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_initial_sptps_data(void *handle, uint8_t type, const void *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 Ed25519 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 if(!node_read_ecdsa_public_key(from)) {
128 /* Request their key *before* we send our key back. Otherwise the first SPTPS packet from them will get dropped. */
129 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Preemptively requesting Ed25519 key for %s (%s)", from->name, from->hostname);
130 send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
132 char *pubkey = ecdsa_get_base64_public_key(myself->connection->ecdsa);
133 send_request(from->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, from->name, ANS_PUBKEY, pubkey);
139 if(node_read_ecdsa_public_key(from)) {
140 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got ANS_PUBKEY from %s (%s) even though we already have his pubkey", from->name, from->hostname);
144 char pubkey[MAX_STRING_SIZE];
145 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, pubkey) != 1 || !(from->ecdsa = ecdsa_set_base64_public_key(pubkey))) {
146 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_PUBKEY", from->name, from->hostname, "invalid pubkey");
150 logger(DEBUG_PROTOCOL, LOG_INFO, "Learned Ed25519 public key from %s (%s)", from->name, from->hostname);
151 append_config_file(from->name, "Ed25519PublicKey", pubkey);
156 if(!node_read_ecdsa_public_key(from)) {
157 logger(DEBUG_PROTOCOL, LOG_DEBUG, "No Ed25519 key known for %s (%s)", from->name, from->hostname);
158 send_request(from->nexthop->connection, "%d %s %s %d", REQ_KEY, myself->name, from->name, REQ_PUBKEY);
162 if(from->sptps.label)
163 logger(DEBUG_ALWAYS, LOG_DEBUG, "Got REQ_KEY from %s while we already started a SPTPS session!", from->name);
165 char buf[MAX_STRING_SIZE];
168 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
169 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS_START", from->name, from->hostname, "invalid SPTPS data");
173 char label[25 + strlen(from->name) + strlen(myself->name)];
174 snprintf(label, sizeof label, "tinc UDP key expansion %s %s", from->name, myself->name);
175 sptps_stop(&from->sptps);
176 from->status.validkey = false;
177 from->status.waitingforkey = true;
178 from->last_req_key = now.tv_sec;
179 sptps_start(&from->sptps, from, false, true, myself->connection->ecdsa, from->ecdsa, label, sizeof label, send_sptps_data, receive_sptps_record);
180 sptps_receive_data(&from->sptps, buf, len);
181 send_mtu_info(myself, from, MTU);
186 if(!from->status.validkey) {
187 logger(DEBUG_PROTOCOL, LOG_ERR, "Got REQ_SPTPS from %s (%s) but we don't have a valid key yet", from->name, from->hostname);
191 char buf[MAX_STRING_SIZE];
193 if(sscanf(request, "%*d %*s %*s %*d " MAX_STRING, buf) != 1 || !(len = b64decode(buf, buf, strlen(buf)))) {
194 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_SPTPS", from->name, from->hostname, "invalid SPTPS data");
197 sptps_receive_data(&from->sptps, buf, len);
198 send_mtu_info(myself, from, MTU);
203 logger(DEBUG_ALWAYS, LOG_ERR, "Unknown extended REQ_KEY request from %s (%s): %s", from->name, from->hostname, request);
208 bool req_key_h(connection_t *c, const char *request) {
209 char from_name[MAX_STRING_SIZE];
210 char to_name[MAX_STRING_SIZE];
214 if(sscanf(request, "%*d " MAX_STRING " " MAX_STRING " %d", from_name, to_name, &reqno) < 2) {
215 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "REQ_KEY", c->name,
220 if(!check_id(from_name) || !check_id(to_name)) {
221 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "REQ_KEY", c->name, c->hostname, "invalid name");
225 from = lookup_node(from_name);
228 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
229 "REQ_KEY", c->name, c->hostname, from_name);
233 to = lookup_node(to_name);
236 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
237 "REQ_KEY", c->name, c->hostname, to_name);
241 /* If this is a SPTPS packet, see if sending UDP info helps.
242 Note that we only do this if we're the destination or the static relay;
243 otherwise every hop would initiate its own UDP info message, resulting in elevated chatter. */
245 if(experimental && (reqno == REQ_KEY || reqno == REQ_SPTPS) && to->via == myself)
246 send_udp_info(myself, from);
248 /* Check if this key request is for us */
250 if(to == myself) { /* Yes */
251 /* Is this an extended REQ_KEY message? */
252 if(experimental && reqno)
253 return req_key_ext_h(c, request, from, reqno);
255 /* No, just send our key back */
261 if(!to->status.reachable) {
262 logger(DEBUG_PROTOCOL, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
263 "REQ_KEY", c->name, c->hostname, to_name);
267 /* TODO: forwarding SPTPS packets in this way is inefficient because we send them over TCP without checking for UDP connectivity */
268 send_request(to->nexthop->connection, "%s", request);
274 bool send_ans_key(node_t *to) {
278 #ifdef DISABLE_LEGACY
281 size_t keylen = myself->incipher ? cipher_keylength(myself->incipher) : 1;
282 char key[keylen * 2 + 1];
284 randomize(key, keylen);
286 cipher_close(to->incipher);
287 digest_close(to->indigest);
289 if(myself->incipher) {
290 to->incipher = cipher_open_by_nid(cipher_get_nid(myself->incipher));
293 if(!cipher_set_key(to->incipher, key, false))
297 if(myself->indigest) {
298 to->indigest = digest_open_by_nid(digest_get_nid(myself->indigest), digest_length(myself->indigest));
301 if(!digest_set_key(to->indigest, key, keylen))
305 to->incompression = myself->incompression;
307 bin2hex(key, key, keylen);
309 // Reset sequence number and late packet window
311 to->received_seqno = 0;
313 if(replaywin) memset(to->late, 0, replaywin);
315 to->status.validkey_in = true;
317 return send_request(to->nexthop->connection, "%d %s %s %s %d %d %d %d", ANS_KEY,
318 myself->name, to->name, key,
319 cipher_get_nid(to->incipher),
320 digest_get_nid(to->indigest),
321 (int)digest_length(to->indigest),
326 bool ans_key_h(connection_t *c, const char *request) {
327 char from_name[MAX_STRING_SIZE];
328 char to_name[MAX_STRING_SIZE];
329 char key[MAX_STRING_SIZE];
330 char address[MAX_STRING_SIZE] = "";
331 char port[MAX_STRING_SIZE] = "";
332 int cipher, digest, maclength, compression, keylen;
335 if(sscanf(request, "%*d "MAX_STRING" "MAX_STRING" "MAX_STRING" %d %d %d %d "MAX_STRING" "MAX_STRING,
336 from_name, to_name, key, &cipher, &digest, &maclength,
337 &compression, address, port) < 7) {
338 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s)", "ANS_KEY", c->name,
343 if(!check_id(from_name) || !check_id(to_name)) {
344 logger(DEBUG_ALWAYS, LOG_ERR, "Got bad %s from %s (%s): %s", "ANS_KEY", c->name, c->hostname, "invalid name");
348 from = lookup_node(from_name);
351 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) origin %s which does not exist in our connection list",
352 "ANS_KEY", c->name, c->hostname, from_name);
356 to = lookup_node(to_name);
359 logger(DEBUG_ALWAYS, LOG_ERR, "Got %s from %s (%s) destination %s which does not exist in our connection list",
360 "ANS_KEY", c->name, c->hostname, to_name);
364 /* Forward it if necessary */
370 if(!to->status.reachable) {
371 logger(DEBUG_ALWAYS, LOG_WARNING, "Got %s from %s (%s) destination %s which is not reachable",
372 "ANS_KEY", c->name, c->hostname, to_name);
376 if(!*address && from->address.sa.sa_family != AF_UNSPEC) {
377 char *address, *port;
378 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Appending reflexive UDP address to ANS_KEY from %s to %s", from->name, to->name);
379 sockaddr2str(&from->address, &address, &port);
380 send_request(to->nexthop->connection, "%s %s %s", request, address, port);
386 return send_request(to->nexthop->connection, "%s", request);
389 #ifndef DISABLE_LEGACY
390 /* Don't use key material until every check has passed. */
391 cipher_close(from->outcipher);
392 digest_close(from->outdigest);
394 from->status.validkey = false;
396 if(compression < 0 || compression > 11) {
397 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus compression level!", from->name, from->hostname);
401 from->outcompression = compression;
403 /* SPTPS or old-style key exchange? */
405 if(from->status.sptps) {
406 char buf[strlen(key)];
407 int len = b64decode(key, buf, strlen(key));
409 if(!len || !sptps_receive_data(&from->sptps, buf, len))
410 logger(DEBUG_ALWAYS, LOG_ERR, "Error processing SPTPS data from %s (%s)", from->name, from->hostname);
412 if(from->status.validkey) {
413 if(*address && *port) {
414 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
415 sockaddr_t sa = str2sockaddr(address, port);
416 update_node_udp(from, &sa);
420 send_mtu_info(myself, from, MTU);
425 #ifdef DISABLE_LEGACY
426 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses legacy protocol!", from->name, from->hostname);
429 /* Check and lookup cipher and digest algorithms */
432 if(!(from->outcipher = cipher_open_by_nid(cipher))) {
433 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown cipher!", from->name, from->hostname);
437 from->outcipher = NULL;
441 if(!(from->outdigest = digest_open_by_nid(digest, maclength))) {
442 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses unknown digest!", from->name, from->hostname);
446 from->outdigest = NULL;
449 if(maclength != digest_length(from->outdigest)) {
450 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses bogus MAC length!", from->name, from->hostname);
456 keylen = hex2bin(key, key, sizeof key);
458 if(keylen != (from->outcipher ? cipher_keylength(from->outcipher) : 1)) {
459 logger(DEBUG_ALWAYS, LOG_ERR, "Node %s (%s) uses wrong keylength!", from->name, from->hostname);
463 /* Update our copy of the origin's packet key */
465 if(from->outcipher && !cipher_set_key(from->outcipher, key, true))
467 if(from->outdigest && !digest_set_key(from->outdigest, key, keylen))
470 from->status.validkey = true;
471 from->sent_seqno = 0;
473 if(*address && *port) {
474 logger(DEBUG_PROTOCOL, LOG_DEBUG, "Using reflexive UDP address from %s: %s port %s", from->name, address, port);
475 sockaddr_t sa = str2sockaddr(address, port);
476 update_node_udp(from, &sa);