StarMirror/toxcore
1
0
Fork 0
mirror of https://github.com/irungentoo/toxcore.git synced 2024-03-22 13:30:51 +08:00
Code Issues Projects Releases Wiki Activity
8a56f9cb37
toxcore/core/net_crypto.c
irungentoo 4330bfbf87 Metadata collection prevention part 1 of ???. 
Crypto requests packets are packets that can be routed by nodes in the
DHT. In this pull request I have merged both Natping requests and friend
requests into one common packet (Crypto request packets). Both these
packets should now only be distinguishable by the size of the data in
them to an outside observer for an example on how to send and recieve
data with these packets see: friend_requests.c

Note that these packets are prefixed with id 32 (friend request packets)
which means this change is compatible with the currently running DHT
bootstrap servers.

Also changed small thing in DHT_test.c
2013-08-14 18:26:00 -04:00

649 lines
27 KiB
C
Raw Blame History

/* 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/>.
*
*/
#include "net_crypto.h"
/* Our public and secret keys. */
uint8_t self_public_key[crypto_box_PUBLICKEYBYTES];
uint8_t self_secret_key[crypto_box_SECRETKEYBYTES];
typedef struct {
uint8_t public_key[crypto_box_PUBLICKEYBYTES]; /* the real public key of the peer. */
uint8_t recv_nonce[crypto_box_NONCEBYTES]; /* nonce of received packets */
uint8_t sent_nonce[crypto_box_NONCEBYTES]; /* nonce of sent packets. */
uint8_t sessionpublic_key[crypto_box_PUBLICKEYBYTES]; /* our public key for this session. */
uint8_t sessionsecret_key[crypto_box_SECRETKEYBYTES]; /* our private key for this session. */
uint8_t peersessionpublic_key[crypto_box_PUBLICKEYBYTES]; /* The public key of the peer. */
uint8_t shared_key[crypto_box_BEFORENMBYTES]; /* the precomputed shared key from encrypt_precompute */
uint8_t status; /* 0 if no connection, 1 we have sent a handshake, 2 if connexion is not confirmed yet
(we have received a handshake but no empty data packet), 3 if the connection is established.
4 if the connection is timed out. */
uint16_t number; /* Lossless_UDP connection number corresponding to this connection. */
} Crypto_Connection;
#define MAX_CRYPTO_CONNECTIONS 256
static Crypto_Connection crypto_connections[MAX_CRYPTO_CONNECTIONS];
#define CONN_NO_CONNECTION 0
#define CONN_HANDSHAKE_SENT 1
#define CONN_NOT_CONFIRMED 2
#define CONN_ESTABLISHED 3
#define CONN_TIMED_OUT 4
#define MAX_INCOMING 64
/* keeps track of the connection numbers for friends request so we can check later if they were sent */
static int incoming_connections[MAX_INCOMING];
/* 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_BOXZEROBYTES + crypto_box_ZEROBYTES;
}
/* 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_ZEROBYTES + crypto_box_BOXZEROBYTES;
}
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);
}
/* increment the given nonce by 1 */
static void increment_nonce(uint8_t *nonce)
{
uint32_t i;
for (i = 0; i < crypto_box_NONCEBYTES; ++i) {
++nonce[i];
if(nonce[i] != 0)
break;
}
}
/* fill the given nonce with random bytes. */
void random_nonce(uint8_t *nonce)
{
uint32_t i, temp;
for (i = 0; i < crypto_box_NONCEBYTES / 4; ++i) {
temp = random_int();
memcpy(nonce + 4 * i, &temp, 4);
}
}
/* 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(int crypt_connection_id, uint8_t *data)
{
if (crypt_connection_id < 0 || crypt_connection_id >= MAX_CRYPTO_CONNECTIONS)
return 0;
if (crypto_connections[crypt_connection_id].status != CONN_ESTABLISHED)
return 0;
uint8_t temp_data[MAX_DATA_SIZE];
int length = read_packet(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(crypto_connections[crypt_connection_id].shared_key,
crypto_connections[crypt_connection_id].recv_nonce,
temp_data + 1, length - 1, data);
if (len != -1) {
increment_nonce(crypto_connections[crypt_connection_id].recv_nonce);
return len;
}
return -1;
}
/* return 0 if data could not be put in packet queue
return 1 if data was put into the queue */
int write_cryptpacket(int crypt_connection_id, uint8_t *data, uint32_t length)
{
if (crypt_connection_id < 0 || crypt_connection_id >= MAX_CRYPTO_CONNECTIONS)
return 0;
if (length - crypto_box_BOXZEROBYTES + crypto_box_ZEROBYTES > MAX_DATA_SIZE - 1)
return 0;
if (crypto_connections[crypt_connection_id].status != CONN_ESTABLISHED)
return 0;
uint8_t temp_data[MAX_DATA_SIZE];
int len = encrypt_data_fast(crypto_connections[crypt_connection_id].shared_key,
crypto_connections[crypt_connection_id].sent_nonce,
data, length, temp_data + 1);
if (len == -1)
return 0;
temp_data[0] = 3;
if (write_packet(crypto_connections[crypt_connection_id].number, temp_data, len + 1) == 0)
return 0;
increment_nonce(crypto_connections[crypt_connection_id].sent_nonce);
return 1;
}
/* create a request to peer with public_key.
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)
returns -1 on failure
returns the length of the created packet on success */
int create_request(uint8_t *packet, uint8_t *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 + ENCRYPTION_PADDING)
return -1;
uint8_t nonce[crypto_box_NONCEBYTES];
uint8_t temp[MAX_DATA_SIZE];
memcpy(temp + 1, data, length);
temp[0] = request_id;
random_nonce(nonce);
int len = encrypt_data(public_key, self_secret_key, nonce, temp, length,
1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + packet);
if (len == -1)
return -1;
packet[0] = 32;
memcpy(packet + 1, public_key, crypto_box_PUBLICKEYBYTES);
memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES, self_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. */
static int handle_request(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 + ENCRYPTION_PADDING &&
length <= MAX_DATA_SIZE + ENCRYPTION_PADDING &&
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;
} else
return -1;
}
static cryptopacket_handler_callback cryptopackethandlers[256] = {0};
void cryptopacket_registerhandler(uint8_t byte, cryptopacket_handler_callback cb)
{
cryptopackethandlers[byte] = cb;
}
static int cryptopacket_handle(IP_Port source, uint8_t * packet, uint32_t length)
{
if (packet[0] == 32) {
if (length <= crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1 + ENCRYPTION_PADDING ||
length > MAX_DATA_SIZE + ENCRYPTION_PADDING)
return 1;
if (memcmp(packet + 1, 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(public_key, data, &number, packet, length);
if (len == -1 || len == 0)
return 1;
if (!cryptopackethandlers[number]) return 1;
cryptopackethandlers[number](source, public_key, data, len - 1);
} else { /* if request is not for us, try routing it. */
if(route_packet(packet + 1, packet, length) == 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(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];
random_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, 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, self_public_key, crypto_box_PUBLICKEYBYTES);
memcpy(temp_data + 1 + crypto_box_PUBLICKEYBYTES, nonce, crypto_box_NONCEBYTES);
return write_packet(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(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, 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(uint8_t *public_key)
{
uint32_t i;
for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i) {
if (crypto_connections[i].status != CONN_NO_CONNECTION)
if (memcmp(public_key, crypto_connections[i].public_key, crypto_box_PUBLICKEYBYTES) == 0)
return i;
}
return -1;
}
/* Start a secure connection with other peer who has public_key and ip_port
returns -1 if failure
returns crypt_connection_id of the initialized connection if everything went well. */
int crypto_connect(uint8_t *public_key, IP_Port ip_port)
{
uint32_t i;
int id = getcryptconnection_id(public_key);
if (id != -1) {
IP_Port c_ip = connection_ip(crypto_connections[id].number);
if(c_ip.ip.i == ip_port.ip.i && c_ip.port == ip_port.port)
return -1;
}
for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i) {
if (crypto_connections[i].status == CONN_NO_CONNECTION) {
int id = new_connection(ip_port);
if (id == -1)
return -1;
crypto_connections[i].number = id;
crypto_connections[i].status = CONN_HANDSHAKE_SENT;
random_nonce(crypto_connections[i].recv_nonce);
memcpy(crypto_connections[i].public_key, public_key, crypto_box_PUBLICKEYBYTES);
crypto_box_keypair(crypto_connections[i].sessionpublic_key, crypto_connections[i].sessionsecret_key);
if (send_cryptohandshake(id, public_key, crypto_connections[i].recv_nonce,
crypto_connections[i].sessionpublic_key) == 1) {
increment_nonce(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(uint8_t *public_key, uint8_t *secret_nonce, uint8_t *session_key)
{
uint32_t i;
for (i = 0; i < MAX_INCOMING; ++i) {
if (incoming_connections[i] != -1) {
if (is_connected(incoming_connections[i]) == 4 || is_connected(incoming_connections[i]) == 0) {
kill_connection(incoming_connections[i]);
incoming_connections[i] = -1;
continue;
}
if (id_packet(incoming_connections[i]) == 2) {
uint8_t temp_data[MAX_DATA_SIZE];
uint16_t len = read_packet(incoming_connections[i], temp_data);
if (handle_cryptohandshake(public_key, secret_nonce, session_key, temp_data, len)) {
int connection_id = incoming_connections[i];
incoming_connections[i] = -1; /* remove this connection from the incoming connection list. */
return connection_id;
}
}
}
}
return -1;
}
/* kill a crypto connection
return 0 if killed successfully
return 1 if there was a problem. */
int crypto_kill(int crypt_connection_id)
{
if (crypt_connection_id < 0 || crypt_connection_id >= MAX_CRYPTO_CONNECTIONS)
return 1;
if (crypto_connections[crypt_connection_id].status != CONN_NO_CONNECTION) {
crypto_connections[crypt_connection_id].status = CONN_NO_CONNECTION;
kill_connection(crypto_connections[crypt_connection_id].number);
memset(&crypto_connections[crypt_connection_id], 0 ,sizeof(Crypto_Connection));
crypto_connections[crypt_connection_id].number = ~0;
return 0;
}
return 1;
}
/* accept an incoming connection using the parameters provided by crypto_inbound
return -1 if not successful
returns the crypt_connection_id if successful */
int accept_crypto_inbound(int connection_id, uint8_t *public_key, uint8_t *secret_nonce, uint8_t *session_key)
{
uint32_t i;
if (connection_id == -1)
return -1;
/*
if(getcryptconnection_id(public_key) != -1)
{
return -1;
}*/
for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i) {
if(crypto_connections[i].status == CONN_NO_CONNECTION) {
crypto_connections[i].number = connection_id;
crypto_connections[i].status = CONN_NOT_CONFIRMED;
random_nonce(crypto_connections[i].recv_nonce);
memcpy(crypto_connections[i].sent_nonce, secret_nonce, crypto_box_NONCEBYTES);
memcpy(crypto_connections[i].peersessionpublic_key, session_key, crypto_box_PUBLICKEYBYTES);
increment_nonce(crypto_connections[i].sent_nonce);
memcpy(crypto_connections[i].public_key, public_key, crypto_box_PUBLICKEYBYTES);
crypto_box_keypair(crypto_connections[i].sessionpublic_key, crypto_connections[i].sessionsecret_key);
if (send_cryptohandshake(connection_id, public_key, crypto_connections[i].recv_nonce,
crypto_connections[i].sessionpublic_key) == 1) {
increment_nonce(crypto_connections[i].recv_nonce);
uint32_t zero = 0;
encrypt_precompute(crypto_connections[i].peersessionpublic_key,
crypto_connections[i].sessionsecret_key,
crypto_connections[i].shared_key);
crypto_connections[i].status = CONN_ESTABLISHED; /* connection status needs to be 3 for write_cryptpacket() to work */
write_cryptpacket(i, ((uint8_t *)&zero), sizeof(zero));
crypto_connections[i].status = 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, 1 we have sent a handshake, 2 if connection is not confirmed yet
(we have received a handshake but no empty data packet), 3 if the connection is established.
4 if the connection is timed out and waiting to be killed */
int is_cryptoconnected(int crypt_connection_id)
{
if (crypt_connection_id >= 0 && crypt_connection_id < MAX_CRYPTO_CONNECTIONS)
return crypto_connections[crypt_connection_id].status;
return CONN_NO_CONNECTION;
}
/* Generate our public and private keys
Only call this function the first time the program starts. */
void new_keys(void)
{
crypto_box_keypair(self_public_key,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(uint8_t *keys)
{
memcpy(keys, self_public_key, crypto_box_PUBLICKEYBYTES);
memcpy(keys + crypto_box_PUBLICKEYBYTES, 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(uint8_t *keys)
{
memcpy(self_public_key, keys, crypto_box_PUBLICKEYBYTES);
memcpy(self_secret_key, keys + crypto_box_PUBLICKEYBYTES, crypto_box_SECRETKEYBYTES);
}
/* TODO: optimize this
adds an incoming connection to the incoming_connection list.
returns 0 if successful
returns 1 if failure */
static int new_incoming(int id)
{
uint32_t i;
for (i = 0; i < MAX_INCOMING; ++i) {
if (incoming_connections[i] == -1) {
incoming_connections[i] = id;
return 0;
}
}
return 1;
}
/* TODO: optimize this
handle all new incoming connections. */
static void handle_incomings(void)
{
int income;
while (1) {
income = incoming_connection();
if(income == -1 || new_incoming(income) )
break;
}
}
/* handle received packets for not yet established crypto connections. */
static void receive_crypto(void)
{
uint32_t i;
for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i) {
if (crypto_connections[i].status == 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(crypto_connections[i].number) == 1)
/* if the packet is a friend request drop it (because we are already friends) */
len = read_packet(crypto_connections[i].number, temp_data);
if (id_packet(crypto_connections[i].number) == 2) { /* handle handshake packet. */
len = read_packet(crypto_connections[i].number, temp_data);
if (handle_cryptohandshake(public_key, secret_nonce, session_key, temp_data, len)) {
if (memcmp(public_key, crypto_connections[i].public_key, crypto_box_PUBLICKEYBYTES) == 0) {
memcpy(crypto_connections[i].sent_nonce, secret_nonce, crypto_box_NONCEBYTES);
memcpy(crypto_connections[i].peersessionpublic_key, session_key, crypto_box_PUBLICKEYBYTES);
increment_nonce(crypto_connections[i].sent_nonce);
uint32_t zero = 0;
encrypt_precompute(crypto_connections[i].peersessionpublic_key,
crypto_connections[i].sessionsecret_key,
crypto_connections[i].shared_key);
crypto_connections[i].status = CONN_ESTABLISHED; /* connection status needs to be 3 for write_cryptpacket() to work */
write_cryptpacket(i, ((uint8_t *)&zero), sizeof(zero));
crypto_connections[i].status = CONN_NOT_CONFIRMED; /* set it to its proper value right after. */
}
}
} else if (id_packet(crypto_connections[i].number) != -1) // This should not happen kill the connection if it does
crypto_kill(crypto_connections[i].number);
}
if (crypto_connections[i].status == CONN_NOT_CONFIRMED) {
if (id_packet(crypto_connections[i].number) == 3) {
uint8_t temp_data[MAX_DATA_SIZE];
uint8_t data[MAX_DATA_SIZE];
int length = read_packet(crypto_connections[i].number, temp_data);
int len = decrypt_data(crypto_connections[i].peersessionpublic_key,
crypto_connections[i].sessionsecret_key,
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(crypto_connections[i].recv_nonce);
encrypt_precompute(crypto_connections[i].peersessionpublic_key,
crypto_connections[i].sessionsecret_key,
crypto_connections[i].shared_key);
crypto_connections[i].status = CONN_ESTABLISHED;
/* connection is accepted so we disable the auto kill by setting it to about 1 month from now. */
kill_connection_in(crypto_connections[i].number, 3000000);
} else
crypto_kill(crypto_connections[i].number); // This should not happen kill the connection if it does
} else if(id_packet(crypto_connections[i].number) != -1)
/* This should not happen
kill the connection if it does */
crypto_kill(crypto_connections[i].number);
}
}
}
/* run this to (re)initialize net_crypto
sets all the global connection variables to their default values. */
void initNetCrypto(void)
{
memset(crypto_connections, 0 ,sizeof(crypto_connections));
memset(incoming_connections, -1 ,sizeof(incoming_connections));
networking_registerhandler(32, &cryptopacket_handle);
uint32_t i;
for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i)
crypto_connections[i].number = ~0;
}
static void killTimedout(void)
{
uint32_t i;
for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i) {
if (crypto_connections[i].status != CONN_NO_CONNECTION && is_connected(crypto_connections[i].number) == 4)
crypto_connections[i].status = CONN_TIMED_OUT;
else if (is_connected(crypto_connections[i].number) == 4) {
kill_connection(crypto_connections[i].number);
crypto_connections[i].number = ~0;
}
}
}
/* main loop */
void doNetCrypto(void)
{
/* TODO:check if friend requests were sent correctly
handle new incoming connections
handle friend requests */
handle_incomings();
receive_crypto();
killTimedout();
}
Reference in New Issue View Git Blame Copy Permalink