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toxcore/toxcore/net_crypto.c
irungentoo e95494482f A bit of work done on the TCP relay server.
2014-03-15 22:11:36 -04:00

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/* 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 <http://www.gnu.org/licenses/>.
*
*/
#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;
}
/* Use this instead of memcmp; not vulnerable to timing attacks. */
uint8_t crypto_iszero(uint8_t *mem, uint32_t length)
{
uint8_t check = 0;
uint32_t i;
for (i = 0; i < length; ++i) {
check |= mem[i];
}
return check; // We return zero if mem is made out of zeroes.
}
/* Precomputes the shared key from their public_key and our secret_key.
* This way we can avoid an expensive elliptic curve scalar multiply for each
* encrypt/decrypt operation.
* enc_key has to be crypto_box_BEFORENMBYTES bytes long.
*/
void encrypt_precompute(uint8_t *public_key, uint8_t *secret_key, uint8_t *enc_key)
{
crypto_box_beforenm(enc_key, public_key, secret_key);
}
/* Fast encrypt. Depends on enc_key from encrypt_precompute. */
int encrypt_data_fast(uint8_t *enc_key, uint8_t *nonce,
uint8_t *plain, uint32_t length, uint8_t *encrypted)
{
if (length + crypto_box_MACBYTES > MAX_DATA_SIZE || length == 0)
return -1;
uint8_t temp_plain[MAX_DATA_SIZE + crypto_box_ZEROBYTES] = {0};
uint8_t temp_encrypted[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES];
memcpy(temp_plain + crypto_box_ZEROBYTES, plain, length); // Pad the message with 32 0 bytes.
crypto_box_afternm(temp_encrypted, temp_plain, length + crypto_box_ZEROBYTES, nonce, enc_key);
if (crypto_iszero(temp_encrypted, crypto_box_BOXZEROBYTES) != 0)
return -1;
/* Unpad the encrypted message. */
memcpy(encrypted, temp_encrypted + crypto_box_BOXZEROBYTES, length + crypto_box_MACBYTES);
return length + crypto_box_MACBYTES;
}
/* Fast decrypt. Depends on enc_ley from encrypt_precompute. */
int decrypt_data_fast(uint8_t *enc_key, uint8_t *nonce,
uint8_t *encrypted, uint32_t length, uint8_t *plain)
{
if (length > MAX_DATA_SIZE || length <= crypto_box_BOXZEROBYTES)
return -1;
uint8_t temp_plain[MAX_DATA_SIZE + crypto_box_ZEROBYTES];
uint8_t temp_encrypted[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES] = {0};
memcpy(temp_encrypted + crypto_box_BOXZEROBYTES, encrypted, length); // Pad the message with 16 0 bytes.
if (crypto_box_open_afternm(temp_plain, temp_encrypted, length + crypto_box_BOXZEROBYTES,
nonce, enc_key) == -1)
return -1;
/* If decryption is successful the first crypto_box_ZEROBYTES of the message will be zero.
* Apparently memcmp should not be used so we do this instead:
*/
if (crypto_iszero(temp_plain, crypto_box_ZEROBYTES) != 0)
return -1;
/* Unpad the plain message. */
memcpy(plain, temp_plain + crypto_box_ZEROBYTES, length - crypto_box_MACBYTES);
return length - crypto_box_MACBYTES;
}
int encrypt_data(uint8_t *public_key, uint8_t *secret_key, uint8_t *nonce,
uint8_t *plain, uint32_t length, uint8_t *encrypted)
{
uint8_t k[crypto_box_BEFORENMBYTES];
encrypt_precompute(public_key, secret_key, k);
return encrypt_data_fast(k, nonce, plain, length, encrypted);
}
int decrypt_data(uint8_t *public_key, uint8_t *secret_key, uint8_t *nonce,
uint8_t *encrypted, uint32_t length, uint8_t *plain)
{
uint8_t k[crypto_box_BEFORENMBYTES];
encrypt_precompute(public_key, secret_key, k);
return decrypt_data_fast(k, nonce, encrypted, length, plain);
}
int encrypt_data_symmetric(uint8_t *secret_key, uint8_t *nonce, uint8_t *plain, uint32_t length, uint8_t *encrypted)
{
if (length == 0)
return -1;
uint8_t temp_plain[length + crypto_secretbox_ZEROBYTES];
uint8_t temp_encrypted[length + crypto_secretbox_MACBYTES + crypto_secretbox_BOXZEROBYTES];
memset(temp_plain, 0, crypto_secretbox_ZEROBYTES);
memcpy(temp_plain + crypto_secretbox_ZEROBYTES, plain, length); // Pad the message with 32 0 bytes.
crypto_secretbox(temp_encrypted, temp_plain, length + crypto_secretbox_ZEROBYTES, nonce, secret_key);
/* Unpad the encrypted message. */
memcpy(encrypted, temp_encrypted + crypto_secretbox_BOXZEROBYTES, length + crypto_secretbox_MACBYTES);
return length + crypto_secretbox_MACBYTES;
}
int decrypt_data_symmetric(uint8_t *secret_key, uint8_t *nonce, uint8_t *encrypted, uint32_t length, uint8_t *plain)
{
if (length <= crypto_secretbox_BOXZEROBYTES)
return -1;
uint8_t temp_plain[length + crypto_secretbox_ZEROBYTES];
uint8_t temp_encrypted[length + crypto_secretbox_BOXZEROBYTES];
memset(temp_plain, 0, crypto_secretbox_BOXZEROBYTES);
memcpy(temp_encrypted + crypto_secretbox_BOXZEROBYTES, encrypted, length); // Pad the message with 16 0 bytes.
if (crypto_secretbox_open(temp_plain, temp_encrypted, length + crypto_secretbox_BOXZEROBYTES, nonce, secret_key) == -1)
return -1;
memcpy(plain, temp_plain + crypto_secretbox_ZEROBYTES, length - crypto_secretbox_MACBYTES);
return length - crypto_secretbox_MACBYTES;
}
/* Increment the given nonce by 1. */
void increment_nonce(uint8_t *nonce)
{
uint32_t i;
for (i = 0; i < crypto_box_NONCEBYTES; ++i) {
++nonce[i];
if (nonce[i] != 0)
break;
}
}
#if crypto_box_NONCEBYTES != crypto_secretbox_NONCEBYTES
/*if they no longer equal each other, this function must be split into two.*/
#error random_nonce(): crypto_box_NONCEBYTES must equal crypto_secretbox_NONCEBYTES.
#endif
/* Fill the given nonce with random bytes. */
void random_nonce(uint8_t *nonce)
{
randombytes(nonce, crypto_box_NONCEBYTES);
}
/* Fill a key crypto_secretbox_KEYBYTES big with random bytes */
void new_symmetric_key(uint8_t *key)
{
randombytes(key, crypto_secretbox_KEYBYTES);
}
static uint8_t base_nonce[crypto_box_NONCEBYTES];
static uint8_t nonce_set = 0;
#if crypto_box_NONCEBYTES != crypto_secretbox_NONCEBYTES
/*if they no longer equal each other, this function must be split into two.*/
#error new_nonce(): crypto_box_NONCEBYTES must equal crypto_secretbox_NONCEBYTES.
#endif
/* Gives a nonce guaranteed to be different from previous ones.*/
void new_nonce(uint8_t *nonce)
{
if (nonce_set == 0) {
random_nonce(base_nonce);
nonce_set = 1;
}
increment_nonce(base_nonce);
memcpy(nonce, base_nonce, crypto_box_NONCEBYTES);
}
/* return 0 if there is no received data in the buffer.
* return -1 if the packet was discarded.
* return length of received data if successful.
*/
int read_cryptpacket(Net_Crypto *c, int crypt_connection_id, uint8_t *data)
{
if (crypt_connection_id_not_valid(c, crypt_connection_id))
return 0;
if (c->crypto_connections[crypt_connection_id].status != CRYPTO_CONN_ESTABLISHED)
return 0;
uint8_t temp_data[MAX_DATA_SIZE];
int length = read_packet(c->lossless_udp, c->crypto_connections[crypt_connection_id].number, temp_data);
if (length == 0)
return 0;
if (temp_data[0] != 3)
return -1;
int len = decrypt_data_fast(c->crypto_connections[crypt_connection_id].shared_key,
c->crypto_connections[crypt_connection_id].recv_nonce,
temp_data + 1, length - 1, data);
if (len != -1) {
increment_nonce(c->crypto_connections[crypt_connection_id].recv_nonce);
return len;
}
return -1;
}
/* 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)
{
if (crypt_connection_id_not_valid(c, crypt_connection_id))
return 0;
return num_free_sendqueue_slots(c->lossless_udp, c->crypto_connections[crypt_connection_id].number);
}
/* return 0 if data could not be put in packet queue.
* return 1 if data was put into the queue.
*/
int write_cryptpacket(Net_Crypto *c, int crypt_connection_id, uint8_t *data, uint32_t length)
{
if (crypt_connection_id_not_valid(c, crypt_connection_id))
return 0;
if (length - crypto_box_BOXZEROBYTES + crypto_box_ZEROBYTES > MAX_DATA_SIZE - 1)
return 0;
if (c->crypto_connections[crypt_connection_id].status != CRYPTO_CONN_ESTABLISHED)
return 0;
uint8_t temp_data[MAX_DATA_SIZE];
int len = encrypt_data_fast(c->crypto_connections[crypt_connection_id].shared_key,
c->crypto_connections[crypt_connection_id].sent_nonce,
data, length, temp_data + 1);
if (len == -1)
return 0;
temp_data[0] = 3;
if (write_packet(c->lossless_udp, c->crypto_connections[crypt_connection_id].number, temp_data, len + 1) == 0)
return 0;
increment_nonce(c->crypto_connections[crypt_connection_id].sent_nonce);
return 1;
}
/* Create a request to peer.
* send_public_key and send_secret_key are the pub/secret keys of the sender.
* recv_public_key is public key of reciever.
* packet must be an array of MAX_DATA_SIZE big.
* Data represents the data we send with the request with length being the length of the data.
* request_id is the id of the request (32 = friend request, 254 = ping request).
*
* return -1 on failure.
* return the length of the created packet on success.
*/
int create_request(uint8_t *send_public_key, uint8_t *send_secret_key, uint8_t *packet, uint8_t *recv_public_key,
uint8_t *data, uint32_t length, uint8_t request_id)
{
if (MAX_DATA_SIZE < length + 1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1 + crypto_box_MACBYTES)
return -1;
uint8_t nonce[crypto_box_NONCEBYTES];
uint8_t temp[MAX_DATA_SIZE];
memcpy(temp + 1, data, length);
temp[0] = request_id;
new_nonce(nonce);
int len = encrypt_data(recv_public_key, send_secret_key, nonce, temp, length + 1,
1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + packet);
if (len == -1)
return -1;
packet[0] = NET_PACKET_CRYPTO;
memcpy(packet + 1, recv_public_key, crypto_box_PUBLICKEYBYTES);
memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES, send_public_key, crypto_box_PUBLICKEYBYTES);
memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES * 2, nonce, crypto_box_NONCEBYTES);
return len + 1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES;
}
/* Puts the senders public key in the request in public_key, the data from the request
* in data if a friend or ping request was sent to us and returns the length of the data.
* packet is the request packet and length is its length.
*
* return -1 if not valid request.
*/
int handle_request(uint8_t *self_public_key, uint8_t *self_secret_key, uint8_t *public_key, uint8_t *data,
uint8_t *request_id, uint8_t *packet, uint16_t length)
{
if (length > crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1 + crypto_box_MACBYTES &&
length <= MAX_DATA_SIZE) {
if (memcmp(packet + 1, self_public_key, crypto_box_PUBLICKEYBYTES) == 0) {
memcpy(public_key, packet + 1 + crypto_box_PUBLICKEYBYTES, crypto_box_PUBLICKEYBYTES);
uint8_t nonce[crypto_box_NONCEBYTES];
uint8_t temp[MAX_DATA_SIZE];
memcpy(nonce, packet + 1 + crypto_box_PUBLICKEYBYTES * 2, crypto_box_NONCEBYTES);
int len1 = decrypt_data(public_key, self_secret_key, nonce,
packet + 1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES,
length - (crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1), temp);
if (len1 == -1 || len1 == 0)
return -1;
request_id[0] = temp[0];
--len1;
memcpy(data, temp + 1, len1);
return len1;
}
}
return -1;
}
void cryptopacket_registerhandler(Net_Crypto *c, uint8_t byte, cryptopacket_handler_callback cb, void *object)
{
c->cryptopackethandlers[byte].function = cb;
c->cryptopackethandlers[byte].object = object;
}
static int cryptopacket_handle(void *object, IP_Port source, uint8_t *packet, uint32_t length)
{
DHT *dht = object;
if (packet[0] == NET_PACKET_CRYPTO) {
if (length <= crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1 + crypto_box_MACBYTES ||
length > MAX_DATA_SIZE + crypto_box_MACBYTES)
return 1;
if (memcmp(packet + 1, dht->self_public_key, crypto_box_PUBLICKEYBYTES) == 0) { // Check if request is for us.
uint8_t public_key[crypto_box_PUBLICKEYBYTES];
uint8_t data[MAX_DATA_SIZE];
uint8_t number;
int len = handle_request(dht->self_public_key, dht->self_secret_key, public_key, data, &number, packet, length);
if (len == -1 || len == 0)
return 1;
if (!dht->c->cryptopackethandlers[number].function) return 1;
return dht->c->cryptopackethandlers[number].function(dht->c->cryptopackethandlers[number].object, source, public_key,
data, len);
} else { /* If request is not for us, try routing it. */
int retval = route_packet(dht, packet + 1, packet, length);
if ((unsigned int)retval == length)
return 0;
}
}
return 1;
}
/* Send a crypto handshake packet containing an encrypted secret nonce and session public key
* to peer with connection_id and public_key.
* The packet is encrypted with a random nonce which is sent in plain text with the packet.
*/
static int send_cryptohandshake(Net_Crypto *c, int connection_id, uint8_t *public_key, uint8_t *secret_nonce,
uint8_t *session_key)
{
uint8_t temp_data[MAX_DATA_SIZE];
uint8_t temp[crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES];
uint8_t nonce[crypto_box_NONCEBYTES];
new_nonce(nonce);
memcpy(temp, secret_nonce, crypto_box_NONCEBYTES);
memcpy(temp + crypto_box_NONCEBYTES, session_key, crypto_box_PUBLICKEYBYTES);
int len = encrypt_data(public_key, c->self_secret_key, nonce, temp, crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES,
1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + temp_data);
if (len == -1)
return 0;
temp_data[0] = 2;
memcpy(temp_data + 1, c->self_public_key, crypto_box_PUBLICKEYBYTES);
memcpy(temp_data + 1 + crypto_box_PUBLICKEYBYTES, nonce, crypto_box_NONCEBYTES);
return write_packet(c->lossless_udp, connection_id, temp_data,
len + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES);
}
/* Extract secret nonce, session public key and public_key from a packet(data) with length length.
*
* return 1 if successful.
* return 0 if failure.
*/
static int handle_cryptohandshake(Net_Crypto *c, uint8_t *public_key, uint8_t *secret_nonce,
uint8_t *session_key, uint8_t *data, uint16_t length)
{
int pad = (- crypto_box_BOXZEROBYTES + crypto_box_ZEROBYTES);
if (length != 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES
+ crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + pad) {
return 0;
}
if (data[0] != 2)
return 0;
uint8_t temp[crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES];
memcpy(public_key, data + 1, crypto_box_PUBLICKEYBYTES);
int len = decrypt_data(public_key, c->self_secret_key, data + 1 + crypto_box_PUBLICKEYBYTES,
data + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES,
crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + pad, temp);
if (len != crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES)
return 0;
memcpy(secret_nonce, temp, crypto_box_NONCEBYTES);
memcpy(session_key, temp + crypto_box_NONCEBYTES, crypto_box_PUBLICKEYBYTES);
return 1;
}
/* 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;
}
/* 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;
}
/* Start a secure connection with other peer who has public_key and ip_port.
*
* return -1 if failure.
* return crypt_connection_id of the initialized connection if everything went well.
*/
int crypto_connect(Net_Crypto *c, uint8_t *public_key, IP_Port ip_port)
{
uint32_t i;
int id_existing = getcryptconnection_id(c, public_key);
if (id_existing != -1) {
IP_Port c_ip = connection_ip(c->lossless_udp, c->crypto_connections[id_existing].number);
if (ipport_equal(&c_ip, &ip_port))
return -1;
}
if (realloc_cryptoconnection(c, c->crypto_connections_length + 1) == -1
|| c->crypto_connections == NULL)
return -1;
memset(&(c->crypto_connections[c->crypto_connections_length]), 0, sizeof(Crypto_Connection));
c->crypto_connections[c->crypto_connections_length].number = ~0;
for (i = 0; i <= c->crypto_connections_length; ++i) {
if (c->crypto_connections[i].status == CRYPTO_CONN_NO_CONNECTION) {
int id_new = new_connection(c->lossless_udp, ip_port);
if (id_new == -1)
return -1;
c->crypto_connections[i].number = id_new;
c->crypto_connections[i].status = CRYPTO_CONN_HANDSHAKE_SENT;
random_nonce(c->crypto_connections[i].recv_nonce);
memcpy(c->crypto_connections[i].public_key, public_key, crypto_box_PUBLICKEYBYTES);
crypto_box_keypair(c->crypto_connections[i].sessionpublic_key, c->crypto_connections[i].sessionsecret_key);
c->crypto_connections[i].timeout = unix_time() + CRYPTO_HANDSHAKE_TIMEOUT;
if (c->crypto_connections_length == i)
++c->crypto_connections_length;
if (send_cryptohandshake(c, id_new, public_key, c->crypto_connections[i].recv_nonce,
c->crypto_connections[i].sessionpublic_key) == 1) {
increment_nonce(c->crypto_connections[i].recv_nonce);
return i;
}
return -1; /* This should never happen. */
}
}
return -1;
}
/* Handle an incoming connection.
*
* return -1 if no crypto inbound connection.
* return incoming connection id (Lossless_UDP one) if there is an incoming crypto connection.
*
* Put the public key of the peer in public_key, the secret_nonce from the handshake into secret_nonce
* and the session public key for the connection in session_key.
* to accept it see: accept_crypto_inbound(...).
* to refuse it just call kill_connection(...) on the connection id.
*/
int crypto_inbound(Net_Crypto *c, uint8_t *public_key, uint8_t *secret_nonce, uint8_t *session_key)
{
while (1) {
int incoming_con = incoming_connection(c->lossless_udp, 1);
if (incoming_con != -1) {
if (is_connected(c->lossless_udp, incoming_con) == LUDP_TIMED_OUT) {
kill_connection(c->lossless_udp, incoming_con);
continue;
}
if (id_packet(c->lossless_udp, incoming_con) == 2) {
uint8_t temp_data[MAX_DATA_SIZE];
uint16_t len = read_packet_silent(c->lossless_udp, incoming_con, temp_data);
if (handle_cryptohandshake(c, public_key, secret_nonce, session_key, temp_data, len)) {
return incoming_con;
} else {
kill_connection(c->lossless_udp, incoming_con);
}
} else {
kill_connection(c->lossless_udp, incoming_con);
}
} else {
break;
}
}
return -1;
}
/* Kill a crypto connection.
*
* return 0 if killed successfully.
* return 1 if there was a problem.
*/
int crypto_kill(Net_Crypto *c, int crypt_connection_id)
{
if (crypt_connection_id_not_valid(c, crypt_connection_id))
return 1;
if (c->crypto_connections[crypt_connection_id].status != CRYPTO_CONN_NO_CONNECTION) {
c->crypto_connections[crypt_connection_id].status = CRYPTO_CONN_NO_CONNECTION;
kill_connection(c->lossless_udp, c->crypto_connections[crypt_connection_id].number);
memset(&(c->crypto_connections[crypt_connection_id]), 0 , sizeof(Crypto_Connection));
c->crypto_connections[crypt_connection_id].number = ~0;
uint32_t i;
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;
}
return 1;
}
/* Accept an incoming connection using the parameters provided by crypto_inbound.
*
* return -1 if not successful.
* return the crypt_connection_id if successful.
*/
int accept_crypto_inbound(Net_Crypto *c, int connection_id, uint8_t *public_key, uint8_t *secret_nonce,
uint8_t *session_key)
{
uint32_t i;
if (discard_packet(c->lossless_udp, connection_id) == -1)
return -1;
/*
* if(getcryptconnection_id(public_key) != -1)
* {
* return -1;
* }
*/
if (realloc_cryptoconnection(c, c->crypto_connections_length + 1) == -1
|| c->crypto_connections == NULL)
return -1;
memset(&(c->crypto_connections[c->crypto_connections_length]), 0, sizeof(Crypto_Connection));
c->crypto_connections[c->crypto_connections_length].number = ~0;
for (i = 0; i <= c->crypto_connections_length; ++i) {
if (c->crypto_connections[i].status == CRYPTO_CONN_NO_CONNECTION) {
c->crypto_connections[i].number = connection_id;
c->crypto_connections[i].status = CRYPTO_CONN_NOT_CONFIRMED;
c->crypto_connections[i].timeout = unix_time() + CRYPTO_HANDSHAKE_TIMEOUT;
random_nonce(c->crypto_connections[i].recv_nonce);
memcpy(c->crypto_connections[i].sent_nonce, secret_nonce, crypto_box_NONCEBYTES);
memcpy(c->crypto_connections[i].peersessionpublic_key, session_key, crypto_box_PUBLICKEYBYTES);
increment_nonce(c->crypto_connections[i].sent_nonce);
memcpy(c->crypto_connections[i].public_key, public_key, crypto_box_PUBLICKEYBYTES);
crypto_box_keypair(c->crypto_connections[i].sessionpublic_key, c->crypto_connections[i].sessionsecret_key);
if (c->crypto_connections_length == i)
++c->crypto_connections_length;
if (send_cryptohandshake(c, connection_id, public_key, c->crypto_connections[i].recv_nonce,
c->crypto_connections[i].sessionpublic_key) == 1) {
increment_nonce(c->crypto_connections[i].recv_nonce);
uint32_t zero = 0;
encrypt_precompute(c->crypto_connections[i].peersessionpublic_key,
c->crypto_connections[i].sessionsecret_key,
c->crypto_connections[i].shared_key);
c->crypto_connections[i].status =
CRYPTO_CONN_ESTABLISHED; /* Connection status needs to be 3 for write_cryptpacket() to work. */
write_cryptpacket(c, i, ((uint8_t *)&zero), sizeof(zero));
c->crypto_connections[i].status = CRYPTO_CONN_NOT_CONFIRMED; /* Set it to its proper value right after. */
return i;
}
return -1; /* This should never happen. */
}
}
return -1;
}
/* 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);
}
/* Handle received packets for not yet established crypto connections. */
static void receive_crypto(Net_Crypto *c)
{
uint32_t i;
uint64_t temp_time = unix_time();
for (i = 0; i < c->crypto_connections_length; ++i) {
if (c->crypto_connections[i].status == CRYPTO_CONN_NO_CONNECTION)
continue;
if (c->crypto_connections[i].status == CRYPTO_CONN_HANDSHAKE_SENT) {
uint8_t temp_data[MAX_DATA_SIZE];
uint8_t secret_nonce[crypto_box_NONCEBYTES];
uint8_t public_key[crypto_box_PUBLICKEYBYTES];
uint8_t session_key[crypto_box_PUBLICKEYBYTES];
uint16_t len;
if (id_packet(c->lossless_udp, c->crypto_connections[i].number) == 2) { /* Handle handshake packet. */
len = read_packet(c->lossless_udp, c->crypto_connections[i].number, temp_data);
if (handle_cryptohandshake(c, public_key, secret_nonce, session_key, temp_data, len)) {
if (memcmp(public_key, c->crypto_connections[i].public_key, crypto_box_PUBLICKEYBYTES) == 0) {
memcpy(c->crypto_connections[i].sent_nonce, secret_nonce, crypto_box_NONCEBYTES);
memcpy(c->crypto_connections[i].peersessionpublic_key, session_key, crypto_box_PUBLICKEYBYTES);
increment_nonce(c->crypto_connections[i].sent_nonce);
uint32_t zero = 0;
encrypt_precompute(c->crypto_connections[i].peersessionpublic_key,
c->crypto_connections[i].sessionsecret_key,
c->crypto_connections[i].shared_key);
c->crypto_connections[i].status =
CRYPTO_CONN_ESTABLISHED; /* Connection status needs to be 3 for write_cryptpacket() to work. */
write_cryptpacket(c, i, ((uint8_t *)&zero), sizeof(zero));
c->crypto_connections[i].status = CRYPTO_CONN_NOT_CONFIRMED; /* Set it to its proper value right after. */
} else {
/* This should not happen, timeout the connection if it does. */
c->crypto_connections[i].status = CRYPTO_CONN_TIMED_OUT;
}
} else {
/* This should not happen, timeout the connection if it does. */
c->crypto_connections[i].status = CRYPTO_CONN_TIMED_OUT;
}
} else if (id_packet(c->lossless_udp,
c->crypto_connections[i].number) != (uint8_t)~0) {
/* This should not happen, timeout the connection if it does. */
c->crypto_connections[i].status = CRYPTO_CONN_TIMED_OUT;
}
}
if (c->crypto_connections[i].status == CRYPTO_CONN_NOT_CONFIRMED) {
if (id_packet(c->lossless_udp, c->crypto_connections[i].number) == 3) {
uint8_t temp_data[MAX_DATA_SIZE];
uint8_t data[MAX_DATA_SIZE];
int length = read_packet(c->lossless_udp, c->crypto_connections[i].number, temp_data);
int len = decrypt_data(c->crypto_connections[i].peersessionpublic_key,
c->crypto_connections[i].sessionsecret_key,
c->crypto_connections[i].recv_nonce, temp_data + 1, length - 1, data);
uint32_t zero = 0;
if (len == sizeof(uint32_t) && memcmp(((uint8_t *)&zero), data, sizeof(uint32_t)) == 0) {
increment_nonce(c->crypto_connections[i].recv_nonce);
encrypt_precompute(c->crypto_connections[i].peersessionpublic_key,
c->crypto_connections[i].sessionsecret_key,
c->crypto_connections[i].shared_key);
c->crypto_connections[i].status = CRYPTO_CONN_ESTABLISHED;
c->crypto_connections[i].timeout = ~0;
/* Connection is accepted. */
confirm_connection(c->lossless_udp, c->crypto_connections[i].number);
} else {
/* This should not happen, timeout the connection if it does. */
c->crypto_connections[i].status = CRYPTO_CONN_TIMED_OUT;
}
} else if (id_packet(c->lossless_udp, c->crypto_connections[i].number) != (uint8_t)~0) {
/* This should not happen, timeout the connection if it does. */
c->crypto_connections[i].status = CRYPTO_CONN_TIMED_OUT;
}
}
if (temp_time > c->crypto_connections[i].timeout) {
c->crypto_connections[i].status = CRYPTO_CONN_TIMED_OUT;
}
}
}
/* Run this to (re)initialize net_crypto.
* Sets all the global connection variables to their default values.
*/
Net_Crypto *new_net_crypto(Networking_Core *net)
{
unix_time_update();
if (net == NULL)
return NULL;
Net_Crypto *temp = calloc(1, sizeof(Net_Crypto));
if (temp == NULL)
return NULL;
temp->lossless_udp = new_lossless_udp(net);
if (temp->lossless_udp == NULL) {
free(temp);
return NULL;
}
new_keys(temp);
return temp;
}
void init_cryptopackets(void *dht)
{
DHT *s_dht = dht;
networking_registerhandler(s_dht->c->lossless_udp->net, NET_PACKET_CRYPTO, &cryptopacket_handle, s_dht);
}
static void kill_timedout(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
&& is_connected(c->lossless_udp, c->crypto_connections[i].number) == LUDP_TIMED_OUT)
c->crypto_connections[i].status = CRYPTO_CONN_TIMED_OUT;
}
}
/* Main loop. */
void do_net_crypto(Net_Crypto *c)
{
unix_time_update();
do_lossless_udp(c->lossless_udp);
kill_timedout(c);
receive_crypto(c);
}
void kill_net_crypto(Net_Crypto *c)
{
uint32_t i;
for (i = 0; i < c->crypto_connections_length; ++i) {
crypto_kill(c, i);
}
kill_lossless_udp(c->lossless_udp);
memset(c, 0, sizeof(Net_Crypto));
free(c);
}
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