2 protocol_key.c -- handle the meta-protocol, key exchange
3 Copyright (C) 1999-2005 Ivo Timmermans,
4 2000-2014 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->edge && 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_sptps_data_myself(void *handle, uint8_t type, const void *data, size_t len) {
91 return send_sptps_data(handle, myself, type, data, len);
94 static bool send_initial_sptps_data(void *handle, uint8_t type, const void *data, size_t len) {
96 to->sptps.send_data = send_sptps_data_myself;
97 char buf[len * 4 / 3 + 5];
98 b64encode(data, buf, len);
99 return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_KEY, buf);
102 bool send_req_key(node_t *to) {
103 if(to->status.sptps) {
104 if(!node_read_ecdsa_public_key(to)) {
105 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No Ed25519 key known for %s (%s)", to->name, to->hostname);
106 send_request(to->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, to->name, REQ_PUBKEY);
111 logger(DEBUG_ALWAYS, LOG_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
113 char label[25 + strlen(myself->name) + strlen(to->name)];
114 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", myself->name, to->name);
115 sptps_stop(&to->sptps);
116 to->status.validkey = false;
117 to->status.waitingforkey = true;
118 to->last_req_key = now.tv_sec;
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 if(!node_read_ecdsa_public_key(from)) {
132 /* Request their key *before* we send our key back. Otherwise the first SPTPS packet from them will get dropped. */
133 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Preemptively requesting Ed25519 key for %s (%s)", from->name, from->hostname);
134 send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
136 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
137 send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
143 if(node_read_ecdsa_public_key(from)) {
144 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
148 char pubkey[MAX_STRING_SIZE];
149 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
150 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
154 logger(DEBUG_PROTOCOL, LOG_INFO, "Learned Ed25519 public key from %s (%s)", from->name, from->hostname);
155 append_config_file(from->name, "Ed25519PublicKey", pubkey);
160 if(!node_read_ecdsa_public_key(from)) {
161 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No Ed25519 key known for %s (%s)", from->name, from->hostname);
162 send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
166 if(from->sptps.label)
167 logger(DEBUG_ALWAYS, LOG_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
169 char buf[MAX_STRING_SIZE];
172 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
173 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS_START", from->name, from->hostname, "invalid SPTPS data");
177 char label[25 + strlen(from->name) + strlen(myself->name)];
178 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name);
179 sptps_stop(&from->sptps);
180 from->status.validkey = false;
181 from->status.waitingforkey = true;
182 from->last_req_key = now.tv_sec;
183 sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data_myself, receive_sptps_record);
184 sptps_receive_data(&from->sptps, buf, len);
185 send_mtu_info(myself, from, MTU);
190 if(!from->status.validkey) {
191 logger(DEBUG_PROTOCOL, LOG_ERR, "Got REQ_SPTPS from %s (%s) but we don't have a valid key yet", from->name, from->hostname);
195 char buf[MAX_STRING_SIZE];
197 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
198 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS", from->name, from->hostname, "invalid SPTPS data");
201 sptps_receive_data(&from->sptps, buf, len);
202 send_mtu_info(myself, from, MTU);
207 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
212 bool req_key_h(connection_t *c, const char *request) {
213 char from_name[MAX_STRING_SIZE];
214 char to_name[MAX_STRING_SIZE];
218 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
219 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
224 if(!check_id(from_name) || !check_id(to_name)) {
225 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
229 from = lookup_node(from_name);
232 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
233 "REQ_KEY", c->name, c->hostname, from_name);
237 to = lookup_node(to_name);
240 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
241 "REQ_KEY", c->name, c->hostname, to_name);
245 /* If this is a SPTPS packet, see if sending UDP info helps.
246 Note that we only do this if we're the destination or the static relay;
247 otherwise every hop would initiate its own UDP info message, resulting in elevated chatter. */
249 if(experimental && (reqno == REQ_KEY || reqno == REQ_SPTPS) && to->via == myself)
250 send_udp_info(myself, from);
252 /* Check if this key request is for us */
254 if(to == myself) { /* Yes */
255 /* Is this an extended REQ_KEY message? */
256 if(experimental && reqno)
257 return req_key_ext_h(c, request, from, reqno);
259 /* No, just send our key back */
265 if(!to->status.reachable) {
266 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
267 "REQ_KEY", c->name, c->hostname, to_name);
271 /* TODO: forwarding SPTPS packets in this way is inefficient because we send them over TCP without checking for UDP connectivity */
272 send_request(to->nexthop->connection, "%s", request);
278 bool send_ans_key(node_t *to) {
282 #ifdef DISABLE_LEGACY
285 size_t keylen = myself->incipher ? cipher_keylength(myself->incipher) : 1;
286 char key[keylen * 2 + 1];
288 randomize(key, keylen);
290 cipher_close(to->incipher);
291 digest_close(to->indigest);
293 if(myself->incipher) {
294 to->incipher = cipher_open_by_nid(cipher_get_nid(myself->incipher));
297 if(!cipher_set_key(to->incipher, key, false))
301 if(myself->indigest) {
302 to->indigest = digest_open_by_nid(digest_get_nid(myself->indigest), digest_length(myself->indigest));
305 if(!digest_set_key(to->indigest, key, keylen))
309 to->incompression = myself->incompression;
311 bin2hex(key, key, keylen);
313 // Reset sequence number and late packet window
315 to->received_seqno = 0;
317 if(replaywin) memset(to->late, 0, replaywin);
319 to->status.validkey_in = true;
321 return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
322 myself->name, to->name, key,
323 cipher_get_nid(to->incipher),
324 digest_get_nid(to->indigest),
325 (int)digest_length(to->indigest),
330 bool ans_key_h(connection_t *c, const char *request) {
331 char from_name[MAX_STRING_SIZE];
332 char to_name[MAX_STRING_SIZE];
333 char key[MAX_STRING_SIZE];
334 char address[MAX_STRING_SIZE] = "";
335 char port[MAX_STRING_SIZE] = "";
336 int cipher, digest, maclength, compression, keylen;
339 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
340 from_name, to_name, key, &cipher, &digest, &maclength,
341 &compression, address, port) < 7) {
342 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
347 if(!check_id(from_name) || !check_id(to_name)) {
348 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
352 from = lookup_node(from_name);
355 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
356 "ANS_KEY", c->name, c->hostname, from_name);
360 to = lookup_node(to_name);
363 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
364 "ANS_KEY", c->name, c->hostname, to_name);
368 /* Forward it if necessary */
374 if(!to->status.reachable) {
375 logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
376 "ANS_KEY", c->name, c->hostname, to_name);
380 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
381 char *address, *port;
382 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
383 sockaddr2str(&from->address, &address, &port);
384 send_request(to->nexthop->connection, "%s %s %s", request, address, port);
390 return send_request(to->nexthop->connection, "%s", request);
393 #ifndef DISABLE_LEGACY
394 /* Don't use key material until every check has passed. */
395 cipher_close(from->outcipher);
396 digest_close(from->outdigest);
398 from->status.validkey = false;
400 if(compression < 0 || compression > 11) {
401 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
405 from->outcompression = compression;
407 /* SPTPS or old-style key exchange? */
409 if(from->status.sptps) {
410 char buf[strlen(key)];
411 int len = b64decode(key, buf, strlen(key));
413 if(!len || !sptps_receive_data(&from->sptps, buf, len))
414 logger(DEBUG_ALWAYS, LOG_ERR, "Error processing SPTPS data from %s (%s)", from->name, from->hostname);
416 if(from->status.validkey) {
417 if(*address && *port) {
418 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
419 sockaddr_t sa = str2sockaddr(address, port);
420 update_node_udp(from, &sa);
424 send_mtu_info(myself, from, MTU);
429 #ifdef DISABLE_LEGACY
430 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses legacy protocol!", from->name, from->hostname);
433 /* Check and lookup cipher and digest algorithms */
436 if(!(from->outcipher = cipher_open_by_nid(cipher))) {
437 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
441 from->outcipher = NULL;
445 if(!(from->outdigest = digest_open_by_nid(digest, maclength))) {
446 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
450 from->outdigest = NULL;
453 if(maclength != digest_length(from->outdigest)) {
454 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
460 keylen = hex2bin(key, key, sizeof key);
462 if(keylen != (from->outcipher ? cipher_keylength(from->outcipher) : 1)) {
463 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
467 /* Update our copy of the origin's packet key */
469 if(from->outcipher && !cipher_set_key(from->outcipher, key, true))
471 if(from->outdigest && !digest_set_key(from->outdigest, key, keylen))
474 from->status.validkey = true;
475 from->sent_seqno = 0;
477 if(*address && *port) {
478 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
479 sockaddr_t sa = str2sockaddr(address, port);
480 update_node_udp(from, &sa);