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->internal->md5hash, channel->iv, iv_len,
101 /* Encode the channel payload. This also encrypts the message payload. */
102 payload = silc_channel_message_payload_encode(flags, data_len, data, iv_len,
103 channel->iv, cipher, hmac);
105 /* Get data used in packet header encryption, keys and stuff. */
106 cipher = conn->send_key;
107 hmac = conn->hmac_send;
108 id_string = silc_id_id2str(channel->id, SILC_ID_CHANNEL);
110 /* Set the packet context pointers. The destination ID is always
111 the Channel ID of the channel. Server and router will handle the
112 distribution of the packet. */
113 packetdata.flags = 0;
114 packetdata.type = SILC_PACKET_CHANNEL_MESSAGE;
115 packetdata.src_id = conn->local_id_data;
116 packetdata.src_id_len = silc_id_get_len(conn->local_id, SILC_ID_CLIENT);
117 packetdata.src_id_type = SILC_ID_CLIENT;
118 packetdata.dst_id = id_string;
119 packetdata.dst_id_len = silc_id_get_len(channel->id, SILC_ID_CHANNEL);
120 packetdata.dst_id_type = SILC_ID_CHANNEL;
121 packetdata.truelen = payload->len + SILC_PACKET_HEADER_LEN +
122 packetdata.src_id_len + packetdata.dst_id_len;
123 packetdata.padlen = SILC_PACKET_PADLEN((SILC_PACKET_HEADER_LEN +
124 packetdata.src_id_len +
125 packetdata.dst_id_len), block_len);
127 /* Prepare outgoing data buffer for packet sending */
128 silc_packet_send_prepare(sock,
129 SILC_PACKET_HEADER_LEN +
130 packetdata.src_id_len +
131 packetdata.dst_id_len,
135 packetdata.buffer = sock->outbuf;
137 /* Put the channel message payload to the outgoing data buffer */
138 silc_buffer_put(sock->outbuf, payload->data, payload->len);
140 /* Create the outgoing packet */
141 silc_packet_assemble(&packetdata, cipher);
143 /* Encrypt the header and padding of the packet. This is encrypted
144 with normal session key shared with our server. */
145 silc_packet_encrypt(cipher, hmac, conn->psn_send++,
146 sock->outbuf, SILC_PACKET_HEADER_LEN +
147 packetdata.src_id_len + packetdata.dst_id_len +
150 SILC_LOG_HEXDUMP(("Packet to channel, len %d", sock->outbuf->len),
151 sock->outbuf->data, sock->outbuf->len);
153 /* Now actually send the packet */
154 silc_client_packet_send_real(client, sock, force_send);
155 silc_buffer_free(payload);
156 silc_free(id_string);
160 SilcChannelMessagePayload payload;
161 SilcChannelID *channel_id;
162 } *SilcChannelClientResolve;
164 static void silc_client_channel_message_cb(SilcClient client,
165 SilcClientConnection conn,
166 SilcClientEntry *clients,
167 uint32 clients_count,
170 SilcChannelClientResolve res = (SilcChannelClientResolve)context;
172 if (clients_count == 1) {
173 SilcChannelEntry channel;
174 unsigned char *message;
176 channel = silc_client_get_channel_by_id(client, conn, res->channel_id);
180 /* If this client is not on channel, add it there since it clearly
182 if (!silc_client_on_channel(channel, clients[0])) {
183 SilcChannelUser chu = silc_calloc(1, sizeof(*chu));
184 chu->client = clients[0];
185 chu->channel = channel;
186 silc_hash_table_add(channel->user_list, clients[0], chu);
187 silc_hash_table_add(clients[0]->channels, channel, chu);
190 message = silc_channel_message_get_data(res->payload, NULL);
192 /* Pass the message to application */
193 client->internal->ops->channel_message(
194 client, conn, clients[0], channel,
195 silc_channel_message_get_flags(res->payload),
200 silc_channel_message_payload_free(res->payload);
201 silc_free(res->channel_id);
205 /* Process received message to a channel (or from a channel, really). This
206 decrypts the channel message with channel specific key and parses the
207 channel payload. Finally it displays the message on the screen. */
209 void silc_client_channel_message(SilcClient client,
210 SilcSocketConnection sock,
211 SilcPacketContext *packet)
213 SilcClientConnection conn = (SilcClientConnection)sock->user_data;
214 SilcBuffer buffer = packet->buffer;
215 SilcChannelMessagePayload payload = NULL;
216 SilcChannelID *id = NULL;
217 SilcChannelEntry channel;
218 SilcClientEntry client_entry;
219 SilcClientID *client_id = NULL;
220 unsigned char *message;
222 SILC_LOG_DEBUG(("Start"));
225 if (packet->dst_id_type != SILC_ID_CHANNEL)
228 client_id = silc_id_str2id(packet->src_id, packet->src_id_len,
232 id = silc_id_str2id(packet->dst_id, packet->dst_id_len, SILC_ID_CHANNEL);
236 /* Find the channel entry from channels on this connection */
237 channel = silc_client_get_channel_by_id(client, conn, id);
241 /* If there is no channel private key then just decrypt the message
242 with the channel key. If private keys are set then just go through
243 all private keys and check what decrypts correctly. */
244 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY)) {
245 /* Parse the channel message payload. This also decrypts the payload */
246 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
247 channel->channel_key,
250 /* If decryption failed and we have just performed channel key rekey
251 we will use the old key in decryption. If that fails too then we
252 cannot do more and will drop the packet. */
254 if (!channel->old_channel_key) {
258 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
259 channel->old_channel_key,
265 } else if (channel->private_keys) {
266 SilcChannelPrivateKey entry;
268 silc_dlist_start(channel->private_keys);
269 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
270 /* Parse the channel message payload. This also decrypts the payload */
271 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
277 if (entry == SILC_LIST_END)
283 /* Find client entry */
284 client_entry = silc_client_get_client_by_id(client, conn, client_id);
285 if (!client_entry || !client_entry->nickname) {
286 /* Resolve the client info */
287 SilcChannelClientResolve res = silc_calloc(1, sizeof(*res));
288 res->payload = payload;
289 res->channel_id = id;
290 silc_client_get_client_by_id_resolve(client, conn, client_id,
291 silc_client_channel_message_cb,
298 if (!silc_client_on_channel(channel, client_entry)) {
299 SILC_LOG_WARNING(("Received channel message from client not on channel"));
303 message = silc_channel_message_get_data(payload, NULL);
305 /* Pass the message to application */
306 client->internal->ops->channel_message(
307 client, conn, client_entry, channel,
308 silc_channel_message_get_flags(payload),
313 silc_free(client_id);
315 silc_channel_message_payload_free(payload);
318 /* Timeout callback that is called after a short period of time after the
319 new channel key has been created. This removes the old channel key all
322 SILC_TASK_CALLBACK(silc_client_save_channel_key_rekey)
324 SilcChannelEntry channel = (SilcChannelEntry)context;
326 if (channel->old_channel_key)
327 silc_cipher_free(channel->old_channel_key);
328 if (channel->old_hmac)
329 silc_hmac_free(channel->old_hmac);
330 channel->old_channel_key = NULL;
331 channel->old_hmac = NULL;
332 channel->rekey_task = NULL;
335 /* Saves channel key from encoded `key_payload'. This is used when we
336 receive Channel Key Payload and when we are processing JOIN command
339 void silc_client_save_channel_key(SilcClient client,
340 SilcClientConnection conn,
341 SilcBuffer key_payload,
342 SilcChannelEntry channel)
344 unsigned char *id_string, *key, *cipher, *hmac, hash[32];
347 SilcChannelKeyPayload payload;
349 payload = silc_channel_key_payload_parse(key_payload->data,
354 id_string = silc_channel_key_get_id(payload, &tmp_len);
356 silc_channel_key_payload_free(payload);
360 id = silc_id_str2id(id_string, tmp_len, SILC_ID_CHANNEL);
362 silc_channel_key_payload_free(payload);
368 channel = silc_client_get_channel_by_id(client, conn, id);
373 hmac = (channel->hmac ? (char *)silc_hmac_get_name(channel->hmac) :
376 /* Save the old key for a short period of time so that we can decrypt
377 channel message even after the rekey if some client would be sending
378 messages with the old key after the rekey. */
379 if (channel->old_channel_key)
380 silc_cipher_free(channel->old_channel_key);
381 if (channel->old_hmac)
382 silc_hmac_free(channel->old_hmac);
383 if (channel->rekey_task)
384 silc_schedule_task_del(client->schedule, channel->rekey_task);
385 channel->old_channel_key = channel->channel_key;
386 channel->old_hmac = channel->hmac;
387 channel->rekey_task =
388 silc_schedule_task_add(client->schedule, 0,
389 silc_client_save_channel_key_rekey, channel,
390 10, 0, SILC_TASK_TIMEOUT, SILC_TASK_PRI_NORMAL);
392 /* Free the old channel key data */
393 silc_free(channel->key);
396 key = silc_channel_key_get_key(payload, &tmp_len);
397 cipher = silc_channel_key_get_cipher(payload, NULL);
398 channel->key_len = tmp_len * 8;
399 channel->key = silc_calloc(tmp_len, sizeof(*channel->key));
400 memcpy(channel->key, key, tmp_len);
402 if (!silc_cipher_alloc(cipher, &channel->channel_key)) {
403 client->internal->ops->say(
405 SILC_CLIENT_MESSAGE_AUDIT,
406 "Cannot talk to channel: unsupported cipher %s",
411 /* Set the cipher key */
412 silc_cipher_set_key(channel->channel_key, key, channel->key_len);
414 /* Generate HMAC key from the channel key data and set it */
415 silc_hmac_alloc(hmac, NULL, &channel->hmac);
416 silc_hash_make(silc_hmac_get_hash(channel->hmac), key, tmp_len, hash);
417 silc_hmac_set_key(channel->hmac, hash,
418 silc_hash_len(silc_hmac_get_hash(channel->hmac)));
419 memset(hash, 0, sizeof(hash));
423 silc_channel_key_payload_free(payload);
426 /* Processes received key for channel. The received key will be used
427 to protect the traffic on the channel for now on. Client must receive
428 the key to the channel before talking on the channel is possible.
429 This is the key that server has generated, this is not the channel
430 private key, it is entirely local setting. */
432 void silc_client_receive_channel_key(SilcClient client,
433 SilcSocketConnection sock,
436 SILC_LOG_DEBUG(("Received key for channel"));
439 silc_client_save_channel_key(client, sock->user_data, packet, NULL);
442 /* Adds private key for channel. This may be set only if the channel's mode
443 mask includes the SILC_CHANNEL_MODE_PRIVKEY. This returns FALSE if the
444 mode is not set. When channel has private key then the messages are
445 encrypted using that key. All clients on the channel must also know the
446 key in order to decrypt the messages. However, it is possible to have
447 several private keys per one channel. In this case only some of the
448 clients on the channel may know the one key and only some the other key.
450 If `cipher' and/or `hmac' is NULL then default values will be used
451 (aes-256-cbc for cipher and hmac-sha1-96 for hmac).
453 The private key for channel is optional. If it is not set then the
454 channel messages are encrypted using the channel key generated by the
455 server. However, setting the private key (or keys) for the channel
456 significantly adds security. If more than one key is set the library
457 will automatically try all keys at the message decryption phase. Note:
458 setting many keys slows down the decryption phase as all keys has to
459 be tried in order to find the correct decryption key. However, setting
460 a few keys does not have big impact to the decryption performace.
462 NOTE: that this is entirely local setting. The key set using this function
463 is not sent to the network at any phase.
465 NOTE: If the key material was originated by the SKE protocol (using
466 silc_client_send_key_agreement) then the `key' MUST be the
467 key->send_enc_key as this is dictated by the SILC protocol. However,
468 currently it is not expected that the SKE key material would be used
469 as channel private key. However, this API allows it. */
471 int silc_client_add_channel_private_key(SilcClient client,
472 SilcClientConnection conn,
473 SilcChannelEntry channel,
479 SilcChannelPrivateKey entry;
480 unsigned char hash[32];
481 SilcSKEKeyMaterial *keymat;
483 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY))
487 cipher = SILC_DEFAULT_CIPHER;
489 hmac = SILC_DEFAULT_HMAC;
491 if (!silc_cipher_is_supported(cipher))
494 if (!silc_hmac_is_supported(hmac))
497 /* Produce the key material */
498 keymat = silc_calloc(1, sizeof(*keymat));
499 if (silc_ske_process_key_material_data(key, key_len, 16, 256, 16,
500 client->internal->md5hash, keymat)
501 != SILC_SKE_STATUS_OK)
504 /* Remove the current key, if it exists. */
505 if (channel->channel_key) {
506 silc_cipher_free(channel->channel_key);
507 memset(channel->key, 0, channel->key_len / 8);
508 silc_free(channel->key);
509 channel->channel_key = NULL;
511 channel->key_len = 0;
514 silc_hmac_free(channel->hmac);
515 channel->hmac = NULL;
518 if (!channel->private_keys)
519 channel->private_keys = silc_dlist_init();
522 entry = silc_calloc(1, sizeof(*entry));
523 entry->key = silc_calloc(keymat->enc_key_len / 8, sizeof(*entry->key));
524 memcpy(entry->key, keymat->send_enc_key, keymat->enc_key_len / 8);
525 entry->key_len = keymat->enc_key_len / 8;
527 /* Allocate the cipher and set the key*/
528 silc_cipher_alloc(cipher, &entry->cipher);
529 silc_cipher_set_key(entry->cipher, entry->key, keymat->enc_key_len);
531 /* Generate HMAC key from the channel key data and set it */
532 silc_hmac_alloc(hmac, NULL, &entry->hmac);
533 silc_hash_make(silc_hmac_get_hash(entry->hmac), entry->key,
534 entry->key_len, hash);
535 silc_hmac_set_key(entry->hmac, hash,
536 silc_hash_len(silc_hmac_get_hash(entry->hmac)));
537 memset(hash, 0, sizeof(hash));
539 /* Add to the private keys list */
540 silc_dlist_add(channel->private_keys, entry);
542 if (!channel->curr_key)
543 channel->curr_key = entry;
545 /* Free the key material */
546 silc_ske_free_key_material(keymat);
551 /* Removes all private keys from the `channel'. The old channel key is used
552 after calling this to protect the channel messages. Returns FALSE on
553 on error, TRUE otherwise. */
555 int silc_client_del_channel_private_keys(SilcClient client,
556 SilcClientConnection conn,
557 SilcChannelEntry channel)
559 SilcChannelPrivateKey entry;
561 if (!channel->private_keys)
564 silc_dlist_start(channel->private_keys);
565 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
566 silc_dlist_del(channel->private_keys, entry);
567 memset(entry->key, 0, entry->key_len);
568 silc_free(entry->key);
569 silc_cipher_free(entry->cipher);
570 silc_hmac_free(entry->hmac);
574 channel->curr_key = NULL;
576 silc_dlist_uninit(channel->private_keys);
577 channel->private_keys = NULL;
582 /* Removes and frees private key `key' from the channel `channel'. The `key'
583 is retrieved by calling the function silc_client_list_channel_private_keys.
584 The key is not used after this. If the key was last private key then the
585 old channel key is used hereafter to protect the channel messages. This
586 returns FALSE on error, TRUE otherwise. */
588 int silc_client_del_channel_private_key(SilcClient client,
589 SilcClientConnection conn,
590 SilcChannelEntry channel,
591 SilcChannelPrivateKey key)
593 SilcChannelPrivateKey entry;
595 if (!channel->private_keys)
598 silc_dlist_start(channel->private_keys);
599 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
601 if (channel->curr_key == entry)
602 channel->curr_key = NULL;
604 silc_dlist_del(channel->private_keys, entry);
605 memset(entry->key, 0, entry->key_len);
606 silc_free(entry->key);
607 silc_cipher_free(entry->cipher);
608 silc_hmac_free(entry->hmac);
611 if (silc_dlist_count(channel->private_keys) == 0) {
612 silc_dlist_uninit(channel->private_keys);
613 channel->private_keys = NULL;
623 /* Returns array (pointers) of private keys associated to the `channel'.
624 The caller must free the array by calling the function
625 silc_client_free_channel_private_keys. The pointers in the array may be
626 used to delete the specific key by giving the pointer as argument to the
627 function silc_client_del_channel_private_key. */
629 SilcChannelPrivateKey *
630 silc_client_list_channel_private_keys(SilcClient client,
631 SilcClientConnection conn,
632 SilcChannelEntry channel,
635 SilcChannelPrivateKey *keys = NULL, entry;
638 if (!channel->private_keys)
641 silc_dlist_start(channel->private_keys);
642 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
643 keys = silc_realloc(keys, sizeof(*keys) * (count + 1));
654 /* Frees the SilcChannelPrivateKey array. */
656 void silc_client_free_channel_private_keys(SilcChannelPrivateKey *keys,
662 /* Returns the SilcChannelUser entry if the `client_entry' is joined on the
663 channel indicated by the `channel'. NULL if client is not joined on
666 SilcChannelUser silc_client_on_channel(SilcChannelEntry channel,
667 SilcClientEntry client_entry)
671 if (silc_hash_table_find(channel->user_list, client_entry, NULL,