/* net_crypto.c * * Functions for the core network crypto. * See also: http://wiki.tox.im/index.php/DHT * * NOTE: This code has to be perfect. We don't mess around with encryption. * * 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 "net_crypto.h" #include "util.h" static uint8_t crypt_connection_id_not_valid(Net_Crypto *c, int crypt_connection_id) { return (uint32_t)crypt_connection_id >= c->crypto_connections_length; } /* return 0 if connection is dead. * return 1 if connection is alive. */ static int is_alive(uint8_t status) { if (status == CRYPTO_CONN_COOKIE_REQUESTING || status == CRYPTO_CONN_HANDSHAKE_SENT || status == CRYPTO_CONN_NOT_CONFIRMED || status == CRYPTO_CONN_ESTABLISHED) { return 1; } return 0; } /* cookie timeout in seconds */ #define COOKIE_TIMEOUT 10 #define COOKIE_DATA_LENGTH (crypto_box_PUBLICKEYBYTES * 2) #define COOKIE_CONTENTS_LENGTH (sizeof(uint64_t) + COOKIE_DATA_LENGTH) #define COOKIE_LENGTH (crypto_box_NONCEBYTES + COOKIE_CONTENTS_LENGTH + crypto_box_MACBYTES) #define COOKIE_REQUEST_PLAIN_LENGTH (COOKIE_DATA_LENGTH + sizeof(uint64_t)) #define COOKIE_REQUEST_LENGTH (1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + COOKIE_REQUEST_PLAIN_LENGTH + crypto_box_MACBYTES) #define COOKIE_RESPONSE_LENGTH (1 + crypto_box_NONCEBYTES + COOKIE_LENGTH + sizeof(uint64_t) + crypto_box_MACBYTES) /* Create a cookie request packet and put it in packet. * dht_public_key is the dht public key of the other * real_public_key is the real public key of the other. * * packet must be of size COOKIE_REQUEST_LENGTH or bigger. * * return -1 on failure. * return COOKIE_REQUEST_LENGTH on success. */ static int create_cookie_request(Net_Crypto *c, uint8_t *packet, uint8_t *dht_public_key, uint8_t *real_public_key, uint64_t number, uint8_t *shared_key) { uint8_t plain[COOKIE_REQUEST_PLAIN_LENGTH]; memcpy(plain, c->self_public_key, crypto_box_PUBLICKEYBYTES); memcpy(plain + crypto_box_PUBLICKEYBYTES, real_public_key, crypto_box_PUBLICKEYBYTES); memcpy(plain + (crypto_box_PUBLICKEYBYTES * 2), &number, sizeof(uint64_t)); DHT_get_shared_key_sent(c->dht, shared_key, dht_public_key); uint8_t nonce[crypto_box_NONCEBYTES]; new_nonce(nonce); packet[0] = NET_PACKET_COOKIE_REQUEST; memcpy(packet + 1, c->dht->self_public_key, crypto_box_PUBLICKEYBYTES); memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES, nonce, crypto_box_NONCEBYTES); int len = encrypt_data_symmetric(shared_key, nonce, plain, sizeof(plain), packet + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES); if (len != COOKIE_REQUEST_PLAIN_LENGTH + crypto_box_MACBYTES) return -1; return (1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + len); } /* Create cookie of length COOKIE_LENGTH from bytes of length COOKIE_DATA_LENGTH using encryption_key * * return -1 on failure. * return 0 on success. */ static int create_cookie(uint8_t *cookie, uint8_t *bytes, uint8_t *encryption_key) { uint8_t contents[COOKIE_CONTENTS_LENGTH]; uint64_t temp_time = unix_time(); memcpy(contents, &temp_time, sizeof(temp_time)); memcpy(contents + sizeof(temp_time), bytes, COOKIE_DATA_LENGTH); new_nonce(cookie); int len = encrypt_data_symmetric(encryption_key, cookie, contents, sizeof(contents), cookie + crypto_box_NONCEBYTES); if (len != COOKIE_LENGTH - crypto_box_NONCEBYTES) return -1; return 0; } /* Open cookie of length COOKIE_LENGTH to bytes of length COOKIE_DATA_LENGTH using encryption_key * * return -1 on failure. * return 0 on success. */ static int open_cookie(uint8_t *bytes, uint8_t *cookie, uint8_t *encryption_key) { uint8_t contents[COOKIE_CONTENTS_LENGTH]; int len = decrypt_data_symmetric(encryption_key, cookie, cookie + crypto_box_NONCEBYTES, COOKIE_LENGTH - crypto_box_NONCEBYTES, contents); if (len != sizeof(contents)) return -1; uint64_t cookie_time; memcpy(&cookie_time, contents, sizeof(cookie_time)); uint64_t temp_time = unix_time(); if (cookie_time + COOKIE_TIMEOUT < temp_time || temp_time < cookie_time) return -1; memcpy(bytes, contents + sizeof(cookie_time), COOKIE_DATA_LENGTH); return 0; } /* Create a cookie response packet and put it in packet. * request_plain must be COOKIE_REQUEST_PLAIN_LENGTH bytes. * packet must be of size COOKIE_RESPONSE_LENGTH or bigger. * * return -1 on failure. * return COOKIE_RESPONSE_LENGTH on success. */ static int create_cookie_response(Net_Crypto *c, uint8_t *packet, uint8_t *request_plain, uint8_t *shared_key) { uint8_t plain[COOKIE_LENGTH + sizeof(uint64_t)]; if (create_cookie(plain, request_plain, c->secret_symmetric_key) != 0) return -1; memcpy(plain + COOKIE_LENGTH, request_plain + COOKIE_DATA_LENGTH, sizeof(uint64_t)); packet[0] = NET_PACKET_COOKIE_RESPONSE; new_nonce(packet + 1); int len = encrypt_data_symmetric(shared_key, packet + 1, plain, sizeof(plain), packet + 1 + crypto_box_NONCEBYTES); if (len != COOKIE_RESPONSE_LENGTH - (1 + crypto_box_NONCEBYTES)) return -1; return COOKIE_RESPONSE_LENGTH; } /* Handle the cookie request packet of length length. * Put what was in the request in request_plain (must be of size COOKIE_REQUEST_PLAIN_LENGTH) * Put the key used to decrypt the request into shared_key (of size crypto_box_BEFORENMBYTES) for use in the response. * * return -1 on failure. * return 0 on success. */ static int handle_cookie_request(Net_Crypto *c, uint8_t *request_plain, uint8_t *shared_key, uint8_t *packet, uint16_t length) { if (length != COOKIE_REQUEST_LENGTH) return -1; DHT_get_shared_key_sent(c->dht, shared_key, packet + 1); int len = decrypt_data_symmetric(shared_key, packet + 1 + crypto_box_PUBLICKEYBYTES, packet + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES, COOKIE_REQUEST_PLAIN_LENGTH + crypto_box_MACBYTES, request_plain); if (len != COOKIE_REQUEST_PLAIN_LENGTH) return -1; return 0; } /* Handle the cookie request packet (for raw UDP) */ static int udp_handle_cookie_request(void *object, IP_Port source, uint8_t *packet, uint32_t length) { Net_Crypto *c = object; uint8_t request_plain[COOKIE_REQUEST_PLAIN_LENGTH]; uint8_t shared_key[crypto_box_BEFORENMBYTES]; if (handle_cookie_request(c, request_plain, shared_key, packet, length) != 0) return 1; uint8_t data[COOKIE_RESPONSE_LENGTH]; if (create_cookie_response(c, data, request_plain, shared_key) != sizeof(data)) return 1; if ((uint32_t)sendpacket(c->dht->net, source, data, sizeof(data)) != sizeof(data)) return 1; return 0; } /* Handle a cookie response packet of length encrypted with shared_key. * put the cookie in the response in cookie * * cookie must be of length COOKIE_LENGTH. * * return -1 on failure. * return COOKIE_LENGTH on success. */ static int handle_cookie_response(uint8_t *cookie, uint64_t *number, uint8_t *packet, uint32_t length, uint8_t *shared_key) { if (length != COOKIE_RESPONSE_LENGTH) return -1; uint8_t plain[COOKIE_LENGTH + sizeof(uint64_t)]; int len = decrypt_data_symmetric(shared_key, packet + 1, packet + 1 + crypto_box_NONCEBYTES, length - (1 + crypto_box_NONCEBYTES), plain); if (len != sizeof(plain)) return -1; memcpy(cookie, plain, COOKIE_LENGTH); memcpy(number, plain + COOKIE_LENGTH, sizeof(uint64_t)); return COOKIE_LENGTH; } #define HANDSHAKE_PACKET_LENGTH (1 + COOKIE_LENGTH + crypto_box_NONCEBYTES + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + crypto_hash_sha512_BYTES + COOKIE_LENGTH + crypto_box_MACBYTES) /* Create a handshake packet and put it in packet. * cookie must be COOKIE_LENGTH bytes. * packet must be of size HANDSHAKE_PACKET_LENGTH or bigger. * * return -1 on failure. * return HANDSHAKE_PACKET_LENGTH on success. */ static int create_crypto_handshake(Net_Crypto *c, uint8_t *packet, uint8_t *cookie, uint8_t *nonce, uint8_t *session_pk, uint8_t *peer_real_pk) { uint8_t plain[crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + crypto_hash_sha512_BYTES + COOKIE_LENGTH]; memcpy(plain, nonce, crypto_box_NONCEBYTES); memcpy(plain + crypto_box_NONCEBYTES, session_pk, crypto_box_PUBLICKEYBYTES); crypto_hash_sha512(plain + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES, cookie, COOKIE_LENGTH); uint8_t cookie_plain[COOKIE_DATA_LENGTH]; memcpy(cookie_plain, peer_real_pk, crypto_box_PUBLICKEYBYTES); memcpy(cookie_plain + crypto_box_PUBLICKEYBYTES, c->self_public_key, crypto_box_PUBLICKEYBYTES); if (create_cookie(plain + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + crypto_hash_sha512_BYTES, cookie_plain, c->secret_symmetric_key) != 0) return -1; new_nonce(packet + 1 + COOKIE_LENGTH); int len = encrypt_data(peer_real_pk, c->self_secret_key, packet + 1 + COOKIE_LENGTH, plain, sizeof(plain), packet + 1 + COOKIE_LENGTH + crypto_box_NONCEBYTES); if (len != HANDSHAKE_PACKET_LENGTH - (1 + COOKIE_LENGTH + crypto_box_NONCEBYTES)) return -1; packet[0] = NET_PACKET_CRYPTO_HS; memcpy(packet + 1, cookie, COOKIE_LENGTH); return HANDSHAKE_PACKET_LENGTH; } /* Handle a crypto handshake packet of length. * put the nonce contained in the packet in nonce, * the session public key in session_pk * the real public key of the peer in peer_real_pk and * the cookie inside the encrypted part of the packet in cookie. * * if expected_real_pk isn't NULL it denotes the real public key * the packet should be from. * * nonce must be at least crypto_box_NONCEBYTES * session_pk must be at least crypto_box_PUBLICKEYBYTES * peer_real_pk must be at least crypto_box_PUBLICKEYBYTES * cookie must be at least COOKIE_LENGTH * * return -1 on failure. * return 0 on success. */ static int handle_crypto_handshake(Net_Crypto *c, uint8_t *nonce, uint8_t *session_pk, uint8_t *peer_real_pk, uint8_t *cookie, uint8_t *packet, uint32_t length, uint8_t *expected_real_pk) { if (length != HANDSHAKE_PACKET_LENGTH) return -1; uint8_t cookie_plain[COOKIE_DATA_LENGTH]; if (open_cookie(cookie_plain, packet + 1, c->secret_symmetric_key) != 0) return -1; if (expected_real_pk) if (crypto_cmp(cookie_plain, expected_real_pk, crypto_box_PUBLICKEYBYTES) != 0) return -1; if (crypto_cmp(cookie_plain + crypto_box_PUBLICKEYBYTES, c->self_public_key, crypto_box_PUBLICKEYBYTES) != 0) return -1; uint8_t cookie_hash[crypto_hash_sha512_BYTES]; crypto_hash_sha512(cookie_hash, packet + 1, COOKIE_LENGTH); uint8_t plain[crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + crypto_hash_sha512_BYTES + COOKIE_LENGTH]; int len = decrypt_data(cookie_plain, c->self_secret_key, packet + 1 + COOKIE_LENGTH, packet + 1 + COOKIE_LENGTH + crypto_box_NONCEBYTES, HANDSHAKE_PACKET_LENGTH - (1 + COOKIE_LENGTH + crypto_box_NONCEBYTES), plain); if (len != sizeof(plain)) return -1; if (memcmp(cookie_hash, plain + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES, crypto_hash_sha512_BYTES) != 0) return -1; memcpy(nonce, plain, crypto_box_NONCEBYTES); memcpy(session_pk, plain + crypto_box_NONCEBYTES, crypto_box_PUBLICKEYBYTES); memcpy(cookie, plain + crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + crypto_hash_sha512_BYTES, COOKIE_LENGTH); memcpy(peer_real_pk, cookie_plain, crypto_box_PUBLICKEYBYTES); return 0; } static Crypto_Connection *get_crypto_connection(Net_Crypto *c, int crypt_connection_id) { if (crypt_connection_id_not_valid(c, crypt_connection_id)) return 0; return &c->crypto_connections[crypt_connection_id]; } /* Sends a packet to the peer using the fastest route. * * return -1 on failure. * return 0 on success. */ static int send_packet_to(Net_Crypto *c, int crypt_connection_id, uint8_t *data, uint16_t length) { //TODO TCP, etc... Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; if ((uint32_t)sendpacket(c->dht->net, conn->ip_port, data, length) != length) return -1; return 0; } /** START: Array Related functions **/ /* Return number of packets in array * Note that holes are counted too. */ static uint32_t num_packets_array(Packets_Array *array) { return array->buffer_end - array->buffer_start; } /* Add data with packet number to array. * * return -1 on failure. * return 0 on success. */ static int add_data_to_buffer(Packets_Array *array, uint32_t number, Packet_Data *data) { if (number - array->buffer_start > CRYPTO_PACKET_BUFFER_SIZE) return -1; uint32_t num = number % CRYPTO_PACKET_BUFFER_SIZE; if (array->buffer[num]) return -1; Packet_Data *new_d = malloc(sizeof(Packet_Data)); if (new_d == NULL) return -1; memcpy(new_d, data, sizeof(Packet_Data)); array->buffer[num] = new_d; if ((number - array->buffer_start) >= (array->buffer_end - array->buffer_start)) array->buffer_end = number + 1; return 0; } /* Copy data with packet number to data. * * return -1 on failure. * return 0 on success. */ static int copy_data_number(Packets_Array *array, Packet_Data *data, uint32_t number) { uint32_t num_spots = array->buffer_end - array->buffer_start; if (array->buffer_end - number > num_spots || number - array->buffer_start >= num_spots) return -1; uint32_t num = number % CRYPTO_PACKET_BUFFER_SIZE; if (!array->buffer[num]) return -1; memcpy(data, array->buffer[num], sizeof(Packet_Data)); return 0; } /* Add data to end of array. * * return -1 on failure. * return packet number on success. */ static int64_t add_data_end_of_buffer(Packets_Array *array, Packet_Data *data) { if (num_packets_array(array) >= CRYPTO_PACKET_BUFFER_SIZE) return -1; Packet_Data *new_d = malloc(sizeof(Packet_Data)); if (new_d == NULL) return -1; memcpy(new_d, data, sizeof(Packet_Data)); uint32_t id = array->buffer_end; array->buffer[id % CRYPTO_PACKET_BUFFER_SIZE] = new_d; ++array->buffer_end; return id; } /* Read data from begginning of array. * * return -1 on failure. * return packet number on success. */ static int64_t read_data_beg_buffer(Packets_Array *array, Packet_Data *data) { if (array->buffer_end == array->buffer_start) return -1; uint32_t num = array->buffer_start % CRYPTO_PACKET_BUFFER_SIZE; if (!array->buffer[num]) return -1; memcpy(data, array->buffer[num], sizeof(Packet_Data)); uint32_t id = array->buffer_start; ++array->buffer_start; free(array->buffer[num]); array->buffer[num] = NULL; return id; } /* Delete all packets in array before number (but not number) * * return -1 on failure. * return 0 on success */ static int clear_buffer_until(Packets_Array *array, uint32_t number) { uint32_t num_spots = array->buffer_end - array->buffer_start; if (array->buffer_end - number >= num_spots || number - array->buffer_start > num_spots) return -1; uint32_t i; for (i = array->buffer_start; i != number; ++i) { uint32_t num = i % CRYPTO_PACKET_BUFFER_SIZE; if (array->buffer[num]) { free(array->buffer[num]); array->buffer[num] = NULL; } } array->buffer_start = i; return 0; } /** END: Array Related functions **/ #define MAX_DATA_DATA_PACKET_SIZE (MAX_CRYPTO_PACKET_SIZE - (1 + sizeof(uint16_t) + crypto_box_MACBYTES)) static int send_data_packet(Net_Crypto *c, int crypt_connection_id, uint8_t *data, uint16_t length) { if (length == 0 || length + (1 + sizeof(uint16_t) + crypto_box_MACBYTES) > MAX_CRYPTO_PACKET_SIZE) return -1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; uint8_t packet[1 + sizeof(uint16_t) + length + crypto_box_MACBYTES]; packet[0] = NET_PACKET_CRYPTO_DATA; memcpy(packet + 1, conn->sent_nonce + (crypto_box_NONCEBYTES - sizeof(uint16_t)), sizeof(uint16_t)); int len = encrypt_data_symmetric(conn->shared_key, conn->sent_nonce, data, length, packet + 1 + sizeof(uint16_t)); if (len + 1 + sizeof(uint16_t) != sizeof(packet)) return -1; increment_nonce(conn->sent_nonce); conn->last_data_packet_sent = current_time_monotonic(); //TODO remove this. return send_packet_to(c, crypt_connection_id, packet, sizeof(packet)); } static int send_data_packet_helper(Net_Crypto *c, int crypt_connection_id, uint32_t buffer_start, uint32_t num, uint8_t *data, uint32_t length) { num = htonl(num); buffer_start = htonl(buffer_start); uint8_t packet[sizeof(uint32_t) + sizeof(uint32_t) + length]; memcpy(packet, &buffer_start, sizeof(uint32_t)); memcpy(packet + sizeof(uint32_t), &num, sizeof(uint32_t)); memcpy(packet + (sizeof(uint32_t) * 2), data, length); return send_data_packet(c, crypt_connection_id, packet, sizeof(packet)); } /* return -1 if data could not be put in packet queue. * return positive packet number if data was put into the queue. */ static int64_t send_lossless_packet(Net_Crypto *c, int crypt_connection_id, uint8_t *data, uint32_t length) { if (length == 0 || length > MAX_CRYPTO_DATA_SIZE) return -1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; Packet_Data dt; dt.time = current_time_monotonic(); dt.length = length; memcpy(dt.data, data, length); int64_t packet_num = add_data_end_of_buffer(&conn->send_array, &dt); if (packet_num == -1) return -1; if (send_data_packet_helper(c, crypt_connection_id, conn->recv_array.buffer_start, packet_num, data, length) != 0) printf("send_data_packet failed\n"); return packet_num; } /* Get the lowest 2 bytes from the nonce and convert * them to host byte format before returning them. */ static uint16_t get_nonce_uint16(uint8_t *nonce) { uint16_t num; memcpy(&num, nonce + (crypto_box_NONCEBYTES - sizeof(uint16_t)), sizeof(uint16_t)); return ntohs(num); } #define DATA_NUM_THRESHOLD 21845 /* Handle a data packet. * Decrypt packet of length and put it into data. * data must be at least MAX_DATA_DATA_PACKET_SIZE big. * * return -1 on failure. * return length of data on success. */ static int handle_data_packet(Net_Crypto *c, int crypt_connection_id, uint8_t *data, uint8_t *packet, uint16_t length) { if (length <= (1 + sizeof(uint16_t) + crypto_box_MACBYTES) || length > MAX_CRYPTO_PACKET_SIZE) return -1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; uint8_t nonce[crypto_box_NONCEBYTES]; memcpy(nonce, conn->recv_nonce, crypto_box_NONCEBYTES); uint16_t num_cur_nonce = get_nonce_uint16(nonce); uint16_t num; memcpy(&num, packet + 1, sizeof(uint16_t)); num = ntohs(num); uint16_t diff = num - num_cur_nonce; increment_nonce_number(nonce, diff); int len = decrypt_data_symmetric(conn->shared_key, nonce, packet + 1 + sizeof(uint16_t), length - (1 + sizeof(uint16_t)), data); if ((unsigned int)len != length - (1 + sizeof(uint16_t) + crypto_box_MACBYTES)) return -1; if (diff > DATA_NUM_THRESHOLD * 2) { increment_nonce_number(conn->recv_nonce, DATA_NUM_THRESHOLD); } return len; } /* Add a new temp packet to send repeatedly. * * return -1 on failure. * return 0 on success. */ static int new_temp_packet(Net_Crypto *c, int crypt_connection_id, uint8_t *packet, uint16_t length) { if (length == 0 || length > MAX_CRYPTO_PACKET_SIZE) return -1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; uint8_t *temp_packet = malloc(length); if (temp_packet == 0) return -1; if (conn->temp_packet) free(conn->temp_packet); memcpy(temp_packet, packet, length); conn->temp_packet = temp_packet; conn->temp_packet_length = length; conn->temp_packet_sent_time = 0; conn->temp_packet_num_sent = 0; return 0; } /* Clear the temp packet. * * return -1 on failure. * return 0 on success. */ static int clear_temp_packet(Net_Crypto *c, int crypt_connection_id) { Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; if (conn->temp_packet) free(conn->temp_packet); conn->temp_packet = 0; conn->temp_packet_length = 0; conn->temp_packet_sent_time = 0; conn->temp_packet_num_sent = 0; return 0; } /* Send the temp packet. * * return -1 on failure. * return 0 on success. */ static int send_temp_packet(Net_Crypto *c, int crypt_connection_id) { Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; if (!conn->temp_packet) return -1; if (send_packet_to(c, crypt_connection_id, conn->temp_packet, conn->temp_packet_length) != 0) return -1; conn->temp_packet_sent_time = current_time_monotonic(); ++conn->temp_packet_num_sent; return 0; } /* Create a handshake packet and set it as a temp packet. * cookie must be COOKIE_LENGTH. * * return -1 on failure. * return 0 on success. */ static int create_send_handshake(Net_Crypto *c, int crypt_connection_id, uint8_t *cookie) { Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; uint8_t handshake_packet[HANDSHAKE_PACKET_LENGTH]; if (create_crypto_handshake(c, handshake_packet, cookie, conn->sent_nonce, conn->sessionpublic_key, conn->public_key) != sizeof(handshake_packet)) return -1; if (new_temp_packet(c, crypt_connection_id, handshake_packet, sizeof(handshake_packet)) != 0) return -1; send_temp_packet(c, crypt_connection_id); return 0; } /* Handle a recieved data packet. * * return -1 on failure. * return 0 on success. */ static int handle_data_packet_helper(Net_Crypto *c, int crypt_connection_id, uint8_t *packet, uint16_t length) { if (length > MAX_CRYPTO_PACKET_SIZE || length <= CRYPTO_DATA_PACKET_MIN_SIZE) return -1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; uint8_t data[MAX_DATA_DATA_PACKET_SIZE]; int len = handle_data_packet(c, crypt_connection_id, data, packet, length); if (len <= (int)(sizeof(uint32_t) * 2)) return -1; uint32_t buffer_start, num; memcpy(&buffer_start, data, sizeof(uint32_t)); memcpy(&num, data + sizeof(uint32_t), sizeof(uint32_t)); buffer_start = ntohl(buffer_start); num = ntohl(num); if (buffer_start != conn->send_array.buffer_start && clear_buffer_until(&conn->send_array, buffer_start) != 0) return -1; uint8_t *real_data = data + (sizeof(uint32_t) * 2); uint16_t real_length = len - (sizeof(uint32_t) * 2); while (real_data[0] == 0) { /* Remove Padding */ ++real_data; --real_length; if (real_length == 0) return -1; } if (real_data[0] == PACKET_ID_REQUEST) { if (real_length <= 1) return -1; //TODO } else { Packet_Data dt; dt.time = current_time_monotonic(); dt.length = real_length; memcpy(dt.data, real_data, real_length); if (add_data_to_buffer(&conn->recv_array, num, &dt) != 0) return -1; while (read_data_beg_buffer(&conn->recv_array, &dt) != -1) { if (conn->connection_data_callback) conn->connection_data_callback(conn->connection_data_callback_object, conn->connection_data_callback_id, dt.data, dt.length); } } if (conn->status == CRYPTO_CONN_NOT_CONFIRMED) { if (conn->connection_status_callback) conn->connection_status_callback(conn->connection_status_callback_object, conn->connection_status_callback_id, 1); clear_temp_packet(c, crypt_connection_id); conn->status = CRYPTO_CONN_ESTABLISHED; } return 0; } /* Handle a packet that was recieved for the connection. * * return -1 on failure. * return 0 on success. */ static int handle_packet_connection(Net_Crypto *c, int crypt_connection_id, uint8_t *packet, uint16_t length) { if (length == 0 || length > MAX_CRYPTO_PACKET_SIZE) return -1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; switch (packet[0]) { case NET_PACKET_COOKIE_RESPONSE: { if (conn->status != CRYPTO_CONN_COOKIE_REQUESTING) return -1; uint8_t cookie[COOKIE_LENGTH]; uint64_t number; if (handle_cookie_response(cookie, &number, packet, length, conn->shared_key) != sizeof(cookie)) return -1; if (number != conn->cookie_request_number) return -1; if (create_send_handshake(c, crypt_connection_id, cookie) != 0) return -1; conn->status = CRYPTO_CONN_HANDSHAKE_SENT; return 0; } case NET_PACKET_CRYPTO_HS: { if (conn->status == CRYPTO_CONN_COOKIE_REQUESTING || conn->status == CRYPTO_CONN_HANDSHAKE_SENT) { uint8_t peer_real_pk[crypto_box_PUBLICKEYBYTES]; uint8_t cookie[COOKIE_LENGTH]; if (handle_crypto_handshake(c, conn->recv_nonce, conn->peersessionpublic_key, peer_real_pk, cookie, packet, length, conn->public_key) != 0) return -1; encrypt_precompute(conn->peersessionpublic_key, conn->sessionsecret_key, conn->shared_key); if (conn->status == CRYPTO_CONN_COOKIE_REQUESTING) { if (create_send_handshake(c, crypt_connection_id, cookie) != 0) return -1; } conn->status = CRYPTO_CONN_NOT_CONFIRMED; } else { return -1; } return 0; } case NET_PACKET_CRYPTO_DATA: { if (conn->status == CRYPTO_CONN_NOT_CONFIRMED || conn->status == CRYPTO_CONN_ESTABLISHED) { return handle_data_packet_helper(c, crypt_connection_id, packet, length); } else { return -1; } return 0; } default: { return -1; } } return 0; } /* Set the size of the friend list to numfriends. * * return -1 if realloc fails. * return 0 if it succeeds. */ static int realloc_cryptoconnection(Net_Crypto *c, uint32_t num) { if (num == 0) { free(c->crypto_connections); c->crypto_connections = NULL; return 0; } Crypto_Connection *newcrypto_connections = realloc(c->crypto_connections, num * sizeof(Crypto_Connection)); if (newcrypto_connections == NULL) return -1; c->crypto_connections = newcrypto_connections; return 0; } /* Create a new empty crypto connection. * * return -1 on failure. * return connection id on success. */ static int create_crypto_connection(Net_Crypto *c) { uint32_t i; for (i = 0; i < c->crypto_connections_length; ++i) { if (c->crypto_connections[i].status == CRYPTO_CONN_NO_CONNECTION) return i; } if (realloc_cryptoconnection(c, c->crypto_connections_length + 1) == -1) return -1; memset(&(c->crypto_connections[c->crypto_connections_length]), 0, sizeof(Crypto_Connection)); int id = c->crypto_connections_length; ++c->crypto_connections_length; return id; } /* Wipe a crypto connection. * * return -1 on failure. * return 0 on success. */ static int wipe_crypto_connection(Net_Crypto *c, int crypt_connection_id) { if (crypt_connection_id_not_valid(c, crypt_connection_id)) return -1; uint32_t i; memset(&(c->crypto_connections[crypt_connection_id]), 0 , sizeof(Crypto_Connection)); for (i = c->crypto_connections_length; i != 0; --i) { if (c->crypto_connections[i - 1].status != CRYPTO_CONN_NO_CONNECTION) break; } if (c->crypto_connections_length != i) { c->crypto_connections_length = i; realloc_cryptoconnection(c, c->crypto_connections_length); } return 0; } /* Get crypto connection id from public key of peer. * * return -1 if there are no connections like we are looking for. * return id if it found it. */ static int getcryptconnection_id(Net_Crypto *c, uint8_t *public_key) { uint32_t i; for (i = 0; i < c->crypto_connections_length; ++i) { if (c->crypto_connections[i].status != CRYPTO_CONN_NO_CONNECTION) if (memcmp(public_key, c->crypto_connections[i].public_key, crypto_box_PUBLICKEYBYTES) == 0) return i; } return -1; } /* Add a source to the crypto connection. * This is to be used only when we have recieved a packet from that source. * * return -1 on failure. * return positive number on success. * 0 if source was a direct UDP connection. * TODO */ static int crypto_connection_add_source(Net_Crypto *c, int crypt_connection_id, IP_Port source) { Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; if (source.ip.family == AF_INET || source.ip.family == AF_INET6) { conn->ip_port = source; conn->direct_lastrecv_time = current_time_monotonic(); return 0; } return -1; } /* Set function to be called when someone requests a new connection to us. * * The set function should return -1 on failure and 0 on success. * * n_c is only valid for the duration of the function call. */ void new_connection_handler(Net_Crypto *c, int (*new_connection_callback)(void *object, New_Connection *n_c), void *object) { c->new_connection_callback = new_connection_callback; c->new_connection_callback_object = object; } /* Handle a handshake packet by someone who wants to initiate a new connection with us. * This calls the callback set by new_connection_handler() if the handshake is ok. * * return -1 on failure. * return 0 on success. */ static int handle_new_connection_handshake(Net_Crypto *c, IP_Port source, uint8_t *data, uint16_t length) { New_Connection n_c; n_c.cookie = malloc(COOKIE_LENGTH); if (n_c.cookie == NULL) return -1; n_c.source = source; n_c.cookie_length = COOKIE_LENGTH; if (handle_crypto_handshake(c, n_c.recv_nonce, n_c.peersessionpublic_key, n_c.public_key, n_c.cookie, data, length, 0) != 0) { free(n_c.cookie); return -1; } int crypt_connection_id = getcryptconnection_id(c, n_c.public_key); if (crypt_connection_id != -1) { int ret = -1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn != 0 && (conn->status == CRYPTO_CONN_COOKIE_REQUESTING || conn->status == CRYPTO_CONN_HANDSHAKE_SENT)) { memcpy(conn->recv_nonce, n_c.recv_nonce, crypto_box_NONCEBYTES); memcpy(conn->peersessionpublic_key, n_c.peersessionpublic_key, crypto_box_PUBLICKEYBYTES); encrypt_precompute(conn->peersessionpublic_key, conn->sessionsecret_key, conn->shared_key); crypto_connection_add_source(c, crypt_connection_id, source); if (create_send_handshake(c, crypt_connection_id, n_c.cookie) == 0) { conn->status = CRYPTO_CONN_NOT_CONFIRMED; ret = 0; } } free(n_c.cookie); return ret; } int ret = c->new_connection_callback(c->new_connection_callback_object, &n_c); free(n_c.cookie); return ret; } /* Accept a crypto connection. * * return -1 on failure. * return connection id on success. */ int accept_crypto_connection(Net_Crypto *c, New_Connection *n_c) { if (getcryptconnection_id(c, n_c->public_key) != -1) return -1; int crypt_connection_id = create_crypto_connection(c); if (crypt_connection_id == -1) return -1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; memcpy(conn->public_key, n_c->public_key, crypto_box_PUBLICKEYBYTES); memcpy(conn->recv_nonce, n_c->recv_nonce, crypto_box_NONCEBYTES); memcpy(conn->peersessionpublic_key, n_c->peersessionpublic_key, crypto_box_PUBLICKEYBYTES); random_nonce(conn->sent_nonce); crypto_box_keypair(conn->sessionpublic_key, conn->sessionsecret_key); encrypt_precompute(conn->peersessionpublic_key, conn->sessionsecret_key, conn->shared_key); if (n_c->cookie_length != COOKIE_LENGTH) return -1; if (create_send_handshake(c, crypt_connection_id, n_c->cookie) != 0) return -1; send_temp_packet(c, crypt_connection_id); conn->status = CRYPTO_CONN_NOT_CONFIRMED; crypto_connection_add_source(c, crypt_connection_id, n_c->source); return crypt_connection_id; } /* Create a crypto connection. * If one to that real public key already exists, return it. * * return -1 on failure. * return connection id on success. */ int new_crypto_connection(Net_Crypto *c, uint8_t *real_public_key) { int crypt_connection_id = getcryptconnection_id(c, real_public_key); if (crypt_connection_id != -1) return crypt_connection_id; crypt_connection_id = create_crypto_connection(c); if (crypt_connection_id == -1) return -1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; memcpy(conn->public_key, real_public_key, crypto_box_PUBLICKEYBYTES); random_nonce(conn->sent_nonce); crypto_box_keypair(conn->sessionpublic_key, conn->sessionsecret_key); conn->status = CRYPTO_CONN_COOKIE_REQUESTING; return crypt_connection_id; } /* Set the DHT public key of the crypto connection. * * return -1 on failure. * return 0 on success. */ int set_conection_dht_public_key(Net_Crypto *c, int crypt_connection_id, uint8_t *dht_public_key) { Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; if (conn->dht_public_key_set == 1 && memcmp(conn->dht_public_key, dht_public_key, crypto_box_PUBLICKEYBYTES) == 0) return -1; memcpy(conn->dht_public_key, dht_public_key, crypto_box_PUBLICKEYBYTES); conn->dht_public_key_set = 1; if (conn->status == CRYPTO_CONN_COOKIE_REQUESTING) { conn->cookie_request_number = random_64b(); uint8_t cookie_request[COOKIE_REQUEST_LENGTH]; if (create_cookie_request(c, cookie_request, conn->dht_public_key, conn->public_key, conn->cookie_request_number, conn->shared_key) != sizeof(cookie_request)) return -1; if (new_temp_packet(c, crypt_connection_id, cookie_request, sizeof(cookie_request)) != 0) return -1; }//TODO return 0; } /* Set the direct ip of the crypto connection. * * return -1 on failure. * return 0 on success. */ int set_direct_ip_port(Net_Crypto *c, int crypt_connection_id, IP_Port ip_port) { Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; if (!ipport_equal(&ip_port, &conn->ip_port)) { conn->ip_port = ip_port; conn->direct_lastrecv_time = 0; } return 0; } /* Set function to be called when connection with crypt_connection_id goes connects/disconnects. * * The set function should return -1 on failure and 0 on success. * Note that if this function is set, the connection will clear itself on disconnect. * Object and id will be passed to this function untouched. * status is 1 if the connection is going online, 0 if it is going offline. * * return -1 on failure. * return 0 on success. */ int connection_status_handler(Net_Crypto *c, int crypt_connection_id, int (*connection_status_callback)(void *object, int id, uint8_t status), void *object, int id) { Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; conn->connection_status_callback = connection_status_callback; conn->connection_status_callback_object = object; conn->connection_status_callback_id = id; return 0; } /* Set function to be called when connection with crypt_connection_id receives a data packet of length. * * The set function should return -1 on failure and 0 on success. * Object and id will be passed to this function untouched. * * return -1 on failure. * return 0 on success. */ int connection_data_handler(Net_Crypto *c, int crypt_connection_id, int (*connection_data_callback)(void *object, int id, uint8_t *data, uint16_t length), void *object, int id) { Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; conn->connection_data_callback = connection_data_callback; conn->connection_data_callback_object = object; conn->connection_data_callback_id = id; return 0; } /* Get the crypto connection id from the ip_port. * * return -1 on failure. * return connection id on success. */ static int crypto_id_ip_port(Net_Crypto *c, IP_Port ip_port) { uint32_t i; for (i = 0; i < c->crypto_connections_length; ++i) { if (is_alive(c->crypto_connections[i].status)) if (ipport_equal(&ip_port, &c->crypto_connections[i].ip_port)) return i; } return -1; } #define CRYPTO_MIN_PACKET_SIZE (1 + sizeof(uint16_t) + crypto_box_MACBYTES) /* Handle raw UDP packets coming directly from the socket. * * Handles: * Cookie response packets. * Crypto handshake packets. * Crypto data packets. * */ static int udp_handle_packet(void *object, IP_Port source, uint8_t *packet, uint32_t length) { if (length <= CRYPTO_MIN_PACKET_SIZE || length > MAX_CRYPTO_PACKET_SIZE) return 1; Net_Crypto *c = object; int crypt_connection_id = crypto_id_ip_port(c, source); if (crypt_connection_id == -1) { if (packet[0] != NET_PACKET_CRYPTO_HS) return 1; if (handle_new_connection_handshake(c, source, packet, length) != 0) return 1; return 0; } if (handle_packet_connection(c, crypt_connection_id, packet, length) != 0) return 1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; conn->direct_lastrecv_time = current_time_monotonic(); return 0; } static void send_crypto_packets(Net_Crypto *c) { uint32_t i; uint64_t temp_time = current_time_monotonic(); for (i = 0; i < c->crypto_connections_length; ++i) { Crypto_Connection *conn = get_crypto_connection(c, i); if (conn == 0) return; if (CRYPTO_SEND_PACKET_INTERVAL + conn->temp_packet_sent_time < temp_time) { send_temp_packet(c, i); } if (conn->status >= CRYPTO_CONN_NOT_CONFIRMED && (500ULL + conn->last_data_packet_sent) < temp_time) {//TODO remove this. uint8_t data[4] = {5, 2}; send_lossless_packet(c, i, data, 4); } } } /* returns the number of packet slots left in the sendbuffer. * return 0 if failure. */ uint32_t crypto_num_free_sendqueue_slots(Net_Crypto *c, int crypt_connection_id) { Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return 0; //TODO return CRYPTO_PACKET_BUFFER_SIZE - num_packets_array(&conn->send_array); } /* return -1 if data could not be put in packet queue. * return positive packet number if data was put into the queue. */ int64_t write_cryptpacket(Net_Crypto *c, int crypt_connection_id, uint8_t *data, uint32_t length) { if (length == 0) return -1; if (data[0] < CRYPTO_RESERVED_PACKETS) return -1; Crypto_Connection *conn = get_crypto_connection(c, crypt_connection_id); if (conn == 0) return -1; if (conn->status != CRYPTO_CONN_ESTABLISHED) return -1; return send_lossless_packet(c, crypt_connection_id, data, length); } /* Kill a crypto connection. * * return -1 on failure. * return 0 on success. */ int crypto_kill(Net_Crypto *c, int crypt_connection_id) { //TODO return wipe_crypto_connection(c, crypt_connection_id); } /* return 0 if no connection. * return 1 we have sent a handshake. * return 2 if connection is not confirmed yet (we have received a handshake but no empty data packet). * return 3 if the connection is established. * return 4 if the connection is timed out and waiting to be killed. */ int is_cryptoconnected(Net_Crypto *c, int crypt_connection_id) { if ((unsigned int)crypt_connection_id < c->crypto_connections_length) return c->crypto_connections[crypt_connection_id].status; return CRYPTO_CONN_NO_CONNECTION; } void new_keys(Net_Crypto *c) { crypto_box_keypair(c->self_public_key, c->self_secret_key); } /* Save the public and private keys to the keys array. * Length must be crypto_box_PUBLICKEYBYTES + crypto_box_SECRETKEYBYTES. */ void save_keys(Net_Crypto *c, uint8_t *keys) { memcpy(keys, c->self_public_key, crypto_box_PUBLICKEYBYTES); memcpy(keys + crypto_box_PUBLICKEYBYTES, c->self_secret_key, crypto_box_SECRETKEYBYTES); } /* Load the public and private keys from the keys array. * Length must be crypto_box_PUBLICKEYBYTES + crypto_box_SECRETKEYBYTES. */ void load_keys(Net_Crypto *c, uint8_t *keys) { memcpy(c->self_public_key, keys, crypto_box_PUBLICKEYBYTES); memcpy(c->self_secret_key, keys + crypto_box_PUBLICKEYBYTES, crypto_box_SECRETKEYBYTES); } /* Run this to (re)initialize net_crypto. * Sets all the global connection variables to their default values. */ Net_Crypto *new_net_crypto(DHT *dht) { unix_time_update(); if (dht == NULL) return NULL; Net_Crypto *temp = calloc(1, sizeof(Net_Crypto)); if (temp == NULL) return NULL; temp->dht = dht; new_keys(temp); new_symmetric_key(temp->secret_symmetric_key); networking_registerhandler(dht->net, NET_PACKET_COOKIE_REQUEST, &udp_handle_cookie_request, temp); networking_registerhandler(dht->net, NET_PACKET_COOKIE_RESPONSE, &udp_handle_packet, temp); networking_registerhandler(dht->net, NET_PACKET_CRYPTO_HS, &udp_handle_packet, temp); networking_registerhandler(dht->net, NET_PACKET_CRYPTO_DATA, &udp_handle_packet, temp); return temp; } static void kill_timedout(Net_Crypto *c) { uint32_t i; //uint64_t temp_time = current_time_monotonic(); for (i = 0; i < c->crypto_connections_length; ++i) { Crypto_Connection *conn = get_crypto_connection(c, i); if (conn == 0) return; if (conn->status == CRYPTO_CONN_NO_CONNECTION || conn->status == CRYPTO_CONN_TIMED_OUT) continue; if (conn->status == CRYPTO_CONN_COOKIE_REQUESTING || conn->status == CRYPTO_CONN_HANDSHAKE_SENT || conn->status == CRYPTO_CONN_NOT_CONFIRMED) { if (conn->temp_packet_num_sent < MAX_NUM_SENDPACKET_TRIES) continue; if (conn->connection_status_callback) { conn->connection_status_callback(conn->connection_status_callback_object, conn->connection_status_callback_id, 0); crypto_kill(c, i); continue; } conn->status = CRYPTO_CONN_TIMED_OUT; continue; } if (conn->status == CRYPTO_CONN_ESTABLISHED) { //TODO: add a timeout here? } } } /* Main loop. */ void do_net_crypto(Net_Crypto *c) { unix_time_update(); kill_timedout(c); send_crypto_packets(c); } void kill_net_crypto(Net_Crypto *c) { uint32_t i; for (i = 0; i < c->crypto_connections_length; ++i) { crypto_kill(c, i); } networking_registerhandler(c->dht->net, NET_PACKET_COOKIE_REQUEST, NULL, NULL); networking_registerhandler(c->dht->net, NET_PACKET_COOKIE_RESPONSE, NULL, NULL); networking_registerhandler(c->dht->net, NET_PACKET_CRYPTO_HS, NULL, NULL); networking_registerhandler(c->dht->net, NET_PACKET_CRYPTO_DATA, NULL, NULL); memset(c, 0, sizeof(Net_Crypto)); free(c); }