/* * onion_announce.c -- Implementation of the announce 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 . * */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include "onion_announce.h" #include "LAN_discovery.h" #include "util.h" #define PING_ID_TIMEOUT 20 #define ANNOUNCE_REQUEST_SIZE (1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + crypto_box_MACBYTES) #define ANNOUNCE_REQUEST_SIZE_RECV (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) /* 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, Onion_Path *path, Node_format dest, uint8_t *public_key, uint8_t *secret_key, uint8_t *ping_id, uint8_t *client_id, uint8_t *data_public_key, uint64_t sendback_data) { uint8_t plain[ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH]; memcpy(plain, ping_id, ONION_PING_ID_SIZE); memcpy(plain + ONION_PING_ID_SIZE, client_id, crypto_box_PUBLICKEYBYTES); memcpy(plain + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES, data_public_key, crypto_box_PUBLICKEYBYTES); memcpy(plain + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES, &sendback_data, sizeof(sendback_data)); uint8_t packet[ANNOUNCE_REQUEST_SIZE]; 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_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES); if ((uint32_t)len + 1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES != ANNOUNCE_REQUEST_SIZE) return -1; memcpy(packet + 1 + crypto_box_NONCEBYTES, public_key, crypto_box_PUBLICKEYBYTES); return send_onion_packet(net, path, dest.ip_port, packet, sizeof(packet)); } /* 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, Onion_Path *path, IP_Port dest, uint8_t *public_key, uint8_t *encrypt_public_key, uint8_t *nonce, uint8_t *data, uint16_t length) { if ((unsigned int)DATA_REQUEST_MIN_SIZE + length > ONION_MAX_DATA_SIZE) return -1; uint8_t packet[DATA_REQUEST_MIN_SIZE + length]; packet[0] = NET_PACKET_ONION_DATA_REQUEST; memcpy(packet + 1, public_key, crypto_box_PUBLICKEYBYTES); memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES, nonce, crypto_box_NONCEBYTES); 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); memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES, random_public_key, crypto_box_PUBLICKEYBYTES); int len = encrypt_data(encrypt_public_key, random_secret_key, packet + 1 + crypto_box_PUBLICKEYBYTES, data, length, packet + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES); if (1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + (uint32_t)len != sizeof(packet)) return -1; return send_onion_packet(net, path, dest, packet, sizeof(packet)); } /* Generate a ping_id and put it in ping_id */ static void generate_ping_id(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_box_KEYBYTES + sizeof(time) + crypto_box_PUBLICKEYBYTES + sizeof(ret_ip_port)]; memcpy(data, onion_a->secret_bytes, crypto_box_KEYBYTES); memcpy(data + crypto_box_KEYBYTES, &time, sizeof(time)); memcpy(data + crypto_box_KEYBYTES + sizeof(time), public_key, crypto_box_PUBLICKEYBYTES); memcpy(data + crypto_box_KEYBYTES + sizeof(time) + crypto_box_PUBLICKEYBYTES, &ret_ip_port, sizeof(ret_ip_port)); crypto_hash_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) { uint32_t i; for (i = 0; i < ONION_ANNOUNCE_MAX_ENTRIES; ++i) { if (!is_timeout(onion_a->entries[i].time, ONION_ANNOUNCE_TIMEOUT) && memcmp(onion_a->entries[i].public_key, public_key, crypto_box_PUBLICKEYBYTES) == 0) return i; } return -1; } static uint8_t cmp_public_key[crypto_box_PUBLICKEYBYTES]; static int cmp_entry(const void *a, const void *b) { Onion_Announce_Entry entry1, entry2; memcpy(&entry1, a, sizeof(Onion_Announce_Entry)); memcpy(&entry2, b, sizeof(Onion_Announce_Entry)); int t1 = is_timeout(entry1.time, ONION_ANNOUNCE_TIMEOUT); int t2 = is_timeout(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; } /* 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); uint32_t i; if (pos == -1) { for (i = 0; i < ONION_ANNOUNCE_MAX_ENTRIES; ++i) { if (is_timeout(onion_a->entries[i].time, ONION_ANNOUNCE_TIMEOUT)) pos = i; } } if (pos == -1) { if (id_closest(onion_a->dht->self_public_key, 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_box_PUBLICKEYBYTES); 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_box_PUBLICKEYBYTES); onion_a->entries[pos].time = unix_time(); memcpy(cmp_public_key, onion_a->dht->self_public_key, crypto_box_PUBLICKEYBYTES); qsort(onion_a->entries, ONION_ANNOUNCE_MAX_ENTRIES, sizeof(Onion_Announce_Entry), cmp_entry); return in_entries(onion_a, public_key); } static int handle_announce_request(void *object, IP_Port source, const uint8_t *packet, uint32_t length) { Onion_Announce *onion_a = object; if (length != ANNOUNCE_REQUEST_SIZE_RECV) return 1; const uint8_t *packet_public_key = packet + 1 + crypto_box_NONCEBYTES; uint8_t shared_key[crypto_box_BEFORENMBYTES]; get_shared_key(&onion_a->shared_keys_recv, shared_key, onion_a->dht->self_secret_key, packet_public_key); uint8_t plain[ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH]; int len = decrypt_data_symmetric(shared_key, packet + 1, packet + 1 + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES, ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + crypto_box_MACBYTES, plain); if ((uint32_t)len != sizeof(plain)) return 1; uint8_t ping_id1[ONION_PING_ID_SIZE]; generate_ping_id(onion_a, unix_time(), packet_public_key, source, ping_id1); uint8_t ping_id2[ONION_PING_ID_SIZE]; generate_ping_id(onion_a, unix_time() + PING_ID_TIMEOUT, packet_public_key, source, ping_id2); int index = -1; uint8_t *data_public_key = plain + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES; if (memcmp(ping_id1, plain, ONION_PING_ID_SIZE) == 0 || 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]; uint32_t num_nodes = get_close_nodes(onion_a->dht, plain + ONION_PING_ID_SIZE, nodes_list, 0, LAN_ip(source.ip) == 0, 1); uint8_t nonce[crypto_box_NONCEBYTES]; 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 (memcmp(onion_a->entries[index].public_key, packet_public_key, crypto_box_PUBLICKEYBYTES) == 0 && memcmp(onion_a->entries[index].data_public_key, data_public_key, crypto_box_PUBLICKEYBYTES) != 0) { pl[0] = 0; memcpy(pl + 1, ping_id2, ONION_PING_ID_SIZE); } else { pl[0] = 1; memcpy(pl + 1, onion_a->entries[index].data_public_key, crypto_box_PUBLICKEYBYTES); } } 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_box_NONCEBYTES); if (len != 1 + ONION_PING_ID_SIZE + nodes_length + crypto_box_MACBYTES) return 1; data[0] = NET_PACKET_ANNOUNCE_RESPONSE; memcpy(data + 1, plain + ONION_PING_ID_SIZE + crypto_box_PUBLICKEYBYTES + crypto_box_PUBLICKEYBYTES, ONION_ANNOUNCE_SENDBACK_DATA_LENGTH); memcpy(data + 1 + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH, nonce, crypto_box_NONCEBYTES); if (send_onion_response(onion_a->net, source, data, 1 + ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + crypto_box_NONCEBYTES + 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, uint32_t length) { Onion_Announce *onion_a = 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; uint8_t data[length - (crypto_box_PUBLICKEYBYTES + ONION_RETURN_3)]; data[0] = NET_PACKET_ONION_DATA_RESPONSE; memcpy(data + 1, packet + 1 + crypto_box_PUBLICKEYBYTES, length - (1 + crypto_box_PUBLICKEYBYTES + ONION_RETURN_3)); if (send_onion_response(onion_a->net, onion_a->entries[index].ret_ip_port, data, sizeof(data), onion_a->entries[index].ret) == -1) return 1; return 0; } Onion_Announce *new_onion_announce(DHT *dht) { if (dht == NULL) return NULL; Onion_Announce *onion_a = calloc(1, sizeof(Onion_Announce)); if (onion_a == NULL) return NULL; onion_a->dht = dht; onion_a->net = dht->net; 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 == NULL) return; networking_registerhandler(onion_a->net, NET_PACKET_ANNOUNCE_REQUEST, NULL, NULL); networking_registerhandler(onion_a->net, NET_PACKET_ONION_DATA_REQUEST, NULL, NULL); free(onion_a); }