5 Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
7 Copyright (C) 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 the Key Agreement packet processing and actual
22 key agreement routines. This file has nothing to do with the actual
23 connection key exchange protocol, it is implemented in the client.c
24 and in protocol.c. This file implements the client-to-client key
25 agreement as defined by the SILC protocol. */
27 #include "clientlibincludes.h"
28 #include "client_internal.h"
30 SILC_TASK_CALLBACK(silc_client_key_agreement_final);
31 SILC_TASK_CALLBACK(silc_client_process_key_agreement);
32 SILC_TASK_CALLBACK(silc_client_key_agreement_timeout);
33 SILC_TASK_CALLBACK(silc_client_perform_key_agreement_start);
35 /* Key agreement context */
36 struct SilcClientKeyAgreementStruct {
38 SilcClientConnection conn;
39 int fd; /* Listening/connection socket */
40 SilcSocketConnection sock; /* Remote socket connection */
41 SilcClientEntry client_entry; /* Destination client */
42 SilcKeyAgreementCallback completion; /* Key agreement completion */
43 void *context; /* User context */
44 SilcTask timeout; /* Timeout task */
45 SilcClientKEInternalContext *proto_ctx; /* Key Exchange protocol context */
48 /* Packet sending function used by the SKE in the key agreement process. */
50 static void silc_client_key_agreement_send_packet(SilcSKE ske,
55 SilcProtocol protocol = (SilcProtocol)context;
56 SilcClientKEInternalContext *ctx =
57 (SilcClientKEInternalContext *)protocol->context;
60 /* Send the packet immediately. We will assure that the packet is not
61 encrypted by setting the socket's user_data pointer to NULL. The
62 silc_client_packet_send would take the keys (wrong keys that is,
63 because user_data is the current SilcClientConnection) from it and
64 we cannot allow that. The packets are never encrypted when doing SKE
65 with another client. */
66 tmp = ske->sock->user_data;
67 ske->sock->user_data = NULL;
68 silc_client_packet_send(ctx->client, ske->sock, type, NULL, 0, NULL, NULL,
69 packet->data, packet->len, TRUE);
70 ske->sock->user_data = tmp;
73 /* Timeout callback that is called to close the connection and free the
74 socket connection data. */
76 SILC_TASK_CALLBACK(silc_client_key_agreement_close)
78 SilcClientKeyAgreement ke = (SilcClientKeyAgreement)context;
80 silc_schedule_unset_listen_fd(ke->client->schedule, ke->sock->sock);
81 silc_schedule_unset_listen_fd(ke->client->schedule, ke->fd);
82 silc_net_close_connection(ke->sock->sock);
83 silc_net_close_connection(ke->fd);
84 silc_socket_free(ke->sock);
88 /* This callback is called after the key agreement protocol has been
89 performed. This calls the final completion callback for the application. */
91 SILC_TASK_CALLBACK(silc_client_key_agreement_final)
93 SilcProtocol protocol = (SilcProtocol)context;
94 SilcClientKEInternalContext *ctx =
95 (SilcClientKEInternalContext *)protocol->context;
96 SilcClient client = (SilcClient)ctx->client;
97 SilcClientKeyAgreement ke = (SilcClientKeyAgreement)ctx->context;
99 SILC_LOG_DEBUG(("Start"));
101 if (protocol->state == SILC_PROTOCOL_STATE_ERROR ||
102 protocol->state == SILC_PROTOCOL_STATE_FAILURE) {
103 /* Error occured during protocol */
104 ke->client_entry->ke = NULL;
105 ke->completion(ke->client, ke->conn, ke->client_entry,
106 SILC_KEY_AGREEMENT_ERROR, NULL, ke->context);
107 silc_ske_free_key_material(ctx->keymat);
111 /* Pass the negotiated key material to the application. The application
112 is responsible of freeing the key material. */
113 ke->client_entry->ke = NULL;
114 ke->completion(ke->client, ke->conn, ke->client_entry,
115 SILC_KEY_AGREEMENT_OK, ctx->keymat, ke->context);
118 silc_protocol_free(protocol);
120 silc_ske_free(ctx->ske);
122 silc_free(ctx->dest_id);
123 silc_task_unregister_by_fd(client->io_queue, ke->fd);
124 silc_schedule_unset_listen_fd(ke->client->schedule, ke->fd);
125 silc_net_close_connection(ke->fd);
127 silc_task_unregister(client->timeout_queue, ke->timeout);
128 silc_client_del_socket(ke->client, ke->sock);
130 silc_task_register(client->timeout_queue, 0,
131 silc_client_key_agreement_close,
133 SILC_TASK_TIMEOUT, SILC_TASK_PRI_NORMAL);
138 /* Key agreement callback that is called when remote end has initiated
139 the key agreement protocol. This accepts the incoming TCP/IP connection
140 for the key agreement protocol. */
142 SILC_TASK_CALLBACK(silc_client_process_key_agreement)
144 SilcClientKeyAgreement ke = (SilcClientKeyAgreement)context;
145 SilcClient client = ke->client;
146 SilcClientConnection conn = ke->conn;
147 SilcSocketConnection newsocket;
148 SilcClientKEInternalContext *proto_ctx;
151 SILC_LOG_DEBUG(("Start"));
153 sock = silc_net_accept_connection(ke->fd);
155 client->ops->say(client, conn,
156 "Could not accept key agreement connection: ",
158 ke->client_entry->ke = NULL;
159 ke->completion(ke->client, ke->conn, ke->client_entry,
160 SILC_KEY_AGREEMENT_ERROR, NULL, ke->context);
161 silc_task_unregister_by_fd(client->io_queue, ke->fd);
162 silc_schedule_unset_listen_fd(ke->client->schedule, ke->fd);
163 silc_net_close_connection(ke->fd);
165 silc_task_unregister(client->timeout_queue, ke->timeout);
170 /* Set socket options */
171 silc_net_set_socket_nonblock(sock);
172 silc_net_set_socket_opt(sock, SOL_SOCKET, SO_REUSEADDR, 1);
174 /* Create socket for this connection (it is of type UNKNOWN since this
175 really is not a real SILC connection. It is only for the key
176 agreement protocol). */
177 silc_socket_alloc(sock, SILC_SOCKET_TYPE_UNKNOWN, (void *)conn, &newsocket);
178 ke->sock = newsocket;
180 /* Perform name and address lookups for the remote host. */
181 silc_net_check_host_by_sock(sock, &newsocket->hostname, &newsocket->ip);
182 if (!newsocket->hostname && !newsocket->ip) {
183 client->ops->say(client, conn,
184 "Could not resolve the remote IP or hostname");
185 ke->client_entry->ke = NULL;
186 ke->completion(ke->client, ke->conn, ke->client_entry,
187 SILC_KEY_AGREEMENT_ERROR, NULL, ke->context);
188 silc_task_unregister_by_fd(client->io_queue, ke->fd);
189 silc_schedule_unset_listen_fd(ke->client->schedule, ke->fd);
190 silc_net_close_connection(ke->fd);
192 silc_task_unregister(client->timeout_queue, ke->timeout);
196 if (!newsocket->hostname)
197 newsocket->hostname = strdup(newsocket->ip);
198 newsocket->port = silc_net_get_remote_port(sock);
199 silc_client_add_socket(client, newsocket);
201 /* Allocate internal context for key exchange protocol. This is
202 sent as context for the protocol. */
203 proto_ctx = silc_calloc(1, sizeof(*proto_ctx));
204 proto_ctx->client = client;
205 proto_ctx->sock = silc_socket_dup(newsocket);
206 proto_ctx->rng = client->rng;
207 proto_ctx->responder = TRUE;
208 proto_ctx->context = context;
209 proto_ctx->send_packet = silc_client_key_agreement_send_packet;
210 proto_ctx->verify = silc_client_protocol_ke_verify_key;
211 ke->proto_ctx = proto_ctx;
213 /* Prepare the connection for key exchange protocol. We allocate the
214 protocol but will not start it yet. The connector will be the
215 initiator of the protocol thus we will wait for initiation from
216 there before we start the protocol. */
217 silc_protocol_alloc(SILC_PROTOCOL_CLIENT_KEY_EXCHANGE,
218 &newsocket->protocol, proto_ctx,
219 silc_client_key_agreement_final);
221 /* Register the connection for network input and output. This sets
222 that scheduler will listen for incoming packets for this connection
223 and sets that outgoing packets may be sent to this connection as well.
224 However, this doesn't set the scheduler for outgoing traffic, it
225 will be set separately by calling SILC_CLIENT_SET_CONNECTION_FOR_OUTPUT,
226 later when outgoing data is available. */
227 context = (void *)client;
228 SILC_CLIENT_REGISTER_CONNECTION_FOR_IO(sock);
231 /* Timeout occured during key agreement. This means that the key agreement
232 protocol was not completed in the specified timeout. We will call the
233 completion callback. */
235 SILC_TASK_CALLBACK(silc_client_key_agreement_timeout)
237 SilcClientKeyAgreement ke = (SilcClientKeyAgreement)context;
239 ke->client_entry->ke = NULL;
240 ke->completion(ke->client, ke->conn, ke->client_entry,
241 SILC_KEY_AGREEMENT_TIMEOUT, NULL, ke->context);
244 silc_client_del_socket(ke->client, ke->sock);
245 silc_socket_free(ke->sock);
247 if (ke->proto_ctx && ke->proto_ctx->ske)
248 silc_ske_free(ke->proto_ctx->ske);
249 ke->client_entry->ke = NULL;
251 silc_task_unregister_by_fd(ke->client->io_queue, ke->fd);
252 silc_schedule_unset_listen_fd(ke->client->schedule, ke->fd);
253 silc_net_close_connection(ke->fd);
257 /* Sends key agreement request to the remote client indicated by the
258 `client_entry'. If the caller provides the `hostname' and the `port'
259 arguments then the library will bind the client to that hostname and
260 that port for the key agreement protocol. It also sends the `hostname'
261 and the `port' in the key agreement packet to the remote client. This
262 would indicate that the remote client may initiate the key agreement
263 protocol to the `hostname' on the `port'. If port is zero then the
264 bound port is undefined (the operating system defines it).
266 If the `hostname' and `port' is not provided then empty key agreement
267 packet is sent to the remote client. The remote client may reply with
268 the same packet including its hostname and port. If the library receives
269 the reply from the remote client the `key_agreement' client operation
270 callback will be called to verify whether the user wants to perform the
271 key agreement or not.
273 NOTE: If the application provided the `hostname' and the `port' and the
274 remote side initiates the key agreement protocol it is not verified
275 from the user anymore whether the protocol should be executed or not.
276 By setting the `hostname' and `port' the user gives permission to
277 perform the protocol (we are responder in this case).
279 NOTE: If the remote side decides not to initiate the key agreement
280 or decides not to reply with the key agreement packet then we cannot
281 perform the key agreement at all. If the key agreement protocol is
282 performed the `completion' callback with the `context' will be called.
283 If remote side decides to ignore the request the `completion' will be
284 called after the specified timeout, `timeout_secs'.
286 NOTE: There can be only one active key agreement for one client entry.
287 Before setting new one, the old one must be finished (it is finished
288 after calling the completion callback) or the function
289 silc_client_abort_key_agreement must be called. */
291 void silc_client_send_key_agreement(SilcClient client,
292 SilcClientConnection conn,
293 SilcClientEntry client_entry,
297 SilcKeyAgreementCallback completion,
300 SilcSocketConnection sock = conn->sock;
301 SilcClientKeyAgreement ke = NULL;
304 assert(client_entry);
306 if (client_entry->ke)
309 /* Create the listener if hostname and port was provided */
311 ke = silc_calloc(1, sizeof(*ke));
312 ke->fd = silc_net_create_server(port, hostname);
315 client->ops->say(client, conn,
316 "Cannot create listener on %s on port %d: %s",
317 hostname, port, strerror(errno));
318 completion(client, conn, client_entry, SILC_KEY_AGREEMENT_FAILURE,
326 ke->client_entry = client_entry;
327 ke->completion = completion;
328 ke->context = context;
330 /* Add listener task to the queue. This task receives the key
332 silc_task_register(client->io_queue, ke->fd,
333 silc_client_process_key_agreement,
336 SILC_TASK_PRI_NORMAL);
338 /* Register a timeout task that will be executed if the connector
339 will not start the key exchange protocol within the specified
341 ke->timeout = silc_task_register(client->timeout_queue, 0,
342 silc_client_key_agreement_timeout,
343 (void *)ke, timeout_secs, 0,
344 SILC_TASK_TIMEOUT, SILC_TASK_PRI_LOW);
347 /* Encode the key agreement payload */
348 buffer = silc_key_agreement_payload_encode(hostname,
350 silc_net_get_local_port(ke->fd));
352 /* Send the key agreement packet to the client */
353 silc_client_packet_send(client, sock, SILC_PACKET_KEY_AGREEMENT,
354 client_entry->id, SILC_ID_CLIENT, NULL, NULL,
355 buffer->data, buffer->len, FALSE);
360 silc_client_connect_to_client_internal(SilcClientInternalConnectContext *ctx)
364 /* Create connection to server asynchronously */
365 sock = silc_net_create_connection_async(ctx->port, ctx->host);
369 /* Register task that will receive the async connect and will
371 ctx->task = silc_task_register(ctx->client->io_queue, sock,
372 silc_client_perform_key_agreement_start,
375 SILC_TASK_PRI_NORMAL);
376 silc_task_reset_iotype(ctx->task, SILC_TASK_WRITE);
377 silc_schedule_set_listen_fd(ctx->client->schedule, sock, ctx->task->iomask);
384 /* Routine used by silc_client_perform_key_agreement to create connection
385 to the remote client on specified port. */
388 silc_client_connect_to_client(SilcClient client,
389 SilcClientConnection conn, int port,
390 char *host, void *context)
392 SilcClientInternalConnectContext *ctx;
394 /* Allocate internal context for connection process. This is
395 needed as we are doing async connecting. */
396 ctx = silc_calloc(1, sizeof(*ctx));
397 ctx->client = client;
399 ctx->host = strdup(host);
402 ctx->context = context;
404 /* Do the actual connecting process */
405 return silc_client_connect_to_client_internal(ctx);
408 /* Callback that is called after connection has been created. This actually
409 starts the key agreement protocol. This is initiator function. */
411 SILC_TASK_CALLBACK(silc_client_perform_key_agreement_start)
413 SilcClientInternalConnectContext *ctx =
414 (SilcClientInternalConnectContext *)context;
415 SilcClient client = ctx->client;
416 SilcClientConnection conn = ctx->conn;
417 SilcClientKeyAgreement ke = (SilcClientKeyAgreement)ctx->context;
418 int opt, opt_len = sizeof(opt);
420 SILC_LOG_DEBUG(("Start"));
422 /* Check the socket status as it might be in error */
423 silc_net_get_socket_opt(fd, SOL_SOCKET, SO_ERROR, &opt, &opt_len);
425 if (ctx->tries < 2) {
426 /* Connection failed but lets try again */
427 client->ops->say(client, conn, "Could not connect to client %s: %s",
428 ctx->host, strerror(opt));
429 client->ops->say(client, conn,
430 "Connecting to port %d of client %s resumed",
431 ctx->port, ctx->host);
433 /* Unregister old connection try */
434 silc_schedule_unset_listen_fd(client->schedule, fd);
435 silc_net_close_connection(fd);
436 silc_task_unregister(client->io_queue, ctx->task);
439 silc_client_connect_to_client_internal(ctx);
442 /* Connection failed and we won't try anymore */
443 client->ops->say(client, conn, "Could not connect to client %s: %s",
444 ctx->host, strerror(opt));
445 silc_schedule_unset_listen_fd(client->schedule, fd);
446 silc_net_close_connection(fd);
447 silc_task_unregister(client->io_queue, ctx->task);
448 silc_free(ctx->host);
451 /* Call the completion callback */
452 ke->completion(ke->client, ke->conn, ke->client_entry,
453 SILC_KEY_AGREEMENT_FAILURE, NULL, ke->context);
459 silc_schedule_unset_listen_fd(client->schedule, fd);
460 silc_task_unregister(client->io_queue, ctx->task);
464 /* Now actually perform the key agreement protocol */
465 silc_client_perform_key_agreement_fd(ke->client, ke->conn,
466 ke->client_entry, ke->fd, ctx->host,
467 ke->completion, ke->context);
469 silc_free(ctx->host);
473 /* Performs the actual key agreement protocol. Application may use this
474 to initiate the key agreement protocol. This can be called for example
475 after the application has received the `key_agreement' client operation,
476 and did not return TRUE from it.
478 The `hostname' is the remote hostname (or IP address) and the `port'
479 is the remote port. The `completion' callback with the `context' will
480 be called after the key agreement protocol.
482 NOTE: If the application returns TRUE in the `key_agreement' client
483 operation the library will automatically start the key agreement. In this
484 case the application must not call this function. However, application
485 may choose to just ignore the `key_agreement' client operation (and
486 merely just print information about it on the screen) and call this
487 function when the user whishes to do so (by, for example, giving some
488 specific command). Thus, the API provides both, automatic and manual
489 initiation of the key agreement. Calling this function is the manual
490 initiation and returning TRUE in the `key_agreement' client operation
491 is the automatic initiation. */
493 void silc_client_perform_key_agreement(SilcClient client,
494 SilcClientConnection conn,
495 SilcClientEntry client_entry,
498 SilcKeyAgreementCallback completion,
501 SilcClientKeyAgreement ke;
503 SILC_LOG_DEBUG(("Start"));
505 assert(client_entry && hostname && port);
507 ke = silc_calloc(1, sizeof(*ke));
510 ke->client_entry = client_entry;
511 ke->completion = completion;
512 ke->context = context;
514 /* Connect to the remote client */
515 ke->fd = silc_client_connect_to_client(client, conn, port, hostname, ke);
517 completion(client, conn, client_entry, SILC_KEY_AGREEMENT_FAILURE,
524 /* Same as above but application has created already the connection to
525 the remote host. The `sock' is the socket to the remote connection.
526 Application can use this function if it does not want the client library
527 to create the connection. */
529 void silc_client_perform_key_agreement_fd(SilcClient client,
530 SilcClientConnection conn,
531 SilcClientEntry client_entry,
534 SilcKeyAgreementCallback completion,
537 SilcClientKeyAgreement ke;
538 SilcClientKEInternalContext *proto_ctx;
539 SilcProtocol protocol;
541 SILC_LOG_DEBUG(("Start"));
543 assert(client_entry);
545 ke = silc_calloc(1, sizeof(*ke));
548 ke->client_entry = client_entry;
550 ke->completion = completion;
551 ke->context = context;
553 /* Allocate new socket connection object */
554 silc_socket_alloc(sock, SILC_SOCKET_TYPE_UNKNOWN, (void *)conn, &ke->sock);
555 silc_client_add_socket(client, ke->sock);
556 ke->sock->hostname = strdup(hostname);
557 ke->sock->port = silc_net_get_remote_port(sock);
559 /* Allocate internal context for key exchange protocol. This is
560 sent as context for the protocol. */
561 proto_ctx = silc_calloc(1, sizeof(*proto_ctx));
562 proto_ctx->client = client;
563 proto_ctx->sock = silc_socket_dup(ke->sock);
564 proto_ctx->rng = client->rng;
565 proto_ctx->responder = FALSE;
566 proto_ctx->context = ke;
567 proto_ctx->send_packet = silc_client_key_agreement_send_packet;
568 proto_ctx->verify = silc_client_protocol_ke_verify_key;
569 ke->proto_ctx = proto_ctx;
571 /* Perform key exchange protocol. */
572 silc_protocol_alloc(SILC_PROTOCOL_CLIENT_KEY_EXCHANGE,
573 &protocol, (void *)proto_ctx,
574 silc_client_key_agreement_final);
575 ke->sock->protocol = protocol;
577 /* Register the connection for network input and output. This sets
578 that scheduler will listen for incoming packets for this connection
579 and sets that outgoing packets may be sent to this connection as well.
580 However, this doesn't set the scheduler for outgoing traffic, it will
581 be set separately by calling SILC_CLIENT_SET_CONNECTION_FOR_OUTPUT,
582 later when outgoing data is available. */
583 context = (void *)client;
584 SILC_CLIENT_REGISTER_CONNECTION_FOR_IO(sock);
586 /* Execute the protocol */
587 silc_protocol_execute(protocol, client->timeout_queue, 0, 0);
590 /* This function can be called to unbind the hostname and the port for
591 the key agreement protocol. However, this function has effect only
592 before the key agreement protocol has been performed. After it has
593 been performed the library will automatically unbind the port. The
594 `client_entry' is the client to which we sent the key agreement
597 void silc_client_abort_key_agreement(SilcClient client,
598 SilcClientConnection conn,
599 SilcClientEntry client_entry)
601 assert(client_entry);
603 if (client_entry->ke) {
604 if (client_entry->ke->sock) {
605 silc_client_del_socket(client_entry->ke->client, client_entry->ke->sock);
606 silc_socket_free(client_entry->ke->sock);
608 client_entry->ke = NULL;
609 silc_task_unregister_by_fd(client->io_queue, client_entry->ke->fd);
610 if (client_entry->ke->timeout)
611 silc_task_unregister(client->timeout_queue,
612 client_entry->ke->timeout);
613 silc_free(client_entry->ke);
617 /* Callback function that is called after we've resolved the client
618 information who sent us the key agreement packet from the server.
619 We actually call the key_agreement client operation now. */
622 silc_client_key_agreement_resolve_cb(SilcClient client,
623 SilcClientConnection conn,
624 SilcClientEntry *clients,
625 uint32 clients_count,
628 SilcPacketContext *packet = (SilcPacketContext *)context;
629 SilcKeyAgreementPayload payload;
631 SilcKeyAgreementCallback completion;
632 void *completion_context;
637 /* Parse the key agreement payload */
638 payload = silc_key_agreement_payload_parse(packet->buffer);
642 /* Call the key_agreement client operation */
643 ret = client->ops->key_agreement(client, conn, clients[0],
644 silc_key_agreement_get_hostname(payload),
645 silc_key_agreement_get_port(payload),
646 &completion, &completion_context);
648 /* If the user returned TRUE then we'll start the key agreement right
649 here and right now. */
651 silc_client_perform_key_agreement(client, conn, clients[0],
652 silc_key_agreement_get_hostname(payload),
653 silc_key_agreement_get_port(payload),
654 completion, completion_context);
656 silc_key_agreement_payload_free(payload);
659 silc_packet_context_free(packet);
662 /* Received Key Agreement packet from remote client. Process the packet
663 and resolve the client information from the server before actually
664 letting the application know that we've received this packet. Then
665 call the key_agreement client operation and let the user decide
666 whether we perform the key agreement protocol now or not. */
668 void silc_client_key_agreement(SilcClient client,
669 SilcSocketConnection sock,
670 SilcPacketContext *packet)
672 SilcClientID *remote_id;
674 if (packet->src_id_type != SILC_ID_CLIENT)
677 remote_id = silc_id_str2id(packet->src_id, packet->src_id_len,
682 silc_client_get_client_by_id_resolve(client, sock->user_data, remote_id,
683 silc_client_key_agreement_resolve_cb,
684 silc_packet_context_dup(packet));
685 silc_free(remote_id);