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.
23 #include "splay_tree.h"
25 #include "connection.h"
37 static bool mykeyused = false;
39 void send_key_changed(void) {
43 send_request(everyone, "%d %x %s", KEY_CHANGED, rand(), myself->name);
45 /* Immediately send new keys to directly connected nodes to keep UDP mappings alive */
47 for(node = connection_tree->head; node; node = node->next) {
49 if(c->status.active && c->node && c->node->status.reachable) {
50 if(!c->node->status.sptps)
51 send_ans_key(c->node);
55 /* Force key exchange for connections using SPTPS */
58 for(node = node_tree->head; node; node = node->next) {
59 node_t *n = node->data;
60 if(n->status.reachable && n->status.validkey && n->status.sptps)
61 sptps_force_kex(&n->sptps);
66 bool key_changed_h(connection_t *c, const char *request) {
67 char name[MAX_STRING_SIZE];
70 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
71 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
72 c->name, c->hostname);
76 if(seen_request(request))
79 n = lookup_node(name);
82 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
83 "KEY_CHANGED", c->name, c->hostname, name);
87 if(!n->status.sptps) {
88 n->status.validkey = false;
95 forward_request(c, request);
100 static bool send_initial_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
102 to->sptps.send_data = send_sptps_data;
103 char buf[len * 4 / 3 + 5];
104 b64encode(data, buf, len);
105 return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_KEY, buf);
108 bool send_req_key(node_t *to) {
109 if(to->status.sptps) {
110 if(!node_read_ecdsa_public_key(to)) {
111 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No ECDSA key known for %s (%s)", to->name, to->hostname);
112 send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, REQ_PUBKEY);
115 char label[25 + strlen(myself->name) + strlen(to->name)];
116 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", myself->name, to->name);
117 sptps_stop(&to->sptps);
118 to->status.validkey = false;
119 to->incompression = myself->incompression;
120 return sptps_start(&to->sptps, to, true, true, myself->connection->ecdsa, to->ecdsa, label, sizeof label, send_initial_sptps_data, receive_sptps_record);
123 return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
126 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
128 static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, int reqno) {
131 char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
132 send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
138 if(node_read_ecdsa_public_key(from)) {
139 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
143 char pubkey[MAX_STRING_SIZE];
144 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !ecdsa_set_base64_public_key(&from->ecdsa, pubkey)) {
145 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
149 logger(DEBUG_PROTOCOL, LOG_INFO, "Learned ECDSA public key from %s (%s)", from->name, from->hostname);
150 append_config_file(from->name, "ECDSAPublicKey", pubkey);
155 if(!node_read_ecdsa_public_key(from)) {
156 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No ECDSA key known for %s (%s)", from->name, from->hostname);
157 send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
163 char buf[MAX_STRING_SIZE];
164 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1) {
165 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", from->name, from->hostname, "invalid SPTPS data");
168 int len = b64decode(buf, buf, strlen(buf));
171 char label[25 + strlen(from->name) + strlen(myself->name)];
172 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name);
173 sptps_stop(&from->sptps);
174 from->status.validkey = false;
175 sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data, receive_sptps_record);
176 sptps_receive_data(&from->sptps, buf, len);
181 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
186 bool req_key_h(connection_t *c, const char *request) {
187 char from_name[MAX_STRING_SIZE];
188 char to_name[MAX_STRING_SIZE];
192 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
193 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
198 if(!check_id(from_name) || !check_id(to_name)) {
199 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
203 from = lookup_node(from_name);
206 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
207 "REQ_KEY", c->name, c->hostname, from_name);
211 to = lookup_node(to_name);
214 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
215 "REQ_KEY", c->name, c->hostname, to_name);
219 /* Check if this key request is for us */
221 if(to == myself) { /* Yes */
222 /* Is this an extended REQ_KEY message? */
223 if(experimental && reqno)
224 return req_key_ext_h(c, request, from, reqno);
226 /* No, just send our key back */
232 if(!to->status.reachable) {
233 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
234 "REQ_KEY", c->name, c->hostname, to_name);
238 send_request(to->nexthop->connection, "%s", request);
244 bool send_ans_key(node_t *to) {
248 size_t keylen = cipher_keylength(&myself->incipher);
249 char key[keylen * 2 + 1];
251 cipher_open_by_nid(&to->incipher, cipher_get_nid(&myself->incipher));
252 digest_open_by_nid(&to->indigest, digest_get_nid(&myself->indigest), digest_length(&myself->indigest));
253 to->incompression = myself->incompression;
255 randomize(key, keylen);
256 cipher_set_key(&to->incipher, key, false);
257 digest_set_key(&to->indigest, key, keylen);
259 bin2hex(key, key, keylen);
261 // Reset sequence number and late packet window
263 to->received_seqno = 0;
264 if(replaywin) memset(to->late, 0, replaywin);
266 return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
267 myself->name, to->name, key,
268 cipher_get_nid(&to->incipher),
269 digest_get_nid(&to->indigest),
270 (int)digest_length(&to->indigest),
274 bool ans_key_h(connection_t *c, const char *request) {
275 char from_name[MAX_STRING_SIZE];
276 char to_name[MAX_STRING_SIZE];
277 char key[MAX_STRING_SIZE];
278 char address[MAX_STRING_SIZE] = "";
279 char port[MAX_STRING_SIZE] = "";
280 int cipher, digest, maclength, compression, keylen;
283 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
284 from_name, to_name, key, &cipher, &digest, &maclength,
285 &compression, address, port) < 7) {
286 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
291 if(!check_id(from_name) || !check_id(to_name)) {
292 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
296 from = lookup_node(from_name);
299 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
300 "ANS_KEY", c->name, c->hostname, from_name);
304 to = lookup_node(to_name);
307 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
308 "ANS_KEY", c->name, c->hostname, to_name);
312 /* Forward it if necessary */
318 if(!to->status.reachable) {
319 logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
320 "ANS_KEY", c->name, c->hostname, to_name);
324 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
325 char *address, *port;
326 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
327 sockaddr2str(&from->address, &address, &port);
328 send_request(to->nexthop->connection, "%s %s %s", request, address, port);
334 return send_request(to->nexthop->connection, "%s", request);
337 /* Don't use key material until every check has passed. */
338 from->status.validkey = false;
340 if(compression < 0 || compression > 11) {
341 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
345 from->outcompression = compression;
347 /* SPTPS or old-style key exchange? */
349 if(from->status.sptps) {
350 char buf[strlen(key)];
351 int len = b64decode(key, buf, strlen(key));
353 if(!sptps_receive_data(&from->sptps, buf, len))
354 logger(DEBUG_ALWAYS, LOG_ERR, "Error processing SPTPS data from %s (%s)", from->name, from->hostname);
356 if(from->status.validkey) {
357 if(*address && *port) {
358 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
359 sockaddr_t sa = str2sockaddr(address, port);
360 update_node_udp(from, &sa);
363 if(from->options & OPTION_PMTU_DISCOVERY)
364 send_mtu_probe(from);
370 /* Check and lookup cipher and digest algorithms */
372 if(!cipher_open_by_nid(&from->outcipher, cipher)) {
373 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
377 if(!digest_open_by_nid(&from->outdigest, digest, maclength)) {
378 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
382 if(maclength != digest_length(&from->outdigest)) {
383 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
389 keylen = hex2bin(key, key, sizeof key);
391 if(keylen != cipher_keylength(&from->outcipher)) {
392 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
396 /* Update our copy of the origin's packet key */
398 cipher_set_key(&from->outcipher, key, true);
399 digest_set_key(&from->outdigest, key, keylen);
401 from->status.validkey = true;
402 from->sent_seqno = 0;
404 if(*address && *port) {
405 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
406 sockaddr_t sa = str2sockaddr(address, port);
407 update_node_udp(from, &sa);
410 if(from->options & OPTION_PMTU_DISCOVERY)
411 send_mtu_probe(from);