2 protocol_key.c -- handle the meta-protocol, key exchange
3 Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23 #include "connection.h"
35 static bool mykeyused = false;
37 void send_key_changed(void) {
38 send_request(everyone, "%d %x %s", KEY_CHANGED, rand(), myself->name);
40 /* Immediately send new keys to directly connected nodes to keep UDP mappings alive */
42 for list_each(connection_t, c, connection_list)
43 if(c->status.active && c->node && c->node->status.reachable && !c->node->status.sptps)
44 send_ans_key(c->node);
46 /* Force key exchange for connections using SPTPS */
49 for splay_each(node_t, n, node_tree)
50 if(n->status.reachable && n->status.validkey && n->status.sptps)
51 sptps_force_kex(&n->sptps);
55 bool key_changed_h(connection_t *c, const char *request) {
56 char name[MAX_STRING_SIZE];
59 if(sscanf(request, "%*d %*x " MAX_STRING, name) != 1) {
60 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "KEY_CHANGED",
61 c->name, c->hostname);
65 if(seen_request(request))
68 n = lookup_node(name);
71 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist",
72 "KEY_CHANGED", c->name, c->hostname, name);
76 if(!n->status.sptps) {
77 n->status.validkey = false;
83 forward_request(c, request);
88 static bool send_initial_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
90 to->sptps.send_data = send_sptps_data;
91 char buf[len * 4 / 3 + 5];
92 b64encode(data, buf, len);
93 return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_KEY, buf);
96 bool send_req_key(node_t *to) {
97 if(to->status.sptps) {
98 if(!node_read_ecdsa_public_key(to)) {
99 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No ECDSA key known for %s (%s)", to->name, to->hostname);
100 send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, REQ_PUBKEY);
105 logger(DEBUG_ALWAYS, LOG_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
107 char label[25 + strlen(myself->name) + strlen(to->name)];
108 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", myself->name, to->name);
109 sptps_stop(&to->sptps);
110 to->status.validkey = false;
111 to->status.waitingforkey = true;
112 to->last_req_key = now.tv_sec;
113 to->incompression = myself->incompression;
114 return sptps_start(&to->sptps, to, true, true, myself->connection->ecdsa, to->ecdsa, label, sizeof label, send_initial_sptps_data, receive_sptps_record);
117 return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
120 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
122 static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, int reqno) {
125 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
126 send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
132 if(node_read_ecdsa_public_key(from)) {
133 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
137 char pubkey[MAX_STRING_SIZE];
138 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
139 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
143 logger(DEBUG_PROTOCOL, LOG_INFO, "Learned ECDSA public key from %s (%s)", from->name, from->hostname);
144 append_config_file(from->name, "ECDSAPublicKey", pubkey);
149 if(!node_read_ecdsa_public_key(from)) {
150 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No ECDSA key known for %s (%s)", from->name, from->hostname);
151 send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
155 if(from->sptps.label)
156 logger(DEBUG_ALWAYS, LOG_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
158 char buf[MAX_STRING_SIZE];
161 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
162 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS_START", from->name, from->hostname, "invalid SPTPS data");
166 char label[25 + strlen(from->name) + strlen(myself->name)];
167 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name);
168 sptps_stop(&from->sptps);
169 from->status.validkey = false;
170 from->status.waitingforkey = true;
171 from->last_req_key = now.tv_sec;
172 sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data, receive_sptps_record);
173 sptps_receive_data(&from->sptps, buf, len);
178 if(!from->status.validkey) {
179 logger(DEBUG_PROTOCOL, LOG_ERR, "Got REQ_SPTPS from %s (%s) but we don't have a valid key yet", from->name, from->hostname);
183 char buf[MAX_STRING_SIZE];
185 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
186 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS", from->name, from->hostname, "invalid SPTPS data");
189 sptps_receive_data(&from->sptps, buf, len);
194 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
199 bool req_key_h(connection_t *c, const char *request) {
200 char from_name[MAX_STRING_SIZE];
201 char to_name[MAX_STRING_SIZE];
205 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
206 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
211 if(!check_id(from_name) || !check_id(to_name)) {
212 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
216 from = lookup_node(from_name);
219 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
220 "REQ_KEY", c->name, c->hostname, from_name);
224 to = lookup_node(to_name);
227 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
228 "REQ_KEY", c->name, c->hostname, to_name);
232 /* Check if this key request is for us */
234 if(to == myself) { /* Yes */
235 /* Is this an extended REQ_KEY message? */
236 if(experimental && reqno)
237 return req_key_ext_h(c, request, from, reqno);
239 /* 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 to->incipher = cipher_open_by_nid(cipher_get_nid(myself->incipher));
265 to->indigest = digest_open_by_nid(digest_get_nid(myself->indigest), digest_length(myself->indigest));
266 to->incompression = myself->incompression;
268 if(!to->incipher || !to->indigest)
271 randomize(key, keylen);
272 if(!cipher_set_key(to->incipher, key, false))
274 if(!digest_set_key(to->indigest, key, keylen))
277 bin2hex(key, key, keylen);
279 // Reset sequence number and late packet window
281 to->received_seqno = 0;
283 if(replaywin) memset(to->late, 0, replaywin);
285 return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
286 myself->name, to->name, key,
287 cipher_get_nid(to->incipher),
288 digest_get_nid(to->indigest),
289 (int)digest_length(to->indigest),
293 bool ans_key_h(connection_t *c, const char *request) {
294 char from_name[MAX_STRING_SIZE];
295 char to_name[MAX_STRING_SIZE];
296 char key[MAX_STRING_SIZE];
297 char address[MAX_STRING_SIZE] = "";
298 char port[MAX_STRING_SIZE] = "";
299 int cipher, digest, maclength, compression, keylen;
302 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
303 from_name, to_name, key, &cipher, &digest, &maclength,
304 &compression, address, port) < 7) {
305 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
310 if(!check_id(from_name) || !check_id(to_name)) {
311 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
315 from = lookup_node(from_name);
318 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
319 "ANS_KEY", c->name, c->hostname, from_name);
323 to = lookup_node(to_name);
326 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
327 "ANS_KEY", c->name, c->hostname, to_name);
331 /* Forward it if necessary */
334 if(!to->status.reachable) {
335 logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
336 "ANS_KEY", c->name, c->hostname, to_name);
340 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
341 char *address, *port;
342 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
343 sockaddr2str(&from->address, &address, &port);
344 send_request(to->nexthop->connection, "%s %s %s", request, address, port);
350 return send_request(to->nexthop->connection, "%s", request);
353 /* Don't use key material until every check has passed. */
354 cipher_close(from->outcipher);
355 digest_close(from->outdigest);
356 from->status.validkey = false;
358 if(compression < 0 || compression > 11) {
359 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
363 from->outcompression = compression;
365 /* SPTPS or old-style key exchange? */
367 if(from->status.sptps) {
368 char buf[strlen(key)];
369 int len = b64decode(key, buf, strlen(key));
371 if(!len || !sptps_receive_data(&from->sptps, buf, len))
372 logger(DEBUG_ALWAYS, LOG_ERR, "Error processing SPTPS data from %s (%s)", from->name, from->hostname);
374 if(from->status.validkey) {
375 if(*address && *port) {
376 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
377 sockaddr_t sa = str2sockaddr(address, port);
378 update_node_udp(from, &sa);
381 if(from->options & OPTION_PMTU_DISCOVERY && !(from->options & OPTION_TCPONLY))
382 send_mtu_probe(from);
388 /* Check and lookup cipher and digest algorithms */
391 if(!(from->outcipher = cipher_open_by_nid(cipher))) {
392 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
396 from->outcipher = NULL;
400 if(!(from->outdigest = digest_open_by_nid(digest, maclength))) {
401 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
405 from->outdigest = NULL;
408 if(maclength != digest_length(from->outdigest)) {
409 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
415 keylen = hex2bin(key, key, sizeof key);
417 if(keylen != cipher_keylength(from->outcipher)) {
418 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
422 /* Update our copy of the origin's packet key */
424 if(!cipher_set_key(from->outcipher, key, true))
426 if(!digest_set_key(from->outdigest, key, keylen))
429 from->status.validkey = true;
430 from->sent_seqno = 0;
432 if(*address && *port) {
433 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
434 sockaddr_t sa = str2sockaddr(address, port);
435 update_node_udp(from, &sa);
438 if(from->options & OPTION_PMTU_DISCOVERY && !(from->options & OPTION_TCPONLY))
439 send_mtu_probe(from);