5 Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
7 Copyright (C) 1997 - 2001 Pekka Riikonen
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
21 /* This file includes channel message sending and receiving routines,
22 channel key receiving and setting, and channel private key handling
25 #include "clientlibincludes.h"
26 #include "client_internal.h"
28 /* Sends packet to the `channel'. Packet to channel is always encrypted
29 differently from "normal" packets. SILC header of the packet is
30 encrypted with the next receiver's key and the rest of the packet is
31 encrypted with the channel specific key. Padding and HMAC is computed
32 with the next receiver's key. The `data' is the channel message. If
33 the `force_send' is TRUE then the packet is sent immediately. */
35 void silc_client_send_channel_message(SilcClient client,
36 SilcClientConnection conn,
37 SilcChannelEntry channel,
38 SilcChannelPrivateKey key,
39 SilcMessageFlags flags,
45 SilcSocketConnection sock = conn->sock;
47 SilcPacketContext packetdata;
50 unsigned char *id_string;
54 SILC_LOG_DEBUG(("Sending packet to channel"));
56 /* Take the key to be used */
57 if (channel->mode & SILC_CHANNEL_MODE_PRIVKEY) {
59 /* Use key application specified */
62 } else if (channel->curr_key) {
63 /* Use current private key */
64 cipher = channel->curr_key->cipher;
65 hmac = channel->curr_key->hmac;
66 } else if (!channel->curr_key && channel->private_keys) {
67 /* Use just some private key since we don't know what to use
68 and private keys are set. */
69 silc_dlist_start(channel->private_keys);
70 key = silc_dlist_get(channel->private_keys);
74 /* Use this key as current private key */
75 channel->curr_key = key;
77 /* Use normal channel key generated by the server */
78 cipher = channel->channel_key;
82 /* Use normal channel key generated by the server */
83 cipher = channel->channel_key;
90 block_len = silc_cipher_get_block_len(cipher);
93 iv_len = silc_cipher_get_block_len(cipher);
94 if (channel->iv[0] == '\0')
95 for (i = 0; i < iv_len; i++) channel->iv[i] =
96 silc_rng_get_byte(client->rng);
98 silc_hash_make(client->md5hash, channel->iv, iv_len, channel->iv);
100 /* Encode the channel payload. This also encrypts the message payload. */
101 payload = silc_channel_message_payload_encode(flags, data_len, data, iv_len,
102 channel->iv, cipher, hmac);
104 /* Get data used in packet header encryption, keys and stuff. */
105 cipher = conn->send_key;
106 hmac = conn->hmac_send;
107 id_string = silc_id_id2str(channel->id, SILC_ID_CHANNEL);
109 /* Set the packet context pointers. The destination ID is always
110 the Channel ID of the channel. Server and router will handle the
111 distribution of the packet. */
112 packetdata.flags = 0;
113 packetdata.type = SILC_PACKET_CHANNEL_MESSAGE;
114 packetdata.src_id = conn->local_id_data;
115 packetdata.src_id_len = silc_id_get_len(conn->local_id, SILC_ID_CLIENT);
116 packetdata.src_id_type = SILC_ID_CLIENT;
117 packetdata.dst_id = id_string;
118 packetdata.dst_id_len = silc_id_get_len(channel->id, SILC_ID_CHANNEL);
119 packetdata.dst_id_type = SILC_ID_CHANNEL;
120 packetdata.truelen = payload->len + SILC_PACKET_HEADER_LEN +
121 packetdata.src_id_len + packetdata.dst_id_len;
122 packetdata.padlen = SILC_PACKET_PADLEN((SILC_PACKET_HEADER_LEN +
123 packetdata.src_id_len +
124 packetdata.dst_id_len), block_len);
126 /* Prepare outgoing data buffer for packet sending */
127 silc_packet_send_prepare(sock,
128 SILC_PACKET_HEADER_LEN +
129 packetdata.src_id_len +
130 packetdata.dst_id_len,
134 packetdata.buffer = sock->outbuf;
136 /* Put the channel message payload to the outgoing data buffer */
137 silc_buffer_put(sock->outbuf, payload->data, payload->len);
139 /* Create the outgoing packet */
140 silc_packet_assemble(&packetdata, cipher);
142 /* Encrypt the header and padding of the packet. This is encrypted
143 with normal session key shared with our server. */
144 silc_packet_encrypt(cipher, hmac, conn->psn_send++,
145 sock->outbuf, SILC_PACKET_HEADER_LEN +
146 packetdata.src_id_len + packetdata.dst_id_len +
149 SILC_LOG_HEXDUMP(("Packet to channel, len %d", sock->outbuf->len),
150 sock->outbuf->data, sock->outbuf->len);
152 /* Now actually send the packet */
153 silc_client_packet_send_real(client, sock, force_send);
154 silc_buffer_free(payload);
155 silc_free(id_string);
159 SilcChannelMessagePayload payload;
160 SilcChannelID *channel_id;
161 } *SilcChannelClientResolve;
163 static void silc_client_channel_message_cb(SilcClient client,
164 SilcClientConnection conn,
165 SilcClientEntry *clients,
166 uint32 clients_count,
169 SilcChannelClientResolve res = (SilcChannelClientResolve)context;
171 if (clients_count == 1) {
172 SilcIDCacheEntry id_cache = NULL;
173 SilcChannelEntry channel;
174 unsigned char *message;
176 if (!silc_idcache_find_by_id_one(conn->channel_cache, res->channel_id,
180 channel = (SilcChannelEntry)id_cache->context;
181 message = silc_channel_message_get_data(res->payload, NULL);
183 /* Pass the message to application */
184 client->ops->channel_message(client, conn, clients[0], channel,
185 silc_channel_message_get_flags(res->payload),
190 silc_channel_message_payload_free(res->payload);
191 silc_free(res->channel_id);
195 /* Process received message to a channel (or from a channel, really). This
196 decrypts the channel message with channel specific key and parses the
197 channel payload. Finally it displays the message on the screen. */
199 void silc_client_channel_message(SilcClient client,
200 SilcSocketConnection sock,
201 SilcPacketContext *packet)
203 SilcClientConnection conn = (SilcClientConnection)sock->user_data;
204 SilcBuffer buffer = packet->buffer;
205 SilcChannelMessagePayload payload = NULL;
206 SilcChannelID *id = NULL;
207 SilcChannelEntry channel;
209 SilcIDCacheEntry id_cache = NULL;
210 SilcClientID *client_id = NULL;
212 unsigned char *message;
214 SILC_LOG_DEBUG(("Start"));
217 if (packet->dst_id_type != SILC_ID_CHANNEL)
220 client_id = silc_id_str2id(packet->src_id, packet->src_id_len,
224 id = silc_id_str2id(packet->dst_id, packet->dst_id_len, SILC_ID_CHANNEL);
228 /* Find the channel entry from channels on this connection */
229 if (!silc_idcache_find_by_id_one(conn->channel_cache, (void *)id, &id_cache))
232 channel = (SilcChannelEntry)id_cache->context;
234 /* If there is no channel private key then just decrypt the message
235 with the channel key. If private keys are set then just go through
236 all private keys and check what decrypts correctly. */
237 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY)) {
238 /* Parse the channel message payload. This also decrypts the payload */
239 payload = silc_channel_message_payload_parse(buffer, channel->channel_key,
242 /* If decryption failed and we have just performed channel key rekey
243 we will use the old key in decryption. If that fails too then we
244 cannot do more and will drop the packet. */
246 if (!channel->old_channel_key)
249 payload = silc_channel_message_payload_parse(buffer,
250 channel->old_channel_key,
255 } else if (channel->private_keys) {
256 SilcChannelPrivateKey entry;
258 silc_dlist_start(channel->private_keys);
259 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
260 /* Parse the channel message payload. This also decrypts the payload */
261 payload = silc_channel_message_payload_parse(buffer, entry->cipher,
266 if (entry == SILC_LIST_END)
272 /* Find client entry */
273 silc_list_start(channel->clients);
274 while ((chu = silc_list_get(channel->clients)) != SILC_LIST_END) {
275 if (SILC_ID_CLIENT_COMPARE(chu->client->id, client_id) &&
276 chu->client->nickname) {
283 /* Resolve the client info */
284 SilcChannelClientResolve res = silc_calloc(1, sizeof(*res));
285 res->payload = payload;
286 res->channel_id = id;
287 silc_client_get_client_by_id_resolve(client, conn, client_id,
288 silc_client_channel_message_cb,
295 message = silc_channel_message_get_data(payload, NULL);
297 /* Pass the message to application */
298 client->ops->channel_message(client, conn, chu->client, channel,
299 silc_channel_message_get_flags(payload),
306 silc_free(client_id);
308 silc_channel_message_payload_free(payload);
311 /* Timeout callback that is called after a short period of time after the
312 new channel key has been created. This removes the old channel key all
315 SILC_TASK_CALLBACK(silc_client_save_channel_key_rekey)
317 SilcChannelEntry channel = (SilcChannelEntry)context;
319 if (channel->old_channel_key)
320 silc_cipher_free(channel->old_channel_key);
321 if (channel->old_hmac)
322 silc_hmac_free(channel->old_hmac);
323 channel->old_channel_key = NULL;
324 channel->old_hmac = NULL;
325 channel->rekey_task = NULL;
328 /* Saves channel key from encoded `key_payload'. This is used when we
329 receive Channel Key Payload and when we are processing JOIN command
332 void silc_client_save_channel_key(SilcClientConnection conn,
333 SilcBuffer key_payload,
334 SilcChannelEntry channel)
336 unsigned char *id_string, *key, *cipher, *hmac, hash[32];
339 SilcIDCacheEntry id_cache = NULL;
340 SilcChannelKeyPayload payload;
342 payload = silc_channel_key_payload_parse(key_payload);
346 id_string = silc_channel_key_get_id(payload, &tmp_len);
348 silc_channel_key_payload_free(payload);
352 id = silc_id_str2id(id_string, tmp_len, SILC_ID_CHANNEL);
354 silc_channel_key_payload_free(payload);
360 if (!silc_idcache_find_by_id_one(conn->channel_cache,
361 (void *)id, &id_cache))
364 /* Get channel entry */
365 channel = (SilcChannelEntry)id_cache->context;
368 hmac = (channel->hmac ? (char *)silc_hmac_get_name(channel->hmac) :
371 /* Save the old key for a short period of time so that we can decrypt
372 channel message even after the rekey if some client would be sending
373 messages with the old key after the rekey. */
374 if (channel->old_channel_key)
375 silc_cipher_free(channel->old_channel_key);
376 if (channel->old_hmac)
377 silc_hmac_free(channel->old_hmac);
378 if (channel->rekey_task)
379 silc_schedule_task_del(conn->client->schedule, channel->rekey_task);
380 channel->old_channel_key = channel->channel_key;
381 channel->old_hmac = channel->hmac;
382 channel->rekey_task =
383 silc_schedule_task_add(conn->client->schedule, 0,
384 silc_client_save_channel_key_rekey, channel,
385 10, 0, SILC_TASK_TIMEOUT, SILC_TASK_PRI_NORMAL);
387 /* Free the old channel key data */
388 silc_free(channel->key);
391 key = silc_channel_key_get_key(payload, &tmp_len);
392 cipher = silc_channel_key_get_cipher(payload, NULL);
393 channel->key_len = tmp_len * 8;
394 channel->key = silc_calloc(tmp_len, sizeof(*channel->key));
395 memcpy(channel->key, key, tmp_len);
397 if (!silc_cipher_alloc(cipher, &channel->channel_key)) {
398 conn->client->ops->say(conn->client, conn, SILC_CLIENT_MESSAGE_AUDIT,
399 "Cannot talk to channel: unsupported cipher %s",
404 /* Set the cipher key */
405 silc_cipher_set_key(channel->channel_key, key, channel->key_len);
407 /* Generate HMAC key from the channel key data and set it */
408 silc_hmac_alloc(hmac, NULL, &channel->hmac);
409 silc_hash_make(silc_hmac_get_hash(channel->hmac), key, tmp_len, hash);
410 silc_hmac_set_key(channel->hmac, hash,
411 silc_hash_len(silc_hmac_get_hash(channel->hmac)));
412 memset(hash, 0, sizeof(hash));
416 silc_channel_key_payload_free(payload);
419 /* Processes received key for channel. The received key will be used
420 to protect the traffic on the channel for now on. Client must receive
421 the key to the channel before talking on the channel is possible.
422 This is the key that server has generated, this is not the channel
423 private key, it is entirely local setting. */
425 void silc_client_receive_channel_key(SilcClient client,
426 SilcSocketConnection sock,
429 SILC_LOG_DEBUG(("Received key for channel"));
432 silc_client_save_channel_key(sock->user_data, packet, NULL);
435 /* Adds private key for channel. This may be set only if the channel's mode
436 mask includes the SILC_CHANNEL_MODE_PRIVKEY. This returns FALSE if the
437 mode is not set. When channel has private key then the messages are
438 encrypted using that key. All clients on the channel must also know the
439 key in order to decrypt the messages. However, it is possible to have
440 several private keys per one channel. In this case only some of the
441 clients on the channel may know the one key and only some the other key.
443 If `cipher' and/or `hmac' is NULL then default values will be used
444 (aes-256-cbc for cipher and hmac-sha1-96 for hmac).
446 The private key for channel is optional. If it is not set then the
447 channel messages are encrypted using the channel key generated by the
448 server. However, setting the private key (or keys) for the channel
449 significantly adds security. If more than one key is set the library
450 will automatically try all keys at the message decryption phase. Note:
451 setting many keys slows down the decryption phase as all keys has to
452 be tried in order to find the correct decryption key. However, setting
453 a few keys does not have big impact to the decryption performace.
455 NOTE: that this is entirely local setting. The key set using this function
456 is not sent to the network at any phase.
458 NOTE: If the key material was originated by the SKE protocol (using
459 silc_client_send_key_agreement) then the `key' MUST be the
460 key->send_enc_key as this is dictated by the SILC protocol. However,
461 currently it is not expected that the SKE key material would be used
462 as channel private key. However, this API allows it. */
464 int silc_client_add_channel_private_key(SilcClient client,
465 SilcClientConnection conn,
466 SilcChannelEntry channel,
472 SilcChannelPrivateKey entry;
473 unsigned char hash[32];
474 SilcSKEKeyMaterial *keymat;
476 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY))
480 cipher = SILC_DEFAULT_CIPHER;
482 hmac = SILC_DEFAULT_HMAC;
484 if (!silc_cipher_is_supported(cipher))
487 if (!silc_hmac_is_supported(hmac))
490 /* Produce the key material */
491 keymat = silc_calloc(1, sizeof(*keymat));
492 if (silc_ske_process_key_material_data(key, key_len, 16, 256, 16,
493 client->md5hash, keymat)
494 != SILC_SKE_STATUS_OK)
497 /* Remove the current key, if it exists. */
498 if (channel->channel_key) {
499 silc_cipher_free(channel->channel_key);
500 memset(channel->key, 0, channel->key_len / 8);
501 silc_free(channel->key);
502 channel->channel_key = NULL;
504 channel->key_len = 0;
507 silc_hmac_free(channel->hmac);
508 channel->hmac = NULL;
511 if (!channel->private_keys)
512 channel->private_keys = silc_dlist_init();
515 entry = silc_calloc(1, sizeof(*entry));
516 entry->key = silc_calloc(keymat->enc_key_len / 8, sizeof(*entry->key));
517 memcpy(entry->key, keymat->send_enc_key, keymat->enc_key_len / 8);
518 entry->key_len = keymat->enc_key_len / 8;
520 /* Allocate the cipher and set the key*/
521 silc_cipher_alloc(cipher, &entry->cipher);
522 silc_cipher_set_key(entry->cipher, entry->key, keymat->enc_key_len);
524 /* Generate HMAC key from the channel key data and set it */
525 silc_hmac_alloc(hmac, NULL, &entry->hmac);
526 silc_hash_make(silc_hmac_get_hash(entry->hmac), entry->key,
527 entry->key_len, hash);
528 silc_hmac_set_key(entry->hmac, hash,
529 silc_hash_len(silc_hmac_get_hash(entry->hmac)));
530 memset(hash, 0, sizeof(hash));
532 /* Add to the private keys list */
533 silc_dlist_add(channel->private_keys, entry);
535 if (!channel->curr_key)
536 channel->curr_key = entry;
538 /* Free the key material */
539 silc_ske_free_key_material(keymat);
544 /* Removes all private keys from the `channel'. The old channel key is used
545 after calling this to protect the channel messages. Returns FALSE on
546 on error, TRUE otherwise. */
548 int silc_client_del_channel_private_keys(SilcClient client,
549 SilcClientConnection conn,
550 SilcChannelEntry channel)
552 SilcChannelPrivateKey entry;
554 if (!channel->private_keys)
557 silc_dlist_start(channel->private_keys);
558 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
559 silc_dlist_del(channel->private_keys, entry);
560 memset(entry->key, 0, entry->key_len);
561 silc_free(entry->key);
562 silc_cipher_free(entry->cipher);
563 silc_hmac_free(entry->hmac);
567 channel->curr_key = NULL;
569 silc_dlist_uninit(channel->private_keys);
570 channel->private_keys = NULL;
575 /* Removes and frees private key `key' from the channel `channel'. The `key'
576 is retrieved by calling the function silc_client_list_channel_private_keys.
577 The key is not used after this. If the key was last private key then the
578 old channel key is used hereafter to protect the channel messages. This
579 returns FALSE on error, TRUE otherwise. */
581 int silc_client_del_channel_private_key(SilcClient client,
582 SilcClientConnection conn,
583 SilcChannelEntry channel,
584 SilcChannelPrivateKey key)
586 SilcChannelPrivateKey entry;
588 if (!channel->private_keys)
591 silc_dlist_start(channel->private_keys);
592 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
594 if (channel->curr_key == entry)
595 channel->curr_key = NULL;
597 silc_dlist_del(channel->private_keys, entry);
598 memset(entry->key, 0, entry->key_len);
599 silc_free(entry->key);
600 silc_cipher_free(entry->cipher);
601 silc_hmac_free(entry->hmac);
604 if (silc_dlist_count(channel->private_keys) == 0) {
605 silc_dlist_uninit(channel->private_keys);
606 channel->private_keys = NULL;
616 /* Returns array (pointers) of private keys associated to the `channel'.
617 The caller must free the array by calling the function
618 silc_client_free_channel_private_keys. The pointers in the array may be
619 used to delete the specific key by giving the pointer as argument to the
620 function silc_client_del_channel_private_key. */
622 SilcChannelPrivateKey *
623 silc_client_list_channel_private_keys(SilcClient client,
624 SilcClientConnection conn,
625 SilcChannelEntry channel,
628 SilcChannelPrivateKey *keys = NULL, entry;
631 if (!channel->private_keys)
634 silc_dlist_start(channel->private_keys);
635 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
636 keys = silc_realloc(keys, sizeof(*keys) * (count + 1));
647 /* Frees the SilcChannelPrivateKey array. */
649 void silc_client_free_channel_private_keys(SilcChannelPrivateKey *keys,