2 protocol_key.c -- handle the meta-protocol, key exchange
3 Copyright (C) 1999-2005 Ivo Timmermans,
4 2000-2013 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);
107 logger(DEBUG_ALWAYS, LOG_DEBUG, "send_req_key(%s) called while sptps->label != NULL!", to->name);
109 char label[25 + strlen(myself->name) + strlen(to->name)];
110 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", myself->name, to->name);
111 sptps_stop(&to->sptps);
112 to->status.validkey = false;
113 to->status.waitingforkey = true;
114 to->last_req_key = now.tv_sec;
115 to->incompression = myself->incompression;
116 return sptps_start(&to->sptps, to, true, true, myself->connection->ecdsa, to->ecdsa, label, sizeof label, send_initial_sptps_data, receive_sptps_record);
119 return send_request(to->nexthop->connection, "%d %s %s", REQ_KEY, myself->name, to->name);
122 /* REQ_KEY is overloaded to allow arbitrary requests to be routed between two nodes. */
124 static bool req_key_ext_h(connection_t *c, const char *request, node_t *from, int reqno) {
127 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
128 send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
134 if(node_read_ecdsa_public_key(from)) {
135 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
139 char pubkey[MAX_STRING_SIZE];
140 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
141 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
145 logger(DEBUG_PROTOCOL, LOG_INFO, "Learned ECDSA public key from %s (%s)", from->name, from->hostname);
146 append_config_file(from->name, "ECDSAPublicKey", pubkey);
151 if(!node_read_ecdsa_public_key(from)) {
152 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No ECDSA key known for %s (%s)", from->name, from->hostname);
153 send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
157 if(from->sptps.label)
158 logger(DEBUG_ALWAYS, LOG_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
160 char buf[MAX_STRING_SIZE];
163 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
164 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS_START", from->name, from->hostname, "invalid SPTPS data");
168 char label[25 + strlen(from->name) + strlen(myself->name)];
169 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name);
170 sptps_stop(&from->sptps);
171 from->status.validkey = false;
172 from->status.waitingforkey = true;
173 from->last_req_key = now.tv_sec;
174 sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data, receive_sptps_record);
175 sptps_receive_data(&from->sptps, buf, len);
180 if(!from->status.validkey) {
181 logger(DEBUG_PROTOCOL, LOG_ERR, "Got REQ_SPTPS from %s (%s) but we don't have a valid key yet", from->name, from->hostname);
185 char buf[MAX_STRING_SIZE];
187 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
188 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS", from->name, from->hostname, "invalid SPTPS data");
191 sptps_receive_data(&from->sptps, buf, len);
196 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
201 bool req_key_h(connection_t *c, const char *request) {
202 char from_name[MAX_STRING_SIZE];
203 char to_name[MAX_STRING_SIZE];
207 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
208 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
213 if(!check_id(from_name) || !check_id(to_name)) {
214 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
218 from = lookup_node(from_name);
221 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
222 "REQ_KEY", c->name, c->hostname, from_name);
226 to = lookup_node(to_name);
229 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
230 "REQ_KEY", c->name, c->hostname, to_name);
234 /* Check if this key request is for us */
236 if(to == myself) { /* Yes */
237 /* Is this an extended REQ_KEY message? */
238 if(experimental && reqno)
239 return req_key_ext_h(c, request, from, reqno);
241 /* No, just send our key back */
247 if(!to->status.reachable) {
248 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
249 "REQ_KEY", c->name, c->hostname, to_name);
253 send_request(to->nexthop->connection, "%s", request);
259 bool send_ans_key(node_t *to) {
263 size_t keylen = cipher_keylength(myself->incipher);
264 char key[keylen * 2 + 1];
266 cipher_close(to->incipher);
267 digest_close(to->indigest);
269 to->incipher = cipher_open_by_nid(cipher_get_nid(myself->incipher));
270 to->indigest = digest_open_by_nid(digest_get_nid(myself->indigest), digest_length(myself->indigest));
271 to->incompression = myself->incompression;
273 if(!to->incipher || !to->indigest)
276 randomize(key, keylen);
277 if(!cipher_set_key(to->incipher, key, false))
279 if(!digest_set_key(to->indigest, key, keylen))
282 bin2hex(key, key, keylen);
284 // Reset sequence number and late packet window
286 to->received_seqno = 0;
288 if(replaywin) memset(to->late, 0, replaywin);
290 return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
291 myself->name, to->name, key,
292 cipher_get_nid(to->incipher),
293 digest_get_nid(to->indigest),
294 (int)digest_length(to->indigest),
298 bool ans_key_h(connection_t *c, const char *request) {
299 char from_name[MAX_STRING_SIZE];
300 char to_name[MAX_STRING_SIZE];
301 char key[MAX_STRING_SIZE];
302 char address[MAX_STRING_SIZE] = "";
303 char port[MAX_STRING_SIZE] = "";
304 int cipher, digest, maclength, compression, keylen;
307 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
308 from_name, to_name, key, &cipher, &digest, &maclength,
309 &compression, address, port) < 7) {
310 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
315 if(!check_id(from_name) || !check_id(to_name)) {
316 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
320 from = lookup_node(from_name);
323 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
324 "ANS_KEY", c->name, c->hostname, from_name);
328 to = lookup_node(to_name);
331 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
332 "ANS_KEY", c->name, c->hostname, to_name);
336 /* Forward it if necessary */
342 if(!to->status.reachable) {
343 logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
344 "ANS_KEY", c->name, c->hostname, to_name);
348 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
349 char *address, *port;
350 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
351 sockaddr2str(&from->address, &address, &port);
352 send_request(to->nexthop->connection, "%s %s %s", request, address, port);
358 return send_request(to->nexthop->connection, "%s", request);
361 /* Don't use key material until every check has passed. */
362 cipher_close(from->outcipher);
363 digest_close(from->outdigest);
364 from->status.validkey = false;
366 if(compression < 0 || compression > 11) {
367 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
371 from->outcompression = compression;
373 /* SPTPS or old-style key exchange? */
375 if(from->status.sptps) {
376 char buf[strlen(key)];
377 int len = b64decode(key, buf, strlen(key));
379 if(!len || !sptps_receive_data(&from->sptps, buf, len))
380 logger(DEBUG_ALWAYS, LOG_ERR, "Error processing SPTPS data from %s (%s)", from->name, from->hostname);
382 if(from->status.validkey) {
383 if(*address && *port) {
384 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
385 sockaddr_t sa = str2sockaddr(address, port);
386 update_node_udp(from, &sa);
389 if(from->options & OPTION_PMTU_DISCOVERY && !(from->options & OPTION_TCPONLY))
390 send_mtu_probe(from);
396 /* Check and lookup cipher and digest algorithms */
398 if(!(from->outcipher = cipher_open_by_nid(cipher))) {
399 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
403 if(!(from->outdigest = digest_open_by_nid(digest, maclength))) {
404 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
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);