = decrypt_data_symmetric(shared_key, packet + 1, packet + 1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES,
length - (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES), plain);
if (len != length - (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + crypto_box_MACBYTES))
return 1;
return onion_send_1(onion, plain, len, source, packet + 1);
}
int onion_send_1(const Onion *onion, const uint8_t *plain, uint16_t len, IP_Port source, const uint8_t *nonce)
{
if (len > ONION_MAX_PACKET_SIZE + SIZE_IPPORT - (1 + crypto_box_NONCEBYTES + ONION_RETURN_1))
return 1;
if (len <= SIZE_IPPORT + SEND_BASE * 2)
return 1;
IP_Port send_to;
if (ipport_unpack(&send_to, plain, len, 0) == -1)
return 1;
uint8_t ip_port[SIZE_IPPORT];
ipport_pack(ip_port, &source);
uint8_t data[ONION_MAX_PACKET_SIZE];
data[0] = NET_PACKET_ONION_SEND_1;
memcpy(data + 1, nonce, crypto_box_NONCEBYTES);
memcpy(data + 1 + crypto_box_NONCEBYTES, plain + SIZE_IPPORT, len - SIZE_IPPORT);
uint16_t data_len = 1 + crypto_box_NONCEBYTES + (len - SIZE_IPPORT);
uint8_t *ret_part = data + data_len;
new_nonce(ret_part);
len = encrypt_data_symmetric(onion->secret_symmetric_key, ret_part, ip_port, SIZE_IPPORT,
ret_part + crypto_box_NONCEBYTES);
if (len != SIZE_IPPORT + crypto_box_MACBYTES)
return 1;
data_len += crypto_box_NONCEBYTES + len;
if ((uint32_t)sendpacket(onion->net, send_to, data, data_len) != data_len)
return 1;
return 0;
}
static int handle_send_1(void *object, IP_Port source, const uint8_t *packet, uint16_t length)
{
Onion *onion = object;
if (length > ONION_MAX_PACKET_SIZE)
return 1;
if (length <= 1 + SEND_2)
return 1;
change_symmetric_key(onion);
uint8_t plain[ONION_MAX_PACKET_SIZE];
uint8_t shared_key[crypto_box_BEFORENMBYTES];
get_shared_key(&onion->shared_keys_2, shared_key, onion->dht->self_secret_key, packet + 1 + crypto_box_NONCEBYTES);
int len = decrypt_data_symmetric(shared_key, packet + 1, packet + 1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES,
length - (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + RETURN_1), plain);
if (len != length - (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + RETURN_1 + crypto_box_MACBYTES))
return 1;
IP_Port send_to;
if (ipport_unpack(&send_to, plain, len, 0) == -1)
return 1;
uint8_t data[ONION_MAX_PACKET_SIZE];
data[0] = NET_PACKET_ONION_SEND_2;
memcpy(data + 1, packet + 1, crypto_box_NONCEBYTES);
memcpy(data + 1 + crypto_box_NONCEBYTES, plain + SIZE_IPPORT, len - SIZE_IPPORT);
uint16_t data_len = 1 + crypto_box_NONCEBYTES + (len - SIZE_IPPORT);
uint8_t *ret_part = data + data_len;
new_nonce(ret_part);
uint8_t ret_data[RETURN_1 + SIZE_IPPORT];
ipport_pack(ret_data, &source);
memcpy(ret_data + SIZE_IPPORT, packet + (length - RETURN_1), RETURN_1);
len = encrypt_data_symmetric(onion->secret_symmetric_key, ret_part, ret_data, sizeof(ret_data),
ret_part + crypto_box_NONCEBYTES);
if (len != RETURN_2 - crypto_box_NONCEBYTES)
return 1;
data_len += crypto_box_NONCEBYTES + len;
if ((uint32_t)sendpacket(onion->net, send_to, data, data_len) != data_len)
return 1;
return 0;
}
static int handle_send_2(void *object, IP_Port source, const uint8_t *packet, uint16_t length)
{
Onion *onion = object;
if (length > ONION_MAX_PACKET_SIZE)
return 1;
if (length <= 1 + SEND_3)
return 1;
change_symmetric_key(onion);
uint8_t plain[ONION_MAX_PACKET_SIZE];
uint8_t shared_key[crypto_box_BEFORENMBYTES];
get_shared_key(&onion->shared_keys_3, shared_key, onion->dht->self_secret_key, packet + 1 + crypto_box_NONCEBYTES);
int len = decrypt_data_symmetric(shared_key, packet + 1, packet + 1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES,
length - (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + RETURN_2), plain);
if (len != length - (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + RETURN_2 + crypto_box_MACBYTES))
return 1;
IP_Port send_to;
if (ipport_unpack(&send_to, plain, len, 0) == -1)
return 1;
uint8_t data[ONION_MAX_PACKET_SIZE];
memcpy(data, plain + SIZE_IPPORT, len - SIZE_IPPORT);
uint16_t data_len = (len - SIZE_IPPORT);
uint8_t *ret_part = data + (len - SIZE_IPPORT);
new_nonce(ret_part);
uint8_t ret_data[RETURN_2 + SIZE_IPPORT];
ipport_pack(ret_data, &source);
memcpy(ret_data + SIZE_IPPORT, packet + (length - RETURN_2), RETURN_2);
len = encrypt_data_symmetric(onion->secret_symmetric_key, ret_part, ret_data, sizeof(ret_data),
ret_part + crypto_box_NONCEBYTES);
if (len != RETURN_3 - crypto_box_NONCEBYTES)
return 1;
data_len += RETURN_3;
if ((uint32_t)sendpacket(onion->net, send_to, data, data_len) != data_len)
return 1;
return 0;
}
static int handle_recv_3(void *object, IP_Port source, const uint8_t *packet, uint16_t length)
{
Onion *onion = object;
if (length > ONION_MAX_PACKET_SIZE)
return 1;
if (length <= 1 + RETURN_3)
return 1;
change_symmetric_key(onion);
uint8_t plain[SIZE_IPPORT + RETURN_2];
int len = decrypt_data_symmetric(onion->secret_symmetric_key, packet + 1, packet + 1 + crypto_box_NONCEBYTES,
SIZE_IPPORT + RETURN_2 + crypto_box_MACBYTES, plain);
if ((uint32_t)len != sizeof(plain))
return 1;
IP_Port send_to;
if (ipport_unpack(&send_to, plain, len, 0) == -1)
return 1;
uint8_t data[ONION_MAX_PACKET_SIZE];
data[0] = NET_PACKET_ONION_RECV_2;
memcpy(data + 1, plain + SIZE_IPPORT, RETURN_2);
memcpy(data + 1 + RETURN_2, packet + 1 + RETURN_3, length - (1 + RETURN_3));
uint16_t data_len = 1 + RETURN_2 + (length - (1 + RETURN_3));
if ((uint32_t)sendpacket(onion->net, send_to, data, data_len) != data_len)
return 1;
return 0;
}
static int handle_recv_2(void *object, IP_Port source, const uint8_t *packet, uint16_t length)
{
Onion *onion = object;
if (length > ONION_MAX_PACKET_SIZE)
return 1;
if (length <= 1 + RETURN_2)
return 1;
change_symmetric_key(onion);
uint8_t plain[SIZE_IPPORT + RETURN_1];
int len = decrypt_data_symmetric(onion->secret_symmetric_key, packet + 1, packet + 1 + crypto_box_NONCEBYTES,
SIZE_IPPORT + RETURN_1 + crypto_box_MACBYTES, plain);
if ((uint32_t)len != sizeof(plain))
return 1;
IP_Port send_to;
if (ipport_unpack(&send_to, plain, len, 0) == -1)
return 1;
uint8_t data[ONION_MAX_PACKET_SIZE];
data[0] = NET_PACKET_ONION_RECV_1;
memcpy(data + 1, plain + SIZE_IPPORT, RETURN_1);
memcpy(data + 1 + RETURN_1, packet + 1 + RETURN_2, length - (1 + RETURN_2));
uint16_t data_len = 1 + RETURN_1 + (length - (1 + RETURN_2));
if ((uint32_t)sendpacket(onion->net, send_to, data, data_len) != data_len)
return 1;
return 0;
}
static int handle_recv_1(void *object, IP_Port source, const uint8_t *packet, uint16_t length)
{
Onion *onion = object;
if (length > ONION_MAX_PACKET_SIZE)
return 1;
if (length <= 1 + RETURN_1)
return 1;
change_symmetric_key(onion);
uint8_t plain[SIZE_IPPORT];
int len = decrypt_data_symmetric(onion->secret_symmetric_key, packet + 1, packet + 1 + crypto_box_NONCEBYTES,
SIZE_IPPORT + crypto_box_MACBYTES, plain);
if ((uint32_t)len != SIZE_IPPORT)
return 1;
IP_Port send_to;
if (ipport_unpack(&send_to, plain, len, 1) == -1)
return 1;
uint16_t data_len = length - (1 + RETURN_1);
if (onion->recv_1_function && send_to.ip.family != AF_INET && send_to.ip.family != AF_INET6)
return onion->recv_1_function(onion->callback_object, send_to, packet + (1 + RETURN_1), data_len);
if ((uint32_t)sendpacket(onion->net, send_to, packet + (1 + RETURN_1), data_len) != data_len)
return 1;
return 0;
}
void set_callback_handle_recv_1(Onion *onion, int (*function)(void *, IP_Port, const uint8_t *, uint16_t), void *object)
{
onion->recv_1_function = function;
onion->callback_object = object;
}
Onion *new_onion(DHT *dht)
{
if (dht == NULL)
return NULL;
Onion *onion = calloc(1, sizeof(Onion));
if (onion == NULL)
return NULL;
onion->dht = dht;
onion->net = dht->net;
new_symmetric_key(onion->secret_symmetric_key);
onion->timestamp = unix_time();
networking_registerhandler(onion->net, NET_PACKET_ONION_SEND_INITIAL, &handle_send_initial, onion);
networking_registerhandler(onion->net, NET_PACKET_ONION_SEND_1, &handle_send_1, onion);
networking_registerhandler(onion->net, NET_PACKET_ONION_SEND_2, &handle_send_2, onion);
networking_registerhandler(onion->net, NET_PACKET_ONION_RECV_3, &handle_recv_3, onion);
networking_registerhandler(onion->net, NET_PACKET_ONION_RECV_2, &handle_recv_2, onion);
networking_registerhandler(onion->net, NET_PACKET_ONION_RECV_1, &handle_recv_1, onion);
return onion;
}
void kill_onion(Onion *onion)
{
if (onion == NULL)
return;
networking_registerhandler(onion->net, NET_PACKET_ONION_SEND_INITIAL, NULL, NULL);
networking_registerhandler(onion->net, NET_PACKET_ONION_SEND_1, NULL, NULL);
networking_registerhandler(onion->net, NET_PACKET_ONION_SEND_2, NULL, NULL);
networking_registerhandler(onion->net, NET_PACKET_ONION_RECV_3, NULL, NULL);
networking_registerhandler(onion->net, NET_PACKET_ONION_RECV_2, NULL, NULL);
networking_registerhandler(onion->net, NET_PACKET_ONION_RECV_1, NULL, NULL);
free(onion);
}
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