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 "silcincludes.h"
26 #include "silcclient.h"
27 #include "client_internal.h"
29 /* Sends packet to the `channel'. Packet to channel is always encrypted
30 differently from "normal" packets. SILC header of the packet is
31 encrypted with the next receiver's key and the rest of the packet is
32 encrypted with the channel specific key. Padding and HMAC is computed
33 with the next receiver's key. The `data' is the channel message. If
34 the `force_send' is TRUE then the packet is sent immediately. */
36 void silc_client_send_channel_message(SilcClient client,
37 SilcClientConnection conn,
38 SilcChannelEntry channel,
39 SilcChannelPrivateKey key,
40 SilcMessageFlags flags,
46 SilcSocketConnection sock = conn->sock;
48 SilcPacketContext packetdata;
49 const SilcBufferStruct packet;
52 unsigned char *id_string;
57 SILC_LOG_DEBUG(("Sending packet to channel"));
59 chu = silc_client_on_channel(channel, conn->local_entry);
61 SILC_LOG_ERROR(("Cannot send message to channel we are not joined"));
65 /* Check if it is allowed to send messages to this channel by us. */
66 if (channel->mode & SILC_CHANNEL_MODE_SILENCE_USERS && !chu->mode)
68 if (channel->mode & SILC_CHANNEL_MODE_SILENCE_OPERS &&
69 chu->mode & SILC_CHANNEL_UMODE_CHANOP &&
70 !(chu->mode & SILC_CHANNEL_UMODE_CHANFO))
72 if (chu->mode & SILC_CHANNEL_UMODE_QUIET)
75 /* Take the key to be used */
76 if (channel->mode & SILC_CHANNEL_MODE_PRIVKEY) {
78 /* Use key application specified */
81 } else if (channel->curr_key) {
82 /* Use current private key */
83 cipher = channel->curr_key->cipher;
84 hmac = channel->curr_key->hmac;
85 } else if (!channel->curr_key && channel->private_keys) {
86 /* Use just some private key since we don't know what to use
87 and private keys are set. */
88 silc_dlist_start(channel->private_keys);
89 key = silc_dlist_get(channel->private_keys);
93 /* Use this key as current private key */
94 channel->curr_key = key;
96 /* Use normal channel key generated by the server */
97 cipher = channel->channel_key;
101 /* Use normal channel key generated by the server */
102 cipher = channel->channel_key;
103 hmac = channel->hmac;
106 if (!cipher || !hmac)
109 block_len = silc_cipher_get_block_len(cipher);
112 iv_len = silc_cipher_get_block_len(cipher);
113 if (channel->iv[0] == '\0')
114 for (i = 0; i < iv_len; i++) channel->iv[i] =
115 silc_rng_get_byte(client->rng);
117 silc_hash_make(client->internal->md5hash, channel->iv, iv_len,
120 /* Encode the channel payload. This also encrypts the message payload. */
121 payload = silc_channel_message_payload_encode(flags, data_len, data, iv_len,
122 channel->iv, cipher, hmac,
125 /* Get data used in packet header encryption, keys and stuff. */
126 cipher = conn->send_key;
127 hmac = conn->hmac_send;
128 id_string = silc_id_id2str(channel->id, SILC_ID_CHANNEL);
130 /* Set the packet context pointers. The destination ID is always
131 the Channel ID of the channel. Server and router will handle the
132 distribution of the packet. */
133 data = payload->data;
134 data_len = payload->len;
135 packetdata.flags = 0;
136 packetdata.type = SILC_PACKET_CHANNEL_MESSAGE;
137 packetdata.src_id = conn->local_id_data;
138 packetdata.src_id_len = silc_id_get_len(conn->local_id, SILC_ID_CLIENT);
139 packetdata.src_id_type = SILC_ID_CLIENT;
140 packetdata.dst_id = id_string;
141 packetdata.dst_id_len = silc_id_get_len(channel->id, SILC_ID_CHANNEL);
142 packetdata.dst_id_type = SILC_ID_CHANNEL;
143 data_len = SILC_PACKET_DATALEN(data_len, SILC_PACKET_HEADER_LEN +
144 packetdata.src_id_len +
145 packetdata.dst_id_len);
146 packetdata.truelen = data_len + SILC_PACKET_HEADER_LEN +
147 packetdata.src_id_len + packetdata.dst_id_len;
148 packetdata.padlen = SILC_PACKET_PADLEN((SILC_PACKET_HEADER_LEN +
149 packetdata.src_id_len +
150 packetdata.dst_id_len), block_len);
152 /* Create the outgoing packet */
153 if (!silc_packet_assemble(&packetdata, client->rng, cipher, hmac, sock,
154 data, data_len, (const SilcBuffer)&packet)) {
155 SILC_LOG_ERROR(("Error assembling packet"));
159 /* Encrypt the header and padding of the packet. This is encrypted
160 with normal session key shared with our server. */
161 silc_packet_encrypt(cipher, hmac, conn->psn_send++,
162 (SilcBuffer)&packet, SILC_PACKET_HEADER_LEN +
163 packetdata.src_id_len + packetdata.dst_id_len +
166 SILC_LOG_HEXDUMP(("Packet to channel, len %d", packet.len),
167 packet.data, packet.len);
169 /* Now actually send the packet */
170 silc_client_packet_send_real(client, sock, force_send);
173 silc_buffer_free(payload);
174 silc_free(id_string);
178 SilcChannelMessagePayload payload;
179 SilcChannelID *channel_id;
180 } *SilcChannelClientResolve;
182 static void silc_client_channel_message_cb(SilcClient client,
183 SilcClientConnection conn,
184 SilcClientEntry *clients,
185 SilcUInt32 clients_count,
188 SilcChannelClientResolve res = (SilcChannelClientResolve)context;
190 if (clients_count == 1) {
191 SilcChannelEntry channel;
192 unsigned char *message;
193 SilcUInt32 message_len;
195 channel = silc_client_get_channel_by_id(client, conn, res->channel_id);
199 /* If this client is not on channel, add it there since it clearly
201 if (!silc_client_on_channel(channel, clients[0])) {
202 SilcChannelUser chu = silc_calloc(1, sizeof(*chu));
203 chu->client = clients[0];
204 chu->channel = channel;
205 silc_hash_table_add(channel->user_list, clients[0], chu);
206 silc_hash_table_add(clients[0]->channels, channel, chu);
209 message = silc_channel_message_get_data(res->payload, &message_len);
211 /* Pass the message to application */
212 client->internal->ops->channel_message(
213 client, conn, clients[0], channel,
214 silc_channel_message_get_flags(res->payload),
215 message, message_len);
219 silc_channel_message_payload_free(res->payload);
220 silc_free(res->channel_id);
224 /* Process received message to a channel (or from a channel, really). This
225 decrypts the channel message with channel specific key and parses the
226 channel payload. Finally it displays the message on the screen. */
228 void silc_client_channel_message(SilcClient client,
229 SilcSocketConnection sock,
230 SilcPacketContext *packet)
232 SilcClientConnection conn = (SilcClientConnection)sock->user_data;
233 SilcBuffer buffer = packet->buffer;
234 SilcChannelMessagePayload payload = NULL;
235 SilcChannelID *id = NULL;
236 SilcChannelEntry channel;
237 SilcClientEntry client_entry;
238 SilcClientID *client_id = NULL;
239 unsigned char *message;
240 SilcUInt32 message_len;
242 SILC_LOG_DEBUG(("Start"));
245 if (packet->dst_id_type != SILC_ID_CHANNEL)
248 client_id = silc_id_str2id(packet->src_id, packet->src_id_len,
252 id = silc_id_str2id(packet->dst_id, packet->dst_id_len, SILC_ID_CHANNEL);
256 /* Find the channel entry from channels on this connection */
257 channel = silc_client_get_channel_by_id(client, conn, id);
261 /* If there is no channel private key then just decrypt the message
262 with the channel key. If private keys are set then just go through
263 all private keys and check what decrypts correctly. */
264 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY)) {
265 /* Parse the channel message payload. This also decrypts the payload */
266 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
267 channel->channel_key,
270 /* If decryption failed and we have just performed channel key rekey
271 we will use the old key in decryption. If that fails too then we
272 cannot do more and will drop the packet. */
274 if (!channel->old_channel_key) {
278 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
279 channel->old_channel_key,
285 } else if (channel->private_keys) {
286 SilcChannelPrivateKey entry;
288 silc_dlist_start(channel->private_keys);
289 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
290 /* Parse the channel message payload. This also decrypts the payload */
291 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
297 if (entry == SILC_LIST_END)
303 /* Find client entry */
304 client_entry = silc_client_get_client_by_id(client, conn, client_id);
305 if (!client_entry || !client_entry->nickname ||
306 !silc_client_on_channel(channel, client_entry)) {
307 /* Resolve the client info */
308 SilcChannelClientResolve res = silc_calloc(1, sizeof(*res));
309 res->payload = payload;
310 res->channel_id = id;
311 silc_client_get_client_by_id_resolve(client, conn, client_id,
312 silc_client_channel_message_cb,
319 message = silc_channel_message_get_data(payload, &message_len);
321 /* Pass the message to application */
322 client->internal->ops->channel_message(
323 client, conn, client_entry, channel,
324 silc_channel_message_get_flags(payload),
325 message, message_len);
329 silc_free(client_id);
331 silc_channel_message_payload_free(payload);
334 /* Timeout callback that is called after a short period of time after the
335 new channel key has been created. This removes the old channel key all
338 SILC_TASK_CALLBACK(silc_client_save_channel_key_rekey)
340 SilcChannelEntry channel = (SilcChannelEntry)context;
342 if (channel->old_channel_key)
343 silc_cipher_free(channel->old_channel_key);
344 if (channel->old_hmac)
345 silc_hmac_free(channel->old_hmac);
346 channel->old_channel_key = NULL;
347 channel->old_hmac = NULL;
348 channel->rekey_task = NULL;
351 /* Saves channel key from encoded `key_payload'. This is used when we
352 receive Channel Key Payload and when we are processing JOIN command
355 void silc_client_save_channel_key(SilcClient client,
356 SilcClientConnection conn,
357 SilcBuffer key_payload,
358 SilcChannelEntry channel)
360 unsigned char *id_string, *key, *cipher, *hmac, hash[32];
363 SilcChannelKeyPayload payload;
365 payload = silc_channel_key_payload_parse(key_payload->data,
370 id_string = silc_channel_key_get_id(payload, &tmp_len);
372 silc_channel_key_payload_free(payload);
376 id = silc_id_str2id(id_string, tmp_len, SILC_ID_CHANNEL);
378 silc_channel_key_payload_free(payload);
384 channel = silc_client_get_channel_by_id(client, conn, id);
389 hmac = (channel->hmac ? (char *)silc_hmac_get_name(channel->hmac) :
392 /* Save the old key for a short period of time so that we can decrypt
393 channel message even after the rekey if some client would be sending
394 messages with the old key after the rekey. */
395 if (channel->old_channel_key)
396 silc_cipher_free(channel->old_channel_key);
397 if (channel->old_hmac)
398 silc_hmac_free(channel->old_hmac);
399 if (channel->rekey_task)
400 silc_schedule_task_del(client->schedule, channel->rekey_task);
401 channel->old_channel_key = channel->channel_key;
402 channel->old_hmac = channel->hmac;
403 channel->rekey_task =
404 silc_schedule_task_add(client->schedule, 0,
405 silc_client_save_channel_key_rekey, channel,
406 10, 0, SILC_TASK_TIMEOUT, SILC_TASK_PRI_NORMAL);
408 /* Free the old channel key data */
409 silc_free(channel->key);
412 key = silc_channel_key_get_key(payload, &tmp_len);
413 cipher = silc_channel_key_get_cipher(payload, NULL);
414 channel->key_len = tmp_len * 8;
415 channel->key = silc_memdup(key, tmp_len);
417 if (!silc_cipher_alloc(cipher, &channel->channel_key)) {
418 client->internal->ops->say(
420 SILC_CLIENT_MESSAGE_AUDIT,
421 "Cannot talk to channel: unsupported cipher %s",
426 /* Set the cipher key */
427 silc_cipher_set_key(channel->channel_key, key, channel->key_len);
429 /* Generate HMAC key from the channel key data and set it */
430 silc_hmac_alloc(hmac, NULL, &channel->hmac);
431 silc_hash_make(silc_hmac_get_hash(channel->hmac), key, tmp_len, hash);
432 silc_hmac_set_key(channel->hmac, hash,
433 silc_hash_len(silc_hmac_get_hash(channel->hmac)));
434 memset(hash, 0, sizeof(hash));
438 silc_channel_key_payload_free(payload);
441 /* Processes received key for channel. The received key will be used
442 to protect the traffic on the channel for now on. Client must receive
443 the key to the channel before talking on the channel is possible.
444 This is the key that server has generated, this is not the channel
445 private key, it is entirely local setting. */
447 void silc_client_receive_channel_key(SilcClient client,
448 SilcSocketConnection sock,
451 SILC_LOG_DEBUG(("Received key for channel"));
454 silc_client_save_channel_key(client, sock->user_data, packet, NULL);
457 /* Adds private key for channel. This may be set only if the channel's mode
458 mask includes the SILC_CHANNEL_MODE_PRIVKEY. This returns FALSE if the
459 mode is not set. When channel has private key then the messages are
460 encrypted using that key. All clients on the channel must also know the
461 key in order to decrypt the messages. However, it is possible to have
462 several private keys per one channel. In this case only some of the
463 clients on the channel may know the one key and only some the other key.
465 If `cipher' and/or `hmac' is NULL then default values will be used
466 (aes-256-cbc for cipher and hmac-sha1-96 for hmac).
468 The private key for channel is optional. If it is not set then the
469 channel messages are encrypted using the channel key generated by the
470 server. However, setting the private key (or keys) for the channel
471 significantly adds security. If more than one key is set the library
472 will automatically try all keys at the message decryption phase. Note:
473 setting many keys slows down the decryption phase as all keys has to
474 be tried in order to find the correct decryption key. However, setting
475 a few keys does not have big impact to the decryption performace.
477 NOTE: that this is entirely local setting. The key set using this function
478 is not sent to the network at any phase.
480 NOTE: If the key material was originated by the SKE protocol (using
481 silc_client_send_key_agreement) then the `key' MUST be the
482 key->send_enc_key as this is dictated by the SILC protocol. However,
483 currently it is not expected that the SKE key material would be used
484 as channel private key. However, this API allows it. */
486 int silc_client_add_channel_private_key(SilcClient client,
487 SilcClientConnection conn,
488 SilcChannelEntry channel,
495 SilcChannelPrivateKey entry;
496 unsigned char hash[32];
497 SilcSKEKeyMaterial *keymat;
499 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY))
503 cipher = SILC_DEFAULT_CIPHER;
505 hmac = SILC_DEFAULT_HMAC;
507 if (!silc_cipher_is_supported(cipher))
510 if (!silc_hmac_is_supported(hmac))
513 /* Produce the key material */
514 keymat = silc_calloc(1, sizeof(*keymat));
515 if (silc_ske_process_key_material_data(key, key_len, 16, 256, 16,
516 client->internal->md5hash, keymat)
517 != SILC_SKE_STATUS_OK)
520 /* Remove the current key, if it exists. */
521 if (channel->channel_key) {
522 silc_cipher_free(channel->channel_key);
523 memset(channel->key, 0, channel->key_len / 8);
524 silc_free(channel->key);
525 channel->channel_key = NULL;
527 channel->key_len = 0;
530 silc_hmac_free(channel->hmac);
531 channel->hmac = NULL;
534 if (!channel->private_keys)
535 channel->private_keys = silc_dlist_init();
538 entry = silc_calloc(1, sizeof(*entry));
539 entry->name = name ? strdup(name) : NULL;
540 entry->key = silc_memdup(keymat->send_enc_key, keymat->enc_key_len / 8);
541 entry->key_len = keymat->enc_key_len / 8;
543 /* Allocate the cipher and set the key*/
544 silc_cipher_alloc(cipher, &entry->cipher);
545 silc_cipher_set_key(entry->cipher, entry->key, keymat->enc_key_len);
547 /* Generate HMAC key from the channel key data and set it */
548 silc_hmac_alloc(hmac, NULL, &entry->hmac);
549 silc_hash_make(silc_hmac_get_hash(entry->hmac), entry->key,
550 entry->key_len, hash);
551 silc_hmac_set_key(entry->hmac, hash,
552 silc_hash_len(silc_hmac_get_hash(entry->hmac)));
553 memset(hash, 0, sizeof(hash));
555 /* Add to the private keys list */
556 silc_dlist_add(channel->private_keys, entry);
558 if (!channel->curr_key)
559 channel->curr_key = entry;
561 /* Free the key material */
562 silc_ske_free_key_material(keymat);
567 /* Removes all private keys from the `channel'. The old channel key is used
568 after calling this to protect the channel messages. Returns FALSE on
569 on error, TRUE otherwise. */
571 int silc_client_del_channel_private_keys(SilcClient client,
572 SilcClientConnection conn,
573 SilcChannelEntry channel)
575 SilcChannelPrivateKey entry;
577 if (!channel->private_keys)
580 silc_dlist_start(channel->private_keys);
581 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
582 silc_dlist_del(channel->private_keys, entry);
583 memset(entry->key, 0, entry->key_len);
584 silc_free(entry->key);
585 silc_free(entry->name);
586 silc_cipher_free(entry->cipher);
587 silc_hmac_free(entry->hmac);
591 channel->curr_key = NULL;
593 silc_dlist_uninit(channel->private_keys);
594 channel->private_keys = NULL;
599 /* Removes and frees private key `key' from the channel `channel'. The `key'
600 is retrieved by calling the function silc_client_list_channel_private_keys.
601 The key is not used after this. If the key was last private key then the
602 old channel key is used hereafter to protect the channel messages. This
603 returns FALSE on error, TRUE otherwise. */
605 int silc_client_del_channel_private_key(SilcClient client,
606 SilcClientConnection conn,
607 SilcChannelEntry channel,
608 SilcChannelPrivateKey key)
610 SilcChannelPrivateKey entry;
612 if (!channel->private_keys)
615 silc_dlist_start(channel->private_keys);
616 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
618 if (channel->curr_key == entry)
619 channel->curr_key = NULL;
621 silc_dlist_del(channel->private_keys, entry);
622 memset(entry->key, 0, entry->key_len);
623 silc_free(entry->key);
624 silc_free(entry->name);
625 silc_cipher_free(entry->cipher);
626 silc_hmac_free(entry->hmac);
629 if (silc_dlist_count(channel->private_keys) == 0) {
630 silc_dlist_uninit(channel->private_keys);
631 channel->private_keys = NULL;
641 /* Returns array (pointers) of private keys associated to the `channel'.
642 The caller must free the array by calling the function
643 silc_client_free_channel_private_keys. The pointers in the array may be
644 used to delete the specific key by giving the pointer as argument to the
645 function silc_client_del_channel_private_key. */
647 SilcChannelPrivateKey *
648 silc_client_list_channel_private_keys(SilcClient client,
649 SilcClientConnection conn,
650 SilcChannelEntry channel,
651 SilcUInt32 *key_count)
653 SilcChannelPrivateKey *keys = NULL, entry;
654 SilcUInt32 count = 0;
656 if (!channel->private_keys)
659 silc_dlist_start(channel->private_keys);
660 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
661 keys = silc_realloc(keys, sizeof(*keys) * (count + 1));
672 /* Frees the SilcChannelPrivateKey array. */
674 void silc_client_free_channel_private_keys(SilcChannelPrivateKey *keys,
675 SilcUInt32 key_count)
680 /* Sets the `key' to be used as current channel private key on the
681 `channel'. Packet sent after calling this function will be secured
684 void silc_client_current_channel_private_key(SilcClient client,
685 SilcClientConnection conn,
686 SilcChannelEntry channel,
687 SilcChannelPrivateKey key)
689 channel->curr_key = key;
692 /* Returns the SilcChannelUser entry if the `client_entry' is joined on the
693 channel indicated by the `channel'. NULL if client is not joined on
696 SilcChannelUser silc_client_on_channel(SilcChannelEntry channel,
697 SilcClientEntry client_entry)
701 if (silc_hash_table_find(channel->user_list, client_entry, NULL,