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 "silcincludes.h"
28 #include "silcclient.h"
29 #include "client_internal.h"
31 SILC_TASK_CALLBACK(silc_client_key_agreement_final);
32 SILC_TASK_CALLBACK(silc_client_process_key_agreement);
33 SILC_TASK_CALLBACK(silc_client_key_agreement_timeout);
34 SILC_TASK_CALLBACK(silc_client_perform_key_agreement_start);
36 /* Key agreement context */
37 struct SilcClientKeyAgreementStruct {
39 SilcClientConnection conn;
40 int fd; /* Listening/connection socket */
41 SilcSocketConnection sock; /* Remote socket connection */
42 SilcClientEntry client_entry; /* Destination client */
43 SilcKeyAgreementCallback completion; /* Key agreement completion */
44 void *context; /* User context */
45 SilcTask timeout; /* Timeout task */
46 SilcClientKEInternalContext *proto_ctx; /* Key Exchange protocol context */
49 /* Packet sending function used by the SKE in the key agreement process. */
51 static void silc_client_key_agreement_send_packet(SilcSKE ske,
56 SilcProtocol protocol = (SilcProtocol)context;
57 SilcClientKEInternalContext *ctx =
58 (SilcClientKEInternalContext *)protocol->context;
61 /* Send the packet immediately. We will assure that the packet is not
62 encrypted by setting the socket's user_data pointer to NULL. The
63 silc_client_packet_send would take the keys (wrong keys that is,
64 because user_data is the current SilcClientConnection) from it and
65 we cannot allow that. The packets are never encrypted when doing SKE
66 with another client. */
67 tmp = ske->sock->user_data;
68 ske->sock->user_data = NULL;
69 silc_client_packet_send(ctx->client, ske->sock, type, NULL, 0, NULL, NULL,
70 packet->data, packet->len, TRUE);
71 ske->sock->user_data = tmp;
74 /* Timeout callback that is called to close the connection and free the
75 socket connection data. */
77 SILC_TASK_CALLBACK(silc_client_key_agreement_close)
79 SilcClientKeyAgreement ke = (SilcClientKeyAgreement)context;
81 silc_schedule_unset_listen_fd(ke->client->schedule, ke->sock->sock);
82 silc_schedule_unset_listen_fd(ke->client->schedule, ke->fd);
83 silc_net_close_connection(ke->sock->sock);
84 silc_net_close_connection(ke->fd);
85 silc_socket_free(ke->sock);
89 /* This callback is called after the key agreement protocol has been
90 performed. This calls the final completion callback for the application. */
92 SILC_TASK_CALLBACK(silc_client_key_agreement_final)
94 SilcProtocol protocol = (SilcProtocol)context;
95 SilcClientKEInternalContext *ctx =
96 (SilcClientKEInternalContext *)protocol->context;
97 SilcClient client = (SilcClient)ctx->client;
98 SilcClientKeyAgreement ke = (SilcClientKeyAgreement)ctx->context;
100 SILC_LOG_DEBUG(("Start"));
102 if (protocol->state == SILC_PROTOCOL_STATE_ERROR ||
103 protocol->state == SILC_PROTOCOL_STATE_FAILURE) {
104 /* Error occured during protocol */
105 ke->client_entry->ke = NULL;
106 ke->completion(ke->client, ke->conn, ke->client_entry,
107 SILC_KEY_AGREEMENT_ERROR, NULL, ke->context);
108 silc_ske_free_key_material(ctx->keymat);
112 /* Pass the negotiated key material to the application. The application
113 is responsible of freeing the key material. */
114 ke->client_entry->ke = NULL;
115 ke->completion(ke->client, ke->conn, ke->client_entry,
116 SILC_KEY_AGREEMENT_OK, ctx->keymat, ke->context);
119 silc_protocol_free(protocol);
121 silc_ske_free(ctx->ske);
123 silc_free(ctx->dest_id);
124 silc_schedule_task_del_by_fd(client->schedule, ke->fd);
125 silc_schedule_unset_listen_fd(ke->client->schedule, ke->fd);
126 silc_net_close_connection(ke->fd);
128 silc_schedule_task_del(client->schedule, ke->timeout);
129 silc_client_del_socket(ke->client, ke->sock);
131 silc_schedule_task_add(client->schedule, 0,
132 silc_client_key_agreement_close,
134 SILC_TASK_TIMEOUT, SILC_TASK_PRI_NORMAL);
139 /* Key agreement callback that is called when remote end has initiated
140 the key agreement protocol. This accepts the incoming TCP/IP connection
141 for the key agreement protocol. */
143 SILC_TASK_CALLBACK(silc_client_process_key_agreement)
145 SilcClientKeyAgreement ke = (SilcClientKeyAgreement)context;
146 SilcClient client = ke->client;
147 SilcClientConnection conn = ke->conn;
148 SilcSocketConnection newsocket;
149 SilcClientKEInternalContext *proto_ctx;
152 SILC_LOG_DEBUG(("Start"));
154 sock = silc_net_accept_connection(ke->fd);
156 client->internal->ops->say(client, conn, SILC_CLIENT_MESSAGE_AUDIT,
157 "Could not accept key agreement connection: ",
159 ke->client_entry->ke = NULL;
160 ke->completion(ke->client, ke->conn, ke->client_entry,
161 SILC_KEY_AGREEMENT_ERROR, NULL, ke->context);
162 silc_schedule_task_del_by_fd(client->schedule, ke->fd);
163 silc_schedule_unset_listen_fd(ke->client->schedule, ke->fd);
164 silc_net_close_connection(ke->fd);
166 silc_schedule_task_del(client->schedule, ke->timeout);
171 /* Set socket options */
172 silc_net_set_socket_nonblock(sock);
173 silc_net_set_socket_opt(sock, SOL_SOCKET, SO_REUSEADDR, 1);
175 /* Create socket for this connection (it is of type UNKNOWN since this
176 really is not a real SILC connection. It is only for the key
177 agreement protocol). */
178 silc_socket_alloc(sock, SILC_SOCKET_TYPE_UNKNOWN, (void *)conn, &newsocket);
179 ke->sock = newsocket;
181 /* Perform name and address lookups for the remote host. */
182 silc_net_check_host_by_sock(sock, &newsocket->hostname, &newsocket->ip);
183 if (!newsocket->hostname && !newsocket->ip) {
184 client->internal->ops->say(client, conn, SILC_CLIENT_MESSAGE_AUDIT,
185 "Could not resolve the remote IP or hostname");
186 ke->client_entry->ke = NULL;
187 ke->completion(ke->client, ke->conn, ke->client_entry,
188 SILC_KEY_AGREEMENT_ERROR, NULL, ke->context);
189 silc_schedule_task_del_by_fd(client->schedule, ke->fd);
190 silc_schedule_unset_listen_fd(ke->client->schedule, ke->fd);
191 silc_net_close_connection(ke->fd);
193 silc_schedule_task_del(client->schedule, ke->timeout);
197 if (!newsocket->hostname)
198 newsocket->hostname = strdup(newsocket->ip);
199 newsocket->port = silc_net_get_remote_port(sock);
200 silc_client_add_socket(client, newsocket);
202 /* Allocate internal context for key exchange protocol. This is
203 sent as context for the protocol. */
204 proto_ctx = silc_calloc(1, sizeof(*proto_ctx));
205 proto_ctx->client = client;
206 proto_ctx->sock = silc_socket_dup(newsocket);
207 proto_ctx->rng = client->rng;
208 proto_ctx->responder = TRUE;
209 proto_ctx->context = context;
210 proto_ctx->send_packet = silc_client_key_agreement_send_packet;
211 proto_ctx->verify = silc_client_protocol_ke_verify_key;
212 ke->proto_ctx = proto_ctx;
214 /* Prepare the connection for key exchange protocol. We allocate the
215 protocol but will not start it yet. The connector will be the
216 initiator of the protocol thus we will wait for initiation from
217 there before we start the protocol. */
218 silc_protocol_alloc(SILC_PROTOCOL_CLIENT_KEY_EXCHANGE,
219 &newsocket->protocol, proto_ctx,
220 silc_client_key_agreement_final);
222 /* Register the connection for network input and output. This sets
223 that scheduler will listen for incoming packets for this connection
224 and sets that outgoing packets may be sent to this connection as well.
225 However, this doesn't set the scheduler for outgoing traffic, it
226 will be set separately by calling SILC_CLIENT_SET_CONNECTION_FOR_OUTPUT,
227 later when outgoing data is available. */
228 context = (void *)client;
229 SILC_CLIENT_REGISTER_CONNECTION_FOR_IO(sock);
232 /* Timeout occured during key agreement. This means that the key agreement
233 protocol was not completed in the specified timeout. We will call the
234 completion callback. */
236 SILC_TASK_CALLBACK(silc_client_key_agreement_timeout)
238 SilcClientKeyAgreement ke = (SilcClientKeyAgreement)context;
240 ke->client_entry->ke = NULL;
241 ke->completion(ke->client, ke->conn, ke->client_entry,
242 SILC_KEY_AGREEMENT_TIMEOUT, NULL, ke->context);
245 silc_client_del_socket(ke->client, ke->sock);
246 silc_socket_free(ke->sock);
248 if (ke->proto_ctx && ke->proto_ctx->ske)
249 silc_ske_free(ke->proto_ctx->ske);
250 ke->client_entry->ke = NULL;
252 silc_schedule_task_del_by_fd(ke->client->schedule, ke->fd);
253 silc_schedule_unset_listen_fd(ke->client->schedule, ke->fd);
254 silc_net_close_connection(ke->fd);
258 /* Sends key agreement request to the remote client indicated by the
259 `client_entry'. If the caller provides the `hostname' and the `port'
260 arguments then the library will bind the client to that hostname and
261 that port for the key agreement protocol. It also sends the `hostname'
262 and the `port' in the key agreement packet to the remote client. This
263 would indicate that the remote client may initiate the key agreement
264 protocol to the `hostname' on the `port'. If port is zero then the
265 bound port is undefined (the operating system defines it).
267 If the `hostname' and `port' is not provided then empty key agreement
268 packet is sent to the remote client. The remote client may reply with
269 the same packet including its hostname and port. If the library receives
270 the reply from the remote client the `key_agreement' client operation
271 callback will be called to verify whether the user wants to perform the
272 key agreement or not.
274 NOTE: If the application provided the `hostname' and the `port' and the
275 remote side initiates the key agreement protocol it is not verified
276 from the user anymore whether the protocol should be executed or not.
277 By setting the `hostname' and `port' the user gives permission to
278 perform the protocol (we are responder in this case).
280 NOTE: If the remote side decides not to initiate the key agreement
281 or decides not to reply with the key agreement packet then we cannot
282 perform the key agreement at all. If the key agreement protocol is
283 performed the `completion' callback with the `context' will be called.
284 If remote side decides to ignore the request the `completion' will be
285 called after the specified timeout, `timeout_secs'.
287 NOTE: If the `hostname' and the `port' was not provided the `completion'
288 will not be called at all since this does nothing more than sending
289 a packet to the remote host.
291 NOTE: There can be only one active key agreement for one client entry.
292 Before setting new one, the old one must be finished (it is finished
293 after calling the completion callback) or the function
294 silc_client_abort_key_agreement must be called. */
296 void silc_client_send_key_agreement(SilcClient client,
297 SilcClientConnection conn,
298 SilcClientEntry client_entry,
299 const char *hostname,
300 const char *bindhost,
302 SilcUInt32 timeout_secs,
303 SilcKeyAgreementCallback completion,
306 SilcSocketConnection sock = conn->sock;
307 SilcClientKeyAgreement ke = NULL;
310 if (!client_entry || client_entry->ke)
313 /* Create the listener if hostname and port was provided.
314 * also, use bindhost if it was specified.
318 ke = silc_calloc(1, sizeof(*ke));
321 ke->fd = silc_net_create_server(port, bindhost);
323 ke->fd = silc_net_create_server(port, hostname);
326 client->internal->ops->say(
327 client, conn, SILC_CLIENT_MESSAGE_ERROR,
328 "Cannot create listener on %s on port %d: %s",
329 (bindhost) ? bindhost:hostname, port, strerror(errno));
330 completion(client, conn, client_entry, SILC_KEY_AGREEMENT_FAILURE,
339 ke->client_entry = client_entry;
340 ke->completion = completion;
341 ke->context = context;
343 /* Add listener task to the scheduler. This task receives the key
345 silc_schedule_task_add(client->schedule, ke->fd,
346 silc_client_process_key_agreement,
349 SILC_TASK_PRI_NORMAL);
351 /* Register a timeout task that will be executed if the connector
352 will not start the key exchange protocol within the specified
354 ke->timeout = silc_schedule_task_add(client->schedule, 0,
355 silc_client_key_agreement_timeout,
356 (void *)ke, timeout_secs, 0,
357 SILC_TASK_TIMEOUT, SILC_TASK_PRI_LOW);
360 /* Encode the key agreement payload */
361 buffer = silc_key_agreement_payload_encode(hostname,
363 silc_net_get_local_port(ke->fd));
365 /* Send the key agreement packet to the client */
366 silc_client_packet_send(client, sock, SILC_PACKET_KEY_AGREEMENT,
367 client_entry->id, SILC_ID_CLIENT, NULL, NULL,
368 buffer->data, buffer->len, FALSE);
369 silc_buffer_free(buffer);
374 silc_client_connect_to_client_internal(SilcClientInternalConnectContext *ctx)
378 /* Create connection to server asynchronously */
379 sock = silc_net_create_connection_async(NULL, ctx->port, ctx->host);
383 /* Register task that will receive the async connect and will
385 ctx->task = silc_schedule_task_add(ctx->client->schedule, sock,
386 silc_client_perform_key_agreement_start,
389 SILC_TASK_PRI_NORMAL);
390 silc_schedule_set_listen_fd(ctx->client->schedule, sock, SILC_TASK_WRITE);
397 /* Routine used by silc_client_perform_key_agreement to create connection
398 to the remote client on specified port. */
401 silc_client_connect_to_client(SilcClient client,
402 SilcClientConnection conn, int port,
403 char *host, void *context)
405 SilcClientInternalConnectContext *ctx;
407 /* Allocate internal context for connection process. This is
408 needed as we are doing async connecting. */
409 ctx = silc_calloc(1, sizeof(*ctx));
410 ctx->client = client;
412 ctx->host = strdup(host);
415 ctx->context = context;
417 /* Do the actual connecting process */
418 return silc_client_connect_to_client_internal(ctx);
421 /* Callback that is called after connection has been created. This actually
422 starts the key agreement protocol. This is initiator function. */
424 SILC_TASK_CALLBACK(silc_client_perform_key_agreement_start)
426 SilcClientInternalConnectContext *ctx =
427 (SilcClientInternalConnectContext *)context;
428 SilcClient client = ctx->client;
429 SilcClientConnection conn = ctx->conn;
430 SilcClientKeyAgreement ke = (SilcClientKeyAgreement)ctx->context;
431 int opt, opt_len = sizeof(opt);
433 SILC_LOG_DEBUG(("Start"));
435 /* Check the socket status as it might be in error */
436 silc_net_get_socket_opt(fd, SOL_SOCKET, SO_ERROR, &opt, &opt_len);
438 if (ctx->tries < 2) {
439 /* Connection failed but lets try again */
440 client->internal->ops->say(client, conn, SILC_CLIENT_MESSAGE_ERROR,
441 "Could not connect to client %s: %s",
442 ctx->host, strerror(opt));
443 client->internal->ops->say(client, conn, SILC_CLIENT_MESSAGE_AUDIT,
444 "Connecting to port %d of client %s resumed",
445 ctx->port, ctx->host);
447 /* Unregister old connection try */
448 silc_schedule_unset_listen_fd(client->schedule, fd);
449 silc_net_close_connection(fd);
450 silc_schedule_task_del(client->schedule, ctx->task);
453 silc_client_connect_to_client_internal(ctx);
456 /* Connection failed and we won't try anymore */
457 client->internal->ops->say(client, conn, SILC_CLIENT_MESSAGE_ERROR,
458 "Could not connect to client %s: %s",
459 ctx->host, strerror(opt));
460 silc_schedule_unset_listen_fd(client->schedule, fd);
461 silc_net_close_connection(fd);
462 silc_schedule_task_del(client->schedule, ctx->task);
463 silc_free(ctx->host);
466 /* Call the completion callback */
467 ke->completion(ke->client, ke->conn, ke->client_entry,
468 SILC_KEY_AGREEMENT_FAILURE, NULL, ke->context);
474 silc_schedule_unset_listen_fd(client->schedule, fd);
475 silc_schedule_task_del(client->schedule, ctx->task);
479 /* Now actually perform the key agreement protocol */
480 silc_client_perform_key_agreement_fd(ke->client, ke->conn,
481 ke->client_entry, ke->fd, ctx->host,
482 ke->completion, ke->context);
484 silc_free(ctx->host);
488 /* Performs the actual key agreement protocol. Application may use this
489 to initiate the key agreement protocol. This can be called for example
490 after the application has received the `key_agreement' client operation,
491 and did not return TRUE from it.
493 The `hostname' is the remote hostname (or IP address) and the `port'
494 is the remote port. The `completion' callback with the `context' will
495 be called after the key agreement protocol.
497 NOTE: If the application returns TRUE in the `key_agreement' client
498 operation the library will automatically start the key agreement. In this
499 case the application must not call this function. However, application
500 may choose to just ignore the `key_agreement' client operation (and
501 merely just print information about it on the screen) and call this
502 function when the user whishes to do so (by, for example, giving some
503 specific command). Thus, the API provides both, automatic and manual
504 initiation of the key agreement. Calling this function is the manual
505 initiation and returning TRUE in the `key_agreement' client operation
506 is the automatic initiation. */
508 void silc_client_perform_key_agreement(SilcClient client,
509 SilcClientConnection conn,
510 SilcClientEntry client_entry,
513 SilcKeyAgreementCallback completion,
516 SilcClientKeyAgreement ke;
518 SILC_LOG_DEBUG(("Start"));
520 if (!client_entry || !hostname || !port)
523 ke = silc_calloc(1, sizeof(*ke));
526 ke->client_entry = client_entry;
527 ke->completion = completion;
528 ke->context = context;
530 /* Connect to the remote client */
531 ke->fd = silc_client_connect_to_client(client, conn, port, hostname, ke);
533 completion(client, conn, client_entry, SILC_KEY_AGREEMENT_FAILURE,
540 /* Same as above but application has created already the connection to
541 the remote host. The `sock' is the socket to the remote connection.
542 Application can use this function if it does not want the client library
543 to create the connection. */
545 void silc_client_perform_key_agreement_fd(SilcClient client,
546 SilcClientConnection conn,
547 SilcClientEntry client_entry,
550 SilcKeyAgreementCallback completion,
553 SilcClientKeyAgreement ke;
554 SilcClientKEInternalContext *proto_ctx;
555 SilcProtocol protocol;
557 SILC_LOG_DEBUG(("Start"));
562 ke = silc_calloc(1, sizeof(*ke));
565 ke->client_entry = client_entry;
567 ke->completion = completion;
568 ke->context = context;
570 /* Allocate new socket connection object */
571 silc_socket_alloc(sock, SILC_SOCKET_TYPE_UNKNOWN, (void *)conn, &ke->sock);
572 silc_client_add_socket(client, ke->sock);
573 ke->sock->hostname = strdup(hostname);
574 ke->sock->port = silc_net_get_remote_port(sock);
576 /* Allocate internal context for key exchange protocol. This is
577 sent as context for the protocol. */
578 proto_ctx = silc_calloc(1, sizeof(*proto_ctx));
579 proto_ctx->client = client;
580 proto_ctx->sock = silc_socket_dup(ke->sock);
581 proto_ctx->rng = client->rng;
582 proto_ctx->responder = FALSE;
583 proto_ctx->context = ke;
584 proto_ctx->send_packet = silc_client_key_agreement_send_packet;
585 proto_ctx->verify = silc_client_protocol_ke_verify_key;
586 ke->proto_ctx = proto_ctx;
588 /* Perform key exchange protocol. */
589 silc_protocol_alloc(SILC_PROTOCOL_CLIENT_KEY_EXCHANGE,
590 &protocol, (void *)proto_ctx,
591 silc_client_key_agreement_final);
592 ke->sock->protocol = protocol;
594 /* Register the connection for network input and output. This sets
595 that scheduler will listen for incoming packets for this connection
596 and sets that outgoing packets may be sent to this connection as well.
597 However, this doesn't set the scheduler for outgoing traffic, it will
598 be set separately by calling SILC_CLIENT_SET_CONNECTION_FOR_OUTPUT,
599 later when outgoing data is available. */
600 context = (void *)client;
601 SILC_CLIENT_REGISTER_CONNECTION_FOR_IO(sock);
603 /* Execute the protocol */
604 silc_protocol_execute(protocol, client->schedule, 0, 0);
607 /* This function can be called to unbind the hostname and the port for
608 the key agreement protocol. However, this function has effect only
609 before the key agreement protocol has been performed. After it has
610 been performed the library will automatically unbind the port. The
611 `client_entry' is the client to which we sent the key agreement
614 void silc_client_abort_key_agreement(SilcClient client,
615 SilcClientConnection conn,
616 SilcClientEntry client_entry)
621 if (client_entry->ke) {
622 SilcClientKeyAgreement ke;
624 if (client_entry->ke->sock) {
625 silc_client_del_socket(client_entry->ke->client, client_entry->ke->sock);
626 silc_socket_free(client_entry->ke->sock);
628 silc_schedule_task_del_by_fd(client->schedule, client_entry->ke->fd);
629 if (client_entry->ke->timeout)
630 silc_schedule_task_del(client->schedule,
631 client_entry->ke->timeout);
632 ke = client_entry->ke;
633 client_entry->ke = NULL;
634 ke->completion(client, conn, client_entry,
635 SILC_KEY_AGREEMENT_ABORTED, NULL, ke->context);
640 /* Callback function that is called after we've resolved the client
641 information who sent us the key agreement packet from the server.
642 We actually call the key_agreement client operation now. */
645 silc_client_key_agreement_resolve_cb(SilcClient client,
646 SilcClientConnection conn,
647 SilcClientEntry *clients,
648 SilcUInt32 clients_count,
651 SilcPacketContext *packet = (SilcPacketContext *)context;
652 SilcKeyAgreementPayload payload;
654 SilcKeyAgreementCallback completion;
655 void *completion_context;
660 /* Parse the key agreement payload */
661 payload = silc_key_agreement_payload_parse(packet->buffer->data,
662 packet->buffer->len);
666 /* Call the key_agreement client operation */
667 ret = client->internal->ops->key_agreement(
668 client, conn, clients[0],
669 silc_key_agreement_get_hostname(payload),
670 silc_key_agreement_get_port(payload),
671 &completion, &completion_context);
673 /* If the user returned TRUE then we'll start the key agreement right
674 here and right now. */
676 silc_client_perform_key_agreement(client, conn, clients[0],
677 silc_key_agreement_get_hostname(payload),
678 silc_key_agreement_get_port(payload),
679 completion, completion_context);
681 silc_key_agreement_payload_free(payload);
684 silc_packet_context_free(packet);
687 /* Received Key Agreement packet from remote client. Process the packet
688 and resolve the client information from the server before actually
689 letting the application know that we've received this packet. Then
690 call the key_agreement client operation and let the user decide
691 whether we perform the key agreement protocol now or not. */
693 void silc_client_key_agreement(SilcClient client,
694 SilcSocketConnection sock,
695 SilcPacketContext *packet)
697 SilcClientID *remote_id;
699 if (packet->src_id_type != SILC_ID_CLIENT)
702 remote_id = silc_id_str2id(packet->src_id, packet->src_id_len,
707 silc_client_get_client_by_id_resolve(client, sock->user_data, remote_id,
708 silc_client_key_agreement_resolve_cb,
709 silc_packet_context_dup(packet));
710 silc_free(remote_id);