mirror of
https://github.com/irungentoo/toxcore.git
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650 lines
28 KiB
C
650 lines
28 KiB
C
/* net_crypto.c
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*
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* Functions for the core network crypto.
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* See also: http://wiki.tox.im/index.php/DHT
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*
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* NOTE: This code has to be perfect. We don't mess around with encryption.
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*
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* Copyright (C) 2013 Tox project All Rights Reserved.
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*
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* This file is part of Tox.
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*
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* Tox is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Tox is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Tox. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "net_crypto.h"
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/* Our public and secret keys. */
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uint8_t self_public_key[crypto_box_PUBLICKEYBYTES];
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uint8_t self_secret_key[crypto_box_SECRETKEYBYTES];
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typedef struct {
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uint8_t public_key[crypto_box_PUBLICKEYBYTES]; /* the real public key of the peer. */
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uint8_t recv_nonce[crypto_box_NONCEBYTES]; /* nonce of received packets */
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uint8_t sent_nonce[crypto_box_NONCEBYTES]; /* nonce of sent packets. */
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uint8_t sessionpublic_key[crypto_box_PUBLICKEYBYTES]; /* our public key for this session. */
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uint8_t sessionsecret_key[crypto_box_SECRETKEYBYTES]; /* our private key for this session. */
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uint8_t peersessionpublic_key[crypto_box_PUBLICKEYBYTES]; /* The public key of the peer. */
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uint8_t shared_key[crypto_box_BEFORENMBYTES]; /* the precomputed shared key from encrypt_precompute */
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uint8_t status; /* 0 if no connection, 1 we have sent a handshake, 2 if connexion is not confirmed yet
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(we have received a handshake but no empty data packet), 3 if the connection is established.
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4 if the connection is timed out. */
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uint16_t number; /* Lossless_UDP connection number corresponding to this connection. */
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} Crypto_Connection;
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#define MAX_CRYPTO_CONNECTIONS 256
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static Crypto_Connection crypto_connections[MAX_CRYPTO_CONNECTIONS];
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#define CONN_NO_CONNECTION 0
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#define CONN_HANDSHAKE_SENT 1
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#define CONN_NOT_CONFIRMED 2
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#define CONN_ESTABLISHED 3
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#define CONN_TIMED_OUT 4
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#define MAX_INCOMING 64
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/* keeps track of the connection numbers for friends request so we can check later if they were sent */
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static int incoming_connections[MAX_INCOMING];
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/* Use this instead of memcmp; not vulnerable to timing attacks. */
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uint8_t crypto_iszero(uint8_t *mem, uint32_t length)
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{
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uint8_t check = 0;
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uint32_t i;
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for (i = 0; i < length; ++i) {
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check |= mem[i];
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}
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return check; // We return zero if mem is made out of zeroes.
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}
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/* encrypts plain of length length to encrypted of length + 16 using the
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public key(32 bytes) of the receiver and the secret key of the sender and a 24 byte nonce
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return -1 if there was a problem.
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return length of encrypted data if everything was fine. */
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int encrypt_data(uint8_t *public_key, uint8_t *secret_key, uint8_t *nonce,
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uint8_t *plain, uint32_t length, uint8_t *encrypted)
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{
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if (length + crypto_box_MACBYTES > MAX_DATA_SIZE || length == 0)
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return -1;
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uint8_t temp_plain[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES] = {0};
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uint8_t temp_encrypted[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES];
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memcpy(temp_plain + crypto_box_ZEROBYTES, plain, length); /* pad the message with 32 0 bytes. */
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crypto_box(temp_encrypted, temp_plain, length + crypto_box_ZEROBYTES, nonce, public_key, secret_key);
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/* if encryption is successful the first crypto_box_BOXZEROBYTES of the message will be zero
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apparently memcmp should not be used so we do this instead:*/
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if(crypto_iszero(temp_encrypted, crypto_box_BOXZEROBYTES) != 0)
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return -1;
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/* unpad the encrypted message */
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memcpy(encrypted, temp_encrypted + crypto_box_BOXZEROBYTES, length + crypto_box_MACBYTES);
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return length - crypto_box_BOXZEROBYTES + crypto_box_ZEROBYTES;
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}
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/* Precomputes the shared key from their public_key and our secret_key.
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This way we can avoid an expensive elliptic curve scalar multiply for each
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encrypt/decrypt operation.
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enc_key has to be crypto_box_BEFORENMBYTES bytes long. */
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void encrypt_precompute(uint8_t *public_key, uint8_t *secret_key, uint8_t *enc_key)
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{
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crypto_box_beforenm(enc_key, public_key, secret_key);
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}
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/* Fast encrypt. Depends on enc_key from encrypt_precompute. */
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int encrypt_data_fast(uint8_t *enc_key, uint8_t *nonce,
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uint8_t *plain, uint32_t length, uint8_t *encrypted)
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{
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if (length + crypto_box_MACBYTES > MAX_DATA_SIZE || length == 0)
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return -1;
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uint8_t temp_plain[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES] = {0};
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uint8_t temp_encrypted[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES];
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memcpy(temp_plain + crypto_box_ZEROBYTES, plain, length); /* pad the message with 32 0 bytes. */
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crypto_box_afternm(temp_encrypted, temp_plain, length + crypto_box_ZEROBYTES, nonce, enc_key);
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if(crypto_iszero(temp_encrypted, crypto_box_BOXZEROBYTES) != 0)
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return -1;
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/* unpad the encrypted message */
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memcpy(encrypted, temp_encrypted + crypto_box_BOXZEROBYTES, length + crypto_box_MACBYTES);
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return length - crypto_box_BOXZEROBYTES + crypto_box_ZEROBYTES;
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}
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/* decrypts encrypted of length length to plain of length length - 16 using the
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public key(32 bytes) of the sender, the secret key of the receiver and a 24 byte nonce
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return -1 if there was a problem(decryption failed)
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return length of plain data if everything was fine. */
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int decrypt_data(uint8_t *public_key, uint8_t *secret_key, uint8_t *nonce,
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uint8_t *encrypted, uint32_t length, uint8_t *plain)
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{
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if (length > MAX_DATA_SIZE || length <= crypto_box_BOXZEROBYTES)
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return -1;
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uint8_t temp_plain[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES];
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uint8_t temp_encrypted[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES] = {0};
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memcpy(temp_encrypted + crypto_box_BOXZEROBYTES, encrypted, length); /* pad the message with 16 0 bytes. */
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if (crypto_box_open(temp_plain, temp_encrypted, length + crypto_box_BOXZEROBYTES,
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nonce, public_key, secret_key) == -1)
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return -1;
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/* if decryption is successful the first crypto_box_ZEROBYTES of the message will be zero
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apparently memcmp should not be used so we do this instead:*/
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if(crypto_iszero(temp_plain, crypto_box_ZEROBYTES) != 0)
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return -1;
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/* unpad the plain message */
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memcpy(plain, temp_plain + crypto_box_ZEROBYTES, length - crypto_box_MACBYTES);
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return length - crypto_box_ZEROBYTES + crypto_box_BOXZEROBYTES;
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}
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/* Fast decrypt. Depends on enc_ley from encrypt_precompute. */
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int decrypt_data_fast(uint8_t *enc_key, uint8_t *nonce,
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uint8_t *encrypted, uint32_t length, uint8_t *plain)
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{
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if (length > MAX_DATA_SIZE || length <= crypto_box_BOXZEROBYTES)
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return -1;
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uint8_t temp_plain[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES];
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uint8_t temp_encrypted[MAX_DATA_SIZE + crypto_box_BOXZEROBYTES] = {0};
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memcpy(temp_encrypted + crypto_box_BOXZEROBYTES, encrypted, length); /* pad the message with 16 0 bytes. */
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if (crypto_box_open_afternm(temp_plain, temp_encrypted, length + crypto_box_BOXZEROBYTES,
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nonce, enc_key) == -1)
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return -1;
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/* if decryption is successful the first crypto_box_ZEROBYTES of the message will be zero
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apparently memcmp should not be used so we do this instead:*/
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if(crypto_iszero(temp_plain, crypto_box_ZEROBYTES) != 0)
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return -1;
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/* unpad the plain message */
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memcpy(plain, temp_plain + crypto_box_ZEROBYTES, length - crypto_box_MACBYTES);
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return length - crypto_box_ZEROBYTES + crypto_box_BOXZEROBYTES;
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}
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/* increment the given nonce by 1 */
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static void increment_nonce(uint8_t *nonce)
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{
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uint32_t i;
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for (i = 0; i < crypto_box_NONCEBYTES; ++i) {
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++nonce[i];
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if(nonce[i] != 0)
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break;
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}
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}
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/* fill the given nonce with random bytes. */
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void random_nonce(uint8_t *nonce)
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{
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uint32_t i, temp;
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for (i = 0; i < crypto_box_NONCEBYTES / 4; ++i) {
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temp = random_int();
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memcpy(nonce + 4 * i, &temp, 4);
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}
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}
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/* return 0 if there is no received data in the buffer
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return -1 if the packet was discarded.
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return length of received data if successful */
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int read_cryptpacket(int crypt_connection_id, uint8_t *data)
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{
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if (crypt_connection_id < 0 || crypt_connection_id >= MAX_CRYPTO_CONNECTIONS)
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return 0;
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if (crypto_connections[crypt_connection_id].status != CONN_ESTABLISHED)
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return 0;
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uint8_t temp_data[MAX_DATA_SIZE];
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int length = read_packet(crypto_connections[crypt_connection_id].number, temp_data);
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if (length == 0)
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return 0;
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if (temp_data[0] != 3)
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return -1;
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int len = decrypt_data_fast(crypto_connections[crypt_connection_id].shared_key,
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crypto_connections[crypt_connection_id].recv_nonce,
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temp_data + 1, length - 1, data);
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if (len != -1) {
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increment_nonce(crypto_connections[crypt_connection_id].recv_nonce);
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return len;
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}
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return -1;
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}
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/* return 0 if data could not be put in packet queue
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return 1 if data was put into the queue */
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int write_cryptpacket(int crypt_connection_id, uint8_t *data, uint32_t length)
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{
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if (crypt_connection_id < 0 || crypt_connection_id >= MAX_CRYPTO_CONNECTIONS)
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return 0;
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if (length - crypto_box_BOXZEROBYTES + crypto_box_ZEROBYTES > MAX_DATA_SIZE - 1)
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return 0;
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if (crypto_connections[crypt_connection_id].status != CONN_ESTABLISHED)
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return 0;
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uint8_t temp_data[MAX_DATA_SIZE];
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int len = encrypt_data_fast(crypto_connections[crypt_connection_id].shared_key,
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crypto_connections[crypt_connection_id].sent_nonce,
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data, length, temp_data + 1);
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if (len == -1)
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return 0;
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temp_data[0] = 3;
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if (write_packet(crypto_connections[crypt_connection_id].number, temp_data, len + 1) == 0)
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return 0;
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increment_nonce(crypto_connections[crypt_connection_id].sent_nonce);
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return 1;
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}
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/* create a request to peer with public_key.
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packet must be an array of MAX_DATA_SIZE big.
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Data represents the data we send with the request with length being the length of the data.
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request_id is the id of the request (32 = friend request, 254 = ping request)
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returns -1 on failure
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returns the length of the created packet on success */
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int create_request(uint8_t *packet, uint8_t *public_key, uint8_t *data, uint32_t length, uint8_t request_id)
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{
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if (MAX_DATA_SIZE < length + 1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + ENCRYPTION_PADDING)
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return -1;
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uint8_t nonce[crypto_box_NONCEBYTES];
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random_nonce(nonce);
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int len = encrypt_data(public_key, self_secret_key, nonce, data, length,
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1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + packet);
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if (len == -1)
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return -1;
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packet[0] = request_id;
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memcpy(packet + 1, public_key, crypto_box_PUBLICKEYBYTES);
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memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES, self_public_key, crypto_box_PUBLICKEYBYTES);
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memcpy(packet + 1 + crypto_box_PUBLICKEYBYTES * 2, nonce, crypto_box_NONCEBYTES);
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return len + 1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES;
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}
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/* puts the senders public key in the request in public_key, the data from the request
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in data if a friend or ping request was sent to us and returns the length of the data.
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packet is the request packet and length is its length
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return -1 if not valid request. */
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int handle_request(uint8_t *public_key, uint8_t *data, uint8_t *packet, uint16_t length)
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{
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if (length > crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1 + ENCRYPTION_PADDING &&
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length <= MAX_DATA_SIZE + ENCRYPTION_PADDING &&
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memcmp(packet + 1, self_public_key, crypto_box_PUBLICKEYBYTES) == 0) {
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memcpy(public_key, packet + 1 + crypto_box_PUBLICKEYBYTES, crypto_box_PUBLICKEYBYTES);
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uint8_t nonce[crypto_box_NONCEBYTES];
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memcpy(nonce, packet + 1 + crypto_box_PUBLICKEYBYTES * 2, crypto_box_NONCEBYTES);
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int len1 = decrypt_data(public_key, self_secret_key, nonce, packet + 1 + crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES,
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length - (crypto_box_PUBLICKEYBYTES * 2 + crypto_box_NONCEBYTES + 1), data);
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if(len1 == -1)
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return -1;
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return len1;
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} else
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return -1;
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}
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/* Send a crypto handshake packet containing an encrypted secret nonce and session public key
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to peer with connection_id and public_key
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the packet is encrypted with a random nonce which is sent in plain text with the packet */
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static int send_cryptohandshake(int connection_id, uint8_t *public_key, uint8_t *secret_nonce, uint8_t *session_key)
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{
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uint8_t temp_data[MAX_DATA_SIZE];
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uint8_t temp[crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES];
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uint8_t nonce[crypto_box_NONCEBYTES];
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random_nonce(nonce);
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memcpy(temp, secret_nonce, crypto_box_NONCEBYTES);
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memcpy(temp + crypto_box_NONCEBYTES, session_key, crypto_box_PUBLICKEYBYTES);
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int len = encrypt_data(public_key, self_secret_key, nonce, temp, crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES,
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1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES + temp_data);
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if (len == -1)
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return 0;
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temp_data[0] = 2;
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memcpy(temp_data + 1, self_public_key, crypto_box_PUBLICKEYBYTES);
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memcpy(temp_data + 1 + crypto_box_PUBLICKEYBYTES, nonce, crypto_box_NONCEBYTES);
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return write_packet(connection_id, temp_data, len + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES);
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}
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/* Extract secret nonce, session public key and public_key from a packet(data) with length length
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return 1 if successful
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return 0 if failure */
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static int handle_cryptohandshake(uint8_t *public_key, uint8_t *secret_nonce,
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uint8_t *session_key, uint8_t *data, uint16_t length)
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{
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int pad = (- crypto_box_BOXZEROBYTES + crypto_box_ZEROBYTES);
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if (length != 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES
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+ crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + pad) {
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return 0;
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}
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if (data[0] != 2)
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return 0;
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uint8_t temp[crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES];
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memcpy(public_key, data + 1, crypto_box_PUBLICKEYBYTES);
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int len = decrypt_data(public_key, self_secret_key, data + 1 + crypto_box_PUBLICKEYBYTES,
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data + 1 + crypto_box_PUBLICKEYBYTES + crypto_box_NONCEBYTES,
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crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES + pad, temp);
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if (len != crypto_box_NONCEBYTES + crypto_box_PUBLICKEYBYTES)
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return 0;
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memcpy(secret_nonce, temp, crypto_box_NONCEBYTES);
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memcpy(session_key, temp + crypto_box_NONCEBYTES, crypto_box_PUBLICKEYBYTES);
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return 1;
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}
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/* get crypto connection id from public key of peer
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return -1 if there are no connections like we are looking for
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return id if it found it */
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static int getcryptconnection_id(uint8_t *public_key)
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{
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uint32_t i;
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for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i) {
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if (crypto_connections[i].status != CONN_NO_CONNECTION)
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if (memcmp(public_key, crypto_connections[i].public_key, crypto_box_PUBLICKEYBYTES) == 0)
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return i;
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}
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return -1;
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}
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/* Start a secure connection with other peer who has public_key and ip_port
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returns -1 if failure
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returns crypt_connection_id of the initialized connection if everything went well. */
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int crypto_connect(uint8_t *public_key, IP_Port ip_port)
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{
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uint32_t i;
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int id = getcryptconnection_id(public_key);
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if (id != -1) {
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IP_Port c_ip = connection_ip(crypto_connections[id].number);
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if(c_ip.ip.i == ip_port.ip.i && c_ip.port == ip_port.port)
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return -1;
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}
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for (i = 0; i < MAX_CRYPTO_CONNECTIONS; ++i) {
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if (crypto_connections[i].status == CONN_NO_CONNECTION) {
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int id = new_connection(ip_port);
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if (id == -1)
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return -1;
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crypto_connections[i].number = id;
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crypto_connections[i].status = CONN_HANDSHAKE_SENT;
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random_nonce(crypto_connections[i].recv_nonce);
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memcpy(crypto_connections[i].public_key, public_key, crypto_box_PUBLICKEYBYTES);
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crypto_box_keypair(crypto_connections[i].sessionpublic_key, crypto_connections[i].sessionsecret_key);
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if (send_cryptohandshake(id, public_key, crypto_connections[i].recv_nonce,
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crypto_connections[i].sessionpublic_key) == 1) {
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increment_nonce(crypto_connections[i].recv_nonce);
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return i;
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}
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return -1; /* this should never happen. */
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}
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}
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return -1;
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}
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/* handle an incoming connection
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return -1 if no crypto inbound connection
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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));
|
|
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();
|
|
}
|