2 protocol_auth.c -- handle the meta-protocol, authentication
3 Copyright (C) 1999-2005 Ivo Timmermans,
4 2000-2010 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.
23 #include "splay_tree.h"
25 #include "connection.h"
27 #include "control_common.h"
43 bool send_id(connection_t *c) {
44 gettimeofday(&c->start, NULL);
49 if(c->config_tree && !read_ecdsa_public_key(c))
52 minor = myself->connection->protocol_minor;
55 return send_request(c, "%d %s %d.%d", ID, myself->connection->name, myself->connection->protocol_major, minor);
58 bool id_h(connection_t *c, char *request) {
59 char name[MAX_STRING_SIZE];
61 if(sscanf(request, "%*d " MAX_STRING " %d.%d", name, &c->protocol_major, &c->protocol_minor) < 2) {
62 logger(LOG_ERR, "Got bad %s from %s (%s)", "ID", c->name,
67 /* Check if this is a control connection */
69 if(name[0] == '^' && !strcmp(name + 1, controlcookie)) {
70 c->status.control = true;
71 c->allow_request = CONTROL;
72 c->last_ping_time = time(NULL) + 3600;
73 return send_request(c, "%d %d %d", ACK, TINC_CTL_VERSION_CURRENT, getpid());
76 /* Check if identity is a valid name */
79 logger(LOG_ERR, "Got bad %s from %s (%s): %s", "ID", c->name,
80 c->hostname, "invalid name");
84 /* If this is an outgoing connection, make sure we are connected to the right host */
87 if(strcmp(c->name, name)) {
88 logger(LOG_ERR, "Peer %s is %s instead of %s", c->hostname, name,
95 c->name = xstrdup(name);
98 /* Check if version matches */
100 if(c->protocol_major != myself->connection->protocol_major) {
101 logger(LOG_ERR, "Peer %s (%s) uses incompatible version %d.%d",
102 c->name, c->hostname, c->protocol_major, c->protocol_minor);
106 if(bypass_security) {
108 init_configuration(&c->config_tree);
109 c->allow_request = ACK;
113 if(!c->config_tree) {
114 init_configuration(&c->config_tree);
116 if(!read_connection_config(c)) {
117 logger(LOG_ERR, "Peer %s had unknown identity (%s)", c->hostname,
122 if(experimental && c->protocol_minor >= 2)
123 if(!read_ecdsa_public_key(c))
126 if(!ecdsa_active(&c->ecdsa))
127 c->protocol_minor = 1;
131 c->protocol_minor = 0;
133 c->allow_request = METAKEY;
135 if(c->protocol_minor >= 2)
136 return send_metakey_ec(c);
138 return send_metakey(c);
141 bool send_metakey_ec(connection_t *c) {
142 logger(LOG_DEBUG, "Sending ECDH metakey to %s", c->name);
144 size_t siglen = ecdsa_size(&myself->connection->ecdsa);
149 // TODO: include nonce? Use relevant parts of SSH or TLS protocol
151 if(!ecdh_generate_public(&c->ecdh, key))
154 if(!ecdsa_sign(&myself->connection->ecdsa, key, ECDH_SIZE, sig))
157 char out[MAX_STRING_SIZE];
159 bin2hex(key, out, ECDH_SIZE);
160 bin2hex(sig, out + ECDH_SIZE * 2, siglen);
161 out[(ECDH_SIZE + siglen) * 2] = 0;
163 bool result = send_request(c, "%d %s", METAKEY, out);
166 bool send_metakey(connection_t *c) {
167 if(!read_rsa_public_key(c))
170 if(!cipher_open_blowfish_ofb(&c->outcipher))
173 if(!digest_open_sha1(&c->outdigest, -1))
176 size_t len = rsa_size(&c->rsa);
179 char hexkey[2 * len + 1];
181 /* Create a random key */
185 /* The message we send must be smaller than the modulus of the RSA key.
186 By definition, for a key of k bits, the following formula holds:
188 2^(k-1) <= modulus < 2^(k)
190 Where ^ means "to the power of", not "xor".
191 This means that to be sure, we must choose our message < 2^(k-1).
192 This can be done by setting the most significant bit to zero.
197 cipher_set_key_from_rsa(&c->outcipher, key, len, true);
199 ifdebug(SCARY_THINGS) {
200 bin2hex(key, hexkey, len);
201 hexkey[len * 2] = '\0';
202 logger(LOG_DEBUG, "Generated random meta key (unencrypted): %s", hexkey);
205 /* Encrypt the random data
207 We do not use one of the PKCS padding schemes here.
208 This is allowed, because we encrypt a totally random string
209 with a length equal to that of the modulus of the RSA key.
212 if(!rsa_public_encrypt(&c->rsa, key, len, enckey)) {
213 logger(LOG_ERR, "Error during encryption of meta key for %s (%s)", c->name, c->hostname);
217 /* Convert the encrypted random data to a hexadecimal formatted string */
219 bin2hex(enckey, hexkey, len);
220 hexkey[len * 2] = '\0';
222 /* Send the meta key */
224 bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
225 cipher_get_nid(&c->outcipher),
226 digest_get_nid(&c->outdigest), c->outmaclength,
227 c->outcompression, hexkey);
229 c->status.encryptout = true;
233 static bool metakey_ec_h(connection_t *c, const char *request) {
234 size_t siglen = ecdsa_size(&c->ecdsa);
235 char in[MAX_STRING_SIZE];
236 char key[MAX_STRING_SIZE];
239 logger(LOG_DEBUG, "Got ECDH metakey from %s", c->name);
241 if(sscanf(request, "%*d " MAX_STRING, in) != 1) {
242 logger(LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
246 if(strlen(in) != (ECDH_SIZE + siglen) * 2) {
247 logger(LOG_ERR, "Possible intruder %s (%s): %s %d != %d", c->name, c->hostname, "wrong keylength", strlen(in) / 2, (ECDH_SIZE + siglen));
251 hex2bin(in, key, ECDH_SIZE);
252 hex2bin(in + ECDH_SIZE * 2, sig, siglen);
254 if(!ecdsa_verify(&c->ecdsa, key, ECDH_SIZE, sig)) {
255 logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "invalid ECDSA signature");
259 char shared[ECDH_SHARED_SIZE * 2 + 1];
261 if(!ecdh_compute_shared(&c->ecdh, key, shared))
264 /* Update our crypto end */
266 if(!cipher_open_by_name(&c->incipher, "aes-256-ofb"))
268 if(!digest_open_by_name(&c->indigest, "sha512", -1))
270 if(!cipher_open_by_name(&c->outcipher, "aes-256-ofb"))
272 if(!digest_open_by_name(&c->outdigest, "sha512", -1))
275 size_t mykeylen = cipher_keylength(&c->incipher);
276 size_t hiskeylen = cipher_keylength(&c->outcipher);
282 if(strcmp(myself->name, c->name) < 0) {
284 hiskey = key + mykeylen * 2;
285 xasprintf(&seed, "tinc TCP key expansion %s %s", myself->name, c->name);
287 mykey = key + hiskeylen * 2;
289 xasprintf(&seed, "tinc TCP key expansion %s %s", c->name, myself->name);
292 if(!prf(shared, ECDH_SHARED_SIZE, seed, strlen(seed), key, hiskeylen * 2 + mykeylen * 2))
297 bin2hex(shared, shared, ECDH_SHARED_SIZE);
298 shared[ECDH_SHARED_SIZE * 2] = 0;
299 logger(LOG_DEBUG, "Shared secret is %s", shared);
301 cipher_set_key(&c->incipher, mykey, true);
302 digest_set_key(&c->indigest, mykey + mykeylen, mykeylen);
304 cipher_set_key(&c->outcipher, hiskey, false);
305 digest_set_key(&c->outdigest, hiskey + hiskeylen, hiskeylen);
307 c->status.decryptin = true;
308 c->status.encryptout = true;
309 c->allow_request = CHALLENGE;
311 return send_challenge(c);
314 bool metakey_h(connection_t *c, char *request) {
315 if(c->protocol_minor >= 2)
316 return metakey_ec_h(c, request);
318 char hexkey[MAX_STRING_SIZE];
319 int cipher, digest, maclength, compression;
320 size_t len = rsa_size(&myself->connection->rsa);
324 if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
325 logger(LOG_ERR, "Got bad %s from %s (%s)", "METAKEY", c->name, c->hostname);
329 /* Check if the length of the meta key is all right */
331 if(strlen(hexkey) != len * 2) {
332 logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong keylength");
336 /* Convert the challenge from hexadecimal back to binary */
338 hex2bin(hexkey, enckey, len);
340 /* Decrypt the meta key */
342 if(!rsa_private_decrypt(&myself->connection->rsa, enckey, len, key)) {
343 logger(LOG_ERR, "Error during decryption of meta key for %s (%s)", c->name, c->hostname);
347 ifdebug(SCARY_THINGS) {
348 bin2hex(key, hexkey, len);
349 hexkey[len * 2] = '\0';
350 logger(LOG_DEBUG, "Received random meta key (unencrypted): %s", hexkey);
353 /* Check and lookup cipher and digest algorithms */
355 if(!cipher_open_by_nid(&c->incipher, cipher) || !cipher_set_key_from_rsa(&c->incipher, key, len, false)) {
356 logger(LOG_ERR, "Error during initialisation of cipher from %s (%s)", c->name, c->hostname);
360 if(!digest_open_by_nid(&c->indigest, digest, -1)) {
361 logger(LOG_ERR, "Error during initialisation of digest from %s (%s)", c->name, c->hostname);
365 c->status.decryptin = true;
367 c->allow_request = CHALLENGE;
369 return send_challenge(c);
372 bool send_challenge(connection_t *c) {
373 size_t len = c->protocol_minor >= 2 ? ECDH_SIZE : rsa_size(&c->rsa);
374 char buffer[len * 2 + 1];
377 c->hischallenge = xrealloc(c->hischallenge, len);
379 /* Copy random data to the buffer */
381 randomize(c->hischallenge, len);
385 bin2hex(c->hischallenge, buffer, len);
386 buffer[len * 2] = '\0';
388 /* Send the challenge */
390 return send_request(c, "%d %s", CHALLENGE, buffer);
393 bool challenge_h(connection_t *c, char *request) {
394 char buffer[MAX_STRING_SIZE];
395 size_t len = c->protocol_minor >= 2 ? ECDH_SIZE : rsa_size(&myself->connection->rsa);
396 size_t digestlen = digest_length(&c->indigest);
397 char digest[digestlen];
399 if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
400 logger(LOG_ERR, "Got bad %s from %s (%s)", "CHALLENGE", c->name, c->hostname);
404 /* Check if the length of the challenge is all right */
406 if(strlen(buffer) != len * 2) {
407 logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge length");
411 /* Convert the challenge from hexadecimal back to binary */
413 hex2bin(buffer, buffer, len);
415 c->allow_request = CHAL_REPLY;
417 /* Calculate the hash from the challenge we received */
419 digest_create(&c->indigest, buffer, len, digest);
421 /* Convert the hash to a hexadecimal formatted string */
423 bin2hex(digest, buffer, digestlen);
424 buffer[digestlen * 2] = '\0';
428 return send_request(c, "%d %s", CHAL_REPLY, buffer);
431 bool chal_reply_h(connection_t *c, char *request) {
432 char hishash[MAX_STRING_SIZE];
434 if(sscanf(request, "%*d " MAX_STRING, hishash) != 1) {
435 logger(LOG_ERR, "Got bad %s from %s (%s)", "CHAL_REPLY", c->name,
440 /* Check if the length of the hash is all right */
442 if(strlen(hishash) != digest_length(&c->outdigest) * 2) {
443 logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply length");
447 /* Convert the hash to binary format */
449 hex2bin(hishash, hishash, digest_length(&c->outdigest));
451 /* Verify the hash */
453 if(!digest_verify(&c->outdigest, c->hischallenge, c->protocol_minor >= 2 ? ECDH_SIZE : rsa_size(&c->rsa), hishash)) {
454 logger(LOG_ERR, "Possible intruder %s (%s): %s", c->name, c->hostname, "wrong challenge reply");
458 /* Identity has now been positively verified.
459 Send an acknowledgement with the rest of the information needed.
462 free(c->hischallenge);
463 c->hischallenge = NULL;
464 c->allow_request = ACK;
469 static bool send_upgrade(connection_t *c) {
470 /* Special case when protocol_minor is 1: the other end is ECDSA capable,
471 * but doesn't know our key yet. So send it now. */
473 char *pubkey = ecdsa_get_base64_public_key(&myself->connection->ecdsa);
478 bool result = send_request(c, "%d %s", ACK, pubkey);
483 bool send_ack(connection_t *c) {
484 if(c->protocol_minor == 1)
485 return send_upgrade(c);
487 /* ACK message contains rest of the information the other end needs
488 to create node_t and edge_t structures. */
493 /* Estimate weight */
495 gettimeofday(&now, NULL);
496 c->estimated_weight = (now.tv_sec - c->start.tv_sec) * 1000 + (now.tv_usec - c->start.tv_usec) / 1000;
498 /* Check some options */
500 if((get_config_bool(lookup_config(c->config_tree, "IndirectData"), &choice) && choice) || myself->options & OPTION_INDIRECT)
501 c->options |= OPTION_INDIRECT;
503 if((get_config_bool(lookup_config(c->config_tree, "TCPOnly"), &choice) && choice) || myself->options & OPTION_TCPONLY)
504 c->options |= OPTION_TCPONLY | OPTION_INDIRECT;
506 if(myself->options & OPTION_PMTU_DISCOVERY)
507 c->options |= OPTION_PMTU_DISCOVERY;
509 choice = myself->options & OPTION_CLAMP_MSS;
510 get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice);
512 c->options |= OPTION_CLAMP_MSS;
514 get_config_int(lookup_config(c->config_tree, "Weight"), &c->estimated_weight);
516 return send_request(c, "%d %s %d %x", ACK, myport, c->estimated_weight, c->options);
519 static void send_everything(connection_t *c) {
520 splay_node_t *node, *node2;
525 /* Send all known subnets and edges */
528 for(node = myself->subnet_tree->head; node; node = node->next) {
530 send_add_subnet(c, s);
536 for(node = node_tree->head; node; node = node->next) {
539 for(node2 = n->subnet_tree->head; node2; node2 = node2->next) {
541 send_add_subnet(c, s);
544 for(node2 = n->edge_tree->head; node2; node2 = node2->next) {
551 static bool upgrade_h(connection_t *c, char *request) {
552 char pubkey[MAX_STRING_SIZE];
554 if(sscanf(request, "%*d " MAX_STRING, pubkey) != 1) {
555 logger(LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name, c->hostname);
559 if(ecdsa_active(&c->ecdsa) || read_ecdsa_public_key(c)) {
560 logger(LOG_INFO, "Already have ECDSA public key from %s (%s), not upgrading.", c->name, c->hostname);
564 logger(LOG_INFO, "Got ECDSA public key from %s (%s), upgrading!", c->name, c->hostname);
565 append_connection_config(c, "ECDSAPublicKey", pubkey);
566 c->allow_request = TERMREQ;
567 return send_termreq(c);
570 bool ack_h(connection_t *c, char *request) {
571 if(c->protocol_minor == 1)
572 return upgrade_h(c, request);
574 char hisport[MAX_STRING_SIZE];
581 if(sscanf(request, "%*d " MAX_STRING " %d %x", hisport, &weight, &options) != 3) {
582 logger(LOG_ERR, "Got bad %s from %s (%s)", "ACK", c->name,
587 /* Check if we already have a node_t for him */
589 n = lookup_node(c->name);
593 n->name = xstrdup(c->name);
597 /* Oh dear, we already have a connection to this node. */
598 ifdebug(CONNECTIONS) logger(LOG_DEBUG, "Established a second connection with %s (%s), closing old connection", n->connection->name, n->connection->hostname);
600 if(n->connection->outgoing) {
602 logger(LOG_WARNING, "Two outgoing connections to the same node!");
604 c->outgoing = n->connection->outgoing;
606 n->connection->outgoing = NULL;
609 terminate_connection(n->connection, false);
610 /* Run graph algorithm to purge key and make sure up/down scripts are rerun with new IP addresses and stuff */
617 if(!(c->options & options & OPTION_PMTU_DISCOVERY)) {
618 c->options &= ~OPTION_PMTU_DISCOVERY;
619 options &= ~OPTION_PMTU_DISCOVERY;
621 c->options |= options;
623 if(get_config_int(lookup_config(c->config_tree, "PMTU"), &mtu) && mtu < n->mtu)
626 if(get_config_int(lookup_config(config_tree, "PMTU"), &mtu) && mtu < n->mtu)
629 if(get_config_bool(lookup_config(c->config_tree, "ClampMSS"), &choice)) {
631 c->options |= OPTION_CLAMP_MSS;
633 c->options &= ~OPTION_CLAMP_MSS;
636 if(c->protocol_minor > 0)
637 c->node->status.ecdh = true;
639 /* Activate this connection */
641 c->allow_request = ALL;
642 c->status.active = true;
644 ifdebug(CONNECTIONS) logger(LOG_NOTICE, "Connection with %s (%s) activated", c->name,
647 /* Send him everything we know */
651 /* Create an edge_t for this connection */
653 c->edge = new_edge();
654 c->edge->from = myself;
656 sockaddr2str(&c->address, &hisaddress, NULL);
657 c->edge->address = str2sockaddr(hisaddress, hisport);
659 c->edge->weight = (weight + c->estimated_weight) / 2;
660 c->edge->connection = c;
661 c->edge->options = c->options;
665 /* Notify everyone of the new edge */
668 send_add_edge(c, c->edge);
670 send_add_edge(broadcast, c->edge);
672 /* Run MST and SSSP algorithms */