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_each(connection_t, c, connection_list)
44 if(c->status.active && c->node && c->node->status.reachable && !c->node->status.sptps)
45 send_ans_key(c->node);
47 /* Force key exchange for connections using SPTPS */
50 for splay_each(node_t, n, node_tree)
51 if(n->status.reachable && n->status.validkey && n->status.sptps)
52 sptps_force_kex(&n->sptps);
56 bool key_changed_h(connection_t *c, const char *request) {
57 char name[MAX_STRING_SIZE];
60 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
61 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
62 c->name, c->hostname);
66 if(seen_request(request))
69 n = lookup_node(name);
72 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
73 "KEY_CHANGED", c->name, c->hostname, name);
77 if(!n->status.sptps) {
78 n->status.validkey = false;
85 forward_request(c, request);
90 static bool send_initial_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
92 to->sptps.send_data = send_sptps_data;
93 char buf[len * 4 / 3 + 5];
94 b64encode(data, buf, len);
95 return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_KEY, buf);
98 bool send_req_key(node_t *to) {
99 if(to->status.sptps) {
100 if(!node_read_ecdsa_public_key(to)) {
101 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No ECDSA key known for %s (%s)", to->name, to->hostname);
102 send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, REQ_PUBKEY);
105 char label[25 + strlen(myself->name) + strlen(to->name)];
106 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", myself->name, to->name);
107 sptps_stop(&to->sptps);
108 to->status.validkey = false;
109 to->status.waitingforkey = true;
110 to->last_req_key = time(NULL);
111 to->incompression = myself->incompression;
112 return sptps_start(&to->sptps, to, true, true, myself->connection->ecdsa, to->ecdsa, label, sizeof label, send_initial_sptps_data, receive_sptps_record);
115 return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
118 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
120 static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, int reqno) {
123 char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
124 send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
130 if(node_read_ecdsa_public_key(from)) {
131 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
135 char pubkey[MAX_STRING_SIZE];
136 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !ecdsa_set_base64_public_key(&from->ecdsa, pubkey)) {
137 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
141 logger(DEBUG_PROTOCOL, LOG_INFO, "Learned ECDSA public key from %s (%s)", from->name, from->hostname);
142 append_config_file(from->name, "ECDSAPublicKey", pubkey);
147 if(!node_read_ecdsa_public_key(from)) {
148 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No ECDSA key known for %s (%s)", from->name, from->hostname);
149 send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
155 char buf[MAX_STRING_SIZE];
156 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1) {
157 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", from->name, from->hostname, "invalid SPTPS data");
160 int len = b64decode(buf, buf, strlen(buf));
163 char label[25 + strlen(from->name) + strlen(myself->name)];
164 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name);
165 sptps_stop(&from->sptps);
166 from->status.validkey = false;
167 from->status.waitingforkey = true;
168 from->last_req_key = time(NULL);
169 sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data, receive_sptps_record);
170 sptps_receive_data(&from->sptps, buf, len);
175 if(!from->status.validkey) {
176 logger(DEBUG_PROTOCOL, LOG_ERR, "Got REQ_PACKET from %s (%s) but we don't have a valid key yet", from->name, from->hostname);
180 char buf[MAX_STRING_SIZE];
181 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1) {
182 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", from->name, from->hostname, "invalid SPTPS data");
185 int len = b64decode(buf, buf, strlen(buf));
186 sptps_receive_data(&from->sptps, buf, len);
191 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
196 bool req_key_h(connection_t *c, const char *request) {
197 char from_name[MAX_STRING_SIZE];
198 char to_name[MAX_STRING_SIZE];
202 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
203 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
208 if(!check_id(from_name) || !check_id(to_name)) {
209 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
213 from = lookup_node(from_name);
216 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
217 "REQ_KEY", c->name, c->hostname, from_name);
221 to = lookup_node(to_name);
224 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
225 "REQ_KEY", c->name, c->hostname, to_name);
229 /* Check if this key request is for us */
231 if(to == myself) { /* Yes */
232 /* Is this an extended REQ_KEY message? */
233 if(experimental && reqno)
234 return req_key_ext_h(c, request, from, reqno);
236 /* No, just send our key back */
242 if(!to->status.reachable) {
243 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
244 "REQ_KEY", c->name, c->hostname, to_name);
248 send_request(to->nexthop->connection, "%s", request);
254 bool send_ans_key(node_t *to) {
258 size_t keylen = cipher_keylength(&myself->incipher);
259 char key[keylen * 2 + 1];
261 cipher_close(&to->incipher);
262 digest_close(&to->indigest);
264 cipher_open_by_nid(&to->incipher, cipher_get_nid(&myself->incipher));
265 digest_open_by_nid(&to->indigest, digest_get_nid(&myself->indigest), digest_length(&myself->indigest));
266 to->incompression = myself->incompression;
268 randomize(key, keylen);
269 cipher_set_key(&to->incipher, key, false);
270 digest_set_key(&to->indigest, key, keylen);
272 bin2hex(key, key, keylen);
274 // Reset sequence number and late packet window
276 to->received_seqno = 0;
277 if(replaywin) memset(to->late, 0, replaywin);
279 return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
280 myself->name, to->name, key,
281 cipher_get_nid(&to->incipher),
282 digest_get_nid(&to->indigest),
283 (int)digest_length(&to->indigest),
287 bool ans_key_h(connection_t *c, const char *request) {
288 char from_name[MAX_STRING_SIZE];
289 char to_name[MAX_STRING_SIZE];
290 char key[MAX_STRING_SIZE];
291 char address[MAX_STRING_SIZE] = "";
292 char port[MAX_STRING_SIZE] = "";
293 int cipher, digest, maclength, compression, keylen;
296 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
297 from_name, to_name, key, &cipher, &digest, &maclength,
298 &compression, address, port) < 7) {
299 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
304 if(!check_id(from_name) || !check_id(to_name)) {
305 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
309 from = lookup_node(from_name);
312 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
313 "ANS_KEY", c->name, c->hostname, from_name);
317 to = lookup_node(to_name);
320 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
321 "ANS_KEY", c->name, c->hostname, to_name);
325 /* Forward it if necessary */
331 if(!to->status.reachable) {
332 logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
333 "ANS_KEY", c->name, c->hostname, to_name);
337 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
338 char *address, *port;
339 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
340 sockaddr2str(&from->address, &address, &port);
341 send_request(to->nexthop->connection, "%s %s %s", request, address, port);
347 return send_request(to->nexthop->connection, "%s", request);
350 /* Don't use key material until every check has passed. */
351 cipher_close(&from->outcipher);
352 digest_close(&from->outdigest);
353 from->status.validkey = false;
355 if(compression < 0 || compression > 11) {
356 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
360 from->outcompression = compression;
362 /* SPTPS or old-style key exchange? */
364 if(from->status.sptps) {
365 char buf[strlen(key)];
366 int len = b64decode(key, buf, strlen(key));
368 if(!sptps_receive_data(&from->sptps, buf, len))
369 logger(DEBUG_ALWAYS, LOG_ERR, "Error processing SPTPS data from %s (%s)", from->name, from->hostname);
371 if(from->status.validkey) {
372 if(*address && *port) {
373 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
374 sockaddr_t sa = str2sockaddr(address, port);
375 update_node_udp(from, &sa);
378 if(from->options & OPTION_PMTU_DISCOVERY)
379 send_mtu_probe(from);
385 /* Check and lookup cipher and digest algorithms */
387 if(!cipher_open_by_nid(&from->outcipher, cipher)) {
388 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
392 if(!digest_open_by_nid(&from->outdigest, digest, maclength)) {
393 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
397 if(maclength != digest_length(&from->outdigest)) {
398 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
404 keylen = hex2bin(key, key, sizeof key);
406 if(keylen != cipher_keylength(&from->outcipher)) {
407 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
411 /* Update our copy of the origin's packet key */
413 cipher_set_key(&from->outcipher, key, true);
414 digest_set_key(&from->outdigest, key, keylen);
416 from->status.validkey = true;
417 from->sent_seqno = 0;
419 if(*address && *port) {
420 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
421 sockaddr_t sa = str2sockaddr(address, port);
422 update_node_udp(from, &sa);
425 if(from->options & OPTION_PMTU_DISCOVERY)
426 send_mtu_probe(from);