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;
53 SILC_LOG_DEBUG(("Sending packet to channel"));
55 /* Take the key to be used */
56 if (channel->mode & SILC_CHANNEL_MODE_PRIVKEY) {
58 /* Use key application specified */
61 } else if (channel->curr_key) {
62 /* Use current private key */
63 cipher = channel->curr_key->cipher;
64 hmac = channel->curr_key->hmac;
65 } else if (!channel->curr_key && channel->private_keys) {
66 /* Use just some private key since we don't know what to use
67 and private keys are set. */
68 silc_dlist_start(channel->private_keys);
69 key = silc_dlist_get(channel->private_keys);
73 /* Use this key as current private key */
74 channel->curr_key = key;
76 /* Use normal channel key generated by the server */
77 cipher = channel->channel_key;
81 /* Use normal channel key generated by the server */
82 cipher = channel->channel_key;
90 iv_len = silc_cipher_get_block_len(cipher);
91 if (channel->iv[0] == '\0')
92 for (i = 0; i < iv_len; i++) channel->iv[i] =
93 silc_rng_get_byte(client->rng);
95 silc_hash_make(client->md5hash, channel->iv, iv_len, channel->iv);
97 /* Encode the channel payload. This also encrypts the message payload. */
98 payload = silc_channel_message_payload_encode(flags, data_len, data, iv_len,
99 channel->iv, cipher, hmac);
101 /* Get data used in packet header encryption, keys and stuff. */
102 cipher = conn->send_key;
103 hmac = conn->hmac_send;
104 id_string = silc_id_id2str(channel->id, SILC_ID_CHANNEL);
106 /* Set the packet context pointers. The destination ID is always
107 the Channel ID of the channel. Server and router will handle the
108 distribution of the packet. */
109 packetdata.flags = 0;
110 packetdata.type = SILC_PACKET_CHANNEL_MESSAGE;
111 packetdata.src_id = conn->local_id_data;
112 packetdata.src_id_len = silc_id_get_len(conn->local_id, SILC_ID_CLIENT);
113 packetdata.src_id_type = SILC_ID_CLIENT;
114 packetdata.dst_id = id_string;
115 packetdata.dst_id_len = silc_id_get_len(channel->id, SILC_ID_CHANNEL);
116 packetdata.dst_id_type = SILC_ID_CHANNEL;
117 packetdata.truelen = payload->len + SILC_PACKET_HEADER_LEN +
118 packetdata.src_id_len + packetdata.dst_id_len;
119 packetdata.padlen = SILC_PACKET_PADLEN((SILC_PACKET_HEADER_LEN +
120 packetdata.src_id_len +
121 packetdata.dst_id_len));
123 /* Prepare outgoing data buffer for packet sending */
124 silc_packet_send_prepare(sock,
125 SILC_PACKET_HEADER_LEN +
126 packetdata.src_id_len +
127 packetdata.dst_id_len,
131 packetdata.buffer = sock->outbuf;
133 /* Put the channel message payload to the outgoing data buffer */
134 silc_buffer_put(sock->outbuf, payload->data, payload->len);
136 /* Create the outgoing packet */
137 silc_packet_assemble(&packetdata);
139 /* Encrypt the header and padding of the packet. This is encrypted
140 with normal session key shared with our server. */
141 silc_packet_encrypt(cipher, hmac, sock->outbuf, SILC_PACKET_HEADER_LEN +
142 packetdata.src_id_len + packetdata.dst_id_len +
145 SILC_LOG_HEXDUMP(("Packet to channel, len %d", sock->outbuf->len),
146 sock->outbuf->data, sock->outbuf->len);
148 /* Now actually send the packet */
149 silc_client_packet_send_real(client, sock, force_send, FALSE);
150 silc_buffer_free(payload);
151 silc_free(id_string);
154 static void silc_client_channel_message_cb(SilcClient client,
155 SilcClientConnection conn,
156 SilcClientEntry *clients,
157 uint32 clients_count,
160 SilcPacketContext *packet = (SilcPacketContext *)context;
163 silc_client_channel_message(client, conn->sock, packet);
164 silc_packet_context_free(packet);
167 /* Process received message to a channel (or from a channel, really). This
168 decrypts the channel message with channel specific key and parses the
169 channel payload. Finally it displays the message on the screen. */
171 void silc_client_channel_message(SilcClient client,
172 SilcSocketConnection sock,
173 SilcPacketContext *packet)
175 SilcClientConnection conn = (SilcClientConnection)sock->user_data;
176 SilcBuffer buffer = packet->buffer;
177 SilcChannelMessagePayload payload = NULL;
178 SilcChannelID *id = NULL;
179 SilcChannelEntry channel;
181 SilcIDCacheEntry id_cache = NULL;
182 SilcClientID *client_id = NULL;
184 unsigned char *message;
186 SILC_LOG_DEBUG(("Start"));
189 if (packet->dst_id_type != SILC_ID_CHANNEL)
192 client_id = silc_id_str2id(packet->src_id, packet->src_id_len,
196 id = silc_id_str2id(packet->dst_id, packet->dst_id_len, SILC_ID_CHANNEL);
200 /* Find the channel entry from channels on this connection */
201 if (!silc_idcache_find_by_id_one(conn->channel_cache, (void *)id, &id_cache))
204 channel = (SilcChannelEntry)id_cache->context;
206 /* If there is no channel private key then just decrypt the message
207 with the channel key. If private keys are set then just go through
208 all private keys and check what decrypts correctly. */
209 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY)) {
210 /* Parse the channel message payload. This also decrypts the payload */
211 payload = silc_channel_message_payload_parse(buffer, channel->channel_key,
215 } else if (channel->private_keys) {
216 SilcChannelPrivateKey entry;
218 silc_dlist_start(channel->private_keys);
219 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
220 /* Parse the channel message payload. This also decrypts the payload */
221 payload = silc_channel_message_payload_parse(buffer, entry->cipher,
226 if (entry == SILC_LIST_END)
232 /* Find client entry */
233 silc_list_start(channel->clients);
234 while ((chu = silc_list_get(channel->clients)) != SILC_LIST_END) {
235 if (SILC_ID_CLIENT_COMPARE(chu->client->id, client_id)) {
242 /* Resolve the client info */
243 silc_client_get_client_by_id_resolve(client, conn, client_id,
244 silc_client_channel_message_cb,
245 silc_packet_context_dup(packet));
249 message = silc_channel_message_get_data(payload, NULL);
251 /* Pass the message to application */
252 client->ops->channel_message(client, conn, chu->client, channel,
253 silc_channel_message_get_flags(payload),
260 silc_free(client_id);
262 silc_channel_message_payload_free(payload);
265 /* Saves channel key from encoded `key_payload'. This is used when we
266 receive Channel Key Payload and when we are processing JOIN command
269 void silc_client_save_channel_key(SilcClientConnection conn,
270 SilcBuffer key_payload,
271 SilcChannelEntry channel)
273 unsigned char *id_string, *key, *cipher, hash[32];
276 SilcIDCacheEntry id_cache = NULL;
277 SilcChannelKeyPayload payload;
279 payload = silc_channel_key_payload_parse(key_payload);
283 id_string = silc_channel_key_get_id(payload, &tmp_len);
285 silc_channel_key_payload_free(payload);
289 id = silc_id_str2id(id_string, tmp_len, SILC_ID_CHANNEL);
291 silc_channel_key_payload_free(payload);
297 if (!silc_idcache_find_by_id_one(conn->channel_cache,
298 (void *)id, &id_cache))
301 /* Get channel entry */
302 channel = (SilcChannelEntry)id_cache->context;
306 key = silc_channel_key_get_key(payload, &tmp_len);
307 cipher = silc_channel_key_get_cipher(payload, NULL);
308 channel->key_len = tmp_len * 8;
309 channel->key = silc_calloc(tmp_len, sizeof(*channel->key));
310 memcpy(channel->key, key, tmp_len);
312 if (!silc_cipher_alloc(cipher, &channel->channel_key)) {
313 conn->client->ops->say(conn->client, conn,
314 "Cannot talk to channel: unsupported cipher %s", cipher);
318 /* Set the cipher key */
319 silc_cipher_set_key(channel->channel_key, key, channel->key_len);
321 /* Generate HMAC key from the channel key data and set it */
323 silc_hmac_alloc("hmac-sha1-96", NULL, &channel->hmac);
324 silc_hash_make(channel->hmac->hash, key, tmp_len, hash);
325 silc_hmac_set_key(channel->hmac, hash, silc_hash_len(channel->hmac->hash));
326 memset(hash, 0, sizeof(hash));
330 silc_channel_key_payload_free(payload);
333 /* Processes received key for channel. The received key will be used
334 to protect the traffic on the channel for now on. Client must receive
335 the key to the channel before talking on the channel is possible.
336 This is the key that server has generated, this is not the channel
337 private key, it is entirely local setting. */
339 void silc_client_receive_channel_key(SilcClient client,
340 SilcSocketConnection sock,
343 SILC_LOG_DEBUG(("Received key for channel"));
346 silc_client_save_channel_key(sock->user_data, packet, NULL);
349 /* Adds private key for channel. This may be set only if the channel's mode
350 mask includes the SILC_CHANNEL_MODE_PRIVKEY. This returns FALSE if the
351 mode is not set. When channel has private key then the messages are
352 encrypted using that key. All clients on the channel must also know the
353 key in order to decrypt the messages. However, it is possible to have
354 several private keys per one channel. In this case only some of the
355 clients on the channel may know the one key and only some the other key.
357 If `cipher' and/or `hmac' is NULL then default values will be used
358 (aes-256-cbc for cipher and hmac-sha1-96 for hmac).
360 The private key for channel is optional. If it is not set then the
361 channel messages are encrypted using the channel key generated by the
362 server. However, setting the private key (or keys) for the channel
363 significantly adds security. If more than one key is set the library
364 will automatically try all keys at the message decryption phase. Note:
365 setting many keys slows down the decryption phase as all keys has to
366 be tried in order to find the correct decryption key. However, setting
367 a few keys does not have big impact to the decryption performace.
369 NOTE: that this is entirely local setting. The key set using this function
370 is not sent to the network at any phase.
372 NOTE: If the key material was originated by the SKE protocol (using
373 silc_client_send_key_agreement) then the `key' MUST be the
374 key->send_enc_key as this is dictated by the SILC protocol. However,
375 currently it is not expected that the SKE key material would be used
376 as channel private key. However, this API allows it. */
378 int silc_client_add_channel_private_key(SilcClient client,
379 SilcClientConnection conn,
380 SilcChannelEntry channel,
386 SilcChannelPrivateKey entry;
387 unsigned char hash[32];
388 SilcSKEKeyMaterial *keymat;
390 if (!(channel->mode & SILC_CHANNEL_MODE_PRIVKEY))
394 cipher = "aes-256-cbc";
396 hmac = "hmac-sha1-96";
398 if (!silc_cipher_is_supported(cipher))
401 if (!silc_hmac_is_supported(hmac))
404 /* Produce the key material */
405 keymat = silc_calloc(1, sizeof(*keymat));
406 if (silc_ske_process_key_material_data(key, key_len, 16, 256, 16,
407 client->md5hash, keymat)
408 != SILC_SKE_STATUS_OK)
411 /* Remove the current key, if it exists. */
412 if (channel->channel_key) {
413 silc_cipher_free(channel->channel_key);
414 memset(channel->key, 0, channel->key_len / 8);
415 silc_free(channel->key);
416 channel->channel_key = NULL;
418 channel->key_len = 0;
421 silc_hmac_free(channel->hmac);
422 channel->hmac = NULL;
425 if (!channel->private_keys)
426 channel->private_keys = silc_dlist_init();
429 entry = silc_calloc(1, sizeof(*entry));
430 entry->key = silc_calloc(keymat->enc_key_len / 8, sizeof(*entry->key));
431 memcpy(entry->key, keymat->send_enc_key, keymat->enc_key_len / 8);
432 entry->key_len = keymat->enc_key_len / 8;
434 /* Allocate the cipher and set the key*/
435 silc_cipher_alloc(cipher, &entry->cipher);
436 silc_cipher_set_key(entry->cipher, entry->key, keymat->enc_key_len);
438 /* Generate HMAC key from the channel key data and set it */
439 silc_hmac_alloc(hmac, NULL, &entry->hmac);
440 silc_hash_make(entry->hmac->hash, entry->key, entry->key_len, hash);
441 silc_hmac_set_key(entry->hmac, hash, silc_hash_len(entry->hmac->hash));
442 memset(hash, 0, sizeof(hash));
444 /* Add to the private keys list */
445 silc_dlist_add(channel->private_keys, entry);
447 if (!channel->curr_key)
448 channel->curr_key = entry;
450 /* Free the key material */
451 silc_ske_free_key_material(keymat);
456 /* Removes all private keys from the `channel'. The old channel key is used
457 after calling this to protect the channel messages. Returns FALSE on
458 on error, TRUE otherwise. */
460 int silc_client_del_channel_private_keys(SilcClient client,
461 SilcClientConnection conn,
462 SilcChannelEntry channel)
464 SilcChannelPrivateKey entry;
466 if (!channel->private_keys)
469 silc_dlist_start(channel->private_keys);
470 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
471 silc_dlist_del(channel->private_keys, entry);
472 memset(entry->key, 0, entry->key_len);
473 silc_free(entry->key);
474 silc_cipher_free(entry->cipher);
475 silc_hmac_free(entry->hmac);
479 channel->curr_key = NULL;
481 silc_dlist_uninit(channel->private_keys);
482 channel->private_keys = NULL;
487 /* Removes and frees private key `key' from the channel `channel'. The `key'
488 is retrieved by calling the function silc_client_list_channel_private_keys.
489 The key is not used after this. If the key was last private key then the
490 old channel key is used hereafter to protect the channel messages. This
491 returns FALSE on error, TRUE otherwise. */
493 int silc_client_del_channel_private_key(SilcClient client,
494 SilcClientConnection conn,
495 SilcChannelEntry channel,
496 SilcChannelPrivateKey key)
498 SilcChannelPrivateKey entry;
500 if (!channel->private_keys)
503 silc_dlist_start(channel->private_keys);
504 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
506 if (channel->curr_key == entry)
507 channel->curr_key = NULL;
509 silc_dlist_del(channel->private_keys, entry);
510 memset(entry->key, 0, entry->key_len);
511 silc_free(entry->key);
512 silc_cipher_free(entry->cipher);
513 silc_hmac_free(entry->hmac);
516 if (silc_dlist_count(channel->private_keys) == 0) {
517 silc_dlist_uninit(channel->private_keys);
518 channel->private_keys = NULL;
528 /* Returns array (pointers) of private keys associated to the `channel'.
529 The caller must free the array by calling the function
530 silc_client_free_channel_private_keys. The pointers in the array may be
531 used to delete the specific key by giving the pointer as argument to the
532 function silc_client_del_channel_private_key. */
534 SilcChannelPrivateKey *
535 silc_client_list_channel_private_keys(SilcClient client,
536 SilcClientConnection conn,
537 SilcChannelEntry channel,
540 SilcChannelPrivateKey *keys = NULL, entry;
543 if (!channel->private_keys)
546 silc_dlist_start(channel->private_keys);
547 while ((entry = silc_dlist_get(channel->private_keys)) != SILC_LIST_END) {
548 keys = silc_realloc(keys, sizeof(*keys) * (count + 1));
559 /* Frees the SilcChannelPrivateKey array. */
561 void silc_client_free_channel_private_keys(SilcChannelPrivateKey *keys,