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 message = silc_channel_message_get_data(res->payload, NULL);
182 /* Pass the message to application */
183 client->internal->ops->channel_message(
184 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;
208 SilcClientEntry client_entry;
209 SilcClientID *client_id = NULL;
210 unsigned char *message;
212 SILC_LOG_DEBUG(("Start"));
215 if (packet->dst_id_type != SILC_ID_CHANNEL)
218 client_id = silc_id_str2id(packet->src_id, packet->src_id_len,
222 id = silc_id_str2id(packet->dst_id, packet->dst_id_len, SILC_ID_CHANNEL);
226 /* Find the channel entry from channels on this connection */
227 channel = silc_client_get_channel_by_id(client, conn, id);
231 /* If there is no channel private key then just decrypt the message
232 with the channel key. If private keys are set then just go through
233 all private keys and check what decrypts correctly. */
234 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY)) {
235 /* Parse the channel message payload. This also decrypts the payload */
236 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
237 channel->channel_key,
240 /* If decryption failed and we have just performed channel key rekey
241 we will use the old key in decryption. If that fails too then we
242 cannot do more and will drop the packet. */
244 if (!channel->old_channel_key)
247 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
248 channel->old_channel_key,
253 } else if (channel->private_keys) {
254 SilcChannelPrivateKey entry;
256 silc_dlist_start(channel->private_keys);
257 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
258 /* Parse the channel message payload. This also decrypts the payload */
259 payload = silc_channel_message_payload_parse(buffer->data, buffer->len,
265 if (entry == SILC_LIST_END)
271 /* Find client entry */
272 client_entry = silc_client_get_client_by_id(client, conn, client_id);
273 if (!client_entry || !client_entry->nickname) {
274 /* Resolve the client info */
275 SilcChannelClientResolve res = silc_calloc(1, sizeof(*res));
276 res->payload = payload;
277 res->channel_id = id;
278 silc_client_get_client_by_id_resolve(client, conn, client_id,
279 silc_client_channel_message_cb,
286 if (!silc_client_on_channel(channel, client_entry)) {
287 SILC_LOG_WARNING(("Received channel message from client not on channel"));
291 message = silc_channel_message_get_data(payload, NULL);
293 /* Pass the message to application */
294 client->internal->ops->channel_message(
295 client, conn, client_entry, channel,
296 silc_channel_message_get_flags(payload),
301 silc_free(client_id);
303 silc_channel_message_payload_free(payload);
306 /* Timeout callback that is called after a short period of time after the
307 new channel key has been created. This removes the old channel key all
310 SILC_TASK_CALLBACK(silc_client_save_channel_key_rekey)
312 SilcChannelEntry channel = (SilcChannelEntry)context;
314 if (channel->old_channel_key)
315 silc_cipher_free(channel->old_channel_key);
316 if (channel->old_hmac)
317 silc_hmac_free(channel->old_hmac);
318 channel->old_channel_key = NULL;
319 channel->old_hmac = NULL;
320 channel->rekey_task = NULL;
323 /* Saves channel key from encoded `key_payload'. This is used when we
324 receive Channel Key Payload and when we are processing JOIN command
327 void silc_client_save_channel_key(SilcClient client,
328 SilcClientConnection conn,
329 SilcBuffer key_payload,
330 SilcChannelEntry channel)
332 unsigned char *id_string, *key, *cipher, *hmac, hash[32];
335 SilcChannelKeyPayload payload;
337 payload = silc_channel_key_payload_parse(key_payload->data,
342 id_string = silc_channel_key_get_id(payload, &tmp_len);
344 silc_channel_key_payload_free(payload);
348 id = silc_id_str2id(id_string, tmp_len, SILC_ID_CHANNEL);
350 silc_channel_key_payload_free(payload);
356 channel = silc_client_get_channel_by_id(client, conn, id);
361 hmac = (channel->hmac ? (char *)silc_hmac_get_name(channel->hmac) :
364 /* Save the old key for a short period of time so that we can decrypt
365 channel message even after the rekey if some client would be sending
366 messages with the old key after the rekey. */
367 if (channel->old_channel_key)
368 silc_cipher_free(channel->old_channel_key);
369 if (channel->old_hmac)
370 silc_hmac_free(channel->old_hmac);
371 if (channel->rekey_task)
372 silc_schedule_task_del(client->schedule, channel->rekey_task);
373 channel->old_channel_key = channel->channel_key;
374 channel->old_hmac = channel->hmac;
375 channel->rekey_task =
376 silc_schedule_task_add(client->schedule, 0,
377 silc_client_save_channel_key_rekey, channel,
378 10, 0, SILC_TASK_TIMEOUT, SILC_TASK_PRI_NORMAL);
380 /* Free the old channel key data */
381 silc_free(channel->key);
384 key = silc_channel_key_get_key(payload, &tmp_len);
385 cipher = silc_channel_key_get_cipher(payload, NULL);
386 channel->key_len = tmp_len * 8;
387 channel->key = silc_calloc(tmp_len, sizeof(*channel->key));
388 memcpy(channel->key, key, tmp_len);
390 if (!silc_cipher_alloc(cipher, &channel->channel_key)) {
391 client->internal->ops->say(
393 SILC_CLIENT_MESSAGE_AUDIT,
394 "Cannot talk to channel: unsupported cipher %s",
399 /* Set the cipher key */
400 silc_cipher_set_key(channel->channel_key, key, channel->key_len);
402 /* Generate HMAC key from the channel key data and set it */
403 silc_hmac_alloc(hmac, NULL, &channel->hmac);
404 silc_hash_make(silc_hmac_get_hash(channel->hmac), key, tmp_len, hash);
405 silc_hmac_set_key(channel->hmac, hash,
406 silc_hash_len(silc_hmac_get_hash(channel->hmac)));
407 memset(hash, 0, sizeof(hash));
411 silc_channel_key_payload_free(payload);
414 /* Processes received key for channel. The received key will be used
415 to protect the traffic on the channel for now on. Client must receive
416 the key to the channel before talking on the channel is possible.
417 This is the key that server has generated, this is not the channel
418 private key, it is entirely local setting. */
420 void silc_client_receive_channel_key(SilcClient client,
421 SilcSocketConnection sock,
424 SILC_LOG_DEBUG(("Received key for channel"));
427 silc_client_save_channel_key(client, sock->user_data, packet, NULL);
430 /* Adds private key for channel. This may be set only if the channel's mode
431 mask includes the SILC_CHANNEL_MODE_PRIVKEY. This returns FALSE if the
432 mode is not set. When channel has private key then the messages are
433 encrypted using that key. All clients on the channel must also know the
434 key in order to decrypt the messages. However, it is possible to have
435 several private keys per one channel. In this case only some of the
436 clients on the channel may know the one key and only some the other key.
438 If `cipher' and/or `hmac' is NULL then default values will be used
439 (aes-256-cbc for cipher and hmac-sha1-96 for hmac).
441 The private key for channel is optional. If it is not set then the
442 channel messages are encrypted using the channel key generated by the
443 server. However, setting the private key (or keys) for the channel
444 significantly adds security. If more than one key is set the library
445 will automatically try all keys at the message decryption phase. Note:
446 setting many keys slows down the decryption phase as all keys has to
447 be tried in order to find the correct decryption key. However, setting
448 a few keys does not have big impact to the decryption performace.
450 NOTE: that this is entirely local setting. The key set using this function
451 is not sent to the network at any phase.
453 NOTE: If the key material was originated by the SKE protocol (using
454 silc_client_send_key_agreement) then the `key' MUST be the
455 key->send_enc_key as this is dictated by the SILC protocol. However,
456 currently it is not expected that the SKE key material would be used
457 as channel private key. However, this API allows it. */
459 int silc_client_add_channel_private_key(SilcClient client,
460 SilcClientConnection conn,
461 SilcChannelEntry channel,
467 SilcChannelPrivateKey entry;
468 unsigned char hash[32];
469 SilcSKEKeyMaterial *keymat;
471 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY))
475 cipher = SILC_DEFAULT_CIPHER;
477 hmac = SILC_DEFAULT_HMAC;
479 if (!silc_cipher_is_supported(cipher))
482 if (!silc_hmac_is_supported(hmac))
485 /* Produce the key material */
486 keymat = silc_calloc(1, sizeof(*keymat));
487 if (silc_ske_process_key_material_data(key, key_len, 16, 256, 16,
488 client->internal->md5hash, keymat)
489 != SILC_SKE_STATUS_OK)
492 /* Remove the current key, if it exists. */
493 if (channel->channel_key) {
494 silc_cipher_free(channel->channel_key);
495 memset(channel->key, 0, channel->key_len / 8);
496 silc_free(channel->key);
497 channel->channel_key = NULL;
499 channel->key_len = 0;
502 silc_hmac_free(channel->hmac);
503 channel->hmac = NULL;
506 if (!channel->private_keys)
507 channel->private_keys = silc_dlist_init();
510 entry = silc_calloc(1, sizeof(*entry));
511 entry->key = silc_calloc(keymat->enc_key_len / 8, sizeof(*entry->key));
512 memcpy(entry->key, keymat->send_enc_key, keymat->enc_key_len / 8);
513 entry->key_len = keymat->enc_key_len / 8;
515 /* Allocate the cipher and set the key*/
516 silc_cipher_alloc(cipher, &entry->cipher);
517 silc_cipher_set_key(entry->cipher, entry->key, keymat->enc_key_len);
519 /* Generate HMAC key from the channel key data and set it */
520 silc_hmac_alloc(hmac, NULL, &entry->hmac);
521 silc_hash_make(silc_hmac_get_hash(entry->hmac), entry->key,
522 entry->key_len, hash);
523 silc_hmac_set_key(entry->hmac, hash,
524 silc_hash_len(silc_hmac_get_hash(entry->hmac)));
525 memset(hash, 0, sizeof(hash));
527 /* Add to the private keys list */
528 silc_dlist_add(channel->private_keys, entry);
530 if (!channel->curr_key)
531 channel->curr_key = entry;
533 /* Free the key material */
534 silc_ske_free_key_material(keymat);
539 /* Removes all private keys from the `channel'. The old channel key is used
540 after calling this to protect the channel messages. Returns FALSE on
541 on error, TRUE otherwise. */
543 int silc_client_del_channel_private_keys(SilcClient client,
544 SilcClientConnection conn,
545 SilcChannelEntry channel)
547 SilcChannelPrivateKey entry;
549 if (!channel->private_keys)
552 silc_dlist_start(channel->private_keys);
553 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
554 silc_dlist_del(channel->private_keys, entry);
555 memset(entry->key, 0, entry->key_len);
556 silc_free(entry->key);
557 silc_cipher_free(entry->cipher);
558 silc_hmac_free(entry->hmac);
562 channel->curr_key = NULL;
564 silc_dlist_uninit(channel->private_keys);
565 channel->private_keys = NULL;
570 /* Removes and frees private key `key' from the channel `channel'. The `key'
571 is retrieved by calling the function silc_client_list_channel_private_keys.
572 The key is not used after this. If the key was last private key then the
573 old channel key is used hereafter to protect the channel messages. This
574 returns FALSE on error, TRUE otherwise. */
576 int silc_client_del_channel_private_key(SilcClient client,
577 SilcClientConnection conn,
578 SilcChannelEntry channel,
579 SilcChannelPrivateKey key)
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) {
589 if (channel->curr_key == entry)
590 channel->curr_key = NULL;
592 silc_dlist_del(channel->private_keys, entry);
593 memset(entry->key, 0, entry->key_len);
594 silc_free(entry->key);
595 silc_cipher_free(entry->cipher);
596 silc_hmac_free(entry->hmac);
599 if (silc_dlist_count(channel->private_keys) == 0) {
600 silc_dlist_uninit(channel->private_keys);
601 channel->private_keys = NULL;
611 /* Returns array (pointers) of private keys associated to the `channel'.
612 The caller must free the array by calling the function
613 silc_client_free_channel_private_keys. The pointers in the array may be
614 used to delete the specific key by giving the pointer as argument to the
615 function silc_client_del_channel_private_key. */
617 SilcChannelPrivateKey *
618 silc_client_list_channel_private_keys(SilcClient client,
619 SilcClientConnection conn,
620 SilcChannelEntry channel,
623 SilcChannelPrivateKey *keys = NULL, entry;
626 if (!channel->private_keys)
629 silc_dlist_start(channel->private_keys);
630 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
631 keys = silc_realloc(keys, sizeof(*keys) * (count + 1));
642 /* Frees the SilcChannelPrivateKey array. */
644 void silc_client_free_channel_private_keys(SilcChannelPrivateKey *keys,
650 /* Returns the SilcChannelUser entry if the `client_entry' is joined on the
651 channel indicated by the `channel'. NULL if client is not joined on
654 SilcChannelUser silc_client_on_channel(SilcChannelEntry channel,
655 SilcClientEntry client_entry)
659 if (silc_hash_table_find(channel->user_list, client_entry, NULL,