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))
73 if (chu->mode & SILC_CHANNEL_UMODE_QUIET)
77 /* Take the key to be used */
78 if (channel->mode & SILC_CHANNEL_MODE_PRIVKEY) {
80 /* Use key application specified */
83 } else if (channel->curr_key) {
84 /* Use current private key */
85 cipher = channel->curr_key->cipher;
86 hmac = channel->curr_key->hmac;
87 } else if (!channel->curr_key && channel->private_keys) {
88 /* Use just some private key since we don't know what to use
89 and private keys are set. */
90 silc_dlist_start(channel->private_keys);
91 key = silc_dlist_get(channel->private_keys);
95 /* Use this key as current private key */
96 channel->curr_key = key;
98 /* Use normal channel key generated by the server */
99 cipher = channel->channel_key;
100 hmac = channel->hmac;
103 /* Use normal channel key generated by the server */
104 cipher = channel->channel_key;
105 hmac = channel->hmac;
108 if (!cipher || !hmac)
111 block_len = silc_cipher_get_block_len(cipher);
114 iv_len = silc_cipher_get_block_len(cipher);
115 if (channel->iv[0] == '\0')
116 for (i = 0; i < iv_len; i++) channel->iv[i] =
117 silc_rng_get_byte(client->rng);
119 silc_hash_make(client->internal->md5hash, channel->iv, iv_len,
122 /* Encode the channel payload. This also encrypts the message payload. */
123 payload = silc_channel_message_payload_encode(flags, data_len, data, iv_len,
124 channel->iv, cipher, hmac,
127 /* Get data used in packet header encryption, keys and stuff. */
128 cipher = conn->send_key;
129 hmac = conn->hmac_send;
130 id_string = silc_id_id2str(channel->id, SILC_ID_CHANNEL);
132 /* Set the packet context pointers. The destination ID is always
133 the Channel ID of the channel. Server and router will handle the
134 distribution of the packet. */
135 data = payload->data;
136 data_len = payload->len;
137 packetdata.flags = 0;
138 packetdata.type = SILC_PACKET_CHANNEL_MESSAGE;
139 packetdata.src_id = conn->local_id_data;
140 packetdata.src_id_len = silc_id_get_len(conn->local_id, SILC_ID_CLIENT);
141 packetdata.src_id_type = SILC_ID_CLIENT;
142 packetdata.dst_id = id_string;
143 packetdata.dst_id_len = silc_id_get_len(channel->id, SILC_ID_CHANNEL);
144 packetdata.dst_id_type = SILC_ID_CHANNEL;
145 data_len = SILC_PACKET_DATALEN(data_len, SILC_PACKET_HEADER_LEN +
146 packetdata.src_id_len +
147 packetdata.dst_id_len);
148 packetdata.truelen = data_len + SILC_PACKET_HEADER_LEN +
149 packetdata.src_id_len + packetdata.dst_id_len;
150 packetdata.padlen = SILC_PACKET_PADLEN((SILC_PACKET_HEADER_LEN +
151 packetdata.src_id_len +
152 packetdata.dst_id_len), block_len);
154 /* Create the outgoing packet */
155 if (!silc_packet_assemble(&packetdata, client->rng, cipher, hmac, sock,
156 data, data_len, (const SilcBuffer)&packet)) {
157 SILC_LOG_ERROR(("Error assembling packet"));
161 /* Encrypt the header and padding of the packet. This is encrypted
162 with normal session key shared with our server. */
163 silc_packet_encrypt(cipher, hmac, conn->psn_send++,
164 (SilcBuffer)&packet, SILC_PACKET_HEADER_LEN +
165 packetdata.src_id_len + packetdata.dst_id_len +
168 SILC_LOG_HEXDUMP(("Packet to channel, len %d", packet.len),
169 packet.data, packet.len);
171 /* Now actually send the packet */
172 silc_client_packet_send_real(client, sock, force_send);
175 silc_buffer_free(payload);
176 silc_free(id_string);
180 SilcChannelMessagePayload payload;
181 SilcChannelID *channel_id;
182 } *SilcChannelClientResolve;
184 static void silc_client_channel_message_cb(SilcClient client,
185 SilcClientConnection conn,
186 SilcClientEntry *clients,
187 SilcUInt32 clients_count,
190 SilcChannelClientResolve res = (SilcChannelClientResolve)context;
192 if (clients_count == 1) {
193 SilcChannelEntry channel;
194 unsigned char *message;
195 SilcUInt32 message_len;
197 channel = silc_client_get_channel_by_id(client, conn, res->channel_id);
201 /* If this client is not on channel, add it there since it clearly
203 if (!silc_client_on_channel(channel, clients[0])) {
204 SilcChannelUser chu = silc_calloc(1, sizeof(*chu));
205 chu->client = clients[0];
206 chu->channel = channel;
207 silc_hash_table_add(channel->user_list, clients[0], chu);
208 silc_hash_table_add(clients[0]->channels, channel, chu);
211 message = silc_channel_message_get_data(res->payload, &message_len);
213 /* Pass the message to application */
214 client->internal->ops->channel_message(
215 client, conn, clients[0], channel,
216 silc_channel_message_get_flags(res->payload),
217 message, message_len);
221 silc_channel_message_payload_free(res->payload);
222 silc_free(res->channel_id);
226 /* Process received message to a channel (or from a channel, really). This
227 decrypts the channel message with channel specific key and parses the
228 channel payload. Finally it displays the message on the screen. */
230 void silc_client_channel_message(SilcClient client,
231 SilcSocketConnection sock,
232 SilcPacketContext *packet)
234 SilcClientConnection conn = (SilcClientConnection)sock->user_data;
235 SilcBuffer buffer = packet->buffer;
236 SilcChannelMessagePayload payload = NULL;
237 SilcChannelID *id = NULL;
238 SilcChannelEntry channel;
239 SilcClientEntry client_entry;
240 SilcClientID *client_id = NULL;
241 unsigned char *message;
242 SilcUInt32 message_len;
244 SILC_LOG_DEBUG(("Start"));
247 if (packet->dst_id_type != SILC_ID_CHANNEL)
250 client_id = silc_id_str2id(packet->src_id, packet->src_id_len,
254 id = silc_id_str2id(packet->dst_id, packet->dst_id_len, SILC_ID_CHANNEL);
258 /* Find the channel entry from channels on this connection */
259 channel = silc_client_get_channel_by_id(client, conn, id);
263 /* If there is no channel private key then just decrypt the message
264 with the channel key. If private keys are set then just go through
265 all private keys and check what decrypts correctly. */
266 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY)) {
267 /* Parse the channel message payload. This also decrypts the payload */
268 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
269 channel->channel_key,
272 /* If decryption failed and we have just performed channel key rekey
273 we will use the old key in decryption. If that fails too then we
274 cannot do more and will drop the packet. */
276 if (!channel->old_channel_key) {
280 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
281 channel->old_channel_key,
287 } else if (channel->private_keys) {
288 SilcChannelPrivateKey entry;
290 silc_dlist_start(channel->private_keys);
291 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
292 /* Parse the channel message payload. This also decrypts the payload */
293 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
299 if (entry == SILC_LIST_END)
305 /* Find client entry */
306 client_entry = silc_client_get_client_by_id(client, conn, client_id);
307 if (!client_entry || !client_entry->nickname) {
308 /* Resolve the client info */
309 SilcChannelClientResolve res = silc_calloc(1, sizeof(*res));
310 res->payload = payload;
311 res->channel_id = id;
312 silc_client_get_client_by_id_resolve(client, conn, client_id,
313 silc_client_channel_message_cb,
320 if (!silc_client_on_channel(channel, client_entry)) {
321 SILC_LOG_WARNING(("Received channel message from client not on channel"));
325 message = silc_channel_message_get_data(payload, &message_len);
327 /* Pass the message to application */
328 client->internal->ops->channel_message(
329 client, conn, client_entry, channel,
330 silc_channel_message_get_flags(payload),
331 message, message_len);
335 silc_free(client_id);
337 silc_channel_message_payload_free(payload);
340 /* Timeout callback that is called after a short period of time after the
341 new channel key has been created. This removes the old channel key all
344 SILC_TASK_CALLBACK(silc_client_save_channel_key_rekey)
346 SilcChannelEntry channel = (SilcChannelEntry)context;
348 if (channel->old_channel_key)
349 silc_cipher_free(channel->old_channel_key);
350 if (channel->old_hmac)
351 silc_hmac_free(channel->old_hmac);
352 channel->old_channel_key = NULL;
353 channel->old_hmac = NULL;
354 channel->rekey_task = NULL;
357 /* Saves channel key from encoded `key_payload'. This is used when we
358 receive Channel Key Payload and when we are processing JOIN command
361 void silc_client_save_channel_key(SilcClient client,
362 SilcClientConnection conn,
363 SilcBuffer key_payload,
364 SilcChannelEntry channel)
366 unsigned char *id_string, *key, *cipher, *hmac, hash[32];
369 SilcChannelKeyPayload payload;
371 payload = silc_channel_key_payload_parse(key_payload->data,
376 id_string = silc_channel_key_get_id(payload, &tmp_len);
378 silc_channel_key_payload_free(payload);
382 id = silc_id_str2id(id_string, tmp_len, SILC_ID_CHANNEL);
384 silc_channel_key_payload_free(payload);
390 channel = silc_client_get_channel_by_id(client, conn, id);
395 hmac = (channel->hmac ? (char *)silc_hmac_get_name(channel->hmac) :
398 /* Save the old key for a short period of time so that we can decrypt
399 channel message even after the rekey if some client would be sending
400 messages with the old key after the rekey. */
401 if (channel->old_channel_key)
402 silc_cipher_free(channel->old_channel_key);
403 if (channel->old_hmac)
404 silc_hmac_free(channel->old_hmac);
405 if (channel->rekey_task)
406 silc_schedule_task_del(client->schedule, channel->rekey_task);
407 channel->old_channel_key = channel->channel_key;
408 channel->old_hmac = channel->hmac;
409 channel->rekey_task =
410 silc_schedule_task_add(client->schedule, 0,
411 silc_client_save_channel_key_rekey, channel,
412 10, 0, SILC_TASK_TIMEOUT, SILC_TASK_PRI_NORMAL);
414 /* Free the old channel key data */
415 silc_free(channel->key);
418 key = silc_channel_key_get_key(payload, &tmp_len);
419 cipher = silc_channel_key_get_cipher(payload, NULL);
420 channel->key_len = tmp_len * 8;
421 channel->key = silc_memdup(key, tmp_len);
423 if (!silc_cipher_alloc(cipher, &channel->channel_key)) {
424 client->internal->ops->say(
426 SILC_CLIENT_MESSAGE_AUDIT,
427 "Cannot talk to channel: unsupported cipher %s",
432 /* Set the cipher key */
433 silc_cipher_set_key(channel->channel_key, key, channel->key_len);
435 /* Generate HMAC key from the channel key data and set it */
436 silc_hmac_alloc(hmac, NULL, &channel->hmac);
437 silc_hash_make(silc_hmac_get_hash(channel->hmac), key, tmp_len, hash);
438 silc_hmac_set_key(channel->hmac, hash,
439 silc_hash_len(silc_hmac_get_hash(channel->hmac)));
440 memset(hash, 0, sizeof(hash));
444 silc_channel_key_payload_free(payload);
447 /* Processes received key for channel. The received key will be used
448 to protect the traffic on the channel for now on. Client must receive
449 the key to the channel before talking on the channel is possible.
450 This is the key that server has generated, this is not the channel
451 private key, it is entirely local setting. */
453 void silc_client_receive_channel_key(SilcClient client,
454 SilcSocketConnection sock,
457 SILC_LOG_DEBUG(("Received key for channel"));
460 silc_client_save_channel_key(client, sock->user_data, packet, NULL);
463 /* Adds private key for channel. This may be set only if the channel's mode
464 mask includes the SILC_CHANNEL_MODE_PRIVKEY. This returns FALSE if the
465 mode is not set. When channel has private key then the messages are
466 encrypted using that key. All clients on the channel must also know the
467 key in order to decrypt the messages. However, it is possible to have
468 several private keys per one channel. In this case only some of the
469 clients on the channel may know the one key and only some the other key.
471 If `cipher' and/or `hmac' is NULL then default values will be used
472 (aes-256-cbc for cipher and hmac-sha1-96 for hmac).
474 The private key for channel is optional. If it is not set then the
475 channel messages are encrypted using the channel key generated by the
476 server. However, setting the private key (or keys) for the channel
477 significantly adds security. If more than one key is set the library
478 will automatically try all keys at the message decryption phase. Note:
479 setting many keys slows down the decryption phase as all keys has to
480 be tried in order to find the correct decryption key. However, setting
481 a few keys does not have big impact to the decryption performace.
483 NOTE: that this is entirely local setting. The key set using this function
484 is not sent to the network at any phase.
486 NOTE: If the key material was originated by the SKE protocol (using
487 silc_client_send_key_agreement) then the `key' MUST be the
488 key->send_enc_key as this is dictated by the SILC protocol. However,
489 currently it is not expected that the SKE key material would be used
490 as channel private key. However, this API allows it. */
492 int silc_client_add_channel_private_key(SilcClient client,
493 SilcClientConnection conn,
494 SilcChannelEntry channel,
501 SilcChannelPrivateKey entry;
502 unsigned char hash[32];
503 SilcSKEKeyMaterial *keymat;
505 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY))
509 cipher = SILC_DEFAULT_CIPHER;
511 hmac = SILC_DEFAULT_HMAC;
513 if (!silc_cipher_is_supported(cipher))
516 if (!silc_hmac_is_supported(hmac))
519 /* Produce the key material */
520 keymat = silc_calloc(1, sizeof(*keymat));
521 if (silc_ske_process_key_material_data(key, key_len, 16, 256, 16,
522 client->internal->md5hash, keymat)
523 != SILC_SKE_STATUS_OK)
526 /* Remove the current key, if it exists. */
527 if (channel->channel_key) {
528 silc_cipher_free(channel->channel_key);
529 memset(channel->key, 0, channel->key_len / 8);
530 silc_free(channel->key);
531 channel->channel_key = NULL;
533 channel->key_len = 0;
536 silc_hmac_free(channel->hmac);
537 channel->hmac = NULL;
540 if (!channel->private_keys)
541 channel->private_keys = silc_dlist_init();
544 entry = silc_calloc(1, sizeof(*entry));
545 entry->name = name ? strdup(name) : NULL;
546 entry->key = silc_memdup(keymat->send_enc_key, keymat->enc_key_len / 8);
547 entry->key_len = keymat->enc_key_len / 8;
549 /* Allocate the cipher and set the key*/
550 silc_cipher_alloc(cipher, &entry->cipher);
551 silc_cipher_set_key(entry->cipher, entry->key, keymat->enc_key_len);
553 /* Generate HMAC key from the channel key data and set it */
554 silc_hmac_alloc(hmac, NULL, &entry->hmac);
555 silc_hash_make(silc_hmac_get_hash(entry->hmac), entry->key,
556 entry->key_len, hash);
557 silc_hmac_set_key(entry->hmac, hash,
558 silc_hash_len(silc_hmac_get_hash(entry->hmac)));
559 memset(hash, 0, sizeof(hash));
561 /* Add to the private keys list */
562 silc_dlist_add(channel->private_keys, entry);
564 if (!channel->curr_key)
565 channel->curr_key = entry;
567 /* Free the key material */
568 silc_ske_free_key_material(keymat);
573 /* Removes all private keys from the `channel'. The old channel key is used
574 after calling this to protect the channel messages. Returns FALSE on
575 on error, TRUE otherwise. */
577 int silc_client_del_channel_private_keys(SilcClient client,
578 SilcClientConnection conn,
579 SilcChannelEntry channel)
581 SilcChannelPrivateKey entry;
583 if (!channel->private_keys)
586 silc_dlist_start(channel->private_keys);
587 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
588 silc_dlist_del(channel->private_keys, entry);
589 memset(entry->key, 0, entry->key_len);
590 silc_free(entry->key);
591 silc_free(entry->name);
592 silc_cipher_free(entry->cipher);
593 silc_hmac_free(entry->hmac);
597 channel->curr_key = NULL;
599 silc_dlist_uninit(channel->private_keys);
600 channel->private_keys = NULL;
605 /* Removes and frees private key `key' from the channel `channel'. The `key'
606 is retrieved by calling the function silc_client_list_channel_private_keys.
607 The key is not used after this. If the key was last private key then the
608 old channel key is used hereafter to protect the channel messages. This
609 returns FALSE on error, TRUE otherwise. */
611 int silc_client_del_channel_private_key(SilcClient client,
612 SilcClientConnection conn,
613 SilcChannelEntry channel,
614 SilcChannelPrivateKey key)
616 SilcChannelPrivateKey entry;
618 if (!channel->private_keys)
621 silc_dlist_start(channel->private_keys);
622 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
624 if (channel->curr_key == entry)
625 channel->curr_key = NULL;
627 silc_dlist_del(channel->private_keys, entry);
628 memset(entry->key, 0, entry->key_len);
629 silc_free(entry->key);
630 silc_free(entry->name);
631 silc_cipher_free(entry->cipher);
632 silc_hmac_free(entry->hmac);
635 if (silc_dlist_count(channel->private_keys) == 0) {
636 silc_dlist_uninit(channel->private_keys);
637 channel->private_keys = NULL;
647 /* Returns array (pointers) of private keys associated to the `channel'.
648 The caller must free the array by calling the function
649 silc_client_free_channel_private_keys. The pointers in the array may be
650 used to delete the specific key by giving the pointer as argument to the
651 function silc_client_del_channel_private_key. */
653 SilcChannelPrivateKey *
654 silc_client_list_channel_private_keys(SilcClient client,
655 SilcClientConnection conn,
656 SilcChannelEntry channel,
657 SilcUInt32 *key_count)
659 SilcChannelPrivateKey *keys = NULL, entry;
660 SilcUInt32 count = 0;
662 if (!channel->private_keys)
665 silc_dlist_start(channel->private_keys);
666 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
667 keys = silc_realloc(keys, sizeof(*keys) * (count + 1));
678 /* Frees the SilcChannelPrivateKey array. */
680 void silc_client_free_channel_private_keys(SilcChannelPrivateKey *keys,
681 SilcUInt32 key_count)
686 /* Sets the `key' to be used as current channel private key on the
687 `channel'. Packet sent after calling this function will be secured
690 void silc_client_current_channel_private_key(SilcClient client,
691 SilcClientConnection conn,
692 SilcChannelEntry channel,
693 SilcChannelPrivateKey key)
695 channel->curr_key = key;
698 /* Returns the SilcChannelUser entry if the `client_entry' is joined on the
699 channel indicated by the `channel'. NULL if client is not joined on
702 SilcChannelUser silc_client_on_channel(SilcChannelEntry channel,
703 SilcClientEntry client_entry)
707 if (silc_hash_table_find(channel->user_list, client_entry, NULL,