2 protocol_key.c -- handle the meta-protocol, key exchange
3 Copyright (C) 1999-2005 Ivo Timmermans,
4 2000-2012 Guus Sliepen <guus@tinc-vpn.org>
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License along
17 with this program; if not, write to the Free Software Foundation, Inc.,
18 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
24 #include "connection.h"
36 static bool mykeyused = false;
38 void send_key_changed(void) {
39 send_request(everyone, "%d %x %s", KEY_CHANGED, rand(), myself->name);
41 /* Immediately send new keys to directly connected nodes to keep UDP mappings alive */
43 for(list_node_t *node = connection_list->head, *next; node; node = next) {
45 connection_t *c = node->data;
46 if(c->status.active && c->node && c->node->status.reachable) {
47 if(!c->node->status.sptps)
48 send_ans_key(c->node);
52 /* Force key exchange for connections using SPTPS */
55 for(splay_node_t *node = node_tree->head; node; node = node->next) {
56 node_t *n = node->data;
57 if(n->status.reachable && n->status.validkey && n->status.sptps)
58 sptps_force_kex(&n->sptps);
63 bool key_changed_h(connection_t *c, const char *request) {
64 char name[MAX_STRING_SIZE];
67 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
68 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
69 c->name, c->hostname);
73 if(seen_request(request))
76 n = lookup_node(name);
79 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
80 "KEY_CHANGED", c->name, c->hostname, name);
84 if(!n->status.sptps) {
85 n->status.validkey = false;
92 forward_request(c, request);
97 static bool send_initial_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
99 to->sptps.send_data = send_sptps_data;
100 char buf[len * 4 / 3 + 5];
101 b64encode(data, buf, len);
102 return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_KEY, buf);
105 bool send_req_key(node_t *to) {
106 if(to->status.sptps) {
107 if(!node_read_ecdsa_public_key(to)) {
108 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No ECDSA key known for %s (%s)", to->name, to->hostname);
109 send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, REQ_PUBKEY);
112 char label[25 + strlen(myself->name) + strlen(to->name)];
113 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", myself->name, to->name);
114 sptps_stop(&to->sptps);
115 to->status.validkey = false;
116 to->status.waitingforkey = true;
117 to->last_req_key = time(NULL);
118 to->incompression = myself->incompression;
119 return sptps_start(&to->sptps, to, true, true, myself->connection->ecdsa, to->ecdsa, label, sizeof label, send_initial_sptps_data, receive_sptps_record);
122 return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
125 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
127 static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, int reqno) {
130 char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
131 send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
137 if(node_read_ecdsa_public_key(from)) {
138 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
142 char pubkey[MAX_STRING_SIZE];
143 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !ecdsa_set_base64_public_key(&from->ecdsa, pubkey)) {
144 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
148 logger(DEBUG_PROTOCOL, LOG_INFO, "Learned ECDSA public key from %s (%s)", from->name, from->hostname);
149 append_config_file(from->name, "ECDSAPublicKey", pubkey);
154 if(!node_read_ecdsa_public_key(from)) {
155 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No ECDSA key known for %s (%s)", from->name, from->hostname);
156 send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
162 char buf[MAX_STRING_SIZE];
163 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1) {
164 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", from->name, from->hostname, "invalid SPTPS data");
167 int len = b64decode(buf, buf, strlen(buf));
170 char label[25 + strlen(from->name) + strlen(myself->name)];
171 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name);
172 sptps_stop(&from->sptps);
173 from->status.validkey = false;
174 from->status.waitingforkey = true;
175 from->last_req_key = time(NULL);
176 sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data, receive_sptps_record);
177 sptps_receive_data(&from->sptps, buf, len);
182 if(!from->status.validkey) {
183 logger(DEBUG_PROTOCOL, LOG_ERR, "Got REQ_PACKET from %s (%s) but we don't have a valid key yet", from->name, from->hostname);
187 char buf[MAX_STRING_SIZE];
188 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1) {
189 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", from->name, from->hostname, "invalid SPTPS data");
192 int len = b64decode(buf, buf, strlen(buf));
193 sptps_receive_data(&from->sptps, buf, len);
198 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
203 bool req_key_h(connection_t *c, const char *request) {
204 char from_name[MAX_STRING_SIZE];
205 char to_name[MAX_STRING_SIZE];
209 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
210 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
215 if(!check_id(from_name) || !check_id(to_name)) {
216 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
220 from = lookup_node(from_name);
223 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
224 "REQ_KEY", c->name, c->hostname, from_name);
228 to = lookup_node(to_name);
231 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
232 "REQ_KEY", c->name, c->hostname, to_name);
236 /* Check if this key request is for us */
238 if(to == myself) { /* Yes */
239 /* Is this an extended REQ_KEY message? */
240 if(experimental && reqno)
241 return req_key_ext_h(c, request, from, reqno);
243 /* No, just send our key back */
249 if(!to->status.reachable) {
250 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
251 "REQ_KEY", c->name, c->hostname, to_name);
255 send_request(to->nexthop->connection, "%s", request);
261 bool send_ans_key(node_t *to) {
265 size_t keylen = cipher_keylength(&myself->incipher);
266 char key[keylen * 2 + 1];
268 cipher_open_by_nid(&to->incipher, cipher_get_nid(&myself->incipher));
269 digest_open_by_nid(&to->indigest, digest_get_nid(&myself->indigest), digest_length(&myself->indigest));
270 to->incompression = myself->incompression;
272 randomize(key, keylen);
273 cipher_set_key(&to->incipher, key, false);
274 digest_set_key(&to->indigest, key, keylen);
276 bin2hex(key, key, keylen);
278 // Reset sequence number and late packet window
280 to->received_seqno = 0;
281 if(replaywin) memset(to->late, 0, replaywin);
283 return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
284 myself->name, to->name, key,
285 cipher_get_nid(&to->incipher),
286 digest_get_nid(&to->indigest),
287 (int)digest_length(&to->indigest),
291 bool ans_key_h(connection_t *c, const char *request) {
292 char from_name[MAX_STRING_SIZE];
293 char to_name[MAX_STRING_SIZE];
294 char key[MAX_STRING_SIZE];
295 char address[MAX_STRING_SIZE] = "";
296 char port[MAX_STRING_SIZE] = "";
297 int cipher, digest, maclength, compression, keylen;
300 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
301 from_name, to_name, key, &cipher, &digest, &maclength,
302 &compression, address, port) < 7) {
303 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
308 if(!check_id(from_name) || !check_id(to_name)) {
309 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
313 from = lookup_node(from_name);
316 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
317 "ANS_KEY", c->name, c->hostname, from_name);
321 to = lookup_node(to_name);
324 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
325 "ANS_KEY", c->name, c->hostname, to_name);
329 /* Forward it if necessary */
335 if(!to->status.reachable) {
336 logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
337 "ANS_KEY", c->name, c->hostname, to_name);
341 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
342 char *address, *port;
343 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
344 sockaddr2str(&from->address, &address, &port);
345 send_request(to->nexthop->connection, "%s %s %s", request, address, port);
351 return send_request(to->nexthop->connection, "%s", request);
354 /* Don't use key material until every check has passed. */
355 from->status.validkey = false;
357 if(compression < 0 || compression > 11) {
358 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
362 from->outcompression = compression;
364 /* SPTPS or old-style key exchange? */
366 if(from->status.sptps) {
367 char buf[strlen(key)];
368 int len = b64decode(key, buf, strlen(key));
370 if(!sptps_receive_data(&from->sptps, buf, len))
371 logger(DEBUG_ALWAYS, LOG_ERR, "Error processing SPTPS data from %s (%s)", from->name, from->hostname);
373 if(from->status.validkey) {
374 if(*address && *port) {
375 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
376 sockaddr_t sa = str2sockaddr(address, port);
377 update_node_udp(from, &sa);
380 if(from->options & OPTION_PMTU_DISCOVERY)
381 send_mtu_probe(from);
387 /* Check and lookup cipher and digest algorithms */
389 if(!cipher_open_by_nid(&from->outcipher, cipher)) {
390 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
394 if(!digest_open_by_nid(&from->outdigest, digest, maclength)) {
395 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
399 if(maclength != digest_length(&from->outdigest)) {
400 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
406 keylen = hex2bin(key, key, sizeof key);
408 if(keylen != cipher_keylength(&from->outcipher)) {
409 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
413 /* Update our copy of the origin's packet key */
415 cipher_set_key(&from->outcipher, key, true);
416 digest_set_key(&from->outdigest, key, keylen);
418 from->status.validkey = true;
419 from->sent_seqno = 0;
421 if(*address && *port) {
422 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
423 sockaddr_t sa = str2sockaddr(address, port);
424 update_node_udp(from, &sa);
427 if(from->options & OPTION_PMTU_DISCOVERY)
428 send_mtu_probe(from);